阅读说明：本技术 电动工具 (Electric tool ) 是由 内田洋树 曹健 于 2018-08-10 设计创作，主要内容包括：本发明提供一种电动工具,通过在内罩与齿圈的支撑结构下功夫而实现外壳的小型化。电动工具具有使电机的旋转减速的减速机构、收纳电机和减速机构的外壳,作为减速机构使用具有位于行星齿轮的外侧的齿圈(35)的行星齿轮减速机构,在电机与减速机构之间通过外壳保持支撑减速机构轴承的内罩(20)。内罩(20)具有向轴向突出的凹部、即切口部(38),齿圈具备与凹部对应的凸部、即突出部(25),通过使这些卡合而以齿圈(35)相对于外壳不会在圆周方向上旋转的方式进行保持。(The invention provides an electric tool, which realizes the miniaturization of a shell by devising a supporting structure of an inner cover and a gear ring. The electric tool has a speed reduction mechanism for reducing the rotation speed of the motor, and a housing for housing the motor and the speed reduction mechanism, wherein a planetary gear speed reduction mechanism having a ring gear (35) positioned outside the planetary gear is used as the speed reduction mechanism, and an inner cover (20) for supporting a speed reduction mechanism bearing is held by the housing between the motor and the speed reduction mechanism. The inner cover (20) has a notch (38) which is a recess projecting in the axial direction, and the ring gear has a projection (25) which is a projection corresponding to the recess, and these are engaged with each other to hold the ring gear (35) so as not to rotate in the circumferential direction with respect to the housing.)

1. An electric tool having a motor, a speed reduction mechanism for reducing a rotation speed of the motor, and a housing for housing the motor and the speed reduction mechanism,

the speed reduction mechanism includes a planetary gear, a ring gear located outside the planetary gear, and a sun gear located inside the planetary gear and connected to the motor,

the electric power tool is characterized in that,

an inner cover is disposed between the motor and the speed reducing mechanism and held by the housing, the inner cover supporting a bearing of the speed reducing mechanism,

the outer peripheral surface of the inner cover is supported by the inner peripheral surface of the ring gear.

2. An electric tool having a motor, a speed reduction mechanism for reducing a rotation speed of the motor, and a housing for housing the motor and the speed reduction mechanism,

the speed reduction motor has a planetary gear, a ring gear located outside the planetary gear, and a sun gear located inside the planetary gear and connected to the motor,

the electric power tool is characterized in that,

an inner cover which supports a bearing of the speed reducing mechanism and is held by the housing,

the inner cover is partially housed in an inner peripheral side of the ring gear.

3. The power tool of claim 2,

the inner cover is disposed between the motor and the reduction mechanism, and has an outer peripheral surface supported by an inner peripheral surface of the ring gear.

4. The electric power tool according to any one of claims 1 to 3,

the ring gear is made of metal or synthetic resin, a gear portion is formed on the inner side, and a cylinder portion extending in the axial direction in a manner of being adjacent to the gear portion is formed,

a part of the inner cover is accommodated inside the cylindrical portion.

5. The power tool of claim 4,

the inner cover has a concave-convex portion protruding or recessed in a radial direction, the ring gear has a concave-convex portion having a concave-convex shape corresponding to the concave-convex portion, and relative rotation between the ring gear and the inner cover is prevented by engagement of the concave-convex portion with the concave-convex portion.

6. The power tool of claim 5,

the number of the concave-convex portions and the number of the concave-convex portions are plural.

7. The power tool of claim 6,

the rotating shaft of the motor and the rotating center of the speed reducing mechanism are arranged coaxially,

the inner cover fixes one of motor bearings supporting the rotating shaft and one of gear bearings supporting the reduction mechanism, and has a first cylindrical portion holding an outer peripheral surface of the motor bearing and a second cylindrical portion holding an outer peripheral surface of the gear bearing.

8. The power tool of claim 7,

the housing is composed of a synthetic resin member dividable by a dividing surface including a rotational axis of the motor, the inner cover is held by the housing so as to intersect the dividing surface,

the inner cover and the outer cover are formed with a rotation stopper so as not to rotate relative to each other.

9. The power tool of claim 7,

based on the power transmission mechanism that converts the output of the speed reduction mechanism into the driving force of the tip end tool,

the housing is formed by a cup-shaped metal case for accommodating the power transmission mechanism,

the ring gear has the same diameter as the opening edge of the metal case and is arranged so as to be aligned in the axial direction with the opening edge.

Technical Field

The present invention relates to an electric power tool in which a reduction in size of the apparatus itself is achieved by improving a mounting structure of a planetary gear reduction mechanism and a bearing holding portion of a motor.

Background

Electric tools are known in which a power transmission mechanism is driven to rotate a tip tool by decelerating a rotational force of a motor, and impact driving, impact wrenches, and hydraulic driving are widely used as examples thereof. For example, in an impact tool, a rotational force is transmitted to a hammer, an anvil is struck by the hammer, the rotational force of a motor is converted into an intermittent striking force in a rotational direction, and a bolt or the like is fastened by a tip tool using the striking force. When a wrench of a switch of the impact tool is pulled, the motor is driven, and the main shaft is rotated by the reduction mechanism. The speed reduction mechanism is a mechanical device that reduces an input rotation speed generated by a motor using a plurality of gears and outputs the reduced rotation speed at a low rotation speed. A torque proportional to the reduction ratio can be obtained by the reduction mechanism. When the main shaft rotates, the hammer coupled to the main shaft by a cam mechanism using the hammer case and the cam roller rotates. When the hammer rotates, the anvil rotates by transmitting a rotational force between the striking claw of the hammer and the blade portion (struck claw) of the anvil. For example, an attachment portion of a tip tool is formed at the axial tip of the anvil, and a screw or a bolt is fastened by the tip tool such as a hexagonal wrench attached thereto.

In the case of performing a screw fastening operation on wood, the hammer and the anvil rotate together (continuously rotate) for a certain period of time from the start of fastening. Then, as the tightening progresses, the reaction torque generated in the screw gradually increases, and if the reaction torque exceeds the spring pressure of the hammer spring, the hammer gradually retreats toward the motor side while gradually compressing the hammer spring along the shapes of the anvil cam groove and the hammer cam groove. By this backward movement of the hammer, the contact length (engagement amount) in the front-rear direction between the striking claw of the hammer and the struck claw of the anvil becomes small. When the engagement amount between the striking claw of the hammer and the struck claw of the anvil is 0, the engagement of the hammer with the anvil in the rotational direction is released. When the striking claw of the hammer retreats and passes over the striking claw of the anvil, the hammer is pushed out toward the tool side by the compression force of the hammer spring and collides with the next striking claw of the anvil, thereby applying a strong striking force to the anvil. In this way, the striking claw provided on the hammer and the struck claw provided on the anvil repeat the operation of disengaging, advancing, and striking (striking operation) until the fastening of the screw is completed.

Disclosure of Invention

The present invention has been made in view of the above-described background, and an object thereof is to provide an electric power tool that is reduced in size while suppressing an increase in size of a housing by devising a support structure for an inner cover and a ring gear.

Another object of the present invention is to provide an electric power tool in which an outer edge portion of an inner cover is supported on an inner peripheral surface of a ring gear of a planetary gear reduction mechanism, and a housing is directly positioned on an outer peripheral surface side of the inner cover.

Another object of the present invention is to provide an electric power tool in which the rotation center of the spindle and the rotation center of the ring gear can be aligned with each other with high accuracy by the inner cover.

The invention disclosed in this application follows if features of representative structures are described.

According to one aspect of the present invention, an electric power tool includes a motor, a speed reduction mechanism for reducing rotation of the motor, and a housing for housing the motor and the speed reduction mechanism, wherein the speed reduction mechanism includes a planetary gear, a ring gear located outside the planetary gear, and a sun gear located inside the ring gear and connected to the motor, and is disposed between the motor and the speed reduction mechanism so as to hold a bearing for supporting the speed reduction mechanism by the housing, and an outer peripheral surface of an inner cover is supported by an inner peripheral surface of the ring gear. In other words, a part of the inner cover is housed on the inner peripheral side of the ring gear. The inner cover is an integrally formed product, and the outer peripheral surface is supported by the inner peripheral surface of the ring gear.

According to another feature of the present invention, the ring gear is made of metal or synthetic resin, the gear portion is formed on an inner side, a cylindrical portion extending in an axial direction is formed so as to be adjacent to the gear portion, and a part of the inner cover is housed inside the cylindrical portion. The inner cover has a concave-convex portion protruding or recessed in the radial direction, the ring gear has a concave-convex portion having a concave-convex shape corresponding to the concave-convex portion, and the relative rotation between the ring gear and the inner cover is prevented by the engagement of the concave-convex portion and the concave-convex portion. A plurality of the concave-convex parts and the convex-concave parts are respectively arranged.

According to another feature of the present invention, the rotation shaft of the motor is arranged coaxially with the rotation center of the reduction mechanism. The inner cover fixes one of motor bearings for supporting a rotating shaft and one of gear bearings for supporting the rotating shaft and the reduction gear, and has a first cylindrical portion for holding an outer peripheral surface of the motor bearing and a second cylindrical portion for holding an outer peripheral surface of the gear bearing. The housing includes a synthetic resin member divided by a dividing plane including a rotational axis of the motor, the inner cover is held by the housing so as to intersect the dividing plane, and the inner cover and the housing form a rotation stop portion so as not to rotate relative to each other. The housing is formed by a cup-shaped metal case that houses a power transmission mechanism that converts the output of the reduction gear into the driving force of the tip tool, and the ring gear is arranged in the same diameter as the opening edge of the metal case and in axial alignment with the opening edge.

Effects of the invention

According to the present invention, since the inner cover is not positioned radially outward of the outer peripheral surface of the ring gear, the radial dimension of the housing of the electric power tool can be made to be the minimum dimension necessary for housing the ring gear, and the electric power tool can be downsized. Further, since the outer peripheral surface of the inner cover is held on the inner peripheral surface of the ring gear, the rotation axis of the spindle and the center axis of the ring gear can be maintained coaxially, and the rotational accuracy can be ensured. Further, since the concave-convex portion formed on the spindle side and the concave-convex portion formed on the inner cover side are engaged with each other, the inner cover held by the housing so as not to rotate in the rotational direction can be used to prevent the ring gear from rotating on its own axis.

Drawings

Fig. 1 is a side view of an impact tool 1 of an embodiment of the present invention.

Fig. 2 is a longitudinal sectional view showing the internal structure of the impact tool 1 of the embodiment of the present invention.

Fig. 3 is an enlarged view of a portion B in fig. 2.

Fig. 4 is a perspective view of the inner cover 20 and the ring gear 35 in fig. 2.

Fig. 5 is a view in a state where the inner cover 20 and the ring gear 35 in fig. 2 are assembled, (a) is a front view, (B) is a view from the E direction of (a), and (C) is a view from the F direction of (a).

FIG. 6(A) is a sectional view taken along line C-C in FIG. 5(A), and (B) is a sectional view taken along line D-D in FIG. 5 (A).

Fig. 7 is a perspective view of the inner cover 20A and the ring gear 35A of the impact tool of the second embodiment of the present invention.

Fig. 8 is a view in a state where the inner cover 20A in fig. 7 is assembled with the ring gear 35A, (a) is a front view, (B) is a sectional view of C-C in (a), and (C) is a sectional view of D-D in (a).

Fig. 9 is a perspective view of the inner cover 20B and the ring gear 35B of the impact tool of the third embodiment of the present invention.

Fig. 10 is a view of a state where the inner cover 20B and the ring gear 35B in fig. 9 are assembled, (a) is a front view, (B) is a sectional view of C-C in (a), and (C) is a sectional view of D-D in (a).

Fig. 11 is an enlarged view of the vicinity of the inner cover 20C and the ring gear 35C of the impact tool of the fourth embodiment of the invention.

Fig. 12 is a perspective view of the inner cover 20C and the ring gear 35C in fig. 11.

Fig. 13 is a view of a state where the inner cover 20C in fig. 11 is assembled with the ring gear 35C, (a) is a front view, (B) is a C-C sectional view in (a), and (C) is a D-D sectional view in (a).

Fig. 14 is a perspective view of an inner cover 20D and a ring gear 35D of an impact tool according to a fifth embodiment of the present invention.

Fig. 15 is a view of a state where the inner cover 20D in fig. 14 is assembled with the ring gear 35D, (a) is a front view, (B) is a sectional view of C-C in (a), and (C) is a sectional view of D-D in (a).

In the figure: 1-impact tool, 2-main body case, 2 a-machine body portion, 2 b-handle portion, 2 c-battery mounting portion, 3-hammer case, 4-motor, 4 b-stator core, 4 c-rotation shaft, 5a, 5 b-insulator, 6-trigger switch, 6 a-trigger lever, 6D-plunger, 7-forward/reverse rotation switching lever, 8a, 8 b-bearing, 9 a-bearing, 9 b-bearing, 11-sensor substrate, 13-cooling fan, 14-control circuit substrate, 15-rib, 16 a-power line, 16 b-signal line, 17 a-air suction port, 17 b-air discharge port, 18 a-18 h-bolt, 19 a-19 h-bolt boss, 20A-20D-inner cover, 21-first cylindrical portion, 21 a-opening portion, 21 b-bearing holding surface, 22-coupling portion, 23-second cylindrical portion, 23 b-bearing holding surface, 24-extension portion, 24 a-outer peripheral surface 24 b-protrusion portion, 25a, 25 b-recess portion, 26-cutout portion, 28-switch button, 29-light emitting mechanism, 30-speed reducing mechanism, 31-sun gear, 32-planetary gear, 35-ring gear, 36-gear portion, 37-cylindrical inner surface, 38 c-cutout portion, 39a, 39b, 39 d-protrusion portion, 40-striking mechanism, 41-main shaft, 42-hammer, 42a, 42 b-striking pawl, 43-hammer spring, 44-stopper ring, 46-fitting hole, 47-planetary gear frame portion, 50-anvil, 51a, 51 b-blade portion, 52-mounting hole, 60-tip tool holding portion, 61-sleeve, 62-steel ball, 63-compression spring, 65-restriction step portion, 100-battery, 101-release switch, a 1-axis (of rotating shaft).

Detailed Description