阅读说明：本技术 动力工具 (Power tool ) 是由 仲野领祐 横山仁一 于 2019-04-12 设计创作，主要内容包括：本发明提供一种防尘性高的动力工具。该动力工具具有：外壳(2)；马达(3),其支撑于外壳(2)内；推杆(7),其支撑于外壳(2)内且受到马达(3)的驱动力而驱动；环状部件(923)及O型圈(924),其包围推杆(7)的外周面且将推杆(7)的外周面密封；以及保持部,其支撑于外壳(2),将环状部件(923)及O型圈(924)包围并以使环状部件(923)及O型圈(924)与推杆(7)的外周面接触的方式支撑,并且容纳润滑油,随着推杆(7)的驱动,O型圈(924)按压保持部的至少一部分,从而向O型圈(924)与推杆(7)的外周面之间供给润滑油。(The invention provides a power tool with high dust resistance. The power tool has: a housing (2); a motor (3) supported within the housing (2); a push rod (7) which is supported in the housing (2) and is driven by the driving force of the motor (3); an annular member (923) and an O-ring (924) that surround the outer peripheral surface of the plunger (7) and seal the outer peripheral surface of the plunger (7); and a holding portion that is supported by the housing (2), surrounds the annular member (923) and the O-ring (924), supports the annular member (923) and the O-ring (924) so as to be in contact with the outer peripheral surface of the push rod (7), contains lubricating oil, and, when the push rod (7) is driven, the O-ring (924) presses at least a part of the holding portion, thereby supplying the lubricating oil between the O-ring (924) and the outer peripheral surface of the push rod (7).)

1. A power tool, comprising:

a housing;

a drive source that rotationally drives the housing;

a driving body supported in the housing and operated by a driving force of the driving source; and

and a holding unit which is disposed around the driving body, contains a fluid including at least air or a lubricant, and discharges the fluid to the outside by an external force caused by the driving of the driving source.

2. The power tool of claim 1,

a sealing part for sealing the peripheral surface of the driving body,

the holding portion supports the seal portion and supplies the lubricant to the seal portion by the external force.

3. The power tool of claim 2,

the external force is transmitted to the holding portion via the sealing portion.

4. The power tool according to claim 2 or 3,

the driving body can move relative to the shell,

the retaining portion is positioned relative to at least a portion of the housing,

the sealing portion moves in accordance with the movement of the driving body, and the sealing portion biases at least a part of the holding portion, so that the external force is transmitted to the holding portion, and the lubricant is supplied to the outer peripheral surface of the driving portion.

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

the holding part is an elastic body and is provided with a lubricant accommodating part filled with the lubricant and an accommodating part which is recessed towards a preset direction and accommodates at least one part of the sealing part,

at least a part of the holding portion is pressed by the sealing portion and elastically deformed, so that the lubricant containing portion and the containing portion communicate with each other.

6. The power tool of claim 4,

the holding portion has a curved surface facing the outer peripheral surface of the driving portion and protruding toward the outer peripheral surface.

7. The power tool according to any one of claims 1 to 5,

the sealing part is provided with an O-shaped ring.

8. The power tool according to any one of claims 1 to 7,

the housing is provided with an opening part for inserting a part of the driving body and communicating with the outside,

the holding portion discharges the fluid toward the opening portion by the external force.

9. The power tool according to any one of claims 1 to 8,

the holding portion is provided with a check valve that allows the fluid to flow from the inside of the housing to the outside of the housing and suppresses the fluid from flowing from the outside of the housing to the inside of the housing.

10. The power tool of claim 9,

the driving body is a driving shaft extending in a predetermined direction,

the one-way valve portion has an extending portion that extends toward the axis of the drive shaft and is inclined with respect to a direction orthogonal to the axial direction of the drive portion.

11. The power tool according to any one of claims 1 to 10,

the holding part has an elastic member for defining a space for enclosing the fluid,

the elastic member deforms in response to the external force to reduce the volume of the space, and the holding portion discharges the fluid in the space to the outside.

12. The power tool of claim 11,

the elastic member is formed with a through hole through which the drive shaft is inserted,

the elastic member deforms in response to driving of the drive shaft to reduce a volume of the space, and the fluid is discharged to the outside of the housing through the through hole.

13. The power tool according to claim 11 or 12,

a support part for supporting at least a part of the elastic part,

an air suction portion for allowing the fluid to flow into the space is provided between the support portion and at least a part of the elastic member.

14. The power tool of claim 12,

the above-mentioned drive shaft extends in a predetermined direction,

a groove communicating with the through hole is formed in the elastic member,

the lubricant is filled in the groove.

15. The power tool according to any one of claims 1 to 14,

the driving body is configured to be capable of reciprocating relative to the housing,

further comprising:

a gear portion that is interposed between the drive source and the drive body on a transmission path of the drive force of the drive source, and that rotates by receiving the drive force of the drive source; and

and a motion conversion mechanism which is interposed between the gear portion and the drive body on a transmission path of the driving force of the driving source, and converts the rotational motion of the gear portion into the reciprocating motion of the drive body.

Technical Field

The present invention relates to a power tool.

Background

Conventionally, as a power tool for cutting wood, steel, metal pipes, and the like (materials to be cut), a reciprocating tool in which a saw blade is used as a tip tool has been widely used. As such a reciprocating tool using a saw blade as a tip tool, there is known a knife saw including: a motor; a motion conversion unit that converts a rotational force of the motor into a reciprocating movement; and a push rod supported by the housing so as to be capable of reciprocating, one end portion of the push rod protruding from an opening formed in the housing, and a saw blade attachable to the front end of the push rod (see patent document 1).

In the conventional knife saw, a sealing portion having a dust-proof function is generally provided around an opening portion of a housing so that dust (cutting dust) generated during a cutting operation does not enter the housing.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2008-114343

Disclosure of Invention

Problems to be solved by the invention

However, the conventional sealing portion of the knife saw cannot sufficiently prevent dust generated during operation from entering the housing, and there is a problem that operation failure due to the dust occurs and durability is reduced.

Accordingly, an object of the present invention is to provide a power tool having high dust-proof performance.

Means for solving the problems

In order to solve the above problem, the present invention provides a power tool including: a housing; a drive source that rotationally drives the housing; a driving body supported in the housing and operated by a driving force of the driving source; and a holding unit which is disposed around the driving body, contains a fluid including at least air or a lubricant, and discharges the fluid to the outside by an external force caused by the driving of the driving source.

According to the above configuration, the dust-proof performance can be improved by the discharged fluid.

Preferably, the drive device further includes a sealing portion that seals an outer peripheral surface of the drive body, and the holding portion supports the sealing portion and supplies the lubricant to the sealing portion by the external force.

According to the above configuration, since the lubricant is supplied to the seal portion in accordance with the driving of the driving portion, the deterioration (wear) of the seal portion can be suppressed. This can suitably suppress the intrusion of dust generated during operation into the housing.

Further, it is preferable that the external force is transmitted to the holding portion via the sealing portion.

According to such a configuration, the lubricant can be supplied to the seal portion appropriately in accordance with the driving of the driving portion by shortening the distance from the holding portion to the seal portion.

Preferably, the driving portion is movable relative to the housing, the holding portion is positioned relative to at least a portion of the housing, and the sealing portion moves integrally with the driving portion to apply a force to at least a portion of the holding portion, thereby supplying the lubricant between the sealing portion and the driving portion.

With this configuration, since the lubricant is supplied to the periphery of the seal portion in accordance with the driving of the driving portion at the timing when the shortage of the lubricant to the seal portion occurs, an appropriate amount of the lubricant can be supplied to the seal portion at an appropriate timing, and further deterioration (wear) of the seal portion can be suppressed. This can suitably suppress the intrusion of dust generated during operation into the housing.

Preferably, the holding portion is an elastic body, and includes a lubricant accommodating portion filled with the lubricant and an accommodating portion recessed in a predetermined direction and accommodating at least a part of the sealing portion, and the lubricant accommodating portion and the accommodating portion communicate with each other by at least a part of the holding portion being elastically deformed by being pressed by the sealing portion.

This enables the lubricant to be supplied to the seal portion with a simple configuration.

Preferably, the holding portion has a curved surface projecting toward the driving portion.

With this configuration, the holding portion can be appropriately deformed by the pressing force from the sealing portion.

Preferably, the sealing portion has an O-ring.

According to such a configuration, when the O-ring moves integrally with the driving portion due to deterioration of the O-ring or the like, the O-ring presses a part of the holding portion in accordance with driving of the driving portion, and the lubricant is supplied between the sealing portion and the driving portion, so that further deterioration (abrasion) of the O-ring can be suppressed. This can suitably suppress the intrusion of dust generated during operation into the housing.

Preferably, the housing is provided with an opening through which a part of the driving body is inserted and communicates with the outside, and the holding portion is configured to discharge the fluid toward the opening by the external force.

With this configuration, dust can be prevented from entering the interior through the opening communicating with the outside.

Preferably, the holding portion is provided with a one-way valve portion that allows the fluid to flow from the inside of the housing to the outside of the housing and suppresses the fluid from flowing from the outside of the housing to the inside of the housing.

With this configuration, intrusion of dust and the like from the outside of the housing into the inside can be appropriately suppressed.

Preferably, the drive body is a drive shaft extending in a predetermined direction, and the one-way valve portion includes an extending portion extending toward an axis of the drive shaft and inclined with respect to a direction orthogonal to an axial direction of the drive portion.

According to such a configuration, intrusion of dust and the like that move in the direction in which the drive shaft extends and approach can be appropriately suppressed.

Preferably, the holding portion includes an elastic member that defines a space for enclosing the fluid, and the elastic member deforms in response to the external force to reduce a volume of the space, so that the holding portion discharges the fluid in the space to the outside.

With this configuration, the fluid can be appropriately discharged.

Preferably, the elastic member is formed with a through hole through which the drive shaft is inserted, and the elastic member is deformed by driving of the drive shaft to reduce a volume of the space, so that the fluid is discharged to the outside of the housing through the through hole.

With this configuration, the dust around the drive shaft can be discharged to the outside.

Preferably, the fluid supply device further includes a support portion that supports at least a part of the elastic member, and an air suction portion that allows the fluid to flow into the space is provided between the support portion and at least a part of the elastic member.

With this configuration, the fluid can be repeatedly discharged.

Further, in the power tool according to claim 12, the drive shaft extends in a predetermined direction, a groove communicating with the through hole is formed in the elastic member, and the groove is filled with the lubricant.

According to this configuration, since the groove is filled with the lubricant, the lubricant can be discharged for a long time, and the dust can be appropriately prevented from entering the casing.

Preferably, the drive portion is configured to be capable of reciprocating with respect to the housing, and further includes a gear portion that is interposed between the drive source and the drive portion on a transmission path of the drive force of the drive source and rotates by the drive force of the drive source, and a motion conversion mechanism portion that is interposed between the gear portion and the drive portion on the transmission path of the drive force of the drive source and converts the rotational motion of the gear portion into the reciprocating motion of the drive portion, and the seal portion moves integrally with the drive portion to press at least a part of the holding portion, thereby supplying the lubricant to the seal portion.

According to such a configuration, when the sealing portion and the driving portion reciprocate integrally due to deterioration of the sealing portion or the like, the sealing portion presses a part of the holding portion in accordance with the reciprocation of the driving portion, and thereby the lubricant is supplied between the sealing portion and the driving portion, and therefore further deterioration (abrasion) of the sealing portion can be suppressed. This can suitably suppress the intrusion of dust generated during operation into the housing.

Effects of the invention

According to the power tool of the present invention, intrusion of dust generated during operation into the power tool main body can be suitably suppressed.

Drawings

Fig. 1 is a cross-sectional side view showing an internal structure of a blade saw according to a first embodiment of the present invention.

Fig. 2 is an exploded perspective view showing the push rod, the dust-proof mechanism, the main body case, and the push rod cover of the knife saw according to the first embodiment of the present invention.

Fig. 3 is a cross-sectional detailed view showing a front portion, a blade mounting portion, a dust-proof mechanism portion, and a periphery of a push rod of the knife saw according to the first embodiment of the present invention.

Fig. 4 is a diagram showing an elastic body of a first dust-proof mechanism of a knife saw according to a first embodiment of the present invention, wherein (a) is a rear view, (b) is a right side view, and (c) is a front view.

Fig. 5 is a sectional side view of an elastic body of a first dust prevention mechanism of a knife saw according to a first embodiment of the present invention, where (a) is a sectional view taken along line VA-VA in fig. 4(a), and (B) is a sectional view taken along line VB-VB in fig. 4 (a).

Fig. 6 is a cross-sectional detailed view showing a front portion, a blade mounting portion, a dust-proof mechanism portion, and a periphery of a push rod of the knife saw according to the first embodiment of the present invention.

Fig. 7 is a cross-sectional side view showing an internal structure during operation of the knife saw according to the first embodiment of the present invention, and shows a state in which the switching portion is in the pressing posture and the blade attachment portion is positioned at the front position.

Fig. 8 is a cross-sectional side view showing an internal structure during operation of the knife saw according to the first embodiment of the present invention, and shows a state in which the switching portion is in the pressing posture and the blade attachment portion is located at the rear position.

Fig. 9 is a cross-sectional side view showing an internal structure during operation of the knife saw according to the first embodiment of the present invention, and shows a state in which the switching portion is in the release posture and the blade attachment portion is positioned at the front position.

Fig. 10 is a cross-sectional side view showing an internal structure during operation of the knife saw according to the first embodiment of the present invention, and shows a state in which the switching portion is in the release posture and the blade attachment portion is located at the rear position.

Fig. 11 is a view schematically showing the behavior of the tip end portion of the push rod of the knife saw with respect to the main body case of the gear housing in the work in which the switching portion is in the release posture.

Fig. 12 is a cross-sectional detailed view showing the front portion of the push rod, the blade mounting portion, the dust-proof mechanism portion, and the periphery thereof corresponding to point (i) of fig. 11.

Fig. 13 is a cross-sectional detailed view corresponding to point (ii) of fig. 11 showing the front portion of the push rod, the blade mounting portion, the dust-proof mechanism portion, and the periphery thereof.

Fig. 14 is a cross-sectional detailed view corresponding to point (iii) of fig. 11 showing the front portion of the push rod, the blade mounting portion, the dust-proof mechanism portion, and the periphery thereof.

Fig. 15 is a cross-sectional detailed view showing the front portion of the push rod, the blade mounting portion, the dust-proof mechanism portion, and the periphery thereof corresponding to point (iv) of fig. 11.

Fig. 16 is a diagram illustrating an effect of the second dust-proof mechanism of the dust-proof mechanism portion of the blade saw according to the first embodiment of the present invention, and shows a state where the blade mounting portion is located at a front position.

Fig. 17 is a diagram illustrating an effect of the second dust-proof mechanism of the dust-proof mechanism portion of the blade saw according to the first embodiment of the present invention, and shows a state in which the blade mounting portion is moved rearward from the front position.

Fig. 18 is a diagram illustrating an effect of the second dust-proof mechanism of the dust-proof mechanism portion of the knife saw according to the first embodiment of the present invention, and shows a state where the blade mounting portion is located at a rear position.

Fig. 19 is an enlarged view of the XVIII portion of fig. 18.

Fig. 20 is a diagram illustrating an effect of the second dust-proof mechanism of the dust-proof mechanism portion of the blade saw according to the first embodiment of the present invention, and shows a state where the blade mounting portion is returned from the rear position to the front position.

Fig. 21 is a cross-sectional detailed view showing a front portion, a blade mounting portion, a dust-proof mechanism portion, and a periphery of a push rod of a knife saw according to a second embodiment of the present invention.

Fig. 22 is an enlarged view of the XXII portion of fig. 21.

Fig. 23 is a diagram illustrating an effect of the knife saw according to the second embodiment of the present invention, and is a cross-sectional detail view showing the dust-proof mechanism and its periphery.

Detailed Description

Hereinafter, a blade saw 1 as an example of the power tool according to the first embodiment of the present invention will be described. In the following description, "up" shown in fig. 1 is defined as an upward direction, "down" is defined as a downward direction, "front" is defined as a forward direction, and "rear" is defined as a rearward direction. In addition, "right" when the blade saw 1 is viewed from the rear is defined as a right direction, and "left" is defined as a left direction. In the present specification, when a dimension, a numerical value, or the like is referred to, not only a dimension and a numerical value that are completely consistent with the dimension, the numerical value, or the like, but also a dimension, a numerical value, or the like that are substantially consistent (for example, in a case where the dimension, the numerical value, or the like is within a manufacturing error) are included. The terms "same," "orthogonal," "parallel," "coincident," "flush," "constant," "symmetrical," and the like, also include "substantially identical," "substantially orthogonal," "substantially parallel," "substantially coincident," "substantially flush," "substantially constant," "substantially symmetrical," and the like.

The blade saw 1 is an electric reciprocating tool for cutting wood, steel, pipes, and the like (materials to be cut). As shown in fig. 1, the blade saw 1 includes: the case 2 to which the battery pack P is detachably attached, the motor 3, the control board 4, the controller portion 5, the gear portion 6, the push rod 7, the blade attachment portion 8 to which the blade Q (see fig. 2) can be attached, and the dust-proof mechanism portion 9.

The housing 2 forms an outer contour of the blade saw 1, and has a motor housing 21, a handle housing 22, a gear housing 23, and a front cover 24.

The motor housing 21 and the handle housing 22 are configured as divided housings divided by a dividing plane (virtual plane) passing through the center portion of the housing 2 and orthogonal to the left-right direction, and the respective divided right and left portions are configured to be symmetrical with respect to the dividing plane.

As shown in fig. 1, the motor housing 21 has a cylindrical portion 211 and an extension portion 212. The cylindrical portion 211 is formed in a substantially cylindrical shape extending in the front-rear direction, and accommodates the motor 3 and the control board 4. The protruding portion 212 is formed in a substantially cylindrical shape extending rearward and downward from the lower end of the rear portion of the cylindrical portion 211.

As shown in fig. 1, the handle case 22 is formed in a substantially コ -shaped side view and positioned behind the motor case 21. The handle housing 22 has a grip portion 221, a first connection portion 222, and a second connection portion 223.

The grip portion 221 is a portion gripped by an operator during a work, and extends in the vertical direction. A manually operable trigger 22A for controlling the start and stop of the motor 3 is provided at an upper front portion of the grip portion.

The first connecting portion 222 extends forward from the upper end portion of the grip portion 221. The front end of the first connection portion 222 is connected to the upper end of the rear portion of the cylindrical portion 211 of the motor housing 21.

The second connection portion 223 forms a lower portion of the handle housing 22 and extends in the front-rear direction. The front end of the second connecting portion 223 is connected to the rear end of the protruding portion 212 of the motor housing 21.

Further, a battery connection portion 223A to which the battery pack P can be connected is provided at a lower end portion of the second connection portion 223. Battery connection portion 223A is provided with a battery connection terminal portion 223B to be connected to a terminal portion, not shown, of battery pack P.

As shown in fig. 1, the gear housing 23 extends forward from the cylindrical portion 211 of the motor housing 21. The gear housing 23 accommodates the gear portion 6 and the push rod 7. A base 23D that abuts against the material to be cut during the cutting operation is provided at the distal end portion of the gear housing 23. The gear housing 23 mainly includes a main body case 230, a plunger cover 231, a pair of slide metals 232A and 232B, a bearing 233, a cover 234, and a switching portion 235.

As shown in fig. 2, the main body case 230 is formed in a substantially cylindrical shape extending in the front-rear direction. The main body case 230 supports the structural elements inside the gear housing 23. The main body case 230 is a divided housing divided by a dividing surface (virtual surface) that passes through the center of the main body case 230 in the vertical direction and is orthogonal to the vertical direction. As shown in fig. 3, the main body case 230 has an opening 23A, a first protruding portion 23B, and a second protruding portion 23C.

The opening 23A has a wall protruding inward of the main body case 230 from the inner peripheral surface of the main body case 230. The wall is provided over the entire circumferential surface of the inner circumferential surface of the main body case 230, and an opening 23a is formed by a protruding end surface thereof. Through the opening 23a, the housing 2 (gear housing 23) communicates with the outside. The push rod 7 is inserted into the opening 23A (opening 23A). The opening 23A is an example of the "opening" of the present invention.

The first protruding portion 23B is located rearward of the opening 23a, and protrudes inward of the main body case 230 from the inner peripheral surface of the upper portion of the main body case 230.

The second protruding portion 23C is located rearward of the first protruding portion 23B, and protrudes inward of the main body case 230 from the inner peripheral surface of the lower portion of the main body case 230.

The plunger cover 231 shown in fig. 1 and 2 is a metal member that protrudes in the front-rear direction. A sliding metal arrangement portion 231a provided with a sliding metal 232A is formed at the front portion of the plunger cover 231, and a sliding metal arrangement portion 231B provided with a sliding metal 232B is formed at the rear portion. The sliding metal arrangement parts 231a and 231b extend in the front-rear direction and are recessed upward in a rectangular shape. The pusher cover 231 includes a swing shaft 231A and a dust-proof mechanism housing 231B (see fig. 3).

The swing shaft 231A is provided at a lower portion of a front portion of the pushrod housing 231 and extends in the left-right direction. The swing shaft 231A has left and right ends supported by the main body case 230. The lever cover 231 is configured to be swingable in the vertical direction with respect to the main body case 230 about the axis of the swing shaft 231A.

As shown in fig. 3, the dust-proof mechanism accommodating portion 231B is formed at the front portion of the pushrod cover 231 and extends in the front-rear direction. The dust-proof mechanism accommodating portion 231B has a cylindrical portion 231C and a bottom portion 231D.

The tube 231C is formed in a hollow tube shape extending in the front-rear direction. The bottom 231D is connected to the rear end of the tube 231C and extends inward of the tube 231C. A through hole is formed in a substantially central portion of the bottom 231D, and the push rod 7 is inserted through the through hole. The rear portion of the dust-proof mechanism 9 is accommodated in a space defined by the inner peripheral surface of the tube 231C and the front surface of the bottom 231D.

As shown in fig. 1 and 2, a spring 231E is provided between the main body case 230 and the plunger cover 231. The spring 231E biases the rear portion of the pusher cover 231 downward.

The sliding metal 232A is fixed to the sliding metal arrangement portion 231a of the plunger cover 231, and the sliding metal 232B is fixed to the sliding metal arrangement portion 231B of the plunger cover 231. Through holes 232A and 232B extending in the front-rear direction are formed in the sliding metals 232A and 232B, respectively, and the push rod 7 is inserted through the through holes 232A and 232B. Thus, the pushrod cover 231 supports the pushrod 7 via the sliding metals 232A and 232B so as to be slidable back and forth. As shown in fig. 2, the sliding metal 232B has a cylindrical portion 232C.

The cylindrical portion 232C forms a distal end portion of the sliding metal 232B and has a substantially cylindrical shape extending in the front-rear direction. The outer diameter of the cylindrical portion 232C is substantially the same as the diameter of the inner ring portion of the bearing 233.

The bearing 233 shown in fig. 1 and 2 is provided in the cylindrical portion 232C. Specifically, the inner ring portion of the bearing 233 is fixed to the outer surface of the cylindrical portion 232C, and the outer ring portion of the bearing 233 is configured to be rotatable with respect to the cylindrical portion 232C.

The cover 234 shown in fig. 1 forms a lower portion of the gear housing 23, is formed in a substantially trapezoidal shape in cross section, and is provided so as to protrude downward. The cover 234 is disposed so as to cover the lower portion of the gear portion 6, and supports the lower portion of the gear portion 6.

The switching portion 235 is provided to the main body case 230 so as to be rotatable about an axis extending in the left-right direction, not shown. The cross section of the switching portion 235 perpendicular to the left-right direction is formed in a substantially half-moon shape. The switching unit 235 is configured to be capable of changing its posture between a pressing posture in which the pusher cover 231 and the slide metal 232B are pressed upward and a releasing posture in which the pressing is released. In the present embodiment, the posture of the switching portion 235 with the substantially half-moon-shaped cross section facing substantially forward is the pressing posture (see fig. 7 and 8), and the posture of the switching portion 235 with the substantially half-moon-shaped cross section facing substantially upward is the releasing posture (see fig. 9 and 10). In other words, the state in which the chord portion in the half-moon shape formed by the side-view switching portion 235 extends in the up-down direction is the pressing posture, and the state in which the chord portion in the half-moon shape formed by the side-view switching portion 235 extends in the front-rear direction is the releasing posture.

The front cover 24 shown in fig. 1 extends forward from the front end of the motor housing 21, is formed in a substantially cylindrical shape whose diameter decreases toward the front, and covers substantially the entire outer peripheral surface of the gear housing 23. The front cover 24 is made of an elastic member having high insulating properties and heat insulating properties, such as resin having a high friction coefficient.

The motor 3 shown in fig. 1 is a DC brushless motor, and includes a rotary shaft 31, a pinion gear 32, a rotor 33, a stator 34, a fan 35, and an elastic body 36. The motor 3 is an example of the "driving source" in the present invention.

The rotary shaft 31 extends in the front-rear direction, and is supported by the housing 2 so as to be rotatable about an axis a extending in the front-rear direction and movable in the front-rear direction with respect to the housing 2. The axis a is a line extending in the left-right direction and passing through the axial center of the rotary shaft 31.

The pinion gear 32 is provided integrally with the rotary shaft 31 at the distal end of the rotary shaft 31, and rotates coaxially with the rotary shaft 31.

The rotor 33 has a permanent magnet, and is fixed to the rotary shaft 31 so as to rotate coaxially and integrally with the rotary shaft 31.

The stator 34 is formed in a substantially cylindrical shape extending in the front-rear direction, and has three stator coils connected in a star shape. The stator 34 is fixed to the housing 2 in a state of being accommodated in the cylindrical portion 211 of the motor housing 21.

The fan 35 is fixed to the rotary shaft 31 so as to be rotatable integrally with the rotary shaft 31 behind the pinion gear 32.

The elastic body 36 is an elastically deformable rubber member, and is formed in a substantially cylindrical shape extending in the front-rear direction. In the present embodiment, when the thrust force acting on the rotary shaft 31 becomes very large, the rotary shaft 31 and the member integrally configured with the rotary shaft 31 move rearward, and the elastic body 36 is compressed rearward, so that the impact applied to the rotary shaft 31 and the gear portion 6 can be alleviated. That is, the durability of the rotary shaft 31 and the gear portion 6 against impact can be improved, and damage and deformation of the rotary shaft 31 and the gear portion 6 can be suppressed.

The control board 4 is formed in a substantially ring shape in front view and is provided behind the motor 3. The control board 4 is provided with a hall element for detecting the position of the rotary shaft 31 of the motor 3, six FETs for controlling the motor 3, and the like.

The controller section 5 has a control box 51 and a panel 52.

The control box 51 is formed in a substantially rectangular parallelepiped shape and is disposed in the second connection portion 223 of the handle case 22. The control box 51 houses a control substrate portion (control portion) that selectively outputs drive signals to the six FETs according to the operation of the flip-flop 22A by the user and the signal output from the hall element 41, and controls the rotation direction, the rotation speed, and the like of the motor 3. The control substrate portion is constituted by, for example, a microcomputer and a drive signal output circuit.

The panel 52 is fitted into the peripheral wall of the extension 212 of the motor housing 21 and electrically connected to the control box 51. A display portion that can be visually confirmed by an operator is provided on an end surface of the panel 52 in the extending direction, and the operator can perform work while confirming the remaining battery level display, the cutting speed display, and the like displayed on the display portion.

As shown in fig. 1, the gear portion 6 includes an intermediate shaft 60, a transmission gear portion 61, and a weight portion 62.

The intermediate shaft 60 is formed in a substantially cylindrical shape extending in the up-down direction. The intermediate shaft 60 is supported by the gear housing 23 so as to be rotatable about an axis B extending in the vertical direction by a large-diameter ball bearing and a small-diameter needle bearing. The axis B is a line that is orthogonal to the rotary shaft 31 of the motor 3, extends in the vertical direction, and passes through the axial center of the intermediate shaft 60.

The transmission gear portion 61 has a bevel gear 610, a raceway guide 611, a pin 612, a needle bearing 613, and a coupling 614. The bevel gear 610 has a counterbalance 610A.

The bevel gear 610 is formed in a substantially circular shape in plan view, and meshes with the pinion gear 32 of the motor 3. The bevel gear 610 receives the driving force of the motor 3 and rotates. The bevel gear 610 is fixed to the intermediate shaft 60 by a screw, and is rotatable integrally with the intermediate shaft 60 about the axis B. The bevel gear 610 rotates in a counterclockwise direction in a plan view. The bevel gear 610 is a gear formed by cutting a steel material and having teeth cut. The bevel gear 610 has a counterbalance 610A. The bevel gear 610 is an example of a "gear portion" in the present invention.

The counterbalance 610A is configured to be located on the opposite side of the pin 612 with respect to the axis B in the bevel gear 610. The counterbalance 610A is a weight integrally formed with the other portion of the bevel gear 610, forming a part of the bevel gear 610. In other words, the weight 610A is provided to the bevel gear 610 and can rotate integrally with the bevel gear 610. The weight 610A has a mass greater than the total mass of the portion of the bevel gear 610 other than the weight 610A.

The track guide 611 is provided to be rotatable integrally with the bevel gear 610 about the axis B. The track guide 611 is formed in a substantially circular shape centered on the axis B in a plan view, and has the same outer diameter as the bevel gear 610. In addition, the upper end of the rail guide 611 is formed to be cut by a plane extending in a direction obliquely crossing with respect to the intermediate shaft 60. In other words, the upper end of the rail guide 611 is formed to have an inclination with respect to an imaginary plane extending in parallel with the left-right direction and the front-rear direction.

The upper end of the rail guide 611 is configured to be able to abut against the bearing 233 of the gear housing 23. Specifically, when the switching portion 235 is in the release position, the upper end of the rail guide 611 abuts on the bearing 233, and the rear portion of the plunger cover 231 is supported via the bearing 233. When the bevel gear 610 rotates, the bearing 233 reciprocates in the vertical direction along the shape of the upper end of the raceway guide 611 in accordance with the height of the raceway guide 611 while rotating. The rod cover 231 of the gear housing 23 is vertically swung around the axial center of the swing shaft 231A by the vertical reciprocating movement of the bearing 233. Further, since the spring 231E provided between the main body case 230 and the pusher cover 231 biases the rear portion of the pusher cover 231 downward, the bearing 233 and the upper end surface of the rail guide 611 appropriately come into contact when the switching portion 235 is in the release position, and the blade Q attached to the blade attachment portion 8 can be appropriately moved in a rail manner. When the switching unit 235 is in the pressing posture, the upper end of the rail guide 611 is separated from the bearing 233. Therefore, even if the bevel gear 610 rotates, the position of the bearing 233 in the up-down direction is kept constant. Further, the rail guide 611 is formed with a through hole penetrating the rail guide 611 in the vertical direction at a position eccentric with respect to the axis B.

The pin 612 is formed in a substantially cylindrical shape extending in the up-down direction. The lower portion of the pin 612 is fixed to the bevel gear 610 at a position eccentric with respect to the axis B by press fitting. The upper portion of the pin 612 protrudes in the axis B direction from the upper surface of the bevel gear 610 through the through hole of the rail guide 611.

Needle bearings 613 are provided on the upper portion of the pins 612. In other words, the needle bearing 613 is provided at the protruding end of the pin 612. The needle bearing 613 is rotatable relative to the pin 612.

The connecting member 614 is formed in a substantially cylindrical shape extending in the up-down direction. The needle roller bearing 613 is rotatably provided on the inner peripheral surface of the coupling 614. Thereby, the link 614 is able to rotate relative to the pin 612.

The weight 62 is disposed below the bevel gear 610 so as to vertically face the bevel gear 610 with respect to the axis a of the rotary shaft 31 of the motor 3. The weight 62 has a bevel gear 620 and a weight 620A.

The bevel gear 620 is engaged with the pinion gear 32 at the rear portion thereof, and is configured to be rotatable about the axis B with respect to the intermediate shaft 60 via a bearing. Bevel gear 620 rotates in a clockwise direction when viewed from above. That is, it rotates in the opposite direction as the bevel gear 610. Bevel gear 620 has a number of teeth equal to the number of teeth that bevel gear 610 has.

The weight 620A is a weight integrally formed with the other portion of the weight portion 62, and forms a part of the weight portion 62. The weight 620A has a mass greater than the total mass of the portion of the weight 62 other than the weight 620A.

Here, in the present embodiment, the configuration is such that: the product of the center of gravity of the assembly of the transmission gear portion 61, that is, the bevel gear 610, the raceway guide 611, the pin 612, the needle bearing 613, and the coupling 614 that integrally rotates counterclockwise in plan view (hereinafter referred to as the "center of gravity of the transmission gear portion 61") and the distance between the center of gravity (the center of gravity of the transmission gear portion 61) and the axis B is substantially equal to the product of the center of gravity of the assembly of the weight portion 62, that is, the weight portion 62 that integrally rotates clockwise in plan view (hereinafter referred to as the "center of gravity of the weight portion 62") and the distance between the center of gravity (the center of gravity of the weight portion 62) and the axis B. According to such a configuration, when the transmission gear portion 61 and the weight portion 62 rotate in opposite directions at the same angular velocity, the magnitude of the centrifugal force generated in the transmission gear portion 61 and the magnitude of the centrifugal force generated in the weight portion 62 can be made substantially equal to each other. This can appropriately suppress the reciprocating tool from generating vibration in a direction orthogonal to the reciprocating direction of the push rod 7.

The push rod 7 is interposed between the bevel gear 610 and the blade mounting portion 8 on a transmission path of the driving force of the motor 3. The push rod 7 extends in the front-rear direction, and is supported via a pair of slide metals 232A, 232B disposed at the front and rear portions of the push rod cover 231 so as to be capable of reciprocating in the front-rear direction with respect to the push rod cover 231. Specifically, the push rod 7 reciprocates along the axis C. Here, the axis C is a line passing through the axial center of the push rod 7. The front end portion of the push rod 7 protrudes from the opening 23a to the outside of the gear housing 23. The push rod 7 can swing up and down in accordance with the swing of the push rod cover 231 about the swing shaft 231A. Further, the push rod 7 is provided with a pin guide 71. The push rod 7 is an example of the "driving portion", "driving body", and "driving shaft" in the present invention.

The pin guide 71 is interposed between the bevel gear 610 and the push rod on a transmission path of the rotational force of the motor 3, and converts the rotational motion of the bevel gear 610 into the reciprocating motion of the push rod 7. The pin guide 71 is provided integrally with the push rod 7 at a position rearward of the intermediate portion and forward of the rear end portion in the front-rear direction of the push rod 7. A guide groove 71a extending in the left-right direction and recessed upward is formed in a lower portion of the pin guide 71. The width of the guide groove 71a in the front-rear direction is formed slightly larger than the diameter of the pin 612. The link 614 is connected to the guide groove 71a, and the upper portion of the pin 612 is accommodated in the guide groove 71a so as to be movable in the left-right direction together with the needle roller bearing 613 and the link 614. That is, the movement of the pin 612 in the front-rear direction with respect to the pin guide 71 is restricted, and the movement in the left-right direction is permitted. More specifically, the coupling 614 rotates with respect to the upper portion of the pin 612, whereby the pin 612, the needle roller bearing 613, and the coupling 614 move in the left-right direction in the guide groove 71 a. The pin guide 71 is movable in the vertical direction with respect to the pin 612. The pin guide 71 is an example of the "motion conversion mechanism portion" in the present invention.

The blade attachment portion 8 is provided at the distal end portion of the push rod 7, and is configured to be able to attach a blade Q for cutting a material. The blade mounting portion 8 is capable of reciprocating along the axis C.

Next, the structure of the dust-proof mechanism 9 will be described with reference to fig. 2 to 6. As shown in fig. 2, the dust-proof mechanism portion 9 includes a first dust-proof mechanism 91 and a second dust-proof mechanism 92.

As shown in fig. 3, the first dust-proof mechanism 91 is disposed in the opening 23A of the gear housing 23 and surrounds the outer peripheral surface of the plunger 7. Specifically, the first dust-proof mechanism 91 is provided adjacent to the opening 23 a. As shown in fig. 2 and 3, the first dust-proof mechanism 91 includes a first clamping member 911, a second clamping member 912, and an elastic body 913. The first dust-proof mechanism 91 is an example of the "discharge mechanism portion" and the "holding portion" in the present invention. The first clamping member 911 and the second clamping member 912 are examples of the "support portion" in the present invention.

The first clamping member 911 shown in fig. 2 and 3 is a metal member, and is disposed in the gear housing 23 such that the front surface thereof abuts against the rear surface of the wall of the gear housing 23 in which the opening 23a is formed. The first clamping member 911 has a circular plate portion 911A and an edge portion 911B.

The circular plate portion 911A is formed in a substantially circular shape in a rear view angle. The inner peripheral surface 911A of the disc portion 911A is configured to have a diameter larger than that of the push rod 7, and the push rod 7 is inserted through the inner peripheral surface 911A.

The edge portion 911B forms an outer edge portion of the first clamping member 911, and extends rearward in a cylindrical shape from a radially outer end portion of the disc portion 911A.

The second clamping member 912 is a metal member and has a cylindrical portion 912A and an abutting portion 912B.

The cylindrical portion 912A is formed into a substantially cylindrical shape extending in the front-rear direction. A through hole 912A is formed in a substantially central portion in the radial direction of the cylindrical portion 912A. The through hole 912a has an inner diameter equal to the outer diameter of the plunger 7, and the plunger 7 is inserted into the through hole 912 a. The push rod 7 is capable of reciprocating sliding with respect to the cylindrical portion 912A (second clamping member 912).

The contact portion 912B forms a rear portion of the second clamping member 912 and has a substantially annular shape in a rear view. As shown in fig. 3, the abutting portion 912B is formed to extend radially outward of the cylindrical portion 912A with a predetermined curvature from the rear end of the cylindrical portion 912A toward the rear and then linearly extend radially outward of the cylindrical portion 912A in a side view. The rear surface of the contact portion 912B contacts the front surface of the cylindrical portion 231C of the dust-proof mechanism accommodating portion 231B of the plunger cover 231 and the front surface of the second dust-proof mechanism 92.

The elastic body 913 shown in fig. 4 and 5 has a thickness in the front-rear direction and is formed of an elastic member such as rubber or resin. The elastic body 913 is formed in a rounded shape in the lower and upper directions in the front and rear views. In other words, the elastic body 913 has a substantially rectangular parallelepiped lower portion and a semicircular upper portion having a predetermined curvature. A through hole 913b penetrating in the front-rear direction is formed in a substantially central portion of the elastic body 913. The through hole 913b is inserted with the cylinder portion 912A of the second clamping member 912 and the push rod 7 inserted in the cylinder portion 912A. The elastic body 913 has a main body portion 9130, a first edge portion 913A, a second edge portion 913B, a unidirectional valve portion 913C, a first annular protrusion 913D, a second annular protrusion 913E, and a third annular protrusion 913F. The elastic body 913 is an example of the "elastic member" in the present invention.

The body portion 9130 forms a main body portion of the elastic body 913. As shown in fig. 4(c), 5(a), and 5(B), an annular recessed portion 9130a, which is circular in front view and is recessed rearward from the front surface of the body portion 9130, is formed in the front portion of the body portion 9130. As shown in fig. 4(a), 5(a), and 5(B), an annular recessed portion 9130B, which is circular in rear view and recessed forward from the rear surface of the body portion 9130, is formed in the rear portion of the body portion 9130.

As shown in fig. 4(B), the first edge portion 913A and the second edge portion 913B slightly protrude from the main body portion 9130 of the elastic body 913 radially outward of the through hole 913B. As shown in fig. 4(B), a holding groove 913A recessed radially inward of the through hole 913B is formed by the side surface of the body portion 9130, the first edge portion 913A, and the second edge portion 913B.

The one-way valve portion 913C is configured to allow a fluid (air or oil in the present embodiment) to flow from inside the gear housing 23 to outside the gear housing 23, and to suppress a fluid from flowing from inside the gear housing 23 to inside the gear housing 23. As shown in fig. 5(a), the one-way valve portion 913C has a wall portion 913G and an extending portion 913H. The wall portion 913G is a portion forming a through hole 913b, and is formed in a substantially cylindrical shape extending in the front-rear direction.

The protruding portion 913H is provided in front of the wall portion 913G. The protruding portion 913H protrudes obliquely forward in the radial inward direction of the through hole 913 b. In other words, the protruding portion 913H protrudes toward the axis C of the pushrod 7 and is inclined with respect to the direction orthogonal to the direction of the axis C of the pushrod 7. In a state where no external force acts on the protruding portion 913H, the angle at which the protruding portion 913H tilts forward is an angle α as shown in fig. 5 (a).

As shown in fig. 5, the first annular protrusion 913D is formed in a substantially annular shape in front view, and protrudes forward from the bottom surface forming the annular recessed portion 9130 a. The second annular protrusion 913E is formed in a substantially annular shape in front view, and protrudes forward from the bottom surface forming the annular recessed portion 9130 a. The second annular projection 913E is located radially inward of the through hole 913b than the first annular projection 913D in a front view.

The first annular protrusion 913D and the second annular protrusion 913E protrude from the bottom surface forming the annular recessed portion 9130a, thereby forming a first annular groove 913c and a second annular groove 913D. The first annular groove 913c and the second annular groove 913d each have a substantially annular shape in front view. The second annular groove 913d is formed radially inward of the through hole 913b from the first annular groove 913c in front view. In addition, the second annular groove 913d is filled with oil. In the present embodiment, the oil is a grease having viscosity. That is, the oil in the present embodiment has the property of a non-newtonian fluid, and the fluidity changes depending on the magnitude of the applied stress. The second annular groove 913d is an example of the "groove" in the present invention. Oil is an example of the "fluid" in the present invention.

As shown in fig. 4(a) and (c), the elastic body 913 has a plurality of through holes 913e that penetrate the body portion 9130 in the front-rear direction. In the present embodiment, four through holes 913e are formed. As shown in fig. 4(c), a plurality of through holes 913e are formed at positions overlapping the second annular groove 913 d. Thereby, as shown in fig. 5(B), the plurality of through holes 913e and the second annular groove 913d communicate with each other. Thereby, the oil filled in the second annular groove 913d can flow into the plurality of through holes 913 e.

As shown in fig. 4(a), the third annular projection 913F is formed in a substantially annular shape in the rear view, and projects rearward from the rear surface of the main body portion 9130 (see fig. 5).

Here, the arrangement relationship of the components of the first dust-proof mechanism 91 in the gear housing 23 will be described. As shown in fig. 6, the elastic body 913 is disposed in the gear housing 23 between the first clamping member 911 and the second clamping member 912. In other words, the first clamping member 911 and the second clamping member 912 support the elastic body 913.

Specifically, the elastic body 913 is accommodated in the gear housing 23 such that the first projecting portion 23B of the gear housing 23 is positioned in the holding groove 913a of the elastic body 913. Further, the protruding end portions of the first annular projection 913D and the second annular projection 913E abut against the rear surface of the disc portion 911A of the first clamping member 911. Further, the protruding end of the third annular projection 913F abuts against the front surface of the abutment portion 912B of the second clamping member 912. The lower portion of the elastic body 913 is fitted between the wall of the opening 23A of the gear housing 23 and the second protruding portion 23C. Thereby, the front-rear direction position of the elastic body 913 is positioned.

As shown in fig. 6, the outer peripheral surface of the edge portion 911B of the first clamping member 911 abuts against the inner peripheral surface forming the annular recessed portion 9130 a. Thereby, the vertical position of the elastic body 913 is positioned.

In addition, in a state where the elastic body 913 is disposed in the gear housing 23, the protruding portion 913H of the one-way valve portion 913C is in close contact with the inner circumferential surface of the cylindrical portion 912A of the second sandwiching member 912. In this state, the protruding portion 913H inclines forward at an angle larger than the angle α (see fig. 5 a).

Further, the protruding portion 913H is in close contact with the outer peripheral surface of the cylindrical portion 912A, the first annular protrusion 913D and the second annular protrusion 913E are in contact with the rear surface of the circular plate portion 911A, and the third annular protrusion 913F is in contact with the front surface of the contact portion 912B, thereby defining a space 91A including the second annular groove 913D and the plurality of through holes 913E, and in which communication with the outside of the first dust-proof mechanism 91 is blocked at least in a state where no external force is applied. In the present embodiment, the air intake portion 91A that allows air (fluid) to flow into the space 91A when a predetermined external force acts on the first dust-proof mechanism 91 is formed by the contact portion 912B of the second clamping member 912 and the third annular protrusion 913F. The air intake portion 91A and the one-way valve portion 913C are separated. The space 91a is an example of the "space" in the present invention. The air intake section 91A is an example of the "air intake section" and the "suction section" in the present invention. Air is one example of the "fluid" in the present invention.

As shown in fig. 2, the second dust prevention mechanism 92 includes a first holding member 921, a second holding member 922, an annular member 923, and an O-ring 924. The second dust-proof mechanism 92, the first holding member 921, and the second holding member 922 are examples of the "holding portion" in the present invention. The annular member 923 and the O-ring 924 are examples of the "sealing portion" in the present invention.

The first holding member 921 is formed of an elastic member such as rubber or resin, and has a substantially cylindrical shape extending in the front-rear direction. As shown in fig. 6, the first holding member 921 is provided with an annular projection 921A.

The annular projection 921A forms a substantially annular projection in front view. In the present embodiment, a plurality of annular projections 921A are provided on the outer peripheral surface of the first holding member 921, and a plurality of annular projections are provided on the front surface of the first holding member 921. The first holding member 921 is press-fitted into the dust-proof mechanism accommodating portion 231B of the plunger cover 231. Specifically, the annular projection 921A of the first holding member 921 on the outer peripheral surface abuts against the inner peripheral surface of the tube portion 231C of the dust-proof mechanism housing portion 231B to generate a pressing force, the annular projection 921A of the first holding member 921 on the front surface abuts against the rear surface of the abutment portion 912B of the second clamping member 912 to generate a pressing force, and the rear surface of the first holding member 921 abuts against the front surface of the second holding member 922 to fix the first holding member 921 to the push rod cover 231. That is, the first holding member 921 is positioned with respect to the push rod cover 231 which is a part of the gear housing 23.

Further, a through hole 921c that penetrates the first holding member 921 in the front-rear direction is formed in a substantially central portion of the first holding member 921 in the radial direction. The diameter of the through hole 921c is larger than the diameter of the plunger 7, and the plunger 7 is inserted into the through hole 921 c.

In addition, an annular member accommodating portion 921a that is recessed radially outward of the first holding member 921 from the inner circumferential surface of the first holding member 921 and accommodates the annular member 923 is formed in the front portion of the first holding member 921. Further, an O-ring housing section 921b that is recessed radially outward of the first holding member 921 from the inner circumferential surface of the first holding member 921 and houses the O-ring 924 is formed in the rear portion of the first holding member 921. The through hole 921c, the annular member housing section 921a, and the O-ring housing section 921b communicate in the front-rear direction.

The second holding member 922 is formed of an elastic member such as rubber or resin, and has a substantially cylindrical shape extending in the front-rear direction. The second holding member 922 is provided with an annular projection 922A.

The annular protrusion 922A forms a substantially annular protrusion in a rear view. In the present embodiment, one annular protrusion 922A is provided on each of the outer peripheral surface and the rear surface of the second holding member 922. The second holding member 922 is press-fitted into the dust-proof mechanism accommodating portion 231B of the plunger cover 231. Specifically, the annular projection 922A of the second holding member 922 on the outer peripheral surface abuts against the inner peripheral surface of the tube portion 231C of the dust-proof mechanism housing 231B to generate a pressing force, the annular projection 922A of the second holding member 922 on the rear surface abuts against the front surface of the bottom portion 231D of the dust-proof mechanism housing 231B to generate a pressing force, and the front surface of the second holding member 922 abuts against the rear surface of the first holding member 921 to fix the second holding member 922 to the pusher cover 231. That is, the second holding member 922 is positioned with respect to the push rod cover 231 that is a part of the gear housing 23.

The second holding member 922 has a curved surface 922B. The curved surface 922B has a predetermined curvature, and faces and protrudes toward the outer peripheral surface of the plunger 7. By thus curving the surface of the second holding member 922 facing the outer peripheral surface of the plunger 7, when the second holding member 922 is pressed rearward from the O-ring 924 and deformed, contact between the second holding member 922 and the plunger 7 can be appropriately suppressed, and the second holding member 922 can be appropriately deformed. A through hole 922B penetrating the second holding member 922 in the front-rear direction is predetermined by the curved surface 922B. The diameter of the through hole 922b in the substantially central portion of the second holding member 922 in the front-rear direction is configured to be larger than the diameter of the plunger 7, and the plunger 7 is inserted into the through hole 922 b. The curved surface 922B is an example of the "curved surface" in the present invention.

Further, the second holding member 922 is formed with a lubricant oil accommodating portion 922 a. The oil receiver 922a is recessed rearward from the front surface of the second holding member 922 and is formed in a substantially annular shape in front view. In a state where no external force acts on the second dust-proof mechanism or the external force is small, the lubricating oil accommodating portion 922a and the O-ring accommodating portion 921b of the first holding member 921 are not communicated. That is, when the external force applied to the second dust-proof mechanism is sufficiently small, the lubricant oil container 922a forms a closed space, and the lubricant oil is held in the space. Further, the lubricant oil container 922a does not necessarily need to be completely closed, and may be configured to suppress outflow of the lubricant oil. In the present embodiment, the lubricating oil is grease. Lubricating oil is an example of "lubricant" and "fluid" in the present invention. The lubricant oil container 922a is an example of the "lubricant oil container" in the present invention.

The first and second holding members 921, 922 constitute holding portions that surround the annular member 923 and the O-ring 924, support the annular member 923 and the O-ring 924 in contact with the outer peripheral surface of the push rod 7, and contain lubricating oil.

In the present embodiment, the annular member 923 is formed of a felt containing oil. The annular member 923 is formed in an annular shape having a thickness in the front-rear direction, and is accommodated in an annular member accommodation portion 921a formed in the first holding member 921. The annular member 923 is held in contact with the outer peripheral surface of the push rod 7 by the first holding member 921. The annular member 923 surrounds the outer peripheral surface of the push rod 7 and seals the outer peripheral surface of the push rod 7. The front surface of the annular member 923 abuts against the rear surface of the abutting portion 912B of the second clamping member 912 of the first dust-proof mechanism 91. A through hole 923a that penetrates the annular member 923 in the front-rear direction is formed in a substantially central portion of the annular member 923 in the radial direction. The through hole 923a has an inner diameter equal to the outer shape of the push rod 7, and the push rod 7 is inserted into the through hole 923 a. By providing the felt as the annular member 923 in this manner, even when high-temperature iron powder, liquid, or the like enters from the opening 23a of the gear housing 23, deformation of the O-ring 924 and the like can be suppressed, and deterioration in dust-proof performance and water-proof performance can be suppressed. Further, since the felt of the annular member 923 is impregnated with oil, the slidability of the O ring 924 and the push rod 7 can be improved.

The O-ring 924 is formed of an elastic member such as rubber or resin. The O-ring 924 is accommodated in an O-ring accommodation portion 921b formed in the first holding member 921. The O-ring 924 surrounds the outer circumferential surface of the plunger 7 and seals the outer circumferential surface of the plunger 7. O-ring 924 is formed as an annulus. The inner peripheral surface 924a of the O-ring 924 is formed with an inner diameter slightly smaller than the outer shape of the plunger 7. By elastically deforming the O-ring 924, the push rod 7 is inserted through the inner peripheral surface 924 a. At this time, the O-ring 924 is brought into close contact with the outer peripheral surface of the plunger 7 by its elasticity. This improves the sealing property with the outer periphery of the push rod 7. Grease is applied in advance to the contact surface between the O ring 924 and the plunger 7, and the plunger 7 can slide back and forth relative to the O ring 924 as appropriate until the grease is dried.

Next, the operation of cutting a material to be cut (for example, a metal pipe) using the saw blade 1 of the present embodiment and the operation of the saw blade 1 during the cutting operation will be described with reference to fig. 7 to 10.

When performing the cutting work, the operator mounts the blade Q on the blade mounting portion 8 and presses the base 23D against the material to be cut. In this state, when the trigger 22A is operated to toggle, the control unit accommodated in the control box 51 controls the six FETs, and the electric power of the battery pack P is supplied to the motor 3, so that the motor 3 starts driving. When the motor 3 starts driving, the rotary shaft 31 and the pinion gear 32 rotate, and the bevel gear 610 meshing with the pinion gear 32 starts rotating around the axis B extending in the vertical direction. By the rotation of the bevel gear 610, the pin 612 performs a circling motion centering on the axis B. Only the forward-backward component of the circling motion of the pin 612 is transmitted to the pin guide 71, and the push rod 7, the pin guide 71, the blade mounting portion 8, and the blade Q mounted on the blade mounting portion 8 reciprocate in the axis C direction integrally between a state (referred to as a forward position in the following description, see fig. 7 and 9) in which each is positioned at the forefront and a state (referred to as a backward position in the following description, see fig. 8 and 10) in which each is positioned at the rearmost.

At the same time, bevel gear 610 is driven by pinion gear 32 which meshes. Since the bevel gear 610 and the weight 62 have the same number of teeth, the weight 62 rotates at the same magnitude of angular velocity in the opposite direction of the bevel gear 610. As the bevel gear 610 and the weight portion 62 rotate, the center of gravity of the transmission gear portion 61 and the center of gravity of the weight portion 62 rotate in opposite directions around the axis B at the same angular velocity, and perform circular motion.

Here, when the switching portion 235 is in the pressing posture, the switching portion 235 presses the rear portion of the pusher cover 231 upward, and the upper end of the rail guide 611 and the bearing 233 are maintained in a separated state. Thus, the push rod cover 231 and the push rod 7 do not swing about the swing shaft 231A. In other words, when the switch 235 is in the pressing posture, the axis C passing through the axial center of the plunger 7 is maintained in a state of being inclined at a predetermined angle with respect to the front-rear direction (horizontal axis O), and the plunger 7 reciprocates in the front-rear direction along the axis C.

On the other hand, when the switching portion 235 is in the release posture, the outer ring portion of the bearing 233 contacts the upper end of the rail guide 611 while rotating, and reciprocates in the vertical direction in accordance with the shape of the upper end of the rail guide 611. The vertical reciprocating movement of the bearing 233 causes the rod cover 231 and the rod 7 of the gear housing 23 to swing vertically about the axial center of the swing shaft 231A. Therefore, the blade Q during the cutting operation cuts the workpiece while performing an elliptical motion, so-called orbital motion (see fig. 11), in a left-right side view. This makes the blade Q strongly intrude into the work material when moving backward, thereby improving the work efficiency. Further, in order to secure a space in which the push rod 7 swings, the inner peripheral surface of the opening 23a is separated from the push rod 7.

Next, an effect achieved by providing the first dust-proof mechanism 91 in the blade saw 1 of the present embodiment will be described with reference to fig. 11 to 15. Here, fig. 11 is a diagram schematically showing the behavior of the tip end (indicated by a black dot in fig. 11) of the push rod 7 with respect to the main body case 230 of the gear housing 23 during the work in the state where the switching portion 235 is in the release posture, and the horizontal axis O is a line parallel to the front-rear direction.

When the front end of the push rod 7 is located at (i) shown in fig. 11, the axis C is parallel to the horizontal axis O as shown in fig. 12. From this state, the tip of the pusher 7 ascends and descends as it goes forward as indicated by the arrow from (i) to (ii) in fig. 11.

Fig. 13 is a view corresponding to fig. 11 (ii), and shows a state of the dust-proof mechanism 9 and its peripheral portion in a case where the tip of the plunger 7 is lowered with respect to the main body case 230. Here, the tip of the push rod 7 moves up and down as the push rod 7 swings about the swing shaft 231A of the push rod cover 231. When the tip of the push rod 7 is lowered as shown in fig. 12, the rear portion of the push rod 7 is raised upward, and an axis C passing through the axis of the push rod 7 is inclined with respect to the horizontal axis O. At this time, the second clamping member 912 and the plunger cover 231 into which the plunger 7 is inserted also swing integrally with the plunger 7. In the process from fig. 12 to fig. 13 (the process from (i) to (ii) of fig. 11), the push rod 7, the push rod cover 231, and the second clamp member 912 are swung in the clockwise direction of fig. 12 and fig. 13 with respect to the main body housing 230.

In this state, the cylindrical portion 912A of the second clamping member 912 is pressed rotationally clockwise from the outer periphery of the push rod 7 at the upper portion of the first dust-proof mechanism 91, and the rear portion of the wall portion 913G of the one-way valve portion 913C of the elastic body 913 is pressed upward. Further, the contact portion 912B of the second clamping member 912 is rotated in the clockwise direction, and is pressed forward by the front end surface of the dust-proof mechanism accommodating portion 231B of the plunger cover 231 rotated in the clockwise direction, so that the rear portion of the elastic body 913 is pressed forward while being in contact with the third annular protrusion 913F of the elastic body 913. Thereby, the elastic body 913 is elastically deformed, and the volume of the space 91a is reduced. As the volume of the space 91a decreases, the pressure in the space 91a starts to rise.

Further, in the lower portion of the first dust-proof mechanism 91, the cylindrical portion 912A of the second sandwiching member 912 receives a clockwise-rotating pressing force from the outer periphery of the push rod 7, and presses the front portion of the wall portion 913G of the one-way valve portion 913C of the elastic body 913 downward. Thereby, the elastic body 913 is elastically deformed, and the volume of the space 91a is reduced. As the volume of the space 91a decreases, the pressure in the space 91a starts to rise.

From this state, when the tip of the push rod 7 is further lowered with respect to the main body case 230 as shown in fig. 14 (fig. 11 (iii)), the cylindrical portion 912A of the second clamping member 912 presses the rear portion of the wall portion 913G of the one-way valve portion 913C of the elastic body 913 further upward and the abutting portion 912B presses the rear portion of the elastic body 913 further forward in the upper portion of the first dust-proof mechanism 91. Further, the cylindrical portion 912A presses the front portion of the wall portion 913G further downward below the first dust-proof mechanism 91. Thereby, the elastic body 913 is further elastically deformed, and the volume of the space 91a is further reduced. As the volume of the space 91a decreases, the pressure in the space 91a further rises.

At this time, the pressure in the space 91a becomes higher than the predetermined value, and the air in the space 91a and the oil filled in the second annular groove 913d are discharged from the one-way valve portion 913C through the through hole 913 e. Specifically, when the pressure is higher than the predetermined value, the projecting portion 913H of the one-way valve portion 913C rotates clockwise, and a gap is formed between the projecting portion 913H and the outer peripheral surface of the cylindrical portion 912A. Air or oil (or both) is discharged from the gap. Immediately after the air or oil is discharged, the protruding portion 913H rotates counterclockwise and comes into close contact with the outer peripheral surface of the cylindrical portion 912A again. This can suppress the intrusion of dust into the space 91 a.

In this way, the first dust-proof mechanism 91 deforms in response to an external force caused by the driving of the push rod 7, and discharges air and oil to the outside of the housing 2. Thus, even if dust is intended to enter the housing 2 through the opening 23a during operation (driving of the push rod 7), the air and oil (grease) discharged to the outside through the opening 23a effectively suppress the intrusion of dust, and therefore, the intrusion of dust generated during operation into the housing 2 can be appropriately suppressed. In particular, although the opening 23a is slightly opened to secure the swing range of the push rod 7 by the track mechanism, dust may enter the opening 23a, oil (grease) is fed to the opening 23a, and the oil (grease) is stored in the opening 23a and a space around the opening 23a, as if the opening 23a is covered (sealed). Accordingly, since the oil (grease) having a high viscosity flows in accordance with the oscillation of the plunger 7 and blocks the opening 23a, the intrusion of dust into the housing 2 can be more effectively suppressed. As described above, according to the configuration of the present embodiment, oil (grease) can be used as the sealing material corresponding to the opening 23a opened for the track mechanism, and thus the intrusion of dust into the housing 2 can be suppressed.

Further, as described above, the one-way valve portion 913C allows air to flow from the inside of the housing 2 to the outside of the housing, and suppresses air from flowing from the outside of the housing 2 to the inside of the housing 2. This can appropriately suppress the intrusion of dust generated during operation into the housing 2.

Further, the one-way valve portion 913C discharges air and oil in the space 91a to the outside of the housing 2 as the elastic body 913 deforms in response to an external force to reduce the volume of the space 91a, and therefore, intrusion of dust generated during operation into the housing 2 can be appropriately suppressed.

As shown in fig. 15 (fig. 11 (iv)), when the front end of the plunger 7 rises from below, the plunger 7, the plunger cover 231, and the second clamp member 912 integrally swing in the counterclockwise direction in fig. 14. At this time, in the upper portion of the first dust-proof mechanism 91, the upward pressing of the cylindrical portion 912A of the second sandwiching member 912 against the rear portion of the wall portion 913G of the one-way valve portion 913C of the elastic body 913 and the pressing of the abutting portion 912B against the rear portion of the elastic body 913 are relaxed. Further, in the lower portion of the first dust-proof mechanism 91, the cylindrical portion 912A alleviates downward pressure on the front portion of the wall portion 913G of the one-way valve portion 913C of the elastic body 913. Thereby, the elastic body 913 is elastically deformed so as to restore the elastic body, and the volume of the space 91a is increased. As the volume of the space 91a increases, the pressure in the space 91a becomes smaller.

At this time, when the pressure in the space 91A is less than a predetermined value, air flows in from the air intake portion 91A. Specifically, the contact between the front surface of the contact portion 912B of the second clamping member 912 and the third annular protrusion 913F of the elastic body 913 is released, and the air in the main body case 230 flows into the first dust prevention mechanism 91 through the gap generated thereby. At this time, the protruding portion 913H of the one-way valve portion 913C is in close contact with the outer peripheral surface of the cylindrical portion 912A, and therefore, the intrusion of dust into the main body case 230 through the one-way valve portion 913C can be suppressed.

Next, the effect achieved by providing the second dust-proof mechanism 92 in the blade saw 1 of the present embodiment will be described in detail with reference to fig. 16 to 20. Since the second dust-proof mechanism 92 is effective by the reciprocating movement of the push rod 7 in the front-rear direction, the inclination of the axis C of the push rod 7 with respect to the horizontal axis O during operation is omitted in fig. 16 to 20. It is understood by those skilled in the art that the same effects as those described below in the present embodiment can be obtained even if the push rod 7 is swung in the vertical direction about the swing shaft 231A of the push rod cover 231.

As described above, since the grease is applied to the contact surface between the O ring 924 and the push rod 7 in advance, the push rod 7 can slide back and forth substantially in a proper manner with respect to the O ring 924 accommodated in the O ring accommodation portion 921b of the first holding member 921.

However, if the amount of oil (grease) applied in advance is reduced or eliminated by a continuous operation or the like, friction between the O-ring 924 and the plunger 7 may increase, and the O-ring 924 may be easily worn. When this state is left, the O-ring 924 may be damaged early, and the dust resistance may be lowered.

In the present embodiment, when the plunger 7 and the blade attachment portion 8 move rearward as shown in fig. 17 from the state in which the plunger 7 and the blade attachment portion 8 are located at the forward position shown in fig. 16, the O-ring 924 moves rearward integrally with the plunger 7 due to a frictional force generated between the outer peripheral surface of the plunger 7 and the O-ring 924. That is, the O-ring 924 is moved in the plunger cover 231 by power from the plunger 7.

In this state, since the second holding member 922 is positioned with respect to the pusher cover 231, the O-ring 924 presses the radially inner front surface of the second holding member 922 rearward with a predetermined pressing force. At this time, the second holding member 922 is elastically deformed.

From this state, when the pusher 7 and the blade mounting portion 8 are further moved rearward to be positioned at the rear position as shown in fig. 18 and 19, the second holding member 922 is further elastically deformed from the state shown in fig. 17. Fig. 19, which is an enlarged view, shows the manner of elastic deformation of the second holding member 922 in more detail. At this time, the lubricating oil accommodating portion 922a of the second holding member 922 communicates with the O-ring accommodating portion 921b, the through hole 921c, and the annular member accommodating portion 921a of the first holding member 921. In other words, a passage is formed that communicates the lubricant oil accommodating portion 922a and the outer periphery of the push rod 7. Further, due to the movement of the O-ring 924, a part of the lubricant oil accommodating portion 922a holding the lubricant oil is elastically deformed. As a result, since a force is applied to the lubricating oil held in the lubricating oil accommodating portion 922a, the lubricating oil having high viscosity can be moved to the outer periphery of the push rod 7. As the O-ring 924 is moved by the push rod 7 in this way, a passage is formed that communicates the lubricating oil accommodating portion 922a with the outer periphery of the push rod 7, and since a part of the lubricating oil accommodating portion 922a that holds lubricating oil is elastically deformed, lubricating oil is supplied to the O-ring accommodating portion 921b and the annular member accommodating portion 921a in a moving (flowing) manner. Then, the lubricating oil supplied to the O-ring housing 921b adheres to the contact surface between the O-ring 924 and the push rod 7. Thereby, the push rod 7 can appropriately slide back and forth with respect to the O-ring 924. Further, lubricating oil is also supplied to the annular member 923 housed in the annular member housing section 921a, and the sliding property between the O ring 924 and the push rod 7 can be effectively improved. In the present embodiment, the lubricating oil is configured to be appropriately moved by combining two points, that is, a point forming a passage that communicates the lubricating oil containing portion 922a with the outer periphery of the push rod 7 and a point at which a part of the lubricating oil containing portion 922a that holds the lubricating oil is elastically deformed. That is, a passage for communicating the lubricant oil container 922a with the outer periphery of the push rod 7 may be formed or enlarged by an external force from the push rod 7 serving as a drive shaft. In this case, even when the lubricant oil container 922a is not elastically deformed, the lubricant oil having a small viscosity can move to the outer periphery of the plunger 7 by its fluidity. Further, at least a part of the lubricating oil reservoir 922a for storing lubricating oil may be elastically deformed by an external force from the push rod 7. In this case, even if there is no change in the passage that communicates the lubricant oil reservoir 922a with the outer periphery of the plunger 7, the lubricant oil can be moved to the outer periphery of the plunger 7 by the force transmitted by the elastic deformation.

Thereafter, as shown in fig. 20, when the plunger 7 and the blade mounting portion 8 move forward, the elastic force of the second holding member 922, which is intended to return to the original shape, presses the O-ring 924 forward, and returns to the state of being positioned in the O-ring housing section 921b of the first holding member 921.

As described above, since the O ring 924 presses the second holding member 922 with the driving of the push rod 7 and the lubricant is supplied between the O ring 924 and the outer peripheral surface of the push rod 7, the deterioration (abrasion) of the O ring 924 can be suppressed. This can appropriately suppress the intrusion of dust generated during operation into the housing 2. In particular, since the lubricant can be supplied at a timing when the lubricant around the O ring 924 is insufficient, an appropriate amount of lubricant can be supplied to the periphery of the O ring 924 at an appropriate timing.

Next, a blade saw 100 as an example of a power tool according to a second embodiment of the present invention will be described with reference to fig. 21 to 23. The dicing saw 100 basically has the same configuration as the dicing saw 1 of the first embodiment, and the same configuration as the dicing saw 1 is given the same reference numerals and appropriately omitted from description, and mainly different configurations and configurations to be described in more detail will be described. In addition, the same structure as the blade saw 1 achieves the same effects as those described above.

As shown in fig. 21, the knife saw 100 according to the second embodiment includes a second dust prevention mechanism 192 instead of the second dust prevention mechanism 92. The second dust prevention mechanism 192 has a first retainer member 1921 and a second retainer member 1922. Unlike the second holding member 922 of the knife saw 1 of the first embodiment, the second holding member 1922 is not provided with the lubricant oil receiver 922 a. Other configurations are the same as the second holding member 1922 in the second holding member 1922, and therefore, further description of the second holding member 1922 is omitted.

The first holding member 1921 is formed with a lubricant oil reservoir 1921 d. Further, the first holding member 1921 has the same structure as the first holding member 921 of the blade saw 1 according to the first embodiment except that the lubricant oil accommodating portion 1921d is formed, and therefore, further description of the structure of the first holding member is omitted.

According to the above configuration, as shown in fig. 22 and 23, when the plunger 7 and the blade mounting portion 8 move forward, the O-ring 924 moves rearward integrally with the plunger 7 due to the frictional force generated between the outer peripheral surface of the plunger 7 and the O-ring 924.

In this state, the first retaining member 1921 is positioned with respect to the plunger cover 231, and therefore the O-ring 924 presses the radially inner rear surface of the first retaining member 1921 forward with a predetermined pressing force. At this time, the first holding member 1921 is elastically deformed, and the lubricant oil accommodating portion 1921d of the first holding member 1921 communicates with the O-ring accommodating portion 921b, the through hole 1921c, and the annular member accommodating portion 1921 a. Thus, the lubricant oil accommodated in the lubricant oil accommodating portion 1921d is supplied to the O-ring accommodating portion 1921b and the annular member accommodating portion 1921 a. Specifically, lubricating oil is supplied to the contact surface between the O ring 924 and the push rod 7, so that the push rod 7 can appropriately reciprocate with respect to the O ring 924. Further, lubricating oil is also supplied to the annular member 923 housed in the annular member housing portion 1921a, and the slidability between the O ring 924 and the push rod 7 can be effectively improved.

As described above, as the push rod 7 is driven, the O ring 924 presses the first holding member 1921, and lubricating oil is supplied between the O ring 924 and the outer peripheral surface of the push rod 7, so that deterioration (wear) of the O ring can be suppressed. This can appropriately suppress the intrusion of dust generated during operation into the housing 2.

The present invention has been described above based on embodiments. The present embodiment is an example, and those skilled in the art will understand that various modifications are possible in combination of these respective components, and such modifications are also within the scope of the present invention.

In the present embodiment, the reciprocating push rod 7 is used as the drive shaft, but a rotary shaft for rotary driving may be used as the drive shaft. That is, the external force may be transmitted to the holding portion containing the fluid (air or lubricant oil) by the rotating shaft, and the fluid may be discharged to the outside of the holding portion.

In the present embodiment, the power tool and the knife saw have been described as an example, but the present invention can also be applied to a power tool driven by a motor other than a knife saw, for example, a power tool such as a wire saw, a reciprocating saw, a hammer, or a hammer drill.

Description of the symbols

1-knife saw, 2-shell, 3-motor, 4-control substrate, 5-controller portion, 6-gear portion, 7-push rod, 8-blade mounting portion, 9-dustproof mechanism portion.