Impact tools

Abstract

To provide an improvement in the vibration control structure of an impact tool.SOLUTION: An impact tool includes a motor, a drive mechanism, a tool body, an outer housing, a guide portion, and a handle. The drive mechanism is configured to linearly drive at least a tip tool along a drive shaft in response to driving of the motor. The tool body houses the motor and the drive mechanism. The outer housing is elastically connected to the tool body so as to cover at least a part of the tool body and is slidable in a first direction substantially parallel to the drive shaft with respect to the tool body. The guide portion is configured to guide sliding of the outer housing with respect to the tool body. The handle includes a grip portion extending in a second direction crossing the first direction. The handle is elastically connected to at least the outer housing and is movable in the first direction and at least one direction crossing the first direction, relative to the outer housing.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an impact tool configured to strike an accessory tool to linearly drive it. [Background technology]

[0002] An impact tool performs a processing operation (e.g., a chipping operation) on a workpiece by striking the tool bit and driving it linearly along the drive shaft. Therefore, the impact tool generates large vibrations during processing. Therefore, vibration-damping measures to suppress the transmission of vibrations from the tool body to the handle of the impact tool are known. For example, the impact tool disclosed in Patent Document 1 includes an outer housing connected to the tool body via a first elastic member, and a handle connected to the outer housing via a second elastic member. The outer housing is movable relative to the tool body in a direction intersecting the longitudinal axis of the tool bit, and the handle is movable relative to the outer housing in the longitudinal axis direction of the tool bit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-247239 Summary of the Invention [Problem to be solved by the invention]

[0004] The impact tool described above can handle vibrations in the longitudinal direction of the tool bit and in a direction intersecting the longitudinal direction. However, there is room for further improvement in this impact tool.

[0005] In view of the above circumstances, one non-limiting object of the present disclosure is to provide an improvement in the vibration-proof structure of an impact tool. [Means for solving the problem]

[0006] According to one non-limiting aspect of the present disclosure, there is provided an impact tool including a motor, a drive mechanism, a tool body, an outer housing, a guide portion, and a handle. The drive mechanism is operably connected to the motor and configured to linearly drive at least a tool accessory along a drive shaft in response to driving of the motor. The tool body houses the motor and the drive mechanism. The outer housing is elastically connected to the tool body so as to cover at least a portion of the tool body and is slidable relative to the tool body in a first direction substantially parallel to the drive shaft. The guide portion is configured to guide sliding of the outer housing relative to the tool body. The handle includes a grip portion extending in a second direction intersecting the first direction. The handle is elastically connected to at least the outer housing and is movable relative to the outer housing in the first direction and at least one direction intersecting the first direction.

[0007] The impact tool of this aspect includes a tool body, an outer housing, and a handle. When the bit is driven along the drive shaft, the largest and most dominant vibration occurs in a first direction substantially parallel to the drive shaft. The tool body and the outer housing are elastically connected to be slidable in the first direction. Therefore, transmission of vibration in the first direction from the tool body to the outer housing can be effectively suppressed. Furthermore, the handle and the outer housing are elastically connected to be movable in the first direction. Therefore, even if vibration in the first direction is transmitted from the tool body to the outer housing, transmission of the vibration to the handle can be suppressed. This effectively suppresses transmission of vibration in the first direction from the tool body to the handle. Furthermore, the handle and the outer housing are elastically connected to be movable in at least one direction intersecting the first direction. Therefore, even if vibration in a direction intersecting the first direction is transmitted from the tool body to the outer housing, transmission of the vibration to the handle can be suppressed.

[0008] According to another non-limiting aspect of the present disclosure, there is provided an impact tool including a motor, a drive mechanism, a tool body, an outer housing, a guide portion, and a handle. The drive mechanism is operably coupled to the motor and configured to linearly drive at least a tool accessory along a drive shaft in response to driving of the motor. The tool body houses the motor and the drive mechanism. The outer housing is elastically coupled to the tool body so as to cover at least a portion of the tool body and is slidable relative to the tool body in a first direction substantially parallel to the drive shaft. The guide portion is configured to guide sliding of the outer housing relative to the tool body. The handle includes a grip portion extending in a second direction intersecting the first direction, a first end connected to one end of the grip portion, and a second end connected to the other end of the grip portion. Each of the first and second ends of the handle is elastically coupled to the tool body or the outer housing so as to be movable in at least the first direction relative to the tool body or the outer housing. At least one of the first end and the second end is resiliently connected to the outer housing.

[0009] The impact tool of this aspect includes a tool body, an outer housing, and a handle. When the bit is driven along the drive shaft, the largest and most dominant vibration occurs in a first direction substantially parallel to the drive shaft. The tool body and the outer housing are elastically connected to each other so as to be slidable in the first direction. This effectively suppresses transmission of vibration in the first direction from the tool body to the outer housing. Furthermore, because both the first and second ends of the handle are elastically connected to the tool body or the outer housing so as to be movable in the first direction, transmission of vibration in the first direction from the tool body to the handle directly or via the outer housing can be further effectively suppressed. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a hammer drill according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3]FIG. 3 is a partially enlarged view of FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 2 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a partially enlarged view of FIG. 5. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 6 is a partial cross-sectional view of a hammer drill according to a second embodiment. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. [Figure 10] FIG. 9 is a cross-sectional view taken along line XX in FIG. 8. [Figure 11] FIG. 10 is a partial cross-sectional view of a hammer drill according to a third embodiment. [Figure 12] FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. [Figure 13] FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] In one non-limiting embodiment of the present disclosure, the outer housing may be movable relative to the tool body in at least one direction intersecting the first direction. According to this embodiment, transmission of vibrations from the tool body to the outer housing in a direction intersecting the first direction can be suppressed, thereby improving the vibration damping effect.

[0012] In addition to or instead of the above embodiment, the tool body and the outer housing may be connected by a first elastic member to allow relative movement in a first direction, and may be connected by a second elastic member separate from the first elastic member to allow relative movement in at least one direction intersecting the first direction. According to this embodiment, by utilizing the separate first elastic member and second elastic member, a rational connection structure between the tool body and the outer housing that can accommodate vibrations in multiple directions can be realized.

[0013] In addition to or instead of the above embodiment, the first elastic member may be a mechanical spring. The second elastic member may be rubber or an elastic synthetic resin. Examples of elastic synthetic resins include elastomers and synthetic resin foams (e.g., urethane foam). According to this embodiment, the largest and most dominant vibration in the first direction can be addressed by a mechanical spring suitable for isolating vibration in one direction, and vibration in other directions that are not as large as the first direction can be addressed by rubber or an elastic synthetic resin, which has a high degree of freedom in terms of shape, etc.

[0014] In addition to or instead of the above embodiment, the outer housing and the handle may be connected by a third elastic member to allow relative movement in a first direction, and may be connected by a fourth elastic member separate from the third elastic member to allow relative movement in at least one direction intersecting the first direction. According to this embodiment, by utilizing the separate third elastic member and fourth elastic member, a rational connection structure between the outer housing and the handle that can accommodate vibrations in multiple directions can be realized.

[0015] In addition to or instead of the above embodiment, the third elastic member may be a mechanical spring. The fourth elastic member may be rubber or an elastic synthetic resin. Examples of elastic synthetic resins include elastomers and synthetic resin foams (e.g., urethane foam). According to this embodiment, the largest and most dominant vibration in the first direction can be handled by a mechanical spring suitable for vibration isolation in one direction, and vibration in other directions that are not as large as the first direction can be handled by rubber or an elastic synthetic resin, which has a high degree of freedom in terms of shape, etc.

[0016] In addition to or instead of the above embodiment, the outer housing and the handle may be connected by a fourth elastic member to allow relative movement in the second direction. The fourth elastic member may be supported by a support member. The support member may be configured to restrict movement of the handle relative to the outer housing in a third direction perpendicular to the first and second directions. When the tool bit is driven, relatively large vibrations may also occur in the second direction, although these vibrations are smaller than those in the first direction. On the other hand, vibrations in the third direction perpendicular to the first and second directions are relatively small. According to this embodiment, unnecessary relative movement of the handle in the third direction can be suppressed while effectively suppressing transmission of vibrations in the second direction to the handle.

[0017] In addition to or instead of the above embodiment, the handle may include a first end connected to an end of the grip portion closer to the drive shaft and a second end connected to an end of the grip portion farther from the drive shaft in the second direction. Each of the first end and the second end may be elastically coupled to the tool body or the outer housing so as to be movable in the first direction. At least one of the first end and the second end may be elastically coupled to the outer housing. According to this embodiment, since both the first end and the second end of the handle are movable in the first direction, it is possible to effectively suppress transmission of the largest and most dominant vibration in the first direction to the handle.

[0018] In addition to or instead of the above embodiment, the first end may be elastically coupled to the outer housing. The second end may be elastically coupled to the tool body. According to this embodiment, the first end of the handle, which is closer to the drive shaft, is elastically coupled to the tool body via the outer housing so as to be relatively movable in the first direction. This effectively suppresses transmission of the largest and most dominant vibration in the first direction to the first end.

[0019] In addition to or instead of the above embodiment, the first end and the second end may each be elastically connected to the tool body or the outer housing by a mechanical spring. The preload of the mechanical spring at the first end may be greater than the preload of the mechanical spring at the second end. A machining operation using the impact tool is performed with the tool bit pressed against the workpiece. According to this embodiment, by making the preload of the mechanical spring corresponding to the first end closer to the drive shaft greater, the pressing of the tool bit against the workpiece can be stabilized.

[0020] In addition to or instead of the above embodiment, each of the first end and the second end may be elastically coupled to the tool body or the outer housing by rubber or an elastic synthetic resin so as to be movable in a first direction, a second direction, and a third direction perpendicular to the first and second directions. According to this embodiment, both the first end and the second end of the handle are movable in the first direction, the second direction, and the third direction, thereby realizing an impact tool that can respond to vibrations in various directions.

[0021] In addition to or instead of the above embodiment, the rubber or elastic synthetic resin may be annular and disposed around the shaft extending in the third direction. According to this embodiment, with a simple configuration, each of the first end and the second end can be moved in a direction intersecting the third direction relative to the tool body or the outer housing.

[0022] In addition to or instead of the above embodiment, the first end may be elastically coupled to the tool body or the outer housing by a mechanical spring. The second end may be rotatable relative to the tool body or the outer housing about an axis extending in a third direction perpendicular to the first and second directions. According to this embodiment, the mechanical spring can effectively reduce transmission of the largest and most dominant vibration in the first direction to the first end while allowing the second end, which is farther from the drive shaft, to rotate relative to the tool body or the outer housing.

[0023] Hereinafter, non-limiting and representative first to third embodiments of the present disclosure will be specifically described with reference to the drawings. In the description of the second and third embodiments, the same reference numerals as in the first embodiment will be used to designate components that are substantially the same as those in the first embodiment, and illustrations and descriptions will be omitted or simplified as appropriate. Features different from the first embodiment will mainly be described.

[0024] First Embodiment A hammer drill 1A according to a first embodiment of the present disclosure will be described in detail with reference to Figures 1 to 7. The hammer drill 1A is an example of an impact tool, and is configured to perform an operation of linearly reciprocating a removably attached bit 91 along a drive axis DX (hereinafter referred to as an impact operation). The hammer drill 1A can also perform an operation of rotating the bit 91 around the drive axis DX (hereinafter referred to as a rotation operation).

[0025] First, the general configuration of the hammer drill 1A will be described.

[0026] As shown in FIG. 1, the hammer drill 1A includes a motor 2, a drive mechanism 3 driven by the motor 2 to drive a tool bit 91, and a tool body 5A accommodating the motor 2 and the drive mechanism 3.

[0027] In this embodiment, the motor 2 is disposed so that the rotation axis RX of the motor shaft 25 extends in a direction intersecting (specifically, perpendicular to) the drive axis DX. The tool body 5A is formed by connecting a drive mechanism housing section 51, which houses the drive mechanism 3 and extends along the drive axis DX, and a motor housing section 57, which houses the motor 2, in a substantially L-shape. A tool holder 36 is disposed within one end of the drive mechanism housing section 51 in the extension direction of the drive axis DX. The tool holder 36 holds the tool bit 91 so that it can move along the drive axis DX relative to the tool holder 36 but cannot rotate around the drive axis DX.

[0028] The hammer drill 1A also includes an outer housing 6A and a handle 7A. The outer housing 6A extends along the drive axis DX so as to cover the drive mechanism housing 51 of the tool body 5A. The motor housing 57 of the tool body 5A is not covered by the outer housing 6A and is exposed to the outside. The outer housing 6A is elastically connected to the tool body 5A and is movable relative to the tool body 5A. The handle 7A is formed in a U-shape as a whole. One end of the handle 7A is elastically connected to the outer housing 6A, and the other end of the handle 7A is elastically connected to the tool body 5A (motor housing 57). The handle 7A is movable relative to the tool body 5A and the outer housing 6A. In this embodiment, "elastically connected" is synonymous with "connected via at least one elastic member."

[0029] The handle 7A includes a long grip portion 71. The grip portion 71 is disposed on the opposite side of the tool body 5A and the outer housing 6A from the tool bit 91 in the extension direction of the drive axis DX, and extends in a direction intersecting the drive axis DX. In this embodiment, the extension direction of the grip portion 71 is substantially parallel to the extension direction of the rotation axis RX of the motor 2. A switch lever 711 that is pressed by a user is provided at one end of the grip portion 71 in the longitudinal direction. When the switch lever 711 is pressed, the motor 2 starts to be driven, the tool bit 91 is driven by the drive mechanism 3, and a processing operation (e.g., chipping or drilling) is performed.

[0030] The detailed configuration of the hammer drill 1A will be described below. For convenience, in the following description, the direction in which the drive axis DX extends (hereinafter simply referred to as the drive axis direction) will be defined as the front-rear direction of the hammer drill 1A. In the front-rear direction, the side on which the tool holder 36 is arranged will be defined as the front side of the hammer drill 1A, and the side on which the grip portion 71 is arranged will be defined as the rear side. Furthermore, the longitudinal direction of the grip portion 71 (which is also the direction in which the rotation axis RX extends) will be defined as the up-down direction of the hammer drill 1A. In the up-down direction, the side on which the switch lever 711 is arranged will be defined as the upper side, and the opposite side will be defined as the lower side. Furthermore, the direction perpendicular to the front-rear direction and the up-down direction will be defined as the left-right direction.

[0031] First, the tool body 5A and the elements (configuration) arranged therein will be described.

[0032] As shown in FIG. 1, the tool body 5A includes a drive mechanism housing portion 51 and a motor housing portion 57 connected to the drive mechanism housing portion 51.

[0033] The front half of drive mechanism accommodating portion 51 is formed in a generally cylindrical shape and is also referred to as barrel portion 52. The rear half of drive mechanism accommodating portion 51 is formed as a generally rectangular hollow body and is also referred to as crank housing 53. Barrel portion 52 and crank housing 53 are integrally connected and fixed to each other in the front-rear direction by screws (not shown) to form drive mechanism accommodating portion 51.

[0034] The drive mechanism housing 51 houses the drive mechanism 3. The drive mechanism 3 is operably connected to the motor 2 (motor shaft 25) and is driven by the power of the motor 2. The drive mechanism 3 of this embodiment includes a striking mechanism 30 for striking operation and a rotation transmission mechanism 35 for rotating operation. Note that the configurations of these mechanisms are well known, so they will be briefly described below.

[0035] The impact mechanism 30 includes a motion conversion mechanism and an impact element. The motion conversion mechanism is operably connected to the motor 2 and is configured to convert the rotational motion of the motor shaft 25 into linear motion and transmit it to the impact element. In this embodiment, the motion conversion mechanism uses a well-known crank mechanism including a crankshaft and a piston. The impact element moves linearly to strike the tool bit 91, thereby driving the tool bit 91 linearly along the drive axis DX. In this embodiment, the impact element includes a striker and an impact bolt. When the motor 2 is driven, the piston reciprocates back and forth along the drive axis DX within a cylinder disposed in the drive mechanism housing 51. The reciprocating movement of the piston drives the impact element by the action of an air spring, causing the tool bit 91 to intermittently strike the impact bolt.

[0036] The rotation transmission mechanism 35 is operably connected to the motor 2 and configured to transmit the rotational power of the motor shaft 25 to the tool holder 36. The rotation transmission mechanism 35 of this embodiment is a gear reduction mechanism having a well-known configuration, and the rotational power of the motor 2 is appropriately reduced before being transmitted to the tool holder 36. When the motor 2 is driven, the rotation transmission mechanism 35 causes the tool holder 36, and ultimately the tool bit 91 held by the tool holder 36, to rotate about the drive axis DX.

[0037] The hammer drill 1A of this embodiment can be selectively operated in either a mode in which only a striking operation is performed or a mode in which a striking operation and a rotating operation are simultaneously performed. Any known configuration may be employed for switching between modes. Therefore, a description of such a configuration will be omitted.

[0038] 2, in this embodiment, the drive mechanism housing 51 is provided with two dynamic vibration absorbers 37 for absorbing vibrations generated in the tool body 5A. The two dynamic vibration absorbers 37 are arranged symmetrically with respect to an imaginary plane P that includes the drive axis DX and is perpendicular to the left-right direction. The plane P is a plane that passes through the substantial center of the hammer drill 1A in the left-right direction. The plane P also includes the drive axis DX and the rotation axis RX.

[0039] Each dynamic vibration absorber 37 includes a weight 371, two springs 372 arranged on either side of the weight 371, and a housing portion 373 that houses the weight 371 and the springs 372. The weight 371 and the springs 372 are arranged inside the housing portion 373 that is integrated with the drive mechanism housing portion 51 (crank housing 53), in a state in which the weight 371 is slidable while receiving the biasing force of the springs 372. The dynamic vibration absorber 37 can effectively absorb vibrations in the front-rear direction that occur during an impact operation.

[0040] 1, the motor housing 57 is formed in a cylindrical shape with a bottom and an open top. The drive mechanism housing 51 and the motor housing 57 are integrally connected and fixed with screws, with the lower end of the drive mechanism housing 51 disposed within the upper end of the motor housing 57, to form the tool main body 5A.

[0041] The motor accommodating section 57 accommodates the motor 2. The motor 2 in this embodiment is a brush motor. The motor 2 is driven by power supplied from an external AC power source via a power cord 29. The motor 2 includes a stator 21, a rotor 23, and a motor shaft 25 configured to rotate integrally with the rotor 23. The motor shaft 25 extends in the vertical direction. The upper and lower ends of the motor shaft 25 are rotatably supported by bearings 251 and 252, respectively, supported by the tool body 5A.

[0042] A fan 27 is fixed to the lower end of the motor shaft 25. In this embodiment, the fan 27 is fixed to the motor shaft 25 below the bearing 252 and is disposed within the lowest end of the motor housing portion 57. The fan 27 rotates integrally with the motor shaft 25 in response to the driving of the motor 2, and is configured to generate an airflow for cooling the motor 2.

[0043] The outer housing 6A will now be described.

[0044] 1, the outer housing 6A is configured to cover the drive mechanism accommodating portion 51 of the tool main body 5A. More specifically, the front half of the outer housing 6A is formed in a cylindrical shape and covers the front half (barrel portion 52) of the drive mechanism accommodating portion 51. The rear half of the outer housing 6A is formed in a rectangular box shape with an open bottom end and covers the rear half (crank housing 53) of the drive mechanism accommodating portion 51. A lower end of a peripheral wall portion 61 of the rear half of the outer housing 6A is configured to correspond to a peripheral wall portion 571 of the motor accommodating portion 57.

[0045] The connecting structure between the tool body 5A and the outer housing 6A will be described below.

[0046] In this embodiment, the tool body 5A and the outer housing 6A are elastically connected to each other so as to be slidable relative to each other substantially parallel to the drive axis DX (i.e., in the front-to-rear direction). The tool body 5A and the outer housing 6A are also elastically connected to each other so as to be movable relative to each other in a direction intersecting the drive axis DX. In this embodiment, as shown in FIGS. 1, 3, and 4, two springs 81A, two elastic members 82A, and an O-ring 83 are interposed between the tool body 5A and the outer housing 6A.

[0047] In this embodiment, the spring 81A is a compression coil spring, an example of a mechanical spring. The spring 81A is disposed in a compressed state between the rear end of the drive mechanism housing 51 (crank housing 53) and the rear end of the outer housing 6A. More specifically, the front end of the spring 81A is fitted into and supported by a spring receiver 374 (protrusion) provided at the rear end of the housing 373 of the dynamic vibration absorber 37. The rear end of the spring 81A is fitted into and supported by a spring receiver 612 (protrusion) provided on the inner surface of the rear wall 611 of the outer housing 6A. The spring 81A biases the tool main body 5A and the outer housing 6A away from each other in the front-rear direction (forward and rearward, respectively), allowing relative movement therebetween. In this embodiment, the two springs 81A are disposed symmetrically on both sides of the plane P.

[0048] The elastic member 82A in this embodiment is made of urethane foam. A screw 423 is fixed to the rear wall 511 of the drive mechanism accommodating portion 51 (crank housing 53) and extends rearward. The elastic member 82A is cylindrical and is fitted around and held in place by the shank of the screw 423. A cylindrical cover 421 with a bottom is placed over the elastic member 82A. The cover 421 is made of metal and covers the outer circumferential surface of the elastic member 82A. The elastic member 82A is interposed between the shank of the screw 423 and the cover 421 in a direction intersecting the axis of the screw 423 (i.e., in all directions other than the radial direction of the screw 423, the direction intersecting the drive axis DX, and the front-rear direction). The elastic member 82A allows the screw 423 to move relative to the cover 421 in all directions intersecting the axis of the screw 423.

[0049] O-ring 83 is an annular member made of rubber. O-ring 83 is fitted in an annular groove formed on the outer periphery of barrel portion 52 of drive mechanism accommodating portion 51, and is interposed between barrel portion 52 and the front half portion (cylindrical wall portion) of outer housing 6A in the radial direction of barrel portion 52. O-ring 83 allows barrel portion 52 to move in all directions relative to outer housing 6A.

[0050] In this embodiment, the tool body 5A and the outer housing 6A are configured to be relatively slidable in the front-rear direction.

[0051] 1 and 4, in the tool body 5A, an upper end surface 411 of the peripheral wall portion 571 of the motor accommodating portion 57 and a lower end surface 415 of the peripheral wall portion 61 of the outer housing 6A are sliding surfaces that are in contact with each other and can slide against each other. In this embodiment, the upper end surface 411 and the lower end surface 415 form a first guide portion 41 that guides the relative sliding movement between the tool body 5A and the outer housing 6A in the front-to-rear direction.

[0052] 3 and 4, two cylindrical guide tubes 425 are provided on the rear wall 611 of the outer housing 6A. The two guide tubes 425 are symmetrically arranged on both sides of the plane P so as to correspond to the two elastic members 82A. The guide tubes 425 protrude forward from the inner surface of the rear wall 611. The guide tubes 425 have an inner diameter that is approximately equal to the outer diameter of the cover 421. Therefore, the cover 421 can slide in the front-rear direction within the guide tubes 425. The cover 421 and the guide tubes 425 form a second guide portion 42 that guides the relative sliding movement of the tool main body 5A and the outer housing 6A in the front-rear direction.

[0053] As described above, with the elastic force of the spring 81A acting on the tool body 5A and the outer housing 6A, they are able to slide relatively in the front-to-rear direction while being guided by the first guide portion 41 and the second guide portion 42. Furthermore, with the elastic force of the elastic member 82A and the O-ring 83 acting on the tool body 5A and the outer housing 6A, they are also able to move relatively in directions intersecting the drive axis DX (for example, up-down and left-right directions). This effectively suppresses transmission of vibrations in the front-to-rear direction and in directions intersecting the drive axis DX from the tool body 5A to the outer housing 6A.

[0054] The handle 7A and the elements (configuration) arranged therein will be described below.

[0055] As shown in Fig. 4, the handle 7A of this embodiment includes a grip portion 71, an upper connecting portion 73A, and a lower connecting portion 76A. The upper connecting portion 73A is connected to the upper end of the grip portion 71 and protrudes slightly forward of the grip portion 71. The upper connecting portion 73A is elastically connected to the outer housing 6A. The lower connecting portion 76A is connected to the lower end of the grip portion 71 and protrudes slightly forward of the grip portion 71. The lower connecting portion 76A is elastically connected to the tool main body 5A.

[0056] A long switch lever 711 is disposed at the upper end of the grip portion 71 of the handle 7A. The switch lever 711 is supported at its lower end by the grip portion 71 and is rotatable generally in the front-to-rear direction. The switch lever 711 is biased forward and rotates rearward in response to a pressing operation by the user. A switch 713 is housed within the grip portion 71. The switch 713 is normally maintained in the OFF state and is turned ON in response to pressing of the switch lever 711. The switch 713 is connected to the motor 2 by an electric wire (not shown), and the motor 2 is driven while the switch 713 is in the ON state.

[0057] The connecting structure between the handle 7A, the outer housing 6A and the tool body 5A will be described below.

[0058] First, the connection structure between the upper connecting portion 73A and the outer housing 6A will be described. In this embodiment, the upper connecting portion 73A and the outer housing 6A are elastically connected to each other so as to be relatively movable substantially parallel to the drive axis DX (i.e., in the front-to-rear direction). The upper connecting portion 73A and the outer housing 6A are also elastically connected to each other so as to be relatively movable in a direction intersecting the drive axis DX. More specifically, as shown in FIGS. 3, 4, and 6, two springs 84A and two elastic members 85A are interposed between the upper connecting portion 73A and the outer housing 6A.

[0059] In this embodiment, a compression coil spring, an example of a mechanical spring, is used as the spring 84A. The spring 84A is disposed in a compressed state between the rear wall portion 611 of the peripheral wall portion 61 of the outer housing 6A and the upper connecting portion 73A of the handle 7A. More specifically, the front end of the spring 84A is fitted into and supported by a spring receiver 614 provided on the rear surface of the rear wall portion 611. The rear end of the spring 84A is fitted into and supported by a spring receiver 731 provided on the front surface of the upper connecting portion 73A. The spring 84A biases the outer housing 6A and the upper connecting portion 73A (handle 7A) away from each other in the front-rear direction (forward and rearward, respectively), allowing relative movement therebetween. In this embodiment, the two springs 84A are disposed symmetrically on both sides of the plane P.

[0060] The spring bearing 614 of the outer housing 6A is a cylindrical portion that protrudes rearward from the rear wall portion 611 and has a guide hole 431 that penetrates the spring bearing 614 in the front-rear direction. The guide hole 431 is defined by two parallel surfaces and two curved surfaces that are parallel to each other. In other words, the guide hole 431 is a hole with a double-D shaped cross section. The two parallel surfaces of the guide hole 431 are substantially perpendicular to the left-right direction. One of the two curved surfaces connects the upper ends of the two parallel surfaces, and the other curved surface connects the lower ends of the two parallel surfaces.

[0061] The spring receiver 731 of the handle 7A is a protrusion that protrudes forward from the upper connecting portion 73A. A guide shaft 432 protrudes forward from the center of the spring receiver 731. A screw hole 433 that extends in the front-to-rear direction is formed in the guide shaft 432 and the spring receiver 731.

[0062] The guide shaft 432 is configured to be insertable into the guide hole 431 of the spring bearing 614. More specifically, the outer circumferential surface of the guide shaft 432 includes two parallel surfaces parallel to each other and two curved surfaces. In other words, the guide shaft 432 is a shaft having a double-D cross section. The width of the guide shaft 432 in the left-right direction (the distance between the parallel surfaces) is approximately equal to the width of the guide hole 431 in the left-right direction (the distance between the parallel surfaces). Meanwhile, in the up-down direction, the height of the guide shaft 432 in the up-down direction (the distance between the curved surfaces) is set to be greater than the height of the guide hole 431 in the up-down direction (the distance between the curved surfaces). In other words, the guide hole 431 has a clearance in the up-down direction.

[0063] With spring 84A supported by spring receiver 731 and spring receiver 614 and guide shaft 432 inserted into guide hole 431, upper connecting portion 73A and outer housing 6A are connected by screw 435 fastened into screw hole 433 from the inside of rear wall portion 611. Note that while part of spring receiver 614 and screw 435 are not shown in Fig. 3, the connecting structure between upper connecting portion 73A and outer housing 6A is substantially the same as the connecting structure between lower connecting portion 76A and outer housing 6A shown in Fig. 7.

[0064] With the above-described configuration, the guide shaft 432 is restricted in its movement only in the left-right direction and is slidable in the front-rear and up-down directions (including when the axis of the guide shaft 432 is inclined up-down relative to the drive shaft DX) within the guide hole 431. The guide hole 431 and the guide shaft 432 form a third guide part 43 that guides the relative movement between the upper connecting part 73A and the outer housing 6A.

[0065] The elastic member 85A is made of urethane foam. As shown in FIGS. 3, 4, and 6, the elastic member 85A is supported by a guide member 74 fixed to the handle 7A. The guide member 74 is fixed to the upper connecting portion 73A of the handle 7A with screws 749 and extends forward from the upper connecting portion 73A along the plane P. In this embodiment, the guide member 74 is a plate-like member having a thickness in the left-right direction. Two shaft portions 742 protrude to the left and right from the front end portion 441 of the guide member 74. The shaft portions 742 are symmetrically disposed on both sides of the plane P in the left-right direction. The shaft portions 742 are disposed at approximately the same position as the third guide portion 43 in the up-down direction.

[0066] The elastic member 85A is cylindrical and is fitted around and held by the shaft portion 742. Therefore, the two elastic members 85A are arranged symmetrically on both sides of the plane P. A cylindrical cover 442 with a bottom is placed over the elastic member 85A. The cover 442 is made of metal and covers the outer circumferential surface of the elastic member 85A. The elastic member 85A is interposed between the shaft portion 742 and the cover 442 in all directions intersecting the axis of the shaft portion 742 (i.e., the radial direction of the shaft portion 742, the direction intersecting the left-right direction, and all directions other than the left-right direction). The elastic member 85A allows the shaft portion 742 to move relative to the cover 442 in all directions intersecting the axis of the shaft portion 742.

[0067] It is preferable in terms of reducing manufacturing costs that the elastic member 85A and the cover 442 are made of substantially the same materials as the above-described elastic member 82A and cover 421. However, the configurations (e.g., shapes, materials) of the elastic member 85A and the cover 442 may differ from those of the elastic member 82A and the cover 421 depending on the desired vibration-damping characteristics.

[0068] Meanwhile, a guide passage 445 is defined in the rear wall 611 of the outer housing 6A. The guide passage 445 is a passage that penetrates the rear wall 611 and accommodates the front end 441 of the guide member 74, the elastic member 85A supported by the shaft portion 742, and the cover 442 so that they can move in the front-rear direction relative to the outer housing 6A. More specifically, the guide passage 445 includes a first portion 446 in which the front end 441 of the guide member 74 is disposed, and two second portions 447 in which the cover 442 is disposed.

[0069] The width of the first portion 446 in the left-right direction is approximately equal to the thickness of the front end portion 441 in the left-right direction. On the other hand, the height of the first portion 446 in the up-down direction is set to be greater than the height of the front end portion 441 in the up-down direction. In other words, a clearance in the up-down direction is provided in the first portion 446. The width of the second portion 447 in the left-right direction is approximately equal to the thickness of the cover 442 in the left-right direction. In addition, the height of the second portion 447 in the up-down direction is also approximately equal to the height of the cover 442 in the up-down direction. In other words, no clearance in the up-down direction is provided in the second portion 447.

[0070] With the above-described configuration, the guide member 74 is movable within the guide passage 445 while its movement in the left-right direction is restricted. More specifically, the front end portion 441 of the guide member 74 is slidable within the first portion 446 in the front-rear and up-down directions (including when the axis of the screw 749 is inclined vertically relative to the drive shaft DX) while its movement in the left-right direction is restricted. Furthermore, the cover 442, which is fitted to the shaft portion 742 via the elastic member 85A, is slidable within the second portion 447 in the front-rear and up-down directions while its movement in the left-right and up-down directions is restricted. Meanwhile, the elastic member 85A allows the shaft portion 742 (guide member 74) to move within the second portion 447 in the front-rear and up-down directions. The guide passage 445, the guide member 74 (front end portion 441), and the cover 442 constitute a fourth guide portion 44 that guides the relative movement between the upper connecting portion 73A and the outer housing 6A.

[0071] As described above, the upper connecting portion 73A and the outer housing 6A are slidable relative to each other in the front-rear direction while being guided by the third guide portion 43 and the fourth guide portion 44 under the action of the elastic force of the spring 84A. Furthermore, the upper connecting portion 73A and the outer housing 6A are movable relative to each other in directions other than the left-right direction under the action of the elastic force of the elastic member 85A. Therefore, even if vibrations in the front-rear direction and in directions other than the left-right direction (e.g., up-down direction) are transmitted from the tool body 5A to the outer housing 6A, the transmission of the vibrations to the handle 7A can be suppressed. This effectively suppresses transmission of vibrations in various directions from the tool body 5A to the handle 7A.

[0072] The connection structure between the lower connecting part 76A and the tool body 5A will be described below. In this embodiment, the lower connecting part 76A and the tool body 5A are elastically connected to each other so as to be relatively movable substantially parallel to the drive axis DX (i.e., in the front-rear direction). More specifically, as shown in FIGS. 4 and 7, two springs 86A are interposed between the lower connecting part 76A and the tool body 5A. The two springs 86A are arranged symmetrically on both sides of the plane P.

[0073] In this embodiment, a compression coil spring, which is an example of a mechanical spring, is used as the spring 86A. The spring 86A is disposed in a compressed state between a rear wall portion 572 of the motor housing portion 57 of the tool body 5A and the lower connecting portion 76A of the handle 7A. More specifically, the front end of the spring 86A is fitted into and supported by a spring receiver 573 provided on the rear surface of the rear wall portion 572. The rear end of the spring 86A is fitted into and supported by a spring receiver 761 provided on the front surface of the lower connecting portion 76A. The spring 86A biases the tool body 5A and the lower connecting portion 76A (handle 7A) so as to move away from each other in the front-rear direction (forward and backward, respectively), allowing relative movement therebetween in the front-rear direction.

[0074] The spring receiver 573 of the tool main body 5A has substantially the same configuration as the spring receiver 614 of the outer housing 6A described above. Furthermore, the spring receiver 761 of the lower connecting portion 76A has substantially the same configuration as the spring receiver 731 of the upper connecting portion 73A described above. Briefly, as shown in FIGS. 4, 5, and 7, the spring receiver 573 is a cylindrical portion that protrudes rearward from the rear wall portion 572 and has a guide hole 451 with a double-D cross section. The spring receiver 761 is a protrusion that protrudes forward from the lower connecting portion 76A and has a guide shaft 452 with a double-D cross section. The guide hole 451 has a clearance in the vertical direction. The lower connecting portion 76A and the tool body 5A are connected by a screw 455 tightened into the screw hole 454 from the inside of the rear wall portion 572, with the spring 86A supported by the spring receiver 761 and the spring receiver 573 and the guide shaft 452 inserted into the guide hole 451.

[0075] With the above-described configuration, the guide shaft 452 is restricted in its movement only in the left-right direction and is slidable in the front-rear and up-down directions (including when the axis of the guide shaft 452 is inclined up-down relative to the drive axis DX) within the guide hole 451. The guide hole 451 and the guide shaft 452 form a fifth guide part 45 that guides the relative movement between the lower connecting part 76A and the tool body 5A.

[0076] In this embodiment, the spring 86A has substantially the same specifications as the spring 84A interposed between the outer housing 6A and the upper connecting portion 73A. In other words, the springs 84A and 86A are compression coil springs of the same shape, made of the same material, and have the same spring constant. However, the springs 84A and 86A are attached to the outer housing 6A and the upper connecting portion 73A in different ways. More specifically, of the springs 84A and 86A, the spring 84A, which is closer to the drive shaft DX, is attached with a larger initial load (also referred to as an attachment load) than the spring 86A (see FIG. 4). The term "state with an initial load applied" refers to a state in which a load is applied to the elastic member in a compressive direction in a static state, compressing the elastic member.

[0077] A machining operation using the hammer drill 1A is performed with the bit 91 pressed against the workpiece. Therefore, by increasing the initial load (strengthening the biasing force) of the spring 84A that connects the upper connecting portion 73A, which is closer to the drive shaft DX, to the outer housing 6A, the pressing of the bit 91 against the workpiece can be stabilized. Furthermore, by decreasing the initial load (weakening the biasing force) of the spring 86A that connects the motor housing portion 57 to the lower connecting portion 76A, the vibration damping effect can be improved. Thus, in this embodiment, vibration damping is optimized by setting the initial loads of the springs 84A and 86A as described above.

[0078] In another embodiment, spring 86A may be a spring having a smaller spring constant than spring 84A, and the attachment state of spring 84A and spring 86A may be substantially the same. In this case, too, the same effect as when the initial loads of springs 84A and 86A are set as described above can be obtained.

[0079] 1, 4, and 5, a guide member 77 is fixed to the lower connecting portion 76A. The guide member 77 is fixed to the lower connecting portion 76A with a screw 773 and extends forward from the lower connecting portion 76A along the plane P. The guide member 77 is a plate-like member that has a thickness in the left-right direction, similar to the guide member 74 fixed to the upper connecting portion 73A. However, the guide member 77 does not include a shaft portion.

[0080] Meanwhile, a guide passage 465 is provided in the rear wall 572 of the motor housing 57 of the tool body 5A. The guide passage 465 is a passage that penetrates the rear wall 572 and accommodates the front end 461 of the guide member 77 so that it can move in the front-rear direction relative to the tool body 5A. The left-right width of the guide passage 465 is approximately equal to the left-right thickness of the front end 461. The vertical height of the guide passage 465 is set to be greater than the vertical height of the front end 461. In other words, the guide passage 465 has a clearance in the up-down direction.

[0081] With the above-described configuration, the guide member 77 is slidable in the front-rear and up-down directions (including when the axis of the screw 773 is inclined up-down relative to the drive axis DX) within the guide passage 465 while its movement in the left-right and up-down directions is restricted. The guide passage 465 and the guide member 77 (front end portion 461) form the sixth guide portion 46 that guides the relative movement between the lower connecting portion 76A and the tool body 5A.

[0082] As described above, the lower connecting portion 76A and the tool main body 5A are slidable relative to each other in the front-rear direction while being guided by the fifth guide portion 45 and the sixth guide portion 46 under the action of the elastic force of the spring 86A. This effectively prevents vibrations in the front-rear direction from being transmitted from the tool main body 5A to the handle 7A. Note that, although no elastic member is interposed between the lower connecting portion 76A and the tool main body 5A in this embodiment, an elastic member may be disposed in another embodiment, similar to the upper connecting portion 73A.

[0083] In this embodiment, the upper connecting portion 73A and the outer housing 6A, and the lower connecting portion 76A and the tool body 5A are not elastically connected in the left-right direction. This is because, in an impact tool such as the hammer drill 1A, left-right vibration is relatively small. As described above, in this embodiment, the outer housing 6A is elastically connected to the tool body 5A so as to be movable in the left-right direction, thereby reducing left-right vibration of the outer housing 6A. Therefore, with regard to the handle 7A, operability is improved by restricting left-right movement relative to the outer housing 6A and the tool body 5A.

[0084] In this embodiment, springs 81A, 84A, and 86A, which are compression coil springs suitable for vibration isolation in one direction, are used to counter the vibrations in the front-to-rear direction, which are the largest and most dominant direction. On the other hand, elastic members 82A and 85A made of urethane foam, which have a high degree of freedom in shape, are used to counter vibrations in other directions that are not as large as the front-to-rear direction. Designing these elastic members allows for optimized vibration isolation according to the characteristics of vibrations in various directions.

[0085] Second Embodiment A hammer drill 1B according to the second embodiment will be described below with reference to Figures 8 to 10. The hammer drill 1B differs from the hammer drill 1A of the first embodiment in the connection structure between the tool body 5B and the outer housing 6B, and the connection structure between the handle 7B and the outer housing 6B and the tool body 5B. However, apart from these connection structures, the hammer drill 1B has substantially the same configuration as the hammer drill 1A (including slight differences in shape).

[0086] First, the connecting structure between the tool body 5B and the outer housing 6B will be described.

[0087] In this embodiment, the tool body 5B and the outer housing 6B are elastically connected to each other so as to be slidable relative to each other substantially parallel to the drive axis DX (i.e., in the front-rear direction). The tool body 5B and the outer housing 6B are also elastically connected to each other so as to be movable relative to each other in a direction intersecting the drive axis DX. More specifically, as shown in FIGS. 8 and 9, the hammer drill 1B includes a spring 81A, an O-ring 83 (see FIG. 1), and a first guide portion 41 (see FIG. 4), similar to the first embodiment. However, the hammer drill 1B does not include an elastic member 82A or a second guide portion 42.

[0088] The connecting structure between the handle 7B, the outer housing 6B and the tool body 5B will be described below.

[0089] First, the connection structure between the upper connecting portion 73B and the outer housing 6B will be described. In this embodiment, the upper connecting portion 73B and the outer housing 6B are elastically connected to each other so as to be relatively movable in all directions, including the front-rear, up-down, and left-right directions. More specifically, as shown in FIG. 9, two elastic members 85B are interposed between the upper connecting portion 73B and the outer housing 6B.

[0090] The elastic member 85B is made of urethane foam. The elastic member 85B is supported by a shaft portion 633 provided on the outer housing 6B. The shaft portion 633 protrudes leftward and rightward from the left and right side portions 63 at the rear end of the outer housing 6B, respectively. The shaft portions 633 are arranged symmetrically on both sides of the plane P in the left-right direction. The elastic member 85B is cylindrical and is fitted around and held by the shaft portion 633. Therefore, the two elastic members 85B are arranged symmetrically on both sides of the plane P.

[0091] Meanwhile, the upper connecting portion 73B is provided with a pair of left and right extending portions 733. The extending portions 733 protrude forward to cover the left and right side portions 63 of the rear end portion of the outer housing 6B. The elastic member 85B is fitted into a recess 734 formed on the inner surface of the extending portion 733 and is interposed in a compressed state between the side portions 63 of the rear end portion of the outer housing 6B and the extending portion 733 of the upper connecting portion 73B. The outer housing 6B and the upper connecting portion 73B are maintained in a spaced-apart state in all directions. The shaft portion 633 is movable within the recess 734 in the axial direction of the shaft portion 633 (left and right direction) and in any direction intersecting the axis of the shaft portion 633 (for example, the front-rear direction and the up-down direction) while elastically deforming the elastic member 85B.

[0092] Next, the connection structure between the lower connecting portion 76B and the tool body 5B will be described. In this embodiment, the lower connecting portion 76B and the tool body 5B are elastically connected to each other so as to be relatively movable in all directions, including the front-rear direction, the up-down direction, and the left-right direction. More specifically, as shown in FIG. 10, two elastic members 88B are interposed between the lower connecting portion 76B and the tool body 5B.

[0093] The elastic member 88B is made of urethane foam. The elastic member 88B is supported by a shaft portion 576 provided on the tool body 5B. More specifically, a pair of left and right extension portions 575 is provided on the motor accommodating portion 57 of the tool body 5B. The extension portions 575 protrude rearward from the rear wall portion 572 and are inserted into the front end portion of the lower connecting portion 76B. The shaft portions 576 protrude left and right from the extension portions 575, respectively. The shaft portions 576 are symmetrically disposed on both sides of the plane P in the left-right direction. The elastic member 88B is cylindrical and is fitted around and held by the shaft portion 576. Therefore, the two elastic members 88B are symmetrically disposed on both sides of the plane P.

[0094] Meanwhile, recesses 766 are formed on the inner surfaces of the left and right side portions 765 of the front end portion of the lower connecting portion 76B. The elastic member 88B is fitted into the recesses 766 and is interposed in a compressed state between the side portions 765 of the front end portion of the lower connecting portion 76B and the extension portion 575 of the tool main body 5B. The tool main body 5B and the lower connecting portion 76B are maintained in a spaced-apart state in all directions. The shaft portion 576 is movable within the recesses 766 in the axial direction of the shaft portion 576 (left-right direction) and in any direction intersecting the axis of the shaft portion 576 (e.g., front-rear direction, up-down direction) while elastically deforming the elastic member 88B. The lower connecting portion 76B is also rotatable around the axis of the shaft portion 576 (an axis extending substantially in the left-right direction).

[0095] It should be noted that the manufacturing cost can be reduced if the elastic member 88B is substantially the same material as the above-described elastic member 85B. On the other hand, it is also possible to optimize vibration isolation by making the elastic constant of the elastic member 85B, which is closer to the drive shaft DX, larger than the elastic constant of the elastic member 88B.

[0096] As described above, in this embodiment, the tool body 5B and the outer housing 6B are also slidable relative to each other in the front-rear direction while being guided by the first guide portion 41 under the action of the elastic force of the spring 81A. This effectively prevents vibrations in the front-rear direction from being transmitted from the tool body 5B to the outer housing 6B. Furthermore, the tool body 5B and the outer housing 6B are also movable relative to each other in directions intersecting the drive axis DX (for example, the up-down direction and the left-right direction) under the action of the elastic force of the O-ring 83. This effectively prevents vibrations in the front-rear direction and in directions intersecting the drive axis DX from being transmitted from the tool body 5B to the outer housing 6B.

[0097] Furthermore, with the elastic force of the elastic member 85B acting on the upper connecting portion 73B and the outer housing 6B, they can move in the axial direction (left-right direction) of the shaft portion 633 and in any direction intersecting the axis of the shaft portion 633 (for example, the front-rear direction and the up-down direction). Therefore, even if vibrations in the front-rear direction and vibrations in directions other than the front-rear direction are transmitted from the tool body 5B to the outer housing 6B, the transmission of the vibrations to the handle 7B can be suppressed. This effectively suppresses the transmission of vibrations in various directions from the tool body 5B to the handle 7B.

[0098] Similarly, with the elastic force of the elastic member 88B acting, the lower connecting portion 76B and the tool main body 5B can move relatively in the axial direction (left-right direction) of the shaft portion 576 and in any direction intersecting the axis of the shaft portion 576 (for example, the front-rear direction and the up-down direction). This effectively prevents vibrations of the tool main body 5B from being transmitted to the handle 7B in various directions. Furthermore, the lower connecting portion 76B, which is farther from the drive shaft DX, can rotate relative to the tool main body 5B around the axis of the shaft portion 576 (an axis extending substantially in the left-right direction). Therefore, with the elastic force of the elastic member 85B acting, the upper connecting portion 73B and the outer housing 6B can move relatively in the front-rear direction, which corresponds to the largest vibration.

[0099] <Third embodiment> A hammer drill 1C according to the third embodiment will be described below with reference to Figures 11 to 13. The hammer drill 1C differs from the hammer drill 1B of the second embodiment in the connection structure between the tool body 5C and the outer housing 6C, and the connection structure between the handle 7C and the outer housing 6C and the tool body 5C. However, apart from these connection structures, the hammer drill 1C has substantially the same configuration as the hammer drill 1B (including slight differences in shape).

[0100] First, the connecting structure between the tool body 5C and the outer housing 6C will be described.

[0101] In this embodiment, the tool body 5C and the outer housing 6C are elastically connected to each other so as to be slidable relative to each other substantially parallel to the drive axis DX (i.e., in the front-rear direction). The tool body 5C and the outer housing 6C are also elastically connected to each other so as to be movable relative to each other in a direction intersecting the drive axis DX. More specifically, as shown in Figures 11 and 12, the hammer drill 1C includes a spring 81A, an O-ring 83 (see Figure 1), and a first guide portion 41 (see Figure 4), similar to the second embodiment.

[0102] The connecting structure between the handle 7C, the outer housing 6C and the tool body 5C will be described below.

[0103] First, the connection structure between the upper connecting portion 73C and the outer housing 6C will be described. In this embodiment, the upper connecting portion 73C and the outer housing 6C are elastically connected to each other so as to be relatively slidable substantially parallel to the drive shaft DX (i.e., in the front-rear direction). More specifically, as shown in Figures 11 and 12, two springs 84C are interposed between the upper connecting portion 73C and the outer housing 6C.

[0104] In this embodiment, a compression coil spring, an example of a mechanical spring, is used as the spring 84C. The spring 84C is disposed in a compressed state between the rear wall portion 611 of the outer housing 6C and the upper connecting portion 73C of the handle 7C. More specifically, the front end of the spring 84C is fitted into and supported by a spring receiver 617 (protrusion) provided on the rear surface of the rear wall portion 611. The rear end of the spring 84C is fitted into and supported by a spring receiver 737 (protrusion) provided on the front surface of the upper connecting portion 73C. The spring 84C biases the outer housing 6C and the upper connecting portion 73C (handle 7C) away from each other in the front-rear direction (forward and rearward, respectively), allowing relative movement therebetween. In this embodiment, the two springs 84C are disposed symmetrically on both sides of the plane P.

[0105] Furthermore, the hammer drill 1C is provided with a seventh guide portion 47 for guiding the sliding of the upper connecting portion 73C in the front-rear direction relative to the outer housing 6C. More specifically, the seventh guide portion 47 includes a guide hole 471 provided in the outer housing 6C and a guide shaft 472 provided in the upper connecting portion 73C.

[0106] The guide hole 471 is a hole that penetrates the rear wall portion 611 of the outer housing 6C in the front-rear direction. The guide shaft 472 protrudes forward from the upper connecting portion 73C and is inserted into the guide hole 471. The guide shaft 472 has a cross-sectional shape that substantially matches the guide hole 471. A screw hole 473 extending in the axial direction is formed in the guide shaft 472. With the guide shaft 472 inserted into the guide hole 471, the upper connecting portion 73C and the outer housing 6C are connected by a screw 475 that is fastened into the screw hole 473 from the inside of the rear wall portion 611. With the above configuration, the guide shaft 472 can slide within the guide hole 471 only in the front-rear direction. However, in another embodiment, as in the first embodiment, the guide hole 471 may be provided with a clearance in the up-down direction.

[0107] Next, the connection structure between the lower connecting portion 76C and the tool body 5C will be described. In this embodiment, the lower connecting portion 76C and the tool body 5C are elastically connected to each other so as to be relatively movable in all directions (e.g., front-rear and up-down directions) except for the left-right direction. More specifically, as shown in Fig. 13, two elastic members 88C are interposed between the lower connecting portion 76C and the tool body 5C.

[0108] The elastic member 88C is made of urethane foam. The elastic member 88C is supported by a shaft portion 768 provided on the handle 7C. The shaft portion 768 protrudes leftward and rightward from left and right side portions 767 of the front end portion of the lower connecting portion 76C, respectively. The shaft portions 768 are arranged symmetrically on both sides of the plane P in the left-right direction. The elastic member 88C is cylindrical and is fitted around and held by the shaft portion 768. Therefore, the two elastic members 88C are arranged symmetrically on both sides of the plane P.

[0109] Meanwhile, a pair of left and right extensions 577 are provided on the motor housing 57 of the tool main body 5C. The extensions 577 protrude rearward from the rear wall 572 so as to partially cover the side portions 767 of the lower connecting portion 76C. The elastic member 88C is fitted into a recess 578 formed on the inner surface of the extensions 577 and is interposed in a compressed state between the side portions 767 at the front end of the lower connecting portion 76C and the extensions 577 of the tool main body 5C. The tip of the shaft 768 abuts against the extensions 577, thereby restricting relative movement between the lower connecting portion 76C and the tool main body 5C in the left-right direction. The shaft 768 is movable within the recess 578 in any direction (e.g., front-rear direction, up-down direction) intersecting the axis of the shaft 768 (an axis extending substantially in the left-right direction) while elastically deforming the elastic member 88C. In addition, the lower connecting portion 76C is rotatable around the axis of the shaft portion 768.

[0110] As described above, in this embodiment, the tool body 5C and the outer housing 6C are also slidable relative to each other in the front-rear direction while being guided by the first guide portion 41 under the action of the elastic force of the spring 81A. This effectively prevents vibrations in the front-rear direction from being transmitted from the tool body 5C to the outer housing 6C. Furthermore, the tool body 5C and the outer housing 6C are also movable relative to each other in directions intersecting the drive axis DX (e.g., vertical and horizontal directions) under the action of the elastic force of the O-ring 83. This effectively prevents vibrations in the front-rear direction and in directions intersecting the drive axis DX from being transmitted from the tool body 5C to the outer housing 6C.

[0111] Furthermore, the upper connecting portion 73C and the outer housing 6C are slidable in the front-rear direction under the action of the elastic force of the spring 84C. Meanwhile, the lower connecting portion 76C and the tool main body 5C are movable relative to each other in any direction intersecting the axis of the shaft portion 768 (e.g., the front-rear direction, the up-down direction) and are rotatable about the axis under the action of the elastic force of the elastic member 88C. Therefore, while the lower connecting portion 76C is rotated relative to the tool main body 5C, the upper connecting portion 73C and the outer housing 6C can be moved relative to each other in the front-rear direction, which corresponds to the largest vibration, under the action of the elastic force of the spring 84C. Furthermore, vibrations in various directions of the tool main body 5C can be effectively suppressed from being transmitted to the handle 7C via the lower connecting portion 76C.

[0112] The correspondence between each component (feature) of the above embodiment and each component (feature) of the present disclosure or invention is shown below. However, each component of the embodiment is merely an example and does not limit each component of the present disclosure or invention.

[0113] Each of the hammer drills 1A, 1B, and 1C is an example of an "impact tool." The impact mechanism 30 is an example of a "drive mechanism." Each of the first guide portion 41 and the second guide portion 42 is an example of a "guide portion." The spring 81A is an example of a "first elastic member" or "mechanical spring." Each of the elastic member 82A and the O-ring 83 is an example of a "second elastic member" or "rubber or elastic synthetic resin." The spring 84A is an example of a "third elastic member." The elastic member 85A is an example of a "fourth elastic member." Each of the springs 81A, 84A, 86A, and 84C is an example of a "mechanical spring." Each of the elastic members 82A, 85A, 85B, 88B, and 88C is an example of a "rubber or elastic synthetic resin." The guide member 74 is an example of a "support member." Each of the upper connecting portions 73A, 73B, and 73C is an example of a "first end of the handle." Each of lower connecting portions 76A, 76B, and 76C is an example of a “second end of a handle.” Each of shaft portions 742, 633, and 576 is an example of a “shaft.”

[0114] It should be noted that the above-described embodiments are merely examples, and the impact tool according to the present disclosure is not limited to the illustrated hammer drills 1A, 1B, and 1C. For example, the following modifications can be made. Furthermore, at least one of these modifications can be adopted in combination with the hammer drills 1A, 1B, and 1C illustrated in the embodiments and at least one of the features described in each claim.

[0115] The impact tool according to the present disclosure may be an electric hammer (so-called scraper or demolition hammer) configured to perform only an impact action by linearly driving the bit. In this case, the rotation transmission mechanism 35 is omitted from the drive mechanism 3. Also, instead of the crank mechanism, the motion conversion mechanism may be a well-known mechanism configured to reciprocate a piston using a member (e.g., a swash bearing, a wobble plate / bearing) that oscillates in response to the rotation of a rotor.

[0116] A brushless DC motor may be used for the motor 2. The motor 2 may be driven by power supplied from a rechargeable battery. The arrangement of the motor 2 (rotation axis RX) relative to the drive axis DX may be changed as appropriate. For example, the rotation axis RX of the motor 2 may be diagonally intersecting the drive axis DX or may be parallel to the drive axis DX. The configuration of the tool bodies 5A, 5B, 5C may be changed as appropriate in accordance with or regardless of the change in the arrangement of the motor 2.

[0117] The outer housings 6A, 6B, 6C may be modified as appropriate as long as they cover at least a portion of the tool bodies 5A, 5B, 5C and are elastically connected to the tool bodies 5A, 5B, 5C so as to be slidable in the front-rear direction. The handles 7A, 7B, 7C may also be modified as appropriate as long as they are elastically connected to at least the outer housings 6A, 6B, 6C.

[0118] For example, the outer housings 6A, 6B, and 6C may entirely cover the tool bodies 5A, 5B, and 5C and be slidable relative to the tool bodies 5A, 5B, and 5C. In this modification, both the upper connecting portions 73A, 73B, and 73C and the lower connecting portions 76A, 76B, and 76C may be connected to the outer housings 6A, 6B, and 6C. Alternatively, in another modification, the outer housings 6A, 6B, and 6C may include upper and lower portions formed separately. The upper portion covers at least a portion of the drive mechanism accommodating portion 51 and is slidable relative to the drive mechanism accommodating portion 51 in the front-rear direction. The lower portion covers at least a portion of the motor accommodating portion 57 and is slidable relative to the motor accommodating portion 57 in the front-rear direction. In this modification, the upper connecting portions 73A, 73B, and 73C may be connected to the upper portions, and the lower connecting portions 76A, 76B, and 76C may be connected to the lower portions. Alternatively, only one of the two ends of the handles 7A, 7B, 7C may be connected to the outer housings 6A, 6B, 6C, and the other may be a free end.

[0119] The configuration, number, and / or arrangement of the spring 81A, which connects the tool main body 5A, 5B, 5C and the outer housing 6A, 6B, 6C in a direction substantially parallel to the drive axis DX (front-rear direction), may be modified as appropriate. For example, instead of the spring 81A, a mechanical spring of a type other than a compression coil spring (e.g., a torsion spring or a disc spring), or rubber or an elastic synthetic resin may be used. Similar modifications may also be made to the springs 84A, 86A, 84C, which connect the handles 7A, 7C and the outer housing 6A, 6C. Furthermore, the springs 84A and 86A may have different specifications, and the spring 84A may be installed with a larger initial load (also referred to as an installation load) than the spring 86A.

[0120] Similarly, the configuration, number, and / or arrangement of the elastic member 82A connecting the tool main body 5A, 5B, 5C and the outer housing 6A, 6B, 6C in the direction intersecting the drive axis DX may be modified as appropriate. For example, the elastic member 82A may be formed of rubber or other elastic synthetic resin (e.g., elastomer or synthetic resin foam other than urethane) instead of urethane foam. Instead of the elastic member 82A, for example, multiple elastic members may be interposed between the tool main body 5A, 5B, 5C and the outer housing 6A, 6B, 6C in the vertical and / or horizontal directions. Similar modifications may also be made to the elastic members 85A, 85B, 88B, 88C and the O-ring 83 connecting the handles 7A, 7B, 7C and the outer housing 6A, 6B, 6C.

[0121] The configuration for guiding the sliding movement between the tool main body 5A, 5B, 5C and the outer housing 6A, 6B, 6C in the direction substantially parallel to the drive axis DX (front-rear direction) is not limited to the first guide portion 41 and the second guide portion 42. For example, a guide portion similar to the third guide portion 43 or the seventh guide portion 47 may be provided on the tool main body 5A, 5B, 5C and the outer housing 6A, 6B, 6C. Furthermore, the covers 421, 442 are preferable in that they make the sliding movement smoother and suppress wear of the elastic members 82A, 85A, but may be omitted.

[0122] In view of the spirit of the present invention and the above-described embodiments, the following aspects are constructed, and at least one of the following aspects may be adopted in combination with the features of the embodiments and their variants, or at least one of the features described in each claim. [Aspect 1] The guide portion is a main body side guide portion provided on the tool main body; The housing further includes an outer guide portion that is provided on the outer housing and is slidable in the first direction relative to the first guide portion. The upper end surface 411 of the peripheral wall portion 571 of the motor accommodating portion 57 and the lower end surface 415 of the peripheral wall portion 61 of the outer housing 6A are examples of the "main body side guide portion" and the "outer side guide portion" in this embodiment. The cover 421 and the guide tube 425 are another example of the "main body side guide portion" and the "outer side guide portion" in this embodiment. [Aspect 2] the tool body includes a drive mechanism accommodating portion that extends in the first direction along the drive shaft and accommodates the drive mechanism, and a motor accommodating portion that is connected to the drive mechanism and extends in the second direction and accommodates the motor, the outer housing extends in the first direction along the drive shaft and covers the drive mechanism accommodating portion, the main body side guide portion is provided at one end of the peripheral wall portion of the motor accommodating portion in the second direction, The outer guide portion is provided at one end in the second direction of the peripheral wall portion of the outer housing. [Aspect 3] the second elastic member is an annular member made of rubber or an elastic synthetic resin and is disposed around the shaft extending in the first direction; One of the main body side guide portion and the outer side guide portion is a cover that covers an outer circumferential surface of the second elastic member, The other of the main body side guide portion and the outer side guide portion is a cylindrical portion that houses the cover so that the cover can slide in the first direction. [Aspect 4] The impact tool further includes a restricting portion configured to restrict movement of the handle relative to the outer housing in a third direction perpendicular to the first direction and the second direction. Each of the third guide portion 43, the fourth guide portion 44, and the seventh guide portion 47 is an example of the "restriction portion" of this embodiment. [Aspect 5] The restricting portion is configured to guide the relative sliding movement between the handle and the outer housing in the first direction and the second direction. [Explanation of symbols]

[0123] 1A, 1B, 1C: hammer drill, 2: motor, 21: stator, 23: rotor, 25: motor shaft, 251: bearing, 252: bearing, 27: fan, 29: power cord, 3: drive mechanism, 30: impact mechanism, 35: rotation transmission mechanism, 36: tool holder, 37: dynamic vibration absorber, 371: weight, 372: spring, 373: storage section, 374: spring receiver, 41: first guide section, 411: upper end surface, 415: lower end surface, 42: second guide section, 421: cover, 423: screw, 425: guide tube, 43: third guide part, 431: guide hole, 432: guide shaft, 433: screw hole, 435: screw, 44: fourth guide part, 441: front end part, 442: cover, 445: guide passage, 446: first part, 447: second part, 45: fifth guide part, 451: guide hole, 452: guide shaft, 454: screw hole, 455: screw, 46: sixth guide part, 461: front end part, 465: guide passage, 47: seventh guide part, 471: guide hole, 472: guide shaft, 473: screw hole, 475: screw, 5A, 5B, 5C: construction Tool body, 51: drive mechanism accommodating section, 511: rear wall section, 52: barrel section, 53: crank housing, 57: motor accommodating section, 571: peripheral wall section, 572: rear wall section, 573: spring receiver, 575: extension section, 576: shaft section, 577: extension section, 578: recess, 6A, 6B, 6C: outer housing, 61: peripheral wall section, 611: rear wall section, 612: spring receiver, 614: spring receiver, 617: spring receiver, 63: side section, 633: shaft section, 7A, 7B, 7C: handle, 71: grip section, 711: switch lever, 7 13: Switch, 73A, 73B, 73C: Upper connecting portion, 731: Spring holder, 733: Extension portion, 734: Recess, 737: Spring holder, 74: Guide member, 742: Shaft portion, 749: Screw, 76A, 76B, 76C: Lower connecting portion, 761: Spring holder, 765: Side portion, 766: Recess, 767: Side portion, 768: Shaft portion, 77: Guide member, 773: Screw, 81A, 84A, 84C, 86A: Spring, 82A: Elastic member, 83: O-ring, 85A, 85B, 88B, 88C: Elastic member, 91: Tip tool

Claims

1. A motor; a drive mechanism operably connected to the motor and configured to linearly drive at least the tool bit along a drive shaft in response to driving of the motor; a tool body that houses the motor and the drive mechanism; an outer housing elastically coupled to the tool body so as to cover at least a portion of the tool body and slidable relative to the tool body in a first direction substantially parallel to the drive shaft; a guide portion configured to guide sliding of the outer housing relative to the tool body; An impact tool comprising a handle including a grip portion extending in a second direction intersecting the first direction, the handle being elastically connected to at least the outer housing and movable relative to the outer housing in the first direction and at least one direction intersecting the first direction.

2. The impact tool according to claim 1, The impact tool, wherein the outer housing is also movable relative to the tool body in at least one direction intersecting the first direction.

3. The impact tool according to claim 2, An impact tool characterized in that the tool body and the outer housing are connected by a first elastic member so as to be able to move relative to each other in the first direction, and are connected by a second elastic member separate from the first elastic member so as to be able to move relative to each other in at least one direction intersecting the first direction.

4. The impact tool according to claim 3, the first elastic member is a mechanical spring, The impact tool, wherein the second elastic member is made of rubber or synthetic resin having elasticity.

5. The impact tool according to any one of claims 1 to 4, An impact tool characterized in that the outer housing and the handle are connected by a third elastic member so as to be able to move relative to each other in the first direction, and are connected by a fourth elastic member separate from the third elastic member so as to be able to move relative to each other in at least one direction intersecting the first direction.

6. The impact tool according to claim 5, the third elastic member is a mechanical spring, The impact tool, wherein the fourth elastic member is made of rubber or synthetic resin having elasticity.

7. The impact tool according to claim 5, the outer housing and the handle are connected by the fourth elastic member so as to be relatively movable in the second direction; the fourth elastic member is supported by a support member, The impact tool, wherein the support member is configured to restrict movement of the handle relative to the outer housing in a third direction perpendicular to the first direction and the second direction.

8. The impact tool according to any one of claims 1 to 4, the handle includes a first end connected to an end of the grip portion closer to the drive shaft and a second end connected to an end of the grip portion farther from the drive shaft in the second direction; each of the first end and the second end is elastically coupled to the tool body or the outer housing so as to be movable in the first direction; At least one of the first end and the second end is elastically connected to the outer housing.

9. The impact tool according to claim 8, the first end is resiliently connected to the outer housing; The impact tool, wherein the second end is elastically connected to the tool body.

10. The impact tool according to claim 8, the first end and the second end are elastically connected to the tool body or the outer housing by a mechanical spring, An impact tool, characterized in that the initial load of the mechanical spring at the first end is greater than the initial load of the mechanical spring at the second end.

11. The impact tool according to claim 8, an impact tool, characterized in that each of the first end and the second end is elastically connected to the tool body or the outer housing by rubber or an elastic synthetic resin so as to be movable in the first direction, the second direction, and a third direction perpendicular to the first direction and the second direction.

12. The impact tool according to claim 11, An impact tool characterized in that the rubber or elastic synthetic resin is annular and arranged around a shaft extending in a third direction perpendicular to the first direction and the second direction.

13. The impact tool according to claim 8, the first end is resiliently connected to the tool body or the outer housing by a mechanical spring; The impact tool, wherein the second end is rotatable relative to the tool body or the outer housing about an axis extending in a third direction perpendicular to the first direction and the second direction.

14. A motor; a drive mechanism operably connected to the motor and configured to linearly drive at least the tool bit along a drive shaft in response to driving of the motor; a tool body that houses the motor and the drive mechanism; an outer housing elastically coupled to the tool body so as to cover at least a portion of the tool body and slidable relative to the tool body in a first direction substantially parallel to the drive shaft; a guide portion configured to guide sliding of the outer housing relative to the tool body; A handle including a grip portion extending in a second direction intersecting the first direction, a first end portion connected to one end of the grip portion, and a second end portion connected to the other end of the grip portion, each of the first end and the second end of the handle is resiliently coupled to the tool body or the outer housing so as to be movable relative to the tool body or the outer housing in at least the first direction; At least one of the first end and the second end is elastically connected to the outer housing.

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