阅读说明：本技术 锤钻 (Hammer drill ) 是由 町田吉隆 吉兼圣展 于 2020-10-19 设计创作，主要内容包括：本发明提供一种锤钻。锤钻(101)具有主轴、马达、第一中间轴(41)、冲击机构(6)、第二中间轴(42)和旋转传递机构(7)。马达具有与主轴平行的马达轴(25)。第一中间轴(41)与主轴平行地延伸。冲击机构(6)构成为能够执行锤动作。第二中间轴(42)与第一中间轴(41)平行地延伸。旋转传递机构(7)构成为能够执行钻动作。第一中间轴(41)构成为仅进行用于执行锤动作和钻动作中的锤动作的传递。第二中间轴(42)构成为仅进行用于执行钻动作的传递。根据本发明,能够提供一种可抑制效率的降低的同时有助于使锤钻在驱动轴线方向上变短的技术。(The invention provides a hammer drill. A hammer drill (101) is provided with a main shaft, a motor, a first intermediate shaft (41), an impact mechanism (6), a second intermediate shaft (42), and a rotation transmission mechanism (7). The motor has a motor shaft (25) parallel to the main shaft. A first intermediate shaft (41) extends parallel to the main shaft. The impact mechanism (6) is configured to be capable of performing a hammer action. The second intermediate shaft (42) extends parallel to the first intermediate shaft (41). The rotation transmission mechanism (7) is configured to be capable of performing a drilling operation. The first intermediate shaft (41) is configured to transmit only the hammer motion for performing the hammer motion and the drill motion. The second intermediate shaft (42) is configured to transmit only the power for performing the drilling operation. According to the present invention, it is possible to provide a technique that can contribute to shortening of the hammer drill in the direction of the drive axis while suppressing a decrease in efficiency.)

1. A hammer drill is characterized in that the hammer drill is provided with a hammer drill body,

having a final output shaft, a motor, a first intermediate shaft, a first drive mechanism, a second intermediate shaft, and a second drive mechanism, wherein,

the final output shaft is configured to hold the tip tool so that the tip tool can be detached, and is arranged so as to be rotatable about a drive axis;

the motor having a motor shaft extending parallel to the final output shaft;

the first intermediate shaft extends in parallel with the final output shaft and is configured to be rotatable in accordance with rotation of a motor shaft;

the first driving mechanism is configured to convert a rotational motion of the first intermediate shaft into a linear motion, and is capable of performing a hammer operation of linearly driving the tip tool along the driving axis;

the second intermediate shaft extends in parallel with the first intermediate shaft and is configured to be rotatable in accordance with rotation of the motor shaft;

the second drive mechanism is configured to transmit rotation of the second intermediate shaft to the final output shaft and to be capable of performing a drilling operation for driving the tip end tool to rotate about the drive axis,

the first intermediate shaft is configured to transmit only the hammer motion for performing one of the hammer motion and the drill motion,

the second intermediate shaft is configured to transmit only the drill motion of the hammer motion and the drill motion.

2. The hammer drill according to claim 1,

the motor shaft is provided with a driving gear,

the first and second countershafts have first and second driven gears, respectively, that directly mesh with the drive gear.

3. The hammer drill according to claim 2,

an angle formed by a line segment connecting the rotation axis of the motor shaft and the rotation axis of the first intermediate shaft and a line segment connecting the rotation axis of the motor shaft and the rotation axis of the second intermediate shaft on a plane orthogonal to the drive axis is an obtuse angle.

4. Hammer drill according to any one of claims 1 to 3,

the transmission control device further includes a torque limiter disposed on the second intermediate shaft and configured to interrupt transmission when a torque acting on the second intermediate shaft exceeds a threshold value.

5. Hammer drill according to claim 4,

the torque limiter includes a driving-side cam, a driven-side cam, and balls, wherein,

the driven side cam can be clamped with the driving side cam;

the balls are configured to be capable of rolling in a track extending in an axial direction of the second intermediate shaft between an inner periphery of one of the drive-side cam and the driven-side cam and an outer periphery of the second intermediate shaft,

the one of the driving-side cam and the driven-side cam is configured to move in the axial direction in a direction away from the other one of the driving-side cam and the driven-side cam while being guided by the balls and to release engagement with the other one of the driving-side cam and the driven-side cam when a torque acting on the second intermediate shaft exceeds a threshold value.

6. The hammer drill according to claim 5,

the torque limiter includes an urging member that urges the one of the driving-side cam and the driven-side cam toward the other.

7. Hammer drill according to any one of claims 1 to 6,

the extending direction of the drive axis is defined as the front-rear direction of the hammer drill, the extending direction of an axis orthogonal to the drive axis and the rotation axis of the motor shaft is defined as the vertical direction, and the direction orthogonal to the front-rear direction and the vertical direction is defined as the horizontal direction,

and a side where the tip tool is attached is defined as a front side in the front-rear direction, and a side where the rotation axis of the motor shaft is arranged with respect to the drive axis is defined as a lower side in the up-down direction,

in this case, the rotational axis of the first intermediate shaft is arranged on the right side with respect to the drive axis, and the rotational axis of the second intermediate shaft is arranged on the left side with respect to the drive axis.

8. The hammer drill according to any one of claims 1 to 7,

also provided are a housing and a dividing member, wherein,

the dividing member is fixedly attached to the housing and configured to divide an interior of the housing into a first region and a second region in an axial direction of the final output shaft,

the final output shaft, the first intermediate shaft, the first drive mechanism, the second intermediate shaft, and the second drive mechanism are housed in the first region,

the motor is accommodated in the second area,

the dividing member supports a first bearing of the motor shaft, a second bearing of the first intermediate shaft, and a third bearing of the second intermediate shaft.

9. Hammer drill according to any one of claims 1 to 8,

there is also a first clutch mechanism and a second clutch mechanism, wherein,

the first clutch mechanism is provided on the first intermediate shaft and configured to transmit or cut off power for the hammer operation;

the second clutch mechanism is provided on the second intermediate shaft and configured to transmit or cut off power for the drill operation.

10. The hammer drill according to claim 9,

further comprising an operation member configured to be manually operated by a user for switching an operation mode of the hammer drill,

the first clutch mechanism and the second clutch mechanism are each configured to be switched between a power transmission state and a cut-off state in response to a manual operation of the operating member.

11. The hammer drill according to claim 10,

and a first switching member and a second switching member, wherein,

the first switching member is configured to switch the first clutch mechanism between the power transmission state and the disengaged state in response to movement of the operating member in response to the manual operation;

the second switching member is configured to be moved in response to the manual operation to switch the second clutch mechanism between the power transmission state and the cut-off state.

12. The hammer drill according to claim 11,

the operating member has a first abutting portion and a second abutting portion, wherein,

the first contact portion is configured to contact the first switching member and move the first switching member;

the second contact portion is configured to contact the second switching member and move the second switching member.

13. Hammer drill according to claim 11 or 12,

the first switching member and the second switching member are supported by a single support member so as to be movable relative to the support member.

14. Hammer drill according to any one of claims 1 to 13,

there is also a handle extending along an axis that intersects the drive axis,

the handle is located on a side opposite to the tip tool with respect to the first intermediate shaft and the second intermediate shaft in an axial direction of the final output shaft.

15. The hammer drill according to claim 14,

the handle is located on the opposite side of the motor from the tip tool in the axial direction of the final output shaft.

Technical Field

The present invention relates to a hammer drill capable of performing an operation of linearly driving a tip tool and an operation of rotationally driving the tip tool.

Background

The hammer drill is configured to be capable of performing a hammer action for linearly driving a tip tool attached to a tool holder along a driving axis and a drill action; the drilling action is an action of rotationally driving the tip tool about a drive axis. In general, a motion conversion mechanism that converts a rotational motion of an intermediate shaft into a linear motion is used to perform a hammer operation, and a rotation transmission mechanism that transmits a rotation to a tool holder via the intermediate shaft is used to perform a drill operation. For example, in a hammer drill disclosed in japanese patent laid-open publication No. 2016-. In contrast, in the hammer drill disclosed in european patent application No. 2700477, the motion conversion mechanism and the rotation transmission mechanism are provided with separate intermediate shafts.

Disclosure of Invention

[ problem to be solved by the invention ]

In the hammer drill of japanese patent laid-open publication No. 2016-. In the hammer drill described in european patent application No. 2700477, two intermediate shafts are connected in series in a power transmission path, and after the main shaft is decelerated and rotated by the intermediate shaft of the rotation transmission mechanism, the main shaft accelerates and rotates the intermediate shaft of the motion conversion mechanism. Therefore, the efficiency may be reduced.

In view of the above circumstances, an object of the present invention is to provide a technique that can contribute to shortening of a hammer drill in a direction of a drive axis while suppressing a decrease in efficiency.

[ solution for solving problems ]

According to one aspect of the present invention, a hammer drill is provided having a final output shaft, a motor, a first intermediate shaft, a first drive mechanism, a second intermediate shaft, and a second drive mechanism.

The final output shaft is configured to removably retain the tip tool. In addition, the final output shaft is disposed so as to be rotatable about the drive axis. The motor has a motor shaft extending parallel to the final output shaft. The first intermediate shaft extends parallel to the final output shaft and is configured to be rotatable in accordance with rotation of the motor shaft. The first drive mechanism is configured to convert the rotational motion of the first intermediate shaft into a linear motion, and is capable of performing a hammer operation for linearly driving the tip tool along the drive axis. The second intermediate shaft extends parallel to the first intermediate shaft and is configured to be rotatable in accordance with rotation of the motor shaft. The second drive mechanism is configured to transmit rotation of the second intermediate shaft to the final output shaft, and is capable of performing a drilling operation for driving the tip end tool to rotate about the drive axis.

The first intermediate shaft is configured to transmit only the hammer motion for executing the hammer motion and the drill motion. The second intermediate shaft is configured to transmit only a drill motion for performing the hammer motion and the drill motion. The first intermediate shaft "performs only transmission for executing the hammer action" means that transmission for executing the drill action is not performed, and transmission for the purpose of executing actions other than the drill action is not excluded. Similarly, the meaning of the second intermediate shaft "performing only transmission for performing the drill action" means that transmission for performing the hammer action is not performed, and does not exclude transmission for the purpose of performing actions other than the hammer action.

The hammer drill according to the present invention has two independent intermediate shafts (a first intermediate shaft and a second intermediate shaft) extending parallel to a drive shaft and performing power transmission for hammer operation and drill operation, respectively. Therefore, the first intermediate shaft and the second intermediate shaft can be shortened as compared with the case of using one common intermediate shaft. This makes it possible to shorten the entire hammer drill in the direction of the drive axis. In addition, the first and second intermediate shafts are specialized for power transmission for hammer action and power transmission for drill action, respectively. That is, the power transmission path dedicated to the hammer action and the power transmission path dedicated to the drill action are not provided in series but in parallel. Therefore, the power transmission from the first intermediate shaft to the first drive mechanism and the power transmission from the second intermediate shaft to the second drive mechanism can be optimized, and the power transmission to the final output shaft can be optimized.

In one embodiment of the present invention, the following steps may be performed: the motor shaft has a drive gear, and the first and second countershafts have first and second driven gears, respectively, that directly mesh with the drive gear. In this case, since the first driven gear and the second driven gear are engaged with the drive gear of the motor shaft from two directions, it is possible to suppress the bending load in a specific one direction from being applied to the drive gear. In the present aspect, it is preferable that an angle formed by a line segment connecting the rotation axis of the motor shaft and the rotation axis of the first intermediate shaft and a line segment connecting the rotation axis of the motor shaft and the rotation axis of the second intermediate shaft on a plane orthogonal to the drive axis is an obtuse angle. In this case, the first driven gear and the second driven gear can be prevented from being increased in size as compared with a case where the first driven gear and the second driven gear are arranged on a straight line with the drive gear as the center.

In one aspect of the present invention, the hammer drill may further include a torque limiter disposed on the second intermediate shaft and configured to interrupt transmission when a torque acting on the second intermediate shaft exceeds a threshold value. In this case, the space that can be generated in the second intermediate shaft dedicated to power transmission for the drill operation can be effectively utilized, and the torque limiter can be arranged appropriately.

In an aspect of the present invention, the torque limiter may include a driving side cam, a driven side cam, and a ball. The driven cam may be configured to be engageable with the driving cam. The balls may be configured to be capable of rolling in a track extending in the axial direction of the second intermediate shaft between an inner periphery of one of the drive-side cam and the driven-side cam and an outer periphery of the second intermediate shaft. In addition, when the torque acting on the second intermediate shaft exceeds a threshold value, one of the driving-side cam and the driven-side cam may be configured to move in the axial direction in a direction away from the other of the driving-side cam and the driven-side cam while being guided by the balls, thereby releasing the engagement with the other. In this case, the friction between one of the driving side cam and the driven side cam and the second intermediate shaft during the operation of the torque limiter can be reduced, and the operation torque can be stabilized.

In one aspect of the present invention, the torque limiter may include an urging member that urges one of the driving-side cam and the driven-side cam toward the other.

In one embodiment of the present invention, the following steps may be performed: in this case, the rotation axis of the first intermediate shaft is disposed on the right side with respect to the drive axis, and the rotation axis of the second intermediate shaft is disposed on the left side with respect to the drive axis. In this case, a good weight balance in the left-right direction can be achieved as compared with a case where the first intermediate shaft and the second intermediate shaft are disposed offset to the left or right.

In one aspect of the present invention, the hammer drill may further include a housing and a partition member. The dividing member may be fixedly mounted to the housing. The dividing member may be configured to divide the interior of the housing into a first region and a second region in the axial direction of the final output shaft. The final output shaft, the first intermediate shaft, the first drive mechanism, the second intermediate shaft, and the second drive mechanism may be housed in the first region. The motor may be housed in the second region. The dividing member may support a first bearing of the motor shaft, a second bearing of the first intermediate shaft, and a third bearing of the second intermediate shaft.

In one aspect of the present invention, the hammer drill may further include a first clutch mechanism and a second clutch mechanism. The first clutch mechanism may be provided on the first intermediate shaft and configured to transmit or cut off power for the hammer action. The second clutch mechanism may be provided on the second intermediate shaft and configured to transmit or cut off power for the drill action. In this case, the power for the hammer operation and the power for the drill operation can be cut off by using the first clutch mechanism and the second clutch mechanism, respectively, as necessary.

In one aspect of the present invention, the hammer drill may further include an operation member for switching an operation mode of the hammer drill. The operation member may be configured to be manually operated by a user. Each of the first clutch mechanism and the second clutch mechanism may be configured to be switched between a power transmission state and a cut-off state in response to an operation of the operating member. In this case, the user can operate the first clutch mechanism and the second clutch mechanism by operating a single operation member and switching the operation mode according to a desired task.

In one aspect of the present invention, the hammer drill may further include a first switching member and a second switching member. The first switching member may be configured to be moved in response to a manual operation of the operating member to switch the first clutch mechanism between the power transmission state and the disengaged state. The second switching member may be configured to be moved in response to a manual operation of the operating member to switch the second clutch mechanism between the power transmission state and the disengaged state.

In one aspect of the present invention, the operating member may have a first abutting portion and a second abutting portion. The first contact portion may be configured to contact the first switching member and move the first switching member. The second contact portion may be configured to contact the second switching member and move the second switching member.

In one aspect of the present invention, the first switching member and the second switching member may be supported by a single support member so as to be movable relative to the support member.

In one aspect of the invention, the hammer drill may further have a handle extending along an axis that intersects the drive axis. The handle may be located on the opposite side of the tip tool with respect to the first intermediate shaft and the second intermediate shaft in the axial direction of the final output shaft.

In one aspect of the present invention, the handle may be located on the opposite side of the final output shaft from the top end tool with respect to the motor in the axial direction of the final output shaft.

Drawings

FIG. 1 is a cross-sectional view of a hammer drill.

Fig. 2 is a partially enlarged view of the hammer drill.

FIG. 3 is a cross-sectional view II-II of FIG. 2.

Fig. 4 is a cross-sectional view of a modified example of the bearing support body.

Fig. 5 is a cross-sectional view of V-V of fig. 2.

Fig. 6 is a cross-sectional view of VI-VI of fig. 5.

Fig. 7 is a cross-sectional view of VI I-VI I of fig. 5.

FIG. 8 is a cross-sectional view of VI I-VI I of FIG. 5.

Fig. 9 is a partially enlarged view of fig. 7.

Fig. 10 is a partially enlarged view of fig. 8.

Fig. 11 is a diagram corresponding to fig. 10 and illustrating an operation of the torque limiter.

Fig. 12 is a partial bottom view of the hammer drill with the front housing removed, and shows the mode switching mechanism when the hammer drill mode is selected.

Fig. 13 is a diagram showing the mode switching mechanism when the hammer mode is selected.

Fig. 14 is a diagram showing the mode switching mechanism when the drill mode is selected.

FIG. 15 is a cross-sectional view of XV-XV of FIG. 5.

Fig. 16 is a cross-sectional view of XVI-XVI of fig. 5.

Fig. 17 is a cross-sectional view of XVI-XVI of fig. 5.

Fig. 18 is an explanatory diagram of a method of determining the reference guide axis.

Fig. 19 is an explanatory view of the assembly of the lock plate.

Fig. 20 is an explanatory view of the assembly of the lock plate.

Fig. 21 is an explanatory view of the assembly of the lock plate.

Fig. 22 is a partially enlarged view of fig. 7.

Fig. 23 is a view corresponding to fig. 22 and illustrating an operation of the air-raid preventing mechanism.

Fig. 24 is an explanatory diagram of a modification of the cushion ring.

Fig. 25 is an explanatory diagram of a modification of the cushion ring.

Fig. 26 is an explanatory diagram of a modification of the cushion ring.

Fig. 27 is an explanatory diagram of a modification of the cushion ring.

[ description of reference numerals ]

101, a hammer drill; 10: a main body case; 11: a rear housing; 13: a front housing; 131: a barrel portion; 133: a shoulder portion; 137: a rib; 138: a recess; 15: a bearing support body; 151: an O-shaped ring; 152: an elastomer; 153: an exhaust hole; 154: a filter; 155: a protrusion; 157: a protrusion; 17: a handle; 171: a trigger; 172: a switch; 179: a power line; 18: a movable support; 180: a movable unit; 181: a first shaft penetration insertion part; 182: a second shaft through insertion part; 183: a cylindrical portion; 184: a bearing; 185: a spindle support; 187: a rotating body support portion; 190: a support hole; 191: a first guide shaft; 192: a second guide shaft; 194: a first force application spring; 195: a second force application spring; 197: a buffer member; 2: a motor; 20: a main body portion; 25: a motor shaft; 251: a bearing; 252: a bearing; 255: a pinion gear; 27: a fan; 30: a runaway prevention mechanism; 31: a main shaft; 316: a bearing; 317: a bearing; 32: a tool holder; 321: a small diameter part; 322: a first shoulder; 323: a rear surface; 325: a large diameter portion; 326: a second shoulder; 329: a maximum diameter part; 33: a cylinder; 330: a drill bit is inserted into the hole; 34: a catcher; 341: a catching ring; 343: a ring holding portion; 345: a retainer ring; 35: confinement ring, 36: a guide sleeve; 360: a guide section; 361: a small diameter part; 363: a large diameter portion; 364: a front surface; 37. 371, 372: a buffer ring; 373: an O-shaped ring; 38: a buffer ring; 39: oil sealing; 41: a first intermediate shaft; 411: a bearing; 412: a bearing; 414: a first driven gear; 416: a spline section; 417: a large diameter portion; 42: a second intermediate shaft; 421: a bearing; 422: a bearing; 423: a gear component; 424: a second driven gear; 425: a spline section; 426: a groove; 45: a locking plate; 451: a spring receiving part; 453: an abutting portion; 455: a locking part; 46: a force application spring; 5: a drive mechanism; 6: an impact mechanism; 61: a motion conversion member; 611: a rotating body; 612: a spline section; 614: a bearing; 616: a swinging member; 617: an arm portion; 62: a first clutch mechanism; 63: a clamping member; 631: a spline section; 64: a first transfer member; 641: a first spline section; 642: a second spline portion; 645: a groove; 65: a piston; 67: a ram; 671: a main body portion; 672: a small diameter part; 673: a flange portion; 68: an impact bolt; 681: a large diameter portion; 683: a small diameter part; 684: a small diameter part; 7: a rotation transmission mechanism; 71: a second clutch mechanism; 72: a second transmission member; 721: a first spline section; 722: a second spline portion; 725: a groove; 727: a recess; 73: a torque limiter; 74: a drive side member; 742: a cam recess; 743: a spline section; 75: a driven-side member; 751: a groove; 752: a cam protrusion; 76: a ball bearing; 77: a force application spring; 78: a drive gear; 79: a driven gear; 80: a mode switching mechanism; 800: a mode switching dial; 801: an operation section; 803: a first pin; 805: a second pin; 81: a first switching member; 813: a first engaging portion; 82: a second switching member; 823: a second engaging portion; 83: a first spring; 84: a second spring; 88: a support shaft; 881: a retainer ring; 91: a tip tool; a1: a drive axis; a2: a rotation axis; a3: a rotation axis; a4: an axis of rotation.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, the hammer drill 101 is illustrated as an example of an impact tool. The hammer drill 101 is a hand-held electric tool used for machining operations such as chipping and drilling operations, and is configured to be capable of performing an operation of linearly driving the tip tool 91 along a predetermined drive axis a1 (hereinafter referred to as a hammer operation) and an operation of rotationally driving the tip tool 91 about a drive axis a1 (hereinafter referred to as a drilling operation).

First, a schematic configuration of the hammer drill 101 will be briefly described with reference to fig. 1. As shown in fig. 1, the outer contour of the hammer drill 101 is mainly formed by the body housing 10 and the handle 17 coupled to the body housing 10.

The main body case 10 is a hollow body also called a tool main body or an outer shell case, and houses the spindle 31, the motor 2, the drive mechanism 5, and the like. The spindle 31 is a long cylindrical member, and has a tool holder 32 detachably holding a tip tool 91 at one end portion in the axial direction. The long axis of the spindle 31 defines a drive axis a1 of the tip tool 91. The main body case 10 extends along a drive axis a 1. The tool holder 32 is disposed in one end portion of the main body case 10 in the extending direction of the drive axis a1 (hereinafter, simply referred to as the drive axis direction).

The handle 17 is an elongated hollow body for a user to hold. One end portion in the axial direction of the handle 17 is coupled to the other end portion (the end portion on the side opposite to the side on which the tool holder 32 is disposed) in the driving axis direction of the main body case 10. The handle 17 extends in a direction (more specifically, a direction substantially perpendicular to) intersecting the drive axis a1 so as to protrude from the other end of the main body case 10. In the present embodiment, the main body case 10 and the handle 17 are integrated by coupling a plurality of components with screws or the like. A power cord 179 is extended from the protruding end of the handle 17 to be connectable to an external ac power source. The handle 17 includes a trigger 171 that is pushed (pulled) by a user, and a switch 172 that is turned on in response to the pushing operation of the trigger 171.

In the hammer drill 101, when the switch 172 is in the on state, the motor 2 is energized, and the drive mechanism 5 is driven, thereby performing the hammer operation and/or the drill operation.

The detailed structure of the hammer drill 101 will be described below. In the following description, for convenience, the extending direction of the drive axis a1 (the longitudinal direction of the body case 10) is defined as the front-rear direction of the hammer drill 101. In the front-rear direction, the one end side on which the tool holder 32 is disposed is defined as the front side of the hammer drill 101, and the opposite side (the side to which the handle 17 is connected) is defined as the rear side. The direction perpendicular to the drive axis a1 and corresponding to the axial direction of the handle 17 is defined as the vertical direction of the hammer drill 101. In the vertical direction, the side of the main body case 10 to which the handle 17 is connected is defined as an upper side, and the projecting end side of the handle 17 is defined as a lower side. In addition, a direction orthogonal to the front-rear direction and the up-down direction is defined as a left-right direction.

First, the structure of the main body case 10 will be described.

As shown in fig. 1, the main body case 10 has a cylindrical front end portion. This cylindrical portion is referred to as a cylinder 131. The main body case 10 is formed in a substantially rectangular box shape except for the cylindrical portion 131. An assist grip (not shown) can be attached to the tube 131. In addition to the grip 17, the user can also assist in gripping the cylindrical portion 131 to which the assist grip is not attached.

The internal space of the main body case 10 is divided into two regions by a bearing support body 15 disposed inside the main body case 10. The bearing support body 15 is disposed so as to intersect the drive axis a1, is fitted into the inner periphery of the main body case 10, and is held in a fixed state (immovable with respect to the main body case 10) by the main body case 10. The rear region of the bearing support body 15 is mainly a region for accommodating the motor 2. The front region of the bearing support body 15 is mainly a region for accommodating the main shaft 31 and the drive mechanism 5. Hereinafter, a portion of the main body case 10 corresponding to the housing area of the motor 2 is referred to as a rear case 11, and a portion of the main body case 10 corresponding to the housing area of the main shaft 31 and the drive mechanism 5 (including the cylindrical portion 131) is referred to as a front case 13.

The rear case 11 and the front case 13 are both made of resin (plastic). The rear housing 11 is formed by coupling a plurality of members. On the other hand, the front housing 13 is a single cylindrical member.

In the present embodiment, the bearing support body 15 is also formed of resin (plastic). This is because the vibration-proof structure described later suppresses transmission of vibration generated by the drive mechanism 5 to the main body case 10 and the bearing support body 15 fixedly attached to the main body case 10, and therefore the bearing support body 15 is not required to have strength of a metal level. Accordingly, the weight of the hammer drill 101 can be reduced as compared with the case where the bearing support body 15 is formed of metal. As shown in fig. 2, the bearing support body 15 is fitted into the rear end portion of the front housing 13 so that substantially the entire outer peripheral surface thereof comes into contact with the inner peripheral surface of the front housing 13.

As will be described in detail later, the bearing support body 15 is a member that supports bearings of various shafts. Therefore, high accuracy is required for the dimension of the outer periphery fitted into the main body case 10. Therefore, when such a bearing support body 15 is formed of metal (for example, aluminum alloy), it is preferable to perform machining on a single circle basis for dimensional accuracy. In contrast, in the present embodiment, the bearing support body 15 is formed of resin, thereby increasing the degree of freedom in shape. Specifically, as shown in fig. 3, the sectional shape of the bearing support body 15 in a plane orthogonal to the drive axis a1 is not based on a single circle, but is based on three circles. Therefore, the outer periphery of the bearing support body 15 (i.e., the contact portion with the main body case 10) is not on the circumference of a single circle, but a part of the outer periphery of the bearing support body 15 is overlapped on each of the three circles.

As shown in fig. 2, an annular groove is formed in the outer peripheral surface of the bearing support 15 that contacts the inner peripheral surface of the main body housing 10. A rubber O-ring 151 is fitted in the groove. The lubricant is provided in the front housing 13 that houses the drive mechanism 5. The O-ring 151 functions as a sealing member that closes the gap between the main body housing 10 and the bearing support body 15, and can prevent the lubricant from leaking into the rear housing 11 through the gap between the main body housing 10 and the bearing support body 15. As the sealing member, for example, as shown in fig. 4, instead of the O-ring 151 disposed separately from the bearing support body 15, an elastic body 152 made of a thermoplastic elastomer may be integrally molded on the outer periphery of the resin bearing support body 15. In this case, the bearing support body 15 with the elastic body 152 can be easily assembled to the main body case 10.

As shown in fig. 3 and 5, bearing support body 15 is provided with a gas discharge hole 153 that communicates the internal space of front housing 13 with the internal space of rear housing 11 in order to adjust the pressure in front housing 13 to match the pressure in rear housing 11. A filter 154 is fitted into the exhaust hole 153, and the filter 154 prevents the lubricant from leaking into the rear case 11 through the exhaust hole 153 (see fig. 17).

The internal structure of the main body case 10 will be described below.

First, the motor 2 will be explained. In the present embodiment, an ac motor driven by electric power supplied from an external ac power supply is used as the motor 2. As shown in fig. 1, the motor 2 has a main body portion 20 and a motor shaft 25, wherein the main body portion 20 includes a stator and a rotor; the motor shaft 25 is configured to rotate integrally with the rotor. The stator is fixed to the rear housing 11 by screws. In the present embodiment, the rotation axis a2 of the motor shaft 25 extends in parallel with the drive axis a1 at a position lower than the drive axis a 1. A virtual plane VP (hereinafter, referred to as a reference plane VP) (see fig. 3 and 5) including the drive axis a1 and the rotation axis a2 extends in the vertical direction of the hammer drill 101.

The motor shaft 25 is supported by the main body case 10 via two bearings 251 and 252 so as to be rotatable about a rotation axis a2 with respect to the main body case 10. The front bearing 251 is held on the rear surface side of the bearing support body 15, and the rear bearing 252 is held by the rear housing 11 (specifically, an inner housing that accommodates the motor 2 in the rear housing 11). A fan 27 for cooling the motor 2 is fixed to a portion of the motor shaft 25 between the main body 20 and the front bearing 251. The front end of the motor shaft 25 penetrates the bearing support body 15 and protrudes into the front housing 13. A pinion 255 is fixed to the portion protruding into the front housing 13.

Next, a power transmission path from the motor shaft 25 to the drive mechanism 5 will be described.

As shown in fig. 5 and 6, in the present embodiment, the hammer drill 101 has two intermediate shafts (the first intermediate shaft 41 and the second intermediate shaft 42). The drive mechanism 5 is configured to perform a hammer operation by the power transmitted from the first intermediate shaft 41 and a drill operation by the power transmitted from the second intermediate shaft 42. That is, the first intermediate shaft 41 is a shaft dedicated to power transmission for hammer operation. The second intermediate shaft 42 is a shaft dedicated to power transmission for drill operation.

Both the first countershaft 41 and the second countershaft 42 extend within the front housing 13 parallel to the drive axis a1 and the rotational axis a 2. The first intermediate shaft 41 is supported by the main body case 10 via two bearings 411 and 412 so as to be rotatable about the rotation axis a3 with respect to the main body case 10. The front bearing 411 is held by the front housing 13, and the rear bearing 412 is held by the front surface side of the bearing support body 15. Similarly, the second intermediate shaft 42 is supported by the main body case 10 via two bearings 421 and 422 so as to be rotatable about the rotation axis a4 with respect to the main body case 10. The front bearing 421 is held by the front housing 13, and the rear bearing 422 is held by the front surface side of the bearing support body 15. As described above, since the bearing 251 of the motor shaft 25 is also supported by the bearing support body 15, the motor shaft 25, the first intermediate shaft 41, and the second intermediate shaft 42 can be arranged with high precision.

The first intermediate shaft 41 is disposed on the right side with respect to the reference plane VP. Second intermediate shaft 42 is disposed on the left side with respect to reference plane VP. Accordingly, as compared with the case where the first intermediate shaft 41 and the second intermediate shaft 42 are disposed offset to the left or right, a good weight balance in the left-right direction can be achieved.

In addition, on a plane orthogonal to the drive axis a1, an angle formed by a line segment connecting the rotation axis a2 of the motor shaft 25 and the rotation axis A3 of the first intermediate shaft 41 and a line segment connecting the rotation axis a2 and the rotation axis a4 of the second intermediate shaft 42 is an obtuse angle.

A first driven gear 414 is fixed to a rear end portion of the first intermediate shaft 41 adjacent to a front side of the bearing 412. A gear member 423 having a second driven gear 424 is disposed adjacent to the front side of the bearing 422 at the rear end portion of the second intermediate shaft 42. The first driven gear 414 and the second driven gear 424 are engaged with the pinion 255 of the motor shaft 25. By the above-described arrangement of the rotation axes a2, A3, and a4, the first driven gear 414 and the second driven gear 424 are caused to mesh with the pinion 255 from substantially opposite directions. Therefore, the pinion gear 255 can be restrained from being subjected to a bending load in a specific one direction. In addition, as compared with the case where the first driven gear 414 and the second driven gear 424 are arranged on a straight line with the pinion 255 as the center, it is possible to arrange necessary components reasonably in the first countershaft 41 and the second countershaft 42 while suppressing an increase in the size of the entire drive mechanism 5 in the straight line direction.

The gear member 423 is formed in a cylindrical shape and is disposed on the outer peripheral side of the second intermediate shaft 42 (in detail, a drive-side member 74 described later). Further, a spline portion 425 is provided on the outer periphery of the cylindrical front end portion of the gear member 423. The spline portion 425 has a plurality of splines (external teeth) extending in the direction of the rotation axis a4 (front-rear direction). The rotation of the second driven gear 424 (gear member 423) is transmitted to the second intermediate shaft 42 via the second transmission member 72 and the torque limiter 73, which will be described later in detail.

As described above, in the present embodiment, two power transmission paths branched from the motor shaft 25 are provided, and these paths are used as a power transmission path dedicated to hammer actuation and a power transmission path dedicated to drill actuation, respectively.

The main shaft 31 will be explained. The main shaft 31 is the final output shaft of the hammer drill 101. As shown in fig. 2, the spindle 31 is disposed in the front housing 13 along the drive axis a1, and is supported by the main body housing 10 so as to be rotatable about the drive axis a1 with respect to the main body housing 10. The main shaft 31 is configured as an elongated stepped cylindrical member.

The front half of the spindle 31 constitutes a tool holder 32 to which the tip tool 91 can be attached and detached. The tip tool 91 is inserted into the bit insertion hole 330 at the front end of the tool holder 32 so that the long axis thereof coincides with the drive axis a1, and is held in a state of being allowed to move in the axial direction relative to the tool holder 32 and being restricted from rotating about the axis. The rear half of the main shaft 31 constitutes a cylinder 33 which slidably holds a piston 65 described later. In the present embodiment, the spindle 31 is a single member in which the tool holder 32 and the cylinder 33 are integrally formed, but may be formed by coupling a plurality of members. The main shaft 31 is made of iron (or an alloy containing iron as a main component). The main shaft 31 is supported by a bearing 316 held in the cylindrical portion 131 and a bearing 317 held by a movable support 18 described later.

The driving mechanism 5 will be explained below. As shown in fig. 6 to 8, in the present embodiment, the drive mechanism 5 includes the impact mechanism 6 and the rotation transmission mechanism 7. The impact mechanism 6 is a mechanism for executing a hammer action, and is configured to convert a rotational motion of the first intermediate shaft 41 into a linear motion and linearly drive the tip tool 91 along the drive axis a 1. The rotation transmission mechanism 7 is a mechanism for executing a drilling operation, and is configured to transmit the rotational motion of the second intermediate shaft 42 to the main shaft 31 and rotationally drive the tip tool 91 around the drive axis a 1. The details of the impact mechanism 6 and the rotation transmission mechanism 7 will be described in order below.

In the present embodiment, as shown in fig. 6 and 7, the impact mechanism 6 includes a motion conversion member 61, a piston 65, a hammer 67, and an impact bolt 68.

The motion conversion member 61 is disposed on the first intermediate shaft 41, and is configured to convert the rotational motion of the first intermediate shaft 41 into a linear motion and transmit the linear motion to the piston 65. In more detail, the motion converting part 61 includes a rotating body 611 and a swinging part 616. The rotating body 611 is supported by the main body case 10 via a bearing 614 so as to be rotatable about the rotation axis a3 with respect to the main body case 10. The swinging member 616 is rotatably attached to the outer periphery of the rotating body 611, and configured to swing in the extending direction (front-rear direction) of the rotation axis a3 in accordance with the rotation of the rotating body 611. The swinging member 616 has an arm portion 617 extending upward from the rotating body 611.

The piston 65 is a bottomed cylindrical member, and is disposed in the cylinder 33 of the main shaft 31 so as to be slidable along the drive axis a 1. The piston 65 is coupled to the arm portion 617 of the swinging member 616 by a coupling pin, and reciprocates in the front-rear direction in accordance with the swinging of the swinging member 616.

The hammer 67 is an impact member for applying an impact force to the tip tool 91. The hammer 67 is disposed in the piston 65 so as to be slidable along the drive axis a 1. The internal space of the piston 65 on the rear side of the hammer 67 is defined as an air chamber functioning as an air spring. The impact pin 68 is an intermediate member that transmits the kinetic energy of the ram 67 to the tip tool 91. The impact bolt 68 is disposed on the front side of the hammer 67 so as to be movable along the drive axis a1 in the tool holder 32. In the present embodiment, the impact bolt 68 is slidably held in the front-rear direction by the guide sleeve 36 and the retainer ring 35 disposed in the tool holder 32.

When the piston 65 moves in the front-rear direction in accordance with the swing of the swing member 616, the air pressure of the air chamber fluctuates, and the ram 67 slides in the front-rear direction in the piston 65 by the air spring. More specifically, when the piston 65 moves forward, air in the air chamber is compressed to increase the internal pressure. The ram 67 is pushed forward at high speed by the air spring and strikes the impact bolt 68. The impact bolt 68 transfers the kinetic energy of the ram 67 to the tip tool 91. Accordingly, the tip tool 91 is linearly driven along the driving axis a 1. On the other hand, when the piston 65 moves rearward, air in the air chamber expands to lower the internal pressure, and the hammer 67 is pulled rearward. The tip tool 91 moves rearward together with the impact pin 68 by being pressed against the workpiece. In this way, the hammer operation is repeated by the impact mechanism 6.

In the present embodiment, the rotational motion of the first intermediate shaft 41 is transmitted to the motion conversion member 61 (specifically, the rotating body 611) via the first transmission member 64 and the intermediate member 63. The intermediate member 63 and the first transmission member 64 will be described in order below.

As shown in fig. 6 and 9, the interposed member 63 is a cylindrical member that is disposed coaxially with the first intermediate shaft 41 around the first intermediate shaft 41 and is interposed between the first intermediate shaft 41 and the motion conversion member 61 (specifically, the rotating body 611). The intermediate member 63 is immovable in the front-rear direction with respect to the first intermediate shaft 41, and is rotatable about the rotation axis a3 with respect to the first intermediate shaft 41.

More specifically, the front end portion of the first intermediate shaft 41 (the portion adjacent to the rear side of the front bearing 411) is configured as a maximum diameter portion having the maximum outer diameter. A spline portion 416 is provided on the outer periphery of the maximum diameter portion. The spline portion 416 has a plurality of splines (external teeth) extending in the direction of the rotation axis a3 (front-rear direction). The intermediate member 63 is held between the spline portion 416 and the first driven gear 414 fixed to the rear end portion of the first intermediate shaft 41 so as not to be movable in the front-rear direction. Further, a portion of the first intermediate shaft 41 adjacent to the rear side of the spline portion 416 is configured as a large diameter portion 417, and the large diameter portion 417 has a slightly larger outer diameter than a portion thereof on the rear side.

Further, a spline portion 631 extending over substantially the entire length of the intermediate member 63 is provided on the outer periphery of the intermediate member 63. The spline portion 631 has a plurality of splines (external teeth) extending in the direction of the rotation axis a3 (front-rear direction). Further, the spline portion 631 of the intermediate member 63 has a diameter larger than that of the spline portion 416 of the first intermediate shaft 41.

On the other hand, a spline portion 612 is formed on the inner periphery of the rotating body 611. The spline portion 612 has splines (internal teeth) that engage with the spline portion 631. The intermediate member 63 is always spline-engaged with the rotating body 611 and is held by the rotating body 611. With such a configuration, the rotating body 611 is movable in the direction of the rotation axis a3 (front-rear direction) with respect to the intermediate member 63 and the first intermediate shaft 41, and is rotatable integrally with the intermediate member 63.

The first transmission member 64 is disposed on the first intermediate shaft 41, is configured to be rotatable integrally with the first intermediate shaft 41, and is movable in the direction of the rotation axis a3 (front-rear direction) with respect to the first intermediate shaft 41 and the intermediate member 63.

More specifically, the first transmission member 64 is a substantially cylindrical member disposed around the first intermediate shaft 41, and the first spline portion 641 and the second spline portion 642 are provided on the inner periphery of the first transmission member 64.

The first spline portion 641 is provided at the rear end portion of the first transmission member 64. The first spline portion 641 has a plurality of splines (internal teeth) that can engage with the spline portion 631 of the intermediate member 63. As described above, the spline portion 631 of the intermediate member 63 also engages with the spline portion 612 of the rotating body 611. That is, the spline portion 631 is effectively used for engagement with two members, i.e., the rotating body 611 and the first transmission member 64. The second spline portion 642 is provided at the front half portion of the first transfer member 64. The second spline portion 642 has a plurality of splines (internal teeth) that are constantly engaged with the spline portion 416 of the first intermediate shaft 41.

According to such a configuration, as shown by a solid line in fig. 9, when the first spline portion 641 is disposed at a position (hereinafter, referred to as an engagement position) where it engages with the spline portion 631 of the intermediate member 63 in the front-rear direction, the first transmission member 64 can rotate integrally with the intermediate member 63, that is, power can be transmitted from the first intermediate shaft 41 to the intermediate member 63. In the present embodiment, the diameter of the first spline portion 641 is larger than the diameter of the second spline portion 642. In this way, by forming the first spline section 641 to have a large diameter, efficient torque transmission is possible.

On the other hand, as shown by the broken line in fig. 9, when the first spline section 641 is disposed at a position (hereinafter referred to as a separation position) separated from (not engageable with) the spline section 631, the first transmission member 64 does not transmit (cut) power from the first intermediate shaft 41 to the intermediate member 63.

The diameter of the large diameter portion 417 of the first intermediate shaft 41 is set to be slightly smaller than the inner diameter of the interposed member 63. Therefore, the gap between the inner periphery of the intermediate member 63 and the outer periphery of the large diameter portion 417 of the first intermediate shaft 41 is small. Accordingly, when the first transmission member 64 moves from the disengaged position to the engaged position, the first spline portion 641 and the spline portion 631 can be smoothly engaged with each other. On the other hand, a larger gap is secured between the inner periphery of the interposed member 63 and the outer periphery of the portion other than the large diameter portion 417. Accordingly, when the power transmission from the first intermediate shaft 41 to the intermediate member 63 is interrupted, the co-rotation of the first intermediate shaft 41 and the intermediate member 63 can be more reliably suppressed.

As described above, in the present embodiment, the first transmission member 64 and the interposed member 63 function as the first clutch mechanism 62 that transmits or blocks the power for the hammer operation. In the present embodiment, the first transmission member 64 is connected to the mode switching mechanism 80 (see fig. 12), and moves between the engagement position and the disengagement position in response to the user operating the mode switching dial 800 (see fig. 2). That is, the first clutch mechanism 62 switches between the power transmission state and the cut-off state in response to the operation of the mode switching dial 800. The mode switching mechanism 80 will be described in detail later.

As shown in fig. 8, in the present embodiment, the rotation transmission mechanism 7 includes a drive gear 78 and a driven gear 79. The drive gear 78 is fixed to a front end portion (a portion adjacent to the rear side of the front bearing 421) of the second intermediate shaft 42. The driven gear 79 is fixed to the outer periphery of the cylinder 33 of the main shaft 31 and meshes with the drive gear 78. The drive gear 78 and the driven gear 79 constitute a gear reduction mechanism. As the drive gear 78 rotates integrally with the second counter shaft 42, the main shaft 31 rotates integrally with the driven gear 79. Accordingly, the drill operation is performed in which the tip end tool 91 held by the tool holder 32 is rotationally driven about the driving axis a 1.

Further, as described above, in the present embodiment, the rotational motion of the second driven gear 424 that rotates with the rotation of the motor shaft 25 is transmitted to the second intermediate shaft 42 via the second transmission member 72 and the torque limiter 73. Hereinafter, the torque limiter 73 and the second transmission member 72 will be described in order.

As shown in fig. 6 and 10, the torque limiter 73 is a safety clutch mechanism that is disposed on the second intermediate shaft 42 and is configured to interrupt transmission when the torque acting on the second intermediate shaft 42 exceeds a threshold value. In the present embodiment, the torque limiter 73 includes a driving-side member 74, a driven-side member 75, balls 76, and an urging spring 77.

The drive side member 74 is a cylindrical member that is rotatably supported by the rear half of the second intermediate shaft 42. The second driven gear 424 is rotatably supported by the rear end portion of the driving-side member 74. Therefore, the driving side member 74 is able to rotate about the rotation axis a4 with respect to the second intermediate shaft 42 and the second driven gear 424.

The drive side member 74 includes a cam recess 742 (refer to fig. 11) and a spline portion 743. The cam recess 742 is provided at the front end of the drive-side member 74 and has a cam surface inclined in the circumferential direction. The spline portion 743 is provided on the outer periphery of the drive-side member 74 on the rear side of the cam recess 742, and has a plurality of splines (external teeth) extending in the direction of the rotation axis a4 (front-rear direction).

Driven-side member 75 is a cylindrical member and is disposed around second intermediate shaft 42 on the front side of driving-side member 74. A plurality of grooves 751 extending in the direction of the rotation axis a4 (front-rear direction) are provided in the circumferential direction on the inner periphery of the driven-side member 75. Further, a plurality of grooves 426 extending in the direction of the rotation axis a4 (front-rear direction) are provided in the circumferential direction on the outer periphery of the second intermediate shaft 42. The balls 76 are rollably accommodated in a track defined by the grooves 426 and 751. Accordingly, the driven member 75 is engaged with the second intermediate shaft 42 via the balls 76 in the radial direction and the circumferential direction, and is rotatable integrally with the second intermediate shaft 42. The driven-side member 75 is movable in the front-rear direction with respect to the second intermediate shaft 42 within a range in which the balls 76 can roll in the track.

The driven-side member 75 has a cam protrusion 752 provided at the rear end (see fig. 11). The cam protrusion 752 has a shape substantially matching the cam recess 742 of the driving-side member 74, and has a cam surface inclined in the circumferential direction. The biasing spring 77 is a compression coil spring, and is disposed in a compressed state between the drive gear 78 and the driven member 75. Therefore, the biasing spring 77 always biases the driven member 75 in a direction approaching the driving member 74, that is, in a direction (rearward) in which the cam protrusion 752 meshes with the cam recess 742. When the cam protrusion 752 is engaged with the cam recess 742, torque is transmitted from the driving-side member 74 to the driven-side member 75, and the second intermediate shaft 42 is allowed to rotate. Further, the driving side member 74 and the gear member 423 are urged rearward via the driven side member 75, and are held in the rearmost position relative to the second intermediate shaft 42.

When a load equal to or greater than a threshold value is applied to the second intermediate shaft 42 via the tool holder 32 (main shaft 31) due to the tip tool 91 being locked or the like while the second intermediate shaft 42 is rotating, the engagement between the cam protrusion 752 and the cam recess 742 is released as shown in fig. 11. More specifically, the cam protrusion 752 is disengaged from the cam recess 742 and moved to the front end surface of the driving-side member 74 against the biasing force of the biasing spring 77 by the action of the cam protrusion 752 and the cam surface (inclined surface) of the cam recess 742. That is, the driven-side member 75 moves in a direction (forward) away from the driving-side member 74. At this time, the driven member 75 is guided by the balls 76 rolling between the second intermediate shaft 42 and can smoothly move forward. As a result, torque transmission from driving-side member 74 to driven-side member 75 is interrupted, and rotation of second intermediate shaft 42 is interrupted.

As shown in fig. 6 and 10, the second transmission member 72 is disposed on the second intermediate shaft 42, is configured to be rotatable integrally with the drive-side member 74 of the torque limiter 73, and is movable in the direction of the rotation axis line a4 (front-rear direction) with respect to the drive-side member 74 and the gear member 423.

More specifically, the second transmission member 72 is a substantially cylindrical member disposed around the drive side member 74, and the first spline portion 721 and the second spline portion 722 are provided on the inner periphery of the second transmission member 72. The first spline portion 721 is provided at the front half portion of the second transmission member 72. First spline portion 721 has a plurality of splines (internal teeth) that are constantly engaged with spline portion 743 of drive-side member 74. The second spline portion 722 is provided at the rear end portion of the second transmission member 72 and has a larger inner diameter than the first spline portion 721. The second spline portion 722 has a plurality of splines (internal teeth) that can engage with the spline portion 425 of the gear member 423.

According to this configuration, as shown by a solid line in fig. 10, when the second spline portion 722 is disposed at a position where it engages with the spline portion 425 of the gear member 423 (hereinafter referred to as an engagement position) in the front-rear direction, the second transmission member 72 can rotate integrally with the gear member 423. Therefore, the driving-side member 74 spline-engaged with the second transmission member 72 can also rotate integrally with the gear member 423. On the other hand, as shown by the broken line in fig. 10, when the second spline portion 722 is disposed at a position (hereinafter referred to as a separation position) where it is separated from (cannot be engaged with) the spline portion 425, the second transmission member 72 cannot transmit (cut off) power from the gear member 423 to the drive-side member 74.

As described above, in the present embodiment, the second transmission member 72 and the gear member 423 function as the second clutch mechanism 71 that transmits or cuts off the power for the drill operation. In the present embodiment, the second transmission member 72 is connected to the mode switching mechanism 80 (see fig. 12) as in the case of the first transmission member 64, and moves between the engagement position and the disengagement position in response to the user's operation of the mode switching dial 800 (see fig. 2). That is, the second clutch mechanism 71 is also switched between the power transmission state and the cut-off state in response to the operation of the mode switching dial 800, as in the case of the first clutch mechanism 62.

The mode switching dial 800 and the mode switching mechanism 80 will be described below.

As shown in fig. 12 to 14, the mode switching mechanism 80 is configured to switch the operation mode of the hammer drill 101 in conjunction with the mode switching dial 800. In the present embodiment, the hammer drill 101 has three operation modes, i.e., a hammer drill mode, a hammer mode, and a drill mode. The hammer drill mode is an operation mode in which both the impact mechanism 6 and the rotation transmission mechanism 7 are driven to perform a hammer operation and a drill operation. The hammer mode is an operation mode in which the power transmission for the drill operation is cut off by the second clutch mechanism 71 and only the impact mechanism 6 is driven, thereby performing only the hammer operation. The drill mode is an operation mode in which only the drill operation is performed by cutting off the power transmission for the hammer operation by the first clutch mechanism 62 and driving only the rotation transmission mechanism 7.

As shown in fig. 2 and 12 to 14, a mode switching dial 800 is provided at a lower end portion of the main body housing 10 (specifically, the front housing 13) so as to be externally operable by a user. The mode switching dial 800 includes a disk-shaped operation portion 801 having a knob, and a first pin 803 and a second pin 805 protruding from the operation portion 801.

The operation portion 801 is held by the main body case 10 so as to be rotatable about a rotation axis extending in the vertical direction. A part of the operation portion 801 is partially exposed to the outside through an opening formed in the lower wall of the main body case 10 (front case 13), and can be rotated by the user. In addition, the mode switching dial 800 defines rotational positions corresponding to the hammer drill mode, the hammer mode, and the drill mode, respectively. The user can set the operation mode by disposing the mode switching dial 800 at a rotational position corresponding to a desired operation mode. The first pin 803 and the second pin 805 protrude upward from the upper surface of the operation portion 801. The first pin 803 and the second pin 805 move on a circle centered on the rotational axis of the operation portion 801 as the mode switching dial 800 rotates.

The mode switching mechanism 80 includes a first switching member 81, a second switching member 82, a first spring 83, and a second spring 84.

The first switching member 81 has a pair of support holes (not shown) and is supported by a support shaft 88 inserted through the support holes so as to be movable in the front-rear direction. The support shaft 88 is a shaft fixed to the bearing support 15 and protruding forward from the bearing support 15. The support shaft 88 extends in parallel with the first intermediate shaft 41 and the second intermediate shaft 42. A retainer ring 881 is fixed to a central portion of the support shaft 88 in the axial direction. The first switching member 81 is supported on the front side of the retainer 881. The second switching member 82 has a pair of support holes (not shown), and is supported by a support shaft 88 inserted through the support holes so as to be movable in the front-rear direction on the rear side of the retainer 881.

The first switching member 81 and the second switching member 82 are engaged with the first transmission member 64 and the second transmission member 72, respectively. In more detail, annular grooves 645 and 725 are provided on the outer peripheries of the first transmission member 64 and the second transmission member 72, respectively. The first switching member 81 is engaged with the first transmission member 64 via a plate-like first engaging portion 813 (see fig. 14) disposed in the groove 645. Similarly, the second switching member 82 is engaged with the second transmission member 72 via a plate-like second engagement portion 823 (see fig. 10) disposed in the groove 725. Further, the first transmission member 64 and the second transmission member 72 are rotatable with respect to the first switching member 81 and the second switching member 82, respectively, in a state where the first engagement portion 813 and the second engagement portion 823 are engaged with the grooves 645 and 725, respectively.

The first spring 83 is a compression coil spring, is disposed in a compressed state between the front housing 13 and the first switching member 81, and constantly biases the first switching member 81 rearward. Accordingly, the first transmission member 64 engaged with the first switching member 81 is also always biased to the rearward engagement position. The second spring 84 is a compression coil spring, is disposed in a compressed state between the retainer 881 fixed to the support shaft 88 and the second switching member 82, and constantly biases the second switching member 82 rearward. Accordingly, the second transmission member 72 engaged with the second switching member 82 is also always biased to the rearward engagement position. The rearmost position of the first switching member 81 is a position where the first switching member 81 abuts against the stopper 881. The rearmost position of the second switching member 82 is a position where the second switching member 82 abuts against the front surface of the bearing support body 15.

When the mode switching dial 800 is disposed at a rotational position (hereinafter referred to as a hammer drill position) corresponding to the hammer drill mode shown in fig. 12, the first pin 803 is disposed at a position adjacent to the rear of the first switching member 81 disposed at the rearmost position, and the second pin 805 is disposed at a position adjacent to the rear of the second switching member 82 disposed at the rearmost position. At this time, the first transmission member 64 is disposed at an engagement position (see fig. 9) where the second spline portion 642 engages with the spline portion 631 of the intermediate member 63, and the first clutch mechanism 62 is in a power transmission state. The second transmission member 72 is disposed at an engagement position (see fig. 10) where the second spline portion 722 engages with the spline portion 425 of the gear member 423, and the second clutch mechanism 71 is also in a power transmission state.

When the motor 2 is energized, power is transmitted from the motor shaft 25 to the impact mechanism 6 via the first intermediate shaft 41, and the hammer action is performed. At the same time, power is transmitted from the motor shaft 25 to the rotation transmission mechanism 7 via the second intermediate shaft 42, and the drill operation is also performed.

When the mode switching dial 800 is rotationally operated from the hammer drill position shown in fig. 12 to a rotational position (hereinafter referred to as a hammer position) corresponding to the hammer mode shown in fig. 13, the second pin 805 moves clockwise while abutting against the second switching member 82 from behind, and moves the second switching member 82 forward against the biasing force of the second spring 84. When the mode switching dial 800 is disposed at the hammer position, the second switching member 82 is disposed at the foremost position. As the second switching member 82 moves, the second transmission member 72 moves from the engagement position to the disengagement position (see fig. 10), and the second clutch mechanism 71 is switched to the disengaged state.

On the other hand, the first pin 803 moves in the clockwise direction in a bottom view without interfering with the first switching member 81 and the second switching member 82, and is disposed at a position away from the first switching member 81 and the second switching member 82. Therefore, during this time, the first switching member 81 and the first transmitting member 64 do not move, and the first clutch mechanism 62 maintains the power transmitting state unchanged.

Even if the motor 2 is energized, no power is transmitted from the motor shaft 25 to the second intermediate shaft 42, and therefore, the drilling operation is not performed. On the other hand, since power is transmitted from the motor shaft 25 to the impact mechanism 6 via the first intermediate shaft 41, only the hammer action is performed.

When the mode switching dial 800 is rotationally operated from the hammer drill position shown in fig. 12 to a rotational position (hereinafter referred to as a drill position) corresponding to the drill mode shown in fig. 14, the first pin 803 abuts against the first switching member 81 from behind, and moves counterclockwise about the rotational axis of the operation portion 801 in a bottom view, while moving the first switching member 81 forward against the urging force of the first spring 83. When the mode switching dial 800 is disposed at the drill position, the first switching member 81 is disposed at the forefront position. As the first switching member 81 moves, the first transmission member 64 moves from the engagement position to the disengagement position (see fig. 9), and the first clutch mechanism 62 is switched to the disengagement state.

On the other hand, the second pin 805 does not interfere with the first switching member 81 nor with the second switching member 82, and is disposed adjacent to the second switching member 82 while moving counterclockwise about the rotational axis of the operating portion 801 in a bottom view. Therefore, during this time, the second switching member 82 and the second transmission member 72 do not move, and the second clutch mechanism 71 maintains the power transmission state.

Even if the motor 2 is energized, no power is transmitted from the first intermediate shaft 41 to the motion conversion member 61, and therefore, the hammer action is not performed. On the other hand, since power is transmitted from the motor shaft 25 to the rotation transmission mechanism 7 via the second intermediate shaft 42, only the drill operation is executed.

As described above, the hammer drill 101 of the present embodiment has two independent intermediate shafts (the first intermediate shaft 41 and the second intermediate shaft 42) that extend parallel to the drive axis a1 and that respectively transmit power for the hammer action and the drill action. Therefore, the first intermediate shaft 41 and the second intermediate shaft 42 can be shortened as compared with the case where a single common intermediate shaft is used for power transmission for the hammer action and the drill action. This makes it possible to shorten the entire hammer drill 101 in the drive axis direction. Further, by shortening the first intermediate shaft 41 and the second intermediate shaft 42, the center of gravity of the hammer drill 101 can be brought close to the hand grip 17 coupled to the rear end portion of the main body case 10, and operability can be improved.

Also, the first intermediate shaft 41 and the second intermediate shaft 42 are specialized for power transmission for hammer action and power transmission for drill action, respectively. That is, the power transmission path dedicated to the hammer action and the power transmission path dedicated to the drill action are not provided in series but in parallel. Therefore, the power transmission from the first intermediate shaft 41 to the impact mechanism 6 and the power transmission from the second intermediate shaft 42 to the rotation transmission mechanism 7 can be optimized, and the power transmission to the main shaft 31 as the final output shaft can be optimized.

Further, since the motion conversion member 61 is mounted on the first intermediate shaft 41 dedicated to the hammer operation, it is necessary to have a certain length. In contrast, the drive gear 78 mounted on the second intermediate shaft 42 dedicated to the drilling operation does not need to have such a long length. Therefore, in the present embodiment, the torque limiter 73 is disposed so as to effectively utilize the space generated in the second intermediate shaft 42. The second intermediate shaft 42 has a lower transmission torque than the main shaft 31 as the final output shaft. Therefore, the torque limiter 73 can be smaller and lighter than the torque limiter mounted on the main shaft 31. Further, in the torque limiter 73 of the present embodiment, when the torque limiter 73 is operated, the driven-side member 75 can be guided in the direction of the rotation axis a4 while the balls 76 roll. This reduces friction between the driven member 75 and the second intermediate shaft 42, thereby stabilizing the operating torque.

In the present embodiment, the first clutch mechanism 62 and the second clutch mechanism 71 are provided on the first intermediate shaft 41 and the second intermediate shaft 42, respectively. Therefore, the power for the hammer action and the power for the drill action can be cut off separately as needed. Also, the first clutch mechanism 62 and the second clutch mechanism 71 are each switched between the power transmission state and the cut-off state in response to an operation of the same operation member (mode switching dial 800). Therefore, the user can operate the first clutch mechanism 62 and the second clutch mechanism 71 by operating the mode switching dial 800 to switch the operation mode in accordance with a desired operation.

As shown in fig. 6 and 12 to 14, the hammer drill 101 is provided with a lock plate 45, and the lock plate 45 is configured to restrict rotation of the second intermediate shaft 42 in the hammer mode. This is to prevent the tip end tool 91 held to the tool holder 32 from freely rotating during the hammer action.

The lock plate 45 is configured to engage with the second transmission member 72 disposed at the separated position, and to restrict the rotation of the second transmission member 72. The lock plate 45 is a metal elongated member. The lock plate 45 is held slidably in the front-rear direction by a rib 137 (only a part of which is shown in fig. 5 and 19 to 21) provided in the front housing 13 in a state biased rearward by the biasing spring 46. The biasing spring 46 is a compression coil spring, and the tip end portion thereof is disposed in a recess 138 (see fig. 19 to 21) provided in the front housing 13.

The lock plate 45 includes a spring receiving portion 451, an abutting portion 453, and an engaging portion 455. The spring receiving portion 451 is a projection provided at the front end portion of the lock plate 45, and is inserted into the rear end portion of the biasing spring 46. The abutment portion 453 extends rearward along the inner peripheral surface of the front housing 13 on the radially outer side of the torque limiter 73 and the second transmission member 72. The lock plate 45 is biased rearward by the biasing spring 46, and the rear end surface of the abutting portion 453 is held at a position (initial position) abutting against the front end surface of the projection 157 projecting forward from the front surface of the bearing support 15. The locking portion 455 is a substantially rectangular portion disposed on the front side of the second transmission member 72. On the other hand, a plurality of concave portions 727 are provided at the distal end portion of the second transmission member 72. The concave portions 727 are substantially rectangular concave portions recessed rearward from the front end of the second transmission member 72, and are provided at equal intervals in the circumferential direction.

As described above, the second transmission member 72 is disposed at the engagement position in the hammer mode and the drill mode. At this time, as shown in fig. 12 and 14, the locking portion 455 of the lock plate 45 is positioned at a position away forward from the second transmission member 72. Therefore, the second transmission member 72 can rotate together with the first driven gear 414 without being interfered by the lock plate 45.

On the other hand, as shown in fig. 13, in the hammer mode, the second transmission member 72 is disposed at the spaced position forward of the engaged position, and the locking portion 455 of the lock plate 45 is engaged with one of the plurality of concave portions 727 of the second transmission member 72. Accordingly, since the rotation of the second transmission member 72 is restricted, the rotation of the driving-side member 74, the driven-side member 75, and the second intermediate shaft 42 is also restricted. Further, the rotation of the main shaft 31 via the drive gear 78 and the driven gear 79 is also restricted.

Further, when the locking portion 455 does not face the recess 727 in the process of moving the second transmission member 72 from the engagement position to the disengagement position, the front end surface of the second transmission member 72 abuts against the locking portion 455, and the lock plate 45 is moved forward against the biasing force of the biasing spring 46. Then, when the tip tool 91 is rotated and the second transmission member 72 is rotated to a position where the locking portion 455 faces the recess 727 via the spindle 31 and the second intermediate shaft 42, the lock plate 45 is urged by the urging spring 46 to move rearward, and the locking portion 455 engages with the recess 727.

In the present embodiment, the hammer drill 101 is configured to suppress transmission of vibration (particularly, vibration in the drive axis direction (front-rear direction)) generated as the drive mechanism 5 is driven to the body case 10 and the handle 17. Hereinafter, a vibration-proof structure of the hammer drill 101 will be described.

In the present embodiment, as shown in fig. 2, the main shaft 31 and the impact mechanism 6 (specifically, the motion conversion member 61, the piston 65, the hammer 67, and the impact bolt 68) are disposed inside the main body case 10 so as to be movable in the drive axis direction (front-rear direction) with respect to the main body case 10. More specifically, the movable support 18 is disposed inside the main body case 10, and the movable support 18 is movable in the front-rear direction with respect to the main body case 10 in a state of being biased forward with respect to the main body case 10. The main shaft 31 and the impact mechanism 6 are supported by the movable support 18 and are movable integrally with the movable support 18 relative to the main body case 10.

As shown in fig. 5, 7, 15, and 16, the movable support 18 includes a spindle support portion 185, a rotor support portion 187, a first shaft insertion portion 181, and a second shaft insertion portion 182. In the present embodiment, the movable support 18 is formed as a single member made of metal.

The spindle support portion 185 is formed in a substantially cylindrical shape and configured to support a portion of the spindle 31. A bearing 317 is held inside the spindle support 185. The spindle support portion 185 supports the rear portion of the cylinder 33 via a bearing 317 so as to be rotatable about a drive axis a 1. Further, as described above, the main shaft 31 is supported by the bearing 316 and the bearing 317 so as to be rotatable about the drive axis a1 with respect to the main body case 10. The other bearing 316 is held in the cylinder 131, and supports the rear portion of the tool holder 32 so as to be rotatable about the drive axis a1 and movable in the front-rear direction.

The rotor support portion 187 is a portion formed in a substantially cylindrical shape, and is connected to a lower portion of the right end portion of the spindle support portion 185. A bearing 614 is fixed to the rotor support 187 by a screw. The rotating body support portion 187 supports the rotating body 611 via the bearing 614 so as to be rotatable about the rotation axis a 3.

As described above, by supporting the main shaft 31 and the rotating body 611 by the movable support 18, the swing member 616 attached to the rotating body 611, the piston 65 disposed in the main shaft 31, the hammer 67, and the impact bolt 68 are also supported by the movable support 18. Therefore, the movable support 18, the main shaft 31, and the impact mechanism 6 constitute a movable unit 180 as a component that is integrally movable in the front-rear direction with respect to the main body case 10.

The first shaft insertion portion 181 and the second shaft insertion portion 182 are disposed on the right and left sides of the spindle support portion 185, respectively, symmetrically with respect to the reference plane VP. The first shaft insertion portion 181 has a pair of cylindrical portions 183. The pair of cylindrical portions 183 are provided on the same shaft so as to be separated in the front-rear direction. A bearing 184 is fitted into each cylindrical portion 183. In the present embodiment, a cylindrical oilless bearing is used as the bearing 184. The second shaft insertion portion 182 has the same structure as the first shaft insertion portion 181. That is, the second shaft insertion portion 182 has a pair of cylindrical portions 183 to which bearings 184 are fixed.

As shown in fig. 5 and 15, the movable support 18 (movable unit 180) is supported by the main body case 10 by the first guide shaft 191 and the second guide shaft 192 so as to be movable in the front-rear direction with respect to the main body case 10. The first guide rail 191 and the second guide rail 192 are disposed symmetrically with respect to the reference plane VP, and extend parallel to the drive axis a1 (in the front-rear direction) in the upper portion of the front housing 13. The first guide shaft 191 and the second guide shaft 192 have their respective front end portions fixedly held by the front housing 13 and their rear end portions fixedly held by the bearing support 15. Therefore, the first and second guide shafts 191 and 192 cannot move relative to the main body housing 10.

In the present embodiment, the first guide shaft 191 and the second guide shaft 192 are each formed of iron (or an alloy containing iron as a main component). The first guide shaft 191 and the second guide shaft 192 are slidably inserted through a pair of front and rear bearings 184 of the first shaft insertion portion 181 and the second shaft insertion portion 182, respectively. That is, the inner peripheral surface of the bearing 184 defines the support holes 190 of the first guide shaft 191 and the second guide shaft 192. With such a configuration, the movable support 18 (movable unit 180) can be moved in the front-rear direction with respect to the main body housing 10 while being guided by the first guide shaft 191 and the second guide shaft 192.

In addition, as described above, the first intermediate shaft 41 for hammer action and the second intermediate shaft 42 for drill action are supported by the bearings 411 and 421 held in the front housing 13 and the bearings 412 and 422 held in the bearing support body 15, respectively, so as not to be movable in the front-rear direction with respect to the main body housing 10. Therefore, the movable support 18 (movable unit 180) is also movable in the front-rear direction with respect to the first intermediate shaft 41 and the second intermediate shaft 42.

In the present embodiment, the movable support 18 supports the main shaft 31 and the impact mechanism 6 and receives a load during the hammer operation, and therefore is formed of an aluminum alloy or a magnesium alloy in order to achieve both strength and weight reduction. On the other hand, the bearing 184 that slides on the first guide shaft 191 and the second guide shaft 192 is formed of a material that is more excellent in lubrication than the movable support 18. Further, the portions of the movable support 18 that define the support holes 190 of the first guide shaft 191 and the second guide shaft 192 (i.e., the portions that slide on the first guide shaft 191 and the second guide shaft 192) need not be the bearings 184. For example, only the cylindrical portion defining the support hole 190 may be formed integrally with the other portion of the movable support 18, and may be made of a material different from the other portion (for example, iron or an alloy containing iron as a main component).

A first biasing spring 194 and a second biasing spring 195 are disposed behind the first shaft insertion portion 181 and the second shaft insertion portion 182, respectively. The first urging spring 194 and the second urging spring 195 are both compression coil springs, are externally fitted to the first guide shaft 191 and the second guide shaft 192, respectively, and are disposed in a compressed state between the movable support 18 and the bearing support 15. More specifically, the front end of the first biasing spring 194 abuts against the rear end of the cylindrical portion 183 on the rear side of the first through hole 181 via a washer. The rear end of the first biasing spring 194 is fitted into a spring receiving portion provided on the front surface of the bearing support body 15. Similarly, the front end of the second biasing spring 195 abuts against the rear end of the cylindrical portion 183 on the rear side of the second shaft insertion portion 182 via a washer. The rear end of the second biasing spring 195 is fitted into a spring receiving portion provided on the front surface of the bearing support body 15.

With such a configuration, the first biasing spring 194 and the second biasing spring 195 always bias the movable support 18 (movable unit 180) forward. Therefore, when no external force is applied to the movable support 18 (movable unit 180) in the rearward direction, the first shaft insertion portion 181 and the front cylindrical portion 183 of the second shaft insertion portion 182 are held at the foremost position (initial position) in contact with the shoulder portion 133 provided in the front housing 13 in the movable support 18. That is, the shoulder 133 functions as a stopper that prevents the movable support 18 (movable unit 180) from further moving forward.

On the other hand, as shown in fig. 5 and 17, a pair of left and right cushion members 197 are provided on the front surface side of the bearing support portion 15 as stoppers for restricting further rearward movement of the movable support portion 18 (movable unit 180). More specifically, a pair of left and right cylindrical protrusions 155 are provided on the front surface of the bearing support body 15 symmetrically with respect to the reference plane VP. The projection 155 projects forward so as to face the upper end portion of the movable support 18 (specifically, a portion adjacent to the first shaft insertion portion 181 and the second shaft insertion portion 182 on the reference plane VP side). Each cushion member 197 is made of cylindrical rubber and fitted to each projection 155.

The cushion member 197 protrudes forward from the front end of the protrusion 155 in a state where no external force is applied. When the movable support 18 (movable unit 180) is located at the foremost position (position in fig. 17), the buffer member 197 is located at a position rearward away from the movable support 18. The buffer member 197 is configured to come into contact with the movable support 18 from the rear when the movable support 18 (the movable unit 180) moves rearward relative to the main body case 10 and the first biasing spring 194 and the second biasing spring 195 (see fig. 15) are compressed by a predetermined amount.

In addition, in the present embodiment, the first guide shaft 191 and the second guide shaft 192 as shown in fig. 5 and 15 each have a circular cross section but have different diameters. More specifically, the diameter of the second guide shaft 192 on the left side is slightly smaller than the diameter of the first guide shaft 191 on the right side with respect to the reference plane VP. On the other hand, the total of four cylindrical portions 183 and the bearings 184 of the first and second shaft insertion portions 181 and 182 have the same configuration. That is, the diameter of the support hole 190 of the first guide shaft 191 is the same as the diameter of the support hole 190 of the second guide shaft 192.

Therefore, the clearance formed between the outer peripheral surface of the second guide shaft 192 positioned on the left side with respect to the reference plane VP and the inner peripheral surfaces of the pair of bearings 184 of the second shaft insertion portion 182 is slightly larger than the clearance formed between the outer peripheral surface of the first guide shaft 191 positioned on the right side with respect to the reference plane VP and the inner peripheral surfaces of the pair of bearings 184 of the first shaft insertion portion 181. That is, the distance from the second guide shaft 192 is slightly larger than the distance from the first guide shaft 191. The first guide shaft 191 and the bearing 184 of the first shaft insertion portion 181 are set to have higher dimensional accuracy, and the first guide shaft 191 and the bearing 184 of the first shaft insertion portion 181 are configured to be fitted with each other with almost no gap.

When it is desired to fit both the first guide shaft 191 and the second guide shaft 192 into the respective support holes 190 with as little clearance as possible, assembly may become difficult due to errors in the first guide shaft 191, the second guide shaft 192, and/or the respective support holes 190. In contrast, according to the configuration of the present embodiment as described above, by forming the gap between the first guide shaft 191 and the bearing 184 with high accuracy, the guide function of the movable support 18 can be maintained well, and the assembly can be facilitated.

Further, the guide shaft (hereinafter referred to as a reference guide shaft) corresponding to a smaller pitch (higher dimensional accuracy) of the first guide shaft 191 and the second guide shaft 192 is preferably determined in consideration of an influence on the engagement of the drive gear 78 and the driven gear 79 (see fig. 8) when the movable unit 180 rotates. More specifically, assuming that the movable unit 180 turns by the same angle about the respective axes of the first guide shaft 191 and the second guide shaft 192, it is preferable to select a guide shaft that makes the change in the center distance of the drive axis a1 of the main shaft 31 and the rotation axis a4 of the second intermediate shaft 42 (the shortest distance between the drive axis a1 and the rotation axis a4) smaller. This is because when the movable unit 180 rotates, it is difficult to affect the engagement between the drive gear 78 and the driven gear 79.

Hereinafter, a method of determining the reference guide axis will be specifically described with reference to fig. 18. Fig. 18 shows common tangents T of the pitch circles C1 and C2 and the pitch circles C1 and C2 of the drive gear 78 and the driven gear 79 (refer to fig. 8) on a plane orthogonal to the drive axis a1 and the rotation axis a4, respectively, when the drive gear 78 and the driven gear 79 are in a proper meshed state. Further, the point P is a point on the driven gear 79, and at this time, the point P coincides with a node point of the drive gear 78 and the driven gear 79.

As described above, the drive gear 78 is provided on the second intermediate shaft 42 that is not movable in the axial direction and the radial direction with respect to the main body case 10. On the other hand, the driven gear 79 provided on the main shaft 31 is a part of the movable unit 180. Therefore, the driven gear 79 moves relative to the drive gear 78 about the axis of the reference guide shaft in accordance with the rotation of the movable unit 180. At this time, when the point P on the driven gear 79 moves in the extending direction of the common tangent T with respect to the drive gear 78, the change in the center distance is small, and the meshing is less likely to be affected. On the contrary, when the point P moves in a direction substantially orthogonal to the common tangent T, the center distance changes greatly as the amount of movement thereof increases, and the engagement may be released or may become too deep.

As described above, as indicated by reference symbol S in fig. 18, the reference guide shaft is preferably disposed on the opposite side of the drive gear 78 on a straight line L passing through the rotation axis a4 of the drive gear 78 and the drive axis a1 as the rotation axis of the driven gear 79. In addition, in the case where neither the first guide shaft 191 nor the second guide shaft 192 is on the straight line L, it is preferable to use one of the first guide shaft 191 and the second guide shaft 192, which is closer to the straight line L, as the reference guide shaft. Specifically, an angle α formed by a line segment connecting the axis of the first guide shaft 191 and the drive axis a1 and a straight line L and an angle β formed by a line segment connecting the axis of the second guide shaft 192 and the drive axis a1 and the straight line L are compared on a plane orthogonal to the drive axis a1 and the rotation axis a 4. A guide axis corresponding to the smaller one of the angle α and the angle β may be set as the reference axis.

In the present embodiment, the drive axis a1 and the first and second guide rails 191 and 192 are arranged on a straight line on a plane orthogonal to the drive axis a1 and the rotation axis a 4. Therefore, the angle α 1 and the angle β 1 are the same. Therefore, the change in the center distance when the movable unit 180 rotates is the same regardless of which of the first guide shaft 191 and the second guide shaft 192 is determined as the reference guide shaft. Therefore, the second guide shaft 192 may be used as the reference shaft instead of the first guide shaft 191. On the other hand, for example, when the positions of the first guide shaft 191 and the second guide shaft 192 are changed to the positions indicated by the broken lines in fig. 18, the angle α 2 is smaller than the angle β 2. Therefore, in this case, the first guide shaft 191 is preferably used as the reference guide shaft.

Further, in the present embodiment, the first guide shaft 191 and the second guide shaft 192 have different diameters from each other, but the first guide shaft 191 and the second guide shaft 192 may have the same diameter. In this case, the clearances (pitches) corresponding to the first guide shaft 191 and the second guide shaft 192 can be made different by making the inner diameters of the pair of bearings 184 of the first shaft insertion portion 181 different from the inner diameters of the pair of bearings 184 of the second shaft insertion portion 182. Alternatively, the first and second guide shafts 191 and 192 may have different diameters from each other, and the pair of bearings 184 of the first and second shaft insertion parts 181 and 182 and the pair of bearings 184 may have different inner diameters from each other.

In addition, in the present embodiment, a method of facilitating the assembly of the lock plate 45 is employed when assembling the internal structure to the front housing 13. Hereinafter, a method of assembling the lock plate 45 will be described with reference to fig. 19 to 21. In the present embodiment, the front housing 13 including the cylinder portion 131 is configured as a single cylindrical member. Further, the lock plate 45 is positioned at the initial position by fitting the bearing support body 15 into the rear end portion of the front housing 13. Therefore, after the biasing spring 46 is fitted into the recess 138, the locking plate 45 and the biasing spring 46 may be disengaged when the opening at the rear end of the front housing 13 is directed downward before the worker fits into the bearing support 15 by merely inserting the spring support portion 451 into the biasing spring 46 and engaging the locking plate 45 with the rib 137.

Therefore, in the present embodiment, as shown in fig. 19, first, the spring support portion 451 is fixed by press fitting into the rear end portion of the biasing spring 46. The lock plate 45 is fitted forward along the rib 137, and the front end portion of the biasing spring 46 is fixed by press-fitting into the recess 138 of the front housing 13. Accordingly, the lock plate 45 is temporarily fixed to the front housing 13 by the biasing spring 46. Therefore, even if the operator moves the rear end of the front housing 13 downward, the lock plate 45 and the biasing spring 46 do not fall off.

As shown in fig. 20, the operator inserts the first guide shaft 191 and the second guide shaft 192 into the first shaft insertion portion 181 and the second shaft insertion portion 182, respectively, to support the movable unit 180. The operator fits the distal ends of the first guide shaft 191 and the second guide shaft 192 into a recess provided in the front housing 13 (see fig. 15), and fits the bearing support body 15 into the rear end of the front housing 13 while compressing the O-ring 151.

In this process, the abutting portion 453 of the lock plate 45 abuts against the projection 157 of the bearing support body 15. At this time, the urging spring 46 is in an uncompressed state. After that, the bearing support body 15 presses the lock plate 45 via the projection 157, compresses the biasing spring 46, and moves the biasing spring 46 forward along the rib 137. When the bearing support body 15 reaches the predetermined position shown in fig. 21, the assembly of the lock plate 45 is completed. In this way, the worker can easily assemble the lock plate 45 to the front housing 13 and the bearing support 15.

Further, the method of temporarily fixing the lock plate 45 is not limited to the above method. Although not shown in detail, the lock plate 45 may be configured to hold the biasing spring 46 in a compressed state, for example. The lock plate 45 may be temporarily fixed to the front housing 13 by pressing and fixing the distal end portion of the biasing spring 46 to a locking piece provided on the front housing 13.

Further, for example, the locking plate 45 may be temporarily fixed using a rubber pin. In this case, a holding recess for a rubber pin is provided inside the rear end portion of the front housing 13. The holding recess is provided to abut the rubber pin against the rear end of the lock plate 45 at a position rearward of the initial position. The operator fits the front end portion of the biasing spring 46 into the recess 138, and further fits the spring support portion 451 of the lock plate 45 into the rear end portion of the biasing spring 46. After that, the locking plate 45 is temporarily fixed by fitting the rubber pin into the holding recess. When the bearing support body 15 is fitted to a predetermined position of the front housing 13, the lock plate 45 is pressed forward from the position where it abuts against the rubber pin, and is disposed at the initial position.

The operation of the hammer drill 101 according to the present embodiment will be described below.

When the user presses the operation trigger 171 to turn on the switch 172, the motor 2 is energized to drive the drive mechanism 5. In more detail, as described above, the impact mechanism 6 and/or the rotation transmission mechanism 7 are driven to perform the hammer action and/or the drill action in response to the action mode set via the mode switching dial 800.

In the hammer drill mode and the hammer mode in which the hammer is operated, when the tip tool 91 is pressed against a workpiece to perform a machining operation, vibration in the driving axis direction (the front-rear direction) is mainly generated in the impact mechanism 6 due to a force of the impact mechanism 6 driving the tip tool 91 and a reaction force from the workpiece of an impact force of the tip tool 91. By this vibration, the movable unit 180 moves in the front-rear direction along the first guide shaft 191 and the second guide shaft 192 with respect to the main body housing 10, and the first urging spring 194 and the second urging spring 195 expand and contract (elastically deform). Accordingly, the vibration of the movable unit 180 is absorbed, thereby reducing the vibration transmitted to the main body case 10 and the handle 17.

When the movable unit 180 moves rearward due to vibration and the first biasing spring 194 and the second biasing spring 195 are compressed by a predetermined amount, the buffer member 197 held by the bearing support portion 15 collides with the movable support portion 18, and further rearward movement of the movable unit 180 is restricted. Accordingly, collision of the bearing support 15 with the movable support 18 is prevented. Since the cushion member 197 is made of rubber, the impact caused by the collision between the movable support 18 and the cushion member 197 is reduced by elastic deformation of the rubber.

During the machining operation, the user continuously presses the handle 17 and the main body case 10 forward toward the workpiece in order to maintain the state in which the tip end tool 91 is pressed against the workpiece. Therefore, the movable unit 180 tends to be maintained in a state of being disposed at a position rearward of the foremost position shown in fig. 15. Therefore, in the present embodiment, no buffer member is disposed on the shoulder 133 for restricting the forward movement of the movable support 18. However, a buffer member similar to the buffer member 197 may be disposed on the shoulder 133.

As shown in fig. 9, in the hammer drill mode and the hammer mode, the first transmission member 64 is disposed at the engagement position (position indicated by a solid line), is spline-engaged with the intermediate member 63, and transmits the rotation of the first intermediate shaft 41 to the intermediate member 63. The rotating body 611 as a part of the movable unit 180 is movable with respect to the main body case 10 in a range between a most forward position shown by a solid line and a most rearward position shown by a broken line as it vibrates. As described above, the rotating body 611 is spline-engaged with the intermediate member 63 held immovably in the front-rear direction. Therefore, the rotating body 611 moves in the front-rear direction along the splines with respect to the intermediate member 63 while rotating integrally with the intermediate member 63. In contrast, since the intermediate member 63 and the first transmission member 64 do not move relative to each other in the front-rear direction, the engagement state between the intermediate member 63 and the first transmission member 64 is not affected by the relative movement of the movable unit 180 in the front-rear direction. Therefore, the power transmission state from the first intermediate shaft 41 to the motion conversion member 61 (specifically, the rotating body 611) can be stably maintained.

In the hammer drill mode in which the drill operation is performed in addition to the hammer operation, the main shaft 31 as a part of the movable unit 180 also moves in the front-rear direction with respect to the main body case 10 in accordance with the vibration. Therefore, as shown in fig. 10, the driven gear 79 provided on the outer periphery of the cylinder 33 is movable in the front-rear direction with respect to the drive gear 78 between a position shown by a solid line and a position shown by a broken line, in which the drive gear 78 is not movable in the front-rear direction with respect to the main body case 10. In contrast, in the present embodiment, the length of the drive gear 78 in the front-rear direction is set so as to cover the movement range of the driven gear 79. Therefore, the driven gear 79 is also always meshed with the drive gear 78 and rotates during the movement of the main shaft 31.

Even in the drill mode in which only the drill operation is performed, when the movable unit 180 moves in the front-rear direction with respect to the main body case 10, as described above, the vibration transmitted to the main body case 10 and the handle 17 is reduced by the expansion and contraction of the first and second urging springs 194 and 195. Further, similarly to the hammer drill mode, the rotation is transmitted from the second counter shaft 42 to the main shaft 31 via the drive gear 78 and the driven gear 79 without being affected by the relative movement of the movable unit 180 in the forward and backward direction.

Further, in the hammer drill mode and the drill mode in which the drill action is performed, when a load of a threshold value or more is applied to the second intermediate shaft 42 during the drill action, as described above, the torque limiter 73 operates to cut off the torque transmission in the power transmission path dedicated to the drill action, thereby stopping the drill action.

In the hammer drill mode and the hammer mode in which the hammer operation is performed, it is preferable that the hammer 67 does not strike the impact bolt 68 when the tip tool 91 is not attached to the tool holder 32 or when the tip tool 91 is not pressed against the workpiece, that is, when a load is not applied (hereinafter, referred to as an unloaded state). Therefore, the hammer drill 101 of the present embodiment is provided with the idle running prevention mechanism 30 to promptly stop the impact of the hammer 67 on the impact bolt 68 when in the unloaded state. The air-hammer prevention mechanism 30 will be explained below.

The air-crash prevention mechanism 30 of the present embodiment is a mechanism configured as follows: when the reciprocation of the piston 65 continues in the idling state, the displacement timing of the striker 68 is shifted to catch the hammer 67. First, the detailed structure of the hammer 67 and the impact bolt 68 will be described.

As shown in fig. 7, the hammer 67 includes a cylindrical main body 671 and a small diameter portion 672 having a diameter smaller than that of the main body 671 and protruding forward from the main body 671. The body portion 671 has a diameter substantially equal to the inner diameter of the piston 65. An O-ring for hermetically sealing between the ram 67 and the piston 65 is attached to an outer peripheral portion of the body portion 671. A flange portion 673 is provided at the tip of the small diameter portion 672. The impact bolt 68 is configured as a cylindrical member having a large diameter portion 681, and small diameter portions 683 and 684, wherein the large diameter portion 681 is provided at a substantially central portion in the axial direction, and the small diameter portions 683 and 684 are provided at the front side and the rear side of the large diameter portion 681, respectively.

On the other hand, as shown in fig. 22, the runaway prevention mechanism 30 includes a catcher 34 disposed inside the cylinder 33, a tool holder 32, a restricting ring 35 disposed inside the tool holder 32, a guide sleeve 36, and a cushion ring 37.

The catcher 34 is configured to catch and hold the hammer 67 in an unloaded state. The catcher 34 includes a catching ring 341 and a ring holding part 343. The ring holder 343 is a metal cylindrical member, and is fitted into the front end of the cylinder 33 and held slidably in the front-rear direction. However, the final position of the catcher 34 is defined by a retainer ring 345 fixed inside the cylinder 33. The catching ring 341 is an O-ring and is fitted into the rear end portion of the ring holder 343. The catch ring 341 of the present embodiment is made of rubber.

In the present embodiment, the tool holder 32 is formed in a stepped cylindrical shape. The inner diameter of the tool holder 32 is smallest at the front portion having the bit insertion hole 330, and gradually increases toward the rear. Hereinafter, a portion of the tool holder 32 connected to the rear side of the front portion and having an inner diameter larger than that of the bit insertion hole 330 is referred to as a small-diameter portion 321. A portion connected to the rear side of small-diameter portion 321 and having an inner diameter larger than that of small-diameter portion 321 is referred to as large-diameter portion 325. A portion connected to the rear side of the large diameter portion 325 and having an inner diameter larger than that of the large diameter portion 325 is referred to as a maximum diameter portion 329. Further, the maximum diameter portion 329 is a rear end portion of the tool holder 32. That is, the cylinder 33 is connected to the rear side of the maximum diameter portion 329.

Inside the tool holder 32, a first shoulder 322 is provided at a boundary portion between the small-diameter portion 321 and the large-diameter portion 325. The rear surface 323 of the first shoulder 322 is configured as a conical surface (tapered surface) having a diameter slightly increasing toward the rear. In addition, a second shoulder 326 is provided at a boundary portion between the large diameter portion 325 and the maximum diameter portion 329. The rear surface of the second shoulder 326 is configured as a plane orthogonal to the drive axis a 1.

The retainer ring 35 is a metal annular member, and is fitted into the maximum diameter portion 329 of the tool holder 32 and held slidably in the front-rear direction. The stopper ring 35 functions as a stopper portion that abuts against the large diameter portion 681 of the impact bolt 68 from behind, and restricts further rearward movement of the impact bolt 68. The retainer ring 35 also functions as a guide portion that is disposed around the small-diameter portion 684 of the impact bolt 68 and guides the sliding movement of the small-diameter portion 684. Therefore, the restriction ring 35 has an inner diameter substantially equal to the small diameter portion 684, and has an inner peripheral surface of a shape matching the rear portion of the large diameter portion 681.

Further, a cushion ring 38, which is an annular elastic body, is interposed between the stopper ring 35 and the ring holding portion 343 of the catcher 34 in the front-rear direction. The cushion ring 38 of the present embodiment is made of rubber, and is disposed between the retainer ring 35 and the ring holder 343 coaxially with the tool holder 32 in a compressed state. Accordingly, the limiter ring 35 and the ring holder 343 are biased in the direction away from each other, and are always held at the foremost position in abutment with the rear surface of the second shoulder 326 and the rearmost position in abutment with the stopper 345, respectively.

The guide sleeve 36 is a metallic cylindrical member configured to slidably hold the impact bolt 68 along the drive axis a 1. More specifically, the front half of the guide sleeve 36 is disposed around the small diameter portion 683 on the front side of the impact bolt 68, and constitutes a guide portion 360 that guides the sliding movement of the small diameter portion 683. Further, the guide portion 360 also functions as a restricting portion that abuts against the large diameter portion 681 of the impact bolt 68 from the front, thereby restricting further forward movement of the impact bolt 68. Therefore, the guide portion 360 has an inner diameter substantially equal to the small diameter portion 683, and the inner peripheral surface of the rear end portion of the guide portion 360 has a shape matching the front portion of the large diameter portion 681. Further, the rear half of the guide sleeve 36 has an inner diameter larger than the large diameter portion 681.

The guide sleeve 36 is disposed in the large diameter portion 325 of the tool holder 32, and is held slidably in the front-rear direction. The outer diameter of the guide sleeve 36 is smaller only at the front end portion than at other portions, and the other portions are uniform. Hereinafter, the distal end of the guide sleeve 36 is referred to as a small diameter portion 361, and a portion having a substantially uniform outer diameter on the rear side of the small diameter portion 361 is referred to as a large diameter portion 363. The front surface 364 of the large diameter portion 363 is configured as a conical surface (tapered surface) whose diameter slightly increases toward the rear.

The cushion ring 37 is an annular elastic body, and is disposed coaxially with the tool holder 32 in the front-rear direction between the tool holder 32 (specifically, a surface defining the front end of the small diameter portion 321) and the front end surface of the guide sleeve 36, that is, the front end surface of the small diameter portion 361. The outer diameter of the buffer ring 37 is substantially equal to the inner diameter of the small-diameter portion 321 of the tool holder 32. The inside diameter of the cushion ring 37 is larger than the outside diameter of the small diameter portion 683 of the impact bolt 68. Therefore, the cushion ring 37 is held in a state of being separated radially outward from the impact plug 68 in the small diameter portion 321.

In the present embodiment, an oil seal 39 is disposed in the tip end portion of the small diameter portion 321 of the tool holder 32, and the oil seal 39 is used to prevent lubricant from leaking out of the main shaft 31 or to prevent foreign matter from entering the main shaft 31. The front end of the cushion ring 37 abuts against a gasket disposed on the rear side of the oil seal 39. The rear end of the cushion ring 37 abuts against the guide sleeve 36. However, the front end of the cushion ring 37 may directly abut against the inner peripheral surface of the tool holder 32. A washer may be disposed on the front side of the guide sleeve 36, and the rear end of the cushion ring 37 may abut against the washer.

The cushion ring 37 of the present embodiment is made of rubber, and is disposed between the gasket and the distal end surface of the guide sleeve 36 in a slightly compressed state. Accordingly, the guide bush 36 is biased rearward with respect to the tool holder 32, and the rear end surface of the guide bush 36 is always held at a position (hereinafter referred to as an initial position) in contact with the front end surface of the restriction ring 35 disposed at the most forward position. At this time, the front surface 364 (conical surface) of the large diameter portion 363 of the guide sleeve 36 is spaced rearward from the rear surface 323 (conical surface) of the first shoulder portion 322 of the tool holder 32. That is, there is a gap between the front surface 364 of the large diameter portion 363 and the rear surface 323 of the first shoulder portion 322.

The sectional shape of the cushion ring 37 in a plane including the drive axis a1 is a substantially octagonal shape that is long in the drive axis direction (front-rear direction). That is, the dimension (maximum length) of the cushion ring 37 in the front-rear direction is larger than the dimension (maximum thickness) in the thickness direction. In addition, the sectional shape of the cushion ring 37 in a plane orthogonal to the drive axis a1 is not uniform in the front-rear direction. Therefore, as the cushion ring 37 expands and contracts (elastically deforms) in the front-rear direction, the contact area between the cushion ring 37 and the guide sleeve 36 changes. More specifically, the cushion ring 37 has a small contact area with the guide sleeve 36 at the stage of starting compression, and the contact area increases as compression progresses. The cushion ring 37 having such a shape is easily deformed at the stage of starting compression, and becomes less likely to be deformed as compression proceeds. Further, as compared with the case where the guide bush 36 has a uniform cross section in the front-rear direction, the guide bush is easily deformed in the front-rear direction, and the amount of deformation in the front-rear direction, that is, the amount of movement of the guide bush 36 can be ensured to be relatively large.

The operation of the air-hammer prevention mechanism 30 will be described below.

In a state where the tip tool 91 is pressed against the workpiece and a load is applied (hereinafter, referred to as a load state), as shown in fig. 22, the impact plug 68 is pressed by the tip tool 91 to a position where the large diameter portion 681 abuts against the stopper ring 35 from the front. The rear end of the impact pin 68 is disposed in the rear end portion of the ring holder 343. When the motor 2 is driven in this state, the hammer 67 strikes the impact bolt 68 as described above. The large diameter portion 681 of the impact plug 68 transmits the kinetic energy of the hammer 67 to the tip tool 91 without colliding with the guide sleeve 36 (guide portion 360), thereby linearly driving the tip tool 91. In this case, the cushion ring 38 can alleviate the impact when the impact bolt 68 rebounds rearward.

When the user releases the pressing of the workpiece, the tip tool 91 moves forward from the rearmost position shown in fig. 22. In this state, when the driving of the piston 65 is continued, as shown in fig. 23, the impact bolt 68 struck by the hammer 67 moves forward relative to the guide sleeve 36, and the large diameter portion 681 collides with the guide portion 360 from behind. Accordingly, the guide sleeve 36 moves forward relative to the tool holder 32 while compressing the cushion ring 37, and the front surface 364 of the large diameter portion 363 collides with the rear surface 323 of the first shoulder portion 322.

The impact bolt 68 rebounds due to the reaction force from the guide sleeve 36, and can be struck again by the hammer 67 pushed out by the reciprocation of the piston 65. However, due to the absorption of the impact by the cushion ring 37 and the movement of the guide sleeve 36 relative to the tool holder 32, the timing of the displacement of the impact pin 68 (rebound cycle) is disturbed. Therefore, a deviation occurs between the rebound period of the impact bolt 68 and the reciprocation period of the hammer 67. As a result, as shown by the broken line in fig. 23, when the small diameter portion 672 of the hammer 67 enters the catcher 34, the flange portion 673 is caught by the catch ring 341, and the reciprocation of the hammer 67 is stopped.

In the idle-run-out prevention mechanism 30 of the present embodiment, the cushion ring 37 is disposed between the tool holder 32 and the distal end surface of the guide sleeve 36 in the front-rear direction (drive axis direction). Accordingly, as compared with a configuration in which an elastic body is disposed between the tool holder 32 and the guide sleeve 36 in the radial direction, it is possible to suppress an increase in the diameter of the tool holder 32, and to realize the anti-rattling mechanism 30 that is compact in the radial direction. By using such a runaway prevention mechanism 30, the distance (so-called center height) from the drive axis a1 to the outer surface of the main body case 10 (specifically, the cylindrical portion 131), particularly, to the upper surface can be suppressed, and the usable range of the hammer drill 101 in a narrow space (for example, a corner surrounded by a wall) can be expanded. As described above, the cylindrical portion 131 is a portion that can be gripped by a user during a machining operation. Therefore, by reducing the diameter of the cylindrical portion 131, the user can easily grip the cylindrical portion 131.

The guide bush 36 is biased rearward by the cushion ring 37, and abuts against the stopper ring 35 disposed rearward of the guide bush 36. Therefore, the guide sleeve 36 can be stably held between the cushion ring 37 and the restriction ring 35, and the cushion ring 37 elastically deforms while moving forward together with the guide sleeve 36, thereby absorbing the impact.

In the anti-rattle mechanism 30, the structure of the cushion ring 37 may be appropriately changed. For example, instead of the buffer ring 37, a buffer ring 371 shown in fig. 24 or a buffer ring 372 shown in fig. 25 and 26 may be employed. The cushion ring 371 in fig. 24 is a cylindrical elastic body, and has a dimension in the axial direction larger than a dimension in the thickness direction, as in the cushion ring 37. The outer edges of the front and rear end portions of the buffer ring 371 are chamfered. Therefore, the outer edges of the front and rear end portions of the cushion ring 371 can be prevented from being damaged by being sandwiched (bitten) between the washer and the tool holder 32 and between the guide sleeve 36 and the tool holder 32. The cushion ring 372 in fig. 25 and 26 is a generally wave-shaped annular member having front and rear direction irregularities. Like the cushion ring 37, the cushion ring 372 is an elastic body having a dimension in the front-rear direction larger than that in the thickness direction and a cross-sectional shape in a plane orthogonal to the drive axis a1 that is not uniform in the front-rear direction, and is easily deformed in the front-rear direction.

Further, for example, as shown in fig. 27, a plurality of O-rings 373 may be provided side by side in the front-rear direction instead of the single cushion ring 37. Although fig. 27 shows two O-rings 373, three or more O-rings 373 may be arranged according to the space in the small-diameter portion 321. O-ring 373 is a single member and is an elastic body having a relatively small amount of deformation in the front-rear direction. In contrast, by using a plurality of O-rings 373, the amount of deformation in the front-rear direction of the entire plurality of O-rings 373 can be increased as compared with the case of using a single O-ring. Further, the plurality of O-rings 373 may all have the same structure, or may have different diameters in their respective cross sections.

The correspondence between the components of the above-described embodiment and the components of the present invention is described below. However, the components of the embodiment are merely examples, and do not limit the components of the present invention. The hammer drill 101 is an example of a "hammer drill". The main shaft 31 is an example of a "final output shaft". The drive axis a1 is an example of a "drive axis". The motor 2 and the motor shaft 25 are examples of a "motor" and a "motor shaft", respectively. The first intermediate shaft 41 is an example of a "first intermediate shaft". The impact mechanism 6 is an example of the "first driving mechanism". Second countershaft 42 is one example of a "second countershaft". The rotation transmission mechanism 7 is an example of the "second driving mechanism". The pinion gear 255 is an example of a "drive gear". The first driven gear 414 and the second driven gear 424 are examples of a "first driven gear" and a "second driven gear", respectively. The torque limiter 43 is an example of a "torque limiter". The driving-side member 74, the driven-side member 75, and the balls 76 are examples of "driving-side cam", "driven-side cam", and "balls", respectively. The biasing spring 77 is an example of a "biasing member". The main body housing 10, the bearing support body 15, the bearing 251, the bearing 412, and the bearing 422 are examples of a "housing", a "partition member", a "first bearing", a "second bearing", and a "third bearing", respectively. The first clutch mechanism 62 and the second clutch mechanism 71 are examples of a "first clutch mechanism" and a "second clutch mechanism", respectively. The mode switching dial 800 (operation portion 801) is an example of an "operation member". The first switching member 81 and the second switching member 82 are examples of a "first switching member" and a "second switching member", respectively. The first pin 803 and the second pin 805 are examples of a "first contact portion" and a "second contact portion", respectively. The support shaft 88 is an example of a "support member". The handle 17 is an example of a "handle".

The above embodiments are merely examples, and the fastening tool according to the present invention is not limited to the illustrated configuration of the hammer drill 101. For example, the following exemplary modifications may be added. In addition, only one or a plurality of these modifications can be adopted in combination with the hammer drill 101 described in the embodiment or the structural features described in each of the claims.

The hammer drill 101 may be configured to operate not by an external ac power source but by electric power supplied from a rechargeable battery. In this case, for example, a battery mounting portion to which a battery can be attached and detached is provided at the lower end portion of the handle 17 in place of the power supply line 179. The motor 2 may be a dc motor instead of an ac motor, or may be a brushless motor instead of a motor having brushes.

The structures (shape, structural members, material, etc.) of the main body case 10 and the handle 17 can be appropriately changed. For example, the main body case 10 may be formed by coupling half-divided bodies divided in the left-right direction instead of being divided in the front-rear direction. The main body case 10 may have a vibration-proof structure different from the vibration-proof structure exemplified in the above embodiments. For example, it may be: the handle 17 is elastically coupled to the main body case 10 so as to be movable relative to the main body case 10. Alternatively, it may be: the main body case 10 includes: an inner case for housing the drive mechanism 5, and an outer case including a grip portion to be gripped by a user and elastically connected to the inner case so as to be movable relative to the inner case. Unlike the above-described embodiment, the main shaft 31 and the impact mechanism 6 may be arranged so as not to be movable in the drive axis direction (front-rear direction) with respect to the main body case 10.

The vibration-proof structure of the above embodiment may be appropriately modified. For example, the number of guide shafts supporting the movable unit 180 is not limited to two, and may be one, or may be three or more. The position and support structure of the guide shaft, and the structures (shape, material, etc.) of the movable support 18 and the bearing support 15 may be appropriately changed. For example, in the above embodiment, the first guide shaft 191 is inserted through the pair of front and rear bearings 184 of the first shaft insertion portion 181, and supports the movable support 18 at two locations. Similarly, the second guide shaft 192 is inserted through a pair of front and rear bearings 184 of the second shaft insertion portion 182, and supports the movable support 18 at two locations. However, the first guide shaft 191 and the second guide shaft 192 may support the movable support 18 through one portion.

The first biasing spring 194 and the second biasing spring 195 may be replaced with other types of springs (e.g., a tension coil spring or a torsion spring) or elastic members other than springs (e.g., rubber or a synthetic resin having elasticity (e.g., a urethane foam)), and the cushioning member 197 interposed between the movable support 18 (movable unit 180) and the main body case 10 or the bearing support 15 may be formed of, for example, a synthetic resin having elasticity (e.g., a urethane foam) instead of rubber, or may be omitted. The number of the biasing members and the cushion members of the movable support 18 may be one, or three or more.

The arrangement of the first countershaft 41 (rotation axis A3) and the second countershaft 42 (rotation axis a4) with respect to the motor shaft 25 (rotation axis a2), and the arrangement of the first countershaft 41 (rotation axis A3) and the second countershaft 42 (rotation axis a4) with respect to the main shaft 31 (drive axis a1) are not limited to the arrangement exemplified in the above-described embodiment. For example, the rotation axis A3 and the rotation axis a4 may be arranged on a straight line with the rotation axis a2 interposed therebetween in a plane orthogonal to the drive axis a 1. Further, in contrast to the above-described embodiment, the first countershaft 41 and the second countershaft 42 may be disposed on the left and right sides with respect to the drive axis a1 (or the reference plane VP), respectively.

The configurations and arrangement positions of the first clutch mechanism 62, the second clutch mechanism 71, the torque limiter 73, and the mode switching mechanism 80 can be changed as appropriate.

For example, the intermediate member 63 may be omitted, and the first transmission member 64 of the first clutch mechanism 62 may be movable between a position where it engages with the motion conversion member 61 (specifically, the rotating body 611) and a position where it is spaced apart from the motion conversion member 61. That is, the first transmission member 64 may be configured to directly transmit the rotation of the first intermediate shaft 41 to the motion conversion member 61. In addition, the second clutch mechanism 71 may be configured not to transmit or cut off power between the second driven gear 424 and the second counter shaft 42, but to transmit or cut off power between the second counter shaft 42 and the drive gear 78.

The hammer drill 101 may have only the hammer drill mode and the hammer mode among the hammer drill mode, and the drill mode. In this case, only the second clutch mechanism 71 may be provided on the second intermediate shaft 42, and the first clutch mechanism 62 may be omitted. In this case, the first switching member 81 and the first spring 83 of the mode switching mechanism 80 may be omitted.

The driven-side member 75 of the torque limiter 73 and the second intermediate shaft 42 may be, for example, spline-engaged without the balls 76. Can be as follows: instead of the driven-side member 75, the driving-side member 74 is movable on the second intermediate shaft 42. The torque limiter 73 may be omitted, or may be provided in the main shaft 31.

In the mode switching mechanism 80, the shapes and the arrangements of the first switching member 81, the second switching member 82, the first spring 83, and the second spring 84, and the interlocking manner with the mode switching dial 800 can be appropriately changed. For example, the first switching member 81 for switching the first clutch mechanism 62 and the second switching member 82 for switching the second clutch mechanism 71 may be configured to move by different operation members. The operation member associated with the mode switching mechanism 80 is not limited to a rotary dial, and may be a slide-type operation lever, for example. The first and second springs 83 and 84 may be other kinds of springs (e.g., a tension coil spring or a torsion spring), and the first and second switching members 81 and 82 may not necessarily be urged. Further, on the left side where the second intermediate shaft 42 and the rotation transmission mechanism 7 are disposed with respect to the reference plane VP, there is a vacant space larger than on the right side where the first intermediate shaft 41 and the impact mechanism 6 are disposed. Therefore, the mode switching mechanism 80 may be provided on the left side portion of the main body case 10 by using the space.

The anti-runaway mechanism 30 may be omitted, or other types of anti-runaway mechanisms may be provided.

In view of the gist of the present invention and the above-described embodiments, the following embodiments are constructed. The following embodiments can be used in combination with the hammer drill 101 and the modification described above or the structural features described in each of the embodiments.

[ means 1]

The first drive mechanism includes a swinging member, a piston, and an impact member, wherein,

the swing member is disposed on the first intermediate shaft and configured to swing in accordance with rotation of the first intermediate shaft;

the piston is configured to reciprocate along the drive axis in accordance with the oscillation of the oscillating member;

the striker is configured to linearly move by an air spring generated by the reciprocating motion of the piston, and to linearly drive the tip tool.

The motion conversion member 61 (the swinging member 616), the piston 65, and the hammer 67 are examples of a "swinging member", "piston", and "hammer" in the present embodiment, respectively.

[ means 2]

The second drive mechanism is constituted as a reduction gear mechanism including a first rotation transmission gear and a second rotation transmission gear, wherein,

the first rotation transmission gear is disposed on the second intermediate shaft and configured to rotate together with the second intermediate shaft;

the second rotation transmission gear is provided on an outer periphery of the final output shaft and is engaged with the first rotation transmission gear.

The drive gear 78 and the driven gear 79 are examples of a "first rotation transmission gear" and a "second rotation transmission gear" in the present embodiment, respectively.

[ means 3]

The support member is fixed to the partitioning member.