JP2022127935A - impact tool - Google Patents

Abstract

To improve heat radiation performance against heat generated due to sliding between components in an impact tool.SOLUTION: A movable support 18 at least partially supports a final output shaft 31 and a driving mechanism 5 and is configured to be movable integrally with a motor 2 in an axial direction of a driving axis A1. A biasing member biases the movable support forward in the axial direction. At least one guide shaft extends in the axial direction and is configured to guide axial movement of the movable support in a slidable manner. A metallic member 15 is disposed so as to be able to radiate heat. At least one elastic member has heat conductivity and is disposed so as to contact with the movable support and the metallic member constantly regardless of the position of the movable support in the axial direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to an impact tool configured to linearly drive a tip tool.

A hammer drill is configured to be capable of performing a hammering operation in which a tip tool attached to a tool holder is linearly driven along a drive axis and a drill operation in which the tool is rotationally driven around the drive axis. Generally, for hammering action, a motion conversion mechanism is employed that converts the rotary motion of the intermediate shaft into linear motion, and for drilling action, a rotation mechanism that transmits rotation to the tool holder via the intermediate shaft is employed. A transmission mechanism is employed. Hammer drills of this type receive a reaction force from the workpiece against the impact force of the tip tool when performing a hammering operation. This reaction force mainly generates vibration in the direction in which the drive axis extends (hereinafter also referred to as the axial direction). This vibration will be transmitted to the hammer drill housing and thus to the user.

Patent Document 1 below discloses a structure for absorbing such vibrations. Specifically, a holding member holding a drive mechanism for performing a hammering action is configured to be slidably movable relative to the housing along the guide shaft. The holding member is biased forward (that is, in the direction in which the impact force is applied to the workpiece) by the biasing member. When the tool bit receives a reaction force due to the hammering operation, the reaction force causes the driving mechanism and the holding member to relatively move rearward with respect to the housing together with the tool bit. At this time, the biasing member is elastically deformed, and a part of the reaction force is buffered. This damping action reduces the vibration transmitted to the housing due to the reaction force.

Japanese Patent No. 6322560

However, the hammer drill of Patent Literature 1 does not have a structure capable of appropriately dissipating heat generated as the holding member slides. For this reason, there is concern about early deterioration of the lubricant and deterioration of the durability of the device due to heat generation. This kind of problem is not limited to hammer drills, but rather various impact drills in which a holding member that holds a drive mechanism for performing a hammering operation is configured to be slidably movable relative to a housing along a guide shaft. Common to tools.

SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to improve the heat dissipation property of an impact tool against heat generated by sliding between parts.

According to one aspect of the invention, a final output shaft, a motor, a drive mechanism, a movable support, a biasing member, at least one guide shaft, a metallic member, at least one elastic member, There is provided an impact tool comprising:

A final output shaft is configured to removably retain an accessory tool. The final output shaft also defines the drive axis of the tip tool. The motor has a motor shaft. The drive mechanism is configured to linearly drive the tool bit along the drive axis by the power of the motor. A movable support at least partially supports the final output shaft and the drive mechanism. Also, the movable support is configured to be integrally movable with respect to the motor in the axial direction of the drive axis. The biasing member biases the movable support toward the front side in the axial direction when the side on which the final output shaft is arranged in the axial direction is defined as the front side and the side on which the motor is arranged is defined as the rear side. . At least one guide shaft extends axially and is configured to slidingly guide axial movement of the movable support. The metal member is arranged so as to be capable of dissipating heat. At least one elastic member has thermal conductivity. Also, the at least one elastic member is arranged so as to always be in contact with the movable support and the metal member regardless of the axial position of the movable support.

According to the impact tool of this aspect, at least one thermally conductive elastic member is in constant contact with the movable support and the metal member disposed so as to be capable of dissipating heat. Therefore, the heat generated by the sliding for guiding the movement of the movable support can be transferred from the movable support to the metal member via at least one elastic member and radiated. Therefore, it is possible to improve the heat radiation property against the heat generated by the sliding for guiding the movement of the movable support.

In one aspect of the present invention, the metal member may be arranged so as to be at least partially exposed to the outside of the impact tool. According to this aspect, the heat transferred from the movable support to the metal member can be dissipated with a simple configuration. In this aspect, the metal member may be part of a housing that defines the outer shell of the impact tool.

In one aspect of the invention, the impact tool may include a fan fixed to the motor shaft. A metal member may be positioned on or adjacent to the passageway of the airflow generated by the rotation of the fan. According to this aspect, the heat transferred from the movable support to the metal member can be efficiently dissipated by using the airflow generated by the rotation of the fan.

In one aspect of the invention, the at least one elastic member may be retained on the metal member. The movable support may be configured to slide on the at least one elastic member as the movable support moves axially. According to this aspect, it is possible to easily realize an aspect in which at least one elastic member is always in contact with the movable support and the metal member.

In one aspect of the present invention, at least one elastic member and the movable support may be maintained in a fitted state at all times. According to this aspect, the contact area between the at least one elastic member and the movable support increases compared to the case where the at least one elastic member and the movable support are in planar contact. Therefore, the ability to transfer heat from the movable support to the at least one elastic member is enhanced, and heat dissipation can be improved.

In one aspect of the present invention, the at least one elastic member and the movable support are fitted together in such a manner that a cylindrical shape and a columnar or cylindrical shape are fitted together. The member and movable support may be shaped. According to this aspect, it is possible to obtain a large contact area between the at least one elastic member and the movable support, and at the same time, facilitate manufacturing.

In one aspect of the invention, at least one elastic member may be positioned adjacent to at least one guide shaft. According to this aspect, it is possible to shorten the heat transfer distance from the portion of the movable support where heat is generated due to sliding to the at least one elastic member. Therefore, efficient heat dissipation becomes possible.

In one aspect of the present invention, the at least one elastic member axially abuts the movable support when the movable support moves toward the rear side in the axial direction, and further moves toward the rear side of the movable support. may function as a stopper that regulates the movement of the According to this aspect, the elastic deformation of the at least one elastic member when functioning as a stopper buffers part of the reaction force received from the workpiece due to the hammering action of the tip tool. Therefore, the low vibration property of the impact tool can be enhanced. Also, the durability of the device is improved.

In one aspect of the invention, the at least one guide shaft may comprise multiple guide shafts. The at least one elastic member may comprise a plurality of elastic members corresponding to the plurality of guide shafts. The at least one guide shaft and the at least one elastic member are arranged such that each of the plurality of guide shafts and the corresponding elastic member (which may be one or more) on an imaginary plane orthogonal to the drive axis line. ) and may be arranged such that the distances between them are equal to each other. According to this aspect, since the distances between each of the plurality of guide shafts and the corresponding elastic member (that is, the distance of the heat transfer path) are equal to each other, the occurrence of temperature unevenness in the movable support is suppressed, Uniform heat dissipation is possible.

In one aspect of the invention, the metal member may have at least one hole. At least one elastic member may be retained within the at least one aperture in a fitted manner. According to this aspect, the contact area between the at least one elastic member and the metal member increases compared to the case where the at least one elastic member and the metal member are in planar contact. Therefore, the ability to transfer heat from the at least one elastic member to the metal member is enhanced, and heat dissipation can be improved. Furthermore, the at least one elastic member can be easily attached to and detached from the metal member. Therefore, manufacturing is facilitated, and replacement work is facilitated when at least one elastic member is deteriorated or worn.

1 is a cross-sectional view of a hammer drill according to one embodiment of the invention; FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1; FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2; FIG. FIG. 3 is a cross-sectional view taken along line IV-IV of FIG. 2; FIG. 3 is a cross-sectional view taken along line VV of FIG. 2; FIG. 3 is a cross-sectional view taken along line VI-VI of FIG. 2; FIG. 3 is a cross-sectional view along line VII-VII of FIG. 2, with the movable support in its most forward position; FIG. 3 is a cross-sectional view along line VII-VII of FIG. 2, with the movable support in the rearmost position; FIG. 3 is a cross-sectional view along line IX-IX of FIG. 2, with the movable support in its most forward position; FIG. 3 is a cross-sectional view along line IX-IX of FIG. 2, with the movable support in its most forward position; Fig. 3 is a perspective view of a first support; Fig. 3 is a perspective view of a movable support; FIG. 4 is a perspective view of a second support; FIG. 4 is a perspective view of a second support;

An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, a hammer drill 101 is exemplified as an example of an impact tool. The hammer drill 101 is a hand-held power tool used for machining operations such as chipping and drilling, and performs an operation of linearly driving the tip tool 91 along a predetermined drive axis A1 (hereinafter referred to as hammer operation). , and the operation of rotationally driving the tip tool 91 around the drive axis A1 (hereinafter referred to as drill operation).

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

The body housing 10 is a hollow body that is also called a tool body or an outer shell housing, and accommodates the spindle 31, the motor 2, the drive mechanism 5, and the like. The spindle 31 is an elongated cylindrical member, and has a tool holder 32 that detachably holds the tip tool 91 at one axial end thereof. The long axis of spindle 31 defines drive axis A1 of tip tool 91 . The body housing 10 extends along the drive axis A1. The tool holder 32 is arranged within one end of the main body housing 10 in the extending direction of the drive axis A1 (hereinafter also simply referred to as the axial direction).

The handle 17 is an elongated hollow body that is gripped by the user. One axial end of the handle 17 is connected to the other axial end of the body housing 10 (the end opposite to where the tool holder 32 is arranged). The handle 17 protrudes from the other end of the main body housing 10 and extends in a direction intersecting (more specifically, a direction generally orthogonal to) the drive axis A1. In this embodiment, the body housing 10 and the handle 17 are integrated by connecting a plurality of constituent members with screws or the like. A power cable 179 that can be connected to an external AC power source extends from the protruding end of the handle 17 . The handle 17 has a trigger 171 that is pushed (pulled) by the user, and a switch 172 that is turned on in response to the pushing operation of the trigger 171 .

In the hammer drill 101, when the switch 172 is turned on, the motor 2 is energized, the drive mechanism 5 is driven, and the hammer operation and/or the drill operation are performed.

A detailed configuration of the hammer drill 101 will be described below. In the following description, for the sake of convenience, the extending direction of the drive axis A1 (the longitudinal direction of the main body housing 10) is defined as the front-rear direction of the hammer drill 101. As shown in FIG. In the front-rear direction, the side on which the tool holder 32 is arranged is defined as the front side of the hammer drill 101, and the opposite side (the side where the motor 2 is arranged) is defined as the rear side. A vertical direction of the hammer drill 101 is defined as a direction perpendicular to the drive axis A1 and corresponding to the axial direction of the handle 17 . In the vertical direction, the side where the handle 17 is connected to the body housing 10 is defined as the upper side, and the projecting end side of the handle 17 is defined as the lower side. Moreover, the direction orthogonal to the front-back direction and the up-down direction is defined as the left-right direction of the hammer drill 101 . In the left-right direction, the right side of the hammer drill 101 is defined as the right side when the front side is viewed from the rear side, and the opposite side is defined as the left side of the hammer drill 101 .

First, the configuration of the body housing 10 will be described. As shown in FIG. 1, the body housing 10 has a cylindrical front end. This cylindrical portion is called a barrel portion 131 . A portion of the body housing 10 other than the barrel portion 131 is generally formed in a rectangular box shape. An auxiliary handle 132 is detachably attached to the barrel portion 131 .

The internal space of the body housing 10 is partitioned into two regions by a first support 15 arranged inside the body housing 10 . The first support 15 is arranged so as to intersect the drive axis A1, is fitted into the inner periphery of the main body housing 10, and is fixedly held by the main body housing 10 (immovably with respect to the main body housing 10). there is The area behind the first support 15 is primarily an area for housing the motor 2 . The area on the front side of the first support 15 is primarily the area for accommodating the spindle 31 and the drive mechanism 5 . Hereinafter, the portion of the body housing 10 corresponding to the accommodation area of the motor 2 will be referred to as the rear housing 11, and the portion corresponding to the accommodation area of the spindle 31 and the drive mechanism 5 (including the barrel portion 131) will be referred to as the front housing 13. .

Both the rear housing 11 and the front housing 13 are made of resin (plastic). Thereby, the weight of the hammer drill 101 can be reduced. However, at least part of the rear housing 11 and the front housing 13 may be made of any material (for example, metal). Each of rear housing 11 and front housing 13 is a single tubular member.

Although the details will be described later, the first support 15 is a member that supports bearings of various shafts. In order to ensure the positional accuracy of these bearings, the first support 15 is made of metal. In this embodiment, the first support 15 is made of an aluminum-based metal. Thereby, the weight of the hammer drill 101 can be reduced. As shown in FIG. 1 , the first support 15 is fitted to the rear end of the front housing 13 so that its outer peripheral surface contacts the inner peripheral surface of the front housing 13 .

As shown in FIG. 1 , an annular groove 152 is formed in the outer peripheral surface of the first support 15 that contacts the inner peripheral surface of the main body housing 10 . A rubber O-ring 151 is mounted in the groove 152 . The O-ring 151 functions as a sealing member that closes the gap between the main body housing 10 and the first support 15 and prevents the lubricant used in the front housing 13 from leaking into the rear housing 11. .

The internal structure of the body housing 10 will be described below. First, the motor 2 will be explained. In this embodiment, an AC motor driven by power supplied from an external AC power supply is employed as the motor 2 . As shown in FIG. 1, motor 2 is fixed to rear housing 11 . The motor 2 includes a main body 20 including a stator and a rotor, and a motor shaft 25 configured to rotate integrally with the rotor. In this embodiment, the rotation axis A2 of the motor shaft 25 extends parallel to the drive axis A1 below the drive axis A1.

The motor shaft 25 is rotatably supported around the rotation axis A2 with respect to the main body housing 10 via two bearings 251 and 252 . The front bearing 251 is held on the rear side of the first support 15 , and the rear bearing 252 is held on the rear housing 11 .

A cooling fan 27 for cooling the motor 2 is fixed to a portion of the motor shaft 25 between the main body 20 and the front bearing 251 . The cooling fan 27 is a centrifugal fan that draws air in the axial direction and discharges it radially outward. When the cooling fan 27 rotates as the motor shaft 25 rotates, an air flow is generated inside the hammer drill 101 . This airflow enters the inside of the hammer drill 101 from the outside of the hammer drill 101 through the air intake 28 , flows axially through the motor 2 (more specifically, between the rotor and the stator), and is cooled by the cooling fan 27 . It goes radially outward and is discharged to the outside from the exhaust port 29 . The path of air flow thus generated is indicated by arrow 26 in FIG.

1 shows an example in which the intake port 28 is formed on the side surface of the handle 17 and the exhaust port 29 is formed on the bottom surface of the rear housing 11, the intake port 28 and the exhaust port 29 may be formed at arbitrary locations. obtain. For example, the air intake 28 may be formed in the top surface of the handle 17 in addition to or instead of the sides of the handle 17 . In addition to or instead of the bottom surface of the rear housing 11 , the exhaust port 29 may be formed on one or both side surfaces or the top surface of the rear housing 11 . The motor 2 is cooled by the air flow thus generated.

The first support 15 is arranged adjacent to the cooling fan 27 in the front-rear direction, and the space behind the first support 15 communicates with the space in which the cooling fan 27 is arranged. Moreover, in this embodiment, the first support 15 is made of metal. Airflow through the passage 26 can thus also cool the first support 15 . In other words, it can be said that the first support 15 is arranged so as to be able to dissipate the heat generated on the front side of the first support 15 and transferred to the first support 15 . Details of this point will be described later.

The front end of the motor shaft 25 passes through the through hole 153 of the first support 15 and protrudes into the front housing 13 . A pinion gear 255 is fixed to the portion protruding into the front housing 13 .

Next, a power transmission path from the motor shaft 25 to the drive mechanism 5 will be described. As shown in FIGS. 2 and 3, in this embodiment, the hammer drill 101 has two intermediate shafts (first intermediate shaft 41 and second intermediate shaft 42). The driving mechanism 5 is configured to perform a hammering operation by power transmitted from the first intermediate shaft 41 and to perform a drilling operation by power transmitted from the second intermediate shaft 42 . That is, the first intermediate shaft 41 is a shaft dedicated to power transmission for hammering action. The second intermediate shaft 42 is dedicated to power transmission for drilling operations.

Both the first intermediate shaft 41 and the second intermediate shaft 42 extend parallel to the drive axis A1 and the rotation axis A2 within the front housing 13 . As shown in FIG. 3, the first intermediate shaft 41 is rotatably supported by two bearings 411 and 412 with respect to the body housing 10 around the rotation axis A3. Similarly, the second intermediate shaft 42 is rotatably supported by two bearings 421 and 422 with respect to the body housing 10 around the rotation axis A4.

A bearing 411 that supports the first intermediate shaft 41 on the front side and a bearing 421 that supports the second intermediate shaft 42 on the front side are supported by the second support 16 . More specifically, the bearing 411 is supported by a substantially cylindrical bearing support portion 164 of the second support 16 , and the bearing 421 is supported by a substantially cylindrical bearing support portion 165 . supported (see FIGS. 3, 13 and 14). A bearing 412 that supports the first intermediate shaft 41 on the rear side and a bearing 422 that supports the second intermediate shaft 42 on the rear side are supported by the first support 15 . More specifically, the bearing 412 is supported by a substantially cylindrical bearing support portion 154 of the first support 15, and the bearing 422 is supported by a substantially cylindrical bearing support portion 155. supported (see FIGS. 3 and 11).

As shown in FIG. 3, the bearing 411 that supports the first intermediate shaft 41 on the front side and the bearing 421 that supports the second intermediate shaft 42 on the front side are arranged at positions shifted from each other in the front-rear direction. . This is because the bearings 411 and 421 are arranged at positions for shortening each of the first intermediate shaft 41 and the second intermediate shaft 42 as much as possible. That is, although the bearings 411 and 421 are supported by a single member, that is, the second support 16 , the longitudinal positions of the bearings 411 and 421 are not restricted by the second support 16 . Therefore, the lengthening of the hammer drill 101 caused by supporting the bearings 411 and 421 with a single member is suppressed.

A second support 16 is fixed inside the front housing 13, as shown in FIGS. More specifically, as shown in FIGS. 13 and 14, the second support 16 has a first positioning portion 163, a mounting surface 168, and two through holes 162. As shown in FIG. The first positioning portion 163 is a cylindrical portion that protrudes forward. As shown in FIGS. 7 and 8, the first positioning portion 163 is arranged so as to surround the spindle 31 in the circumferential direction (in other words, the spindle 31 penetrates the first positioning portion 163 in the front-rear direction). be done. As shown in FIGS. 13 and 14 , the mounting surface 168 spreads on a single plane perpendicular to the front-rear direction on the radially outer side of the first positioning portion 163 . The two through holes 162 pass through the second support 16 in the front-rear direction.

On the other hand, the front housing 13 to which the second support 16 is fixed has a second positioning portion 133 and a mounting surface 135, as shown in FIGS. The second positioning portion 133 is a portion of the inner portion of the front housing 13 that protrudes rearward and has a concave portion formed radially inward, and surrounds the spindle 31 in the circumferential direction. A rear end surface of the second positioning portion 133 is formed as a mounting surface 135 perpendicular to the front-rear direction.

As shown in FIGS. 7 and 8, the second support 16 is attached to the front housing 13 such that the first positioning portion 163 is fitted in the recess of the second positioning portion 133 in the front-rear direction. By adopting such a fitting structure with uneven shapes, it is possible to easily and accurately position the second support 16 with respect to the front housing 13 in the direction perpendicular to the front-rear direction when assembling the hammer drill 101 . In alternative embodiments, the concave-convex relationship between the first positioning portion 163 and the second positioning portion 133 may be reversed. In other words, the first positioning portion 163 may be a recess formed in the second support 16, and the second positioning portion 133 may be a protrusion formed in the front housing 13, which is the second support. It may be a convex portion that fits into the 16 concave portions.

As shown in FIGS. 7 and 8 , when the first positioning portion 163 is fitted to the second positioning portion 133 in the front-rear direction, the mounting surface 168 of the second support 16 is aligned with the mounting surface 135 of the front housing 13 . and contact in the front-rear direction. Since the mounting surfaces 168 and 135 are both planes orthogonal to the front-rear direction, the second support 16 can be easily and accurately positioned in the front-rear direction with respect to the front housing 13 when the hammer drill 101 is assembled. .

The second support 16 positioned with respect to the front housing 13 in this manner is secured to the front housing 13 by screws 161 inserted into respective through holes 162 of the second support 16, as shown in FIG. fixed to

The second support 16 having such a structure is made of metal in order to ensure the positional accuracy of the bearings 411 and 421 . In this embodiment, the second support 16 is made of an aluminum-based metal. Thereby, the weight of the hammer drill 101 can be reduced.

As shown in FIG. 3 , a first driven gear 414 is fixed to the rear end of the first intermediate shaft 41 adjacent to the front side of the bearing 412 . The first driven gear 414 meshes with the pinion gear 255 .

A gear member 423 having a second driven gear 424 is arranged adjacent to the front side of the bearing 422 at the rear end of the second intermediate shaft 42 . The second driven gear 424 meshes with the pinion gear 255 . The gear member 423 is formed in a cylindrical shape and arranged on the outer peripheral side of the second intermediate shaft 42 (more specifically, the driving side member 74 described later). A spline portion 425 is provided on the outer circumference of the cylindrical front end portion of the gear member 423 . The spline portion 425 has a plurality of splines (external teeth) extending in the direction of the rotation axis A4 (front-rear direction). The rotation of the second driven gear 424 (gear member 423 ) is transmitted to the second intermediate shaft 42 via the second transmission member 72 and the torque limiter 73 , details of which will be described later.

Thus, in this embodiment, two power transmission paths branching from the motor shaft 25 are provided, and each of these paths is used as a power transmission path dedicated to hammer operation and a power transmission path dedicated to drill operation. be done.

The spindle 31 will be explained. Spindle 31 is the final output shaft of hammer drill 101 . As shown in FIG. 1, the spindle 31 is arranged along the drive axis A1 within the front housing 13 and is rotatably supported with respect to the main body housing 10 about the drive axis A1. The spindle 31 is configured as an elongated stepped cylindrical member.

The front half of the spindle 31 constitutes a tool holder 32 to which the tip tool 91 can be attached and detached. The tip tool 91 is inserted into the bit insertion hole 330 at the front end of the tool holder 32 so that its long axis coincides with the drive axis A1, is allowed to move in the axial direction with respect to the tool holder 32, and cannot rotate about the axis. Remain regulated. The latter half of the spindle 31 constitutes a cylinder 33 that slidably holds a piston 65, which will be described later. The spindle 31 is supported by a bearing 316 held within the barrel portion 131 and a bearing 317 held by a movable support 18, which will be described later.

The drive mechanism 5 will be described below. As shown in FIGS. 3, 5 and 6, in this embodiment, the drive mechanism 5 includes a striking mechanism 6 and a rotation transmission mechanism 7. As shown in FIGS. The impact mechanism 6 is a mechanism for performing a hammering action, and is configured to convert rotary motion of the first intermediate shaft 41 into linear motion and linearly drive the tip tool 91 along the drive axis A1. It is The rotation transmission mechanism 7 is a mechanism for performing a drilling operation, and is configured to transmit the rotational motion of the second intermediate shaft 42 to the spindle 31 and to rotationally drive the tip tool 91 around the drive axis A1. there is Detailed configurations of the impact mechanism 6 and the rotation transmission mechanism 7 will be described in order below.

In this embodiment, as shown in FIGS. 3 and 5, the striking mechanism 6 includes a motion conversion member 61, a piston 65, a striker 67, and an impact bolt 68.

The motion conversion member 61 is arranged around the first intermediate shaft 41 and configured to convert the rotational motion of the first intermediate shaft 41 into linear motion and transmit the linear motion to the piston 65 . More specifically, the motion conversion member 61 includes a rotor 611 and a swing member 616 . The rotating body 611 is supported by a bearing 614 so as to be rotatable about the rotation axis A3 with respect to the main body housing 10 . The swinging member 616 is rotatably attached to the outer periphery of the rotating body 611, and is configured to swing in the extending direction (back and forth direction) of the rotation axis A3 as the rotating body 611 rotates. The rocking member 616 has an arm portion 617 extending upward from the rotating body 611 .

The piston 65 is a cylindrical member with a bottom, and is slidably arranged in the cylinder 33 of the spindle 31 along the drive axis A1. The piston 65 is connected to the arm portion 617 of the swinging member 616 via a connecting pin, and reciprocates in the front-rear direction as the swinging member 616 swings.

The striker 67 is a striker for applying a striking force to the tip tool 91 . A striker 67 is slidably disposed within the piston 65 along the drive axis A1. The internal space of the piston 65 on the rear side of the striker 67 is defined as an air chamber that functions as an air spring. The impact bolt 68 is a meson that transmits the kinetic energy of the striker 67 to the tip tool 91 . The impact bolt 68 is arranged in the tool holder 32 on the front side of the striker 67 so as to be movable along the drive axis A1.

When the piston 65 is moved back and forth along with the rocking of the rocking member 616, the pressure of the air in the air chamber fluctuates, and the striker 67 slides back and forth inside the piston 65 due to the action of the air spring. . More specifically, when the piston 65 moves forward, the air in the air chamber is compressed to increase the internal pressure. The striker 67 is pushed forward at high speed by the action of the air spring and strikes the impact bolt 68 . The impact bolt 68 transmits the kinetic energy of the striker 67 to the tip tool 91 . As a result, the tip tool 91 is linearly driven along the driving axis A1. On the other hand, when the piston 65 is moved rearward, the air in the air chamber expands, the internal pressure drops, and the striker 67 is pulled rearward. The tip tool 91 moves backward together with the impact bolt 68 by being pressed against the workpiece. In this manner, the hammering action is repeated by the striking mechanism 6 .

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

As shown in FIG. 5, the intervening member 63 is arranged coaxially with the first intermediate shaft 41 around the first intermediate shaft 41 so that the first intermediate shaft 41 and the motion converting member 61 (specifically, the rotating body) are connected to each other. 611). The intervening member 63 is immovable in the front-rear direction with respect to the first intermediate shaft 41 , but is rotatable with respect to the first intermediate shaft 41 around the rotation axis A3.

More specifically, the front end portion of the first intermediate shaft 41 (the portion adjacent to the rear side of the front bearing 411) is configured as a maximum diameter portion having the maximum outer diameter. A spline portion 416 is provided on the outer circumference of the maximum diameter portion. The spline portion 416 has a plurality of splines (external teeth) extending in the direction of the rotation axis A3 (front-rear direction). The intervening member 63 is held between the spline portion 416 and the first driven gear 414 fixed to the rear end portion of the first intermediate shaft 41 so as not to move in the front-rear direction.

A spline portion 631 is provided on the outer periphery of the intervening member 63 so as to extend substantially over the entire length of the intervening member 63 . The spline portion 631 has a plurality of splines (external teeth) extending in the direction of the rotation axis A3 (front-rear direction).

On the other hand, a spline portion 612 is formed on the inner circumference of the rotor 611 . The spline portion 612 has splines (internal teeth) that engage with the spline portion 631 . The intervening member 63 is always spline-engaged with the rotating body 611 and held by the rotating body 611 . With such a configuration, the rotating body 611 can move in the direction of the rotation axis A3 (front-rear direction) with respect to the intervening member 63 and the first intermediate shaft 41, and can rotate integrally with the intervening member 63. .

The first transmission member 64 is arranged on the first intermediate shaft 41, is rotatable integrally with the first intermediate shaft 41, and rotates relative to the first intermediate shaft 41 and the intervening member 63 in the direction of the rotation axis A3 (front-to-rear direction). ).

More specifically, the first transmission member 64 is a substantially cylindrical member arranged around the first intermediate shaft 41, and has a first spline portion 641 and a A second spline portion 642 is provided.

The first spline portion 641 is provided at the rear end portion of the first transmission member 64 . The first spline portion 641 has a plurality of splines (internal teeth) that can be engaged with the spline portion 631 of the interposed member 63 . As described above, the spline portion 631 of the intervening member 63 is also engaged with the spline portion 612 of the rotor 611 . The second spline portion 642 is provided in the front half portion of the first transmission member 64 . The second spline portion 642 has a plurality of splines (internal teeth) that always engage the spline portion 416 of the first intermediate shaft 41 .

With such a configuration, as shown in FIG. 5, the first spline portion 641 of the first transmission member 64 movable in the front-rear direction engages with the spline portion 631 of the intervening member 63 in the front-rear direction (hereinafter referred to as "position"). , the engaged position), the first transmission member 64 can rotate integrally with the intervening member 63 , that is, can transmit power from the first intermediate shaft 41 to the intervening member 63 .

On the other hand, the first spline portion 641 of the first transmission member 64 movable in the front-rear direction is positioned at a position (hereinafter referred to as the separated position) where the first spline portion 641 is separated from the spline portion 631 (disengageable) in the front-rear direction. ) (not shown), the first transmission member 64 disables (blocks) power transmission from the first intermediate shaft 41 to the intervening member 63 .

As shown in FIG. 6 , the rotation transmission mechanism 7 includes a drive gear 78 and a driven gear 79 in this embodiment. The drive gear 78 is fixed to the front end portion of the second intermediate shaft 42 (the portion adjacent to the rear side of the front bearing 421). The driven gear 79 is fixed to the outer circumference of the cylinder 33 of the spindle 31 and meshes with the drive gear 78 . The driving gear 78 and the driven gear 79 constitute a gear reduction mechanism. As the driving gear 78 rotates integrally with the second intermediate shaft 42 , the spindle 31 rotates integrally with the driven gear 79 . As a result, a drill operation is performed in which the tip tool 91 held by the tool holder 32 is rotationally driven around the driving axis A1.

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

As shown in FIG. 6 , the torque limiter 73 includes a driving side member 74 , a driven side member 75 and a biasing spring 77 . The drive-side member 74 is a cylindrical member, and is rotatably supported with respect to the second intermediate shaft 42 by the rear half portion of the second intermediate shaft 42 . The driven side member 75 is a cylindrical member and is arranged around the second intermediate shaft 42 on the front side of the drive side member 74 . The driven side member 75 is configured to be rotatable integrally with the second intermediate shaft 42 and to be movable relative to the second intermediate shaft 42 in the direction of the rotation axis A4 (front-rear direction). The biasing spring 77 always biases the driven side member 75 in the direction of approaching the driving side member 74 . Therefore, normally, the front end portion of the drive-side member 74 and the rear end portion of the driven-side member 75 are engaged to transmit torque from the drive-side member 74 to the driven-side member 75, and eventually the second intermediate shaft 42. Rotation is possible.

When a load equal to or greater than a threshold value is applied to the second intermediate shaft 42 via the tool holder 32 (spindle 31 ) while the second intermediate shaft 42 is rotating, the driven side member 75 is pushed against the biasing force of the biasing spring 77 . moves in a direction (forward) away from the driving side member 74, and the engagement between the driven side member 75 and the driving side member 74 is released. As a result, torque transmission from the driving side member 74 to the driven side member 75 is cut off, and the rotation of the second intermediate shaft 42 is interrupted.

The driving side member 74 includes a spline portion 743 . The spline portion 743 is provided on the outer periphery of the drive-side member 74 and has a plurality of splines (external teeth) extending in the direction of the rotation axis A4 (front-rear direction).

As shown in FIG. 6 , the second transmission member 72 is arranged around the second intermediate shaft 42 , is rotatable integrally with the drive side member 74 of the torque limiter 73 , and is connected to the drive side member 74 and the gear member 423 . It is configured to be movable in the direction of the rotation axis A4 (forward and backward direction).

More specifically, the second transmission member 72 is a substantially cylindrical member arranged around the drive-side member 74. The inner periphery of the second transmission member 72 includes a first spline portion 721 and a second A two-spline portion 722 is provided. The first spline portion 721 is provided in the front half portion of the second transmission member 72 . The first spline portion 721 has a plurality of splines (internal teeth) that are always engaged with the spline portion 743 of the driving side member 74 . The second spline portion 722 is provided at the rear end portion of the second transmission member 72 and has an inner diameter larger than that of the first spline portion 721 . The second spline portion 722 has a plurality of splines (internal teeth) that can be engaged with the spline portion 425 of the gear member 423 .

With such a configuration, as shown in FIG. 6, the second spline portion 722 of the second transmission member 72 movable in the front-rear direction engages with the spline portion 425 of the gear member 423 in the front-rear direction (hereinafter referred to as a position). , the engaged position), the second transmission member 72 is rotatable integrally with the gear member 423 . Therefore, the drive-side member 74 spline-engaged with the second transmission member 72 and the second intermediate shaft 42 to which torque is transmitted via the driven-side member 75 are also rotatable integrally with the gear member 423. .

On the other hand, when the second spline portion 722 that is movable in the front-rear direction is arranged at a position (hereinafter referred to as a separated position) that is separated (disengageable) from the spline portion 425 in the front-rear direction (not shown). , the second transmission member 72 disables (cuts off) the power transmission from the gear member 423 to the driving side member 74 and further to the second intermediate shaft 42 .

As described above, in the present embodiment, the first transmission member 64 and the intervening member 63 function as a first clutch mechanism that transmits or cuts off power for hammering, and the second transmission member 72 and the gear member 423 functions as a second clutch mechanism that transmits or blocks power for drilling operations. Each of the first clutch mechanism and the second clutch mechanism is switched between the power transmission state and the cutoff state according to the operation of the mode switching dial 800 (see FIG. 1) by the user. More specifically, an intermediate member (not shown) configured to interlock with mode-switching dial 800 rotates first transmission member 64 and/or second transmission member 72 depending on the dial position of mode-switching dial 800. The position is changed, thereby realizing the switching of the first clutch mechanism and the second clutch mechanism.

In this embodiment, the hammer drill 101 has three operation modes switched by operating the mode switching dial 800, ie, hammer drill mode, hammer mode, and drill mode. The hammer drill mode is an operation mode in which both the impact mechanism 6 and the rotation transmission mechanism 7 are driven to perform a hammer operation and a drill operation. The hammer mode is an operation mode in which power transmission for drill operation is cut off by the second clutch mechanism and only the impact mechanism 6 is driven, so that only hammer operation is performed. The drill mode is an operation mode in which power transmission for hammer operation is cut off by the first clutch mechanism and only the rotation transmission mechanism 7 is driven so that only drill operation is performed.

As described above, the hammer drill 101 of the present embodiment extends parallel to the drive axis A1 and has two separate intermediate shafts (first intermediate shafts) for power transmission for hammering and drilling respectively. 41 and a second intermediate shaft 42). Therefore, the length of the first intermediate shaft 41 and the second intermediate shaft 42 can be shortened compared to the case where one common intermediate shaft is employed for power transmission for hammering and drilling operations. This makes it possible to shorten the length of the entire hammer drill 101 in the axial direction.

Further, the first intermediate shaft 41 and the second intermediate shaft 42 are specialized for power transmission for hammering operation and power transmission for drilling operation, respectively. Therefore, the power transmission via the first intermediate shaft 41 and the power transmission via the second intermediate shaft 42 can be optimized respectively.

By the way, in this embodiment, the hammer drill 101 is configured so as to suppress transmission of vibration (in particular, vibration in the front-rear direction) caused by driving the drive mechanism 5 to the main body housing 10 and the handle 17 . . The anti-vibration structure of the hammer drill 101 will be described below.

In this embodiment, as shown in FIG. 1, the spindle 31 and the striking mechanism 6 (more specifically, the motion conversion member 61, the piston 65, the striker 67, and the impact bolt 68) are attached to the body housing 10 inside the body housing 10. It is arranged so as to be movable in the axial direction (front-to-rear direction). More specifically, inside the body housing 10, a movable support 18 is arranged which can move forward and backward with respect to the body housing 10 while being biased forward. The spindle 31 and the striking mechanism 6 are supported by the movable support 18 and are movable integrally with the movable support 18 with respect to the body housing 10 .

As shown in FIGS. 5, 6 and 12, the movable support 18 includes a spindle support 185 and a rotor support 187. As shown in FIGS. In this embodiment, the movable support 18 is constructed as a single piece of metal.

The spindle support portion 185 is formed in a substantially cylindrical shape and configured as a portion that supports the spindle 31 . As shown in FIGS. 5 and 6, a bearing 317 is held inside the spindle support 185 . The spindle support portion 185 supports the rear portion of the cylinder 33 via a bearing 317 so as to be rotatable around the drive axis A1. As described above, the spindle 31 is supported by the bearings 316 and 317 so as to be rotatable about the drive axis A1 with respect to the main body housing 10 . The other bearing 316 is held within the barrel portion 131 and supports the rear portion of the tool holder 32 so as to be rotatable about the drive axis A1 and movable in the longitudinal direction.

The rotating body support portion 187 is a portion formed in a substantially cylindrical shape and is positioned on the lower right side of the spindle support portion 185 . As shown in FIG. 5, a bearing 614 is fixed to the rotor support portion 187 with screws. The rotating body support portion 187 supports the rotating body 611 via a bearing 614 so as to be rotatable around the rotation axis A3.

As described above, the spindle 31 and the rotating body 611 are supported by the movable support 18, so that the swinging member 616 attached to the rotating body 611, the piston 65, the striker 67, and impact bolt 68 are also supported on the movable support 18 . Therefore, the movable support 18, the spindle 31, and the striking mechanism 6 constitute a movable unit 180 as an assembly that can move integrally in the front-rear direction with respect to the body housing 10 (in other words, the motor 2). do.

The forward and backward movement of the movable unit 180 including the movable support 18 is slidably guided by a pair of first guide shafts 191 and a pair of second guide shafts 192 . As shown in FIGS. 7 and 8, the pair of first guide shafts 191 and the pair of second guide shafts 192 coaxially extend in the axial direction (front-rear direction).

More specifically, as shown in FIGS. 7, 8 and 12, the movable support 18 has a pair of cylindrical portions 181 radially outward of the spindle support portion 185 (in FIG. 12, one cylindrical portion only part 181 is visible). As shown in FIGS. 7 and 8, the pair of cylindrical portions 181 are arranged symmetrically. In other words, the pair of cylindrical portions 181 are arranged symmetrically with respect to a virtual plane P1 (see FIG. 2) including the drive axis A1 and the rotation axis A2. A hole 183 penetrating through the cylindrical portion 181 in the front-rear direction is formed in each of the cylindrical portions 181 . Substantially the rear half of the first guide shaft 191 is press-fitted into each of the holes 183 , and substantially the front half of the first guide shaft 191 extends forward from the movable support 18 . Thereby, the first guide shaft 191 is fixed to the movable support 18 and configured to move integrally with the movable support 18 in the front-rear direction.

The pair of first guide shafts 191 are received within a pair of holes 166 (see FIGS. 13 and 14) of the second support 16 . More specifically, as shown in FIGS. 7 and 8, the hole 166 extends through the second support 16 in the front-rear direction. The inner diameter of the front side of the hole 166 is larger than the inner diameter of the rear side, so that a step is formed on the inner surface of the second support 16 forming the hole 166 . The second support 16 has a cylindrical sleeve 167 within the bore 166 . The sleeve 167 is press-fitted into the large-diameter portion on the front side of the hole 166 so that the rear end of the sleeve 167 abuts the step on the inner surface of the hole 166 . The first guide shaft 191 is always received within the sleeve 167 so as to slide on the inner peripheral surface of the sleeve 167 as the movable support 18 moves in the front-rear direction. The first guide shaft 191 is in sliding relationship only with respect to the sleeve 167 of the second support 16 . In this embodiment, the front end of sleeve 167 abuts front housing 13 . Therefore, even if the first guide shaft 191 slides on the inner peripheral surface of the sleeve 167 , the sleeve 167 does not slip out of the hole 166 . In this embodiment, the sleeve 167 is made of ferrous metal. As described above, the portions of the second support 16 other than the sleeve 167 are made of an aluminum-based metal. It is possible to achieve both sufficient strength against movement and weight reduction of the second support 16 as a whole.

The pair of second guide shafts 192 are located on the rear side of the pair of first guide shafts 191 and are held by the first support 15 . More specifically, as shown in FIGS. 7, 8 and 11, the first support 15 includes a pair of shaft supports 156 cylindrically extending forward from a plate-like base 150 perpendicular to the front-rear direction. It has Approximately the rear halves of the pair of second guide shafts 192 are press-fitted into the shaft support portion 156 . Therefore, the pair of second guide shafts 192 are immovable with respect to the first support 15 and thus the main body housing 10 . Approximately half of the front side of the pair of second guide shafts 192 extends forward from the first support 15 .

As shown in FIGS. 7, 8 and 12, the movable support 18 has a pair of cylindrical portions 182 coaxially with the pair of cylindrical portions 181 . Each cylindrical portion 182 is formed with a hole 184 penetrating through the cylindrical portion 182 in the front-rear direction. The inner diameter of the rear side of the hole 184 is larger than the inner diameter of the front side, and as a result, a step is formed on the inner surface of the cylindrical portion 182 forming the hole 184 . Movable support 18 includes a cylindrical sleeve 186 within bore 184 . The sleeve 186 is press-fitted into the large-diameter portion of the rear side of the hole 184 so that the front end of the sleeve 186 contacts the step on the inner surface of the hole 184 . The front end portions of the pair of second guide shafts 192 are always received within the sleeves 186 so that the inner peripheral surface of the sleeves 186 slides on the second guide shafts 192 as the movable support 18 moves back and forth. It is The second guide shaft 192 is in sliding relationship only with the sleeve 186 of the movable support 18 . In this embodiment, the sleeve 186 is made of ferrous metal. As described above, the portions of the second support 16 other than the sleeve 186 are made of an aluminum-based metal. It is possible to achieve both sufficient strength against the movement and weight reduction of the movable support 18 as a whole. In this embodiment, the first guide shaft 191 and the second guide shaft 192 are made of ferrous metal.

By guiding the fore-and-aft movement of the movable support 18 by means of a first guide shaft 191 and a second guide shaft 192 spaced in the fore-and-aft direction, a single guide shaft can move from the position of the first guide shaft 191 to the second guide shaft. Compared to the case where it extends to the position of the shaft 192, the extension distance of the entire guide shaft can be shortened. Therefore, the weight of the hammer drill 101 can be reduced. Moreover, since the guide shafts are positioned on both sides in the front-rear direction with respect to the movable support 18, the guide performance does not deteriorate as the weight is reduced.

A pair of urging springs 193 are arranged behind the movable support 18 . A pair of biasing springs 193 are compression coil springs and are arranged in a compressed state between the first support 15 and the movable support 18 . More specifically, the pair of urging springs 193 are arranged around the pair of second guide shafts 192, respectively. A rear end of the biasing spring 193 abuts a washer disposed between the biasing spring 193 and the base 150 of the first support 15 . The biasing spring 193 is fitted around the shaft support portion 156, thereby restricting movement of the biasing spring 193 on a plane perpendicular to the front-rear direction. A front end of the biasing spring 193 abuts a washer 195 disposed between the biasing spring 193 and the movable support 18 .

The sleeve 186 arranged in the hole 184 of the cylindrical portion 182 is always urged forward by the urging spring 193 via the washer 195, so that the movable support 18 moves forward. In this case, it can always move integrally with the movable support 18 . That is, when the movable support 18 moves forward, the sleeve 186 will not be left behind and come out of the hole 184 .

With such a configuration, the pair of biasing springs 193 always biases the movable support 18 (movable unit 180) forward. Therefore, when no rearward external force acts on the movable support 18, the movable support 18 is at the most forward position ( initial position). An elastic member may be attached to the rear surface of the second support 16 to avoid direct contact between the second support 16 and the movable support 18 (to buffer the impact force). good.

On the other hand, when a rearward external force acts on the movable support 18, the movable support 18 can move to the rearmost position shown in FIG. The structure that defines this rearmost position will be described below.

As shown in FIGS. 9 to 11, the first support 15 includes a pair of elastic member holding portions 158 extending forward from the base 150 in a bottomed cylindrical shape. The pair of elastic member holding portions 158 are arranged symmetrically. A hole 159 is formed in the elastic member holding portion 158 . As shown in FIG. 11 , the elastic member holding portion 158 extends further forward than the shaft support portion 156 . A cylindrical elastic member 194 is arranged in each hole 159 of the elastic member holding portion 158 . The rear end of the elastic member 194 is in contact with the base 150 , and the front end of the elastic member 194 protrudes further forward than the front end of the elastic member holding portion 158 . The elastic member 194 is held in a fitted state within the elastic member holding portion 158 . More specifically, the outer diameter of the elastic member 194 is slightly larger than the inner diameter of the elastic member holding portion 158 . Therefore, the elastic member 194 is slightly crushed radially inward within the elastic member holding portion 158 and is held within the hole 159 by its restoring force. With such a configuration, the elastic member 194 can be easily attached and detached. Therefore, manufacturing is facilitated, and replacement work when the elastic member 194 is deteriorated or worn is facilitated.

As shown in FIGS. 9, 10 and 12, the movable support 18 has a pair of protrusions 188 and a contact portion 189. As shown in FIG. The protrusion 188 extends rearward from the cylindrical portion 182 in a columnar shape. This projection 188 is always received within a corresponding elastic member 194 . The outer diameter of projection 188 is slightly larger than the inner diameter of elastic member 194 . Therefore, the elastic member 194 is slightly crushed radially outward, and the restoring force of the elastic member 194 keeps the protrusion 188 and the elastic member 194 in a fitted state at all times. When the movable support 18 moves in the front-rear direction, the projection 188 slides on the inner surface of the elastic member 194 while maintaining the fitted state with the elastic member 194 . The contact portion 189 connects the base portions of the pair of protrusions 188 in an arch shape, and is formed as a plane perpendicular to the front-rear direction.

When the movable support 18 is at the forwardmost position shown in FIG. 7, the contact portion 189 of the movable support 18 is separated from the front end portion of the elastic member 194 in the front-rear direction, as shown in FIG. On the other hand, when the movable support 18 is at the rearmost position shown in FIG. 8, the contact portion 189 of the movable support 18 contacts the front end portion of the elastic member 194 in the front-rear direction, as shown in FIG. there is That is, the elastic member 194 functions as a stopper that restricts further rearward movement of the movable support 18 . This structure defines the rearmost position shown in FIG. 8 of the movable support 18 .

In the hammer drill 101 described above, in the hammer drill mode and the hammer mode in which the hammer operation is performed, the tip tool 91 is pressed against the workpiece, and when the machining operation is performed, the impact mechanism 6 drives the tip tool 91, and Due to the reaction force of the impact force of the tip tool 91 from the workpiece, the impact mechanism 6 mainly vibrates in the front-rear direction. This vibration causes the movable unit 180 to move in the front-rear direction with respect to the body housing 10 while being slidably guided by the first guide shaft 191 and the second guide shaft 192 . At this time, the biasing spring 193 expands and contracts (elastically deforms), thereby absorbing the vibration of the movable unit 180 and reducing the vibration transmitted to the body housing 10 and the handle 17 . When the movable unit 180 moves to the rearmost position, the contact portion 189 of the movable support 18 collides with the elastic member 194, and the elastic member 194 is elastically deformed. is absorbed.

According to the hammer drill 101 described above, the bearings 411 and 421 supporting the front end portions of the first intermediate shaft 41 and the second intermediate shaft 42 respectively are supported by the metal second support 16 . Therefore, greater support strength can be obtained than when the bearings 411 and 421 are supported by a resin support. Therefore, even if the vibration caused by the reaction force to the impact force increases as the hammer drill 101 becomes more powerful, the bearings 411 and 421, and the first intermediate shaft 41 and the second intermediate shaft 42 are required position accuracy can be ensured. A similar effect can be obtained from the fact that the bearings 412 and 422 that support the rear ends of the first intermediate shaft 41 and the second intermediate shaft 42, respectively, are supported by the metal first support 15. As shown in FIG.

Furthermore, according to the hammer drill 101, the first guide shaft 191 is partially received in the hole 166 of the second metal support 16 (more specifically, in the hole of the sleeve 167). Therefore, even if the amount of heat generated when the first guide shaft 191 slidably guides the movement of the movable support 18 in the front-rear direction increases as the power of the hammer drill 101 increases, the first guide shaft Thermal expansion of the second support 16 is suppressed as compared with the case where 191 is received in a resin support. Therefore, the positional accuracy of the first guide shaft 191 partially received in the hole 166 of the second support 16 can be ensured. As a result, good slidability regarding the first guide shaft 191 can be ensured, and good anti-vibration properties can be obtained. A similar effect results from the fact that the second guide shaft 192 is partially received within the hole 184 of the metal movable support 18 (more specifically, within the hole of the sleeve 186).

Thus, the hammer drill 101 can achieve both high power and low vibration. Moreover, since the support of the bearings 411 and 421 and the reception of the first guide shaft 191 are realized by the second support 16, which is a single member, the device configuration can be simplified and the number of manufacturing steps can be reduced. can.

Furthermore, the hammer drill 101 can utilize the elastic member 194 functioning as a stopper to improve the heat dissipation property for the heat generated due to the sliding movement of the movable support 18 in the front-rear direction. The configuration will be described below. As described above with reference to FIGS. 9 and 10, the elastic member 194 is arranged between the movable support 18 (more specifically, the protrusion 188) and the first support regardless of the longitudinal position of the movable support 18. 15 (more specifically, elastic member holding portion 158).

The elastic member 194 uses an elastic material having thermal conductivity (for example, heat transfer rubber). Thermal conductivity may be imparted by including fillers such as metals, carbon nanotubes, etc. in the elastic material forming elastic member 194 . “Having thermal conductivity” can be defined as having a thermal conductivity of 1.0 (W/m·K) or more, for example.

As described above, the first support 15 is made of metal and is positioned adjacent to the airflow passage 26 generated by the rotation of the cooling fan 27 . Therefore, the heat generated by the sliding movement of the movable support 18 in the front-rear direction is transferred from the movable support 18 to the first support 15 via the thermally conductive elastic member 194, thereby cooling the first support 15. Heat can be efficiently dissipated by the air flow generated by the rotation of the fan 27 .

In this embodiment, the elastic member 194 and the protrusion 188 of the movable support 18 are always maintained in a fitted state. For this reason, the contact area between the elastic member 194 and the movable support 18 is increased compared to a configuration in which they are in planar contact. Therefore, the ability to transfer heat from the movable support 18 to the elastic member 194 is enhanced, and heat dissipation can be further improved. In addition, the elastic member 194 and the elastic member holding portion 158 of the first support 15 are always maintained in a fitted state. Therefore, the contact area between the elastic member 194 and the first support member 15 is increased compared to a configuration in which they are in planar contact. Therefore, the ability to transfer heat from the elastic member 194 to the first support 15 is enhanced, and the heat dissipation can be further improved. Moreover, these fitting states are realized in such a manner that the cylindrical shape and the columnar or cylindrical shape are fitted. For this reason, it is possible to secure a large contact area and also obtain ease of manufacture.

Furthermore, as shown in FIG. 11, the elastic member 194 is positioned adjacent to the second guide shaft 192 . Therefore, it is possible to shorten the heat transfer distance from the location where heat is generated due to the sliding to the elastic member 194 via the movable support 18 . Therefore, more efficient heat dissipation is possible.

Furthermore, as shown in FIG. 11, on a virtual plane perpendicular to the drive axis A1 (in other words, a plane on which the base 150 spreads), one of the pair of second guide shafts 192 (right side) and one of the second guide shafts 192 The distance between one (right side) of the pair of elastic members 194 arranged adjacent to the shaft 192 is the other (left side) of the pair of second guide shafts 192 and the other (left side) of the pair of elastic members 194. is equal to the distance between and . Therefore, the distance of the heat transfer path from one second guide shaft 192 to one elastic member 194 and the distance of the heat transfer path from the other second guide shaft 192 to the other elastic member 194 are equal. (Such an arrangement is also called an equidistant arrangement). Therefore, the occurrence of temperature unevenness in the movable support 18 is suppressed, and uniform heat dissipation becomes possible.

Although the example of FIG. 11 shows an equidistant arrangement in which one elastic member 194 is associated with one second guide shaft 192, in alternative embodiments A plurality of elastic members 194 may be associated with each other. For example, when two elastic members 194 are associated with one second guide shaft 192 (in this case, the total number of elastic members 194 is four), one second guide shaft 192 and Equidistant arrangement is realized so that the distance between each of the two corresponding elastic members 194 is equal to the distance between each of the other second guide shaft 192 and the two corresponding elastic members 194. may be

Correspondence between each component of the above embodiment and each component of the present invention is shown below. However, each component of the embodiment is merely an example, and does not limit each component of the present invention. Hammer drill 101 is an example of a "percussion tool." Spindle 31 is an example of a "final output shaft." The drive axis A1 is an example of a "drive axis". Motor 2 and motor shaft 25 are examples of "motor" and "motor shaft", respectively. The drive mechanism 5 is an example of a "drive mechanism." Movable support 18 is an example of a "movable support." The biasing spring 193 is an example of a "biasing member." The second guide shaft 192 (or the second guide shaft 192 and the first guide shaft 191) is an example of "at least one guide shaft." The first support 15 is an example of a “metal member”. The elastic member 194 is an example of "at least one elastic member." Cooling fan 27 is an example of a "fan".

The above-described embodiment is merely an example, and the impact tool according to the present invention is not limited to the configuration of the hammer drill 101 illustrated. For example, the modifications exemplified below can be made. Any one of these modifications, or a plurality thereof, may be employed in combination with the hammer drill 101 shown in the embodiment or the invention described in each claim.

Instead of the first intermediate shaft 41 and the second intermediate shaft 42, a single intermediate shaft may be used for both power transmission for hammer operation and power transmission for drill operation. Such configurations are described, for example, in US Patent Application Publication No. 2017/106517. The disclosure of US Patent Application Publication No. 2017/106517 is hereby incorporated by reference in its entirety.

The first guide shaft 191 may be fixedly received within the hole 166 of the second support 16 instead of being fixedly held by the movable support 18 . In this case, the first guide shaft 191 held by the second support 16 may be slidably received within a hole formed in the movable support 18 .

The constant contact between the movable support 18, the elastic member 194 and the first support 15 can be changed in any manner. For example, the elastic member holding portion 158 may be formed in a cylindrical shape, the elastic member 194 may be formed in a cylindrical shape surrounding the elastic member holding portion 158 , and the projection 188 may be formed in a cylindrical shape surrounding the elastic member 194 . Alternatively, the movable support 18, the elastic member 194, and the first support 15 may be in planar contact.

An elastic member having thermal conductivity (the elastic member 194 in the above-described embodiment) may be arranged so as to be in constant contact with the movable support 18 and any metal member arranged to allow heat dissipation. good. In this case, the metal member may extend from the front side of the first support 15 through the first support 15 and onto the airflow passage 26 . Alternatively, the metal member may be any member arranged to be at least partially exposed to the outside of hammer drill 101 . For example, at least a part of the portion of the body housing 10 exposed to the outside may be made of metal, and the metal portion and the elastic member may always be in contact with each other.

In the above-described embodiment, the hammer drill 101 capable of performing a hammering action and a drilling action is exemplified as an example of the impact tool. However, the impact tool may also be an electric hammer capable of performing only hammering action.

2 Motor 5 Drive Mechanism 6 Impact Mechanism 7 Rotation Transmission Mechanism 10 Body Housing 11 Rear Housing 13 Front Housing 15 First Support Body 16...Second support 17...Handle 18...Movable support 20...Body part 25...Motor shaft 26...Air flow passage 27...Cooling fan 28.. Intake port 29... Exhaust port 31... Spindle 32... Tool holder 33... Cylinder 41... First intermediate shaft 42... Second intermediate shaft 61... Motion conversion member 63. ..Interposition member 64...First transmission member 65...Piston 67...Striker 68...Impact bolt 72...Second transmission member 73...Torque limiter 74...Drive side member 75 ... Driven side member 77... Biasing spring 78... Drive gear 79... Driven gear 91... Tip tool 101... Hammer drill 131... Barrel part 132... Auxiliary handle 133. ..Second positioning part 135...Mounting surface 150...Base 151...O-ring 152...Groove 153...Through hole 154, 155...Bearing support part 156...Shaft support part 158... Elastic member holding part 159... Hole 161... Screw 162... Through hole 163... First positioning part 164, 165... Bearing support part 166... Hole 167... Sleeve 168 Mounting surface 171 Trigger 172 Switch 179 Power cable 180 Movable unit 181, 182 Cylindrical portion 183, 184 Hole 185 Spindle support Part 186... Sleeve 187... Rotating body support part 188... Protrusion 189... Contact part 191... First guide shaft 192... Second guide shaft 193... Biasing spring 194 ... elastic member 195... washer 251, 252... bearing 255... pinion gear 316, 317... bearing 330... bit insertion hole 411, 412... bearing 414... first driven Gear 416... Spline part 421, 422... Bearing 423... Gear member 424... Second driven gear 425... Spline part 611... Rotating body 612... Spline part 614... Bearing 61 6... Rocking member 617... Arm part 631... Spline part 641... First spline part 642... Second spline part 721... First spline part 722... Second spline Part 743... Spline part 800... Mode switching dial A1... Drive axis A2, A3, A4... Rotation axis P1... Virtual plane

Claims (10)

an impact tool,
a final output shaft configured to removably retain an accessory tool and defining a drive axis for the accessory tool;
a motor having a motor shaft;
a drive mechanism configured to linearly drive the tip tool along the drive axis by the power of the motor;
a movable support that at least partially supports the final output shaft and the drive mechanism, the movable support configured to be integrally movable with respect to the motor in the axial direction of the drive axis;
When the side on which the final output shaft is arranged in the axial direction is defined as the front side and the side on which the motor is arranged is defined as the rear side, the movable support is biased toward the front side in the axial direction. a biasing member;
at least one guide shaft extending in the axial direction and configured to slidingly guide the axial movement of the movable support;
a metal member disposed so as to be capable of dissipating heat;
at least one thermally conductive elastic member arranged to be in constant contact with the movable support and the metal member regardless of the axial position of the movable support; A percussion tool comprising a resilient member; The impact tool according to claim 1,
The impact tool, wherein the metal member is arranged to be at least partially exposed to the outside of the impact tool. The impact tool according to claim 1 or 2,
further comprising a fan fixed to the motor shaft;
The metal member is positioned on or adjacent to a passageway of air flow generated by rotation of the fan. The impact tool according to any one of claims 1 to 3,
the at least one elastic member is retained on the metallic member;
The impact tool, wherein the movable support slides on the at least one elastic member as the movable support moves in the axial direction. The impact tool according to any one of claims 1 to 4,
The impact tool, wherein the at least one elastic member and the movable support are always kept in a fitted state. An impact tool according to claim 5,
The at least one elastic member and the movable support are so fitted that the at least one elastic member and the movable support are fitted in a cylindrical shape, a columnar shape, or a cylindrical shape. A striking tool having a shaped movable support. The impact tool according to any one of claims 1 to 6,
The at least one elastic member is positioned adjacent to the at least one guide shaft. Impact tool. The impact tool according to any one of claims 1 to 7,
The at least one elastic member abuts against the movable support in the axial direction when the movable support moves rearward in the axial direction, and further moves the movable support rearward. An impact tool that functions as a stopper that restricts movement. The impact tool according to any one of claims 1 to 8,
the at least one guide shaft comprises a plurality of guide shafts;
the at least one elastic member comprises a plurality of elastic members corresponding to the plurality of guide shafts;
The at least one guide shaft and the at least one elastic member are arranged such that the distances between each of the plurality of guide shafts and the corresponding elastic member on an imaginary plane perpendicular to the drive axis are equal to each other. percussion tools. The impact tool according to any one of claims 1 to 9,
The metallic member has at least one hole,
The at least one elastic member is fitted and retained within the at least one hole.

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