Impact tool

Abstract

To provide an impact tool that can smoothly execute each of high-load work and low-load work.SOLUTION: An impact tool is equipped with a motor, a spindle that has a spindle shaft portion and a flange portion provided at a rear part of the spindle shaft portion, and is rotated by the rotational force of the motor, a tool holding shaft that is at least partially disposed ahead of the spindle, a hammer that is supported by the spindle shaft and strikes the tool holding shaft in a rotating direction, and an elastic member that is disposed between a front surface of the flange portion and a supporting surface of the hammer disposed ahead of the flange portion in an axial direction, and an elastic force adjusting mechanism that adjusts the elastic force of the elastic member in an initial state before the motor starts.SELECTED DRAWING: Figure 5

Description

Technical Field

[0006] , , ,

[0005] , ,

[0001] The technology disclosed in this specification relates to impact tools.

Background Art

[0002] In the technical field related to impact tools, impact tools such as those disclosed in Patent Document 1 are known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An impact tool includes a hammer that strikes an anvil in a rotational direction. The hammer is biased forward by an elastic member such as a coil spring. For example, in a screw tightening operation, when the load applied to the anvil increases, the hammer moves backward against the elastic force (biasing force) of the elastic member and rotates while moving forward based on the elastic force of the elastic member. In a low - load operation where the load applied to the anvil is low, if an elastic member with a high elastic force is used, it may be difficult to smoothly perform the screw tightening operation. Similarly, in a high - load operation where the load applied to the anvil is high, if an elastic member with a low elastic force is used, it may be difficult to smoothly perform the screw tightening operation.

[0005] The technology disclosed in this specification aims to provide an impact tool that can smoothly perform each of high - load operations and low - load operations.

Means for Solving the Problems

[0007] The technology disclosed herein provides an impact tool that can smoothly perform both high-load and low-load tasks. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a front perspective view showing an impact tool according to the first embodiment. [Figure 2] Figure 2 is a side view showing an impact tool according to the first embodiment. [Figure 3] Figure 3 is a cross-sectional view showing an impact tool according to the first embodiment. [Figure 4] Figure 4 is a front perspective view showing the output assembly according to the first embodiment. [Figure 5] Figure 5 is a longitudinal cross-sectional view showing the output assembly according to the first embodiment. [Figure 6] Figure 6 is a cross-sectional view showing the output assembly according to the first embodiment. [Figure 7] Figure 7 is a cross-sectional view showing the output assembly according to the first embodiment. [Figure 8] Figure 8 is a cross-sectional view showing the output assembly according to the first embodiment. [Figure 9] Figure 9 is a cross-sectional view showing the output assembly according to the first embodiment. [Figure 10]FIG. 10 is a cross-sectional view showing the output assembly according to the first embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing the output assembly according to the first embodiment. [Figure 12] FIG. 12 is an exploded perspective view showing the output assembly according to the first embodiment. [Figure 13] FIG. 13 is an exploded perspective view from the front showing the main part of the output assembly according to the first embodiment. [Figure 14] FIG. 14 is an exploded perspective view from the rear showing the main part of the output assembly according to the first embodiment. [Figure 15] FIG. 15 is a perspective view from the front showing the spindle according to the first embodiment. [[ID=十六]] [Figure 16] FIG. 16 is a side view showing the spindle according to the first embodiment. [Figure 17] FIG. 17 is a view of the spindle according to the first embodiment seen from the front. [Figure 18] FIG. 18 is a perspective view from the front showing the cam ring according to the first embodiment. [Figure 19] FIG. 19 is a view of the cam ring according to the first embodiment seen from the rear. [Figure 20] FIG. 20 is a cross-sectional view showing the cam ring according to the first embodiment. [Figure 21] FIG. 21 is a perspective view from the front showing the tool holding shaft according to the first embodiment. [Figure 22] FIG. 22 is a cross-sectional view showing the tool holding shaft according to the first embodiment. [Figure 23] FIG. 23 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 24] FIG. 24 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 25] FIG. 25 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 26] FIG. 26 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [[ID=四十九]] [Figure 27] Figure 27 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 28] Figure 28 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 29] Figure 29 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 30] Figure 30 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 31] Figure 31 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 32] Figure 32 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 33] Figure 33 is a front perspective view showing a part of the impact tool according to the second embodiment. [Figure 34] Figure 34 is a front perspective view showing the output assembly according to the second embodiment. [Figure 35] Figure 35 is a longitudinal cross-sectional view showing the output assembly according to the second embodiment. [Figure 36] Figure 36 is an exploded perspective view showing the output assembly according to the second embodiment. [Figure 37] Figure 37 is a front perspective view showing a part of the impact tool according to the third embodiment. [Figure 38] Figure 38 is a longitudinal cross-sectional view showing a part of the impact tool according to the third embodiment. [Figure 39] Figure 39 is a transverse cross-sectional view showing a part of the impact tool according to the third embodiment. <� [Figure 40] Figure 40 is a cross-sectional view showing a part of the impact tool according to the third embodiment. [Figure 41] Figure 41 is a cross-sectional view showing a part of the impact tool according to the third embodiment. [Figure 42] Figure 42 is a cross-sectional view showing a part of the impact tool according to the third embodiment. [Figure 43]Figure 43 is a cross-sectional view showing a part of an impact tool according to the third embodiment. [Figure 44] Figure 44 is a cross-sectional view showing a part of an impact tool according to the third embodiment. [Figure 45] Figure 45 is a view from above of a part of an impact tool according to the third embodiment. [Figure 46] Figure 46 is a front perspective view showing a portion of the output assembly according to the fourth embodiment. [Figure 47] Figure 47 is a longitudinal cross-sectional view showing the output assembly according to the fourth embodiment. [Figure 48] Figure 48 is a cross-sectional view showing a portion of the output assembly according to the fourth embodiment. [Figure 49] Figure 49 is a cross-sectional view showing a portion of the output assembly according to the fourth embodiment. [Modes for carrying out the invention]

[0009] In one or more embodiments, the impact tool may include a motor, a spindle having a spindle shaft portion and a flange portion provided at the rear of the spindle shaft portion and rotating by the rotational force of the motor, a tool holding shaft having at least a portion positioned in front of the spindle, a hammer supported on the spindle shaft portion and striking the tool holding shaft in the rotational direction, an elastic member positioned in the axial direction between the front surface of the flange portion and the support surface of the hammer positioned in front of the flange portion, and an elastic force adjustment mechanism for adjusting the elastic force of the elastic member in an initial state before the motor is started.

[0010] In the above configuration, since the elastic force of the elastic member is adjustable, the impact tool can smoothly perform both high-load and low-load tasks. When low-load tasks are performed, the elastic force of the elastic member is adjusted to be low, and when high-load tasks are performed, the elastic force of the elastic member is adjusted to be high, thereby enabling the impact tool to smoothly perform both high-load and low-load tasks.

[0011] In one or more embodiments, the elastic force adjustment mechanism may adjust the amount of compression of the elastic member in the initial state.

[0012] In the above configuration, the elastic force of the elastic member is adjusted by adjusting the amount of compression of the elastic member in the initial state. When the amount of compression is small, the elastic force of the elastic member becomes low, and when the amount of compression is large, the elastic force of the elastic member becomes high.

[0013] In one or more embodiments, the rear end of the elastic member may be supported by the flange portion. The elastic force adjustment mechanism may adjust the amount of compression by moving the position of the front end of the elastic member.

[0014] In the above configuration, the compression amount is adjusted by moving the position of the front end of the elastic member while the position of the rear end of the elastic member is fixed.

[0015] In one or more embodiments, the elastic force adjustment mechanism may have a screw located in a threaded hole formed in the hammer and connected to the front end of the elastic member. The amount of compression may be adjusted by rotating the screw.

[0016] In the above configuration, the amount of compression is adjusted because the screw moves in the front-to-back direction when it is rotated while positioned in the screw hole.

[0017] In one or more embodiments, the impact tool may include a washer supporting the front end of the elastic member. The rear end of the screw may be in contact with the front surface of the washer. The screw may be connected to the elastic member via the washer.

[0018] In the above configuration, the front end of the elastic member moves smoothly.

[0019] In one or more embodiments, multiple screw holes may be formed at intervals around the rotation axis of the hammer. One screw may be placed in each of the multiple screw holes.

[0020] In the above configuration, the compression amount of the elastic member is adjusted by adjusting the position of each of the multiple screws in the front-rear direction, and the inclination angle of the elastic member with respect to the spindle is also adjusted. The inclination angle of the elastic member with respect to the spindle refers to the angle between the rotation axis of the spindle and the rotation axis (central axis) of the elastic member.

[0021] In one or more embodiments, the hammer may have an inner cylinder portion arranged around the spindle shaft portion, a front outer cylinder portion arranged radially outward and forward of the inner cylinder portion, and a rear outer cylinder portion arranged radially outward of the front outer cylinder portion and rearward of the front outer cylinder portion. The screw holes may be formed to penetrate the front end surface and support surface of the rear outer cylinder portion.

[0022] In the above configuration, the assembler or operator of the impact tool can smoothly bring the screw tightening tool into contact with the screw positioned in the screw hole, and rotate the screw smoothly.

[0023] In one or more embodiments, the impact tool may include a hammer case for housing a hammer, and a hammer bearing held in the hammer case and rotatably supporting the hammer. The hammer bearing may be arranged around the front outer cylinder portion.

[0024] In the above configuration, after the adjustment of the elastic force by the screw is complete, the hammer bearing is positioned to cover the front end of the screw hole. This protects the screw with the hammer bearing.

[0025] In one or more embodiments, the impact tool may include a hammer case for housing a hammer. The hammer case may have through holes that overlap with the screw holes in the radial and circumferential directions, respectively. The screw may rotate through the through holes.

[0026] In the above configuration, the worker can smoothly bring the screw tightening tool into contact with the screw positioned in the screw hole through the through-hole, and rotate the screw smoothly. The worker can adjust the elastic force of the elastic member as appropriate according to the work being done.

[0027] In one or more embodiments, the impact tool may include a hammer bearing that is held in a hammer case and rotatably supports the hammer. The hammer bearing may be positioned around the rear outer cylinder portion.

[0028] In the above configuration, since the front end of the screw hole is not covered by the hammer bearing, the worker can smoothly bring the screw tightening tool into contact with the screw positioned in the screw hole through the through hole, and rotate the screw smoothly.

[0029] In one or more embodiments, the impact tool may include a bearing box for holding a spindle and a hammer case for holding a hammer. The hammer case may be coupled to the bearing box via a threaded portion. The elastic force of the elastic member may be adjusted by rotating the hammer case relative to the bearing box and moving it axially.

[0030] In the above configuration, the operator can adjust the elastic force of the elastic member by grasping the hammer case by hand and rotating it. The operator can adjust the elastic force of the elastic member without using a screw tightening tool.

[0031] In one or more embodiments, the impact tool may include a motor housing for housing a motor, and a first anti-rotation mechanism for suppressing relative rotation between the motor housing and the bearing box.

[0032] In the above configuration, when the hammer case is rotated, the first anti-rotation mechanism suppresses the rotation of the bearing box, allowing the operator to smoothly rotate the hammer case relative to the bearing box.

[0033] In one or more embodiments, the impact tool may include a cover that encloses the hammer case, and a second anti-rotation mechanism that restricts relative rotation between the cover and the hammer case. The hammer case may rotate via the cover.

[0034] In the above configuration, the second anti-rotation mechanism suppresses relative rotation between the cover and the hammer case, allowing the operator to rotate the hammer case by grasping and rotating the cover with their hand. The rotation of the hammer case adjusts the elastic force of the elastic member. The operator can adjust the elastic force of the elastic member without directly touching the hammer case.

[0035] In one or more embodiments, the impact tool may include a positioning mechanism for positioning the cover in the circumferential direction.

[0036] In the above configuration, unnecessary rotation of the hammer case and cover is suppressed.

[0037] In one or more embodiments, the elastic member may include a disc spring.

[0038] In the above configuration, the size of the impact tool is suppressed. When a predetermined elastic force is required for the elastic member, using a disc spring allows for a shorter axial dimension of the elastic member compared to, for example, using a coil spring. This allows the hammer to strike the tool holding shaft in the rotational direction while suppressing the size of the impact tool. In particular, the axial length of the impact tool is shortened. When the impact tool has a motor housing, a rear cover located at the rear end of the motor housing, and an output assembly located at the front of the motor housing, the axial length of the impact tool refers to the axial distance between the rear end of the rear cover and the front end of the output assembly.

[0039] In one or more embodiments, the impact tool may include a washer supporting the front end of the elastic member. The front end of the elastic member may be connected to the hammer via the washer.

[0040] In the above configuration, the front end of the elastic member is stably connected to the hammer via a washer.

[0041] In one or more embodiments, the impact tool may include a movable anvil movably supported on a tool-holding shaft. The hammer may strike the movable anvil in a rotational direction without axial displacement.

[0042] In the above configuration, a movable anvil is provided that is movably supported on the tool holding shaft, so that the hammer can strike the movable anvil in the rotational direction without axial displacement. Since the hammer does not axially displace, the generation of axial vibration in the impact tool is suppressed.

[0043] In one or more embodiments, the movable anvil may move to change between a first state in which at least a portion of the movable anvil protrudes radially outward from the outer surface of the tool-holding shaft, and a second state in which the movable anvil is positioned radially inward from the outer surface of the tool-holding shaft. The hammer may strike the movable anvil in the first state and rotate around the spindle shaft portion in the second state.

[0044] In the above configuration, the hammer can strike the movable anvil in the rotational direction without being displaced in the axial direction.

[0045] In one or more embodiments, the impact tool may include a cam ring connected to the flange portion via a ball so as to be rotatable relative to it, and connected to the hammer so as to be axially movable and not rotatable relative to it. The cam ring may be positioned opposite the front surface of the flange portion. The elastic member may be positioned axially between the front surface of the cam ring and the support surface of the hammer.

[0046] In the above configuration, the cam ring is connected to the flange portion of the spindle via a ball so as to be rotatable relative to it. The cam ring is also connected to the hammer so as to be axially movable but not rotatable relative to it. This allows the hammer to strike the tool holding shaft in the rotational direction while the shaft length is shortened.

[0047] In one or more embodiments, the cam ring may be connected to the rear of the hammer. The elastic member may be located in a closed space defined by the spindle shaft, the hammer, and the cam ring.

[0048] In the above configuration, when the hammer strikes the tool-holding shaft in the rotational direction via the movable anvil, the cam ring and elastic member also rotate together with the hammer. That is, when the hammer strikes the tool-holding shaft, not only the moment of inertia of the hammer, but also the moment of inertia of the cam ring and the moment of inertia of the elastic member are applied to the tool-holding shaft. As a result, the tool-holding shaft is struck with a high impact force.

[0049] The embodiments will be described below with reference to the drawings. The components of the embodiments described below can be combined as appropriate. In addition, some components may be omitted.

[0050] In the embodiments, the positional relationships of each part will be described using the terms left, right, front, rear, top, and bottom. These terms indicate relative positions or directions with respect to the center of the impact tool. The impact tool has a motor 6 as its power source.

[0051] In this embodiment, the direction parallel to the rotation axis AX of the motor 6 is appropriately referred to as the axial direction, the direction that circles around the rotation axis AX is appropriately referred to as the circumferential direction or rotational direction, and the radial direction of the rotation axis AX is appropriately referred to as the radial direction.

[0052] In the axial direction, the direction or position away from the center of the impact tool in a specified direction shall be appropriately referred to as the "one axial side," and the opposite side of the "one axial side" shall be appropriately referred to as the "other axial side." In the circumferential direction, the specified direction shall be appropriately referred to as the "one circumferential side," and the opposite side of the "one circumferential side" shall be appropriately referred to as the "other circumferential side." In the radial direction, the direction or position away from the rotation axis AX shall be appropriately referred to as the "radial outward side," and the opposite side of the "radial outward side" shall be appropriately referred to as the "radial inward side."

[0053] In this embodiment, the axial direction and the front-rear direction coincide. One side of the axial direction may be considered the front. The other side of the axial direction may be considered the rear.

[0054] [First Embodiment] The first embodiment will be described.

[0055] <Overview of impact tools> Figure 1 is a front perspective view showing the impact tool 1 according to this embodiment. Figure 2 is a side view showing the impact tool 1 according to this embodiment. Figure 3 is a cross-sectional view showing the impact tool 1 according to this embodiment.

[0056] In this embodiment, the impact tool 1 is an impact driver, which is a type of screw tightening tool. The impact tool 1 comprises a housing 2, a rear cover 3, an output assembly 4, a battery mounting section 5, a motor 6, a fan 7, a controller 8, a trigger lever 9, a forward / reverse rotation switch 10, an interface section 11, a mode switch 12, and a light 13.

[0057] The housing 2 houses at least some of the components of the impact tool 1. The housing 2 is made of synthetic resin. In this embodiment, the housing 2 is made of nylon. The housing 2 consists of a pair of split housings. The housing 2 includes a left housing 14 and a right housing 15 positioned to the right of the left housing 14. The left housing 14 and the right housing 15 are fastened together by a plurality of housing screws 16.

[0058] The housing 2 has a motor housing section 17, a grip section 18, and a battery holding section 19.

[0059] The motor housing 17 houses the motor 6. The motor housing 17 houses at least a portion of the output assembly 4. The motor housing 17 is cylindrical.

[0060] The grip portion 18 is held by the operator. The grip portion 18 extends downward from the motor housing portion 17.

[0061] The battery holder 19 holds the battery pack 20 via the battery mounting section 5. The battery holder 19 houses the controller 8. The battery holder 19 is connected to the lower end of the grip section 18.

[0062] The rear cover 3 covers the opening at the rear end of the motor housing 17. The rear cover 3 is positioned behind the motor housing 17. The rear cover 3 is made of synthetic resin. The rear cover 3 is secured to the rear end of the motor housing 17 by two screws. The rear cover 3 houses at least a portion of the fan 7.

[0063] The motor housing 17 has an air intake port 21. The rear cover 3 has an exhaust port 22. Air from the external space of the housing 2 flows into the internal space of the housing 2 through the air intake port 21. Air from the internal space of the housing 2 flows out into the external space of the housing 2 through the exhaust port 22.

[0064] The output assembly 4 is positioned in front of the motor 6. The output assembly 4 includes a hammer case 23, a bearing box 24, a reduction mechanism 25, a spindle 26, a spindle bearing 27, a striking mechanism 28, an elastic force adjustment mechanism 29, a hammer bearing 30, a tool holding shaft 31, a shaft bearing 32, a movable anvil 33, and a tool holding mechanism 34.

[0065] The hammer case 23 is made of metal. In this embodiment, the hammer case 23 is made of aluminum. At least a portion of the hammer case 23 is positioned in front of the motor housing 17. The hammer case 23 is cylindrical. The bearing box 24 is fixed to the rear end of the hammer case 23. The rear of the bearing box 24 and the hammer case 23 are positioned inside the motor housing 17. The rear of the bearing box 24 and the hammer case 23 are sandwiched between the left housing 14 and the right housing 15. Each of the bearing box 24 and the hammer case 23 is fixed to the motor housing 17.

[0066] The reduction gear 25, spindle 26, striking mechanism 28, movable anvil 33, spindle bearing 27, hammer bearing 30, and shaft bearing 32 are located in the internal space of the output assembly 4, which is defined by the hammer case 23 and the bearing box 24. At least a portion of the tool holding shaft 31 is located in the internal space of the output assembly 4.

[0067] A battery pack 20 is mounted in the battery mounting section 5. The battery mounting section 5 is located below the battery holder 19. The battery pack 20 is detachable from the battery mounting section 5. The battery pack 20 functions as a power source for the impact tool 1. The battery pack 20 is mounted in the battery mounting section 5 by being inserted into the battery mounting section 5 from the front of the battery holder 19. The battery pack 20 is removed from the battery mounting section 5 by being pulled forward from the battery mounting section 5. The battery pack 20 includes a secondary battery. In this embodiment, the battery pack 20 includes a rechargeable lithium-ion battery. By being mounted in the battery mounting section 5, the battery pack 20 can supply power to the impact tool 1. The motor 6 is driven based on the power supplied from the battery pack 20. The controller 8 and the interface section 11 each operate based on the power supplied from the battery pack 20.

[0068] Motor 6 is the power source for the impact tool 1. Motor 6 is an electric motor driven by power supplied from the battery pack 20. Motor 6 is an inner rotor type brushless motor. Motor 6 has a stator 35 and a rotor 36. The stator 35 is supported by the motor housing 17. At least a portion of the rotor 36 is located inside the stator 35. The rotor 36 rotates relative to the stator 35. The rotor 36 rotates around a rotation axis AX that extends in the front-rear direction.

[0069] The stator 35 includes a stator core 37, a front insulator 38, a rear insulator 39, and a coil 40.

[0070] The stator core 37 is positioned radially outward from the rotor 36. The stator core 37 includes multiple laminated steel plates. The steel plates are metal plates mainly composed of iron. The stator core 37 is cylindrical. The stator core 37 has multiple teeth that support the coil 40.

[0071] The front insulator 38 is fixed to the front of the stator core 37. The rear insulator 39 is fixed to the rear of the stator core 37. Both the front insulator 38 and the rear insulator 39 are electrically insulating members made of synthetic resin. The front insulator 38 is positioned to cover a portion of the surface of the teeth. The rear insulator 39 is positioned to cover a portion of the surface of the teeth.

[0072] The coil 40 is mounted on the stator core 37 via a front insulator 38 and a rear insulator 39. Multiple coils 40 are arranged. The coils 40 are arranged around the teeth of the stator core 37 via the front insulator 38 and the rear insulator 39. The coils 40 and the stator core 37 are electrically insulated by the front insulator 38 and the rear insulator 39. Multiple coils 40 are interconnected via short-circuiting members.

[0073] The rotor 36 rotates around the rotation axis AX. The rotor 36 includes a rotor core 41, a rotor shaft 42, a rotor magnet 43, and a sensor magnet 44.

[0074] The rotor core 41 and rotor shaft 42 are both made of steel. The rotor shaft 42 is fixed to the rotor core 41. The rotor core 41 is cylindrical. The rotor shaft 42 is positioned radially inward from the rotor core 41. The front part of the rotor shaft 42 protrudes forward from the front end face of the rotor core 41. The rear part of the rotor shaft 42 protrudes rearward from the rear end face of the rotor core 41.

[0075] The rotor magnet 43 is fixed to the rotor core 41. The rotor magnet 43 is cylindrical. The rotor magnet 43 is arranged around the rotor core 41.

[0076] The sensor magnet 44 is fixed to the rotor core 41. The sensor magnet 44 is annular in shape. The sensor magnet 44 is positioned on the front end surface of the rotor core 41 and the front end surface of the rotor magnet 43.

[0077] A sensor board 45 is attached to the front insulator 38. The sensor board 45 is fixed to the front insulator 38 by screws. The sensor board 45 has an annular circuit board and a magnetic sensor supported by the circuit board. At least a portion of the sensor board 45 faces the sensor magnet 44. The magnetic sensor detects the rotational position of the rotor 36 by detecting the position of the sensor magnet 44.

[0078] The rear of the rotor shaft 42 is rotatably supported by a rotor bearing 46. The front of the rotor shaft 42 is rotatably supported by a rotor bearing 47. The rotor bearing 46 is held in the rear cover 3. The rotor bearing 46 is held in the bearing box 24. The front end of the rotor shaft 42 is positioned in the internal space of the output assembly 4 through an opening in the bearing box 24.

[0079] A pinion gear 48 is fixed to the front end of the rotor shaft 42. The pinion gear 48 is connected to at least a portion of the reduction mechanism 25. The rotor shaft 42 is connected to the reduction mechanism 25 via the pinion gear 48.

[0080] Fan 7 generates airflow to cool the motor 6. Fan 7 is positioned behind the motor 6. Fan 7 is positioned between the rotor bearing 46 and the stator 35. Fan 7 is fixed to at least a portion of the rotor 36. Fan 7 is fixed to the rear of the rotor shaft 42 via bushings 49. Fan 7 rotates with the rotation of the rotor 36. As the rotor shaft 42 rotates, fan 7 rotates together with the rotor shaft 42. The rotation of fan 7 causes air from the external space of housing 2 to flow into the internal space of housing 2 through the intake port 21. The air that flows into the internal space of housing 2 cools the motor 6 by circulating through the internal space of housing 2. The air that has circulated through the internal space of housing 2 flows out into the external space of housing 2 through the exhaust port 22 due to the rotation of fan 7.

[0081] The controller 8 outputs control signals to control the motor 6. The controller 8 is housed in the battery holder 19. The controller 8 switches the control mode of the motor 6 based on the work performed by the impact tool 1. The control mode of the motor 6 refers to the control method or control pattern of the motor 6. The controller 8 includes a circuit board 50 on which multiple electronic components are mounted, and a case 51 that houses the circuit board 50. Examples of electronic components mounted on the circuit board 50 include a processor such as a CPU (Central Processing Unit), non-volatile memory such as ROM (Read Only Memory) or storage, volatile memory such as RAM (Random Access Memory), transistors, and resistors.

[0082] The trigger lever 9 is operated by the operator to start the motor 6. The trigger lever 9 is located on the grip portion 18. The trigger lever 9 protrudes forward from the upper front part of the grip portion 18. By operating the trigger lever 9, the motor 6 is switched between running and stopping.

[0083] The forward / reverse rotation selector lever 10 is operated by the operator to switch the rotation direction of the motor 6. The forward / reverse rotation selector lever 10 is located on the upper part of the grip section 18. When the forward / reverse rotation selector lever 10 is operated, the rotation direction of the motor 6 is switched from one direction to the other. Switching the rotation direction of the motor 6 switches the rotation direction of the spindle 26. When the forward / reverse rotation selector lever 10 is in the neutral position, the trigger lever 9 cannot be operated.

[0084] The interface unit 11 has a number of operation buttons 52 that are operated by the operator. The interface unit 11 is located on the battery holder 19. The interface unit 11 is located on the upper surface of the battery holder 19, in front of the grip unit 18. The operation mode of the motor 6 is switched when the operator operates the operation buttons 52.

[0085] The mode selector switch 12 is operated by the operator to switch the control mode of the motor 6. The mode selector switch 12 is located above the trigger lever 9.

[0086] Light 13 emits illumination light. Light 13 illuminates the area around the tool holding shaft 31 and the area in front of the tool holding shaft 31 with illumination light.

[0087] <Output Assembly> Figure 4 is a front perspective view showing the output assembly 4 according to this embodiment. Figure 5 is a longitudinal cross-sectional view showing the output assembly 4 according to this embodiment. Figure 6 is a transverse cross-sectional view showing the output assembly 4 according to this embodiment. Figure 7 is a cross-sectional view showing the output assembly 4 according to this embodiment, corresponding to the view taken along line CC in Figure 5. Figure 8 is a cross-sectional view showing the output assembly 4 according to this embodiment, corresponding to the view taken along line DD in Figure 5. Figure 9 is a cross-sectional view showing the output assembly 4 according to this embodiment, corresponding to the view taken along line EE in Figure 5. Figure 10 is a cross-sectional view showing the output assembly 4 according to this embodiment, corresponding to the view taken along line FF in Figure 5. Figure 11 is a cross-sectional view showing the output assembly 4 according to this embodiment, corresponding to the view taken along line GG in Figure 5. Figure 12 is an exploded perspective view showing the output assembly 4 according to this embodiment.

[0088] The output assembly 4 includes a hammer case 23, a bearing box 24, a reduction mechanism 25, a spindle 26, a spindle bearing 27, a striking mechanism 28, an elastic force adjustment mechanism 29, a hammer bearing 30, a tool holding shaft 31, a shaft bearing 32, a movable anvil 33, and a tool holding mechanism 34.

[0089] The rotor 36, spindle 26, and tool holding shaft 31 each rotate around the rotation axis AX. The rotation axis of the rotor 36, the rotation axis of the spindle 26, and the rotation axis of the tool holding shaft 31 coincide. The spindle 26 and the tool holding shaft 31 each rotate due to the rotational force generated by the motor 6.

[0090] (Hammer case) The hammer case 23 has a large cylindrical section 53 and a small cylindrical section 54. The large cylindrical section 53 and the small cylindrical section 54 are arranged to surround the rotation axis AX. The small cylindrical section 54 is positioned in front of the large cylindrical section 53. The inner diameter of the large cylindrical section 53 is larger than the inner diameter of the small cylindrical section 54. The outer diameter of the large cylindrical section 53 is larger than the outer diameter of the small cylindrical section 54.

[0091] The bearing box 24 is fixed to the rear end of the hammer case 23. The bearing box 24 has a ring portion 55, a rear plate portion 56, and a protrusion portion 57. The ring portion 55 is arranged to surround the rotating shaft AX. The ring portion 55 is inserted inside the rear end of the large cylindrical portion 53. The rear plate portion 56 is connected to the rear end of the ring portion 55. An opening is provided in the center of the rear plate portion 56. The protrusion portion 57 is provided on the rear surface of the rear plate portion 56. The protrusion portion 57 projects rearward from the rear surface of the rear plate portion 56. The protrusion portion 57 is arranged to surround the opening of the rear plate portion 56. The rear plate portion 56 and the protrusion portion 57 are each connected to the motor housing portion 17.

[0092] (Deceleration mechanism) The reduction gear 25 connects the rotor shaft 42 and the spindle 26. The reduction gear 25 transmits the rotation of the rotor 36 to the spindle 26. The reduction gear 25 rotates the spindle 26 at a rotational speed lower than the rotational speed of the rotor shaft 42. The reduction gear 25 includes a planetary gear mechanism.

[0093] The reduction mechanism 25 includes a plurality of planetary gears 58 arranged around a pinion gear 48, pins 59 supporting each of the plurality of planetary gears 58, and an internal gear 60 arranged around the plurality of planetary gears 58. Each of the plurality of planetary gears 58 meshes with the pinion gear 48. The planetary gears 58 are rotatably supported on the spindle 26 via the pins 59. The spindle 26 is rotated by the planetary gears 58. The internal gear 60 has internal teeth that mesh with the planetary gears 58.

[0094] The internal gear 60 is fixed to the hammer case 23 and the bearing box 24, respectively. An O-ring 61 is placed at the boundary between the rear end of the internal gear 60 and the bearing box 24. A protrusion 62 is provided on the outer surface of the internal gear 60. The protrusion 62 projects radially outward from the outer circumferential surface of the internal gear 60. Multiple protrusions 62 are provided at intervals in the circumferential direction. The protrusions 62 are positioned in the recesses 63 of the hammer case 23. The positioning of the protrusions 62 in the recesses 63 suppresses relative rotation between the hammer case 23 and the internal gear 60. The internal gear 60 is always unable to rotate relative to the hammer case 23.

[0095] When the rotor shaft 42 rotates due to the drive of the motor 6, the pinion gear 48 rotates, and the planetary gear 58 revolves around the pinion gear 48. The planetary gear 58 revolves while meshing with the internal teeth of the internal gear 60. Due to the revolving of the planetary gear 58, the spindle 26, which is connected to the planetary gear 58 via the pin 59, rotates at a lower rotational speed than the rotational speed of the rotor shaft 42.

[0096] (Spindle) Figure 13 is an exploded front perspective view showing the main parts of the output assembly 4 according to this embodiment. Figure 14 is an exploded rear perspective view showing the main parts of the output assembly 4 according to this embodiment. Figure 15 is a front perspective view showing the spindle 26 according to this embodiment. Figure 16 is a side view showing the spindle 26 according to this embodiment. Figure 17 is a front view of the spindle 26 according to this embodiment.

[0097] The spindle 26 rotates due to the rotational force of the motor 6. At least a portion of the spindle 26 is positioned in front of the reduction mechanism 25. The spindle 26 is positioned behind the tool holding shaft 31. The spindle 26 rotates due to the rotor 36. The spindle 26 rotates due to the rotational force of the rotor 36 transmitted by the reduction mechanism 25. The spindle 26 transmits the rotational force of the motor 6 to the movable anvil 33 via the impact mechanism 28.

[0098] The spindle 26 has a spindle shaft portion 64, a flange portion 65, a pin support portion 66, a connecting portion 67, and a protrusion portion 68.

[0099] The spindle shaft portion 64 extends in the axial direction. The spindle shaft portion 64 is arranged to surround the rotation axis AX. A spindle projection 69 is provided at the front end of the outer circumferential surface of the spindle shaft portion 64. The spindle projection 69 protrudes radially outward from the front end of the outer circumferential surface of the spindle shaft portion 64. Two spindle projections 69 are provided around the rotation axis AX. The two spindle projections 69 are arranged to sandwich the rotation axis AX. In the following description, one of the spindle projections 69 will be appropriately referred to as the first spindle projection 691, and the other spindle projection 69 will be appropriately referred to as the second spindle projection 692.

[0100] A ball groove 70 is formed on the outer circumferential surface of the spindle shaft portion 64. The ball groove 70 is positioned behind the spindle projection 69. The ball groove 70 is formed to surround the rotation axis AX. The ball groove 70 is formed to be recessed radially inward from the outer circumferential surface of the spindle shaft portion 64.

[0101] The flange portion 65 is provided at the rear of the spindle shaft portion 64. The flange portion 65 protrudes radially outward from the rear of the spindle shaft portion 64. A spindle groove 71 is provided on the front surface of the flange portion 65. Multiple spindle grooves 71 are provided in the circumferential direction. In this embodiment, three spindle grooves 71 are provided in the circumferential direction.

[0102] The pin support portion 66 is positioned rearward of the flange portion 65. The pin support portion 66 is annular in shape. A portion of the flange portion 65 and a portion of the pin support portion 66 are connected via a connecting portion 67. The protrusion 68 projects rearward from the pin support portion 66.

[0103] The planetary gear 58 is positioned between the flange portion 65 and the pin support portion 66. The front end of the pin 59 is positioned in a support recess 72 provided in the flange portion 65. The rear end of the pin 59 is positioned in a support hole 73 provided in the pin support portion 66. The planetary gear 58 is rotatably supported by the flange portion 65 and the pin support portion 66 via the pin 59.

[0104] The protrusion 68 is positioned inside the spindle bearing 27. The protrusion 68 is rotatably supported by the spindle bearing 27. A washer 74 is positioned opposite the front end of the inner ring of the spindle bearing 27.

[0105] (Striking mechanism) The striking mechanism 28 is driven by the motor 6. The rotational force of the motor 6 is transmitted to the striking mechanism 28 via the reduction mechanism 25 and the spindle 26. The striking mechanism 28 strikes the movable anvil 33 in the rotational direction based on the rotational force of the spindle 26, which is rotated by the motor 6.

[0106] The striking mechanism 28 includes a hammer 75, a cam ring 76, a ball 77, an elastic member 78, a washer 79, and a rotating ball 80.

[0107] The hammer 75 strikes the movable anvil 33 in the rotational direction. The hammer 75 strikes the tool holding shaft 31 in the rotational direction via the movable anvil 33. The hammer 75 is supported by the spindle 26. The hammer 75 is positioned around the spindle shaft portion 64. The hammer 75 is rotatably supported by the spindle shaft portion 64. The hammer 75 is positioned in front of the reduction mechanism 25.

[0108] The hammer 75 does not move axially relative to the hammer case 23. In practice, the hammer 75 may move slightly axially relative to the hammer case 23, for example due to play. The hammer 75 can rotate relative to the spindle 26. The hammer 75 can rotate relative to the spindle shaft portion 64 while being supported by the spindle shaft portion 64. The hammer 75 strikes the movable anvil 33 in the rotational direction without being displaced axially relative to the spindle 26.

[0109] The hammer 75 has a rear outer cylinder portion 81, a front outer cylinder portion 82, and an inner cylinder portion 83. The rear outer cylinder portion 81, the front outer cylinder portion 82, and the inner cylinder portion 83 are each arranged to surround the rotation axis AX. The rear outer cylinder portion 81, the front outer cylinder portion 82, and the inner cylinder portion 83 are integrally formed.

[0110] The front outer cylinder portion 82 is positioned in front of the rear outer cylinder portion 81. The front end of the rear outer cylinder portion 81 is connected to the rear end of the front outer cylinder portion 82. The outer diameter of the rear outer cylinder portion 81 is larger than the outer diameter of the front outer cylinder portion 82. The inner diameter of the rear outer cylinder portion 81 is larger than the inner diameter of the front outer cylinder portion 82.

[0111] The inner cylinder portion 83 is supported by the spindle shaft portion 64. The inner cylinder portion 83 is positioned radially inward from the rear outer cylinder portion 81 and the front outer cylinder portion 82. The front end of the inner cylinder portion 83 is connected to the rear end of the front outer cylinder portion 82. The front outer cylinder portion 82 is positioned radially outward and forward of the inner cylinder portion 83. The rear outer cylinder portion 81 is positioned radially outward from the inner cylinder portion 83 and the front outer cylinder portion 82, and is positioned rearward from the front outer cylinder portion 82.

[0112] A hammer projection 84 is provided on the inner circumferential surface of the front outer cylinder portion 82. The hammer projection 84 protrudes radially inward from the inner circumferential surface of the front outer cylinder portion 82. Two hammer projections 84 are provided around the rotation axis AX. The two hammer projections 84 are arranged so as to sandwich the rotation axis AX. The two hammer projections 84 are arranged so as to face each other. In the following description, one hammer projection 84 will be appropriately referred to as the first hammer projection 841, and the other hammer projection 84 will be appropriately referred to as the second hammer projection 842.

[0113] The inner cylinder portion 83 is positioned around the spindle shaft portion 64. The inner circumferential surface of the inner cylinder portion 83 and the outer circumferential surface of the spindle shaft portion 64 face each other. A ball groove 85 is formed on the inner circumferential surface of the inner cylinder portion 83. The ball groove 85 is formed to surround the rotating shaft AX. The ball groove 85 is formed to be recessed radially outward from the inner circumferential surface of the inner cylinder portion 83.

[0114] Guide grooves 86 are provided on the inner circumferential surface of the rear outer cylinder portion 81. The guide grooves 86 are formed to extend axially on the inner circumferential surface of the rear outer cylinder portion 81. The guide grooves 86 are formed to extend forward from the rear end of the rear outer cylinder portion 81. Multiple guide grooves 86 are provided at intervals around the rotation axis AX of the hammer 75. In this embodiment, six guide grooves 86 are provided around the rotation axis AX. The six guide grooves 86 are provided at equal intervals in the circumferential direction.

[0115] Figure 18 is a front perspective view showing the cam ring 76 according to this embodiment. Figure 19 is a rear view of the cam ring 76 according to this embodiment. Figure 20 is a cross-sectional view showing the cam ring 76 according to this embodiment.

[0116] The cam ring 76 is connected to the flange portion 65 via a ball 77 so as to be rotatable relative to it. The cam ring 76 is connected to the hammer 75 so as to be axially movable but not rotatable relative to it. The cam ring 76 is positioned opposite the front of the flange portion 65. The cam ring 76 is connected to the rear of the hammer.

[0117] The cam ring 76 is positioned inside the rear outer cylinder portion 81. The cam ring 76 and the hammer 75 can move relative to each other in the axial direction. As described above, the hammer 75 does not move axially relative to the hammer case 23. In practice, however, the hammer 75 may move slightly axially relative to the hammer case 23, for example due to play. The cam ring 76 moves axially relative to the hammer case 23 inside the rear outer cylinder portion 81 of the hammer 75.

[0118] A cam slide portion 87 is provided on the outer circumferential surface of the cam ring 76. The cam slide portion 87 protrudes radially outward from the outer circumferential surface of the cam ring 76. Multiple cam slide portions 87 are provided at intervals around the rotation axis AX of the cam ring 76. Six cam slide portions 87 are provided around the rotation axis AX. The six cam slide portions 87 are provided at equal intervals in the circumferential direction. The cam slide portions 87 are positioned in the guide grooves 86. One cam slide portion 87 is positioned in one guide groove 86. The cam slide portion 87 moves axially in the guide grooves 86. The cam ring 76 can move axially relative to the hammer 75 while being guided by the guide grooves 86 via the cam slide portions 87.

[0119] The guide groove 86 of the hammer 75 guides the cam ring 76 in the axial direction and functions as a guide to suppress relative rotation between the hammer 75 and the cam ring 76.

[0120] A cam groove 88 is provided on the inner circumferential surface of the cam ring 76. Multiple cam grooves 88 are provided in the circumferential direction. In this embodiment, three cam grooves 88 are provided in the circumferential direction.

[0121] The cam ring 76 is positioned in front of the flange portion 65. The cam ring 76 is positioned inside the rear outer cylinder portion 81 of the hammer 75, and is positioned facing the front surface of the flange portion 65.

[0122] The ball 77 is positioned between the spindle 26 and the cam ring 76. The ball 77 is positioned between the flange portion 65 and the cam ring 76. The flange portion 65 of the spindle 26 and the cam ring 76 can rotate relative to each other via the ball 77.

[0123] The ball 77 is made of a metal such as steel. The flange portion 65 has a spindle groove 71 in which at least a portion of the ball 77 is positioned. The spindle groove 71 is provided on a part of the front surface of the flange portion 65. In a plane perpendicular to the rotation axis AX, the spindle groove 71 is arc-shaped. The cam ring 76 has a cam groove 88 in which at least a portion of the ball 77 is positioned. The cam groove 88 is provided on a part of the inner circumferential surface of the cam ring 76. In a plane perpendicular to the rotation axis AX, the cam groove 88 is arc-shaped. The ball 77 is positioned between the spindle groove 71 and the cam groove 88. As described above, there are three spindle grooves 71. There are three cam grooves 88. There are three balls 77. One ball 77 is positioned between one spindle groove 71 and one cam groove 88. The ball 77 can roll inside the spindle groove 71 and inside the cam groove 88, respectively. The cam ring 76 is movable along with the ball 77.

[0124] At least a portion of the spindle groove 71 is inclined rearward toward one side in the circumferential direction. At least a portion of the spindle groove 71 may also be inclined rearward toward the other side in the circumferential direction.

[0125] At least a portion of the cam groove 88 is inclined rearward toward one side in the circumferential direction. At least a portion of the cam groove 88 may also be inclined rearward toward the other side in the circumferential direction.

[0126] In this embodiment, each of the multiple spindle grooves 71 has a first portion 711 and a second portion 712. The first portion 711 and the second portion 712 are defined at different positions in the circumferential direction. The boundary between the first portion 711 and the second portion 712 is defined in the central part of the spindle groove 71 in the circumferential direction. The first portion 711 is inclined rearward from the central part of the spindle groove 71 toward one side in the circumferential direction. The second portion 712 is inclined rearward from the central part of the spindle groove 71 toward the other side in the circumferential direction. The first portion 711 is defined between the central part of the spindle groove 71 and one end in the circumferential direction. The second portion 712 is defined between the central part of the spindle groove 71 and the other end in the circumferential direction.

[0127] In this embodiment, each of the multiple cam grooves 88 has a third portion 881 and a fourth portion 882. The third portion 881 and the fourth portion 882 are defined at different positions in the circumferential direction. The boundary between the third portion 881 and the fourth portion 882 is defined in the central part of the cam groove 88 in the circumferential direction. The third portion 881 is inclined rearward from the central part of the cam groove 88 toward one side in the circumferential direction. The fourth portion 882 is inclined rearward from the central part of the cam groove 88 toward the other side in the circumferential direction. The third portion 881 is defined between the central part and one end of the cam groove 88 in the circumferential direction. The fourth portion 882 is defined between the central part and the other end of the cam groove 88 in the circumferential direction.

[0128] During the relative rotation between the flange portion 65 and the cam ring 76, the ball 77 moves the first portion 711 between the first portion 711 of the spindle groove 71 and the third portion 881 of the cam groove 88, from the center of the spindle groove 71 toward one end of the first portion 711 in the circumferential direction. As a result, the cam ring 76 receives force from the ball 77 and moves forward.

[0129] Furthermore, during the relative rotation between the flange portion 65 and the cam ring 76, the ball 77 moves the first portion 711 from one circumferential end toward the center of the spindle groove 71 between the first portion 711 of the spindle groove 71 and the third portion 881 of the cam groove 88, causing the cam ring 76 to receive force from the ball 77 and move backward.

[0130] During the relative rotation between the flange portion 65 and the cam ring 76, the ball 77 moves the second portion 712 between the second portion 712 of the spindle groove 71 and the fourth portion 882 of the cam groove 88, from the center of the spindle groove 71 toward the other circumferential end of the second portion 712. As a result, the cam ring 76 receives force from the ball 77 and moves forward.

[0131] Furthermore, during the relative rotation between the flange portion 65 and the cam ring 76, the ball 77 moves the second portion 712 from the other circumferential end of the second portion 712 toward the center of the spindle groove 71 between the second portion 712 of the spindle groove 71 and the fourth portion 882 of the cam groove 88, causing the cam ring 76 to receive force from the ball 77 and move backward.

[0132] The flange portion 65 of the spindle 26 and the cam ring 76 can move relative to each other in the axial and rotational directions within the range of motion defined by the spindle groove 71 and the cam groove 88.

[0133] The cam ring 76 is connected to the flange portion 65 of the spindle 26 via a ball 77. The cam ring 76 can rotate together with the spindle 26 based on the rotational force of the spindle 26, which is rotated by the motor 6. The cam ring 76 rotates around the rotation axis AX.

[0134] The elastic member 78 constantly generates an elastic force that moves the cam ring 76 backward. In the axial direction, the elastic member 78 is positioned between the hammer 75 and the cam ring 76. At least a portion of the elastic member 78 is positioned around the spindle shaft portion 64. In this embodiment, the hammer 75 has a recess 89 formed to recess forward from the rear surface of the hammer 75. The recess 89 is defined by the inner circumferential surface of the rear outer cylinder portion 81, the outer circumferential surface of the inner cylinder portion 83, and a support surface 90 positioned forward of the flange portion 65 and the cam ring 76. The support surface 90 is positioned to connect the front end of the inner circumferential surface of the rear outer cylinder portion 81 and the front end of the outer circumferential surface of the inner cylinder portion 83. The support surface 90 is annular. At least a portion of the elastic member 78 is positioned inside the recess 89. In the axial direction, the elastic member 78 is positioned between the front surface of the cam ring 76 and the flange portion 65 and the support surface 90 of the hammer 75 which is positioned in front of the cam ring 76.

[0135] In this embodiment, the rear portion of the elastic member 78 is positioned around the spindle shaft portion 64. The front portion of the elastic member 78 is positioned inside the recess 89 around the inner cylinder portion 83. In this embodiment, the elastic member 78 includes a plurality of disc springs 91. The plurality of disc springs 91 are arranged in a plurality in the axial direction. In this embodiment, four disc springs 91 are arranged in the axial direction. The disc springs 91 are annular in shape. In this embodiment, some of the disc springs 91 are positioned around the spindle shaft portion 64, and some of the disc springs 91 are positioned around the inner cylinder portion 83.

[0136] In this embodiment, the spring constant of the elastic member 78 is 100 [N / mm] or more. The upper limit of the spring constant of the elastic member 78 is not particularly limited, but in this embodiment, the spring constant of the elastic member 78 is 10,000 [N / mm] or less.

[0137] The hammer 75 is positioned around the spindle shaft portion 64. The cam ring 76 is positioned in front of the flange portion 65 and is connected to the flange portion 65 via a ball 77. The cam ring 76 is connected to the rear of the hammer 75 via a cam slide portion 87 and a guide groove 86. The spindle shaft portion 64, the hammer 75, and the cam ring 76 define a closed space. The closed space is defined by the outer circumferential surface of the spindle shaft portion 64, the outer circumferential surface of the inner cylinder portion 83, the support surface 90, the inner circumferential surface of the rear outer cylinder portion 81, and the front surface of the cam ring 76. The elastic member 78 is positioned in the closed space.

[0138] The washer 79 supports the front end of the elastic member 78. The washer 79 is positioned radially outward from the inner cylinder portion 83. The washer 79 is annular. The washer 79 is positioned to surround the inner cylinder portion 83. The washer 79 is positioned inside the recess 89. The washer 79 is supported by at least a portion of the hammer 75 inside the recess 89. In this embodiment, the washer 79 is positioned in an annular groove 92 provided in the support surface 90.

[0139] The rear end of the elastic member 78 contacts the front surface of the cam ring 76. The front end of the elastic member 78 contacts the washer 79. The front end of the elastic member 78 is connected to the hammer 75 via the washer 79. In this embodiment, the rear end of the elastic member 78 refers to the rear end of the disc spring 91 that is positioned furthest rear among the multiple disc springs 91 arranged in the axial direction. The front end of the elastic member 78 refers to the front end of the disc spring 91 that is positioned furthest forward among the multiple disc springs 91 arranged in the axial direction.

[0140] The rotating balls 80 are positioned between the spindle shaft portion 64 and the hammer 75. The rotating balls 80 are positioned between the ball grooves 70 and 85. Some of the rotating balls 80 are positioned in the ball grooves 70, and some of the rotating balls 80 are positioned in the ball grooves 85. Multiple rotating balls 80 are positioned around the rotation axis AX of the spindle 26. As described above, the hammer 75 can rotate relative to the spindle shaft portion 64. The rotating balls 80 function as bearings for the hammer 75. The rotating balls 80 enable smooth relative rotation between the hammer 75 and the spindle shaft portion 64.

[0141] (Elastic force adjustment mechanism) The elastic force adjustment mechanism 29 adjusts the elastic force of the elastic member 78 in the initial state before the motor 6 is started. The elastic force adjustment mechanism 29 adjusts the elastic force of the elastic member 78 by adjusting the amount of compression of the elastic member 78 in the initial state.

[0142] The rear end of the elastic member 78 is supported by the flange portion 65 via a cam ring 76. The elastic force adjustment mechanism 29 adjusts the amount of compression of the elastic member 78 by moving the position of the front end of the elastic member 78.

[0143] The elastic force adjustment mechanism 29 includes a screw 93 that contacts a washer 79. The screw 93 is connected to the front end of the elastic member 78 via the washer 79. The screw 93 is positioned in a screw hole 94 formed in the hammer 75. The screw hole 94 is formed to penetrate the front end surface 95 and the support surface 90 of the rear outer cylinder portion 81. In a plane perpendicular to the rotation axis AX, the front end surface 95 is annular. The front end surface 95 faces forward. Multiple screw holes 94 are formed at intervals around the rotation axis AX of the hammer 75. One screw 93 is positioned in each of the multiple screw holes 94. In this embodiment, six screw holes 94 are formed at intervals around the rotation axis AX. One screw 93 is positioned in each of the six screw holes 94.

[0144] The rear end of the screw 93 contacts the front surface of the washer 79. The amount of compression of the elastic member 78 is adjusted by the rotation of the screw 93. When the screw 93 rotates in one direction, the screw 93 moves backward relative to the hammer 75. As the screw 93 moves backward, the front end of the elastic member 78 moves backward via the washer 79. With the rear end of the elastic member 78 supported by the flange portion 65 via the cam ring 76, the elastic member 78 is compressed as the front end of the elastic member 78 moves backward. When the screw 93 rotates in the other direction, the screw 93 moves forward relative to the hammer 75. With the rear end of the elastic member 78 supported by the flange portion 65 via the cam ring 76, the elastic member 78 is stretched as the front end of the elastic member 78 moves forward.

[0145] The compression amount of the elastic member 78 is adjusted during the assembly of the impact tool 1. After the spindle 26, hammer 75, and cam ring 76 are connected so that the elastic member 78 is positioned in the enclosed space defined by the spindle shaft portion 64, hammer 75, and cam ring 76, a screw tightening tool is inserted into the screw hole 94 from in front of the front end face 95. The tip of the screw tightening tool is inserted into the tool hole of the screw 93 through the screw hole 94. The assembler can adjust the compression amount of the elastic member 78 by rotating the screw 93 via the screw tightening tool. In addition, the inclination angle of the elastic member 78 relative to the spindle 26 is adjusted by adjusting the axial position of each of the multiple screws 93.

[0146] (Hammer bearing) The hammer bearing 30 rotatably supports the hammer 75. The hammer bearing 30 is held in the hammer case 23. The hammer bearing 30 is positioned around the hammer 75. In this embodiment, the hammer bearing 30 rotatably supports the front end of the hammer 75. In this embodiment, the hammer bearing 30 is positioned around the front outer cylinder portion 82. At least a portion of the rear end of the hammer bearing 30 contacts the front end surface 95 of the rear outer cylinder portion 81. The hammer case 23 has an opposing surface 96 that faces the front end of the hammer bearing 30. The opposing surface 96 faces rearward. The front end of the hammer bearing 30 and the opposing surface 96 of the hammer case 23 face each other with a gap in between. The hammer bearing 30 is a ball bearing. The outer ring of the hammer bearing 30 contacts the inner circumferential surface of the large cylinder portion 53 of the hammer case 23. The inner ring of the hammer bearing 30 contacts the outer circumferential surface of the front outer cylinder portion 82 of the hammer 75.

[0147] In this embodiment, the hammer bearing 30 is positioned to cover the front end of the screw hole 94. During the assembly of the impact tool 1, the screw 93 is rotated by a screw tightening tool to adjust the compression amount of the elastic member 78, after which the hammer bearing 30 is positioned around the front outer cylinder portion 82.

[0148] (Tool holding shaft) Figure 21 is a front perspective view showing the tool holding shaft 31 according to this embodiment. Figure 22 is a cross-sectional view showing the tool holding shaft 31 according to this embodiment.

[0149] The tool holding shaft 31 is the output section of the impact tool 1, which rotates based on the rotational force of the rotor 36. At least a portion of the tool holding shaft 31 is positioned in front of the spindle 26. The tool holding shaft 31 has a tool holding section 97 and an anvil section 98 positioned behind the tool holding section 97. The tool holding section 97 is rod-shaped and extends in the front-rear direction. The anvil section 98 is connected to the rear of the tool holding section 97.

[0150] The tool holder portion 97 holds the tip tool. The tool holder portion 97 has a tool hole 99 into which the tip tool is inserted. The tool hole 99 is formed to extend rearward from the front end surface of the tool holder portion 97. The tip tool is mounted on the tool holder shaft 31.

[0151] The anvil portion 98 is positioned rearward of the tool holder portion 97. The anvil portion 98 is connected to the rear of the tool holder portion 97. The anvil portion 98 is positioned to surround the rotating shaft AX. The anvil portion 98 has a recess 100 into which the front end of the spindle shaft portion 64 is inserted. The front end of the spindle shaft portion 64, including the spindle projection 69, is positioned inside the recess 100. The recess 100 is formed to recess forward from the rear end surface of the anvil portion 98. The recess 100 is defined by the inner circumferential surface 101 of the anvil portion 98 and the opposing surface 102 connected to the front end of the inner circumferential surface 101 of the anvil portion 98. The opposing surface 102 is a flat surface facing rearward.

[0152] The anvil portion 98 has an anvil hole 104 that penetrates the outer circumferential surface 103 and the inner circumferential surface 101 of the anvil portion 98. The anvil hole 104 is formed to extend in the radial direction. Two anvil holes 104 are provided around the rotation axis AX. The two anvil holes 104 are arranged to sandwich the rotation axis AX.

[0153] In this embodiment, a support ball 106 is supported at the front end of the spindle shaft portion 64. A support recess 105 is provided on the front end surface of the spindle shaft portion 64. The inner surface of the support recess 105 is hemispherical. The support ball 106 is positioned in the support recess 105. The support ball 106 is in contact with the opposing surface 102.

[0154] The tool holding shaft 31 is rotatably supported by a shaft bearing 32. The shaft bearing 32 is positioned around the tool holding portion 97. The shaft bearing 32 is positioned inside the small cylindrical portion 54 of the hammer case 23. The shaft bearing 32 is held in the small cylindrical portion 54 of the hammer case 23. The shaft bearing 32 rotatably supports the front part of the tool holding portion 97. In this embodiment, two shaft bearings 32 are positioned axially. An O-ring 107 is positioned between the shaft bearing 32 and the rear holding portion.

[0155] A restraining member 108 is positioned behind the shaft bearing 32 to prevent it from coming out of the shaft bearing 32. The restraining member 108 is positioned in a groove 109 formed on the inner circumferential surface of the small cylindrical portion 54. A snap ring or a C-ring is exemplified as the restraining member 108. The restraining member 108 is positioned to contact the rear end surface of the shaft bearing 32. The restraining member 108 prevents the shaft bearing 32 from coming out of the small cylindrical portion 54.

[0156] (Movable Anvil) The movable anvil 33 is movably supported on the tool holding shaft 31. In this embodiment, the movable anvil 33 moves only radially relative to the tool holding shaft 31. The movable anvil 33 does not move axially or radially relative to the tool holding shaft 31.

[0157] The movable anvil 33 is movably supported on the anvil section 98. The movable anvil 33 is positioned in the anvil hole 104. One movable anvil 33 is positioned in each of the two anvil holes 104. The movable anvil 33 is a cylindrical (pin-shaped) member. The movable anvil 33 is positioned in the anvil hole 104 such that the central axis of the movable anvil 33 is parallel to the rotation axis AX of the tool holding shaft 31. In the following description, one of the movable anvils 33 will be appropriately referred to as the first movable anvil 331, and the other movable anvil 33 will be appropriately referred to as the second movable anvil 332.

[0158] The movable anvil 33 can move radially while being guided by the anvil hole 104. The inner surface of the anvil hole 104 functions as a guide surface that guides the movable anvil 33 radially. The front end of the spindle shaft portion 64 is positioned in the recess 100 of the anvil portion 98. A spindle projection 69 is positioned at the front end of the spindle shaft portion 64. When the spindle projection 69 contacts the movable anvil 33, the movable anvil 33 moves radially outward. When the spindle projection 69 moves away from the movable anvil 33, the movable anvil 33 moves radially inward.

[0159] The movable anvil 33 moves such that it changes between a first state in which at least a portion of the movable anvil 33 protrudes radially outward from the outer circumferential surface 103 of the anvil portion 98 of the tool holding shaft 31, and a second state in which the movable anvil 33 is positioned radially inward from the outer circumferential surface 103 of the anvil portion 98 of the tool holding shaft 31. During the rotation of the spindle 26, the movable anvil 33 changes from the second state to the first state when the spindle projection 69 comes into contact with the movable anvil 33. That is, when the spindle projection 69 comes into contact with the movable anvil 33, at least a portion of the movable anvil 33 is positioned radially outward from the outer circumferential surface 103 of the anvil portion 98.

[0160] When the movable anvil 33 is in the first state, the hammer projection 84 of the hammer 75 can contact the movable anvil 33. The hammer 75 strikes the movable anvil 33 when it is in the first state. When the movable anvil 33 is in the second state, the hammer projection 84 of the hammer 75 cannot contact the movable anvil 33. The hammer 75 rotates around the spindle shaft portion 64 when the movable anvil 33 is in the second state.

[0161] (Tool holding mechanism) The tool holding mechanism 34 is positioned in front of the hammer case 23 and around the tool holding section 97. The tool holding mechanism 34 holds the tip tool inserted into the tool hole 99 of the tool holding section 97. The tool holding mechanism 34 is detachable from the tip tool.

[0162] The tool holding mechanism 34 comprises a holding ball 110, a leaf spring 111, a sleeve 112, a coil spring 113, and a positioning member 114.

[0163] The tool holding portion 97 has a support recess 115 that supports the retaining ball 110. The support recess 115 is formed on the outer surface of the tool holding portion 97. In this embodiment, two support recesses 115 are formed in the tool holding portion 97.

[0164] The retaining ball 110 is movably supported in the tool holding portion 97. The retaining ball 110 is positioned in the support recess 115. One retaining ball 110 is positioned in each support recess 115.

[0165] A through hole is formed in the tool holding portion 97, connecting the inner surface of the support recess 115 and the inner surface of the tool hole 99. The diameter of the retaining ball 110 is smaller than the diameter of the innermost part of the through hole in the radial direction. With the retaining ball 110 supported in the support recess 115, it is positioned inside the tool hole 99 through at least a portion of the retaining ball 110. The retaining ball 110 can fix the tip tool inserted into the tool hole 99. The retaining ball 110 is movable between an engaged position that fixes the tip tool and a released position that releases the fixation of the tip tool.

[0166] The leaf spring 111 generates an elastic force that moves the retaining ball 110 to the engagement position. The leaf spring 111 is positioned around the tool holding portion 97. The leaf spring 111 generates an elastic force that moves the retaining ball 110 forward.

[0167] The sleeve 112 is a cylindrical member. The sleeve 112 is positioned around the tool holder 97. The sleeve 112 is axially movable around the tool holder 97. The sleeve 112 can prevent the retaining ball 110, which is positioned in the engaged position, from disengaging from the engaged position. By moving the sleeve 112 axially, the retaining ball 110 can be moved from the engaged position to the disengaged position.

[0168] The sleeve 112 is movable around the tool holding portion 97 between a blocking position that prevents the holding ball 110 from moving radially outward and a permitting position that allows radial outward movement.

[0169] By positioning the sleeve 112 in the blocking position, the retaining ball 110, which is positioned in the engagement position, is prevented from moving radially outward. In other words, by positioning the sleeve 112 in the blocking position, the retaining ball 110, which is positioned in the engagement position, is prevented from disengaging from the engagement position. By positioning the sleeve 112 in the blocking position, the tip tool is maintained in a state where it is fixed by the retaining ball 110.

[0170] When the sleeve 112 is moved to the allowable position, the retaining ball 110, which is positioned in the engaged position, is allowed to move radially outward. When the sleeve 112 is moved to the allowable position, it changes the state in which the retaining ball 110 can move from the engaged position to the released position. That is, when the sleeve 112 is positioned in the allowable position, the retaining ball 110, which is positioned in the engaged position, is allowed to disengage from the engaged position. When the sleeve 112 is positioned in the allowable position, the state in which the tip tool is fixed by the retaining ball 110 becomes release.

[0171] The coil spring 113 generates an elastic force that causes the sleeve 112 to move to the stop position. The coil spring 113 is positioned around the tool holder 97. The stop position is defined as being behind the allowable position. The coil spring 113 generates an elastic force that moves the sleeve 112 backward.

[0172] The positioning member 114 is a ring-shaped member fixed to the outer surface of the tool holding portion 97. The positioning member 114 is fixed in a position that can face the rear end of the sleeve 112. The positioning member 114 positions the sleeve 112 in a blocking position. The sleeve 112, which is subjected to an elastic force that moves it backward from the coil spring 113, is positioned in the blocking position by contacting the positioning member 114.

[0173] <Impact tool operation> Next, the operation of the impact tool 1 will be described. Figures 23 to 32 are cross-sectional views showing the operation of the output assembly 4 according to this embodiment. Figures 23, 25, 27, 29, and 31 each correspond to the cross-sectional view of the output assembly 4 shown in Figure 5, along the line CC. Figures 24, 26, 28, 30, and 32 each correspond to the cross-sectional view of the output assembly 4 shown in Figure 5, along the line GG.

[0174] In this embodiment, the spindle projection 69 includes a first spindle projection 691 and a second spindle projection 692. The hammer projection 84 includes a first hammer projection 841 and a second hammer projection 842. The movable anvil 33 includes a first movable anvil 331 and a second movable anvil 332.

[0175] When performing screw tightening work on a workpiece, the tip tool (driver bit) used for screw tightening is inserted into the tool hole 99 of the tool holding shaft 31. The tip tool inserted into the tool hole 99 is held by the tool holding mechanism 34. After the tip tool is mounted on the tool holding shaft 31, the operator grips the grip portion 18 with their right hand, for example, and pulls the trigger lever 9 with their right index finger. When the trigger lever 9 is pulled, power is supplied from the battery pack 20 to the motor 6, starting the motor 6 and turning on the light. The motor 6 starts, causing the rotor shaft 42 of the rotor 36 to rotate. As the rotor shaft 42 rotates, the rotational force of the rotor shaft 42 is transmitted to the planetary gear 58 via the pinion gear 48. The planetary gear 58 rotates on its own axis and revolves around the pinion gear 48 while meshing with the internal teeth of the internal gear 60. The planetary gear 58 is rotatably supported on the spindle 26 via a pin. Due to the revolution of the planetary gear 58, the spindle 26 rotates at a lower rotational speed than the rotational speed of the rotor shaft 42.

[0176] During screw tightening, the tool holding shaft 31 rotates in the forward direction. Furthermore, during screw tightening, the tool holding shaft 31 is subjected to a load in the reverse direction.

[0177] Figures 23 and 24 show cross-sectional views of the output assembly 4 in a low-load state, where the tool holding shaft 31 is rotating with a low load.

[0178] As shown in Figure 23, under low load conditions, the spindle projection 69 and the movable anvil 33 are in contact, and the movable anvil 33 is in contact with the hammer projection 84.

[0179] Under low load conditions, the movable anvil 33 moves radially outward due to contact with the spindle projection 69. At least a portion of the movable anvil 33 is positioned radially outward from the outer circumferential surface of the anvil portion 98. Since at least a portion of the movable anvil 33 is positioned radially outward from the outer circumferential surface of the anvil portion 98, under low load conditions, the hammer projection 84 contacts at least a portion of the movable anvil 33.

[0180] Under low load conditions, the wedge effect of the movable anvil 33 prevents it from passing between the spindle projection 69 and the hammer projection 84, thereby preventing relative rotation between the spindle 26, the hammer 75, and the tool holding shaft 31. The tool holding shaft 31 rotates together with the hammer 75 and the spindle 26 via the movable anvil 33.

[0181] The cam ring 76 is connected to the hammer 75 via a guide groove 86 and a cam slide portion 87. The cam ring 76 is also pressed against the flange portion 65 of the spindle 26 by the elastic force of the elastic member 78. Therefore, in low-load conditions where the hammer 75 and the spindle 26 do not rotate relative to each other, the cam ring 76 rotates together with the spindle 26 and the hammer 75. In other words, in low-load conditions, the spindle 26, the hammer 75, the tool holding shaft 31, and the cam ring 76 rotate together.

[0182] As shown in Figure 24, under low load conditions, the cam ring 76 and spindle 26 rotate together with the ball 77 positioned in the center of the spindle groove 71 (the boundary between the first portion 711 and the second portion 712). Under low load conditions, in the axial direction, the cam ring 76 is positioned at the rear end of the rear outer cylinder portion 81 of the hammer 75.

[0183] Figures 25 and 26 show cross-sectional views of the output assembly 4 in the transition state immediately after the load on the tool holding shaft 31 transitions from a low load state to a high load state.

[0184] As the screw tightening operation progresses, the load on the tool holding shaft 31 increases, causing the rotational speed of the tool holding shaft 31 to decrease. Since the hammer 75 is connected to the tool holding shaft 31 via the movable anvil 33, the rotational speed of the hammer 75 decreases as the rotational speed of the tool holding shaft 31 decreases. Also, since the cam ring 76 is connected to the hammer 75 via the guide groove 86 and the cam slide portion 87, the rotational speed of the cam ring 76 decreases as the rotational speed of the hammer 75 decreases. On the other hand, the spindle 26 rotates due to the rotational force of the motor 6, so the rotational speed of the spindle 26 does not decrease.

[0185] Although the rotational speed of the spindle 26 does not decrease, the rotational speeds of the tool holding shaft 31, hammer 75, and cam ring 76 decrease, so relative rotation between the tool holding shaft 31, hammer 75, and cam ring 76 and the spindle 26 begins. The tool holding shaft 31, hammer 75, and cam ring 76 rotate together.

[0186] As shown in Figure 25, when transitioning from a low-load state to a high-load state, the relative rotation between the tool holding shaft 31 and the hammer 75 and the spindle 26 causes the spindle projection 69 to separate from the movable anvil 33.

[0187] Since the cam ring 76 is connected to the hammer 75 via the guide groove 86 and the cam slide portion 87, the rotational speed of the cam ring 76 decreases as the rotational speed of the hammer 75 decreases. The rotational speed of the spindle 26 does not decrease, so if the rotation of the spindle 26 continues while the rotational speed of the cam ring 76 has decreased, the ball 77 moves inside the spindle groove 71 and the cam groove 88.

[0188] As shown in Figure 26, when transitioning from a low-load state to a high-load state, the ball 77 moves along the second portion 712 from the center to the end of the spindle groove 71. The cam ring 76 receives force from the ball 77 and moves forward. The cam ring 76 moves forward guided by the guide groove 86. The cam ring 76 moves forward against the elastic force of the elastic member 78.

[0189] Thus, when the flange portion 65 of the spindle 26 and the cam ring 76 are rotating together in the forward direction, and the tool holding shaft 31 transitions from a low load state to a high load state, causing the rotational speed of the cam ring 76 to decrease and the flange portion 65 and the cam ring 76 to begin relative rotation, the ball 77 moves the second portion 712 from the center of the spindle groove 71 toward the other end of the second portion 712 in the circumferential direction, causing the cam ring 76 to receive force from the ball 77 and move forward.

[0190] Figures 27 and 28 show cross-sectional views of the output assembly 4 in the high-load state after a predetermined time has elapsed since the transition from the low-load state to the high-load state.

[0191] Due to the continued high load, the rotation of the tool holding shaft 31, hammer 75, and cam ring 76 stops. Even though the rotation of the tool holding shaft 31, hammer 75, and cam ring 76 stops, the spindle 26 continues to rotate due to the rotational force of the motor 6.

[0192] When the tool holding shaft 31 is under high load, the rotation of the tool holding shaft 31, the hammer 75, and the cam ring 76 stops, while the rotation of the spindle 26 continues. The cam ring 76 receives force from the ball 77 and moves forward against the elastic force of the elastic member 78.

[0193] As shown in Figure 27, with the rotation of the tool holding shaft 31, hammer 75, and cam ring 76 all stopped, the rotation of the spindle 26 continues, causing the spindle projection 69 to move further away from the movable anvil 33 in the direction of rotation. As the spindle projection 69 moves away from the movable anvil 33, the movable anvil 33 becomes movable radially inward. As the movable anvil 33 moves radially inward beyond the outer circumferential surface 103 of the anvil portion 98, the hammer projection 84 and the movable anvil 33 separate. That is, the lock of the hammer 75 by the movable anvil 33 is released, and the hammer 75 becomes rotatable relative to the spindle 26.

[0194] When the lock on the hammer 75 is released, the cam ring 76 also becomes rotatable relative to the spindle 26. The cam ring 76 moves backward relative to the hammer 75 due to the elastic force of the elastic member 78. The cam ring 76 moves backward guided by the guide groove 86. Since the cam ring 76 is rotatable relative to the spindle 26, as it moves backward, it receives force from the ball 77 and rotates in the forward direction. That is, the cam ring 76 rotates in the forward direction while moving backward. The ball 77 moves along the second portion 712 from the end of the spindle groove 71 toward the center. Since the hammer 75 is connected to the cam ring 76 via the cam slide portion 87 and the guide groove 86, as the cam ring 76 rotates in the forward direction, the hammer 75 also rotates in the forward direction.

[0195] Thus, after the hammer 75 is released, if the cam ring 76 receives an elastic force from the elastic member 78 to move backward, the ball 77 moves the second portion 712 from the other circumferential end of the second portion 712 toward the center of the spindle groove 71, and the cam ring 76 receives a force from the ball 77 and moves backward while rotating relative to the flange portion 65.

[0196] Figures 29 and 30 show cross-sectional views of the output assembly 4 in the hammer rotation state, where the hammer 75 is rotating to strike the movable anvil 33.

[0197] As shown in Figure 29, when the hammer 75 is rotating, the spindle 26 rotates in the forward direction due to the rotational force of the motor 6. The hammer 75 rotates in the forward direction together with the cam ring 76, which rotates due to the elastic force of the elastic member 78. The spindle 26 rotates such that the first spindle projection 691, which is away from the first movable anvil 331, approaches the second movable anvil 332, and the second spindle projection 692, which is away from the second movable anvil 332, approaches the first movable anvil 331. The hammer 75 also rotates such that the first hammer projection 841, which is away from the first movable anvil 331, approaches the second movable anvil 332, and the second hammer projection 842, which is away from the second movable anvil 332, approaches the first movable anvil 331.

[0198] The first hammer projection 841 rotates in the forward direction around the spindle 26, following the first spindle projection 691. The first spindle projection 691 reaches the second movable anvil 332 before the first hammer projection 841. The second hammer projection 842 rotates in the forward direction around the spindle 26, following the second spindle projection 692. The second spindle projection 692 reaches the first movable anvil 331 before the second hammer projection 842.

[0199] Figures 31 and 32 show cross-sectional views of the output assembly 4 in the striking state, where the hammer 75 is striking the movable anvil 33.

[0200] As described above, the first spindle projection 691 reaches the second movable anvil 332 before the first hammer projection 841. The first spindle projection 691 contacts the second movable anvil 332. The second movable anvil 332 moves radially outward due to contact with the first spindle projection 691. At least a portion of the second movable anvil 332 is positioned radially outward from the outer circumferential surface 103 of the anvil portion 98.

[0201] The first hammer projection 841 reaches the second movable anvil 332 after the first spindle projection 691 has reached the second movable anvil 332. That is, the first hammer projection 841 reaches the second movable anvil 332 after the second movable anvil 332 has moved radially outward. The first hammer projection 841 strikes the second movable anvil 332, which is positioned radially outward from the outer circumferential surface 103 of the anvil portion 98, in the rotational direction. When the second movable anvil 332 is struck by the first hammer projection 841, the position of the second movable anvil 332 in the radial direction is constrained by the first spindle projection 691, and the position of the second movable anvil 332 in the circumferential direction is constrained by the inner surface of the anvil hole 104. This allows the first hammer projection 841 to strike the second movable anvil 332.

[0202] The second spindle projection 692 reaches the first movable anvil 331 before the second hammer projection 842. The first movable anvil 331 moves radially outward due to contact with the second spindle projection 692. The second hammer projection 842 reaches the first movable anvil 331 after it has moved radially outward. The second hammer projection 842 strikes the first movable anvil 331, which is positioned radially outward from the outer circumferential surface 103 of the anvil portion 98, in the rotational direction. When the first movable anvil 331 is struck by the second hammer projection 842, the position of the first movable anvil 331 in the radial direction is constrained by the second spindle projection 692, and the position of the first movable anvil 331 in the circumferential direction is constrained by the inner surface of the anvil hole 104. This allows the second hammer projection 842 to strike the first movable anvil 331.

[0203] The striking of the second movable anvil 332 by the first hammer projection 841 and the striking of the first movable anvil 331 by the second hammer projection 842 occur substantially simultaneously. The movable anvil 33 is struck by the hammer projection 84 while positioned in the anvil hole 104 of the tool holding shaft 31. The tool holding shaft 31 is struck in the rotational direction by the hammer 75 via the two movable anvils 33.

[0204] The tool holding shaft 31 is struck in the rotational direction by the hammer 75, causing it to rotate around the rotation axis AX with high torque. As a result, the screw is tightened to the workpiece with high torque.

[0205] As shown in Figure 32, as the cam ring 76 moves backward, in the striking state, the ball 77 is positioned in the center of the spindle groove 71 (the boundary between the first portion 711 and the second portion 712).

[0206] After the striking state ends, output assembly 4 transitions from the striking state to the low-load state.

[0207] As explained with reference to Figures 23 to 32, in this embodiment, the movable anvil 33 is struck by the hammer projection 84 when the spindle 26 rotates half a turn. That is, in this embodiment, the movable anvil 33 is struck twice by the hammer projection 84 during one rotation of the spindle 26. Alternatively, the movable anvil 33 may be struck once by the hammer projection 84 during one rotation of the spindle 26. When the movable anvil 33 is struck once by the hammer projection 84 during one rotation of the spindle 26, the hammer projection 84 can strike the movable anvil 33 with a higher rotational speed and higher inertial force compared to when the movable anvil 33 is struck twice. That is, when the movable anvil 33 is struck once by the hammer projection 84 during one rotation of the spindle 26, the hammer 75 can strike the movable anvil 33 with higher striking energy compared to when the movable anvil 33 is struck twice. By adjusting either or both the elastic energy (spring constant) of the elastic member 78 and the rotational speed of the spindle 26, the number of times the hammer projection 84 strikes the movable anvil 33 during one rotation of the spindle 26 can be adjusted. As a secondary effect, due to the ease with which the elastic member 78 deforms, the timing of the start of the hammer projection 84 striking the movable anvil 33 is advanced, thereby suppressing the occurrence of cam-out, a phenomenon in which the tip of the cutting tool comes out of the tool hole (cross hole) of the screw during screw tightening.

[0208] In this embodiment, two movable anvils 33 and two hammer projections 84 are provided. Alternatively, three movable anvils 33 and three hammer projections 84 may be provided. Alternatively, four movable anvils 33 and four hammer projections 84 may be provided. Furthermore, five or more movable anvils 33 and hammer projections 84 may each be provided.

[0209] The examples shown in Figures 23 to 32 are examples in which the spindle 26, cam ring 76, hammer 75, and tool holding shaft 31 rotate in the forward direction for screw tightening work. When loosening a screw, the operator operates the forward / reverse switching lever 10 to rotate the spindle 26, cam ring 76, hammer 75, and tool holding shaft 31 in the reverse direction. In screw loosening work, when the flange portion 65 of the spindle 26 and the cam ring 76 are rotating together in the reverse direction, the tool holding shaft 31 is under high load, the rotational speed of the cam ring 76 decreases, and the flange portion 65 and the cam ring 76 begin to rotate relative to each other. As a result, the ball 77 moves the first portion 711 from the center of the spindle groove 71 toward one end of the first portion 711 in the circumferential direction, and the cam ring 76 receives force from the ball 77 and moves forward. Furthermore, after the hammer 75 is released, if the cam ring 76 receives an elastic force from the elastic member 78 to move backward, the ball 77 moves the first portion 711 from one circumferential end toward the center of the spindle groove 71, causing the cam ring 76 to receive force from the ball 77 and move backward while the flange portion 65 rotates relative to it.

[0210] <Effects> As described above, in this embodiment, the impact tool 1 may include a motor 6, a spindle 26 having a spindle shaft portion 64 and a flange portion 65 provided at the rear of the spindle shaft portion 64 and rotating by the rotational force of the motor 6, a tool holding shaft 31 in which at least a part is positioned in front of the spindle 26, a hammer 75 supported by the spindle shaft portion 64 and striking the tool holding shaft 31 in the rotational direction, an elastic member 78 positioned in the axial direction between the front surface of the flange portion 65 and the support surface 90 of the hammer 75 positioned in front of the flange portion 65, and an elastic force adjustment mechanism 29 that adjusts the elastic force of the elastic member 78 in the initial state before the motor 6 is started.

[0211] In the above configuration, since the elastic force of the elastic member 78 is adjustable, the impact tool 1 can smoothly perform both high-load and low-load operations. When low-load operations are performed, the elastic force of the elastic member 78 is adjusted to be low, and when high-load operations are performed, the elastic force of the elastic member 78 is adjusted to be high, thereby enabling the impact tool 1 to smoothly perform both high-load and low-load operations.

[0212] In this embodiment, the elastic force adjustment mechanism 29 may adjust the amount of compression of the elastic member 78 in the initial state.

[0213] In the above configuration, the elastic force of the elastic member 78 is adjusted by adjusting the amount of compression of the elastic member 78 in the initial state. When the amount of compression is small, the elastic force of the elastic member 78 becomes low, and when the amount of compression is large, the elastic force of the elastic member 78 becomes high.

[0214] In this embodiment, the rear end of the elastic member 78 may be supported by the flange portion 65. The elastic force adjustment mechanism 29 may adjust the amount of compression by moving the position of the front end of the elastic member 78.

[0215] In the above configuration, the compression amount is adjusted by moving the position of the front end of the elastic member 78 while the position of the rear end of the elastic member 78 is fixed.

[0216] In this embodiment, the elastic force adjustment mechanism 29 may have a screw 93 positioned in a screw hole 94 formed in the hammer 75 and connected to the front end of the elastic member 78. The amount of compression may be adjusted by rotating the screw 93.

[0217] In the above configuration, the screw 93 moves in the front-to-back direction when it is rotated while positioned in the screw hole 94, thereby adjusting the amount of compression.

[0218] In this embodiment, the impact tool 1 may include a washer 79 that supports the front end of the elastic member 78. The rear end of the screw 93 may be in contact with the front surface of the washer 79. The screw 93 may be connected to the elastic member 78 via the washer 79.

[0219] In the above configuration, the front end of the elastic member 78 moves smoothly.

[0220] In this embodiment, multiple screw holes 94 may be formed at intervals around the rotation axis of the hammer 75. One screw 93 may be placed in each of the multiple screw holes 94.

[0221] In the above configuration, the compression amount of the elastic member 78 is adjusted by adjusting the position of each of the multiple screws 93 in the front-rear direction, and the inclination angle of the elastic member 78 with respect to the spindle 26 is also adjusted.

[0222] In this embodiment, the hammer 75 may have an inner cylinder portion 83 arranged around the spindle shaft portion 64, a front outer cylinder portion 82 arranged radially outward and forward of the inner cylinder portion 83, and a rear outer cylinder portion 81 arranged radially outward of the front outer cylinder portion 82 and rearward of the front outer cylinder portion 82. The screw hole 94 may be formed to penetrate the front end surface 95 and the support surface 90 of the rear outer cylinder portion 81.

[0223] In the above configuration, the assembler or operator of the impact tool 1 can smoothly bring the screw tightening tool into contact with the screw 93 positioned in the screw hole 94, and rotate the screw 93 smoothly.

[0224] In this embodiment, the impact tool 1 may include a hammer case 23 that houses a hammer 75, and a hammer bearing 30 that is held in the hammer case 23 and rotatably supports the hammer 75. The hammer bearing 30 may be arranged around the front outer cylinder portion 82.

[0225] In the above configuration, after the adjustment of the elastic force by the screw 93 is completed, the hammer bearing 30 is positioned to cover the front end of the screw hole 94. This protects the screw 93 from the hammer bearing 30.

[0226] In this embodiment, the elastic member 78 may include a disc spring 91.

[0227] In the above configuration, the size of the impact tool 1 is suppressed. When a predetermined elastic force is required for the elastic member 78, using a disc spring 91 allows for a shorter axial dimension of the elastic member 78 compared to, for example, using a coil spring. As a result, the hammer 75 can strike the tool holding shaft 31 in the rotational direction while suppressing the size of the impact tool 1. In particular, the axial length of the impact tool 1 is shortened. When the impact tool 1 has a motor housing 17, a rear cover 3 positioned at the rear end of the motor housing 17, and an output assembly 4 positioned at the front of the motor housing 17, the axial length of the impact tool 1 refers to the axial distance between the rear end of the rear cover 3 and the front end of the output assembly 4.

[0228] In this embodiment, the impact tool 1 may include a washer 79 that supports the front end of the elastic member 78. The front end of the elastic member 78 may be connected to the hammer 75 via the washer 79.

[0229] In the above configuration, the front end of the elastic member 78 is stably connected to the hammer 75 via a washer 79.

[0230] In this embodiment, the impact tool 1 may include a movable anvil 33 movably supported on the tool holding shaft 31. The hammer 75 may strike the movable anvil 33 in the rotational direction without axial displacement.

[0231] In the above configuration, a movable anvil 33 is provided which is movably supported on the tool holding shaft 31, so that the hammer 75 can strike the movable anvil 33 in the rotational direction without axial displacement. Since the hammer 75 does not axially displace, the generation of axial vibration in the impact tool 1 is suppressed.

[0232] In this embodiment, the movable anvil 33 may move to change between a first state in which at least a portion of the movable anvil 33 protrudes radially outward from the outer circumferential surface of the tool holding shaft 31, and a second state in which the movable anvil 33 is positioned radially inward from the outer circumferential surface of the tool holding shaft 31. The hammer 75 may strike the movable anvil 33 in the first state and rotate around the spindle shaft portion 64 in the second state.

[0233] In the above configuration, the hammer 75 can strike the movable anvil 33 in the rotational direction without being displaced in the axial direction.

[0234] In this embodiment, the impact tool 1 may include a cam ring 76 that is rotatably connected to the flange portion 65 via a ball 77 and axially movable and non-rotatably connected to the hammer 75. The cam ring 76 may be positioned opposite the front surface of the flange portion 65. The elastic member 78 may be positioned axially between the front surface of the cam ring 76 and the support surface of the hammer 75.

[0235] In the above configuration, the cam ring 76 is connected to the flange portion 65 of the spindle 26 via a ball 77 so as to be rotatable relative to it. The cam ring 76 is also connected to the hammer 75 so as to be axially movable but not rotatable relative to it. This allows the hammer 75 to strike the tool holding shaft 31 in the rotational direction while the shaft length is shortened.

[0236] In this embodiment, the cam ring 76 may be connected to the rear of the hammer 75. The elastic member 78 may be positioned in the enclosed space defined by the spindle shaft portion 64, the hammer 75, and the cam ring 76.

[0237] In the above configuration, when the hammer 75 strikes the tool holding shaft 31 in the rotational direction via the movable anvil 33, the cam ring 76 and the elastic member 78 also rotate together with the hammer 75. That is, when the hammer 75 strikes the tool holding shaft 31, not only the moment of inertia of the hammer 75, but also the moment of inertia of the cam ring 76 and the moment of inertia of the elastic member 78 are applied to the tool holding shaft 31. As a result, the tool holding shaft 31 is struck with a high impact force.

[0238] [Second Embodiment] A second embodiment will now be described. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and the descriptions of those components will be simplified or omitted.

[0239] <Output Assembly> Figure 33 is a front perspective view showing a part of the impact tool 1B according to this embodiment. Figure 34 is a front perspective view showing the output assembly 4B according to this embodiment. Figure 35 is a longitudinal cross-sectional view showing the output assembly 4B according to this embodiment. Figure 36 is an exploded perspective view showing the output assembly 4B according to this embodiment.

[0240] The output assembly 4B includes a hammer case 123 and a bearing box 24. The hammer 175 is positioned in the internal space of the output assembly 4B defined by the hammer case 123 and the bearing box 24.

[0241] The hammer case 123 has a large cylindrical section 153 and a small cylindrical section 154. The large cylindrical section 153 and the small cylindrical section 154 are arranged to surround the rotation axis AX. The small cylindrical section 154 is positioned in front of the large cylindrical section 153. The inner diameter of the large cylindrical section 153 is larger than the inner diameter of the small cylindrical section 154. The outer diameter of the large cylindrical section 153 is larger than the outer diameter of the small cylindrical section 154.

[0242] In this embodiment, the hammer case 123 has through holes 116. The hammer case 123 has a front surface 155 facing forward and a rear surface 196 facing backward. The front surface 155 is provided so as to connect the front end of the outer circumferential surface of the large cylindrical portion 153 and the rear end of the outer circumferential surface of the small cylindrical portion 154. The rear surface 196 is provided so as to connect the front end of the inner circumferential surface of the large cylindrical portion 153 and the rear end of the inner circumferential surface of the small cylindrical portion 154. Both the front surface 155 and the rear surface 196 are annular. The through holes 116 are formed to penetrate the front surface 155 and the rear surface 196. Multiple through holes 116 are provided at intervals in the circumferential direction. In this embodiment, six through holes 116 are provided at intervals in the circumferential direction.

[0243] Similar to the embodiments described above, the output assembly 4B has a screw 93 as an elastic force adjustment mechanism 29. The hammer 175 has a screw hole 94 in which the screw 93 is located. In the radial direction, the distance between the rotation axis AX and the screw hole 94 is substantially equal to the distance between the rotation axis AX and the through hole 116. In the circumferential direction, the spacing between the multiple screw holes 94 is equal to the spacing between the multiple through holes 116. By adjusting the position of the hammer 175 in the rotation direction, the positions of the screw holes 94 and the through holes 116 coincide in both the radial and circumferential directions. That is, the through holes 116 can overlap with the screw holes 94 in both the radial and circumferential directions. By adjusting the position of the hammer 175 in the rotation direction, the screw 93 can face the through hole 116. An operator can insert a screw tightening tool into the through hole 116 and rotate the screw 93. As the screw 93 rotates, the washer 79 moves in the front-back direction. As the washer 79 moves in the front-rear direction, the amount of compression of the elastic member 78 is adjusted, and the elastic force of the elastic member 78 is adjusted.

[0244] The hammer 175 has a rear outer cylinder portion 181, a front outer cylinder portion 182, and an inner cylinder portion 183. The rear outer cylinder portion 181, the front outer cylinder portion 182, and the inner cylinder portion 183 are each arranged to surround the rotation axis AX. The rear outer cylinder portion 181, the front outer cylinder portion 182, and the inner cylinder portion 183 are integrally formed.

[0245] The front outer cylinder portion 182 is positioned in front of the rear outer cylinder portion 181. The front end of the rear outer cylinder portion 181 is connected to the rear end of the front outer cylinder portion 182. The outer diameter of the rear outer cylinder portion 181 is larger than the outer diameter of the front outer cylinder portion 182. The inner diameter of the rear outer cylinder portion 181 is larger than the inner diameter of the front outer cylinder portion 182.

[0246] The inner cylinder portion 183 is positioned radially inward from the rear outer cylinder portion 181 and the front outer cylinder portion 182. The front end of the inner cylinder portion 183 is connected to the rear end of the front outer cylinder portion 182.

[0247] The inner cylinder portion 183 is supported by the spindle 26. The front outer cylinder portion 182 is positioned radially outward and forward of the inner cylinder portion 183. The rear outer cylinder portion 181 is positioned radially outward of the inner cylinder portion 183 and the front outer cylinder portion 82, and rearward of the front outer cylinder portion 182.

[0248] In this embodiment, the rear outer cylinder portion 181 has a front small-diameter portion 181A, a large-diameter portion 181B, and a rear small-diameter portion 181C. The large-diameter portion 181B is positioned rearward from the front small-diameter portion 181A. The rear small-diameter portion 181C is positioned rearward from the large-diameter portion 181B. The outer diameter of the large-diameter portion 181B is larger than the outer diameter of the front small-diameter portion 181A and the outer diameter of the rear small-diameter portion 181C.

[0249] In this embodiment, the hammer 175 is rotatably supported by a first hammer bearing 130A and a second hammer bearing 130B. Each of the first hammer bearing 130A and the second hammer bearing 130B is positioned around the rear outer cylinder portion 181. The second hammer bearing 130B is positioned rearward of the first hammer bearing 130A. Each of the first hammer bearing 130A and the second hammer bearing 130B is a ball bearing.

[0250] The first hammer bearing 130A supports the front of the hammer 175. The second hammer bearing 130B supports the rear of the hammer 175. In this embodiment, each of the first hammer bearing 130A and the second hammer bearing 130B supports the rear outer cylinder portion 181. The first hammer bearing 130A supports the front of the rear outer cylinder portion 181. The second hammer bearing 130B supports the rear of the rear outer cylinder portion 181.

[0251] The first hammer bearing 130A is positioned around the front small-diameter portion 181A. The inner ring of the first hammer bearing 130A contacts the outer circumferential surface of the front small-diameter portion 181A. The outer ring of the first hammer bearing 130A contacts the inner circumferential surface of the large cylindrical portion 153. The hammer 175 has a support surface 197 facing the front end of the first hammer bearing 130A. The support surface 197 faces rearward. The front end of the first hammer bearing 130A contacts the support surface 197 of the hammer 175. The support surface 197 is positioned radially outward from the rear surface 196. The support surface 197 is positioned rearward from the rear surface 196. The rear end of the first hammer bearing 130A contacts at least a portion of the front end surface of the large-diameter portion 181B.

[0252] The second hammer bearing 130B is positioned around the rear small-diameter portion 181C. The inner ring of the second hammer bearing 130B contacts the outer circumferential surface of the rear small-diameter portion 181C. The outer ring of the second hammer bearing 130B contacts the inner circumferential surface of the large cylindrical portion 153. The front end of the second hammer bearing 130B contacts at least a portion of the rear end surface of the large-diameter portion 181B. In this embodiment, a plurality of notches 181D are provided in the rear small-diameter portion 181C. The notches 181D are formed to recess forward from the rear end of the rear small-diameter portion 181C. The plurality of notches 181D allow the rear small-diameter portion 181C to be elastically deformed in the radial direction. The elastic deformation of the rear small-diameter portion 181C fixes the second hammer bearing 130B and the rear small-diameter portion 181C. In other words, the rear small-diameter portion 181C generates an elastic force that pushes the second hammer bearing 130B radially outward. The second hammer bearing 130B is positioned around the rear small-diameter portion 181C so as to tighten it from the radially outward side. This fixes the second hammer bearing 130B and the rear small-diameter portion 181C together.

[0253] <Effects> As described above, in this embodiment, the hammer 175 may be supported by a first hammer bearing 130A and a second hammer bearing 130B. The second hammer bearing 130B may be positioned rearward of the first hammer bearing 130A.

[0254] In the above configuration, the rotation of the hammer 175 in a tilted state with respect to the spindle 26 is suppressed.

[0255] In the present embodiment, the hammer 175 may include an inner cylinder portion 183 supported by the spindle 26, a front outer cylinder portion 182 disposed radially outside and forward of the inner cylinder portion 183, and a rear outer cylinder portion 181 disposed radially outside of the inner cylinder portion 183 and rearward of the front outer cylinder portion 182. The outer diameter of the rear outer cylinder portion 181 may be larger than the outer diameter of the front outer cylinder portion 182. Each of the first hammer bearing 130A and the second hammer bearing 130B may support the rear outer cylinder portion 181.

[0256] In the above configuration, the rotation of the hammer 175 in a tilted state with respect to the spindle 26 is suppressed.

[0257] In the present embodiment, the first hammer bearing 130A may support the front portion of the rear outer cylinder portion 181. The second hammer bearing 130B may support the rear portion of the rear outer cylinder portion 181.

[0258] In the above configuration, the rotation of the hammer 175 in a tilted state with respect to the spindle 26 is suppressed.

[0259] In the present embodiment, the rear outer cylinder portion 181 may include a front small-diameter portion 181A, a large-diameter portion 181B disposed rearward of the front small-diameter portion 181A, and a rear small-diameter portion 181C disposed rearward of the large-diameter portion 181B. The outer diameter of the large-diameter portion 181B may be larger than the outer diameters of the front small-diameter portion 181A and the rear small-diameter portion 181C. The first hammer bearing 130A may be disposed around the front small-diameter portion 181A. The second hammer bearing 130B may be disposed around the rear small-diameter portion 181C.

[0260] In the above configuration, the enlargement of the hammer case 23 in the radial direction is suppressed.

[0261] In this embodiment, the hammer 175 may have a support surface 197 facing the front end of the first hammer bearing 130A. The front end of the first hammer bearing 130A may be in contact with the support surface 197 of the hammer 175.

[0262] In the above configuration, the first hammer bearing 130A is positioned in the axial direction.

[0263] In this embodiment, the rear end of the first hammer bearing 130A may be in contact with at least a portion of the front end surface of the large-diameter portion 181B.

[0264] In the above configuration, the first hammer bearing 130A is positioned in the axial direction.

[0265] In this embodiment, the front end of the second hammer bearing 130B may contact at least a portion of the rear end surface of the large-diameter portion 181B.

[0266] In the above configuration, the second hammer bearing 130B is positioned in the axial direction.

[0267] In this embodiment, a plurality of notches 181D may be provided in the rear small-diameter portion 181C. The plurality of notches 181D may cause the rear small-diameter portion 181C to elastically deform in the radial direction. The elastic deformation of the rear small-diameter portion 181C may fix the second hammer bearing 130B and the rear small-diameter portion 181C.

[0268] In the above configuration, the inner ring of the second hammer bearing 130B is positioned on the hammer 175.

[0269] In this embodiment, the output assembly 4B may include a hammer case 123 that houses the hammer 175. The hammer case 123 may have through holes 116 that overlap with the screw holes 94 in the radial and circumferential directions, respectively. The screw 93 may rotate through the through holes 116.

[0270] In the above configuration, the worker can smoothly bring the screw tightening tool into contact with the screw 93 positioned in the screw hole 94 through the through hole 116, and rotate the screw 93 smoothly. The worker can appropriately adjust the elastic force of the elastic member 78 according to the work being done.

[0271] In this embodiment, the output assembly 4B may include a first hammer bearing 130A and a second hammer bearing 130B that are held in the hammer case 23 and rotatably support the hammer 175. The first hammer bearing 130A and the second hammer bearing 130B may be arranged around the rear outer cylinder portion 181.

[0272] In the above configuration, the front end of the screw hole 94 is not covered by the first hammer bearing 130A and the second hammer bearing 130B, so that the worker can smoothly bring the screw tightening tool into contact with the screw 93 positioned in the screw hole 94 through the through hole 116, and rotate the screw 93 smoothly.

[0273] [Third Embodiment] A third embodiment will now be described. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and the descriptions of those components will be simplified or omitted.

[0274] <Impact Tools> Figure 37 is a front perspective view showing a part of the impact tool 1C according to this embodiment. Figure 38 is a longitudinal cross-sectional view showing a part of the impact tool 1C according to this embodiment. Figure 39 is a transverse cross-sectional view showing a part of the impact tool 1C according to this embodiment. Figure 40 is a cross-sectional view showing a part of the impact tool 1C according to this embodiment, corresponding to the view taken by the line XX in Figure 38. Figure 41 is a cross-sectional view showing a part of the impact tool 1C according to this embodiment, corresponding to the view taken by the line WW in Figure 38. Figure 42 is a cross-sectional view showing a part of the impact tool 1C according to this embodiment, corresponding to the view taken by the line TT in Figure 38. Figure 43 is a cross-sectional view showing a part of the impact tool 1C according to this embodiment, corresponding to the view taken by the line SS in Figure 38. Figure 44 is a cross-sectional view showing a part of the impact tool 1C according to this embodiment, corresponding to an enlarged view of a part of Figure 43. Figure 45 is a view of a part of the impact tool 1C according to this embodiment from above.

[0275] The impact tool 1C comprises a housing 202 having a motor housing 217 and an output assembly 4C.

[0276] The output assembly 4C comprises a hammer case 223, a bearing box 224, and a cover 119. The hammer 75 and spindle 26 are arranged in the internal space of the output assembly 4C defined by the hammer case 223 and the bearing box 224. The hammer case 223 holds the hammer 75 via a hammer bearing 30. The hammer 75 is connected to the hammer case 223 via the hammer bearing 30. The bearing box 224 holds the spindle 26 via a spindle bearing 27. The spindle 26 is connected to the bearing box 224 via the spindle bearing 27.

[0277] In this embodiment, the hammer case 223 is coupled to the bearing box 224 via a threaded portion. The hammer case 223 is rotatable with respect to the bearing box 224. A threaded groove 120 is formed at the rear portion of the inner peripheral surface of the hammer case 223. A thread 121 is formed on the outer peripheral surface of the bearing box 224. The threaded groove 120 and the thread 121 are coupled. When the hammer case 223 rotates with respect to the bearing box 224, the hammer case 223 moves in the front - rear direction with respect to the bearing box 224.

[0278] The cover 119 is arranged to cover the hammer case 223. An operator can rotate the hammer case 223 while holding the cover 119. By rotating the hammer case 223 via the cover 119, the operator can move the hammer case 223 in the front - rear direction with respect to the bearing box 224.

[0279] As shown in FIG. 41, the output assembly 4C has a first anti - rotation mechanism 228 that suppresses the relative rotation between the motor housing portion 217 and the bearing box 224. In this embodiment, the first anti - rotation mechanism 228 includes a convex portion 222 that protrudes radially outward from the outer peripheral surface of the bearing box 224 and a concave portion 225 provided on the inner peripheral surface of the motor housing portion 217. When the convex portion 222 is disposed in the concave portion 225, the relative rotation between the motor housing portion 217 and the bearing box 224 is suppressed.

[0280] As shown in FIG. 42, the output assembly 4C has a second anti - rotation mechanism 229 that suppresses the relative rotation between the cover 119 and the hammer case 223. In this embodiment, the second anti - rotation mechanism 229 includes a convex portion 124 that protrudes radially outward from the outer peripheral surface of the hammer case 223 and a concave portion 125 provided on the inner peripheral surface of the cover 119. When the convex portion 124 is disposed in the concave portion 125, the relative rotation between the cover 119 and the hammer case 223 is suppressed.

[0281] The second anti-rotation mechanism 229 suppresses relative rotation between the cover 119 and the hammer case 223, allowing the operator to rotate the hammer case 223 via the cover 119. The first anti-rotation mechanism 228 suppresses relative rotation between the motor housing 217 and the bearing box 224, allowing the operator to rotate the hammer case 223 relative to the bearing box 224.

[0282] As shown in Figures 43 and 44, the output assembly 4C has a positioning mechanism 231 for positioning the cover 119 in the circumferential direction. The positioning mechanism 231 includes a plurality of recesses 126 provided on the lower part of the cover 119 and a leaf spring 122 supported by at least a portion of the housing 202. The leaf spring 122 is supported by the housing 202 so as not to move circumferentially relative to the housing 202.

[0283] The leaf spring 122 has a protrusion 127. The protrusion 127 is positioned in the recess 126. The positioning of the protrusion 127 in the recess 126 positions the cover 119 in the circumferential direction.

[0284] As shown in Figures 37 and 45, a position mark 117 is provided on the outer circumferential surface of the cover 119. One position mark 117 is provided on the outer circumferential surface of the cover 119. The position mark 117 indicates the position of the cover 119 in the rotational direction. An indicator mark 118 is provided on the outer circumferential surface of the motor housing 217. Multiple indicator marks 118 are provided in the circumferential direction. In the circumferential direction, the spacing between the multiple recesses 126 and the spacing between the indicator marks 118 coincide. The indicator mark 118 indicates the amount of compression of the elastic member 78.

[0285] As the hammer case 223 is rotated by the operator via the cover 119 and moves in the front-rear direction, the hammer 75, which is connected to the hammer case 223 via the hammer bearing 30, moves with the hammer case 223 in the front-rear direction. The front end of the elastic member 78 contacts at least a portion of the hammer 75, and the rear end of the elastic member 78 contacts the cam ring 76. The cam ring 76 is connected to the flange portion 65 of the spindle 26, and the spindle 26 is connected to the bearing box 224 via the spindle bearing 27. Therefore, as the hammer 75 moves in the front-rear direction due to the rotation of the hammer case 223, the amount of compression of the elastic member 78 changes. As the hammer case 223 is rotated so that the hammer 75 moves backward, the distance between the cam ring 76 and the hammer 75 in the front-rear direction decreases, and the elastic member 78 is compressed. As the hammer case 223 is rotated so that the hammer 75 moves forward, the distance between the cam ring 76 and the hammer 75 in the front-rear direction increases, and the elastic member 78 is stretched.

[0286] The positioning of the cover 119 in the circumferential direction is achieved by the placement of the protrusion 127 in the recess 126, thereby suppressing unnecessary rotation of the cover 119. In addition, the leaf spring 122 provides the operator with a click sensation when the cover 119 is rotated. The operator rotates the cover 119 so that any of the multiple indicator marks 118 aligns with the position mark 117. Since the spacing between the multiple recesses 126 matches the spacing between the indicator marks 118, when the cover 119 is rotated so that any of the indicator marks 118 aligns with the position mark 117, the protrusion 127 is positioned in the desired recess 126, and the amount of compression of the elastic member 78 is adjusted.

[0287] <Effects> As described above, in this embodiment, the impact tool 1C may include a bearing box 224 for holding the spindle 26 and a hammer case 223 for holding the hammer 75. The hammer case 223 may be coupled to the bearing box 224 via a threaded portion including a screw groove 120 and a screw thread 121. The elastic force of the elastic member 78 may be adjusted by rotating the hammer case 223 relative to the bearing box 224 and moving it axially.

[0288] In the above configuration, the operator can adjust the elastic force of the elastic member 78 by grasping the hammer case 223 by hand and rotating it. The operator can adjust the elastic force of the elastic member 78 without using a screw tightening tool.

[0289] In this embodiment, the impact tool 1C may include a motor housing 217 that houses the motor 6, and a first anti-rotation mechanism 228 that suppresses relative rotation between the motor housing 217 and the bearing box 224.

[0290] In the above configuration, when the hammer case 223 is rotated, the first anti-rotation mechanism 228 suppresses the rotation of the bearing box 224, so that the operator can smoothly rotate the hammer case 223 relative to the bearing box 224.

[0291] In this embodiment, the impact tool 1C may include a cover 119 that covers the hammer case 223, and a second anti-rotation mechanism 229 that suppresses relative rotation between the cover 119 and the hammer case 223. The hammer case 223 may rotate via the cover 119.

[0292] In the above configuration, the second anti-rotation mechanism 229 suppresses relative rotation between the cover 119 and the hammer case 223. Therefore, the operator can rotate the hammer case 223 by grasping the cover 119 with their hand and rotating it. The rotation of the hammer case 223 adjusts the elastic force of the elastic member 78. The operator can adjust the elastic force of the elastic member 78 without directly touching the hammer case 223.

[0293] In this embodiment, the impact tool 1C may include a positioning mechanism 231 for positioning the cover 119 in the circumferential direction.

[0294] In the above configuration, unnecessary rotation of the hammer case 223 and cover 119 is suppressed.

[0295] [Fourth Embodiment] A fourth embodiment will now be described. In the following description, components that are the same as or equivalent to those in the embodiments described above will be denoted by the same reference numerals, and the descriptions of those components will be simplified or omitted.

[0296] <Output Assembly> Figure 46 is a front perspective view showing a part of the output assembly 4D according to this embodiment. Figure 47 is a longitudinal cross-sectional view showing the output assembly 4D according to this embodiment. Figure 48 is a cross-sectional view showing a part of the output assembly 4D according to this embodiment, corresponding to the view taken along the line LL in Figure 47. Figure 49 is a cross-sectional view showing a part of the output assembly 4D according to this embodiment, corresponding to the view taken along the line MM in Figure 47.

[0297] The output assembly 4D includes a hammer case 23 and a bearing box 24. The hammer 375 and the elastic member 378 are arranged in the internal space of the output assembly 4D defined by the hammer case 23 and the bearing box 24. Note that in Figure 46, the hammer case 23 is not shown, and the hammer 375 is indicated by dashed lines.

[0298] Similar to the embodiments described above, the elastic member 378 is positioned in a closed space defined by the spindle shaft portion 64, the hammer 75, and the cam ring 76. The spring constant of the elastic member 378 is 100 [N / mm] or more. The upper limit of the spring constant of the elastic member 378 is not particularly limited, but in this embodiment, the spring constant of the elastic member 378 is 10,000 [N / mm] or less.

[0299] The hammer 375 has a rear outer cylinder portion 381, a front outer cylinder portion 382, ​​and an inner cylinder portion 383. The rear outer cylinder portion 381, the front outer cylinder portion 382, ​​and the inner cylinder portion 383 are each arranged to surround the rotation axis AX. The rear outer cylinder portion 381, the front outer cylinder portion 382, ​​and the inner cylinder portion 383 are integrally formed.

[0300] The front outer cylinder portion 382 is positioned in front of the rear outer cylinder portion 381. The front end of the rear outer cylinder portion 381 is connected to the rear end of the front outer cylinder portion 382. The outer diameter of the rear outer cylinder portion 381 is larger than the outer diameter of the front outer cylinder portion 382. The inner diameter of the rear outer cylinder portion 381 is larger than the inner diameter of the front outer cylinder portion 382.

[0301] The inner cylinder portion 383 is positioned radially inward from the rear outer cylinder portion 381 and the front outer cylinder portion 382. The front end of the inner cylinder portion 383 is connected to the rear end of the front outer cylinder portion 382.

[0302] In this embodiment, the elastic member 378 includes a plurality of coil springs 391 arranged around the rotation axis AX of the spindle 26. The front ends of the coil springs 391 contact a support surface 390 between the front end of the inner circumferential surface of the rear outer cylinder portion 381 and the front end of the outer circumferential surface of the inner cylinder portion 383. The support surface 390 is positioned in front of the flange portion 65 and the cam ring 76. The rear ends of the coil springs 391 contact the front surface of the cam ring 76.

[0303] A support pin 128 is positioned inside the coil spring 391. The support pin 128 is fixed to the hammer 375. In this embodiment, the support pin 128 is press-fitted into a recess 385 provided in the support surface 390. By positioning the support pin 128 inside the coil spring 391, the coil spring 391 is positioned in both the radial and circumferential directions.

[0304] The tool holding shaft 31 movably supports the movable anvil 333. In this embodiment, the movable anvil 333 has a cylindrical portion 333A and a pin portion 333B positioned inside the cylindrical portion 333A. The front end of the pin portion 333B protrudes forward from the front end surface of the cylindrical portion 333A. The rear end of the pin portion 333B protrudes forward from the rear end surface of the cylindrical portion 333A.

[0305] <Effects> As described above, in this embodiment, the elastic member 378 may include a plurality of coil springs 391 arranged around the rotation axis of the spindle 26.

[0306] In the above configuration, the elastic member 378 can generate a high elastic force.

[0307] In this embodiment, the front end of the coil spring 391 may be in contact with the support surface 390 of the hammer 375.

[0308] In the above configuration, the front end of the coil spring 391 is stably connected to the hammer 375.

[0309] In this embodiment, the output assembly 4D may include a support pin 128 located inside the coil spring 391. The support pin 128 may be fixed to the hammer 375.

[0310] In the above configuration, the coil spring 391 is positioned in both the radial and circumferential directions.

[0311] [Other embodiments] In the above embodiment, the impact tool is assumed to be an impact driver. The impact tool may also be an impact wrench.

[0312] In the embodiment described above, the power source for the impact tool does not have to be the battery pack 20, but may also be a commercial power supply (AC power supply). [Explanation of symbols]

[0313] 1…Impact tool, 1B…Impact tool, 1C…Impact tool, 2…Housing, 3…Rear cover, 4…Output assembly, 4B…Output assembly, 4C…Output assembly, 4D…Output assembly, 5…Battery mounting section, 6…Motor, 7…Fan, 8…Controller, 9…Trigger lever, 10…Forward / reverse rotation switch, 11…Interface section, 12…Mode switch, 13…Light, 14…Left housing, 15…Right housing, 16…Housing screws, 17…Motor housing section, 18…Grip section, 19…Battery holder section, 20…Battery pack, 21 ...Intake port, 22...Exhaust port, 23...Hammer case, 24...Bearing box, 25...Reduction mechanism, 26...Spindle, 27...Spindle bearing, 28...Impact mechanism, 29...Elastic force adjustment mechanism, 30...Hammer bearing, 31...Tool holding shaft, 32...Shaft bearing, 33...Movable anvil, 34...Tool holding mechanism, 35...Stator, 36...Rotor, 37...Stator core, 38...Front insulator, 39...Rear insulator, 40...Coil, 41...Rotor core, 42...Rotor shaft, 43...Rotor magnet, 44...Sensor magnet, 45...Sensor board, 46...Rotor 47...Rotor bearing, 48...Pinion gear, 49...Bush, 50...Circuit board, 51...Case, 52...Operation button, 53...Large cylinder part, 54...Small cylinder part, 55...Ring part, 56...Rear plate part, 57...Protrusion, 58...Planetary gear, 59...Pin, 60...Internal gear, 61...O-ring, 62...Protrusion, 63...Recess, 64...Spindle shaft part, 65...Flange part, 66...Pin support part, 67...Connecting part, 68...Protrusion, 69...Spindle projection, 70...Ball groove, 71...Spindle groove, 72...Support recess, 73...Support hole, 74...Washer, 75...Hammer , 76...cam ring, 77...ball, 78...elastic member, 79...washer, 80...rotating ball, 81...rear outer cylinder part, 82...front outer cylinder part, 83...inner cylinder part, 84...hammer projection part, 85...ball groove, 86...guide groove, 87...cam slide part, 88...cam groove, 89...recess, 90...support surface, 91...disc spring, 92...annular groove, 93...screw, 94...screw hole, 95...front end surface, 96...opposing surface, 97...tool holding part, 98...anvil part, 99...tool hole, 100...recess, 101...inner circumferential surface, 102...opposing surface, 103...outer circumferential surface, 104...anvil hole, 105...support recess, 106...support ball,107...O-ring, 108...Restraining member, 109...Groove, 110...Retaining ball, 111...Leaf spring, 112...Sleeve, 113...Coil spring, 114...Positioning member, 115...Support recess, 116...Through hole, 117...Position mark, 118...Indicator mark, 119...Cover, 120...Screw groove, 121...Screw thread, 122...Leaf spring, 123...Hammer case, 12 4...Convex part, 125...Concave part, 126...Concave part, 127...Convex part, 128...Support pin, 130A...First hammer bearing, 130B...Second hammer bearing, 153...Large cylinder part, 154...Small cylinder part, 155...Front, 175...Hammer, 181...Rear outer cylinder part, 181A...Front small diameter part, 181B...Large diameter part, 181C...Rear small diameter part, 181D...Notch, 182...Front outer cylinder part, 183...Inner cylinder part, 1 96...Rear surface, 197...Support surface, 202...Housing, 217...Motor housing, 222...Protrusion, 223...Hammer case, 224...Bearing box, 225...Recess, 228...First anti-rotation mechanism, 229...Second anti-rotation mechanism, 231...Positioning mechanism, 331...First movable anvil, 332...Second movable anvil, 333...Movable anvil, 333A...Cylindrical part, 333B...Pin part, 3 75...hammer, 378...elastic member, 381...rear outer cylinder, 382...front outer cylinder, 383...inner cylinder, 385...recess, 390...support surface, 391...coil spring, 691...first spindle projection, 692...second spindle projection, 841...first hammer projection, 842...second hammer projection, 711...first part, 712...second part, 881...third part, 882...fourth part, AX...rotating shaft.

Claims

1. A motor; a spindle having a spindle shaft portion and a flange portion provided at a rear portion of the spindle shaft portion, the spindle being rotated by a torque of the motor; a tool holder shaft, at least a portion of which is disposed forward of the spindle; a hammer supported on the spindle shaft portion and configured to strike the tool holding shaft in a rotational direction; an elastic member disposed between a front surface of the flange portion and a support surface of the hammer disposed forward of the flange portion in the axial direction; an elastic force adjustment mechanism that adjusts the elastic force of the elastic member in an initial state before the motor is started. Impact tool.

2. The elastic force adjustment mechanism adjusts the compression amount of the elastic member in the initial state.

2. The impact tool according to claim 1.

3. The rear end of the elastic member is supported by the flange portion, The elastic force adjustment mechanism adjusts the compression amount by moving a position of a front end of the elastic member.

3. An impact tool according to claim 2.

4. the elastic force adjustment mechanism has a screw that is disposed in a screw hole formed in the hammer and is connected to a front end of the elastic member, The amount of compression is adjusted by rotating the screw.

4. An impact tool according to claim 3.

5. a washer for supporting a front end of the elastic member; The rear end of the screw contacts the front surface of the washer; The screw is connected to the elastic member via the washer.

5. An impact tool according to claim 4.

6. The screw holes are formed at intervals around the rotation axis of the hammer, The screws are disposed in the plurality of screw holes, one for each screw.

5. An impact tool according to claim 4.

7. the hammer has an inner cylinder portion disposed around the spindle shaft portion, a front outer cylinder portion disposed radially outward and forward of the inner cylinder portion, and a rear outer cylinder portion disposed radially outward of the front outer cylinder portion and rearward of the front outer cylinder portion, The screw hole is formed to penetrate through the front end surface of the rear outer cylinder portion and the support surface.

5. An impact tool according to claim 4.

8. a hammer case that houses the hammer; A hammer bearing is held in the hammer case and rotatably supports the hammer, The hammer bearing is disposed around the front outer cylinder portion. An impact tool according to claim 7.

9. A hammer case is provided to house the hammer, the hammer case has a through hole overlapping with the screw hole in both a radial direction and a circumferential direction, The screw is rotated through the through hole.

8. An impact tool according to claim 7.

10. a hammer bearing that is held by the hammer case and rotatably supports the hammer; The hammer bearing is disposed around the rear outer cylinder portion.

10. An impact tool according to claim 9.

11. A bearing box for holding the spindle; A hammer case for holding the hammer, The hammer case is connected to the bearing box via a screw portion, The elastic force of the elastic member is adjusted by rotating the hammer case relative to the bearing box and moving it in the axial direction.

2. The impact tool according to claim 1.

12. a motor housing portion that houses the motor; a first anti-rotation mechanism that suppresses relative rotation between the motor accommodating portion and the bearing box; An impact tool according to claim 11.

13. A cover for covering the hammer case; a second anti-rotation mechanism that suppresses relative rotation between the cover and the hammer case, The hammer case is rotated via the cover. An impact tool according to claim 11.

14. a positioning mechanism for positioning the cover in a circumferential direction; 14. An impact tool according to claim 13.

15. The elastic member includes a disc spring.

2. The impact tool according to claim 1.

16. a washer for supporting a front end of the elastic member; The front end of the elastic member is connected to the hammer via the washer.

16. An impact tool according to claim 15.

17. a movable anvil movably supported on the tool holding shaft; The hammer strikes the movable anvil in a rotational direction without being displaced in an axial direction.

2. The impact tool according to claim 1.

18. the movable anvil moves so as to change between a first state in which at least a portion of the movable anvil protrudes radially outward from an outer circumferential surface of the tool holder shaft and a second state in which the movable anvil is disposed radially inward from the outer circumferential surface of the tool holder shaft; The hammer strikes the movable anvil in the first state and rotates around the spindle shaft portion in the second state.

18. An impact tool according to claim 17.

19. a cam ring connected to the flange portion via a ball so as to be relatively rotatable, and connected to the hammer so as to be relatively movable in the axial direction but not rotatable relative thereto; The cam ring is disposed to face a front surface of the flange portion, The elastic member is disposed between the front surface of the cam ring and the support surface of the hammer in the axial direction.

18. An impact tool according to claim 17.

20. The cam ring is connected to a rear portion of the hammer, The elastic member is disposed in a closed space defined by the spindle shaft portion, the hammer, and the cam ring.

20. An impact tool according to claim 19.

Images