Work equipment

Abstract

Suppresses a decline in work efficiency. [Solution] In the hammer 1, the gear mechanism 70 includes a crank gear 74 and a coupling 72 that are connected so as to be rotatable relative to each other about an axis AL, and a damper spring 80 interposed between the crank gear 74 and the coupling 72. When the motor 40 is driven, the coupling 72 rotates relative to the crank gear 74, causing the damper spring 80 to elastically deform. The crank gear 74 has a gear body side support hole 76C and a cover side support hole 78C that support the damper spring 80 in the rotational direction, and the coupling 72 has a coupling side support hole 72B that supports the damper spring 80 in the rotational direction, with the gear body side support hole 76C and the cover side support hole 78C facing the coupling side support hole 72B in the vertical direction. Therefore, the damper spring 80 can suppress vibrations of the drive force transmission mechanism 42, thereby suppressing a decrease in the workability of the hammer 1.

Description

Technical Field

[0006] , ,

[0001] The present invention relates to a working machine.

Background Art

[0002] In the hammer (working machine) described in Patent Document 1 below, an impact force is applied to a tip tool to perform a breaking process or the like on a workpiece. Specifically, a piston is provided so as to be reciprocally movable within a cylinder, and a striker is provided on the front side of the piston within the cylinder. As the piston reciprocates, the pressure within the pressure chamber in the cylinder changes, and an impact force is applied to the tip tool by the striker.

Prior Art Documents

[0007] One or more embodiments of the present invention are a work machine in which the drive-side support and the driven-side support support support the elastic part from both sides in the direction of rotation.

[0008] One or more embodiments of the present invention are a work machine in which a plurality of the drive-side support members are provided on the drive-side rotating part and arranged in the direction of rotation, and a plurality of the driven-side support members are provided on the driven-side rotating part and arranged in the direction of rotation.

[0009] One or more embodiments of the present invention are a work machine in which the drive-side support portion is an elongated hole extending in the rotational tangential direction of the drive-side rotating portion, the driven-side support portion is an elongated hole extending in the rotational tangential direction of the drive-side rotating portion, and the elastic portion is a compression coil spring disposed inside the drive-side support portion and the driven-side support portion and extending in the longitudinal direction of the drive-side support portion and the driven-side support portion.

[0010] One or more embodiments of the present invention are work machines in which the drive-side rotating part has a recess that is open to one side in the predetermined direction, and at least a part of the driven-side rotating part is disposed within the recess.

[0011] One or more embodiments of the present invention include a drive-side rotating part comprising a bottomed cylindrical main body having the recess, and a cover assembled integrally and rotatably to the main body, which closes the recess and sandwiches the driven-side rotating part together with the main body in the predetermined direction, and the drive-side support part is provided on the main body and the cover, respectively, and the drive-side support part provided on the main body and the drive-side support part provided on the cover sandwich the driven-side support part in the predetermined direction.

[0012] One or more embodiments of the present invention are working machines in which a drive gear that rotates in response to the driving force of the drive unit is provided on the radially outer side of the main body, and external teeth that mesh with the drive gear are provided on the outer circumference of the main body.

[0013] One or more embodiments of the present invention are working machines in which the driven rotating part has a shaft portion with the axis as its axis, the axial ends of the shaft portion protrude from the driving rotating part on both sides in the predetermined direction, retaining rings are provided at the axial ends of the shaft portion, and the relative movement of the driving rotating part with respect to the driven rotating part in the predetermined direction is restricted by the retaining rings.

[0014] One or more embodiments of the present invention are working machines comprising: a crank mechanism connected to the driven rotating part, the crank mechanism comprising: a crankshaft extending along the axis and connected to the driven rotating part so as to be rotatable integrally; an eccentric shaft configured to be rotatable integrally with the crankshaft and provided at an eccentric position with respect to the crankshaft; and a piston connected to the eccentric shaft via a piston rod and moving back and forth in an orthogonal direction perpendicular to the predetermined direction by the rotation of the crankshaft.

[0015] One or more embodiments of the present invention are work machines comprising: a drive unit; an end tool that operates by receiving the driving force of the drive unit; a drive force transmission unit that transmits the driving force of the drive unit to the end tool; a case that houses the drive unit and the drive force transmission unit; a housing that supports the case so as to be movable relative to it and has a handle for gripping by an operator; an outer vibration reduction unit provided between the case and the housing to suppress the transmission of vibrations generated when the drive force transmission unit is operating from the case to the handle; and an inner vibration reduction unit housed inside the case to suppress the transmission of vibrations generated when the drive force transmission unit is operating to the case.

[0016] One or more embodiments of the present invention include a drive force transmission unit comprising a drive-side rotating unit that rotates about an axis extending in a predetermined direction upon receiving the driving force of the drive unit, and a driven-side rotating unit that transmits the driving force of the drive unit to the tip tool by rotating about the axis upon receiving the rotational force of the drive-side rotating unit, wherein the internal vibration reduction unit is a work machine interposed between the drive-side rotating unit and the driven-side rotating unit.

[0017] One or more embodiments of the present invention are work machines in which the internal vibration reducing section is configured to be elastically deformable and is supported by the drive-side rotating section and the driven-side rotating section, and the internal vibration reducing section is elastically deformed when the driven-side rotating section rotates relative to the drive-side rotating section.

[0018] One or more embodiments of the present invention are work machines in which the external vibration reduction unit is configured to be elastically deformable and is supported by the case and the housing, and the external vibration reduction unit is elastically deformed when the case moves relative to the housing. [Effects of the Invention]

[0019] According to one or more embodiments of the present invention, it is possible to improve workability while suppressing a decrease in workability. [Brief explanation of the drawing]

[0020] [Figure 1] It is a cross-sectional view seen from the left showing the inside of the hammer according to this embodiment. [Figure 2] It is a cross-sectional view seen from the rear showing the inside of the rear part of the hammer shown in FIG. 1 (a cross-sectional view taken along line 2-2 of FIG. 1). [Figure 3] It is a cross-sectional view seen from the front showing the inside of the rear part of the hammer shown in FIG. 1 (a cross-sectional view taken along line 3-3 of FIG. 1). [Figure 4] (A) is a plan view seen from above showing the connection state of the gear mechanism to the crankshaft shown in FIG. 1, and (B) is a side view seen from the rear of the crankshaft and the gear mechanism of (A). [Figure 5] It is a cross-sectional view seen from the right showing the connection state of the gear mechanism to the crankshaft shown in FIG. 4(B) (a cross-sectional view taken along line 5-5 of FIG. 4(B)). [Figure 6] It is a cross-sectional view seen from below showing the connection state of the gear mechanism to the crankshaft shown in FIG. 4(B) (a cross-sectional view taken along line 6-6 of FIG. 4(B)). [Figure 7] It is an exploded perspective view of the gear mechanism shown in FIG. 4(A).

Mode for Carrying Out the Invention

[0021] Hereinafter, the hammer 1 as a working machine according to this embodiment will be described with reference to the drawings. The hammer 1 is a power tool for performing a breaking process or the like on a workpiece. The arrows UP, FR, and LH appropriately shown in the drawings indicate the upper side, the front side, and the left side of the hammer 1. In the following description, when the up-down, front-back, and left-right directions are used for explanation, unless otherwise specified, they indicate the up-down direction, the front-back direction, and the left-right direction of the hammer 1. And the up-down direction corresponds to the predetermined direction of the present invention, and the front-back direction corresponds to the orthogonal direction of the present invention. In the drawings, for the sake of convenience, the hatching is appropriately omitted.

[0022] As shown in Figure 1, the hammer 1 is composed of a housing 10, a striking force application mechanism 30 for applying striking force to the tip tool T (broadly speaking, an element that can be understood as a drive mechanism), and a support mechanism 60.

[0023] (Regarding Housing 10) The housing 10 is formed in a hollow shape and constitutes the outer casing of the hammer 1. The housing 10 is composed of a plurality of housing members, and the housing 10 is formed by assembling these housing members together. The housing 10 as a whole extends in the front-rear direction and has a rear housing portion 12 that constitutes the rear of the housing 10 and a front housing portion 14 that constitutes the front of the housing 10.

[0024] The rear housing portion 12 is formed in a substantially hollow, flattened box shape with the left-right direction being the thickness direction. A handle 12A extending in the vertical direction is provided at the rear end of the rear housing portion 12. Both ends of the handle 12A in the vertical direction are bent forward and connected to the rear housing portion 12. A battery mounting portion 12B is provided in the rear housing portion 12 below the handle 12A, and a battery 20 is mounted in the battery mounting portion 12B from the rear.

[0025] A trigger 22 is provided on the upper part of the handle 12A, and the trigger 22 protrudes forward from the handle 12A so that it can be pulled backward. A switch (not shown) is provided inside the handle 12A, and the switch is turned on when the operator pulls the trigger 22. The switch is electrically connected to a controller 24 located in the rear housing 12, and outputs an output signal to the controller 24 according to the operating state of the trigger 22.

[0026] The front housing portion 14 is formed in a substantially cylindrical shape with its axial direction in the front-rear direction and extends forward from the upper part of the rear housing portion 12. A metal support cylinder portion 14A is provided at the rear end of the front housing portion 14. The support cylinder portion 14A is arranged coaxially with the front housing portion 14, and the inner circumferential surface of the support cylinder portion 14A protrudes slightly radially inward relative to the inner circumferential surface of the front housing portion 14.

[0027] (Regarding the impact force application mechanism 30) The impact force application mechanism 30 is composed of an inner case 32 as a case, a motor 40 as a drive unit, and a drive force transmission mechanism 42 as a drive force transmission unit.

[0028] (Regarding Inner Case 32) The inner case 32 is housed within the housing 10 and is supported by a support mechanism 60, described later, so as to be movable relative to the housing 10 in the front-rear direction. The inner case 32 is composed of a motor case 34 which constitutes the rear part of the inner case 32 and a cylinder case 36 which constitutes the front part of the inner case 32.

[0029] The motor case 34 is formed in a substantially hollow box shape that is open to the front and is housed within the rear housing portion 12. The cylinder case 36 is formed in a substantially cylindrical shape with the front-to-rear direction as its axial direction. The rear end of the cylinder case 36 is connected to the front end of the motor case 34, so that the inside of the cylinder case 36 and the inside of the motor case 34 are in communication. The cylinder case 36 is arranged coaxially with the front housing portion 14 and is housed within the front housing portion 14. An enlarged diameter portion 36A is formed on the outer circumference of the cylinder case 36, extending radially outward. The enlarged diameter portion 36A is positioned adjacent to the radially inward side of the support cylinder portion 14A of the housing 10 and is supported by the support cylinder portion 14A so as to be movable in the front-to-rear direction. In other words, the impact force application mechanism 30 is connected to the housing 10 so as to be movable in the front-to-rear direction.

[0030] A retainer sleeve 38 is provided on the front side of the cylinder case 36. The retainer sleeve 38 is formed in a substantially cylindrical shape with its axial direction in the front-rear direction and is positioned coaxially with the cylinder case 36. The rear end of the retainer sleeve 38 is fitted into the front end of the cylinder case 36, and the retainer sleeve 38 is connected to the cylinder case 36 so as to be able to move integrally with it. The retainer sleeve 38 protrudes forward from the front housing portion 14. The tip tool T is attached to the front of the retainer sleeve 38 and protrudes forward from the retainer sleeve 38.

[0031] (Regarding motor 40) The motor 40 is housed in the rear of the motor case 34. The motor 40 has a rotating shaft 40A whose axial direction is vertical. The rotating shaft 40A is rotatably connected to the motor case 34. A pinion gear 40B is formed at the upper end of the rotating shaft 40A. The motor 40 is electrically connected to the controller 24 and is driven by the controller 24.

[0032] (Regarding the power transmission mechanism 42) The power transmission mechanism 42 is housed within the inner case 32. The power transmission mechanism 42 consists of a transmission gear 44 as a drive gear, a gear mechanism 70, and a crank mechanism 46. The transmission gear 44 and the crank mechanism 46 will be described below, and the gear mechanism 70 will be described later.

[0033] The transmission gear 44 is positioned in front of the pinion gear 40B of the motor 40 and is rotatably connected to the motor case 34 with its vertical direction as the axial direction. A gear portion is formed on the outer circumference of the transmission gear 44, and this gear portion meshes with the pinion gear 40B of the motor 40.

[0034] The crank mechanism 46 comprises a crankshaft 48, a cylinder 50, a piston 52, a striking element 56, and an intermediate element 58. The crankshaft 48 is positioned in front of the transmission gear 44, with its vertical direction as its axial direction. The upper end of the crankshaft 48 is rotatably supported by a bearing 86, and the axial middle portion of the crankshaft 48 is rotatably supported by a bearing 88. The bearings 86 and 88 are held in the motor case 34. The rotational force of the motor 40 is transmitted to the crankshaft 48 by a gear mechanism 70, which will be described later, causing the crankshaft 48 to rotate around its axis AL.

[0035] A plate portion 48A is provided at the lower end of the crankshaft 48, and the plate portion 48A is formed in a substantially disc shape with the vertical direction being the thickness direction. An eccentric shaft 48B is provided on the plate portion 48A. The eccentric shaft 48B is formed in a substantially cylindrical shape with the vertical direction being the axial direction, and protrudes downward from the plate portion 48A. The eccentric shaft 48B is positioned eccentrically with respect to the axis AL of the crankshaft 48.

[0036] The cylinder 50 is formed in a cylindrical shape with its axial direction in the front-rear direction. The cylinder 50 is housed within the cylinder case 36 and is positioned coaxially with the cylinder case 36. The cylinder 50 is positioned in front of the crankshaft 48 and is fixed to the inner case 32.

[0037] The piston 52 is formed in a substantially cylindrical shape with its axial direction in the front-rear direction and is inserted into the rear of the cylinder 50 so as to be movable relative to it in the front-rear direction. The piston 52 is provided with a piston rod 54. The piston rod 54 extends in the front-rear direction, and its front end is rotatably connected to the piston 52 with its axial direction in the up-down direction, while its rear end is rotatably connected to an eccentric shaft 48B. As a result, when the motor 40 rotates, the piston 52 reciprocates in the front-rear direction by the eccentric shaft 48B, which rotates eccentrically around its axis AL.

[0038] The striking element 56 is formed in a substantially cylindrical shape with its axial direction in the front-rear direction. The striking element 56 is inserted into the cylinder 50 so as to be movable relative to the piston 52, and is positioned spaced apart in front of the piston 52. The space between the piston 52 and the striking element 56 within the cylinder 50 is an air chamber 50A. The intermediate element 58 is formed in a substantially cylindrical shape with its axial direction in the front-rear direction and is inserted into the retainer sleeve 38 so as to be movable relative to the piston 56. The intermediate element 58 is positioned adjacent to the front of the striking element 56. As a result, when the piston 52 moves forward, the pressure in the air chamber 50A increases, causing the striking element 56 and the intermediate element 58 to move forward, and an impact force along the front-rear direction is applied to the tip tool T.

[0039] (Regarding the support mechanism 60) As shown in Figures 1 to 3, the support mechanism 60 is composed of the support cylinder portion 14A of the housing 10 described above, a spring holder 62, an upper vibration damping spring 64 as an outer vibration reduction part, a pair of left and right lower vibration damping springs 66, and a vibration damping plate spring 68.

[0040] The spring holder 62 is housed within the rear end of the rear housing portion 12 and is positioned behind the lower end of the motor case 34. The spring holder 62 is formed in a substantially elongated shape that extends in the left-right direction and is fixed to the rear housing portion 12.

[0041] The upper vibration-damping spring 64 is a compression coil spring extending in the front-rear direction. The upper vibration-damping spring 64 is housed within the rear end of the rear housing portion 12 and is positioned on the rear side of the motor case 34. Specifically, the front end of the upper vibration-damping spring 64 is supported in the middle of the left-right direction at the upper end of the motor case 34, and the rear end of the upper vibration-damping spring 64 is supported by the rear wall of the rear housing portion 12, so that the upper vibration-damping spring 64 biases the inner case 32 forward. The inner case 32 abuts against the rear housing portion 12 at a position not shown, and its forward movement is restricted, thereby holding the inner case 32 in its initial position (the position shown in Figure 1).

[0042] The pair of lower vibration-damping springs 66 are compression coil springs extending in the front-rear direction. The lower vibration-damping springs 66 are housed within the rear end of the rear housing portion 12 and are positioned between the motor case 34 and the spring holder 62. The front end of each lower vibration-damping spring 66 is supported by the left-right outer end of the lower end of the motor case 34, and the rear end of each lower vibration-damping spring 66 is supported by the left-right outer end of the spring holder 62, causing the lower vibration-damping springs 66 to bias the inner case 32 forward.

[0043] The vibration-damping leaf spring 68 is a leaf spring with its thickness oriented in the front-rear direction, and is formed in a roughly inverted U-shape that opens downwards when viewed from the front-rear direction. The vibration-damping leaf spring 68 is housed within the rear end of the rear housing portion 12 and is positioned on the rear side of the motor case 34. The left and right ends of the upper end of the vibration-damping leaf spring 68 are fixed to the upper end of the motor case 34, and the lower end of the vibration-damping leaf spring 68 is fixed to the spring holder 62.

[0044] Furthermore, during the fracture treatment of the hammer 1, the tip tool T is pressed against the workpiece located at the front, causing the inner case 32 to displace to the rear against the biasing force of the upper vibration-damping spring 64, the lower vibration-damping spring 66, and the vibration-damping leaf spring 68. In other words, the inner case 32 is supported in a floating state relative to the housing 10 while being biased forward by the upper vibration-damping spring 64, the lower vibration-damping spring 66, and the vibration-damping leaf spring 68. When impact force is applied to the tip tool T by the impact force application mechanism 30, the upper vibration-damping spring 64, the lower vibration-damping spring 66, and the vibration-damping leaf spring 68 elastically deform, absorbing the vibrations generated during impact and suppressing the transmission of these vibrations to the handle 12A.

[0045] (Regarding gear mechanism 70) As shown in Figures 1, 4 to 7, the gear mechanism 70 is composed of a coupling 72 as a driven rotating part, a crank gear 74 as a driving rotating part, and a plurality (four in this embodiment) of damper springs 80 as an elastic part and an internal vibration reducing part.

[0046] The coupling 72 is formed in a substantially disc shape with the vertical direction being the thickness direction. A fixed shaft 72A is provided in the center of the coupling 72 as the shaft portion. The fixed shaft 72A is formed in a substantially cylindrical shape with the vertical direction being the axial direction, and the inside of the fixed shaft 72A penetrates in the vertical direction. Both axial ends of the fixed shaft 72A protrude outward from the coupling 72 in the vertical direction. The upper part of the crankshaft 48 is press-fitted into the fixed shaft 72A, and the coupling 72 is connected to the crankshaft 48 so as to be able to rotate integrally with it. In other words, the axis of the fixed shaft 72A coincides with the axis AL.

[0047] The coupling 72 has multiple (four in this embodiment) coupling-side support holes 72B formed through it, which serve as driven-side support parts. The multiple coupling-side support holes 72B are arranged in a line with predetermined intervals in the circumferential direction (rotational direction) of the coupling 72. Specifically, one coupling-side support hole 72B is located on the right side of the coupling 72, and the multiple couplings 72 are arranged at 90-degree intervals in the circumferential direction of the coupling 72. The coupling-side support holes 72B are formed in the shape of rectangular elongated holes in a plan view. Specifically, a pair of coupling-side support holes 72B located outward in the left-right direction relative to the axis AL extends in the front-rear direction, and a pair of coupling-side support holes 72B located outward in the front-rear direction relative to the axis AL extends in the left-right direction. That is, the coupling-side support holes 72B extend along the rotational tangential direction of the coupling 72 at the center of the coupling-side support hole 72B.

[0048] The crank gear 74 is composed of a gear body 76 as the main body and a gear cover 78 as a cover. The gear body 76 is formed in a relatively shallow bottomed cylindrical shape that is open to the upper side (one side in the vertical direction). That is, the gear body 76 has a recess 76A that is open to the upper side. A circular body-side insertion hole 76B is formed through the center of the bottom wall of the gear body 76. The lower end of the fixed shaft 72A of the coupling 72 is inserted into the body-side insertion hole 76B from above, and the gear body 76 is rotatably supported (connected) to the fixed shaft 72A. That is, the axis of the gear body 76 coincides with the axis AL. When the gear body 76 is connected to the coupling 72, the coupling 72 is positioned in the recess 76A of the gear body 76, and the lower end of the fixed shaft 72A protrudes downward from the gear body 76. A retaining ring 82 is provided on the outer circumference of the lower end of the fixed shaft 72A, and the retaining ring 82 is positioned adjacent to the lower side of the gear body 76. This restricts the relative downward movement of the gear body 76 with respect to the coupling 72.

[0049] Multiple (four in this embodiment) gear body-side support holes 76C, which serve as drive-side support parts, are formed through the bottom wall of the gear body 76. The gear body-side support holes 76C are arranged in a line with predetermined intervals in the circumferential direction (rotational direction) of the gear body 76, and are positioned opposite the coupling-side support holes 72B of the coupling 72 in the vertical direction. The gear body-side support holes 76C are formed in a rectangular elongated shape, similar to the coupling-side support holes 72B. That is, the gear body-side support holes 76C extend along the rotational tangential direction of the gear body 76 at the center of the gear body-side support holes 76C. The longitudinal length of the gear body-side support holes 76C is the same as the longitudinal length of the coupling-side support holes 72B. Furthermore, a portion of the damper spring 80, which will be described later, is positioned inside the gear body side support hole 76C, and a portion of the inner circumferential surface of the gear body side support hole 76C is cut out to avoid interference with the damper spring 80.

[0050] Multiple (four in this embodiment) fitting portions 76D are provided on the inner circumference of the side wall of the gear body 76. When viewed from above, the fitting portions 76D are formed in the shape of a concave block that opens radially inward of the gear body 76. That is, the fitting portions 76D have fitting grooves 76E that open radially inward of the gear body 76. The fitting portions 76D are arranged between adjacent gear body-side support holes 76C in the circumferential direction of the gear body 76. In other words, in the gear body 76, the fitting portions 76D and gear body-side support holes 76C are arranged alternately in the circumferential direction.

[0051] The outer circumference of the side wall of the gear body 76 is provided with a gear portion 76F, which serves as an external gear. The gear portion 76F is composed of multiple gear teeth and meshes with the gear portion of the transmission gear 44.

[0052] The gear cover 78 is formed in a substantially disc shape with the vertical direction being the thickness direction. A circular cover-side insertion hole 78A is formed through the center of the gear cover 78. The upper end of the fixed shaft 72A of the coupling 72 is inserted into the cover-side insertion hole 78A from below, and the gear cover 78 is rotatably supported (connected) to the fixed shaft 72A. In other words, the crank gear 74 is rotatably connected to the coupling 72. When the gear cover 78 is connected to the coupling 72, the gear cover 78 is positioned within the opening of the recess 76A in the gear body 76, closing the recess 76A. The upper end of the fixed shaft 72A protrudes upward from the gear cover 78. A retaining ring 84 is provided on the outer circumference of the upper end of the fixed shaft 72A, and the retaining ring 84 is positioned adjacent to the upper side of the gear cover 78. Furthermore, the gear cover 78 is sandwiched vertically between the retaining ring 84 and the fitting portion 76D of the gear body 76, thereby restricting the vertical movement of the gear cover 78. In addition, the coupling 72 is sandwiched vertically between the gear cover 78 and the gear body 76.

[0053] A fitting column 78B is provided on the outer circumference of the gear cover 78 at a position corresponding to the fitting groove 76E of the gear body 76. The fitting column 78B is formed in a substantially rectangular column shape that extends in the vertical direction and extends downward from the gear cover 78. The fitting column 78B is fitted into the fitting groove 76E, and the fitting column 78B and the fitting portion 76D are engaged in the rotational direction of the crank gear 74. As a result, the gear cover 78 is connected to the gear body 76 so that it can rotate integrally with it.

[0054] Multiple (four in this embodiment) cover-side support holes 78C are formed through the gear cover 78 to serve as drive-side support parts. The cover-side support holes 78C are arranged in a line with predetermined intervals in the circumferential direction (rotational direction) of the gear cover 78, and are positioned opposite the coupling-side support holes 72B of the coupling 72 in the vertical direction. As a result, the coupling-side support holes 72B, the coupling-side support holes 72B of the coupling 72, and the gear body-side support holes 76C of the gear body 76 are arranged in a line in the vertical direction. The cover-side support holes 78C are formed in a rectangular elongated shape in plan view, similar to the coupling-side support holes 72B. That is, the cover-side support holes 78C extend along the rotational tangential direction of the gear cover 78 at the center of the cover-side support hole 78C. The longitudinal length of the cover-side support holes 78C is the same as the longitudinal length of the coupling-side support holes 72B. Furthermore, a portion of the damper spring 80, which will be described later, is positioned inside the cover-side support hole 78C, and a portion of the inner circumferential surface of the cover-side support hole 78C is cut out to avoid interference with the damper spring 80.

[0055] The damper spring 80 is a compression coil spring. The damper spring 80 is positioned in a compressed state inside the coupling-side support hole 72B of the coupling 72, the gear body-side support hole 76C of the crank gear 74, and the cover-side support hole 78C. Specifically, one end of the damper spring 80 is supported by one longitudinal end of the coupling-side support hole 72B, the gear body-side support hole 76C, and the cover-side support hole 78C, and the other end of the damper spring 80 is supported by the other longitudinal end of the coupling-side support hole 72B, the gear body-side support hole 76C, and the cover-side support hole 78C. In other words, the damper spring 80 is interposed between the crank gear 74 and the coupling 72, and the damper spring 80 connects the crank gear 74 and the coupling 72 so that they can rotate as a single unit. Furthermore, when a high relative rotational force is applied between the crank gear 74 and the coupling 72, the damper spring 80 elastically deforms, causing the crank gear 74 and the coupling 72 to rotate relative to each other. Specifically, when the drive force transmission mechanism 42 is in operation and the piston 52 moves forward, the spring load of the damper spring 80 is set so that the coupling 72 rotates relative to the crank gear 74.

[0056] As described above, since both ends of the damper spring 80 are supported by the coupling-side support hole 72B of the coupling 72, the gear body-side support hole 76C of the crank gear 74, and the cover-side support hole 78C, when the damper spring 80 is supported, the outer circumference of the damper spring 80 protrudes outward in the vertical direction compared to the crank gear 74.

[0057] (Effects and Benefits) Next, the operation and effects of this embodiment will be described.

[0058] When performing fracture treatment or other processes on a workpiece using the hammer 1 configured as described above, the operator grips the handle 12A and presses the tip tool T against the workpiece located in front. This causes the inner case 32 to be displaced to the rear against the biasing forces of the upper vibration damping spring 64, the lower vibration damping spring 66, and the vibration damping leaf spring 68. That is, the enlarged diameter portion 36A of the cylinder case 36 slides on the inner circumferential surface of the support cylinder portion 14A of the housing 10, causing the inner case 32 to move relative to the housing 10 to the rear. As a result, the inner case 32 is biased forward by the upper vibration damping spring 64, the lower vibration damping spring 66, and the vibration damping leaf spring 68, while floating relative to the housing 10. In this state, when the trigger 22 is pulled, the driving force of the motor 40 activates the drive force transmission mechanism 42, and a striking force along the front-rear direction is applied to the tip tool T. Specifically, the piston 52 reciprocates in the front-rear direction, causing a pressure change within the air chamber 50A. In response to this pressure change, the impactor 56 and the intermediate element 58 reciprocate in the front-rear direction, thereby applying an impact force along the front-rear direction to the tip tool T. Therefore, vibrations are generated when the drive force transmission mechanism 42 is in operation, and if these vibrations are transmitted to the handle 12A held by the operator, the workability of the hammer 1 may decrease.

[0059] In the hammer 1, the drive force transmission mechanism 42 that transmits the driving force of the motor 40 to the tip tool T has a gear mechanism 70. The gear mechanism 70 has a crank gear 74 and a coupling 72 that are connected so as to be rotatable relative to each other about an axis AL, and a damper spring 80 interposed between the crank gear 74 and the coupling 72. When the motor 40 is driven, the coupling 72 rotates relative to the crank gear 74, and the damper spring 80 undergoes elastic deformation. The crank gear 74 has a gear body side support hole 76C and a cover side support hole 78C that support the damper spring 80 in the rotational direction, and the coupling 72 has a coupling side support hole 72B that supports the damper spring 80 in the rotational direction, with the gear body side support hole 76C and the cover side support hole 78C positioned vertically opposite the coupling side support hole 72B. As described above, the damper spring 80 suppresses vibrations during the operation of the drive force transmission mechanism 42, thereby preventing a decrease in workability in the hammer 1. This point will be explained in detail below.

[0060] In other words, when the drive force transmission mechanism 42 is operating, the piston 52 moves forward within the cylinder 50, increasing the pressure in the air chamber 50A, and when the direction of movement of the piston 52 switches to the rearward side, the pressure in the air chamber 50A decreases. Therefore, when the piston 52 moves back and forth, a reaction force acts on the piston 52 to the rearward side as the pressure in the air chamber 50A increases, and this reaction force is maximum when the piston 52 is displaced furthest forward. Consequently, when the motor 40 is driven, fluctuations in the reaction force acting on the piston 52 cause rotational irregularities in the gear mechanism 70, resulting in vibration in the drive force transmission mechanism 42.

[0061] Here, a damper spring 80 is interposed between the crank gear 74 and the coupling 72. Therefore, when the piston 52 moves forward, the damper spring 80 is compressed and deformed, causing the crank gear 74 and the coupling 72 to rotate relative to each other, thereby mitigating the reaction force transmitted from the piston 52 to the crank gear 74. This suppresses rotational irregularities of the crank gear 74 when the motor 40 is driven, and reduces vibrations during the operation of the drive force transmission mechanism 42.

[0062] Furthermore, the gear body-side support hole 76C and cover-side support hole 78C of the crank gear 74 that supports the damper spring 80 are positioned vertically opposite to the coupling-side support hole 72B of the coupling 72. That is, the gear body-side support hole 76C and cover-side support hole 78C and the coupling-side support hole 72B are positioned vertically side by side. This allows both ends of the damper spring 80 to be supported by the crank gear 74 and the coupling 72. Therefore, compared to a configuration in which, for example, one end of the damper spring 80 is supported only by the crank gear 74 and the other end is supported only by the coupling 72, the installation space for the damper spring 80 in the gear mechanism 70 can be increased. In other words, a larger damper spring 80 can be installed in the gear mechanism 70. This allows the spring load of the damper spring 80 to be set to a load that can effectively absorb the reaction force from the piston 52. As described above, the hammer 1 of this embodiment can suppress vibrations during operation of the drive force transmission mechanism 42. Therefore, the workability of the hammer 1 can be improved.

[0063] Furthermore, in the gear mechanism 70, the gear body side support hole 76C and cover side support hole 78C of the crank gear 74 and the coupling side support hole 72B of the coupling 72 support the damper spring 80 from both sides in the rotational direction of the gear mechanism 70. As a result, even when the coupling 72 rotates relative to the crank gear 74 in the opposite direction due to the reaction force from the piston 52 exceeds its maximum value, the damper spring 80 can be compressed and deformed. This further suppresses vibrations that occur when the drive force transmission mechanism 42 is in operation.

[0064] Furthermore, the crank gear 74 is provided with four gear body-side support holes 76C and cover-side support holes 78C, and the coupling 72 is provided with four coupling-side support holes 72B, with the gear body-side support holes 76C, cover-side support holes 78C, and coupling-side support holes 72B all arranged in the rotational direction of the gear mechanism 70. Damper springs 80 are provided inside each of the gear body-side support holes 76C, cover-side support holes 78C, and coupling-side support holes 72B. As a result, the reaction force from the piston 52 can be received by the multiple damper springs 80. Therefore, vibrations during the operation of the drive force transmission mechanism 42 can be further reduced.

[0065] Furthermore, the damper spring 80 is a compression coil spring, and the gear body side support hole 76C, the cover side support hole 78C, and the coupling side support hole 72B are rectangular elongated holes whose longitudinal direction is the rotational tangential direction of the gear mechanism 70 at their respective centers. This allows the damper spring 80 to be interposed between the crank gear 74 and the coupling 72 with a simple configuration, thereby transmitting the rotational force of the crank gear 74 to the coupling 72 via the damper spring 80.

[0066] Furthermore, the crank gear 74 is composed of a gear body 76 having an upwardly opening recess 76A, and a gear cover 78 that closes the opening of the recess 76A. The coupling 72 is positioned within the recess 76A of the gear body 76. This contributes to reducing the size of the gear mechanism 70 in the vertical direction.

[0067] Furthermore, in the gear mechanism 70, the coupling 72 is sandwiched vertically between the gear cover 78 and the gear body 76, and the gear body side support hole 76C and cover side support hole 78C of the crank gear 74 and the coupling side support hole 72B of the coupling 72 are arranged opposite each other in the vertical direction. As a result, the damper spring 80 can be placed in the recess 76A of the gear body 76, and the crank gear 74 and the coupling 72 can be connected so that they can rotate as a single unit by the damper spring 80. Therefore, the size of the gear mechanism 70, including the damper spring 80, can be reduced.

[0068] Furthermore, the gear portion 76F provided on the outer circumference of the gear body 76 meshes with the gear portion of the transmission gear 44 that receives the driving force of the motor 40. This allows the driving force of the motor 40 to be transmitted to the crank gear 74 with a simple configuration.

[0069] Furthermore, the fixed shaft 72A of the coupling 72 protrudes downward through the body-side insertion hole 76B of the gear body 76, and also protrudes upward through the cover-side insertion hole 78A of the gear cover 78. A retaining ring 82 provided at the lower end of the fixed shaft 72A restricts the downward movement of the gear body 76 relative to the coupling 72, and a retaining ring 84 provided at the upper end of the fixed shaft 72A restricts the upward movement of the gear cover 78 relative to the coupling 72. This allows the gear mechanism 70 to be unitized. Therefore, the gear mechanism 70 can be mounted on the crankshaft 48 by press-fitting the unitized gear mechanism 70 onto the crankshaft 48. Thus, this contributes to improving the ease of assembly of the drive force transmission mechanism 42.

[0070] Furthermore, in the gear mechanism 70, the body-side insertion hole 76B of the gear body 76 is rotatably supported on the fixed shaft 72A of the coupling 72, and the cover-side insertion hole 78A of the gear cover 78 is rotatably supported on the fixed shaft 72A. This improves the ease of assembly of the gear mechanism 70 when it is unitized.

[0071] Furthermore, the inner case 32 is supported by the support cylinder portion 14A of the housing 10 in the support mechanism 60 so as to be movable relative to the housing 10 in the front-rear direction. The support mechanism 60 includes an upper vibration-damping spring 64 and a lower vibration-damping spring 66 that bias the inner case 32 forward, and a vibration-damping leaf spring 68. When the tip tool T is pressed against the workpiece during machining, the inner case 32 floats relative to the housing 10 while being biased forward by the upper vibration-damping spring 64, the lower vibration-damping spring 66, and the vibration-damping leaf spring 68. As a result, when the inner case 32 vibrates in the front-rear direction relative to the housing 10 due to the operation of the drive force transmission mechanism 42, the vibration can be absorbed by the elastically deforming upper vibration-damping spring 64, the lower vibration-damping spring 66, and the vibration-damping leaf spring 68. Consequently, the transmission of such vibration to the handle 12A can be suppressed by the support mechanism 60 in addition to the gear mechanism 70. Therefore, vibrations transmitted to the handle 12A can be suppressed more effectively. Thus, the workability of the hammer 1 can be effectively improved.

[0072] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. [Explanation of Symbols]

[0073] 1. Hammer (working tool) 12A Handle 32 Inner Case (Case) 40 Motor (drive unit) 42. Power transmission mechanism (power transmission section) 44 Transmission gear (drive gear) 46 Crank mechanism 48 Crankshaft 48B Eccentric shaft 52 pistons 54 Piston Rod 64 Upper vibration damping spring (external vibration reduction section) 66 Lower vibration damping spring (external vibration reduction section) 68 Vibration-damping plate spring (external vibration reduction section) 72 Coupling (driven rotating part) 72A Fixed shaft (shaft) 72B Coupling side support hole (driven side support part) 74 Crank gear (drive side rotating part) 76 Gear body (main body) 76A recess 76C Gear body side support hole (drive side support part) 76F Gear section (external teeth) 78 Gear cover (cover) 78C Cover-side support hole (drive-side support part) 80. Damper spring (elastic part, inner vibration reduction part) 82 Retaining ring 84 Retaining ring AL axis T Tip tool

Claims

1. The drive unit and A tip tool that operates by receiving the driving force of the aforementioned drive unit, A drive force transmission unit that transmits the driving force of the drive unit to the tip tool, Equipped with, The aforementioned drive force transmission unit is A drive-side rotating part that rotates about an axis extending in a predetermined direction, receiving the driving force of the aforementioned drive unit, A driven rotating part that receives the rotational force of the driving rotating part and rotates about the axis to transmit the driving force of the driving part to the tip tool, An elastic part interposed between the driving rotating part and the driven rotating part transmits the rotational force of the driving rotating part to the driven rotating part, and undergoes elastic deformation as the driven rotating part rotates relative to the driving rotating part, Equipped with, The drive-side rotating portion has a drive-side support portion that supports the elastic portion in the rotational direction of the drive-side rotating portion, The driven rotating portion has a driven support portion that supports the elastic portion in the direction of rotation, A work machine in which the drive-side support portion and the driven-side support portion are arranged facing each other in the predetermined direction.

2. The work machine according to claim 1, wherein the drive-side support portion and the driven-side support portion support the elastic portion from both sides in the direction of rotation.

3. Multiple of the drive-side support portions are provided on the drive-side rotating portion and are arranged in the direction of rotation. The work machine according to claim 1, wherein a plurality of the driven support portions are provided on the driven rotating portion and are arranged in the direction of rotation.

4. The drive-side support portion is an elongated hole extending in the rotational tangential direction of the drive-side rotating portion, and the driven-side support portion is an elongated hole extending in the rotational tangential direction of the drive-side rotating portion. The work machine according to claim 1, wherein the elastic portion is a compression coil spring disposed inside the drive-side support portion and the driven-side support portion and extending in the longitudinal direction of the drive-side support portion and the driven-side support portion.

5. The work machine according to claim 1, wherein the drive-side rotating part has a recess that is open to one side in the predetermined direction, and at least a part of the driven-side rotating part is disposed within the recess.

6. The aforementioned drive-side rotating part is A bottomed cylindrical body portion having the aforementioned recess, A cover is assembled to the main body so as to be integrally rotatable, and which closes the recess and sandwiches the driven rotating part in the predetermined direction together with the main body, It consists of, The work machine according to claim 5, wherein the drive-side support portion is provided on the main body portion and the cover portion, and the drive-side support portion provided on the main body portion and the drive-side support portion provided on the cover portion sandwich the driven-side support portion in the predetermined direction.

7. A drive gear is provided on the radially outer side of the main body, which rotates in response to the driving force of the drive unit. The work machine according to claim 6, wherein the outer circumference of the main body is provided with external teeth that mesh with the drive gear.

8. The driven rotating part has a shaft portion with the axis as its axis, and both axial ends of the shaft portion protrude from the driving rotating part on both sides in the predetermined direction. The work machine according to claim 5, wherein retaining rings are provided at both axial ends of the shaft portion, and the relative movement of the drive-side rotating portion with respect to the driven-side rotating portion in the predetermined direction is restricted by the retaining rings.

9. A crank mechanism is connected to the aforementioned driven rotating part. The aforementioned crank mechanism is A crankshaft extending along the aforementioned axis and connected to the driven rotating part so as to be rotatable integrally with it, An eccentric shaft is configured to rotate integrally with the crankshaft and is positioned eccentrically with respect to the crankshaft, A piston is connected to the eccentric shaft via a piston rod and moves back and forth in an orthogonal direction perpendicular to the predetermined direction by the rotation of the crankshaft, The work machine according to claim 1, comprising the above.

10. The drive unit and A tip tool that operates by receiving the driving force of the aforementioned drive unit, A drive force transmission unit that transmits the driving force of the drive unit to the tip tool, A case housing the drive unit and the drive force transmission unit, A housing that supports the aforementioned case so as to be movable relative to it and has a handle for the worker to grip, An external vibration reduction unit is provided between the case and the housing to suppress the transmission of vibrations generated when the drive force transmission unit is operating from the case to the handle, An internal vibration reduction unit, housed within the case, suppresses the transmission of vibrations generated during the operation of the drive force transmission unit to the case, A work machine equipped with the following features.

11. The aforementioned drive force transmission unit is A drive-side rotating part that rotates about an axis extending in a predetermined direction, receiving the driving force of the aforementioned drive unit, A driven rotating part that receives the rotational force of the driving rotating part and rotates about the axis to transmit the driving force of the driving part to the tip tool, Equipped with, The work machine according to claim 10, wherein the internal vibration reduction part is interposed between the driving side rotating part and the driven side rotating part.

12. The internal vibration reduction section is configured to be elastically deformable and is supported by the driving side rotating section and the driven side rotating section. The work machine according to claim 11, wherein the internal vibration reducing portion is elastically deformed as the driven rotating portion rotates relative to the driving rotating portion.

13. The external vibration reduction section is configured to be elastically deformable and is supported by the case and the housing. The work machine according to claim 12, wherein the outer vibration reducing part elastically deforms as the case moves relative to the housing.

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