Impact tools

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]

[0001] The technology disclosed herein relates to impact tools. [Background technology]

[0002] BACKGROUND ART In the technical field related to impact tools, an impact tool such as that disclosed in Patent Document 1 is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2015-033738 Summary of the Invention [Problem to be solved by the invention]

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

[0006] This specification discloses an impact tool, which may include a motor, a spindle having a spindle shaft and a flange provided at a rear portion of the spindle shaft and rotated by a rotational force of the motor, a tool holder shaft with at least a portion disposed forward of the spindle, a hammer supported on the spindle shaft and striking the tool holder shaft in the rotational direction, an elastic member disposed axially between a front surface of the flange and a support surface of the hammer disposed forward of the flange, and an elastic force adjustment mechanism that adjusts the elastic force of the elastic member in an initial state before the motor is started. [Effects of the Invention]

[0007] According to the technology disclosed in this specification, an impact tool that can smoothly perform both high-load work and low-load work is provided. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front perspective view showing an impact tool according to a first embodiment. [Figure 2] FIG. 2 is a side view showing the impact tool according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing the impact tool according to the first embodiment. [Figure 4] FIG. 4 is a front perspective view of the output assembly according to the first embodiment. [Figure 5] FIG. 5 is a vertical cross-sectional view showing the output assembly according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing the output assembly according to the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing the output assembly according to the first embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing the output assembly according to the first embodiment. [Figure 9] FIG. 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 parts of the output assembly according to the first embodiment. [Figure 14] FIG. 14 is an exploded perspective view from the rear showing the main parts of the output assembly according to the first embodiment. [Figure 15] FIG. 15 is a front perspective view showing the spindle according to the first embodiment. [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 as seen from the front. [Figure 18] FIG. 18 is a front perspective view 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 as seen from behind. [Figure 20] FIG. 20 is a cross-sectional view showing the cam ring according to the first embodiment. [Figure 21] FIG. 21 is a front perspective view showing the tool holder shaft according to the first embodiment. [Figure 22] FIG. 22 is a cross-sectional view showing the tool holder 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. [Figure 27] FIG. 27 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 28] FIG. 28 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 29] FIG. 29 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 30] FIG. 30 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 31] FIG. 31 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 32] FIG. 32 is a cross-sectional view showing the operation of the output assembly according to the first embodiment. [Figure 33] FIG. 33 is a perspective view of a part of the impact tool according to the second embodiment, seen from the front. [Figure 34] FIG. 34 is a front perspective view of the output assembly according to the second embodiment. [Figure 35] FIG. 35 is a vertical cross-sectional view showing an output assembly according to the second embodiment. [Figure 36] FIG. 36 is an exploded perspective view showing an output assembly according to the second embodiment. [Figure 37] FIG. 37 is a perspective view of a part of the impact tool according to the third embodiment, seen from the front. [Figure 38] FIG. 38 is a vertical cross-sectional view showing a part of the impact tool according to the third embodiment. [Figure 39] FIG. 39 is a cross-sectional view showing a part of the impact tool according to the third embodiment. [Figure 40] FIG. 40 is a cross-sectional view showing a part of the impact tool according to the third embodiment. [Figure 41] FIG. 41 is a cross-sectional view showing a part of the impact tool according to the third embodiment. [Figure 42] FIG. 42 is a cross-sectional view showing a part of the impact tool according to the third embodiment. [Figure 43]FIG. 43 is a cross-sectional view showing a part of the impact tool according to the third embodiment. [Figure 44] FIG. 44 is a cross-sectional view showing a part of the impact tool according to the third embodiment. [Figure 45] FIG. 45 is a view of a part of the impact tool according to the third embodiment seen from above. [Figure 46] FIG. 46 is a front perspective view of a portion of an output assembly according to a fourth embodiment. [Figure 47] FIG. 47 is a vertical cross-sectional view showing an output assembly according to the fourth embodiment. [Figure 48] FIG. 48 is a cross-sectional view showing a portion of an output assembly according to a fourth embodiment. [Figure 49] FIG. 49 is a cross-sectional view showing a portion of an output assembly according to a fourth embodiment. DETAILED DESCRIPTION OF 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 rotated by the rotational force of the motor, a tool holder shaft with at least a portion thereof positioned forward of the spindle, a hammer supported on the spindle shaft portion and striking the tool holder shaft in the rotational direction, an elastic member positioned axially between the front surface of the flange portion and a support surface of the hammer positioned forward of the flange portion, and an elastic force adjustment mechanism that adjusts the elastic force of the elastic member in an initial state before the motor is started.

[0010] In the above configuration, the elastic force of the elastic member is adjustable, so that the impact tool can smoothly perform both high-load work and low-load work. When low-load work is being performed, the elastic force of the elastic member is adjusted to be low, and when high-load work is being performed, the elastic force of the elastic member is adjusted to be high, so that the impact tool can smoothly perform both high-load work and low-load work.

[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 compression amount of the elastic member in the initial state. When the compression amount is small, the elastic force of the elastic member is low, and when the compression amount is large, the elastic force of the elastic member is high.

[0013] In one or more embodiments, the rear end of the elastic member may be supported by a flange portion, and 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 position of the rear end of the elastic member is fixed, and the position of the front end of the elastic member is moved, thereby adjusting the compression amount.

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

[0016] In the above configuration, when the screw is rotated while placed in the screw hole, the screw moves in the front-to-rear direction, thereby adjusting the compression amount.

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

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

[0019] In one or more embodiments, a plurality of screw holes may be formed at intervals around the rotation axis of the hammer, and one screw may be disposed in each of the plurality of screw holes.

[0020] In the above configuration, by adjusting the positions of the multiple screws in the front-to-rear direction, the compression amount of the elastic member and the tilt angle of the elastic member relative to the spindle are adjusted. The tilt angle of the elastic member relative to the spindle refers to the angle between the rotation axis of the spindle and the rotation axis (center axis) of the elastic member.

[0021] In one or more embodiments, the hammer may have an inner cylindrical portion disposed around the spindle shaft portion, a front outer cylindrical portion disposed radially outward and forward of the inner cylindrical portion, and a rear outer cylindrical portion disposed radially outward and rearward of the front outer cylindrical portion. The threaded hole may be formed to pass through a front end surface of the rear outer cylindrical portion and the support surface.

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

[0023] In one or more embodiments, the impact tool may include a hammer case that houses the hammer, and a hammer bearing that is held in the hammer case and rotatably supports the hammer. The hammer bearing may be disposed around the front outer cylindrical portion.

[0024] In the above configuration, after the adjustment of the elastic force by the screw is completed, the hammer bearing is positioned so as to cover the front end of the screw hole, thereby protecting the screw.

[0025] In one or more embodiments, the impact tool may include a hammer case that houses a hammer. The hammer case may have through holes that overlap with the screw holes in both the radial and circumferential directions. The screw may be rotated through the through holes.

[0026] With the above configuration, the worker can smoothly bring the screw tightening tool into contact with the screw placed in the screw hole through the through hole, allowing the worker to smoothly rotate the screw. The worker can also adjust the elastic force of the elastic member as appropriate depending on the type of work.

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

[0028] In the above configuration, the front end of the screw hole is not covered by the hammer bearing, so the worker can smoothly bring the screw tightening tool into contact with the screw placed in the screw hole through the through hole, allowing the screw to be rotated smoothly.

[0029] In one or more embodiments, the impact tool may include a bearing box that holds the spindle and a hammer case that holds the hammer. The hammer case may be coupled to the bearing box via a threaded portion. The hammer case may be rotated relative to the bearing box to move axially, thereby adjusting the elastic force of the elastic member.

[0030] With the above configuration, the worker can adjust the elastic force of the elastic member by gripping and rotating the hammer case with his or her hand, without using a screw tightening tool.

[0031] In one or more embodiments, the impact tool may include a motor housing that houses the motor, and a first anti-rotation mechanism that restricts 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 prevents the bearing box from rotating, 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 covers the hammer case, and a second anti-rotation mechanism that prevents relative rotation between the cover and the hammer case. The hammer case may be rotated via the cover.

[0034] In the above configuration, the second anti-rotation mechanism prevents the cover and the hammer case from rotating relative to each other, so the worker can rotate the hammer case by gripping and rotating the cover with his or her hand. By rotating the hammer case, the elastic force of the elastic member is adjusted. The worker 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 circumferentially positioning the cover.

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

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

[0038] The above configuration prevents the impact tool from becoming larger. When a predetermined elastic force is required from the elastic member, using a disc spring allows the axial dimension of the elastic member to be shorter than, for example, using a coil spring. This allows the hammer to strike the tool holder shaft in the rotational direction while preventing the impact tool from becoming larger. In particular, the axial length of the impact tool is shortened. When the impact tool has a motor housing, a rear cover disposed at the rear end of the motor housing, and an output assembly disposed 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 a front end of the resilient member, which 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 the washer.

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

[0042] In the above configuration, the movable anvil is movably supported on the tool holder shaft, so the hammer can strike the movable anvil in the rotational direction without axial displacement, and since the hammer does not displace axially, the generation of axial vibrations in the impact tool is suppressed.

[0043] In one or more embodiments, the movable anvil may move between a first state in which at least a portion of the movable anvil protrudes radially outward from the outer circumferential surface of the tool holder shaft and a second state in which the movable anvil is positioned radially inward from the outer circumferential surface of the tool holder 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 that is rotatably connected to the flange portion via a ball and that is axially movable but non-rotatably connected to the hammer. The cam ring may be disposed to face a front surface of the flange portion. The elastic member may be disposed axially between the front surface of the cam ring and a support surface of the hammer.

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

[0047] In one or more embodiments, the cam ring may be coupled to a rear portion of the hammer. The resilient member may be disposed in an enclosed space defined by the spindle shaft portion, the hammer, and the cam ring.

[0048] In the above configuration, when the hammer strikes the tool holder shaft in the rotational direction via the movable anvil, the cam ring and the elastic member rotate together with the hammer. That is, when the hammer strikes the tool holder 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 holder shaft. As a result, the tool holder shaft is struck with a high striking force.

[0049] Hereinafter, embodiments will be described with reference to the drawings. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0050] In the embodiment, the positional relationship of each part is described using the terms left, right, front, rear, top, and bottom. These terms indicate relative positions or directions based on the center of the impact tool. The impact tool has a motor 6 as a power source.

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

[0052] A direction or position away from the center of the impact tool in a specified direction in the axial direction is appropriately referred to as "one axial side," and the opposite side of the one axial side is appropriately referred to as "the other axial side." A specified direction in the circumferential direction is appropriately referred to as "one circumferential side," and the opposite side of the one circumferential side is appropriately referred to as "the other circumferential side." A direction or position away from the rotation axis AX in the radial direction is appropriately referred to as "the radially outer side," and the opposite side of the radially outer side is appropriately referred to as "the radially inner side."

[0053] In the embodiment, the axial direction and the front-rear direction coincide with each other. One side in the axial direction may be considered to be the front. The other side in the axial direction may be considered to be the rear.

[0054] [First embodiment] A first embodiment will be described.

[0055] <Outline of impact tools> Fig. 1 is a front perspective view showing the impact tool 1 according to this embodiment. Fig. 2 is a side view showing the impact tool 1 according to this embodiment. Fig. 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 includes 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 lever 10, an interface section 11, a mode switch 12, and a light 13.

[0057] The housing 2 accommodates 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 is composed of a pair of half housings. The housing 2 includes a left housing 14 and a right housing 15 located to the right of the left housing 14. The left housing 14 and the right housing 15 are fixed together by a plurality of housing screws 16.

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

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

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

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

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

[0063] The motor accommodating section 17 has an air intake port 21. The rear cover 3 has an air 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 to the external space of the housing 2 through the air exhaust port 22.

[0064] The output assembly 4 is disposed forward of the motor 6. The output assembly 4 has 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 arranged forward of the motor accommodating portion 17. The hammer case 23 is cylindrical. The bearing box 24 is fixed to the rear end of the hammer case 23. The bearing box 24 and the rear portions of the hammer case 23 are arranged inside the motor accommodating portion 17. The rear portions of the bearing box 24 and the hammer case 23 are sandwiched between the left housing 14 and the right housing 15. The bearing box 24 and the hammer case 23 are each fixed to the motor accommodating portion 17.

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

[0067] A battery pack 20 is attached to the battery attachment section 5. The battery attachment section 5 is disposed below the battery holding section 19. The battery pack 20 is detachable from the battery attachment section 5. The battery pack 20 functions as a power source for the impact tool 1. The battery pack 20 is attached to the battery attachment section 5 by being inserted into the battery attachment section 5 from the front of the battery holding section 19. The battery pack 20 is removed from the battery attachment section 5 by being pulled forward from the battery attachment section 5. The battery pack 20 includes a secondary battery. In this embodiment, the battery pack 20 includes a rechargeable lithium-ion battery. When attached to the battery attachment 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] The motor 6 is a power source for the impact tool 1. The motor 6 is an electric motor that is driven based on power supplied from the battery pack 20. The motor 6 is an inner rotor type brushless motor. The motor 6 has a stator 35 and a rotor 36. The stator 35 is supported by the motor housing portion 17. At least a portion of the rotor 36 is disposed 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 disposed radially outward of the rotor 36. The stator core 37 includes a plurality of stacked steel plates. The steel plates are metal plates whose main component is iron. The stator core 37 is cylindrical. The stator core 37 has a plurality of teeth that support the coils 40.

[0071] The front insulator 38 is fixed to the front portion of the stator core 37. The rear insulator 39 is fixed to the rear portion of the stator core 37. The front insulator 38 and the rear insulator 39 are each an electrical insulating member made of synthetic resin. The front insulator 38 is arranged so as to cover part of the surface of the teeth. The rear insulator 39 is arranged so as to cover part of the surface of the teeth.

[0072] The coil 40 is attached to the stator core 37 via the front insulator 38 and the 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. The multiple coils 40 are connected to each other via short-circuit members.

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

[0074] The rotor core 41 and the 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 disposed radially inward of the rotor core 41. The front portion of the rotor shaft 42 protrudes forward from the front end surface of the rotor core 41. The rear portion of the rotor shaft 42 protrudes rearward from the rear end surface of the rotor core 41.

[0075] The rotor magnet 43 is fixed to the rotor core 41. The rotor magnet 43 has a cylindrical shape. 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 has an annular shape. The sensor magnet 44 is disposed 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 with 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 position of the sensor magnet 44, thereby detecting the position of the rotor 36 in the rotational direction.

[0078] The rear portion of the rotor shaft 42 is rotatably supported by a rotor bearing 46. The front portion of the rotor shaft 42 is rotatably supported by a rotor bearing 47. The rotor bearing 46 is held by the rear cover 3. The rotor bearing 46 is held by the bearing box 24. The front end portion of the rotor shaft 42 is disposed in the internal space of the output assembly 4 through the opening of 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 part of the reduction mechanism 25. The rotor shaft 42 is connected to the reduction mechanism 25 via the pinion gear 48.

[0080] The fan 7 generates an airflow for cooling the motor 6. The fan 7 is disposed rearward of the motor 6. The fan 7 is disposed between the rotor bearing 46 and the stator 35. The fan 7 is fixed to at least a portion of the rotor 36. The fan 7 is fixed to the rear of the rotor shaft 42 via a bushing 49. The fan 7 rotates with the rotation of the rotor 36. As the rotor shaft 42 rotates, the fan 7 rotates together with the rotor shaft 42. As the fan 7 rotates, air from the external space of the housing 2 flows into the internal space of the housing 2 through the air intake 21. The air that has flowed into the internal space of the housing 2 cools the motor 6 by circulating through the internal space of the housing 2. As the fan 7 rotates, the air that has circulated through the internal space of the housing 2 flows out into the external space of the housing 2 through the air exhaust 22.

[0081] The controller 8 outputs a control signal to control the motor 6. The controller 8 is housed in the battery holding section 19. The controller 8 switches the control mode of the motor 6 based on the work content of the impact tool 1. The control mode of the motor 6 refers to a 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), a non-volatile memory such as a ROM (Read Only Memory) or storage, a volatile memory such as a RAM (Random Access Memory), a transistor, and a resistor.

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

[0083] The forward / reverse switching lever 10 is operated by an operator to switch the rotation direction of the motor 6. The forward / reverse switching lever 10 is provided on the upper part of the grip portion 18. By operating the forward / reverse switching lever 10, the rotation direction of the motor 6 is switched from one of the forward direction and the reverse direction to the other. By switching the rotation direction of the motor 6, the rotation direction of the spindle 26 is switched. When the forward / reverse switching lever 10 is placed in the neutral position, the trigger lever 9 cannot be operated.

[0084] The interface unit 11 has a plurality of operation buttons 52 that are operated by an operator. The interface unit 11 is provided in the battery holding unit 19. The interface unit 11 is provided on the upper surface of the battery holding unit 19, forward of the grip unit 18. When the operator operates the operation buttons 52, the operation mode of the motor 6 is switched.

[0085] The mode changeover switch 12 is operated by an operator to change the control mode of the motor 6. The mode changeover switch 12 is disposed above the trigger lever 9.

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

[0087] <Output Assembly> FIG. 4 is a front perspective view of the output assembly 4 according to the present embodiment. FIG. 5 is a longitudinal cross-sectional view of the output assembly 4 according to the present embodiment. FIG. 6 is a transverse cross-sectional view of the output assembly 4 according to the present embodiment. FIG. 7 is a cross-sectional view of the output assembly 4 according to the present embodiment, corresponding to the cross-sectional view taken along line CC in FIG. 5. FIG. 8 is a cross-sectional view of the output assembly 4 according to the present embodiment, corresponding to the cross-sectional view taken along line DD in FIG. 5. FIG. 9 is a cross-sectional view of the output assembly 4 according to the present embodiment, corresponding to the cross-sectional view taken along line EE in FIG. 5. FIG. 10 is a cross-sectional view of the output assembly 4 according to the present embodiment, corresponding to the cross-sectional view taken along line FF in FIG. 5. FIG. 11 is a cross-sectional view of the output assembly 4 according to the present embodiment, corresponding to the cross-sectional view taken along line GG in FIG. 5. FIG. 12 is an exploded perspective view of the output assembly 4 according to the present 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, the spindle 26, and the tool holder shaft 31 each rotate about a rotation axis AX. The rotation axis of the rotor 36, the rotation axis of the spindle 26, and the rotation axis of the tool holder shaft 31 are aligned. The spindle 26 and the tool holder shaft 31 each rotate due to the rotational force generated by the motor 6.

[0090] (Hammer case) The hammer case 23 has a large cylinder portion 53 and a small cylinder portion 54. The large cylinder portion 53 and the small cylinder portion 54 are each arranged to surround the rotation axis AX. The small cylinder portion 54 is arranged forward of the large cylinder portion 53. The inner diameter of the large cylinder portion 53 is larger than the inner diameter of the small cylinder portion 54. The outer diameter of the large cylinder portion 53 is larger than the outer diameter of the small cylinder portion 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 57. The ring portion 55 is arranged to surround the rotation axis AX. The ring portion 55 is inserted inside the rear end of the large cylinder 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 57 is provided on the rear surface of the rear plate portion 56. The protrusion 57 protrudes rearward from the rear surface of the rear plate portion 56. The protrusion 57 is arranged to surround the opening of the rear plate portion 56. The rear plate portion 56 and the protrusion 57 are each connected to the motor accommodating portion 17.

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

[0093] The reduction mechanism 25 has a plurality of planetary gears 58 arranged around the pinion gear 48, pins 59 supporting each of the planetary gears 58, and an internal gear 60 arranged around the planetary gears 58. Each of the 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 both the hammer case 23 and the bearing box 24. An O-ring 61 is arranged 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 protrudes 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 arranged in recesses 63 of the hammer case 23. By placing the protrusions 62 in the recesses 63, relative rotation between the hammer case 23 and the internal gear 60 is suppressed. The internal gear 60 is always unable to rotate relative to the hammer case 23.

[0095] When the rotor shaft 42 is rotated by 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 revolution of the planetary gear 58, the spindle 26 connected to the planetary gear 58 via the pin 59 rotates at a rotational speed lower than the rotational speed of the rotor shaft 42.

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

[0097] The spindle 26 rotates due to the rotational force of the motor 6. At least a portion of the spindle 26 is disposed forward of the speed reduction mechanism 25. The spindle 26 is disposed rearward of the tool holding shaft 31. The spindle 26 is rotated by the rotor 36. The spindle 26 rotates due to the rotational force of the rotor 36 transmitted by the speed 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 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 protrusion 69 is provided at the front end of the outer peripheral surface of the spindle shaft portion 64. The spindle protrusion 69 protrudes radially outward from the front end of the outer peripheral surface of the spindle shaft portion 64. Two spindle protrusions 69 are provided around the rotation axis AX. The two spindle protrusions 69 are arranged to sandwich the rotation axis AX. In the following description, one spindle protrusion 69 will be referred to as a first spindle protrusion 691, and the other spindle protrusion 69 will be referred to as a second spindle protrusion 692, as appropriate.

[0100] A ball groove 70 is formed on the outer peripheral surface of the spindle shaft portion 64. The ball groove 70 is located rearward of the spindle protrusion 69. The ball groove 70 is formed so as to surround the rotation axis AX. The ball groove 70 is formed so as to be recessed radially inward from the outer peripheral 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. A plurality of 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 disposed rearward of the flange portion 65. The pin support portion 66 is annular. A portion of the flange portion 65 and a portion of the pin support portion 66 are connected via a connecting portion 67. A protrusion 68 protrudes rearward from the pin support portion 66.

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

[0104] The protrusion 68 is disposed inside the spindle bearing 27. The protrusion 68 is rotatably supported by the spindle bearing 27. A washer 74 is disposed at a position facing the front end of the inner ring of the spindle bearing 27.

[0105] (impact 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 speed reducer 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 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 arranged around the spindle shaft portion 64. The hammer 75 is rotatably supported by the spindle shaft portion 64. The hammer 75 is arranged forward of the reduction mechanism 25.

[0108] The hammer 75 does not move axially relative to the hammer case 23. However, in reality, the hammer 75 may move slightly axially relative to the hammer case 23 due to, for example, rattle. The hammer 75 is rotatable relative to the spindle 26. The hammer 75 is supported by the spindle shaft portion 64 and is rotatable relative to 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 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 integral with each other.

[0110] The front outer cylinder portion 82 is disposed forward of the rear outer cylinder portion 81. The front end portion of the rear outer cylinder portion 81 is connected to the rear end portion 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 portion of the inner cylinder portion 83 is connected to the rear end portion of the front outer cylinder portion 82. The front outer cylinder portion 82 is positioned radially outward and forward from 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 rearward from the front outer cylinder portion 82.

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

[0113] The inner cylindrical portion 83 is disposed around the spindle shaft portion 64. The inner peripheral surface of the inner cylindrical portion 83 faces the outer peripheral surface of the spindle shaft portion 64. A ball groove 85 is formed on the inner peripheral surface of the inner cylindrical portion 83. The ball groove 85 is formed so as to surround the rotation axis AX. The ball groove 85 is formed so as to be recessed radially outward from the inner peripheral surface of the inner cylindrical portion 83.

[0114] A guide groove 86 is provided on the inner peripheral surface of the rear outer cylindrical portion 81. The guide groove 86 is formed to extend in the axial direction on the inner peripheral surface of the rear outer cylindrical portion 81. The guide groove 86 is formed to extend forward from the rear end portion of the rear outer cylindrical portion 81. A plurality of 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] Fig. 18 is a front perspective view of cam ring 76 according to this embodiment, Fig. 19 is a rear view of cam ring 76 according to this embodiment, and Fig. 20 is a cross-sectional view of cam ring 76 according to this embodiment.

[0116] The cam ring 76 is connected to the flange portion 65 via balls 77 so as to be relatively rotatable. The cam ring 76 is connected to the hammer 75 so as to be relatively movable in the axial direction but not rotatable relative to the hammer. The cam ring 76 is disposed so as to face the front surface of the flange portion 65. The cam ring 76 is connected to the rear portion of the hammer.

[0117] The cam ring 76 is disposed inside the rear outer cylindrical portion 81. The cam ring 76 and the hammer 75 are capable of relative movement in the axial direction. As described above, the hammer 75 does not move in the axial direction relative to the hammer case 23. However, in reality, the hammer 75 may move slightly in the axial direction relative to the hammer case 23 due to, for example, rattle. The cam ring 76 moves in the axial direction relative to the hammer case 23 inside the rear outer cylindrical portion 81 of the hammer 75.

[0118] Cam slide portions 87 are provided on the outer peripheral surface of the cam ring 76. The cam slide portions 87 protrude radially outward from the outer peripheral surface of the cam ring 76. A plurality of 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 arranged in the guide grooves 86. One cam slide portion 87 is arranged in one guide groove 86. The cam slide portions 87 move in the axial direction in the guide grooves 86. The cam ring 76 can move in the axial direction 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 portion that suppresses relative rotation between the hammer 75 and the cam ring 76 .

[0120] Cam grooves 88 are provided on the inner peripheral surface of the cam ring 76. A plurality of 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 disposed forward of the flange portion 65. The cam ring 76 is disposed inside the rear outer cylindrical portion 81 of the hammer 75 and faces the front surface of the flange portion 65.

[0122] The ball 77 is disposed between the spindle 26 and the cam ring 76. The ball 77 is disposed 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 balls 77 are made of a metal such as steel. The flange portion 65 has a spindle groove 71 in which at least a portion of the balls 77 are disposed. The spindle groove 71 is provided on a portion 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 balls 77 are disposed. The cam groove 88 is provided on a portion 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 balls 77 are disposed between the spindle groove 71 and the cam groove 88. As described above, three spindle grooves 71 are provided. Three cam grooves 88 are provided. Three balls 77 are provided. One ball 77 is disposed between one spindle groove 71 and one cam groove 88. The balls 77 can roll inside the spindle groove 71 and inside the cam groove 88. The cam ring 76 can move along with the balls 77.

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

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

[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 at the center of the spindle groove 71 in the circumferential direction. The first portion 711 slopes rearward from the center of the spindle groove 71 toward one side in the circumferential direction. The second portion 712 slopes rearward from the center of the spindle groove 71 toward the other side in the circumferential direction. The first portion 711 is defined between the center and one end of the spindle groove 71 in the circumferential direction. The second portion 712 is defined between the center and the other end of the spindle groove 71 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 at the center of the cam groove 88 in the circumferential direction. The third portion 881 inclines rearward from the center of the cam groove 88 toward one side in the circumferential direction. The fourth portion 882 inclines rearward from the center of the cam groove 88 toward the other side in the circumferential direction. The third portion 881 is defined between the center and one end of the cam groove 88 in the circumferential direction. The fourth portion 882 is defined between the center 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 through 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 circumferential end of the first portion 711, causing the cam ring 76 to receive force from the ball 77 and move forward.

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

[0130] During the relative rotation between the flange portion 65 and the cam ring 76, the ball 77 moves through 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, causing the cam ring 76 to receive force from the ball 77 and move forward.

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

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

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

[0134] The elastic member 78 constantly generates an elastic force that moves the cam ring 76 rearward. In the axial direction, the elastic member 78 is disposed between the hammer 75 and the cam ring 76. At least a portion of the elastic member 78 is disposed 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 cylindrical portion 81, the outer circumferential surface of the inner cylindrical portion 83, and a support surface 90 disposed forward of the flange portion 65 and the cam ring 76. The support surface 90 is disposed to connect the front end of the inner circumferential surface of the rear outer cylindrical portion 81 and the front end of the outer circumferential surface of the inner cylindrical portion 83. The support surface 90 is annular. At least a portion of the elastic member 78 is disposed inside the recess 89. In the axial direction, the elastic member 78 is disposed between the front surface of the cam ring 76 and a support surface 90 of the hammer 75 disposed forward of the flange portion 65 and the cam ring 76 .

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

[0136] In this embodiment, the spring constant of the elastic member 78 is 100 [N / mm] or more. There is no particular upper limit to the spring constant of the elastic member 78, but in this embodiment, the spring constant of the elastic member 78 is 10,000 [N / mm] or less.

[0137] The hammer 75 is disposed around the spindle shaft portion 64. The cam ring 76 is disposed forward 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. A closed space is defined by the spindle shaft portion 64, the hammer 75, and the cam ring 76. The closed space is defined by the outer peripheral surface of the spindle shaft portion 64, the outer peripheral surface of the inner cylinder portion 83, the support surface 90, the inner peripheral surface of the rear outer cylinder portion 81, and the front surface of the cam ring 76. The elastic member 78 is disposed in the closed space.

[0138] The washer 79 supports the front end of the elastic member 78. The washer 79 is arranged radially outward from the inner cylindrical portion 83. The washer 79 is annular. The washer 79 is arranged so as to surround the inner cylindrical portion 83. The washer 79 is arranged 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 arranged 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 located at the rearmost position 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 located at the frontmost position among the multiple disc springs 91 arranged in the axial direction.

[0140] The rotating ball 80 is disposed between the spindle shaft portion 64 and the hammer 75. The rotating ball 80 is disposed between the ball groove 70 and the ball groove 85. A portion of the rotating ball 80 is disposed in the ball groove 70, and a portion of the rotating ball 80 is disposed in the ball groove 85. A plurality of rotating balls 80 are disposed 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 ball 80 functions as a bearing for the hammer 75. The rotating ball 80 allows the hammer 75 and the spindle shaft portion 64 to rotate smoothly relative to each other.

[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 compression amount 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 the cam ring 76. The elastic force adjustment mechanism 29 adjusts the compression amount 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 the washer 79. The screw 93 is connected to the front end of the elastic member 78 via the washer 79. The screw 93 is disposed in a threaded hole 94 formed in the hammer 75. The threaded hole 94 is formed to penetrate a front end surface 95 of the rear outer cylinder portion 81 and the support surface 90. In a plane perpendicular to the rotation axis AX, the front end surface 95 has an annular shape. The front end surface 95 faces forward. A plurality of threaded holes 94 are formed at intervals around the rotation axis AX of the hammer 75. One screw 93 is disposed in each of the plurality of threaded holes 94. In this embodiment, six threaded holes 94 are formed at intervals around the rotation axis AX. One screw 93 is disposed in each of the six threaded holes 94.

[0144] The rear end of the screw 93 contacts the front surface of the washer 79. Rotation of the screw 93 adjusts the compression amount of the elastic member 78. Rotation of the screw 93 in one direction causes the screw 93 to move rearward relative to the hammer 75. The rearward movement of the screw 93 causes the front end of the elastic member 78 to move rearward 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 front end of the elastic member 78 moves rearward, compressing the elastic member 78. Rotation of the screw 93 in the other direction causes the screw 93 to move 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 front end of the elastic member 78 moves forward, expanding the elastic member 78.

[0145] The compression amount of the elastic member 78 is adjusted during the assembly of the impact tool 1. After the spindle 26, the hammer 75, and the cam ring 76 are connected so that the elastic member 78 is disposed in the closed space defined by the spindle shaft portion 64, the hammer 75, and the cam ring 76, a screw tightening tool is inserted into the screw hole 94 from the front of the front end surface 95. The tip of the screw tightening tool is inserted into the tool hole of the screw 93 via the screw hole 94. The assembler can adjust the compression amount of the elastic member 78 by rotating the screw 93 using the screw tightening tool. Furthermore, the inclination angle of the elastic member 78 with respect 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 arranged 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 arranged around the front outer cylindrical 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 cylindrical 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 between them. The hammer bearing 30 is a ball bearing. The outer ring of the hammer bearing 30 contacts the inner circumferential surface of the large cylindrical portion 53 of the hammer case 23. The inner ring of the hammer bearing 30 contacts the outer peripheral surface of the front outer cylindrical portion 82 of the hammer 75 .

[0147] In this embodiment, the hammer bearing 30 is disposed so as to cover the front end of the screw hole 94. During the assembly of the impact tool 1, the screw 93 is turned with a screw tightening tool to adjust the compression amount of the elastic member 78, and then the hammer bearing 30 is disposed around the front outer cylindrical portion 82.

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

[0149] The tool holder shaft 31 is an output part of the impact tool 1 that rotates based on the rotational force of the rotor 36. At least a portion of the tool holder shaft 31 is disposed forward of the spindle 26. The tool holder shaft 31 has a tool holder portion 97 and an anvil portion 98 that is disposed rearward of the tool holder portion 97. The tool holder portion 97 is rod-shaped and extends in the front-rear direction. The anvil portion 98 is connected to the rear of the tool holder portion 97.

[0150] The tool holder 97 holds a tool bit. The tool holder 97 has a tool hole 99 into which the tool bit is inserted. The tool hole 99 is formed to extend rearward from the front end face of the tool holder 97. The tool bit is attached to the tool holder shaft 31.

[0151] The anvil portion 98 is disposed rearward of the tool holding portion 97. The anvil portion 98 is connected to the rear portion of the tool holding portion 97. The anvil portion 98 is disposed to surround the rotation axis AX. The anvil portion 98 has a recess 100 into which the front end portion of the spindle shaft portion 64 is inserted. The front end portion of the spindle shaft portion 64, including the spindle protrusion portion 69, is disposed inside the recess 100. The recess 100 is formed so as to recess forward from the rear end surface of the anvil portion 98. The recess 100 is defined by an inner circumferential surface 101 of the anvil portion 98 and an opposing surface 102 that is connected to the front end portion of the inner circumferential surface 101 of the anvil portion 98. The opposing surface 102 is a flat surface that faces rearward.

[0152] The anvil portion 98 has an anvil hole 104 that penetrates the outer peripheral surface 103 and the inner peripheral 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 on 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 disposed in the support recess 105. The support ball 106 contacts the opposing surface 102.

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

[0155] A suppressing member 108 that prevents the shaft bearing 32 from slipping out rearward is disposed behind the shaft bearing 32. The suppressing member 108 is disposed in a groove 109 formed in the inner circumferential surface of the small cylindrical portion 54. The suppressing member 108 is exemplified by a snap ring or a C-ring. The suppressing member 108 is disposed so as to contact the rear end surface of the shaft bearing 32. The suppressing member 108 prevents the shaft bearing 32 from slipping out rearward from the small cylindrical portion 54.

[0156] (movable anvil) The movable anvil 33 is movably supported on the tool holder shaft 31. In this embodiment, the movable anvil 33 moves only in the radial direction relative to the tool holder shaft 31. The movable anvil 33 does not move in the axial or radial directions relative to the tool holder shaft 31.

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

[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. The spindle protrusion 69 is positioned at the front end of the spindle shaft portion 64. When the spindle protrusion 69 comes into contact with the movable anvil 33, the movable anvil 33 moves radially outward. When the spindle protrusion 69 moves away from the movable anvil 33, the movable anvil 33 moves radially inward.

[0159] The movable anvil 33 moves so as 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 103 of the anvil portion 98 of the tool holder 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 holder shaft 31. As the spindle 26 rotates, the spindle protrusion 69 comes into contact with the movable anvil 33, causing the movable anvil 33 to change from the second state to the first state. In other words, when the spindle protrusion 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 protrusion 84 of the hammer 75 can come into contact with the movable anvil 33. The hammer 75 strikes the movable anvil 33 when the movable anvil 33 is in the first state. When the movable anvil 33 is in the second state, the hammer protrusion 84 of the hammer 75 cannot come into contact with 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 disposed around the tool holding portion 97, forward of the hammer case 23. The tool holding mechanism 34 holds a tool bit inserted into a tool hole 99 of the tool holding portion 97. The tool holding mechanism 34 is capable of attaching and detaching a tool bit.

[0162] The tool holding mechanism 34 includes 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 holding 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 balls 110 are movably supported by the tool holding portion 97. The retaining balls 110 are arranged in the support recesses 115. One retaining ball 110 is arranged 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 by the support recess 115, it is positioned inside the tool hole 99 via at least a portion of the retaining ball 110. The retaining ball 110 can fix a tool bit inserted into the tool hole 99. The retaining ball 110 is movable between an engagement position where the tool bit is fixed and a release position where the fixation of the tool bit is released.

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

[0167] The sleeve 112 is a cylindrical member. The sleeve 112 is disposed around the tool holding portion 97. The sleeve 112 is movable in the axial direction around the tool holding portion 97. The sleeve 112 can prevent the retaining ball 110, which is disposed in the engagement position, from escaping from the engagement position. By moving the sleeve 112 in the axial direction, the retaining ball 110 can be changed to a state in which it can be moved from the engagement position to the release position.

[0168] The sleeve 112 is movable around the tool holding portion 97 between a blocking position where the retaining ball 110 is prevented from moving radially outward and a permitting position where the retaining ball 110 is permitted to move radially outward.

[0169] By placing the sleeve 112 in the blocking position, the retaining ball 110, which is in the engagement position, is prevented from moving radially outward. In other words, by placing the sleeve 112 in the blocking position, the retaining ball 110, which is in the engagement position, is prevented from escaping from the engagement position. By placing the sleeve 112 in the blocking position, the bit 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 at the engagement position, is allowed to move radially outward. When the sleeve 112 is moved to the allowable position, the retaining ball 110 is changed to a state in which it can move from the engagement position to the release position. In other words, when the sleeve 112 is placed at the allowable position, the retaining ball 110, which is positioned at the engagement position, is allowed to move out of the engagement position. When the sleeve 112 is placed at the allowable position, the state in which the tool bit is fixed by the retaining ball 110 can be released.

[0171] The coil spring 113 generates an elastic force that moves the sleeve 112 to the blocking position. The coil spring 113 is disposed around the tool holding portion 97. The blocking position is set rearward of the allowable position. The coil spring 113 generates an elastic force that moves the sleeve 112 rearward.

[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 at a position where it can face the rear end of the sleeve 112. The positioning member 114 positions the sleeve 112 at the blocking position. The sleeve 112, which is given an elastic force moving rearward by the coil spring 113, comes into contact with the positioning member 114, and is positioned at the blocking position.

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

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

[0175] When performing a screw tightening operation on a workpiece, the tool bit (driver bit) to be used for the screw tightening operation is inserted into the tool hole 99 of the tool holding shaft 31. The tool bit inserted into the tool hole 99 is held by the tool holding mechanism 34. After the tool bit is attached to the tool holding shaft 31, the operator grips the grip portion 18 with, for example, the right hand and pulls the trigger lever 9 with the index finger of the right hand. When the trigger lever 9 is pulled, power is supplied from the battery pack 20 to the motor 6, the motor 6 is started, and a light is turned on. When the motor 6 is started, the rotor shaft 42 of the rotor 36 rotates. When 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 revolves around the pinion gear 48 while rotating on its axis 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. The revolution of the planetary gear 58 causes the spindle 26 to rotate at a rotational speed lower than the rotational speed of the rotor shaft 42.

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

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

[0178] 23, in a low load state, the spindle protrusion 69 comes into contact with the movable anvil 33, and the movable anvil 33 comes into contact with the hammer protrusion 84. In addition, the spindle protrusion 69 comes into contact with the movable anvil 33, and the movable anvil 33 comes into contact with the hammer protrusion 84.

[0179] In a low load state, the movable anvil 33 moves radially outward due to contact with the spindle protrusion 69. At least a portion of the movable anvil 33 is disposed radially outward from the outer circumferential surface of the anvil portion 98. Because at least a portion of the movable anvil 33 is disposed radially outward from the outer circumferential surface of the anvil portion 98, in a low load state the hammer protrusion 84 comes into contact with at least a portion of the movable anvil 33.

[0180] Under low load conditions, the wedge effect of the movable anvil 33 prevents the movable anvil 33 from passing between the spindle protrusion 69 and the hammer protrusion 84, preventing relative rotation among the spindle 26, hammer 75, and tool holder shaft 31. The tool holder shaft 31 rotates together with the hammer 75 and 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 an elastic member 78. Therefore, in a low-load state 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 a low-load state, the spindle 26, the hammer 75, the tool holder shaft 31, and the cam ring 76 rotate together.

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

[0183] 25 and 26 each show a cross-sectional view of the output assembly 4 in a transition state immediately after the load applied to the tool holding shaft 31 has transitioned from a low load state to a high load state.

[0184] As the screw tightening operation progresses, the load on the tool holder shaft 31 increases, causing the rotational speed of the tool holder shaft 31 to decrease. Because the hammer 75 is connected to the tool holder shaft 31 via the movable anvil 33, the rotational speed of the hammer 75 also decreases as the rotational speed of the tool holder shaft 31 decreases. Furthermore, because 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 also decreases as the rotational speed of the hammer 75 decreases. On the other hand, because the spindle 26 rotates due to the rotational force of the motor 6, the rotational speed of the spindle 26 does not decrease.

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

[0186] As shown in FIG. 25, when the load state transitions from a low load state to a high load state, the spindle protrusion 69 moves away from the movable anvil 33 due to the relative rotation of the tool holding shaft 31 and the hammer 75 with respect to the spindle 26 .

[0187] Because 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 also decreases as the rotational speed of the hammer 75 decreases. Since the rotational speed of the spindle 26 does not decrease, if the spindle 26 continues to rotate with the rotational speed of the cam ring 76 decreasing, the balls 77 move inside the spindle groove 71 and the cam groove 88.

[0188] As shown in Figure 26, when the load state transitions from a low load state to a high load state, balls 77 move in second portion 712 from the center of spindle groove 71 toward the end. Cam ring 76 receives force from balls 77 and moves forward. Cam ring 76 moves forward while being guided by guide groove 86. Cam ring 76 moves forward against the elastic force of elastic member 78.

[0189] In this way, 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, 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, the ball 77 moves through the second part 712 from the center of the spindle groove 71 toward the other circumferential end of the second part 712, and the cam ring 76 receives force from the ball 77 and moves forward.

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

[0191] Continuing the high load state stops the rotation of the tool holder shaft 31, hammer 75, and cam ring 76. Even after the rotation of the tool holder 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 holder shaft 31 is under a high load, the spindle 26 continues to rotate while the rotation of the tool holder shaft 31, hammer 75, and cam ring 76 is stopped. The cam ring 76 receives a force from the ball 77 and moves forward against the elastic force of the elastic member 78.

[0193] 27 , as the spindle 26 continues to rotate with the rotation of the tool holder shaft 31, the hammer 75, and the cam ring 76 stopped, the spindle protrusion 69 moves further away from the movable anvil 33 in the rotational direction. As the spindle protrusion 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 protrusion 84 moves away from the movable anvil 33. In other words, the hammer 75 is unlocked by the movable anvil 33, and the hammer 75 becomes rotatable relative to the spindle 26.

[0194] When the hammer 75 is unlocked, the cam ring 76 also becomes rotatable relative to the spindle 26. The cam ring 76 moves rearward relative to the hammer 75 due to the elastic force of the elastic member 78. The cam ring 76 moves rearward while being guided by the guide groove 86. Because the cam ring 76 is rotatable relative to the spindle 26, as it moves rearward, it receives force from the balls 77 and rotates in the forward direction. That is, the cam ring 76 rotates in the forward direction while moving rearward. The balls 77 move in the second portion 712 from the end of the spindle groove 71 toward the center. The hammer 75 is connected to the cam ring 76 via the cam slide portion 87 and the guide groove 86, and therefore, when the cam ring 76 rotates in the forward direction, the hammer 75 also rotates in the forward direction.

[0195] In this way, after the hammer 75 is unlocked, when the cam ring 76 receives an elastic force from the elastic member 78 to move rearward, the ball 77 moves along the second part 712 from the other circumferential end of the second part 712 toward the center of the spindle groove 71, and the cam ring 76 receives a force from the ball 77 and moves rearward while rotating relative to the flange part 65.

[0196] 29 and 30 each show a cross-sectional view of the output assembly 4 in a hammer rotation state in which the hammer 75 is rotating to strike the movable anvil 33. FIG.

[0197] 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 protrusion 691, which is separated from the first movable anvil 331, approaches the second movable anvil 332, and the second spindle protrusion 692, which is separated from the second movable anvil 332, approaches the first movable anvil 331. Furthermore, the hammer 75 rotates such that the first hammer protrusion 841, which is separated from the first movable anvil 331, approaches the second movable anvil 332, and the second hammer protrusion 842, which is separated from the second movable anvil 332, approaches the first movable anvil 331.

[0198] The first hammer protrusion 841 revolves around the spindle 26 in the normal direction so as to follow the first spindle protrusion 691. The first spindle protrusion 691 reaches the second movable anvil 332 before the first hammer protrusion 841. The second hammer protrusion 842 revolves around the spindle 26 in the normal direction so as to follow the second spindle protrusion 692. The second spindle protrusion 692 reaches the first movable anvil 331 before the second hammer protrusion 842.

[0199] 31 and 32 each show a cross-sectional view of the output assembly 4 in a striking state in which the hammer 75 strikes the movable anvil 33. FIG.

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

[0201] The first hammer protrusion 841 reaches the second movable anvil 332 after the first spindle protrusion 691 reaches the second movable anvil 332. That is, the first hammer protrusion 841 reaches the second movable anvil 332 after the second movable anvil 332 moves radially outward. The first hammer protrusion 841 strikes the second movable anvil 332, which is disposed 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 protrusion 841, the position of the second movable anvil 332 in the radial direction is constrained by the first spindle protrusion 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 protrusion 841 to strike the second movable anvil 332.

[0202] The second spindle protrusion 692 reaches the first movable anvil 331 before the second hammer protrusion 842. The first movable anvil 331 moves radially outward due to contact with the second spindle protrusion 692. The second hammer protrusion 842 reaches the first movable anvil 331 after the first movable anvil 331 moves radially outward. The second hammer protrusion 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 protrusion 842, the radial position of the first movable anvil 331 is constrained by the second spindle protrusion 692, and the circumferential position of the first movable anvil 331 is constrained by the inner surface of the anvil hole 104. This allows the second hammer protrusion 842 to strike the first movable anvil 331.

[0203] The striking of the second movable anvil 332 by the first hammer protrusion 841 and the striking of the first movable anvil 331 by the second hammer protrusion 842 are carried out substantially simultaneously. The movable anvil 33 is struck by the hammer protrusion 84 while being disposed in the anvil hole 104 of the tool holder shaft 31. The tool holder 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, and therefore rotates about the rotation axis AX with a high torque, so that the screw is tightened into the workpiece with a high torque.

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

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

[0207] As described with reference to FIGS. 23 to 32 , in this embodiment, the movable anvil 33 is struck by the hammer protrusion 84 when the spindle 26 makes a half rotation. That is, in this embodiment, the hammer protrusion 84 strikes the movable anvil 33 twice during one rotation of the spindle 26. The hammer protrusion 84 may strike the movable anvil 33 once during one rotation of the spindle 26. When the hammer protrusion 84 strikes the movable anvil 33 once during one rotation of the spindle 26, the hammer protrusion 84 can strike the movable anvil 33 at a higher rotational speed and with a higher inertial force than when the hammer protrusion 84 strikes the movable anvil 33 twice. That is, when the hammer protrusion 84 strikes the movable anvil 33 once during one rotation of the spindle 26, the hammer 75 can strike the movable anvil 33 with a higher impact energy than when the hammer protrusion 84 strikes the movable anvil 33 twice. By adjusting one or both of the elastic energy (spring constant) of the elastic member 78 and the rotational speed of the spindle 26, it is possible to adjust the number of times that the hammer protrusion 84 strikes the movable anvil 33 during one rotation of the spindle 26. As a secondary effect, the ease with which the elastic member 78 deforms accelerates the timing at which the hammer protrusion 84 starts striking the movable anvil 33, thereby suppressing the occurrence of the cam-out phenomenon in which the tip of the tool bit comes off the tool hole (cross hole) of the screw during screw tightening work.

[0208] In this embodiment, two movable anvils 33 and two hammer protrusions 84 are provided. Three movable anvils 33 and three hammer protrusions 84 may be provided. Four movable anvils 33 and four hammer protrusions 84 may be provided. Five or more movable anvils 33 and five or more hammer protrusions 84 may be provided.

[0209] 23 to 32 are examples in which the spindle 26, cam ring 76, hammer 75, and tool holder shaft 31 rotate in the forward direction for a screw tightening operation. When performing a screw loosening operation, the operator operates forward / reverse rotation switch lever 10 to rotate the spindle 26, cam ring 76, hammer 75, and tool holder shaft 31 in the reverse direction. During the screw loosening operation, when the flange portion 65 of the spindle 26 and the cam ring 76 are rotating together in the reverse direction, the tool holder shaft 31 is placed under a high load, the rotational speed of the cam ring 76 decreases, and the flange portion 65 and the cam ring 76 start to rotate relative to each other. As a result, the ball 77 moves in the first portion 711 from the center of the spindle groove 71 toward one circumferential end of the first portion 711, and the cam ring 76 receives a force from the ball 77 and moves forward. Furthermore, after the hammer 75 is unlocked, when the cam ring 76 receives an elastic force from the elastic member 78 so as to move rearward, the ball 77 moves along the first part 711 from one circumferential end of the first part 711 toward the center of the spindle groove 71, and the cam ring 76 receives a force from the ball 77 and moves rearward while rotating the flange part 65 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 at least a portion of which is arranged forward of the spindle 26, a hammer 75 supported by the spindle shaft portion 64 and which strikes the tool holding shaft 31 in the rotational direction, an elastic member 78 arranged axially between the front surface of the flange portion 65 and a support surface 90 of the hammer 75 which is arranged forward of the flange portion 65, and an elastic force adjustment mechanism 29 which adjusts the elastic force of the elastic member 78 in the initial state before the motor 6 is started.

[0211] In the above configuration, the elastic force of the elastic member 78 is adjustable, allowing the impact tool 1 to smoothly perform both high-load work and low-load work. When low-load work is being performed, the elastic force of the elastic member 78 is adjusted to be low, and when high-load work is being performed, the elastic force of the elastic member 78 is adjusted to be high, allowing the impact tool 1 to smoothly perform both high-load work and low-load work.

[0212] In this embodiment, the elastic force adjustment mechanism 29 may adjust the compression amount 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 compression amount of the elastic member 78 in the initial state. When the compression amount is small, the elastic force of the elastic member 78 is low, and when the compression amount is large, the elastic force of the elastic member 78 is 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 compression amount by moving the position of the front end of the elastic member 78.

[0215] In the above configuration, the position of the rear end of the elastic member 78 is fixed, and the position of the front end of the elastic member 78 is moved, thereby adjusting the compression amount.

[0216] In this embodiment, the elastic force adjustment mechanism 29 may have a screw 93 that is disposed in a threaded hole 94 formed in the hammer 75 and is 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, when the screw 93 is rotated while placed in the screw hole 94, the screw 93 moves in the front-rear direction, 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 contact 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, a plurality of screw holes 94 may be formed at intervals around the rotation axis of the hammer 75. One screw 93 may be disposed in each of the plurality of screw holes 94.

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

[0222] In the present 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 through a front end surface 95 of the rear outer cylinder portion 81 and the support surface 90.

[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 placed in the screw hole 94, and can smoothly rotate the screw 93.

[0224] In the present embodiment, the impact tool 1 may include a hammer case 23 that houses the 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 disposed around the front outer cylindrical portion 82.

[0225] In the above configuration, after adjustment of the elastic force by the screw 93 is completed, the hammer bearing 30 is positioned so as to cover the front end of the screw hole 94. In this way, the screw 93 is protected by the hammer bearing 30.

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

[0227] The above configuration prevents the impact tool 1 from becoming larger. When a predetermined elastic force is required for the elastic member 78, using the disc spring 91 allows the axial dimension of the elastic member 78 to be shorter than when, for example, a coil spring is used. This allows the hammer 75 to strike the tool holder shaft 31 in the rotational direction while preventing the impact tool 1 from becoming larger. 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 disposed at the rear end of the motor housing 17, and an output assembly 4 disposed in 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 the washer 79 .

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

[0231] In the above configuration, the movable anvil 33 is provided so as to be movably supported on the tool holding shaft 31, and therefore the hammer 75 can strike the movable anvil 33 in the rotational direction without being displaced in the axial direction. Because the hammer 75 does not displace in the axial direction, the generation of axial vibrations in the impact tool 1 is suppressed.

[0232] In this embodiment, the movable anvil 33 may be moved 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 holder shaft 31, and a second state in which the movable anvil 33 is positioned radially inward from the outer circumferential surface of the tool holder 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 the present embodiment, the impact tool 1 may include a cam ring 76 that is connected to the flange portion 65 via balls 77 so as to be relatively rotatable, and is connected to the hammer 75 so as to be relatively movable in the axial direction but not relatively rotatable. The cam ring 76 may be disposed so as to face the front surface of the flange portion 65. The elastic member 78 may be disposed between the front surface of the cam ring 76 and the support surface of the hammer 75 in the axial direction.

[0235] In the above configuration, the cam ring 76 is connected to the flange portion 65 of the spindle 26 via the balls 77 so as to be relatively rotatable. The cam ring 76 is also connected to the hammer 75 so as to be relatively movable in the axial direction but not rotatable relative to the hammer 75. This allows the hammer 75 to strike the tool holder shaft 31 in the rotational direction with its axial length 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 disposed in a closed 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 holder 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 holder 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 holder shaft 31. As a result, the tool holder shaft 31 is struck with a high striking force.

[0238] [Second embodiment] A second embodiment will be described below. 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 description of those components will be simplified or omitted.

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

[0240] The output assembly 4B has a hammer case 123 and a bearing box 24. A hammer 175 is disposed 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 cylinder portion 153 and a small cylinder portion 154. The large cylinder portion 153 and the small cylinder portion 154 are each arranged to surround the rotation axis AX. The small cylinder portion 154 is arranged forward of the large cylinder portion 153. The inner diameter of the large cylinder portion 153 is larger than the inner diameter of the small cylinder portion 154. The outer diameter of the large cylinder portion 153 is larger than the outer diameter of the small cylinder portion 154.

[0242] In this embodiment, the hammer case 123 has a through hole 116. The hammer case 123 has a front surface 155 facing forward and a rear surface 196 facing rearward. The front surface 155 is provided to connect the front end of the outer circumferential surface of the large cylinder portion 153 and the rear end of the outer circumferential surface of the small cylinder portion 154. The rear surface 196 is provided to connect the front end of the inner circumferential surface of the large cylinder portion 153 and the rear end of the inner circumferential surface of the small cylinder portion 154. Each of the front surface 155 and the rear surface 196 is annular. The through hole 116 is formed to penetrate the front surface 155 and the rear surface 196. A plurality of 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 above-described embodiment, the output assembly 4B includes a screw 93 as the elastic force adjustment mechanism 29. The hammer 175 includes a screw hole 94 in which the screw 93 is disposed. 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 rotational direction, the positions of the screw holes 94 and the positions of the through holes 116 coincide with each other 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 rotational 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 forward and backward. By moving the washer 79 in the front-rear direction, the compression amount 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 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 integral with each other.

[0245] The front outer cylinder portion 182 is disposed forward of the rear outer cylinder portion 181. The front end portion of the rear outer cylinder portion 181 is connected to the rear end portion 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 disposed radially inward of the rear outer cylinder portion 181 and the front outer cylinder portion 182. The front end portion of the inner cylinder portion 183 is connected to the rear end portion 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 disposed radially outward and forward of the inner cylinder portion 183. The rear outer cylinder portion 181 is disposed radially outward of the inner cylinder portion 183 and the front outer cylinder portion 82, and is disposed 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 located rearward of the front small diameter portion 181A. The rear small diameter portion 181C is located rearward of 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. The first hammer bearing 130A and the second hammer bearing 130B are each disposed around the rear outer cylinder portion 181. The second hammer bearing 130B is disposed rearward of the first hammer bearing 130A. The first hammer bearing 130A and the second hammer bearing 130B are each a ball bearing.

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

[0251] The first hammer bearing 130A is disposed around the front small diameter portion 181A. The inner ring of the first hammer bearing 130A contacts the outer peripheral surface of the front small diameter portion 181A. The outer ring of the first hammer bearing 130A contacts the inner peripheral 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 disposed radially outward of the rear surface 196. The support surface 197 is disposed rearward of 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 disposed around the rear small diameter portion 181C. The inner ring of the second hammer bearing 130B contacts the outer peripheral surface of the rear small diameter portion 181C. The outer ring of the second hammer bearing 130B contacts the inner peripheral 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 so as to recess forward from the rear end of the rear small diameter portion 181C. The multiple notches 181D allow the rear small diameter portion 181C to elastically deform 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 together. That is, 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 disposed around the rear small diameter portion 181C so as to fasten the rear small diameter portion 181C from the radially outer 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 the first hammer bearing 130A and the second hammer bearing 130B. The second hammer bearing 130B may be disposed rearward of the first hammer bearing 130A.

[0254] In the above configuration, the hammer 175 is prevented from rotating in an inclined state relative to the spindle 26.

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

[0256] In the above configuration, the hammer 175 is prevented from rotating in an inclined state relative to the spindle 26.

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

[0258] In the above configuration, the hammer 175 is prevented from rotating in an inclined state relative to the spindle 26.

[0259] In this embodiment, the rear outer cylinder portion 181 may have a front small diameter portion 181A, a large diameter portion 181B arranged rearward of the front small diameter portion 181A, and a rear small diameter portion 181C arranged 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 arranged around the front small diameter portion 181A. The second hammer bearing 130B may be arranged around the rear small diameter portion 181C.

[0260] In the above configuration, the hammer case 23 is prevented from becoming large in size in the radial direction.

[0261] In this embodiment, the hammer 175 may have a support surface 197 that faces the front end of the first hammer bearing 130 A. The front end of the first hammer bearing 130 A may contact 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 portion of the first hammer bearing 130A may come into contact with at least a part 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 portion of the second hammer bearing 130B may come into contact with at least a part 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 allow 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 together.

[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 a hammer 175. The hammer case 123 may have a through hole 116 that overlaps with the screw hole 94 in both the radial and circumferential directions. The screw 93 may be rotated through the through hole 116.

[0270] With the above configuration, the worker can smoothly bring the screw tightening tool into contact with the screw 93 placed in the screw hole 94 via the through hole 116, and can smoothly rotate the screw 93. The worker can appropriately adjust the elastic force of the elastic member 78 depending on the type of work.

[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 disposed around the rear outer cylindrical 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 the worker can smoothly bring the screw tightening tool into contact with the screw 93 placed in the screw hole 94 via the through hole 116, allowing the screw 93 to rotate smoothly.

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

[0274] <Impact tool> FIG. 37 is a front perspective view showing a portion of the impact tool 1C according to this embodiment. FIG. 38 is a longitudinal cross-sectional view showing a portion of the impact tool 1C according to this embodiment. FIG. 39 is a transverse cross-sectional view showing a portion of the impact tool 1C according to this embodiment. FIG. 40 is a cross-sectional view showing a portion of the impact tool 1C according to this embodiment, which corresponds to the cross-sectional view taken along line XX in FIG. 38. FIG. 41 is a cross-sectional view showing a portion of the impact tool 1C according to this embodiment, which corresponds to the cross-sectional view taken along line WW in FIG. 38. FIG. 42 is a cross-sectional view showing a portion of the impact tool 1C according to this embodiment, which corresponds to the cross-sectional view taken along line TT in FIG. 38. FIG. 43 is a cross-sectional view showing a portion of the impact tool 1C according to this embodiment, which corresponds to the cross-sectional view taken along line SS in FIG. 38. FIG. 44 is a cross-sectional view showing a portion of the impact tool 1C according to this embodiment, which corresponds to an enlarged view of a portion of FIG. 43. FIG. 45 is a top view of a portion of the impact tool 1C according to this embodiment.

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

[0276] The output assembly 4C has a hammer case 223, a bearing box 224, and a cover 119. The hammer 75 and the spindle 26 are disposed 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 relative to the bearing box 224. A screw groove 120 is formed in the rear part of the inner circumferential surface of the hammer case 223. A screw thread 121 is formed on the outer circumferential surface of the bearing box 224. The screw groove 120 and the screw thread 121 are coupled together. As the hammer case 223 rotates relative to the bearing box 224, the hammer case 223 moves in the front-to-rear direction relative to the bearing box 224.

[0278] The cover 119 is disposed so as to cover the hammer case 223. The worker can rotate the hammer case 223 while holding the cover 119. By rotating the hammer case 223 via the cover 119, the worker can move the hammer case 223 in the front-to-rear direction relative to the bearing box 224.

[0279] 41 , the output assembly 4C has a first anti-rotation mechanism 228 that suppresses relative rotation between the motor accommodating portion 217 and the bearing box 224. In the present embodiment, the first anti-rotation mechanism 228 includes a protrusion 222 that protrudes radially outward from the outer circumferential surface of the bearing box 224, and a recess 225 that is provided on the inner circumferential surface of the motor accommodating portion 217. The protrusion 222 is disposed in the recess 225, thereby suppressing relative rotation between the motor accommodating portion 217 and the bearing box 224.

[0280] 42, the output assembly 4C has a second anti-rotation mechanism 229 that suppresses relative rotation between the cover 119 and the hammer case 223. In this embodiment, the second anti-rotation mechanism 229 includes a protrusion 124 that protrudes radially outward from the outer circumferential surface of the hammer case 223, and a recess 125 that is provided on the inner circumferential surface of the cover 119. The protrusion 124 is disposed in the recess 125, thereby suppressing relative rotation between the cover 119 and the hammer case 223.

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

[0282] 43 and 44, the output assembly 4C has a positioning mechanism 231 that positions the cover 119 in the circumferential direction. The positioning mechanism 231 includes a plurality of recesses 126 provided in 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 in the circumferential direction relative to the housing 202.

[0283] The leaf spring 122 has a protrusion 127. The protrusion 127 is disposed in the recess 126. By disposing the protrusion 127 in the recess 126, the cover 119 is positioned in the circumferential direction.

[0284] As shown in Figures 37 and 45, a position mark 117 is provided on the outer peripheral surface of the cover 119. One position mark 117 is provided on the outer peripheral surface of the cover 119. The position mark 117 indicates the position of the cover 119 in the rotational direction. An index mark 118 is provided on the outer peripheral surface of the motor accommodating portion 217. A plurality of index marks 118 are provided in the circumferential direction. In the circumferential direction, the spacing between the plurality of recesses 126 and the spacing between the index marks 118 match. The index marks 118 indicate the amount of compression of the elastic member 78.

[0285] When the worker rotates the hammer case 223 via the cover 119 and the hammer case 223 moves in the front-to-rear direction, the hammer 75, which is connected to the hammer case 223 via the hammer bearing 30, moves in the front-to-rear direction together with the hammer case 223. 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, when the hammer 75 moves in the front-to-rear direction due to the rotation of the hammer case 223, the compression amount of the elastic member 78 changes. When the hammer case 223 is rotated so that the hammer 75 moves rearward, the distance between the cam ring 76 and the hammer 75 in the front-to-rear direction becomes shorter, and the elastic member 78 is compressed. When 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] By disposing the protrusions 127 in the recesses 126, the cover 119 is positioned in the circumferential direction, thereby suppressing unnecessary rotation of the cover 119. Furthermore, the leaf springs 122 provide the operator with a clicking sensation when the cover 119 is rotated. The operator rotates the cover 119 so that any one of the index marks 118 aligns with the position mark 117. Because the spacing between the multiple recesses 126 and the spacing between the index marks 118 match, when the cover 119 is rotated so that any one of the index marks 118 aligns with the position mark 117, the protrusions 127 are disposed in any one of the recesses 126, and the compression amount of the elastic member 78 is adjusted.

[0287] <Effects> As described above, in this embodiment, the impact tool 1C may include the bearing box 224 that holds the spindle 26, and the hammer case 223 that holds the hammer 75. The hammer case 223 may be coupled to the bearing box 224 via a threaded portion including the screw groove 120 and the 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 in the axial direction.

[0288] In the above configuration, the worker can adjust the elastic force of the elastic member 78 by manually gripping and rotating the hammer case 223. The worker 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 portion 217 that houses the motor 6, and a first anti-rotation mechanism 228 that prevents the motor housing portion 217 and the bearing box 224 from rotating relative to each other.

[0290] In the above configuration, when the hammer case 223 is rotated, the first anti-rotation mechanism 228 prevents the bearing box 224 from rotating, so 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 be rotated via the cover 119.

[0292] In the above configuration, the second anti-rotation mechanism 229 prevents relative rotation between the cover 119 and the hammer case 223, so an operator can rotate the hammer case 223 by grasping and rotating the cover 119 with their hands. By rotating the hammer case 223, the elastic force of the elastic member 78 is adjusted. 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 that positions the cover 119 in the circumferential direction.

[0294] In the above configuration, the hammer case 223 and the cover 119 are prevented from rotating unnecessarily.

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

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

[0297] The output assembly 4D has a hammer case 23 and a bearing box 24. A hammer 375 and an elastic member 378 are disposed 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 shown by imaginary lines.

[0298] As in the above-described embodiment, the elastic member 378 is disposed 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. Although there is no particular upper limit to the spring constant of the elastic member 378, 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 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 integral with each other.

[0300] The front outer cylinder portion 382 is disposed forward of the rear outer cylinder portion 381. The front end portion of the rear outer cylinder portion 381 is connected to the rear end portion 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 disposed radially inward of the rear outer cylinder portion 381 and the front outer cylinder portion 382. The front end portion of the inner cylinder portion 383 is connected to the rear end portion of the front outer cylinder portion 382.

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

[0303] The support pin 128 is disposed 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 disposing 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 holder 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 disposed inside the cylindrical portion 333A. The front end portion of the pin portion 333B protrudes forward from the front end surface of the cylindrical portion 333A. The rear end portion 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 contact 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 disposed 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-described embodiment, the impact tool is an impact driver. However, the impact tool may be an impact wrench.

[0312] In the above-described embodiment, the power source for the impact tool does not have to be the battery pack 20, and may be a commercial power source (AC power source). [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 switching lever, 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 holding 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 bearing, 47...rotor bearing, 48...pinion gear, 49...bush, 50...circuit board, 51...case, 52...operation button, 53...large cylinder portion, 54...small cylinder portion, 55...ring portion, 56...rear plate portion, 57...projection portion, 58...planetary gear, 59...pin, 60...internal gear, 61...O-ring, 62...projection portion, 63...recessed portion, 64...spindle shaft portion, 65...flange portion, 66...pin support portion, 67...connecting portion, 68...projection portion, 69...spindle protrusion portion, 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 cylindrical portion, 82...front outer cylindrical portion, 83...inner cylindrical portion, 84...hammer protrusion portion, 85...ball groove, 86...guide groove, 87...cam slide portion, 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 portion, 98...anvil portion, 99...tool hole, 100...recess, 101...inner peripheral surface, 102...opposing surface, 103...outer peripheral 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...index mark, 119...cover, 120...thread groove, 121...thread, 122...leaf spring, 123...hammer case, 12 4...protrusion, 125...recess, 126...recess, 127...protrusion, 128...support pin, 130A...first hammer bearing, 130B...second hammer bearing, 153...large cylinder portion, 154...small cylinder portion, 155...front surface, 175...hammer, 181...rear outer cylinder portion, 181A...front small diameter portion, 181B...large diameter portion, 181C...rear small diameter portion, 181D...notch, 182...front outer cylinder portion, 183...inner cylinder portion, 1 96... rear surface, 197... support surface, 202... housing, 217... motor accommodating portion, 222... convex portion, 223... hammer case, 224... bearing box, 225... concave portion, 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 portion, 333B... pin portion, 3 75...Hammer, 378...Elastic member, 381...Rear outer cylinder portion, 382...Front outer cylinder portion, 383...Inner cylinder portion, 385...Recessed portion, 390...Support surface, 391...Coil spring, 691...First spindle protrusion portion, 692...Second spindle protrusion portion, 841...First hammer protrusion portion, 842...Second hammer protrusion portion, 711...First portion, 712...Second portion, 881...Third portion, 882...Fourth portion, AX...Rotating axis.

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 rotational force 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 striking 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 adjusting mechanism that adjusts the elastic force of the elastic member in an initial state before the motor is started; a cam ring that is connected to the flange portion via a ball so as to be relatively rotatable, and is connected to the hammer so as to be relatively movable in the axial direction but not rotatable relative to the hammer, and faces a front surface of the flange portion, The hammer has a recess formed so as to recess forward from a rear surface of the hammer, a washer disposed inside the recess and supporting a front end of the elastic member; The rear end of the elastic member contacts the front surface of the cam ring. Impact tool.

2. the elastic force adjustment mechanism adjusts the compression amount of the elastic member in the initial state. The impact tool according to claim 1 .

3. 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 rotational force 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 striking 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 adjusting mechanism that adjusts the elastic force of the elastic member in an initial state before the motor is started, The rear end of the elastic member is supported by the flange portion, the elastic force adjustment mechanism adjusts the compression amount of the elastic member in the initial state by moving the position of a front end of the elastic member; the elastic force adjustment mechanism has a screw disposed in a screw hole formed in the hammer and connected to a front end of the elastic member; The amount of compression is adjusted by rotating the screw. Impact tool.

4. 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. The impact tool according to claim 3.

5. The screw holes are formed at intervals around the rotation axis of the hammer, The screws are disposed one by one in each of the plurality of screw holes. The impact tool according to claim 3.

6. the hammer has an inner cylindrical portion disposed around the spindle shaft portion, a front outer cylindrical portion disposed radially outward and forward of the inner cylindrical portion, and a rear outer cylindrical portion disposed radially outward of the front outer cylindrical portion and rearward of the front outer cylindrical portion, the screw hole is formed to penetrate through the front end surface of the rear outer cylindrical portion and the support surface. The impact tool according to claim 3.

7. a hammer case that houses the hammer; a hammer bearing that is held in the hammer case and rotatably supports the hammer; The hammer bearing is disposed around the front outer cylinder portion.

7. The impact tool according to claim 6.

8. a hammer case for accommodating the hammer; the hammer case has through holes that overlap with the screw holes in both the radial and circumferential directions, The screw is rotated through the through hole.

7. The impact tool according to claim 6.

9. a hammer bearing that is held in the hammer case and rotatably supports the hammer; The hammer bearing is disposed around the rear outer cylindrical portion.

9. The impact tool according to claim 8.

10. 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 rotational force 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 striking 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 adjusting mechanism that adjusts the elastic force of the elastic member in an initial state before the motor is started; 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 threaded 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. Impact tool.

11. 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, 11. An impact tool according to claim 10.

12. a cover that covers 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.

11. An impact tool according to claim 10.

13. a positioning mechanism for positioning the cover in the circumferential direction; 13. An impact tool according to claim 12.

14. The elastic member includes a disc spring. The impact tool according to claim 1 .

15. 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.

15. An impact tool according to claim 14.

16. 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 rotational force 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 striking 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 adjusting mechanism that adjusts the elastic force of the elastic member in an initial state before the motor is started; 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. Impact tool.

17. 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 the outer circumferential surface of the tool holder shaft and a second state in which the movable anvil is positioned 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.

17. An impact tool according to claim 16.

18. 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 to the hammer; the cam ring is disposed so as to face the 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.

17. An impact tool according to claim 16.

19. 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.

19. An impact tool according to claim 18.

Images