Impact tools

Abstract

To suppress deterioration in workability using an impact tool.SOLUTION: An impact tool includes a motor, a spindle which is arranged ahead of the motor and is rotated by the motor, an inner hammer supported by the spindle, an outer hammer which is arranged in a periphery of the inner hammer and is rotated together with the inner hammer, an anvil struck in a rotation direction by the inner hammer, a hammer case storing the inner hammer and the outer hammer, and a bearing which is held by the hammer case and rotatably supports the outer hammer.SELECTED DRAWING: Figure 7

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, a rotary 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. 2019-195893 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to improve the workability when using an impact tool, a technique is required to prevent the impact tool from becoming larger.

[0005] The technology disclosed in this specification aims to prevent the impact tool from becoming larger in size. [Means for solving the problem]

[0006] This specification discloses an impact tool. The impact tool may include a motor, a spindle disposed forward of the motor and rotated by the motor, an inner hammer supported by the spindle, an outer hammer disposed around the inner hammer and rotating together with the inner hammer, an anvil struck in the rotational direction by the inner hammer, a hammer case that houses the inner hammer and the outer hammer, and a bearing held in the hammer case that rotatably supports the outer hammer. [Effects of the Invention]

[0007] According to the technology disclosed in this specification, the impact tool is prevented from becoming large. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front perspective view showing a power tool according to a first embodiment. [Figure 2] FIG. 2 is a perspective view of the power tool according to the first embodiment, seen from behind. [Figure 3] FIG. 3 is a side view showing the power tool according to the first embodiment. [Figure 4] FIG. 4 is a vertical cross-sectional view showing the power tool according to the first embodiment. [Figure 5] FIG. 5 is a side view showing the main body assembly according to the first embodiment. [Figure 6] FIG. 6 is a front view showing the main body assembly according to the first embodiment. [Figure 7] FIG. 7 is a vertical cross-sectional view showing the main body assembly according to the first embodiment, and corresponds to a cross-sectional view taken along line LL in FIG. [Figure 8] FIG. 8 is a cross-sectional view showing the main body assembly according to the first embodiment, and corresponds to a cross-sectional view taken along line TT in FIG. [Figure 9] FIG. 9 is a cross-sectional view showing the main body assembly according to the first embodiment, and corresponds to a cross-sectional view taken along line AA in FIG. [Figure 10] FIG. 10 is a cross-sectional view showing the main body assembly according to the first embodiment, and corresponds to a cross-sectional view taken along the line BB in FIG. [Figure 11] FIG. 11 is a cross-sectional view showing the main body assembly according to the first embodiment, and corresponds to a cross-sectional view taken along the line CC in FIG. [Figure 12] FIG. 12 is a cross-sectional view showing the main body assembly according to the first embodiment, and corresponds to a cross-sectional view taken along the line DD in FIG. [Figure 13] FIG. 13 is a cross-sectional view showing the main body assembly according to the first embodiment, and corresponds to a cross-sectional view taken along the line EE in FIG. [Figure 14] FIG. 14 is a cross-sectional view showing the main body assembly according to the first embodiment, and corresponds to a cross-sectional view taken along line GG in FIG. [Figure 15] FIG. 15 is a cross-sectional view showing the main body assembly according to the first embodiment, and corresponds to a cross-sectional view taken along the line FF in FIG. [Figure 16] FIG. 16 is an exploded perspective view showing the main body assembly according to the first embodiment. [Figure 17] FIG. 17 is a diagram for explaining the operation of the tool holding mechanism according to the first embodiment. [Figure 18] FIG. 18 is a vertical cross-sectional view showing a main body assembly according to the second embodiment. [Figure 19] FIG. 19 is a cross-sectional view showing a main body assembly according to the second embodiment. [Figure 20] FIG. 20 is an exploded perspective view showing a main body assembly according to the second embodiment. [Figure 21] FIG. 21 is a vertical cross-sectional view showing a main body assembly according to the third embodiment. [Figure 22] FIG. 22 is a cross-sectional view showing a main body assembly according to the third embodiment. [Figure 23] FIG. 23 is an exploded perspective view showing a main body assembly according to the third embodiment. [Figure 24] FIG. 24 is a longitudinal sectional view showing a main body assembly according to the fourth embodiment. [Figure 25] FIG. 25 is a cross-sectional view showing a main body assembly according to the fourth embodiment. [Figure 26] FIG. 26 is a longitudinal sectional view showing a main body assembly according to the fifth embodiment. [Figure 27] FIG. 27 is a cross-sectional view showing a main body assembly according to the fifth embodiment. [Figure 28] FIG. 28 is a longitudinal sectional view showing a main body assembly according to the sixth embodiment. [Figure 29] FIG. 29 is a cross-sectional view showing a main body assembly according to the sixth embodiment. [Figure 30] FIG. 30 is a longitudinal sectional view showing a main body assembly according to the seventh embodiment. [Figure 31]FIG. 31 is a cross-sectional view showing a main body assembly according to the seventh embodiment. [Figure 32] FIG. 32 is a front perspective view showing the main body assembly according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] In one or more embodiments, the impact tool may include a motor, a spindle disposed forward of the motor and rotated by the motor, an inner hammer supported by the spindle, an outer hammer disposed around the inner hammer and rotating together with the inner hammer, an anvil struck in the rotational direction by the inner hammer, a hammer case that houses the inner hammer and the outer hammer, and a bearing held in the hammer case that rotatably supports the outer hammer.

[0010] In the above configuration, in an impact tool having an inner hammer and an outer hammer, the outer hammer is rotatably supported by a bearing held in the hammer case, thereby preventing the impact tool from becoming large. 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 a main body assembly disposed at the front end 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 main body assembly.

[0011] In one or more embodiments, the impact tool may include a connecting member that connects the inner hammer and the outer hammer. The inner hammer may move axially relative to the outer hammer while being guided by the outer hammer via the connecting member.

[0012] In the above configuration, the inner hammer is movable in the axial direction, so that the inner hammer rotates while moving forward, and can strike the anvil in the rotational direction. Because the outer hammer does not move axially relative to the hammer case, the generation of axial vibrations in the impact tool is suppressed.

[0013] In one or more embodiments, the spindle may have a spindle shaft portion and a flange portion provided at a rear portion of the spindle shaft portion. The impact tool may include a coil spring disposed around the spindle shaft portion and generating a resilient force that moves the inner hammer forward. The rear end of the coil spring may be supported by the flange portion.

[0014] In the above configuration, the rear end of the coil spring is supported by the flange portion of the spindle, thereby shortening the axial length of the impact tool.

[0015] In one or more embodiments, the spindle and the outer hammer may be separate.

[0016] In the above configuration, the outer hammer is connected to the inner hammer via a connecting member, but is not directly connected to the spindle, which reduces the number of parts in the impact tool and prevents the impact tool from becoming too large.

[0017] In one or more embodiments, the outer hammer is cylindrical, and the outer surface of the outer hammer may include a large outer diameter surface and a small outer diameter surface that is arranged rearward of the large outer diameter surface and is connected to the large outer diameter surface via a stepped surface. The outer diameter of the outer hammer at the large outer diameter surface may be larger than the outer diameter of the outer hammer at the small outer diameter surface. The bearing may be arranged around the small outer diameter surface.

[0018] In the above configuration, the bearing is disposed around the small outer diameter surface, which prevents the impact tool from becoming too large.

[0019] In one or more embodiments, the hammer case has a cylindrical portion, and the inner surface of the cylindrical portion may include a small inner diameter surface and a large inner diameter surface that is arranged rearward of the small inner diameter surface and is connected to the small inner diameter surface via a stepped surface. The inner diameter of the cylindrical portion at the small inner diameter surface may be smaller than the inner diameter of the cylindrical portion at the large inner diameter surface. The front end surface of the bearing may contact each of the stepped surface of the outer hammer and the stepped surface of the hammer case. The impact tool may include a gear case fixed to the rear end of the hammer case and in contact with the rear end surface of the bearing.

[0020] In the above configuration, the front end surface of the bearing contacts the stepped surface of the outer hammer and the stepped surface of the hammer case, and the rear end surface of the bearing contacts the gear case, thereby positioning the bearing.

[0021] 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.

[0022] 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 power tool 1. In the embodiment, the power tool 1 is a rotary tool having an output shaft that rotates around a rotation axis AX.

[0023] In the embodiments, the direction parallel to the rotation axis AX is referred to as the axial direction, the direction circumferentially around the rotation axis AX is referred to as the circumferential direction or rotational direction, and the radial direction of the rotation axis AX is referred to as the radial direction.

[0024] A direction or position away from the center of the power tool 1 in a specified direction in the axial direction will be referred to as "one axial side," and the opposite side of the one axial side will be referred to as "the other axial side." A specified direction in the circumferential direction will be referred to as "one circumferential side," and the opposite side of the one circumferential side will be referred to as "the other circumferential side." A direction or position away from the rotation axis AX in the radial direction will be referred to as "the radially outer side," and the opposite side of the radially outer side will be referred to as "the radially inner side."

[0025] 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.

[0026] In the embodiment, the power tool 1 is an impact tool. Examples of the impact tool include an impact driver and an impact wrench.

[0027] [First embodiment] A first embodiment will be described below. In this embodiment, the power tool 1 is an impact driver.

[0028] <Outline of power tools> Fig. 1 is a front perspective view of the power tool 1 according to this embodiment. Fig. 2 is a rear perspective view of the power tool 1 according to this embodiment. Fig. 3 is a side view of the power tool 1 according to this embodiment. Fig. 4 is a vertical cross-sectional view of the power tool 1 according to this embodiment.

[0029] The power tool 1 includes a housing 2, a rear cover 3, a main body assembly 4A, a battery mounting portion 5, a motor 6, a fan 7, a controller 8, a trigger switch 9, and a forward / reverse rotation switch lever 10.

[0030] The housing 2 accommodates at least some of the components of the power 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 split housing halves. The housing 2 includes a left housing 2L and a right housing 2R located to the right of the left housing 2L. The left housing 2L and the right housing 2R are fixed together by a plurality of screws 2S.

[0031] The housing 2 has a motor accommodating portion 2A, a grip portion 2B, and a battery holding portion 2C.

[0032] The motor accommodating portion 2A accommodates the motor 6. The motor accommodating portion 2A is cylindrical.

[0033] The grip portion 2B is held by an operator and protrudes downward from the motor housing portion 2A. The trigger switch 9 is provided on the upper portion of the grip portion 2B.

[0034] The battery holding portion 2C holds the battery pack 20 via the battery attachment portion 5. The battery holding portion 2C houses the controller 8. The battery holding portion 2C is connected to the lower end of the grip portion 2B. The external dimensions of the battery holding portion 2C are larger than the external dimensions of the grip portion 2B in both the front-rear and left-right directions.

[0035] The rear cover 3 covers the opening at the rear end of the motor housing portion 2A. The rear cover 3 is positioned rearward of the motor housing portion 2A. The rear cover 3 is made of synthetic resin. The rear cover 3 is fixed to the rear end of the motor housing portion 2A with two screws 3S. The rear cover 3 houses the fan 7.

[0036] The motor accommodating section 2A has an intake port 7A. The rear cover 3 has an exhaust port 7B. Air from the external space of the housing 2 flows into the internal space of the housing 2 through the intake port 7A. Air from the internal space of the housing 2 flows out to the external space of the housing 2 through the exhaust port 7B.

[0037] The main body assembly 4A is disposed forward of the motor 6. The main body assembly 4A has a hammer case 11, a gear case 12, a front cover 13, a reduction mechanism 14, a spindle 15, a striking mechanism 16, an anvil 17, and a tool holding mechanism 18.

[0038] The hammer case 11 is made of metal. In this embodiment, the hammer case 11 is made of aluminum. At least a portion of the hammer case 11 is arranged forward of the motor accommodating section 2A. The hammer case 11 is cylindrical. The gear case 12 is fixed to the rear end of the hammer case 11. The front cover 13 is fixed to the front end of the hammer case 11 with three screws 19. The rear parts of the gear case 12 and the hammer case 11 are arranged inside the motor accommodating section 2A. The rear parts of the gear case 12 and the hammer case 11 are sandwiched between the left housing 2L and the right housing 2R. The gear case 12 and the hammer case 11 are each fixed to the motor accommodating section 2A.

[0039] At least a portion of the reduction mechanism 14, spindle 15, striking mechanism 16, anvil 17, and tool holding mechanism 18 are disposed in the internal space of the main body assembly 4A defined by the hammer case 11, gear case 12, and front cover 13.

[0040] The battery attachment section 5 has a battery pack 20 attached thereto. The battery attachment section 5 is disposed below the battery holding section 2C. The battery pack 20 is detachable from the battery attachment section 5. 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 2C. 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 power tool 1. The motor 6 is driven based on the power supplied from the battery pack 20. The controller 8 operates based on the power supplied from the battery pack 20.

[0041] The motor 6 is a power source of the power tool 1. The motor 6 is an electric motor. The motor 6 is an inner rotor type brushless motor. The motor 6 has a stator 21 and a rotor 22. At least a portion of the rotor 22 is disposed inside the stator 21. The rotor 22 rotates relative to the stator 21.

[0042] The stator 21 includes a stator core 21A, a rear insulator 21B, a front insulator 21C, and a coil 21D.

[0043] The stator core 21A is fixed to the motor accommodating portion 2A. The stator core 21A is sandwiched between the left housing 2L and the right housing 2R. The stator core 21A is disposed radially outward of the rotor 22. The stator core 21A includes a plurality of stacked steel plates. The steel plates are metal plates whose main component is iron. The stator core 21A is cylindrical. The stator core 21A has a plurality of teeth that support the coils 21D.

[0044] The rear insulator 21B is provided at the rear of the stator core 21A. The front insulator 21C is provided at the front of the stator core 21A. The rear insulator 21B and the front insulator 21C are each an electrical insulating member made of synthetic resin. The rear insulator 21B is arranged to cover part of the surface of the teeth. The front insulator 21C is arranged to cover part of the surface of the teeth.

[0045] The coil 21D is attached to the stator core 21A via the rear insulator 21B and the front insulator 21C. A plurality of coils 21D are arranged. The coils 21D are arranged around the teeth of the stator core 21A via the rear insulator 21B and the front insulator 21C. The coils 21D and the stator core 21A are electrically insulated by the rear insulator 21B and the front insulator 21C. The plurality of coils 21D are connected via crossover wires 21E. The coils 21D are connected to the controller 8 via lead wires (not shown).

[0046] The rotor 22 has a rotor core portion 22A, a rotor shaft portion 22B, a rotor magnet 22C, and a sensor magnet 22D.

[0047] The rotor core portion 22A and the rotor shaft portion 22B are each made of steel. The rotor shaft portion 22B protrudes in the front-rear direction from an end face of the rotor core portion 22A.

[0048] The rotor magnet 22C is fixed to the rotor core portion 22A. The rotor magnet 22C has a cylindrical shape. The rotor magnet 22C is arranged around the rotor core portion 22A.

[0049] The sensor magnet 22D is fixed to the rotor core portion 22A. The sensor magnet 22D has an annular shape. The sensor magnet 22D is disposed on the front end surface of the rotor core portion 22A and the front end surface of the rotor magnet 22C.

[0050] A sensor board 23 is attached to the front insulator 21C. The sensor board 23 is fixed to the front insulator 21C with screws 23S. The sensor board 23 has an annular circuit board and a rotation detection element supported by the circuit board. At least a portion of the sensor board 23 faces the sensor magnet 22D. The rotation detection element detects the position of the sensor magnet 22D, thereby detecting the position of the rotor 22 in the rotational direction.

[0051] The rear end of rotor shaft portion 22B is rotatably supported by rotor bearing 24. The front end of rotor shaft portion 22B is rotatably supported by rotor bearing 25. Rotor bearing 24 is held by rear cover 3. Rotor bearing 25 is held by bearing holder 26. Bearing holder 26 is held by gear case 12. The front end of rotor shaft portion 22B is disposed in the internal space of main body assembly 4A through the opening of bearing holder 26.

[0052] A pinion gear 27 is fixed to the front end of the rotor shaft portion 22B. The pinion gear 27 is connected to at least a part of the reduction mechanism 14. The rotor shaft portion 22B is connected to the reduction mechanism 14 via the pinion gear 27.

[0053] 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 24 and the stator 21. The fan 7 is fixed to at least a portion of the rotor 22. The fan 7 is fixed to the rear of the rotor shaft portion 22B via a bushing 7C. The fan 7 rotates with the rotation of the rotor 22. As the rotor shaft portion 22B rotates, the fan 7 rotates together with the rotor shaft portion 22B. 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 intake port 7A. 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 exhaust port 7B.

[0054] The controller 8 outputs a control signal to control the motor 6. The controller 8 is housed in the battery holding section 2C. The controller 8 switches the control mode of the motor 6 based on the type of work being performed by the power tool 1. The control mode of the motor 6 refers to a control method or control pattern for the motor 6. The controller 8 includes a circuit board 8A on which multiple electronic components are mounted, and a case 8B that houses the circuit board 8A. Examples of electronic components mounted on the circuit board 8A 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.

[0055] The trigger switch 9 is operated by an operator to start the motor 6. The trigger switch 9 is provided on the grip portion 2B. The trigger switch 9 includes a trigger lever 9A and a switch body 9B. The trigger lever 9A protrudes forward from the upper front portion of the grip portion 2B. The trigger lever 9A is operated by an operator. The switch body 9B is housed in the grip portion 2B. Operating the trigger lever 9A switches between driving and stopping the motor 6.

[0056] 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 2B. 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 15 is switched.

[0057] <Main body assembly> FIG. 5 is a side view showing a main body assembly 4A according to this embodiment. FIG. 6 is a front view showing a main body assembly 4A according to this embodiment. FIG. 7 is a longitudinal cross-sectional view showing a main body assembly 4A according to this embodiment, corresponding to the cross-sectional view taken along line LL in FIG. 6. FIG. 8 is a transverse cross-sectional view showing a main body assembly 4A according to this embodiment, corresponding to the cross-sectional view taken along line TT in FIG. 6. FIG. 9 is a cross-sectional view showing a main body assembly 4A according to this embodiment, corresponding to the cross-sectional view taken along line AA in FIG. 7. FIG. 10 is a cross-sectional view showing a main body assembly 4A according to this embodiment, corresponding to the cross-sectional view taken along line BB in FIG. 7. FIG. 11 is a cross-sectional view showing a main body assembly 4A according to this embodiment, corresponding to the cross-sectional view taken along line CC in FIG. 7. FIG. 12 is a cross-sectional view showing a main body assembly 4A according to this embodiment, corresponding to the cross-sectional view taken along line DD in FIG. 7. FIG. 13 is a cross-sectional view showing a main body assembly 4A according to this embodiment, corresponding to the cross-sectional view taken along line EE in FIG. 7. FIG. 14 is a cross-sectional view showing a main body assembly 4A according to this embodiment, corresponding to the cross-sectional view taken along line GG in FIG. 7. Fig. 15 is a cross-sectional view showing a main body assembly 4A according to this embodiment, and corresponds to a cross-sectional view taken along the line FF in Fig. 6. Fig. 16 is an exploded perspective view showing a main body assembly 4A according to this embodiment.

[0058] The main body assembly 4A has a hammer case 11, a gear case 12, a front cover 13, a reduction mechanism 14, a spindle 15, an impact mechanism 16, an anvil 17, a tool holding mechanism 18, a spindle bearing 28, a hammer bearing 29, an anvil bearing 30, a bearing holder 26, and a bearing holder 31.

[0059] The rotor 22, spindle 15, and anvil 17 each rotate about a rotation axis AX. The rotation axis of the rotor 22, the rotation axis of the spindle 15, and the rotation axis of the anvil 17 are aligned. The spindle 15 and the anvil 17 are each rotated by a rotational force generated by the motor 6.

[0060] (Hammer case) The hammer case 11 has a tubular portion 11S, a front plate portion 11T, and a boss portion 11H. The tubular portion 11S is arranged to surround the rotation axis AX. The front plate portion 11T is connected to the front end of the tubular portion 11S. An opening is provided in the center of the front plate portion 11T. The boss portion 11H is provided on the front surface of the front plate portion 11T. The boss portion 11H protrudes forward from the front surface of the front plate portion 11T. The boss portion 11H is arranged to surround the opening of the front plate portion 11T.

[0061] The outer surface of the tubular portion 11S of the hammer case 11 includes a small outer diameter surface 11A, a stepped surface 11B, and a large outer diameter surface 11C. The large outer diameter surface 11C is located rearward of the small outer diameter surface 11A. The stepped surface 11B faces forward. The large outer diameter surface 11C is connected to the small outer diameter surface 11A via the stepped surface 11B. The outer diameter of the tubular portion 11S at the small outer diameter surface 11A is smaller than the outer diameter of the tubular portion 11S at the large outer diameter surface 11C.

[0062] The inner surface of the motor accommodating section 2A is connected to the large outer diameter surface 11C, the step surface 11B, and a portion of the small outer diameter surface 11A. A protrusion 11G is provided on a portion of the small outer diameter surface 11A. The protrusion 11G protrudes radially outward from the small outer diameter surface 11A. The protrusion 11G is disposed in a recess provided on the inner surface of the motor accommodating section 2A. By disposing the protrusion 11G in the recess of the motor accommodating section 2A, relative rotation between the motor accommodating section 2A and the hammer case 11 is suppressed.

[0063] The inner surface of the tubular portion 11S of the hammer case 11 includes a small inner diameter surface 11D, a stepped surface 11E, and a large inner diameter surface 11F. The large inner diameter surface 11F is located rearward of the small inner diameter surface 11D. The stepped surface 11E faces rearward. The large inner diameter surface 11F is connected to the small inner diameter surface 11D via the stepped surface 11E. The inner diameter of the tubular portion 11S at the small inner diameter surface 11D is smaller than the inner diameter of the tubular portion 11S at the large inner diameter surface 11F.

[0064] The gear case 12 is fixed to the rear end of the hammer case 11. The gear case 12 has a ring portion 12A, a rear plate portion 12B, and a protrusion 12C. The ring portion 12A is arranged to surround the rotation axis AX. The rear plate portion 12B is connected to the rear end of the ring portion 12A. An O-ring 57 is arranged at the boundary between the peripheral edge of the rear plate portion 12B and the rear end of the hammer case 11. An opening is provided in the center of the rear plate portion 12B. The protrusion 12C is provided on the rear surface of the rear plate portion 12B. The protrusion 12C protrudes rearward from the rear surface of the rear plate portion 12B. The protrusion 12C is arranged to surround the opening of the rear plate portion 12B. The rear plate portion 12B and the protrusion 12C are each connected to the motor accommodating portion 2A.

[0065] A recess 12D is provided at the front end of the ring portion 12A. The recess 12D is formed so as to recess rearward from the front end of the ring portion 12A. A plurality of recesses 12D are provided at intervals in the circumferential direction.

[0066] The front cover 13 is fixed to the front end of the hammer case 11 with three screws 19. An opening is provided in the center of the front cover 13. The front cover 13 has a through hole 13A into which the screw 19 is inserted. A screw hole 11J into which the screw 19 is inserted is provided in the boss portion 11H of the hammer case 11. The screw 19 inserted into the through hole 13A is then inserted into the screw hole 11J, and the thread of the screw 19 is engaged with the thread groove of the screw hole 11J, thereby fixing the front cover 13 to the front end of the hammer case 11.

[0067] The bearing holder 26 is fixed to the gear case 12. The bearing holder 26 is inserted into an opening provided in the center of the gear case 12. The bearing holder 26 holds the rotor bearing 25 and the spindle bearing 28. As shown in FIG. 4 , the rotor bearing 25 is disposed radially inside the bearing holder 26. The spindle bearing 28 is disposed radially outside the bearing holder 26.

[0068] The gear case 12 is made of synthetic resin. Because the gear case 12 is made of synthetic resin, the weight of the main body assembly 4A is reduced. The bearing holder 26 is made of metal such as iron. Because the bearing holder 26 is made of metal, a decrease in the rigidity of the main body assembly 4A is suppressed. Furthermore, the rotor bearing 25 and the spindle bearing 28 are each held in the highly rigid bearing holder 26.

[0069] (Deceleration mechanism) The reduction mechanism 14 connects the rotor shaft portion 22B and the spindle 15. The reduction mechanism 14 transmits the rotation of the rotor 22 to the spindle 15. The reduction mechanism 14 rotates the spindle 15 at a rotational speed lower than the rotational speed of the rotor shaft portion 22B. The reduction mechanism 14 includes a planetary gear mechanism.

[0070] The reduction mechanism 14 has a plurality of planetary gears 32 arranged around the pinion gear 27, pins 33 supporting each of the planetary gears 32, and an internal gear 34 arranged around the planetary gears 32. Each of the planetary gears 32 meshes with the pinion gear 27. The planetary gears 32 are rotatably supported on the spindle 15 via the pins 33. The spindle 15 is rotated by the planetary gears 32. The internal gear 34 has internal teeth that mesh with the planetary gears 32.

[0071] The internal gear 34 is fixed to both the hammer case 11 and the gear case 12. A protrusion 34A is provided on the outer surface of the internal gear 34. The protrusion 34A protrudes radially outward from the outer surface of the internal gear 34. A plurality of protrusions 34A are provided at intervals in the circumferential direction. The protrusions 34A are arranged in the recess 12D of the gear case 12. This suppresses relative rotation between the gear case 12 and the internal gear 34. The internal gear 34 is always unable to rotate relative to the hammer case 11.

[0072] With the protrusion 34A disposed in the recess 12D, the front end surface of the ring portion 12A is disposed forward of the front end surface of the internal gear 34.

[0073] When the rotor shaft portion 22B is rotated by the drive of the motor 6, the pinion gear 27 rotates, and the planetary gear 32 revolves around the pinion gear 27. The planetary gear 32 revolves while meshing with the internal teeth of the internal gear 34. Due to the revolution of the planetary gear 32, the spindle 15 connected to the planetary gear 32 via the pin 33 rotates at a rotational speed lower than the rotational speed of the rotor shaft portion 22B.

[0074] (Spindle) At least a portion of the spindle 15 is disposed forward of the reduction mechanism 14. The spindle 15 is rotated by the rotor 22 of the motor 6. The spindle 15 is rotated by the rotational force of the rotor 22 transmitted by the reduction mechanism 14. The spindle 15 transmits the rotational force of the motor 6 to the anvil 17 via the impact mechanism 16.

[0075] The spindle 15 has a spindle shaft portion 15A, a flange portion 15B, a pin support portion 15C, and a bearing retaining portion 15D. The spindle shaft portion 15A extends in the axial direction. The spindle shaft portion 15A is cylindrical. The spindle shaft portion 15A is arranged to surround the rotation axis AX. The flange portion 15B is provided at the rear portion of the spindle shaft portion 15A. The flange portion 15B protrudes radially outward from the rear portion of the spindle shaft portion 15A. The pin support portion 15C is arranged rearward of the flange portion 15B. The pin support portion 15C is annular. A portion of the flange portion 15B and a portion of the pin support portion 15C are connected via a connecting portion 15E. The bearing retaining portion 15D protrudes rearward from the pin support portion 15C.

[0076] The planetary gear 32 is disposed between the flange portion 15B and the pin support portion 15C. The front end of the pin 33 is disposed in a support hole 15F provided in the flange portion 15B. The rear end of the pin 33 is disposed in a support hole 15G provided in the pin support portion 15C. The planetary gear 32 is rotatably supported by both the flange portion 15B and the pin support portion 15C via the pin 33.

[0077] The bearing holder 15D is disposed around the spindle bearing 28. The spindle 15 is rotatably supported by the spindle bearing 28. A washer 60 is disposed at a position facing the front end of the outer ring of the spindle bearing 28.

[0078] (impact mechanism) The striking mechanism 16 is driven by the motor 6. The rotational force of the motor 6 is transmitted to the striking mechanism 16 via the reduction mechanism 14 and the spindle 15. The striking mechanism 16 strikes the anvil 17 in the rotational direction based on the rotational force of the spindle 15 rotated by the motor 6.

[0079] The striking mechanism 16 includes an inner hammer 35 , an outer hammer 36 , a connecting member 37 , a ball 38 , a coil spring 39 , a washer 40 , and a ball 41 .

[0080] The inner hammer 35 strikes the anvil 17 in the rotational direction. The inner hammer 35 is supported by the spindle 15. The inner hammer 35 is disposed around the spindle shaft portion 15A. The inner hammer 35 is disposed forward of the reduction mechanism 14.

[0081] The inner hammer 35 has a hammer main body 35A and a hammer protrusion 35B. The hammer main body 35A is cylindrical. The hammer main body 35A is arranged around the spindle shaft 15A. The hammer protrusion 35B is provided at the front of the hammer main body 35A. The hammer protrusion 35B protrudes forward from the front of the hammer main body 35A. Two hammer protrusions 35B are provided around the rotation axis AX. A ring-shaped recess 35C is provided on the rear surface of the hammer main body 35A. The recess 35C is formed so as to recess forward from the rear surface of the hammer main body 35A.

[0082] The outer hammer 36 is disposed around the inner hammer 35. The outer hammer 36 is cylindrical. The outer hammer 36 is disposed so as to surround the rotation axis AX. A washer 59 is disposed inside the hammer case 11 at a position facing the front end of the outer hammer 36.

[0083] The outer surface of the outer hammer 36 includes a large outer diameter surface 36A, a stepped surface 36B, and a small outer diameter surface 36C. The small outer diameter surface 36C is located rearward of the large outer diameter surface 36A. The stepped surface 36B faces rearward. The small outer diameter surface 36C is connected to the large outer diameter surface 36A via the stepped surface 36B. The outer diameter of the outer hammer 36 at the large outer diameter surface 36A is larger than the outer diameter of the outer hammer 36 at the small outer diameter surface 36C.

[0084] The connecting member 37 connects the inner hammer 35 and the outer hammer 36. The connecting member 37 includes a plurality of balls arranged between the inner hammer 35 and the outer hammer 36. A retaining groove 35D is provided on the outer surface of the hammer main body 35A. The retaining groove 35D is long in the axial direction. A plurality of retaining grooves 35D are provided at intervals in the circumferential direction. The connecting member 37 is arranged in the retaining groove 35D. Three connecting members 37 are arranged in the axial direction in one retaining groove 35D. A guide groove 36D that guides the connecting member 37 in the axial direction is provided on the inner surface of the outer hammer 36. The guide groove 36D is long in the axial direction. In the axial direction, the length of the guide groove 36D is longer than the length of the retaining groove 35D.

[0085] The inner hammer 35 and the outer hammer 36 are capable of relative movement in the axial direction. The inner hammer 35 moves in the axial direction relative to the outer hammer 36 while being guided by a guide groove 36D of the outer hammer 36 via a connecting member 37.

[0086] The ball 38 is disposed between the spindle 15 and the inner hammer 35. The ball 38 is disposed between the spindle shaft portion 15A and the hammer body portion 35A. The ball 38 is made of a metal such as steel. The spindle shaft portion 15A has a spindle groove 15H in which at least a portion of the ball 38 is disposed. The spindle groove 15H is provided on a portion of the outer surface of the spindle shaft portion 15A. The hammer body portion 35A has a hammer groove 35E in which at least a portion of the ball 38 is disposed. The hammer groove 35E is provided on a portion of the inner surface of the hammer body portion 35A. The ball 38 is disposed between the spindle groove 15H and the hammer groove 35E. The ball 38 can roll inside the spindle groove 15H and inside the hammer groove 35E. The inner hammer 35 is movable along with the ball 38. The spindle 15 and the inner hammer 35 can move relative to each other in the axial direction and the rotational direction within a movable range defined by the spindle groove 15H and the hammer groove 35E.

[0087] The inner hammer 35 is connected to the spindle 15 via a ball 38. The inner hammer 35 can rotate together with the spindle 15 based on the rotational force of the spindle 15 rotated by the motor 6. The inner hammer 35 rotates around the rotation axis AX. The spindle 15 and the outer hammer 36 are spaced apart. The outer hammer 36 is connected to the inner hammer 35 via a connecting member 37. The outer hammer 36 rotates together with the inner hammer 35. The outer hammer 36 rotates around the rotation axis AX.

[0088] The washer 40 is disposed inside the recess 35C. The ball 41 is disposed forward of the washer 40. A plurality of balls 41 are provided around the rotation axis AX. The washer 40 is supported by the inner hammer 35 via the plurality of balls 41.

[0089] The coil spring 39 is disposed around the spindle shaft portion 15A. The rear end of the coil spring 39 is supported by the flange portion 15B. The front end of the coil spring 39 is disposed inside the recess 35C. The front end of the coil spring 39 is supported by a washer 40. The coil spring 39 constantly generates an elastic force that moves the inner hammer 35 forward.

[0090] The hammer bearing 29 rotatably supports the outer hammer 36. The hammer bearing 29 is held by the hammer case 11. The hammer bearing 29 is disposed around the small outer diameter surface 36C of the outer hammer 36.

[0091] The front end surface of the hammer bearing 29 contacts the stepped surface 36B of the outer hammer 36 and the stepped surface 11E of the hammer case 11. As described above, with the convex portion 34A positioned in the concave portion 12D, the front end surface of the ring portion 12A is positioned forward of the front end surface of the internal gear 34. The front end surface of the ring portion 12A of the gear case 12 contacts the rear end surface of the hammer bearing 29. The hammer bearing 29 is sandwiched in the front-rear direction between the stepped surfaces 36B and 11E and the ring portion 12A. This positions the hammer bearing 29 in the axial direction. In addition, the outer surface of the hammer bearing 29 contacts the large inner diameter surface 11F of the hammer case 11. This positions the hammer bearing 29 in the radial direction. In addition, the contact between the outer surface of the hammer bearing 29 and the large inner diameter surface 11F of the hammer case 11 positions the outer ring of the hammer bearing 29 in the circumferential direction.

[0092] (Anvil) The anvil 17 is struck in the rotational direction by the inner hammer 35. The anvil 17 is disposed forward of the motor 6. The anvil 17 functions as an output shaft of the power tool 1 that is rotated based on the rotational force of the rotor 22. At least a portion of the anvil 17 is disposed forward of the spindle 15. At least a portion of the anvil 17 is disposed forward of the inner hammer 35. The anvil 17 has an insertion hole 42 into which a tool bit is inserted. The insertion hole 42 is formed to extend rearward from the front end of the anvil 17. The tool bit is attached to the anvil 17.

[0093] The anvil 17 has an anvil shaft portion 17A and an anvil protrusion portion 17B. The anvil shaft portion 17A extends in the axial direction. An insertion hole 42 is provided in the anvil shaft portion 17A. The insertion hole 42 is formed to extend rearward from the front end of the anvil shaft portion 17A. A tool bit is attached to the anvil shaft portion 17A. The anvil protrusion portion 17B is provided at the front portion of the anvil 17. The anvil protrusion portion 17B protrudes radially outward from the front portion of the anvil shaft portion 17A. The anvil protrusion portion 17B is struck in the rotational direction by the hammer protrusion portion 35B of the inner hammer 35.

[0094] The anvil shaft portion 17A includes a rear shaft portion 17Ar that is positioned rearward of the anvil protrusion 17B, and a front shaft portion 17Af that is positioned forward of the anvil protrusion 17B. In the axial direction, the length Lr of the rear shaft portion 17Ar is longer than the length Lf of the front shaft portion 17Af.

[0095] The anvil 17 is connected to the spindle 15. The spindle shaft portion 15A has a support hole 15J into which the anvil 17 is inserted. The support hole 15J is formed to extend rearward from the front end portion of the spindle shaft portion 15A. The rear shaft portion 17Ar of the anvil shaft portion 17A is inserted into the support hole 15J.

[0096] A groove 17K is provided on the outer peripheral surface of the rear shaft portion 17Ar. A space 54 filled with lubricating oil is formed between the groove 17K and the spindle shaft portion 15A. The lubricating oil includes grease. The lubricating oil is supplied between the inner surface of the spindle shaft portion 15A and the outer surface of the rear shaft portion 17Ar. O-rings 55 are disposed at the boundary between the inner surface of the spindle shaft portion 15A and the outer surface of the rear shaft portion 17Ar. The O-rings 55 are disposed at the front and rear of the space 54.

[0097] A rear end portion 17R of the anvil 17 is disposed rearward of the ball 38. A rear end portion of the insertion hole 42 is disposed rearward of the ball 38.

[0098] The anvil bearing 30 rotatably supports the anvil 17. The anvil bearing 30 rotatably supports the anvil shaft portion 17A. The anvil bearing 30 is disposed around the front shaft portion 17Af. The anvil bearing 30 rotatably supports the front shaft portion 17Af. An O-ring 58 is disposed at the boundary between the front shaft portion 17Af and the anvil bearing 30.

[0099] The front end 17F of the anvil 17 is located rearward of the front surface of the front cover 13. The front end 17F of the anvil 17 is located rearward of the front end surface of the anvil bearing 30. Note that the position of the front end 17F of the anvil 17 and the position of the front end surface of the anvil bearing 30 may coincide in the axial direction. The front end 17F of the anvil 17 may also be located forward of the front end surface of the anvil bearing 30.

[0100] The bearing holder 31 holds the anvil bearing 30. At least a portion of the bearing holder 31 is arranged to face the front surface of the anvil protrusion 17B. The bearing holder 31 contacts at least a portion of the anvil bearing 30. The bearing holder 31 is a ring member. The bearing holder 31 is arranged in an opening in the front plate portion 11T of the hammer case 11. The bearing holder 31 is fixed to the front end portion of the hammer case 11. The hammer case 11 holds the anvil bearing 30 via the bearing holder 31.

[0101] The bearing holder 31 includes a first portion 31A, a second portion 31B, and a third portion 31C. The first portion 31A is positioned rearward of the anvil bearing 30. The first portion 31A faces the rear end surface of the anvil bearing 30. The first portion 31A contacts the rear end surface of the anvil bearing 30. The second portion 31B extends forward from the outer edge of the first portion 31A. The second portion 31B is positioned radially outward from the outer surface of the anvil bearing 30, which faces radially outward. The second portion 31B faces the outer surface of the anvil bearing 30. The second portion 31B contacts the outer surface of the anvil bearing 30. The third portion 31C extends radially outward from the front end of the second portion 31B. The third portion 31C faces the front surface of the boss portion 11H. The third portion 31C contacts the front surface of the boss portion 11H.

[0102] The front surface of the anvil protrusion 17B includes a first surface 17G, a stepped surface 17H, and a second surface 17J. The second surface 17J is located rearward of the first surface 17G. The second surface 17J is located radially outward of the first surface 17G. The stepped surface 17H ​​faces radially outward. The second surface 17J is connected to the first surface 17G via the stepped surface 17H.

[0103] The first surface 17G contacts at least a portion of the bearing holder 31. The second surface 17J separates from the bearing holder 31. The first surface 17G contacts the rear surface of the first portion 31A of the bearing holder 31. The anvil 17 rotates with the first surface 17G in contact with the rear surface of the first portion 31A.

[0104] The rear surface of the anvil protrusion 17B is flat. In the axial direction, the distance D2 between the second surface 17J and the rear surface of the anvil protrusion 17B is smaller than the distance D1 between the first surface 17G and the rear surface of the anvil protrusion 17B. In other words, the thickness of the anvil protrusion 17B at the second surface 17J is thinner than the thickness of the anvil protrusion 17B at the first surface 17G.

[0105] The hammer protrusion 35B of the inner hammer 35 can come into contact with the anvil protrusion 17B of the anvil 17. When the motor 6 is driven while the hammer protrusion 35B and the anvil protrusion 17B are in contact with each other, the anvil 17 rotates together with the inner hammer 35 and the spindle 15.

[0106] The anvil 17 is struck in the rotational direction by the inner hammer 35. For example, during a screw tightening operation, if the load acting on the anvil 17 becomes too high, the anvil 17 may no longer be able to rotate with the load of the coil spring 39 alone. When the load of the coil spring 39 alone is no longer enough to rotate the anvil 17, the rotation of the anvil 17 and the inner hammer 35 stops. The spindle 15 and the inner hammer 35 are capable of relative movement in the axial and circumferential directions via the ball 38. Even after the rotation of the inner hammer 35 stops, the rotation of the spindle 15 continues due to the power generated by the motor 6. When the spindle 15 rotates while the rotation of the inner hammer 35 is stopped, the ball 38 moves rearward while being guided by the spindle groove 15H and the hammer groove 35E. The inner hammer 35 receives force from the ball 38 and moves rearward along with the ball 38. That is, the inner hammer 35 moves rearward by rotating the spindle 15 while the rotation of the anvil 17 is stopped. When the inner hammer 35 moves rearward, the contact between the inner hammer 35 and the anvil protrusion 17B is released.

[0107] As described above, the coil spring 39 constantly generates an elastic force that moves the inner hammer 35 forward. After moving rearward, the inner hammer 35 moves forward due to the elastic force of the coil spring 39. When the inner hammer 35 moves forward, it receives a rotational force from the ball 38. That is, the inner hammer 35 moves forward while rotating. When the inner hammer 35 moves forward while rotating, the inner hammer 35 comes into contact with the anvil protrusion 17B while rotating. As a result, the anvil protrusion 17B is struck in the rotational direction by the hammer protrusion 35B. Both the power of the motor 6 and the inertial force of the inner hammer 35 act on the anvil 17. Therefore, the anvil 17 can rotate around the rotation axis AX with high torque.

[0108] The outer hammer 36 rotates together with the inner hammer 35. When the inner hammer 35 strikes the anvil 17 in the rotational direction, the inertial force of the outer hammer 36 in the rotational direction acts on the anvil 17 together with the inertial force of the inner hammer 35 in the rotational direction. As a result, the anvil 17 is struck in the rotational direction with a high striking force.

[0109] Although the outer hammer 36 rotates together with the inner hammer 35, it does not move axially relative to the spindle 15 and the hammer case 11. In other words, even if the inner hammer 35 moves in the front-to-rear direction relative to the spindle 15, the outer hammer 36 does not move in the front-to-rear direction. Because the outer hammer 36 does not move in the front-to-rear direction, vibration of the main body assembly 4A in the front-to-rear direction is suppressed.

[0110] (Tool holding mechanism) 17 is a diagram for explaining the operation of the tool holding mechanism 18 according to this embodiment. The tool holding mechanism 18 holds the tool bit 61 inserted into the insertion hole 42 of the anvil 17. The tool holding mechanism 18 is detachable from the tool bit 61.

[0111] The tool holding mechanism 18 includes a locking member 43 , a bit sleeve 44 , an operating member 45 , a transmission mechanism 46 , a positioning member 47 , a sleeve spring 48 , and an elastic ring 49 .

[0112] The locking member 43 is supported by the anvil 17. The locking member 43 is supported by the anvil shaft portion 17A. The locking member 43 is supported by the rear shaft portion 17Ar.

[0113] The anvil 17 has a support recess 50 that supports the lock member 43. The support recess 50 is formed on the outer surface of the rear shaft portion 17Ar. In the embodiment, two support recesses 50 are formed in the anvil shaft portion 17A.

[0114] The locking member 43 is ball-shaped. The locking member 43 is disposed in the support recess 50. One locking member 43 is disposed in each support recess 50. The locking member 43 is housed in the hammer case 11. The locking member 43 is disposed rearward of the anvil bearing 30. The inner hammer 35 and the locking member 43 overlap in the axial direction. The outer hammer 36 and the locking member 43 overlap in the axial direction.

[0115] A through hole 51 connecting the inner surface of the support recess 50 and the inner surface of the insertion hole 42 is formed in the rear shaft portion 17Ar. The diameter of the locking member 43 is smaller than the diameter of the through hole 51. With the locking member 43 supported by the support recess 50, at least a portion of the locking member 43 is disposed inside the insertion hole 42 through the through hole 51. The locking member 43 can fix the tool bit inserted into the insertion hole 42. The tool bit 61 is locked by disposing at least a portion of the locking member 43 through the through hole 51 in a groove portion 61A provided on the side surface of the tool bit 61.

[0116] The locking member 43 is movable in the support recess 50. The locking member 43 is movable between a locked position where the locking member 43 locks the tool bit 61 inserted in the insertion hole 42 and an unlocked position where the locking member 43 unlocks the tool bit 61. The locked position includes a position where the locking member 43 is disposed inside the insertion hole 42 so that at least a portion of the locking member 43 is inserted into the groove 61A of the tool bit 61 through the through hole 51. The unlocked position includes a position where the locking member 43 is disposed outside the insertion hole 42 so that the locking member 43 is removed from the groove 61A of the tool bit 61. The locking member 43 is disposed at the locked position by moving radially inward in the support recess 50. The locking member 43 is disposed at the unlocked position by moving radially outward in the support recess 50.

[0117] The bit sleeve 44 is disposed around the anvil 17. The bit sleeve 44 is movable around the anvil 17 between a blocking position that blocks radially outward movement of the locking member 43 and an allowable position that allows radially outward movement of the locking member 43. The bit sleeve 44 is movable in the axial direction around the anvil 17. In this embodiment, the allowable position is defined forward of the blocking position. The bit sleeve 44 is disposed at the blocking position by moving rearward around the anvil 17. The bit sleeve 44 is disposed at the allowable position by moving forward around the anvil 17.

[0118] When the bit sleeve 44 is placed in the blocking position, the locking member 43, which is placed in the locked position, is prevented from moving radially outward. That is, when the bit sleeve 44 is placed in the blocking position, the locking member 43, which is placed in the locked position, is prevented from moving out of the locked position. When the bit sleeve 44 is placed in the blocking position, the bit tool is maintained in a state where it is fixed by the locking member 43.

[0119] When the bit sleeve 44 is moved to the allowable position, the locking member 43, which is in the locked position, is allowed to move radially outward. That is, when the bit sleeve 44 is moved to the allowable position, the locking member 43, which is in the locked position, is allowed to move out of the locked position and into the released position. When the bit sleeve 44 is placed in the allowable position, the state in which the tool bit is fixed by the locking member 43 can be released.

[0120] The bit sleeve 44 has a contact portion 44A, a tubular portion 44B, and an operating portion 44C. The contact portion 44A is arranged around the rear shaft portion 17Ar. The contact portion 44A is capable of contacting the locking member 43. The contact portion 44A is movable around the rear shaft portion 17Ar between a blocking position and an allowing position. The tubular portion 44B is connected to an outer edge portion on the radially outer side of the contact portion 44A. The tubular portion 44B is arranged to extend forward from the outer edge portion of the contact portion 44A. The operating portion 44C is connected to a front end portion of the tubular portion 44B. The operating portion 44C is arranged to extend radially outward from the front end portion of the tubular portion 44B.

[0121] At least a portion of the bit sleeve 44 is disposed radially between the inner hammer 35 and the anvil 17. At least a portion of the bit sleeve 44 is disposed radially between the inner hammer 35 and the rear shaft portion 17Ar. At least the contact portion 44A of the bit sleeve 44 is disposed radially between the hammer body portion 35A and the rear shaft portion 17Ar.

[0122] Furthermore, at least a portion of the bit sleeve 44 is disposed radially between the spindle shaft portion 15A and the anvil shaft portion 17A. In this embodiment, at least the contact portion 44A of the bit sleeve 44 is disposed inside the spindle shaft portion 15A. At least the contact portion 44A of the bit sleeve 44 is disposed radially between the inner surface of the spindle shaft portion 15A and the outer surface of the rear shaft portion 17Ar.

[0123] The bit sleeve 44 is housed in the hammer case 11. The bit sleeve is disposed rearward of the anvil bearing 30.

[0124] The operating member 45 is operated by an operator to move the bit sleeve 44. The operating member 45 is disposed outside the hammer case 11. The operating member 45 is supported by the hammer case 11. The operating member 45 is ring-shaped. At least a portion of the operating member 45 is disposed between the front surface of the hammer case 11 and the rear surface of the front cover 13. The operating member 45 is disposed around the boss portion 11H of the hammer case 11. The operating member 45 is rotatably supported by the boss portion 11H. The operating member 45 is operated by an operator to rotate in the circumferential direction. The front cover 13 prevents the operating member 45 from slipping forward from the boss portion 11H. When the operating member 45 is operated to rotate in the circumferential direction, the bit sleeve 44 moves in the axial direction. When the operating member 45 is operated to rotate in the circumferential direction, the bit sleeve 44 moves between the blocking position and the allowing position.

[0125] The transmission mechanism 46 transmits the force applied to the operating member 45 to the bit sleeve 44. The transmission mechanism 46 functions as a conversion mechanism that converts the rotation of the operating member 45 into the movement of the bit sleeve 44 in the axial direction.

[0126] The operating member 45 has a ring portion 45A, a cam portion 45B, a recessed portion 45C, and a protruding portion 45D. The ring portion 45A is disposed radially outward from the boss portion 11H and the front cover 13. The cam portion 45B is disposed radially inward from the ring portion 45A. The recessed portion 45C is provided on the inner surface of the ring portion 45A. As shown in FIG. 9 , a plurality of recessed portions 45C are provided at intervals in the circumferential direction. The protruding portion 45D is provided on the outer surface of the ring portion 45A. A plurality of protruding portions 45D are provided at intervals in the circumferential direction. An operator can rotate the operating member 45 while gripping at least a portion of the outer surface of the ring portion 45A and the surface of the protruding portion 45D. The plurality of protruding portions 45D prevents the operator's hand from slipping relative to the operating member 45.

[0127] In the axial direction, the anvil bearing 30 and at least a part of the operating member 45 overlap. In this embodiment, the position of at least the rear end of the operating member 45 and the position of at least a part of the anvil bearing 30 coincide with each other in the axial direction.

[0128] The transmission mechanism 46 has a pin 52 and a bit washer 53. The pin 52 is positioned rearward of the cam portion 45B. The pin 52 moves axially in contact with the cam portion 45B as the operating member 45 rotates. The cam portion 45B has a cam surface 45E. The cam surface 45E faces rearward. The cam surface 45E is inclined forward toward one circumferential side. The pin 52 moves axially in contact with the cam surface 45E as the operating member 45 rotates. The bit washer 53 is positioned rearward of the pin 52. It contacts both the pin 52 and the bit sleeve 44.

[0129] Three pins 52 are provided. An O-ring 56 is attached to the pin 52. A groove 52A is provided on the outer peripheral surface of the pin 52. The O-ring 56 is placed in the groove 52A. The pin 52 is placed in a guide hole 11K provided in the boss portion 11H. The pin 52 can move in the axial direction while being guided by the guide hole 11K. The pin 52 is guided by the hammer case 11 so as to move in the axial direction. The pin 52 is supported by the hammer case 11 so as not to move in the circumferential direction relative to the hammer case 11.

[0130] The bit washer 53 has a ring portion 53A, a protrusion 53B, and a protrusion 53C. The protrusion 53C protrudes radially outward from the ring portion 53A. The protrusion 53C protrudes radially outward and forward from the ring portion 53A. The rear end of the pin 52 contacts the protrusion 53B. The ring portion 53A contacts the operating portion 44C of the bit sleeve 44. When the pin 52 moves rearward, the bit washer 53 is pushed by the pin 52 and moves rearward. When the bit washer 53 moves rearward, the bit sleeve 44 is pushed by the bit washer 53 and moves rearward. The protrusion 53C is disposed in a recess 11L formed on the rear surface of the boss portion 11H. By disposing the protrusion 53C in the recess 11L, the bit washer 53 is supported by the hammer case 11 so as not to move circumferentially relative to the hammer case 11.

[0131] The positioning member 47 positions the operating member 45 in the circumferential direction. The positioning member 47 includes a leaf spring. As shown in FIG. 9 , the positioning member 47 is placed in a recess 11M provided in the boss portion 11H. The positioning member 47 is supported by the hammer case 11 so as not to move in the circumferential direction relative to the hammer case 11.

[0132] The positioning member 47 has a body portion 47A and a protrusion 47B. The body portion 47A is disposed in a recess 11M provided in the boss portion 11H. The protrusion 47B is disposed in a recess 45C provided on the inner surface of the ring portion 45A. By disposing the protrusion 47B in the recess 45C, the operating member 45 is positioned in the circumferential direction.

[0133] By rotating the operating member 45, the bit sleeve 44 moves in the axial direction between the blocking position and the allowing position. By positioning the operating member 45 at a first circumferential position by the positioning member 47, the bit sleeve 44 is positioned at the blocking position. By positioning the positioning member 47 at a second circumferential position, the bit sleeve 44 is positioned at the allowing position. In other words, by fixing the rotational position of the operating member 45 by the positioning member 47, the axial position of the bit sleeve 44, which is connected to the operating member 45 via the transmission mechanism 46, is fixed.

[0134] The sleeve spring 48 generates an elastic force so that the bit sleeve 44 moves to the permissible position. The sleeve spring 48 is a coil spring arranged around the anvil shaft portion 17A. The sleeve spring 48 is arranged rearward of the bit sleeve 44. The front end of the sleeve spring 48 contacts the rear end of the contact portion 44A. The rear end of the sleeve spring 48 contacts at least a portion of the spindle shaft portion 15A. The sleeve spring 48 generates an elastic force so that the bit sleeve 44 moves forward. As described above, in this embodiment, the permissible position is defined forward of the blocking position. The sleeve spring 48 generates an elastic force that moves the bit sleeve 44 forward, thereby moving the bit sleeve 44 to the permissible position.

[0135] The elastic ring 49 generates an elastic force that moves the locking member 43 to the locked position. The elastic ring 49 is disposed around the rear shaft portion 17Ar. The elastic ring 49 generates an elastic force that moves the locking member 43 forward and radially inward. An example of the elastic ring 49 is an O-ring.

[0136] <Tool holding mechanism operation> When moving the bit sleeve 44 from the permitting position to the blocking position, the operator operates the operating member 45 so that the operating member 45 rotates from the second circumferential position to the first position. When the operating member 45 is in the second circumferential position, the convex portion 47B of the positioning member 47 is positioned in a specific one of the multiple concave portions 45C of the operating member 45. When the operator rotates the operating member 45 from the second circumferential position to the first position, the positioning member 47 elastically deforms, and the convex portion 47B escapes from the concave portion 45C. This releases the positioning performed by the positioning member 47, allowing the operator to rotate the operating member 45.

[0137] When the operating member 45 is rotated from the second circumferential position to the first position, the pin 52 is pushed rearward by the cam surface 45E of the operating member 45. When the pin 52 is pushed rearward by the cam surface 45E, the bit sleeve 44 is pushed rearward by the pin 52 via the bit washer 53. That is, the bit sleeve 44 moves rearward. The bit sleeve 44 moves rearward against the elastic force of the sleeve spring 48. When the bit sleeve 44 moves rearward, the bit sleeve 44 is positioned at the blocking position. When the bit sleeve 44 is positioned at the blocking position and the operating member 45 is positioned at the first circumferential position, the convex portion 47B of the positioning member 47 is positioned at a specific one of the multiple concave portions 45C of the operating member 45. As a result, the operating member 45 is positioned at the first circumferential position, and the bit sleeve 44 is positioned at the blocking position.

[0138] When moving the bit sleeve 44 from the blocking position to the allowing position, the operator operates the operating member 45 so that the operating member 45 rotates from the first position to the second position in the circumferential direction. When the operator rotates the operating member 45 from the first position to the second position in the circumferential direction, the positioning member 47 elastically deforms, and the convex portion 47B escapes from the concave portion 45C. This releases the positioning by the positioning member 47, allowing the operator to rotate the operating member 45.

[0139] When the positioning by the positioning member 47 is released, the bit sleeve 44 is moved forward by the elastic force of the sleeve spring 48. When the operating member 45 is rotated from the first position to the second position in the circumferential direction, the bit sleeve 44 is moved to the allowable position by the elastic force of the sleeve spring 48. When the bit sleeve 44 is positioned at the allowable position and the operating member 45 is positioned at the second position in the circumferential direction, the convex portion 47B of the positioning member 47 is positioned in a specific one of the multiple concave portions 45C of the operating member 45. As a result, the operating member 45 is positioned at the second position in the circumferential direction, and the bit sleeve 44 is positioned at the allowable position.

[0140] When attaching the tip tool 61 to the anvil 17, the operator inserts the anvil 17 into the insertion hole 42 through an insertion opening provided at the front end of the insertion hole 42. In this embodiment, the operator can attach the tip tool 61 to the anvil 17 using either a one-touch method or a two-touch method.

[0141] The one-touch method refers to an attachment method in which the anvil 17 is attached to the tool bit 61 by inserting the tool bit 61 into the insertion hole 42 with the bit sleeve 44 in the blocking position. As shown in FIG. 17 , when the bit sleeve 44 is in the blocking position, the contact portion 44A is located radially outward of the locking member 43. That is, when the bit sleeve 44 is in the blocking position, the locking member 43 is located in a locked position where radially outward movement is prevented by the contact portion 44A. When the tool bit 61 is inserted into the insertion hole 42 with the bit sleeve 44 in the blocking position, the locking member 43 is pushed rearward by the tapered surface 61B provided at the rear end of the tool bit 61. When the locking member 43 is pushed rearward by the tool bit 61, the locking member 43 moves rearward from the contact portion 44A and separates from the contact portion 44A. That is, even though the bit sleeve 44 is in the blocking position, when the locking member 43 is pushed rearward by the tool accessory 61, the locking member 43 escapes from the locked position and moves to the unlocked position. An elastic ring 49 is disposed rearward of the contact portion 44A. When the locking member 43 is pushed rearward by the tool accessory 61, it moves from the locked position to the unlocked position where it contacts the elastic ring 49. The locking member 43 is pushed by the tapered surface 61B, so it moves rearward and radially outward from the contact portion 44A while in contact with the elastic ring 49. The movement of the locking member 43 elastically deforms the elastic ring 49 so that its diameter expands. Because the locking member 43 moves radially outward, the operator can insert the tool accessory 61 into the insertion hole 42. When the tool accessory 61 is inserted into the insertion hole 42 until the groove portion 61A of the tool accessory 61 faces the locking member 43 in the unlocked position, the elastic force of the elastic ring 49 causes the locking member 43 to move forward and radially inward. The elastic force of the elastic ring 49 causes the locking member 43 to move forward and radially inward so as to be disposed in the groove 61A of the tool bit 61. The locking member 43 disposed in the groove 61A is prevented from moving radially outward by the contact portion 44A. The elastic force of the elastic ring 49 causes the locking member 43 to be disposed in the locked position, thereby locking the tool bit 61.

[0142] The two-touch method refers to an attachment method in which the anvil 17 is attached to the tool bit 61 by inserting the tool bit 61 into the insertion hole 42 with the bit sleeve 44 in the allowable position, positioning at least a portion of the locking member 43 in the groove 61A of the tool bit 61, and then positioning the bit sleeve 44 in the blocking position. When the tool bit 61 is inserted into the insertion hole 42 with the bit sleeve 44 in the allowable position, the locking member 43 is pushed radially outward by the tapered surface 61B provided at the rear end of the tool bit 61. Because the bit sleeve 44 is in the allowable position, the locking member 43 is pushed by the tool bit 61, thereby releasing it from the locked position and moving it to the unlocked position. When the tool bit 61 is inserted into the insertion hole 42 until the groove 61A of the tool bit 61 faces the locking member 43 in the unlocked position, the locking member 43 moves radially inward to be positioned in the groove 61A via the through hole 51. After the locking member 43 is placed in the groove 61A, the bit sleeve 44 is moved to the blocking position, whereby the locking member 43 placed in the groove 61A is prevented from moving radially outward by the contact portion 44A. When the locking member 43 is placed in the lock position, the bit 61 is locked.

[0143] When removing the tool bit 61 attached to the anvil 17 from the insertion hole 42, the operator operates the operating member 45 so that the bit sleeve 44 is positioned in the permissible position. By removing the tool bit 61 from the insertion hole 42 with the bit sleeve 44 positioned in the permissible position, the locking member 43 is pushed radially outward by the outer surface of the tool bit 61, escapes from the groove portion 61A of the tool bit 61, and moves to the release position. With the locking member 43 positioned in the release position, the operator can remove the tool bit 61 from the insertion hole 42.

[0144] <Power tool operation> Next, the operation of the power tool 1 will be described. For example, when performing a screw tightening operation on a workpiece, the bit 61 to be used for the screw tightening operation is inserted into the insertion hole 42 of the anvil 17. The bit 61 inserted into the insertion hole 42 is held by the tool holding mechanism 18. After the bit 61 is attached to the anvil 17, the operator grips the grip portion 2B with, for example, the right hand and pulls the trigger lever 9A with the index finger of the right hand. When the trigger lever 9A is pulled, power is supplied from the battery pack 20 to the motor 6, and the motor 6 is started. When the motor 6 is started, the rotor shaft 22B of the rotor 22 rotates. When the rotor shaft 22B rotates, the rotational force of the rotor shaft 22B is transmitted to the planetary gear 32 via the pinion gear 27. The planetary gear 32, engaged with the internal teeth of the internal gear 34, revolves around the pinion gear 27 while rotating on its axis. The planetary gear 32 is rotatably supported on the spindle 15 via a pin 33. Due to the revolution of the planetary gear 32, the spindle 15 rotates at a rotational speed lower than the rotational speed of the rotor shaft portion 22B.

[0145] When the spindle 15 rotates while the inner hammer 35 and the anvil protrusion 17B are in contact with each other, the anvil 17 rotates together with the inner hammer 35 and the spindle 15. As the anvil 17 rotates, the screw tightening operation progresses.

[0146] As the screw tightening operation progresses, if a load equal to or greater than a predetermined value acts on the anvil 17, the rotation of the anvil 17 and the inner hammer 35 stops. When the rotation of the inner hammer 35 stops, the rotation of the outer hammer 36 also stops. If the spindle 15 rotates while the rotation of the inner hammer 35 and outer hammer 36 is stopped, the inner hammer 35 moves rearward while rotating. As the inner hammer 35 moves rearward, contact between the inner hammer 35 and the anvil protrusion 17B is released. Although the outer hammer 36 rotates together with the inner hammer 35, even if the inner hammer 35 moves rearward relative to the hammer case 11, the outer hammer 36 does not move axially relative to the hammer case 11. After moving rearward, the inner hammer 35 moves forward while rotating due to the elastic force of the coil spring 39. In addition, the outer hammer 36 rotates together with the inner hammer 35. As the outer hammer 36 rotates, the inner hammer 35 moves forward while rotating, causing the anvil 17 to be struck in the rotational direction by the inner hammer 35 and the outer hammer 36. This causes the anvil 17 to rotate about the rotation axis AX with high torque, thereby tightening the screw into the workpiece with high torque.

[0147] <Effects> As described above, according to this embodiment, the power tool 1 includes the motor 6, the spindle 15 arranged forward of the motor 6 and rotated by the motor 6, the inner hammer 35 supported by the spindle 15, the outer hammer 36 arranged around the inner hammer 35 and rotating together with the inner hammer 35, the anvil 17 struck in the rotational direction by the inner hammer 35, the hammer case 11 that houses the inner hammer 35 and the outer hammer 36, and the hammer bearing 29 held in the hammer case 11 and rotatably supporting the outer hammer 36.

[0148] In the above configuration, in the impact tool 1 including the inner hammer 35 and the outer hammer 36, the outer hammer 36 is rotatably supported by the hammer bearing 29 held in the hammer case 11, thereby preventing the power tool 1 from becoming larger. In particular, the axial length of the impact tool 1 is shortened. The axial length of the power tool 1 refers to the distance in the axial direction between the rear end of the rear cover 3 and the front end of the main body assembly 4A. In this embodiment, the front end of the main body assembly 4A includes the front end of the front cover 13.

[0149] In this embodiment, the power tool 1 includes a connecting member 37 that connects the inner hammer 35 and the outer hammer 36. The inner hammer 35 moves axially relative to the outer hammer 36 while being guided by the outer hammer 36 via the connecting member 37.

[0150] In the above configuration, the inner hammer 35 is movable in the axial direction, so the inner hammer 35 rotates while moving forward, and can strike the anvil 17 in the rotational direction. Since the outer hammer 36 does not move axially relative to the hammer case 11, the generation of axial vibrations in the impact tool 1 is suppressed.

[0151] In this embodiment, the spindle 15 has a spindle shaft portion 15A and a flange portion 15B provided at the rear of the spindle shaft portion 15A. The power tool 1 includes a coil spring 39 disposed around the spindle shaft portion 15A and generating an elastic force that moves the inner hammer 35 forward. The rear end of the coil spring 39 is supported by the flange portion 15B.

[0152] In the above configuration, the rear end of the coil spring 39 is supported by the flange portion 15B of the spindle 15, so that the axial length of the impact tool 1 is shortened.

[0153] In this embodiment, the spindle 15 and the outer hammer 36 may be spaced apart.

[0154] In the above configuration, the outer hammer 36 is connected to the inner hammer 35 via the connecting member 36, but is not directly connected to the spindle 15. This reduces the number of parts of the power tool 1 and prevents the power tool 1 from becoming larger.

[0155] In this embodiment, the outer hammer 36 is cylindrical, and the outer surface of the outer hammer 36 includes a large outer diameter surface 36A and a small outer diameter surface 36C that is located rearward of the large outer diameter surface 36A and connected to the large outer diameter surface 36A via a stepped surface 36B. The outer diameter of the outer hammer 36 at the large outer diameter surface 36A is larger than the outer diameter of the outer hammer 36 at the small outer diameter surface 36C. The hammer bearing 29 is disposed around the small outer diameter surface 36C.

[0156] In the above configuration, the hammer bearing 29 is disposed around the small outer diameter surface 36C, which prevents the power tool 1 from becoming large.

[0157] In this embodiment, the hammer case 11 has a cylindrical portion 11S, and the inner surface of the cylindrical portion 11S includes a small inner diameter surface 11D and a large inner diameter surface 11F that is located rearward of the small inner diameter surface 11D and is connected to the small inner diameter surface 11D via a stepped surface 11E. The inner diameter of the cylindrical portion 11S at the small inner diameter surface 11F is smaller than the inner diameter of the cylindrical portion 11S at the large inner diameter surface 11F. The front end surface of the hammer bearing 29 contacts both the stepped surface 36B of the outer hammer 36 and the stepped surface 11E of the hammer case 11. The power tool 1 includes a gear case 12 that is fixed to the rear end of the hammer case 11 and contacts the rear end surface of the hammer bearing 29.

[0158] In the above configuration, the front end surface of the hammer bearing 29 contacts the stepped surface 36B of the outer hammer 36 and the stepped surface 11E of the hammer case 11, and the rear end surface of the hammer bearing 29 contacts the gear case 12. This positions the hammer bearing 29.

[0159] [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.

[0160] Fig. 18 is a longitudinal sectional view showing the main body assembly 4B according to this embodiment, Fig. 19 is a transverse sectional view showing the main body assembly 4B according to this embodiment, and Fig. 20 is an exploded perspective view showing the main body assembly 4B according to this embodiment.

[0161] In the first embodiment described above, the anvil 17 to which the tip tool 61 is attached by either the one-touch method or the two-touch method has been described. In this embodiment, an anvil 170 to which the tip tool 61 is attached by the two-touch method and to which the tip tool 61 is not attached by the one-touch method will be described.

[0162] The main body assembly 4B has a hammer case 110, an anvil 170 housed in the hammer case 110, and an operating member 450 rotatably mounted on the front end of the hammer case 110.

[0163] The anvil 170 has a support hole 500 in which the locking member 43 is disposed, and an opening 510 that connects the support hole 500 and the insertion hole 42. The support hole 500 connects the outer surface of the anvil 170 and the inner surface of the insertion hole 42. The support hole 500 is inclined forward and radially inward. The cross-sectional shape of the support hole 500 is substantially circular. The locking member 43 moves through the support hole 500 while being guided by the inner surface of the support hole 500. The coil spring 490 is arranged to cover the radially outer opening of the support hole 500.

[0164] When the tool bit 61 is attached to the anvil 170, the operating member 450 is operated to position the bit sleeve 44 in the allowable position. The operating member 450 is operated by the operator to rotate the operating member 450 in the circumferential direction. With the bit sleeve 44 positioned in the allowable position, the tool bit 61 is inserted into the insertion hole 42. The locking member 43 is pushed radially outward by the tapered surface 61B provided at the rear end of the tool bit 61. By being pushed radially outward, the locking member 43 is moved from the locked position to the unlocked position. In this embodiment, a coil spring 490 is disposed around the anvil 170 instead of the elastic ring 49 described in the first embodiment. When the tool bit 61 is inserted into the insertion hole 42 until the groove 61A of the tool bit 61 faces the locking member 43 in the unlocked position, the elastic force of the coil spring 490 causes the locking member 43 to move radially inward to be disposed in the groove 61A through the through-hole 51.

[0165] After the locking member 43 is placed in the groove 61A, the operating member 450 is operated to place the bit sleeve 44 in the blocking position. The operating member 450 is operated by the operator to rotate it in the circumferential direction. When the bit sleeve 44 is moved to the blocking position, the locking member 43, which is placed in the groove 61A, is prevented from moving radially outward by the contact portion 44A. When the locking member 43 is placed in the locked position, its movement radially outward is prevented, and the tool bit 61 is locked.

[0166] When the contact portion 44A of the bit sleeve 44 and the locking member 43 are housed in the hammer case 11, the distance between the insertion opening at the front end of the insertion hole 42 and the locking member 43 when positioned at the locked position may be long. If the distance between the insertion opening of the insertion hole 42 and the locking member 43 is long, the type of tool bit 61 that can be locked by the locking member 43 may be limited. For example, if the tool bit 61 has a short distance between the groove 61A and the rear end of the tool bit 61, the locking member 43 may not be able to lock the tool bit 61. In this embodiment, the support hole 500 is inclined forward toward the inside in the radial direction. Therefore, the axial distance between the insertion opening at the front end of the insertion hole 42 and the locking member 43 when positioned at the locked position is short. Therefore, the locking member 43 can also lock a tool bit 61 with a short distance between the groove 61A and the rear end of the tool bit 61.

[0167] [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.

[0168] Fig. 21 is a longitudinal cross-sectional view showing a main body assembly 4C according to this embodiment, Fig. 22 is a transverse cross-sectional view showing a main body assembly 4C according to this embodiment, and Fig. 23 is an exploded perspective view showing a main body assembly 4C according to this embodiment.

[0169] In the first embodiment described above, the bit sleeve 44 moves in the axial direction when the operating member 45 is rotated in the circumferential direction. In the present embodiment, an example will be described in which the bit sleeve 44 moves in the axial direction when the operating member 451 is moved in the axial direction.

[0170] The main body assembly 4C according to this embodiment has the anvil 170 and the coil spring 490 described in the second embodiment. The main body assembly 4C according to this embodiment does not have the positioning member (47).

[0171] The operating member 451 is supported on the front end of the hammer case 11 so as to be axially movable. The operating member 451 has a ring portion 451A and a push portion 451B. The ring portion 451A is disposed radially outward from the boss portion 11H and the front cover 13. The push portion 451B is disposed radially inward from the ring portion 451A. The push portion 451B has a push surface 451E. The push surface 451E faces rearward. The push surface 451E includes the inner surface of a recess provided on the rear surface of the push portion 451B. The front end of the pin 52 contacts the push surface 451E. While in contact with the push surface 451E, the pin 52 moves axially as the operating member 451 moves. The bit washer 53 contacts each of the pin 52 and the bit sleeve 44.

[0172] When moving the bit sleeve 44 from the permissive position to the blocking position, the operator operates the operating member 45 so that the operating member 451 moves rearward. As the operating member 451 moves rearward, the pin 52 is pushed rearward by the push surface 451E of the operating member 451. When the pin 52 is pushed rearward by the push surface 451E, the bit sleeve 44 is pushed rearward by the pin 52 via the bit washer 53. The bit sleeve 44 moves rearward as it is pushed rearward by the pin 52. The bit sleeve 44 moves rearward against the elastic force of the sleeve spring 48. As the bit sleeve 44 moves rearward, it is positioned at the blocking position.

[0173] When moving the bit sleeve 44 from the blocking position to the allowing position, the operator operates the operating member 451 so that the operating member 451 moves forward. When the operating member 451 is moved forward, the bit sleeve 44 is moved forward by the elastic force of the sleeve spring 48. By moving the bit sleeve 44 forward, the bit sleeve 44 is positioned at the allowing position.

[0174] [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.

[0175] Figure 24 is a longitudinal cross-sectional view showing a main body assembly 4D according to this embodiment, and Figure 25 is a transverse cross-sectional view showing a main body assembly 4D according to this embodiment.

[0176] In the first embodiment described above, the operating member 45 is arranged outside the hammer case 11, and the bit sleeve 44 is housed in the hammer case 11. In this embodiment, an example will be described in which the operating member 452 is arranged outside the hammer case 11. In addition, in this embodiment, at least a part of the operating member 452 functions as a bit sleeve.

[0177] As shown in Figures 24 and 25, the main body assembly 4D has a hammer case 112, a gear case 122, a spindle bearing 282, a planetary gear 322, a pin 332, an internal gear 342, a spindle 152, a hammer 352, a ball 382, ​​a coil spring 392, an anvil 172, an anvil bearing 302, a lock member 432, an operating member 452, and a sleeve spring 482.

[0178] The hammer case 112 has a cylindrical portion 112S, a front plate portion 112T, and a boss portion 112H. The gear case 122 is fixed to the rear end portion of the hammer case 112. The gear case 122 holds a spindle bearing 282. The gear case 122 holds an internal gear 342.

[0179] The anvil 172 has an insertion hole 422, a support recess 502, and a through hole 512. The tool bit 61 is inserted into the insertion hole 422. The locking member 432 is disposed in the support recess 502. The through hole 512 connects the inner surface of the support recess 502 and the inner surface of the insertion hole 422.

[0180] The operating member 452 is movably supported by the hammer case 112. The operating member 452 is disposed on the outside of the hammer case 112. The operating member 452 is supported by the boss portion 112H and is movable in the front-rear direction. The operating member 452 functions as a bit sleeve. The operating member 452 has a contact portion 442A, a front plate portion 442B, an operating portion 442C, and a tubular portion 442D. The contact portion 442A is capable of contacting the locking member 432. The front plate portion 442B is disposed radially outward from the contact portion 442A and the tubular portion 442D. The front plate portion 442B is connected to both the contact portion 442A and the tubular portion 442D. The front plate portion 442B is disposed so as to extend radially outward from the rear end portion of the tubular portion 442D. The operating portion 442C is disposed around the boss portion 112H. The operating portion 442C is cylindrical. The front end of the operating portion 442C is connected to the outer edge of the front plate portion 442B. The cylindrical portion 442D is disposed around the front portion of the anvil 172.

[0181] The sleeve spring 482 generates an elastic force so that the operating member 452 moves to the blocking position. The sleeve spring 482 is disposed around the front portion of the anvil 172. In the radial direction, the sleeve spring 482 is disposed between the front portion of the anvil 172 and the cylindrical portion 442D. The rear end portion of the sleeve spring 482 contacts the front end portion of the contact portion 442A. The front end portion of the sleeve spring 482 is supported by the washer 62. The washer 62 is supported by the anvil 172.

[0182] The locking member 432 is movable between a locking position where it locks the tool bit 61 inserted into the insertion hole 422 and an unlocking position where it unlocks the tool bit 61. The contact portion 442A of the operating member 452 is movable between a blocking position where it blocks the locking member 432 from moving radially outward and an allowing position where it allows the locking member 432 to move radially outward.

[0183] In the axial direction, the anvil bearing 302 and at least a part of the operating member 452 overlap with each other. In this embodiment, in the axial direction, the anvil bearing 302 and at least a part of the operating portion 442C overlap with each other.

[0184] When moving contact portion 442A of operating member 452 from the blocking position to the allowing position, the operator operates operating member 452 so that operating member 452 moves forward. The operator can move operating member 452 forward by pinching operating portion 442C or cylindrical portion 442D with their fingers. By moving operating member 452 forward against the elastic force of sleeve spring 482, contact portion 442A is positioned at the allowing position.

[0185] When moving contact portion 442A of operating member 452 from the allowing position to the blocking position, the operator operates operating member 452 so that operating member 452 moves rearward. Operating member 452 is moved rearward by the elastic force of sleeve spring 482. By moving operating member 452 rearward, contact portion 442A is positioned at the blocking position.

[0186] [Fifth embodiment] A fifth 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.

[0187] Figure 26 is a longitudinal cross-sectional view showing a main body assembly 4E according to this embodiment, and Figure 27 is a transverse cross-sectional view showing a main body assembly 4E according to this embodiment.

[0188] In the first embodiment described above, the operating member 45 is arranged outside the hammer case 11, and the bit sleeve 44 is housed in the hammer case 11. In the present embodiment, an example will be described in which a portion of the operating member 453 is arranged outside the hammer case 11, a portion of the operating member 453 is arranged inside the hammer case 11, and the portion of the operating member 453 arranged inside the hammer case 11 functions as the bit sleeve.

[0189] The main body assembly 4E has an anvil 173 housed in the hammer case 11 and an operating member 453 movably supported on the anvil 173.

[0190] The anvil 173 has an insertion hole 423, a support recess 503, and a through hole 513. The locking member 43 is disposed in the support recess 503. The through hole 513 connects the inner surface of the support recess 503 and the inner surface of the insertion hole 423.

[0191] The operating member 453 has a tubular portion 443A, an operating portion 443B, and a recessed portion 443C. The tubular portion 443A is arranged around the anvil 173. At least a portion of the tubular portion 443A is housed in the hammer case 11. The rear end portion of the tubular portion 443A is capable of contacting the locking member 43. The operating portion 443B is arranged on the outside of the hammer case 11. The recessed portion 443C is arranged on the inside of the hammer case 11. The recessed portion 443C is provided on the inner surface of the tubular portion 443A. The recessed portion 443C is provided so as to be recessed radially outward from the inner surface of the tubular portion 443A.

[0192] A sleeve spring 483 is disposed behind the cylindrical portion 443A. The sleeve spring 483 is disposed around the anvil 173. The sleeve spring 483 generates an elastic force that moves the operating member 453 forward. The sleeve spring 483 generates an elastic force that moves the operating member 453 to the blocking position.

[0193] In the radial direction, at least a portion of the operating member 453 is disposed between the inner hammer 35 and the anvil 173. In the radial direction, at least a portion of the operating member 453 is disposed between the anvil bearing 30 and the anvil 173. In the radial direction, at least a portion of the operating member 453 is disposed rearward of the anvil bearing 30. The locking member 43 is disposed rearward of the anvil bearing 30. In the axial direction, the inner hammer 35 and the locking member 43 overlap.

[0194] The locking member 43 is movable between a locking position where it locks the tool bit 61 inserted in the insertion hole 423 and an unlocking position where it unlocks the tool bit 61. The operating member 453 is supported on the anvil 173 so as to be movable in the axial direction. The operating member 453 is movable between a blocking position where it blocks radially outward movement of the locking member 43 and an allowing position where it allows radially outward movement.

[0195] When moving the operating member 453 from the blocking position to the allowing position, the operator operates the operating member 453 so that the operating member 453 moves rearward. For example, the operator can move the operating member 453 rearward by pinching the operating portion 443B with their fingers. The operating member 453 is moved rearward against the elastic force of the sleeve spring 483, whereby the operating member 453 is positioned at the allowing position. When the operating member 453 is positioned at the allowing position, the locking member 43 can move radially outward. The locking member 43 that has moved radially outward is positioned inside the recess 443C.

[0196] When operating member 453 is to be moved from the permitting position to the blocking position, the operator operates operating portion 443B so that operating member 453 moves forward. Operating member 453 is moved forward by the elastic force of sleeve spring 483. By moving operating member 453 forward, operating member 453 is disposed in the blocking position.

[0197] [Sixth embodiment] A sixth 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.

[0198] Figure 28 is a longitudinal cross-sectional view showing a main body assembly 4F according to this embodiment, and Figure 29 is a transverse cross-sectional view showing a main body assembly 4F according to this embodiment.

[0199] In the first embodiment described above, an example has been described in which first surface 17G on the front surface of anvil protrusion 17B comes into contact with at least a part of bearing holder 31, and second surface 17J on the front surface of anvil protrusion 17B comes into contact with bearing holder 31. In the present embodiment, an example will be described in which ring member 314 is disposed in front of anvil protrusion 174B of anvil 174, first surface 174G on the front surface of anvil protrusion 174B comes into contact with ring member 314, and second surface 174J on the front surface of anvil protrusion 174B comes into contact with ring member 314.

[0200] As shown in Figures 28 and 29, the main body assembly 4F has a hammer case 114, a gear case 124, a spindle bearing 284, a planetary gear 324, a pin 334, an internal gear 344, a spindle 154, a hammer 354, a ball 384, a coil spring 394, an anvil 174, an anvil bearing 304, and a tool holding mechanism 184.

[0201] The anvil 174 has an anvil shaft portion 174A and an anvil protrusion portion 174B. An insertion hole 424 into which the tip tool 61 is inserted is provided in the anvil shaft portion 174A.

[0202] The front surface of the anvil protrusion 174B includes a first surface 174G and a second surface 174J that is connected to the first surface 174G via a stepped surface 174H. The second surface 174J is located rearward of the first surface 174G. The first surface 174G is located radially outward of the second surface 174J. In this embodiment, a recess is formed on the front surface of the anvil protrusion 174B. The first surface 174G is located radially outward of the recess. The stepped surface 174H includes a portion of the inner surface of the recess. The second surface 174J includes a portion of the inner surface of the recess.

[0203] The ring member 314 is positioned in contact with the first surface 174G. The first surface 174G and at least a portion of the ring member 314 are in contact. The second surface 174J and the ring member 314 are separated. The anvil 174 rotates with the first surface 174G and the rear surface of the ring member 314 in contact.

[0204] The ring member 314 is made of a synthetic resin such as nylon resin. The ring member 314 is supported by the hammer case 114. The ring member 314 may be fixed to the hammer case 114, or may be movably supported by the hammer case 114. In this embodiment, the ring member 314 is supported by the hammer case 114 rotatably about the rotation axis AX.

[0205] [Seventh embodiment] A seventh embodiment will be described. 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 those components will be simplified or omitted.

[0206] Figure 30 is a longitudinal cross-sectional view showing a main body assembly 4G according to this embodiment, Figure 31 is a transverse cross-sectional view showing a main body assembly 4G according to this embodiment, and Figure 32 is a front perspective view showing a main body assembly 4G according to this embodiment.

[0207] In the first embodiment described above, the main body assembly 4A constitutes a part of the impact driver. In this embodiment, an example will be described in which the main body assembly 4G constitutes a part of the impact wrench.

[0208] The main body assembly 4G has an anvil 175. The main body assembly 4G according to this embodiment does not have a tool holding mechanism 18. The main body assembly 4G according to this embodiment is equivalent to the main body assembly 4A described in the first embodiment above in terms of components other than the anvil 175.

[0209] The anvil 175 has an anvil shaft portion 175A and an anvil protrusion portion 175B that protrudes radially outward from the anvil shaft portion 175A. The anvil protrusion portion 175B is struck by the inner hammer 35 in the rotational direction.

[0210] The anvil shaft portion 175A includes a rear shaft portion 175Ar that is positioned rearward of the anvil protrusion 175B, and a front shaft portion 175Af that is positioned forward of the anvil protrusion 175B. The length of the rear shaft portion 175Ar may be longer or shorter than the length of the front shaft portion 175Af. The rear shaft portion 175Ar is inserted inside the spindle 15. A rear end portion 175R of the anvil shaft portion 175A is positioned rearward of the ball 38. A front end portion 175F of the anvil shaft portion 175A is positioned forward of the front cover 13. A socket is attached to the front shaft portion 175Af as an end tool.

[0211] [Other embodiments] In the above-described embodiment, the power source of the power tool 1 does not have to be the battery pack 20, and may be a commercial power source (AC power source). [Explanation of symbols]

[0212] 1...power tool, 2...housing, 2A...motor housing, 2B...grip, 2C...battery holder, 2L...left housing, 2R...right housing, 2S...screw, 3...rear cover, 3S...screw, 4A...main body assembly, 4B...main body assembly, 4C...main body assembly, 4D...main body assembly, 4E...main body assembly, 4F...main body assembly, 4G...main body assembly, 5...battery mounting section, 6...motor, 7...fan, 7A...intake port, 7B...exhaust port, 7C...bush, 8...controller, 8A...circuit board, 8B...case, 9...trigger switch, 9A...trigger lever, 9B...switch body, 10...forward / reverse switching lever, 11...hammer case, 11A...small outer diameter surface, 11B...step surface, 11C...large outer diameter surface, 11D...small inner diameter surface, 11E...step surface, 11F...large inner diameter surface, 11G...convex portion, 11H... boss portion, 11J... screw hole, 11K... guide hole, 11L... recessed portion, 11M... recessed portion, 11S... cylindrical portion, 11T... front plate portion, 12... gear case, 12A... ring portion, 12B... rear plate portion, 12C... convex portion, 12D... recessed portion, 13... front cover, 13A... through hole, 14... reduction mechanism, 15... spindle, 15A... spindle shaft portion, 15B... flange portion, 15C... pin support portion, 15D...bearing holding portion, 15E...connecting portion, 15F...support hole, 15G...support hole, 15H...spindle groove, 15J...support hole, 16...impact mechanism, 17...anvil, 17A...anvil shaft portion, 17B...anvil protrusion portion, 17Ar...rear shaft portion, 17Af...front shaft portion, 17F...front end portion, 17G...first surface, 17H...step surface, 17J...second surface, 17K...groove, 17R...rear end portion, 18...Tool holding mechanism, 19...Screw, 20...Battery pack, 21...Stator, 21A...Stator core, 21B...Rear insulator, 21C...Front insulator, 21D...Coil, 21E...Crossover, 22...Rotor, 22A...Rotor core portion, 22B...Rotor shaft portion, 22C...Rotor magnet, 22D...Sensor magnet, 23...Sensor board, 23S...Screw, 24...Rotor bearing, 25...Rotor bearing, 26...Bearing holder, 27...Pinion gear, 28...Spindle bearing, 29...Hammer bearing, 30...Anvil bearing, 31...Bearing holder, 31A...First part, 31B...Second part, 31C...Third part, 32...planetary gear, 33...pin, 34...internal gear, 34A...convex portion, 35...inner hammer, 35A...hammer main body portion, 35B...hammer protrusion portion, 35C...concave portion, 35D...retaining groove, 35E...hammer groove, 36...outer hammer, 36A...large outer diameter surface, 36B...step surface, 36C...small outer diameter surface, 36D...guide groove, 37...connecting member, 38...ball, 39...coil spring, 40...washer, 41...ball, 42...insertion hole, 43...locking member, 44...bit sleeve, 44A...contact portion, 44B...tubular portion, 44C...operating portion, 45...operating member, 45A...ring portion, 45B... Cam portion, 45C...recess, 45D...protrusion, 45E...cam surface, 46...transmission mechanism (conversion mechanism), 47...positioning member, 47A...body portion, 47B...protrusion, 48...sleeve spring, 49...elastic ring, 50...support recess, 51...through hole, 52...pin, 52A...groove, 53...bit washer, 53A...ring portion, 53B...protrusion, 53C...protrusion, 54...space, 55...O-ring, 56...O-ring, 57...O-ring, 58...O-ring, 59...washer, 60...washer, 61...tipped tool, 61A...groove portion, 61B...tapered surface, 62...washer, 110...hammer case, 112... Hammer case, 112H... boss portion, 112S... cylindrical portion, 112T... front plate portion, 114... hammer case, 122... gear case, 124... gear case, 152... spindle, 154... spindle, 170... anvil, 172... anvil, 173... anvil, 174... anvil, 174A... anvil shaft portion, 174B... anvil protrusion portion, 174G... first surface, 174H... stepped surface, 174J... second surface, 175... anvil, 175A... anvil shaft portion, 175Af... front shaft portion, 175Ar... rear shaft portion, 175B... anvil protrusion portion, 175F... front end portion, 1 75R...rear end portion, 184...tool holding mechanism, 282...spindle bearing, 284...spindle bearing, 302...anvil bearing, 304...anvil bearing, 314...ring member, 322...planetary gear, 324...planetary gear, 332...pin, 334...pin, 342...internal gear, 344...internal gear, 352...hammer, 354...hammer, 382...ball, 384...ball, 392...coil spring, 394...coil spring, 422...insertion hole, 423...insertion hole, 424...insertion hole, 442A...contact portion, 442B...front plate portion,442C...operation portion, 442D...tubular portion, 432...locking member, 443A...tubular portion, 443B...operation portion, 443C...recess, 450...operation member, 451...operation member, 451A...ring portion, 451B...push portion, 451E...push surface, 452...operation member, 453...operation member, 482...sleeve spring, 483...sleeve spring, 490...coil spring, 500...support hole, 502...support recess, 503...support recess, 510...opening, 512...through hole, 513...through hole, AX...rotation axis, D1...distance, D2...distance, Lf...length, Lr...length.

Claims

1. A motor; a spindle disposed forward of the motor and rotated by the motor; an inner hammer supported by the spindle; an outer hammer disposed around the inner hammer and rotating together with the inner hammer; an anvil that is struck in a rotational direction by the inner hammer; a hammer case that houses the inner hammer and the outer hammer; a bearing held by the hammer case and rotatably supporting the outer hammer; a connecting member that connects the inner hammer and the outer hammer, the spindle has a spindle shaft portion and a flange portion provided at a rear portion of the spindle shaft portion, The rear end of the outer hammer is disposed around the flange portion, and the rear end of the outer hammer and the flange portion are spaced apart in the radial direction. Impact tool.

2. a connecting member that connects the inner hammer and the outer hammer, The inner hammer moves in the axial direction relative to the outer hammer while being guided by the outer hammer via the connecting member. The impact tool according to claim 1 .

3. A coil spring is disposed around the spindle shaft portion and generates an elastic force that moves the inner hammer forward, The rear end of the coil spring is supported by the flange portion.

3. The impact tool according to claim 1 or 2.

4. The outer hammer is cylindrical, the outer surface of the outer hammer includes a large outer diameter surface and a small outer diameter surface that is disposed rearward of the large outer diameter surface and is connected to the large outer diameter surface via a stepped surface, an outer diameter of the outer hammer at the large outer diameter surface is larger than an outer diameter of the outer hammer at the small outer diameter surface; The bearing is disposed around the small outer diameter surface. An impact tool according to any one of claims 1 to 3.

5. The hammer case has a cylindrical portion, the inner surface of the cylindrical portion includes a small inner diameter surface and a large inner diameter surface that is disposed rearward of the small inner diameter surface and is connected to the small inner diameter surface via a stepped surface, an inner diameter of the cylindrical portion at the small inner diameter surface is smaller than an inner diameter of the cylindrical portion at the large inner diameter surface; a front end surface of the bearing contacts the stepped surface of the outer hammer and the stepped surface of the hammer case, a gear case fixed to a rear end of the hammer case and in contact with a rear end surface of the bearing; 5. The impact tool according to claim 4.

6. A motor; a spindle disposed forward of the motor and rotated by the motor, the spindle having a spindle shaft portion and a flange portion provided at a rear portion of the spindle shaft portion; an inner hammer supported by the spindle; an outer hammer disposed around the inner hammer and rotating together with the inner hammer; an anvil that is struck in a rotational direction by the inner hammer; a hammer case that houses the inner hammer and the outer hammer; a bearing held by the hammer case and rotatably supporting the outer hammer; a coil spring disposed around the spindle shaft portion and generating an elastic force that moves the inner hammer forward, The rear end of the coil spring is supported by the flange portion. Impact tool.

Images