power tools

Abstract

To provide an electric tool reduced in generation of noise.SOLUTION: An electric tool 1 includes a driving shaft 30, a hammer 40, an anvil 50, an output shaft 60, and a housing. The hammer 40 rotates by transmission of rotation force from the driving shaft 30 rotating in response to the rotation of a motor shaft 21. The anvil 50 rotates by application of impact from the hammer 40 due to the rotation of the hammer 40. The output shaft 60 is engaged with the anvil 50 in a rotation direction, and rotates in response to the rotation of the anvil 50. The housing covers at least the hammer 40 and the anvil 50, and supports the output shaft 60 via a bearing part 70. The anvil 50 faces the output shaft 60 via a gap GP1 in the axial direction. The driving shaft 30 is provided so as to be rotatable relative to the output shaft 60. The driving shaft 30 regulates the output shaft 60 from moving in a direction approaching the driving shaft 30 in the axial direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a power tool. More specifically, the present disclosure relates to a power tool including a motor. Background Art

[0002] Patent Document 1 discloses an impact rotary tool. The impact rotary tool of Patent Document 1 includes a bit holder capable of mounting a driver bit or the like at a front end of an anvil that rotates when struck by a hammer. Prior Art Documents Patent Documents

[0003] Patent Document 1 Japanese Unexamined Patent Publication No. 2010-76022 Summary of the Invention Problem to be Solved by the Invention

[0004] In the impact rotary tool described in Patent Document 1, when the hammer strikes the anvil, an axial impact is applied from the hammer to the anvil. When the axial impact applied to the anvil is transmitted to the housing, the housing may vibrate and generate noise.

[0005] An object of the present disclosure is to provide a power tool capable of reducing noise generation. Means for Solving the Problem

[0006] A power tool according to one aspect of the present disclosure comprises a drive shaft, a hammer, an anvil, an output shaft, and a housing. The drive shaft rotates in accordance with the rotation of a motor shaft of a motor. The hammer rotates as rotational force is transmitted from the drive shaft. The anvil rotates as it is struck by the hammer as the hammer rotates. The output shaft is capable of mounting a tool tip. The output shaft engages with the anvil in the rotational direction and rotates in accordance with the rotation of the anvil. The housing covers at least the hammer and the anvil and supports the output shaft via a bearing. The output shaft has one or more second teeth that mesh in the rotational direction with one or more first teeth provided on the anvil. The meshing of the one or more first teeth and the one or more second teeth causes the output shaft and the anvil to engage in the rotational direction. The drive shaft is provided so as to be rotatable relative to the output shaft. A damping member is provided between the drive shaft and the output shaft to reduce axial vibrations transmitted between the output shaft and the drive shaft. The damping member provided between the drive shaft and the output shaft restricts the output shaft from moving toward the drive shaft in the axial direction, so that when the output shaft and the anvil are engaged in the rotational direction, a gap is provided between the one or more first teeth and the output shaft in the axial direction, and a gap is provided between the one or more second teeth and the anvil in the axial direction. The drive shaft includes a drive member that rotates in accordance with the rotation of the motor shaft and transmits rotational force to the hammer, and a shaft member disposed between the cushioning member and the drive member. The shaft member is capable of contacting the cushioning member. The drive member is provided so as to be rotatable relative to the shaft member. A power tool in another aspect of the present disclosure comprises a drive shaft, a hammer, an anvil, an output shaft, and a housing. The drive shaft rotates in accordance with the rotation of a motor shaft of a motor. The hammer rotates as rotational force is transmitted from the drive shaft. The anvil rotates as it is struck by the hammer as the hammer rotates. The output shaft is capable of mounting a tool tip. The output shaft engages with the anvil in the rotational direction and rotates in accordance with the rotation of the anvil. The housing covers at least the hammer and the anvil and supports the output shaft via bearings. The output shaft has one or more second teeth that mesh in the rotational direction with one or more first teeth provided on the anvil. The meshing of the one or more first teeth and the one or more second teeth causes the output shaft to engage with the anvil in the rotational direction. The drive shaft is rotatable relative to the output shaft. A damping member is provided between the drive shaft and the output shaft to reduce axial vibrations transmitted between the output shaft and the drive shaft. The damping member provided between the drive shaft and the output shaft restricts the output shaft from moving toward the drive shaft in the axial direction, thereby providing a gap in the axial direction between the one or more first teeth and the output shaft without any other members intervening, and a gap in the axial direction between the one or more second teeth and the anvil without any other members intervening, when the output shaft and the anvil are engaged in the rotational direction. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide a power tool that can reduce noise generation. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an external perspective view of a power tool according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a cross-sectional view of the main part of the same power tool. [Figure 3]Figure 3 is a side view of the drive mechanism of the same power tool. [Figure 4] Figure 4 is a perspective view of the drive mechanism of the same power tool. [Figure 5] Figure 5 is an exploded perspective view of the drive mechanism of the same power tool. [Figure 6] Figure 6 is a perspective view of the anvil and output shaft of the same power tool as described above, assembled together. [Modes for carrying out the invention]

[0009] The following description of the power tools according to the embodiments will be illustrated with reference to the drawings. However, the embodiments described below are only one of many embodiments of this disclosure. The embodiments described below can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved. Furthermore, the figures described in the embodiments below are schematic diagrams, and the ratios of the size and thickness of each component in the figures do not necessarily reflect the actual dimensional ratios.

[0010] (Embodiment) (1) Overview The following describes the outline of the power tool 1 according to this embodiment with reference to Figures 1 and 2.

[0011] As shown in Figures 1 and 2, the power tool 1 according to this embodiment comprises a drive shaft 30, a hammer 40, an anvil 50, an output shaft 60, and a housing 10.

[0012] The drive shaft 30 rotates in accordance with the rotation of the motor shaft 21 of the motor 20.

[0013] The hammer 40 rotates as rotational force is transmitted from the drive shaft 30.

[0014] Anvil 50 rotates as it is struck by the rotation of Hammer 40.

[0015] The output shaft 60 is capable of mounting a tip tool B1. The output shaft 60 engages with the anvil 50 in the rotational direction, and rotates in accordance with the rotation of the anvil 50.

[0016] The housing 10 covers at least the hammer 40 and the anvil 50, and supports the output shaft 60 via a bearing portion 70.

[0017] The anvil 50 opposes the output shaft 60 in the axial direction via a gap GP1.

[0018] The drive shaft 30 is provided so as to be rotatable relative to the output shaft 60.

[0019] The drive shaft 30 restricts movement of the output shaft 60 in the axial direction in a direction approaching the drive shaft 30.

[0020] In the present embodiment, each of the drive shaft 30, the hammer 40, the anvil 50, and the output shaft 60 is arranged to be rotatable about a rotation axis AX1, and the direction along the rotation axis AX1 is the axial direction of the drive shaft 30, the hammer 40, the anvil 50, and the output shaft 60.

[0021] The power tool 1 of the present embodiment has an impact mechanism constituted by the hammer 40, the anvil 50, and the like. That is, the power tool 1 of the present embodiment is an electric impact power tool that performs tightening work or the like for tightening a fastening component (for example, a screw, a bolt, a nut, etc.) of a work target with the tip tool B1 while performing an impact operation by the impact mechanism. In the impact operation, the impact mechanism generates an impact force based on the power of the motor 20, and the impact force acts on the tip tool B1.

[0022] According to this embodiment, since the anvil 50 and the output shaft 60 face each other with a gap GP1 in between, when the tip tool B1 is pressed against the workpiece, no force is applied to the output shaft 60 via the anvil 50. Furthermore, since the drive shaft 30 restricts the output shaft 60 from moving toward the drive shaft 30, the force applied to the output shaft 60 when the tip tool B1 is pressed against the workpiece can be received by the drive shaft 30. As a result, when the hammer 40 strikes the anvil 50, the impact force applied from the hammer 40 to the anvil 50 is less likely to be applied to the output shaft 60, reducing axial vibrations applied to the output shaft 60 and reducing noise generated from the power tool 1.

[0023] (2) Detailed configuration (2.1) Overall structure The detailed configuration of the power tool 1 of this embodiment will be described with reference to Figures 1 to 6.

[0024] As described above, the power tool 1 comprises a drive shaft 30, a hammer 40, an anvil 50, and an output shaft 60. The power tool 1 also further comprises a damping member 80. The damping member 80 is provided between the output shaft 60 and the drive shaft 30. The damping member 80 reduces axial vibrations transmitted between the output shaft 60 and the drive shaft 30.

[0025] The housing 10 includes, for example, an inner case 16 that houses a drive shaft 30, a hammer 40, an anvil 50, and an output shaft 60, and an outer case 11 that houses the components including the inner case 16. The outer case 11 includes a cylindrical portion 12 that houses the inner case 16, a base portion 14 to which a battery pack is attached, and a grip portion 13 that connects the cylindrical portion 12 and the base portion 14.

[0026] In the following description, the axial direction D1 of the output shaft 60 (the axial direction of the rotation axis AX1) is defined as the front-rear direction, the side of the anvil 50 as viewed from the hammer 40 is defined as the front, and the side of the hammer 40 as viewed from the anvil 50 is defined as the rear. Furthermore, the direction in which the cylindrical part 12, the grip part 13, and the base part 14 are aligned is defined as the up-down direction, the side of the cylindrical part 12 as viewed from the base part 14 is defined as the top, and the side of the base part 14 as viewed from the cylindrical part 12 is defined as the bottom. In addition, the direction perpendicular to the front-rear direction and the up-down direction is defined as the left-right direction. However, these definitions are not intended to define the direction of use of the power tool 1.

[0027] As described above, the outer case 11 of the power tool 1 comprises a cylindrical portion 12, a grip portion 13, and a base portion 14.

[0028] The base unit 14 is detachable from the battery pack, which is the power source for the power tool 1.

[0029] One end of the grip portion 13 is connected to a part of the circumferential surface of the cylindrical portion 12, and the other end of the grip portion 13 is connected to the base portion 14. The grip portion 13 is the part that the user holds with their hand when performing work on fastening parts (e.g., bolts, etc.) using the power tool 1 (e.g., bolt tightening work). The grip portion 13 is provided with a trigger switch operating part 15. In other words, the power tool 1 of this embodiment is a portable tool that the user holds in their hand and uses.

[0030] Furthermore, the housing 10 contains a control circuit and the like that rotates the motor 20 when the operating unit 15 is operated.

[0031] Inside the cylindrical section 12 is a drive mechanism 2 (see Figures 2 to 5) that rotates the output shaft 60 in accordance with the rotation of the motor 20. The drive mechanism 2 consists of the motor 20, a transmission mechanism 22, a drive shaft 30, a hammer 40, an anvil 50, and the output shaft 60, etc.

[0032] The configuration of the drive mechanism 2 will be explained below with reference to Figures 2 to 6.

[0033] Motor 20 is composed of, for example, a servo motor. The rotation of motor 20 is controlled by a control circuit.

[0034] The transmission mechanism 22 is composed of, for example, a planetary gear mechanism. The transmission mechanism 22 is connected to the motor shaft 21 of the motor 20 and transmits the rotation of the motor shaft 21 to the shaft 23 at a predetermined gear ratio. The shaft 23 of the transmission mechanism 22 is connected to the drive shaft 30.

[0035] The drive shaft 30 includes a drive member 31 that rotates in accordance with the rotation of the motor shaft 21 and transmits rotational force to the hammer 40, and a shaft member 32 that is positioned between the cushioning member 80 and the drive member 31.

[0036] The drive member 31 is formed in a cylindrical shape from, for example, a metal material and is rotatably arranged inside the housing 10. A shaft hole 310 is provided at the rear of the drive member 31, and the drive member 31 and the shaft 23 of the transmission mechanism 22 are coupled when the shaft 23 of the transmission mechanism 22 is inserted into the shaft hole 310. The drive member 31 rotates in conjunction with the rotation of the shaft 23 of the transmission mechanism 22. That is, the drive member 31 rotates in accordance with the rotation of the motor shaft 21 of the motor 20. The transmission mechanism 22 converts the rotational speed and rotational torque of the motor shaft 21 into the rotational speed and torque necessary to rotate the fastening component.

[0037] A groove 311 is provided on the circumferential surface of the front portion of the drive member 31 into which a pair of steel balls 42 are inserted. The groove 311 is arranged to meander back and forth in the circumferential direction. In addition, a ring-shaped spring seat 312 is attached to the rear of the drive member 31 to receive the rear end of the coil spring 33.

[0038] The shaft member 32 is formed in a cylindrical shape, for example, from a metal material. The shaft member 32 is positioned in front of the drive member 31. The rear surface of the shaft member 32 is in contact with the front surface of the drive member 31, and the front surface of the shaft member 32 is in contact with the cushioning member 80. The shaft member 32 has the function of positioning the cushioning member 80 in the front-rear direction. The shaft member 32 and the drive member 31 are not mechanically coupled, and the drive member 31 is provided so as to be rotatable relative to the shaft member 32.

[0039] The hammer 40 is formed in a cylindrical shape, for example, from a metal material, with a diameter greater than its axial length.

[0040] The hammer 40 has a shaft hole 41 at its center that penetrates it in the front-to-back direction. By inserting the front portion of the drive member 31 into the shaft hole 41 of the hammer 40, the hammer 40 is assembled with respect to the drive member 31 in a state that allows it to move along the rotation axis AX1 and move in the circumferential direction about the rotation axis AX1 (i.e., rotate).

[0041] The inner circumferential surface of the shaft hole 41 of the hammer 40 is provided with a pair of grooves 44 into which a pair of steel balls 42 are inserted. When the front portion of the drive member 31 is inserted into the shaft hole 41 of the hammer 40, the pair of steel balls 42 are sandwiched between the pair of grooves 44 of the hammer 40 and the groove 311 of the drive member 31. Here, the pair of grooves 44, the groove 311, and the pair of steel balls 42 constitute a cam mechanism. When the drive member 31 rotates, the rotation of the drive member 31 is transmitted to the hammer 40 by the movement of the pair of steel balls 42 in the space enclosed by the groove 311 and the pair of grooves 44 in accordance with the rotation of the drive member 31, and the hammer 40 rotates relative to the drive member 31 while moving forward or backward along the axial direction of the drive member 31 (the direction parallel to the rotation axis AX1).

[0042] An annular groove 43 concentric with the shaft hole 41 is provided on the rear surface of the hammer 40. Multiple steel balls 46 are arranged inside the groove 43. The multiple steel balls 46 are positioned between the ring-shaped member 47 and the bottom of the groove 43. The front end of the coil spring 33 is inserted into the groove 43, and the front end of the coil spring 33 is in contact with the ring-shaped member 47. As a result, the hammer 40 receives a force from the coil spring 33 in the direction toward the output shaft 60 (i.e., forward) along the axial direction (i.e., the rotation axis AX1). Furthermore, since a pair of steel balls 46 are positioned between the ring-shaped member 47, which the front end of the coil spring 33 contacts, and the bottom of the groove 43, the hammer 40 is rotatable relative to the coil spring 33.

[0043] As described above, the hammer 40 can move forward (towards the output shaft 60) or backward (away from the output shaft 60) along the rotation axis AX1. Hereafter, when the hammer 40 moves forward, it will be referred to as "the hammer 40 moves forward," and when the hammer 40 moves backward, it will be referred to as "the hammer 40 moves backward."

[0044] The front of the hammer 40 is provided with a pair of projections 45 that protrude forward. The pair of projections 45 are positioned diagonally with respect to the rotation axis AX1 when viewed from the front. When viewed from the front of the hammer 40, each of the projections 45 is fan-shaped.

[0045] The anvil 50 is formed in a cylindrical shape, for example, from a metal material. The anvil 50 has a large-diameter portion 51 at its rear, which has a larger outer diameter than the front portion. A pair of radially projecting protrusions 52 are provided on the outer circumferential surface of the large-diameter portion 51 at positions diagonally opposite to the rotation axis AX1.

[0046] A through-hole 53 is provided at the center of the anvil 50, penetrating it in the front-to-back direction. The front end portion of the drive member 31 and a cylindrical shaft member 32 are positioned in the through-hole 53. In other words, the shaft member 32 can come into contact with the buffer member 80.

[0047] As shown in Figures 3 to 6, the front surface of the anvil 50 is provided with a pair of first teeth 54 that protrude forward. The pair of first teeth 54 are positioned diagonally with respect to the rotation axis AX1 when viewed from the front. In addition, the front surface of the anvil 50 is provided with a pair of recesses 55 between the pair of first teeth 54.

[0048] The cushioning member 80 is made of an elastic material. The cushioning member 80 is formed in a disc shape from an elastic material such as synthetic rubber. The cushioning member 80 is positioned between the shaft member 32 and the output shaft 60.

[0049] The output shaft 60 is formed in a cylindrical shape, for example, from a metal material. The output shaft 60 is rotatably held in the inner case 16 via a bearing portion 70. A recess 61 (see Figure 2) into which a cushioning member 80 is inserted is provided on the rear surface of the output shaft 60.

[0050] As shown in Figures 3 to 6, a pair of second teeth 62 projecting backward are provided on the periphery of the recess 61 on the rear surface of the output shaft 60. The pair of second teeth 62 are positioned diagonally with respect to the rotation axis AX1 when viewed from the front. Additionally, a recess 63 is provided on the periphery of the recess 61 on the rear surface of the output shaft 60 in the area between the pair of second teeth 62. When the anvil 50 and the output shaft 60 are assembled, the pair of first teeth 54 and the pair of second teeth 62 mesh with each other, thereby reliably engaging the anvil 50 and the output shaft 60 in the rotational direction, and the output shaft 60 rotates in accordance with the rotation of the anvil 50. When the anvil 50 and the output shaft 60 are assembled, a gap GP1 is provided between the anvil 50 and the output shaft 60 in the axial direction D1, and the anvil 50 and the output shaft 60 face each other with the gap GP1 in between. Furthermore, since a buffer member 80 is interposed between the drive shaft 30 and the output shaft 60, the drive shaft 30 is provided to be rotatable relative to the output shaft 60. In addition, the front surface of the buffer member 80 is in contact with the rear surface of the output shaft 60, and the front surface of the shaft member 32 is in contact with the rear surface of the buffer member 80, so the drive shaft 30 restricts the output shaft 60 from moving toward the drive shaft 30 in the axial direction.

[0051] The front end of the output shaft 60 is inserted into a hole 17 in the inner case 16 and protrudes to the outside of the inner case 16. A rectangular prism-shaped mounting portion 64 is provided at the front end of the output shaft 60. A socket 65, to which a tip tool B1 can be attached, is mounted on the mounting portion 64. The socket 65 attached to the mounting portion 64 of the output shaft 60 protrudes to the outside of the outer case 11 through a hole 18 in the outer case 11. The output shaft 60 can hold the tip tool B1 via the socket 65. The tip tool B1 is, for example, a screwdriver bit. By rotating the tip tool B1 while it is engaged with the fastening part, it becomes possible to tighten or loosen the fastening part. Note that the socket 65 is not an essential component of the power tool 1, and the tip tool B1 may be directly attached to the output shaft 60 in a detachable manner.

[0052] Furthermore, the power tool 1 of this embodiment includes a first movement restricting part 91 (see Figure 2) that restricts the anvil 50 from moving away from the hammer 40 in the axial direction (along the rotation axis AX1, which is the rotation center of the anvil 50). The first movement restricting part 91 is, for example, a ring-shaped component made of synthetic resin held in the inner case 16. The anvil 50 is inserted into the central hole of the first movement restricting part 91, and the first movement restricting part 91 abuts against a stepped portion 56 provided on the outer circumferential surface of the anvil 50 from the front. By the first movement restricting part 91 abutting the stepped portion 56 of the anvil 50 from the front, the forward movement of the anvil 50 can be restricted.

[0053] As described above, the first movement restricting portion 91 is provided in the housing 10 (specifically, the inner case 16). Here, it is preferable that the first movement restricting portion 91 is made of an elastic material. For example, it is preferable that the first movement restricting portion 91 is made of an elastic material such as synthetic rubber, as this can reduce the transmission of vibrations of the anvil 50 in the axial direction to the housing 10, and reduce the noise generated due to the vibrations of the anvil 50.

[0054] Furthermore, the power tool 1 of this embodiment is further equipped with a second movement restricting part 92 (see Figure 2) that restricts the output shaft 60 from moving away from the anvil 50 in the axial direction (the direction along the rotation axis AX1, which is the rotation center of the output shaft 60). The second movement restricting part 92 is, for example, a retaining ring C placed in the hole 17 of the inner case 16. The second movement restricting part 92 restricts the forward movement of the output shaft 60 by contacting the stepped portion 66 provided on the outer circumferential surface of the output shaft 60 from the front, thereby limiting the movement of the output shaft 60.

[0055] (2.2) Operation Instructions When a user uses the power tool 1 to fasten fastening parts, the user attaches a battery pack to the base 14 of the power tool 1 and attaches the tip tool B1 to the socket 65 attached to the output shaft 60. Then, when the user holds the grip 13 and operates the operating unit 15 with the tip tool B1 pressed against the fastening part, the control circuit sends a drive current corresponding to the amount of operation of the operating unit 15 to the windings of the motor 20, causing the motor shaft 21 of the motor 20 to rotate at a rotational speed corresponding to the amount of operation of the operating unit 15. When the motor shaft 21 rotates, the rotation of the motor shaft 21 is transmitted to the drive member 31 via the transmission mechanism 22, causing the drive member 31 to rotate. When the drive member 31 rotates, the rotation of the drive member 31 is transmitted to the hammer 40 via the cam mechanism, causing the hammer 40 to rotate together with the drive member 31. When the hammer 40 rotates, the projection 45 of the hammer 40 pushes the projection 52 of the anvil 50, causing the anvil 50 to rotate. Since the anvil 50 and the output shaft 60 are engaged in the rotational direction, the rotation of the anvil 50 causes the output shaft 60 to rotate, and the tip tool B1 held on the output shaft 60 via the socket 65 rotates.

[0056] Here, if the magnitude of the torque applied from the fastening component to the output shaft 60 by the output shaft 60 rotating the fastening component (hereinafter referred to as load torque) is less than or equal to a predetermined value, the hammer 40 rotates together with the drive member 31, and the output shaft 60 rotates in accordance with the rotation of the hammer 40.

[0057] Meanwhile, as the fastening of the fastening components progresses and the load torque exceeds a predetermined value, the impact mechanism performs an impact operation. As the load torque increases, the component of the force generated between the anvil 50 and the hammer 40 that moves the hammer 40 backward increases. When the load torque exceeds a predetermined value, the hammer 40 moves backward while compressing the coil spring 33. As the hammer 40 moves backward, the projection 45 of the hammer 40 passes over the projection 52 of the anvil 50, and the hammer 40 moves forward while rotating, receiving the elastic force of the coil spring 33. When the hammer 40 has rotated approximately half a turn, the pair of projections 45 of the hammer 40 collide with the sides of the pair of projections 52 of the anvil 50, and a striking force (rotational striking force) is applied from the hammer 40 to the anvil 50, causing the anvil 50 to rotate, and the rotation of the anvil 50 causes the tip tool B1 held on the output shaft 60 to rotate. The power tool 1 repeatedly performs an impact operation until the tightening torque of the fastening component reaches a predetermined torque setting value. When the tightening torque of the fastening component reaches the torque setting value, the control circuit stops the excitation of the motor 20 and stops the rotation of the motor 20.

[0058] In this configuration, the anvil 50 and the output shaft 60 are engaged in the rotational direction, but face each other in the axial direction with a gap GP1 in between. Furthermore, since a damping member 80 is interposed between the drive shaft 30 and the output shaft 60, there is no direct path for axial vibrations to be transmitted from the drive shaft 30 to the output shaft 60. Therefore, even if axial vibrations occur in the drive shaft 30 during impact operation, the damping member 80 makes it difficult for these vibrations to be transmitted to the output shaft 60, thereby reducing the noise generated by axial vibrations. Additionally, when the tip tool B1 is pressed against the fastening component, the force applied to the output shaft 60 is transmitted to the drive shaft 30 via the damping member 80. Here, the damping member 80 suppresses axial vibrations transmitted from the output shaft 60 to the drive shaft 30, making it difficult for axial vibrations to be transmitted to the housing 10, thereby reducing the noise generated by axial vibrations.

[0059] Furthermore, when an impact operation is performed, the hammer 40 applies a striking force to the anvil 50, causing axial vibration to be applied to the anvil 50. However, the first movement restricting part 91 contacts the stepped portion 56 of the anvil 50 from the front, thereby restricting the anvil 50 from moving toward the output shaft 60 (i.e., forward). This reduces the possibility of the anvil 50 and the output shaft 60 coming into contact in the axial direction, and reduces the possibility of axial vibration being transmitted from the anvil 50 to the output shaft 60. In addition, the first movement restricting part 91 is interposed between the anvil 50 and the inner case 16, and since the first movement restricting part 91 is made of an elastic material, it can reduce vibration transmitted from the anvil 50 to the inner case 16. Therefore, it is possible to suppress the generation of noise from the power tool 1 due to vibration of the anvil 50.

[0060] Furthermore, in this embodiment, the second movement restricting unit 92 contacts the stepped portion 66 of the output shaft 60 from the front, thereby restricting the output shaft 60 from moving away from the anvil 50 in the axial direction (i.e., forward). This makes it more difficult for the anvil 50 and the output shaft 60 to disengage in the rotational direction, and reduces the loss when applying rotational force from the anvil 50 to the output shaft 60.

[0061] Furthermore, in this embodiment, the drive shaft 30 is composed of a drive member 31 that rotates in accordance with the rotation of the motor shaft 21 and a shaft member 32, and the drive member 31 is provided to be rotatable relative to the shaft member 32. This makes it possible to reduce the rotation of the shaft member 32 that contacts the cushioning member 80 compared to the drive member 31. Therefore, it is possible to suppress wear of the cushioning member 80 due to friction between the shaft member 32 and the cushioning member 80 caused by the rotation of the shaft member 32.

[0062] The above embodiments are merely one of many embodiments of this disclosure. These embodiments can be modified in various ways depending on the design, etc., as long as they achieve the objectives of this disclosure.

[0063] In the above embodiment, the drive shaft 30 was divided into two members, a drive member 31 and a shaft member 32, but the drive shaft 30 may be composed of a single member. That is, the drive member 31, which rotates in accordance with the rotation of the motor shaft 21, may be in direct contact with the buffer member 80.

[0064] The first movement restricting section 91 is formed of an elastic material such as synthetic rubber, but it may be made of a material other than synthetic rubber. The material of the first movement restricting section 91 can be changed as appropriate, as long as it has a larger elastic modulus than the drive shaft 30.

[0065] Furthermore, although the second movement restricting section 92 is formed of, for example, a metal material, the material of the second movement restricting section 92 may be synthetic resin, as long as it can restrict the forward movement of the output shaft 60, and can be changed as appropriate.

[0066] (summary) Based on the embodiments described above, the following aspects are disclosed.

[0067] The power tool (1) in the first embodiment comprises a drive shaft (30), a hammer (40), an anvil (50), an output shaft (60), and a housing (10). The drive shaft (30) rotates in accordance with the rotation of the motor shaft (21) of the motor (20). The hammer (40) rotates as rotational force is transmitted from the drive shaft (30). The anvil (50) rotates as it is struck by the hammer (40) as the hammer (40) rotates. The output shaft (60) is capable of mounting a cutting tool (B1). The output shaft (60) engages with the anvil (50) in the rotational direction and rotates in accordance with the rotation of the anvil (50). The housing (10) covers at least the hammer (40) and the anvil (50) and supports the output shaft (60) via a bearing portion (70). The anvil (50) faces the output shaft (60) in the axial direction with a gap (GP1) between them. The drive shaft (30) is rotatable relative to the output shaft (60). The drive shaft (30) restricts the output shaft (60) from moving toward the drive shaft (30) in the axial direction.

[0068] In this embodiment, since the anvil (50) and the output shaft (60) face each other with a gap (GP1) in between, when the tip tool (B1) is pressed against the workpiece, no force is applied to the output shaft (60) via the anvil (50). Furthermore, since the drive shaft (30) restricts the output shaft (60) from moving toward the drive shaft (30), the force applied to the output shaft (60) when the tip tool (B1) is pressed against the workpiece can be received by the drive shaft (30). As a result, when the hammer (40) strikes the anvil (50), the impact force applied from the hammer (40) to the anvil (50) is less likely to be applied to the output shaft (60), reducing axial vibrations applied to the output shaft (60) and reducing noise generated from the power tool (1).

[0069] In the second embodiment of the power tool (1), as in the first embodiment, a damping member (80) is provided between the output shaft (60) and the drive shaft (30) to reduce axial vibrations transmitted between the output shaft (60) and the drive shaft (30).

[0070] According to this embodiment, the noise generated from the power tool (1) can be further reduced.

[0071] In the third embodiment of the power tool (1), in the second embodiment, the drive shaft (30) includes a drive member (31) and a shaft member (32). The drive member (31) rotates in accordance with the rotation of the motor shaft (21) and transmits rotational force to the hammer (40). The shaft member (32) is positioned between the buffer member (80) and the drive member (31). The shaft member (32) is capable of contacting the buffer member (80). The drive member (31) is rotatable relative to the shaft member (32).

[0072] In this embodiment, since the drive member (31) is provided so as to be rotatable relative to the shaft member (32), the rotation of the shaft member (32) in contact with the cushioning member (80) can be reduced compared to that of the drive member (31). Therefore, wear of the cushioning member (80) due to the rotation of the shaft member (32) can be suppressed.

[0073] In the power tool (1) of the fourth embodiment, the cushioning member (80) is made of an elastic material, as in the second or third embodiment.

[0074] According to this embodiment, axial vibrations applied from the drive shaft (30) to the output shaft (60) via the damping member (80) can be reduced.

[0075] In the fifth embodiment of the power tool (1), in any of the first to fourth embodiments, a first movement restricting unit (91) is further provided which restricts the anvil (50) from moving axially away from the hammer (40).

[0076] In this embodiment, the first movement restricting unit (91) can restrict the anvil (50) from moving toward the output shaft (60). Therefore, the possibility of the anvil (50) and the output shaft (60) coming into contact in the axial direction can be reduced, and the possibility of axial vibrations being transmitted from the anvil (50) to the output shaft (60) can be reduced.

[0077] In the sixth embodiment of the power tool (1), as in the fifth embodiment, the first movement restricting portion (91) is provided in the housing (10), and the first movement restricting portion (91) is made of an elastic material.

[0078] According to this embodiment, the first movement restricting portion (91) formed of an elastic material can reduce the axial shock transmitted from the anvil (50) to the housing (10), and can further reduce the noise generated from the power tool (1).

[0079] In the seventh embodiment of the power tool (1), in any of the first to sixth embodiments, a second movement restricting unit (92) is further provided which restricts the output shaft (60) from moving away from the anvil (50) in the axial direction.

[0080] According to this embodiment, the second movement restricting unit (92) restricts the output shaft (60) from moving away from the anvil (50) in the axial direction, which has the advantage that the engagement between the anvil (50) and the output shaft (60) in the rotational direction is less likely to break.

[0081] In the eighth embodiment of the power tool (1), in any of the first to seventh embodiments, the output shaft (60) has one or more second teeth (62) that mesh in the rotational direction with one or more first teeth (54) provided on the anvil (50). The meshing of the one or more first teeth (54) and the one or more second teeth (62) causes the output shaft (60) and the anvil (50) to engage in the rotational direction.

[0082] According to this embodiment, the output shaft (60) and the anvil (50) can be reliably engaged in the rotational direction.

[0083] The configurations relating to the second to eighth aspects are not essential to the power tool (1) and can be omitted as appropriate. [Explanation of symbols]

[0084] 1 Power tools 10 Housing 20 motors 21 Motor shaft 30 Drive shaft 31 Drive Member 32 Shaft component 40 Hammer 50 Anvil 54 First tooth 60 Output shaft 62 Second tooth 70 Bearing section 80 Cushioning material 91 First Movement Control Unit 92 Second Movement Control Section B1 Tip tool GP1 gap

Claims

1. A drive shaft that rotates in accordance with the rotation of the motor shaft, A hammer that rotates by receiving rotational force from the aforementioned drive shaft, The anvil rotates as it is struck by the hammer as the hammer rotates, An output shaft to which a cutting tool can be attached, which engages with the anvil in the rotational direction and rotates in accordance with the rotation of the anvil, The device comprises a housing that covers at least the hammer and the anvil and supports the output shaft via a bearing portion, The output shaft has one or more second teeth that mesh in the rotational direction with one or more first teeth provided on the anvil, The one or more first teeth and the one or more second teeth mesh together, causing the output shaft and the anvil to engage in the rotational direction. The drive shaft is provided so as to be rotatable relative to the output shaft. A damping member is provided between the drive shaft and the output shaft to reduce axial vibrations transmitted between the output shaft and the drive shaft. In the axial direction, the cushioning member provided between the drive shaft and the output shaft restricts the output shaft from moving toward the drive shaft, so that when the output shaft and the anvil are engaged in the rotational direction, a gap is provided between the one or more first teeth and the output shaft in the axial direction, and a gap is provided between the one or more second teeth and the anvil in the axial direction. The aforementioned drive shaft, A drive member that rotates in accordance with the rotation of the motor shaft and transmits rotational force to the hammer, The shaft member is disposed between the cushioning member and the drive member, The shaft member is capable of contacting the cushioning member, The drive member is provided so as to be rotatable relative to the shaft member. Power tools.

2. A drive shaft that rotates in accordance with the rotation of the motor shaft of the motor, A hammer that rotates by receiving rotational force from the aforementioned drive shaft, The anvil rotates as it is struck by the hammer as the hammer rotates, An output shaft to which a cutting tool can be attached, which engages with the anvil in the rotational direction and rotates in accordance with the rotation of the anvil, The device comprises a housing that covers at least the hammer and the anvil and supports the output shaft via a bearing portion, The output shaft has one or more second teeth that mesh in the rotational direction with one or more first teeth provided on the anvil, The one or more first teeth and the one or more second teeth mesh together, causing the output shaft and the anvil to engage in the rotational direction. The drive shaft is provided so as to be rotatable relative to the output shaft. A damping member is provided between the drive shaft and the output shaft to reduce axial vibrations transmitted between the output shaft and the drive shaft. In the axial direction, the cushioning member provided between the drive shaft and the output shaft restricts the output shaft from moving toward the drive shaft, so that when the output shaft and the anvil are engaged in the rotational direction, a gap is provided in the axial direction between the one or more first teeth and the output shaft without any other members intervening, and a gap is provided in the axial direction between the one or more second teeth and the anvil without any other members intervening. Power tools.

3. The drive shaft is A drive member that rotates in accordance with the rotation of the motor shaft and transmits rotational force to the hammer, The shaft member is disposed between the cushioning member and the drive member, The shaft member is capable of contacting the cushioning member, The drive member is provided so as to be rotatable relative to the shaft member. The power tool according to claim 2.

4. The cushioning member is made of an elastic material, The power tool according to claim 1 or 2.

5. The anvil further comprises a first movement restricting portion that restricts the anvil from moving away from the hammer in the axial direction, The power tool according to claim 1 or 2.

6. The first movement restricting part is provided in the housing, The first movement restricting portion is made of an elastic material. The power tool according to claim 5.

7. The output shaft further comprises a second movement restricting unit that restricts the output shaft from moving away from the anvil in the axial direction, The power tool according to claim 1 or 2.

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