Electric tool and impact tool

Abstract

To suppress the increase in the full length of an electric tool by a screw fixing a housing.SOLUTION: An electric tool includes: a motor; a motor storage part for storing the motor; a rotary mechanism part which is arranged in front of the motor, and includes an output part rotated on the basis of the rotation force of the motor; a rotary mechanism case which is arranged in front of the motor storage part, and stores at least a part of the rotary mechanism part; and a screw member which reaches the rotary mechanism case from the rear of the motor storage part, and mutually fixes the motor storage part and the rotary mechanism case. The motor is fixed together with the motor storage part and the rotary mechanism case, by a screw member.SELECTED DRAWING: Figure 18

Description

[Technical Field]

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

[0002] In the technical field of power tools, a power tool such as that disclosed in Patent Document 1 is known. In Patent Document 1, a motor and a rotation mechanism including a transmission are arranged front to back and housed in a pair of housings separated into left and right sections. The pair of housings are fixed to each other by screws provided so as to cross the space between the motor and the rotation mechanism from left to right. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 9,450,472 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional power tools, a space is provided between the motor and the rotation mechanism to accommodate the screws that secure the left and right housings together, which increases the overall length of the part that rotates the output unit.

[0005] The technology disclosed in this specification aims to prevent the overall length of the power tool from increasing due to screws used to fasten the housing. [Means for solving the problem]

[0006] This specification discloses a power tool. The power tool may include a motor, a motor housing that houses the motor, a rotation mechanism that is disposed forward of the motor and includes an output unit that rotates based on the rotational force of the motor, a rotation mechanism case that is disposed forward of the motor housing and houses at least a portion of the rotation mechanism, and a screw member that extends from behind the motor housing to the rotation mechanism case and secures the motor housing and the rotation mechanism case to each other. The motor may be secured together with the motor housing and the rotation mechanism case by the screw member. [Effects of the Invention]

[0007] According to the technology disclosed in this specification, it is possible to prevent the overall length of the power tool from increasing due to the screws that secure the housing. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front perspective view showing a power tool according to an embodiment. [Figure 2] FIG. 2 is a side view showing the power tool according to the embodiment. [Figure 3] FIG. 3 is a vertical cross-sectional view showing the power tool according to the embodiment. [Figure 4] FIG. 4 is a vertical cross-sectional view showing the upper part of the power tool according to the embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing the upper part of the power tool according to the embodiment. [Figure 6] FIG. 6 is an exploded perspective view showing the power tool according to the embodiment. [Figure 7] FIG. 7 is an exploded perspective view showing a light assembly according to the embodiment. [Figure 8] FIG. 8 is a rear perspective view showing the bearing holding member and the spindle according to the embodiment. [Figure 9] FIG. 9 is an exploded perspective view from the front showing the bearing and spindle support structure according to the embodiment. [Figure 10] FIG. 10 is an exploded perspective view from the rear showing the bearing and spindle support structure according to the embodiment. [Figure 11] FIG. 11 is a vertical cross-sectional view showing the surrounding structure of the bearing holding member according to the embodiment. [Figure 12] FIG. 12 is an exploded perspective view from the front showing the bearing holding member and the hammer case according to the embodiment. [Figure 13] FIG. 13 is a cross-sectional view showing the bearing holding member according to the embodiment from the front. [Figure 14] FIG. 14 is a schematic vertical cross-sectional view showing a modified example of the spindle bearing. [Figure 15] FIG. 15 is a schematic vertical cross-sectional view showing a modified example of a rotor bearing. [Figure 16] FIG. 16 is a schematic vertical cross-sectional view showing a first modified example of a support portion of a rotor bearing. [Figure 17] FIG. 17 is a schematic vertical cross-sectional view showing a second modified example of a support portion of a rotor bearing. [Figure 18] FIG. 18 is an exploded perspective view from the front showing the hammer case and the rear case according to the embodiment. [Figure 19] FIG. 19 is an exploded perspective view from the rear showing the hammer case and the rear case according to the embodiment. [Figure 20] FIG. 20 is a cross-sectional view showing a cross section passing through the screw member connecting the hammer case and the rear case. [Figure 21] FIG. 21 is a perspective view of the rear case according to the embodiment, seen from the front. [Figure 22] FIG. 22 is a perspective view of the motor according to the embodiment, seen from the front. [Figure 23] FIG. 23 is a perspective cross-sectional view showing a cross section passing through the stator core. [Figure 24] FIG. 24 is an exploded perspective view showing a housing according to the embodiment. [Figure 25] FIG. 25 is a perspective view showing the left housing according to the embodiment. [Figure 26] FIG. 26 is a perspective view showing the right housing according to the embodiment. [Figure 27]FIG. 27 is an exploded perspective view showing the connection portion between the left and right housings. [Figure 28] FIG. 28 is an exploded perspective view showing the rear case, the left housing, and the right housing according to the embodiment. [Figure 29] FIG. 29 is a vertical cross-sectional view for explaining dimensions of each part of the power tool according to the embodiment. [Figure 30] FIG. 30 is a vertical cross-sectional view showing an upper portion of a power tool according to another embodiment. [Figure 31] FIG. 31 is an exploded perspective view from the rear showing a bearing holding member, an internal gear, and a hammer case according to another embodiment. [Figure 32] FIG. 32 is a rear perspective view showing a power tool according to another embodiment. [Figure 33] FIG. 33 is a rear perspective view of a power tool according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] In one or more embodiments, the power tool may include a motor, a motor housing that houses the motor, a rotation mechanism that is disposed forward of the motor and includes an output unit that rotates based on a rotational force of the motor, a rotation mechanism case that is disposed forward of the motor housing and houses at least a portion of the rotation mechanism, and a screw member that extends from the rear of the motor housing to the rotation mechanism case and secures the motor housing and the rotation mechanism case to each other. The motor may be secured together with the motor housing and the rotation mechanism case by the screw member.

[0010] In the above configuration, the motor in the motor housing is fixed together with the motor housing and the rotation mechanism case by the longitudinal screw member that secures the motor housing and the rotation mechanism case to each other. This eliminates the need to provide space for arranging left-right screws between the motor and the rotation mechanism. Furthermore, compared to using separate screws to secure the motor housing, which houses the motor, to the rotation mechanism case and to secure the motor inside the motor housing, the space required for arranging the screws can be reduced. As a result, the overall length of the power tool can be prevented from increasing due to the screws that secure the housing. Furthermore, the number of parts and weight of the power tool can be reduced.

[0011] In one or more embodiments, the motor may include a rotor that rotates about a rotation axis and a stator that is disposed around the rotor. An outer periphery of the stator may be clamped between the motor housing and the rotation mechanism case by a screw member.

[0012] In the above configuration, the motor housing, the rotation mechanism case, and the stator can be fixed together with the same screw member.

[0013] In one or more embodiments, the stator may include a stator core, an insulator made of an electrical insulating material, and a coil disposed on the stator via the insulator. The stator core may be clamped between the motor housing and the rotating mechanism case by a screw member.

[0014] In the above configuration, the stator core of the stator can be fixed together with the motor housing and the rotation mechanism case using screws. The stator core is made of a laminate of steel plates or the like and has high rigidity, so the stator can be firmly fixed by clamping the stator core.

[0015] In one or more embodiments, the stator may include a stator core, an insulator made of an electrical insulating material, and a coil disposed on the stator via the insulator. The insulator may be sandwiched between the motor housing and the rotating mechanism case by a screw member.

[0016] In the above configuration, the insulator of the stator can be fixed to the motor housing and the rotation mechanism case with the screw member. Unlike a case where a separate member for clamping with the screw member is provided on the stator, for example, the number of parts does not increase, which reduces the number of parts and the weight of the power tool.

[0017] In one or more embodiments, the insulator may include a front insulator provided at a front portion of the stator core and a rear insulator provided at a rear portion of the stator core. Either the front insulator or the rear insulator may be clamped between the motor accommodating portion and the rotating mechanism case by a screw member.

[0018] In the above configuration, one of the front insulator and the rear insulator can be clamped by the screw member, while the other is not clamped. This reduces the influence of dimensional tolerances compared to when both the front insulator and the rear insulator are clamped.

[0019] In one or more embodiments, the power tool may further include a bearing holder having a rotor bearing that rotatably supports the rotor. The stator, together with the bearing holder, may be fixed between the motor housing and the rotation mechanism case by a screw member.

[0020] In the above-described configuration, not only the stator but also the bearing holder can be fixed to the motor housing and the rotation mechanism case with the same screw member, thereby more effectively reducing the number of parts and the weight of the power tool.

[0021] In one or more embodiments, the outer periphery of the stator and the bearing retaining member may be fixed by being sandwiched between the motor accommodating portion and the rotating mechanism case.

[0022] In the above configuration, the outer periphery of the stator and the bearing holding member are sandwiched and fixed between the motor accommodating portion and the rotation mechanism case, and the rotor bearing of the bearing holding member can support the rotor for rotation.

[0023] In one or more embodiments, the bearing retaining member may have a boss portion extending in the axial direction and through which the screw member is inserted. The outer periphery of the stator may be sandwiched between the motor accommodating portion and an end face of the boss portion.

[0024] In the above configuration, by providing a boss portion on the bearing holder, the axial force of the screw member can be effectively applied to the bearing holder to fix it. Furthermore, the boss portion of the bearing holder can be used as a contact portion for fixing the stator.

[0025] In one or more embodiments, the bearing retainer may have a rib protruding from the boss along the circumferential direction of the stator, and the outer periphery of the stator may contact an end face of the boss and an end face of the rib.

[0026] In the above configuration, providing a rib on the boss portion increases the rigidity of the boss portion. Furthermore, by bringing the end faces of the boss portion and the rib into contact with the outer periphery of the stator, the contact area between the bearing retainer and the stator can be increased. As a result, the stability of fixation by the screw member can be improved.

[0027] In one or more embodiments, the bearing retainer may include a retaining plate that retains the rotor bearing, and a peripheral wall that rises from the outer periphery of the retaining plate and has a boss formed thereon. The power tool may further include a fan that rotates together with the rotor in a space surrounded by the motor, the retaining plate, and the peripheral wall.

[0028] In the above configuration, the end face of the boss provided on the peripheral wall comes into contact with the stator, so the boss functions as a spacer that provides a gap between the motor (rotor and stator) and the holding plate of the bearing holding member. By placing a fan in the space thus formed, a structure that can efficiently cool the motor can be realized without the need for additional spacer members to adjust the positions of each component.

[0029] In one or more embodiments, the screw member may pass radially outward from the outer circumferential surface of the stator core.

[0030] In the above configuration, the screw member and the stator can be kept out of contact without providing any special structure between them, which prevents the stator core from coming into contact with the screw member during assembly or operation of the power tool, thereby preventing wear or peeling of the steel plate.

[0031] In one or more embodiments, the bearing retaining member may be made of metal or plastic.

[0032] In the above configuration, when a metal bearing holder is used, for example, high mechanical strength and high rigidity can be easily obtained, and when a resin bearing holder is used, it can be easily molded into a shape suitable for being fixed between the motor housing and the rotation mechanism case by a screw member.

[0033] In one or more embodiments, a plurality of screw members may be arranged around the circumference of the motor in the rotational direction.

[0034] In the above configuration, the motor can be firmly fixed without providing a separate screw dedicated to fixing the motor inside the motor housing portion.

[0035] In one or more embodiments, the rotation mechanism case may be made of metal. A screw hole into which a screw member is attached may be formed at a rear end of the rotation mechanism case.

[0036] In the above configuration, a metal case with high mechanical strength and rigidity can be used as the rotation mechanism case, so the motor housing and motor can be stably fixed. Also, for example, there is no need to embed metal nuts or the like only in the screw hole areas, and the screw holes can be formed directly in the rotation mechanism case.

[0037] In one or more embodiments, the impact tool may include a motor, a motor housing that houses the motor, a rotation mechanism that includes a hammer that is disposed forward of the motor and rotated about a rotation axis by the motor, and an anvil that is struck in the rotational direction by the hammer, a rotation mechanism case that is disposed forward of the motor housing and houses at least a portion of the rotation mechanism, and a screw member that extends from behind the motor housing to the rotation mechanism case and secures the motor housing and the rotation mechanism case to each other. At least a portion of the motor may be secured together with the motor housing and the rotation mechanism case by the screw member.

[0038] In the above configuration, the motor in the motor housing is fixed together with the motor housing and the rotation mechanism case by the longitudinal screw member that secures the motor housing and the rotation mechanism case to each other. This eliminates the need to provide space for arranging left-right screws between the motor and the rotation mechanism. Furthermore, compared to using separate screws to secure the motor housing, which houses the motor, to the rotation mechanism case and to secure the motor inside the motor housing, the space required for arranging the screws can be reduced. As a result, the overall length of the impact tool can be prevented from increasing due to the screws that secure the housing. Furthermore, the number of parts and weight of the impact tool can be reduced.

[0039] Hereinafter, an embodiment will be described with reference to the drawings. In the embodiment, the positional relationship of each part will be 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. The power tool 1 has a motor 6 as a power source.

[0040] In the embodiment, the direction parallel to the rotation axis AX of the motor 6 is referred to as the axial direction, the direction circumferentially around the rotation axis AX is referred to as the circumferential direction or rotation direction, and the radial direction of the rotation axis AX is referred to as the radial direction.

[0041] The rotation axis AX extends in the front-to-rear direction. One axial side is the front, and the other axial side is the rear. In addition, in the radial direction, a position closer to or approaching the rotation axis AX will be referred to as the radially inner side, and a position farther from or away from the rotation axis AX will be referred to as the radially outer side.

[0042] [Power tools] FIG. 1 is a front perspective view of a power tool 1 according to an embodiment. FIG. 2 is a side view of the power tool 1 according to an embodiment. FIG. 3 is a vertical cross-sectional view of the power tool 1 according to an embodiment. FIG. 4 is a vertical cross-sectional view of an upper portion of the power tool 1 according to an embodiment. FIG. 5 is a horizontal cross-sectional view of an upper portion of the power tool 1 according to an embodiment. FIG. 6 is an exploded perspective view of the power tool 1 according to an embodiment.

[0043] The power tool 1 is a rotary tool that rotates an output unit using a motor 6. In the embodiment, the power tool 1 is a screw tightening tool that tightens fastening members such as screws, bolts, and nuts by rotating the output unit. The power tool 1 may also be an electric drill that drills holes by rotating the output unit. In the embodiment, the power tool 1 is an impact tool, which is a type of screw tightening tool. One example of an impact tool is an impact driver.

[0044] The power tool 1 includes a housing 2, a rotation mechanism 3, a hammer case (rotation mechanism case) 4, and a motor 6. The rotation mechanism 3 includes a speed reducer 7, a spindle 8, a striking mechanism 9, and an anvil (output unit) 10. The power tool 1 also includes a tool holding mechanism 11, a fan 12, a battery mounting unit 13, a trigger lever 14, a forward / reverse rotation switch lever 15, an operation display unit 16, a mode switch 17, and a light assembly 18.

[0045] The housing 2 is made of synthetic resin. In this embodiment, the housing 2 is made of nylon. 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.

[0046] The housing 2 includes a rear case 2B disposed behind the left housing 2L and the right housing 2R. The rear case 2B is fixed to each of the hammer case 4, the left housing 2L, and the right housing 2R.

[0047] The housing 2 has a motor accommodating portion 21, a grip portion 22, a battery holding portion 23, and a case holding portion 24.

[0048] The motor accommodating section 21 accommodates the motor 6. The motor accommodating section 21 has a peripheral surface section 21A that surrounds the outer periphery of the motor 6 and a rear surface section 21B that covers the rear of the motor 6. The motor accommodating section 21 is provided in the rear case 2B. The peripheral surface section 21A is configured on the outer periphery of the rear case 2B, and the rear surface section 21B is configured on the rear surface of the rear case 2B. The motor 6 is disposed on the inner periphery side of the motor accommodating section 21, i.e., on the inner periphery side of the rear case 2B. The motor accommodating section 21 accommodates at least a portion of the fan 12. The fan 12 is disposed on the inner periphery side of the motor accommodating section 21. The motor accommodating section 21 accommodates at least a portion of the bearing holding member 5. The bearing holding member 5 is disposed on the inner periphery side of the motor accommodating section 21. The bearing holding member 5 is disposed within an opening at the front end of the motor accommodating section 21.

[0049] The case holder 24 is cylindrical. The case holder 24 houses at least a portion of the hammer case 4. The case holder 24 has openings on the front and rear. The case holder 24 covers the periphery of the hammer case 4 so that the anvil 10 protrudes forward. A portion of the hammer case 4 protrudes forward from the opening on the front of the case holder 24.

[0050] The grip portion 22 is connected to the case holding portion 24. In this embodiment, the grip portion 22 extends downward from the case holding portion 24. The grip portion 22 is also connected to the motor housing portion 21. The grip portion 22 extends downward from the motor housing portion 21. The trigger lever 14 and the forward / reverse switching lever 15 are provided on the upper portion of the grip portion 22. The grip portion 22 is held by the operator.

[0051] The battery holding portion 23 is connected to the lower end of the grip portion 22. The outer dimensions of the battery holding portion 23 in both the front-rear and left-right directions are larger than the outer dimensions of the grip portion 22. A battery pack 25 is detachably attached to the battery holding portion 23.

[0052] The grip portion 22 and the battery holding portion 23 have a split structure, and are provided on one side of the left housing 2L and the right housing 2R.

[0053] The rear case 2B is made of synthetic resin. The rear case 2B is disposed behind the case holding portion 24. The rear case 2B is disposed behind the hammer case 4. The rear case 2B is disposed so as to cover the opening at the rear end of the cylindrical case holding portion 24. The front end surface of the rear case 2B and the rear end surface of the case holding portion 24 face each other in the front-rear direction. The rear case 2B is fixed to the rear end of the hammer case 4 with four screw members 4S.

[0054] The rear case 2B has an intake port 19. The rear case 2B has an exhaust port 20. Air from the external space of the housing 2 flows into the internal space of the housing 2 through the intake port 19. Air from the internal space of the housing 2 flows out to the external space of the housing 2 through the exhaust port 20.

[0055] The hammer case 4 is made of metal. In this embodiment, the hammer case 4 is made of aluminum. The hammer case 4 is cylindrical. The hammer case 4 is arranged in front of the motor accommodating section 21. The hammer case 4 is arranged on the inner peripheral side of the case holding section 24. The hammer case 4 is arranged so as to fit into an opening at the front end of the rear case 2B. The hammer case 4 is connected to the rear case 2B. The hammer case 4 is fixed to the front end of the rear case 2B by four screw members 4S. The hammer case 4 has four boss portions 4H with screw holes formed therein into which the screw members 4S are attached.

[0056] A bearing retaining member 5 is disposed at the rear of the hammer case 4. The outer periphery of the bearing retaining member 5 fits into the opening at the rear end of the hammer case 4. The bearing retaining member 5 is fixed to the rear case 2B and the hammer case 4. The bearing retaining member 5 is fixed between the rear case 2B and the hammer case 4 by screw members 4S. The bearing retaining member 5 holds a spindle bearing 44 that supports the spindle 8. The bearing retaining member 5 holds a rotor bearing 39F that supports the rotor shaft portion 33 via the spindle 8. The bearing retaining member 5 is made of metal or resin. In this embodiment, the bearing retaining member 5 is made of metal, specifically aluminum.

[0057] The hammer case 4 is a rotation mechanism case that accommodates at least a part of the rotation mechanism 3. The hammer case 4 accommodates at least a part of the reduction mechanism 7, the spindle 8, the striking mechanism 9, and the anvil 10.

[0058] The hammer case 4 has a first cylindrical portion 4A and a second cylindrical portion 4B. The first cylindrical portion 4A is disposed around the striking mechanism 9. The second cylindrical portion 4B is disposed forward of the first cylindrical portion 4A. The outer diameter of the second cylindrical portion 4B is smaller than the outer diameter of the first cylindrical portion 4A.

[0059] At least a portion of the surface of the hammer case 4 is covered by the case holder 24. At least a portion of the surface of the hammer case 4 is covered by the hammer case cover 85. The case holder 24 and the hammer case cover 85 protect the hammer case 4. The case holder 24 and the hammer case cover 85 suppress contact between the hammer case 4 and objects around the hammer case 4. In the embodiment, substantially the entire surface of the hammer case 4 is covered by the case holder 24 and the hammer case cover 85.

[0060] The motor 6 is a power source for the power tool 1. The motor 6 is an inner rotor type brushless motor. The motor 6 has a stator 26 and a rotor 27. The stator 26 is supported by the motor housing portion 21. The stator 26 is disposed around the rotor 27. The rotor 27 rotates relative to the stator 26. The rotor 27 rotates around a rotation axis AX extending in the front-rear direction.

[0061] The stator 26 has a stator core 28, insulators, and coils 31. The insulators include a front insulator 29 and a rear insulator 30. A power line 26L (see FIG. 11) that supplies power to the coils 31 is connected to the stator 26. The stator 26 is connected to a controller 38 (see FIG. 3) via the power line 26L.

[0062] The stator core 28 is disposed radially outward of the rotor 27. The stator core 28 includes a plurality of stacked steel plates. The steel plates are metal plates whose main component is iron. The stator core 28 is annular. The stator core 28 has a plurality of teeth that support the coils 31.

[0063] The insulators are interposed between the stator core 28 and the coils 31. The front insulator 29 is provided in the front portion of the stator core 28. The rear insulator 30 is provided in the rear portion of the stator core 28. The front insulator 29 and the rear insulator 30 are each an electrical insulating member made of synthetic resin. The front insulator 29 is arranged so as to cover a portion of the surface of the teeth. The rear insulator 30 is arranged so as to cover a portion of the surface of the teeth.

[0064] The coils 31 are attached to the stator core 28 via the front insulators 29 and the rear insulators 30. Multiple coils 31 are arranged. The coils 31 are arranged around the teeth of the stator core 28 via the front insulators 29 and the rear insulators 30. The coils 31 and the stator core 28 are electrically insulated by the front insulators 29 and the rear insulators 30.

[0065] The rotor 27 rotates about a rotation axis AX. The rotor 27 includes a rotor core portion 32 and a rotor shaft portion 33.

[0066] The rotor core 32 and the rotor shaft 33 are both made of steel. The rotor shaft 33 protrudes in the front-to-rear direction from the end face of the rotor core 32. The rotor shaft 33 includes a front shaft portion 33F that protrudes forward from the front end face of the rotor core 32 and a rear shaft portion 33R that protrudes rearward from the rear end face of the rotor core 32.

[0067] The rotor core portion 32 has a rotor magnet (not shown) that extends in the axial direction from the front surface to the rear surface of the rotor core portion 32. The rotor magnet is disposed inside the rotor core portion 32.

[0068] A sensor board 37 is attached to the rear insulator 30. The sensor board 37 is fixed to the rear insulator 30 with screws 37S. As shown in FIG. 11, the sensor board 37 has a circuit board 37A and a rotation detection element 37B supported by the circuit board 37A. The circuit board 37A and the rotation detection element 37B are covered with molded resin 37C. A signal line 37L is connected to the sensor board 37. The sensor board 37 is connected to a controller 38 (see FIG. 3) via the signal line 37L. At least a portion of the sensor board 37 faces the rear end surface of the rotor core portion 32. The rotation detection element 37B detects the position of the rotor magnet, thereby detecting the position of the rotor 27 in the rotational direction.

[0069] The rotor shaft portion 33 is supported by rotor bearings. The rotor bearings include a front rotor bearing 39F that rotatably supports the front shaft portion 33F and a rear rotor bearing 39R that rotatably supports the rear shaft portion 33R. The rotor bearings 39F and 39R rotatably support the rotor 27.

[0070] The rotor bearing 39R is held by the rear case 2B. The rotor bearing 39F is held by the spindle 8. The front end of the rotor shaft 33 passes through the rotor bearing 39F and is disposed in the internal space of the hammer case 4. The front end of the rotor shaft 33 is connected to the rotation mechanism 3 inside the hammer case 4.

[0071] As described above, the rotation mechanism 3 includes the reduction mechanism 7, the spindle 8, the impact mechanism 9, and the anvil 10. The reduction mechanism 7 is disposed forward of the motor 6. A pinion gear 41 is formed at the front end of the rotor shaft 33. The pinion gear 41 is connected to at least a portion of the reduction mechanism 7. The rotor shaft 33 is connected to the reduction mechanism 7 via the pinion gear 41.

[0072] The reduction mechanism 7 is disposed on the front side of the bearing holding member 5. The reduction mechanism 7 is disposed inside the hammer case 4. The reduction mechanism 7 connects the rotor shaft portion 33 and the spindle 8. The reduction mechanism 7 transmits the rotation of the rotor 27 to the spindle 8. The reduction mechanism 7 rotates the spindle 8 at a rotational speed lower than the rotational speed of the rotor shaft portion 33. The reduction mechanism 7 includes a planetary gear mechanism.

[0073] The reduction mechanism 7 has a plurality of gears. The gears of the reduction mechanism 7 are driven by a rotor 27.

[0074] The reduction mechanism 7 has a plurality of planetary gears 42 arranged around the pinion gear 41, and an internal gear 43 arranged around the plurality of planetary gears 42. The pinion gear 41, the planetary gear 42, and the internal gear 43 are each housed in the hammer case 4. Each of the plurality of planetary gears 42 meshes with the pinion gear 41. The planetary gear 42 is rotatably supported on the spindle 8 via a pin 42P. The spindle 8 is rotated by the planetary gear 42. The internal gear 43 has internal teeth that mesh with the planetary gear 42. The internal gear 43 is fixed to the hammer case 4. A stepped portion is provided at the rear of the inner circumferential surface of the hammer case 4, and the internal gear 43 is arranged between the wall of the stepped portion and the bearing retaining member 5. The internal gear 43 is always non-rotatable relative to the hammer case 4 .

[0075] When the rotor shaft portion 33 is rotated by the drive of the motor 6, the pinion gear 41 rotates, and the planetary gear 42 revolves around the pinion gear 41. The planetary gear 42 revolves while meshing with the internal teeth of the internal gear 43. Due to the revolution of the planetary gear 42, the spindle 8 connected to the planetary gear 42 via the pin 42P rotates at a rotational speed lower than the rotational speed of the rotor shaft portion 33.

[0076] The spindle 8 is disposed forward of at least a portion of the motor 6. The spindle 8 is disposed forward of the stator 26. At least a portion of the spindle 8 is disposed forward of the rotor 27. At least a portion of the spindle 8 is disposed forward of the reduction mechanism 7. The spindle 8 is disposed rearward of the anvil 10.

[0077] The spindle 8 is a rotating member that is rotated by the rotor 27. The spindle 8 is rotated by the rotational force of the rotor 27 transmitted by the reduction mechanism 7. The spindle 8 transmits the rotational force of the motor 6 to the anvil 10 via the ball 48 and the hammer 47.

[0078] The spindle 8 has a flange portion 8A, a shaft portion 8B protruding forward from the flange portion 8A, and a retaining portion 8C. The flange portion 8A rotatably supports the planetary gear 42 via a pin 42P. The rotation axis of the spindle 8 coincides with the rotation axis AX of the motor 6. The spindle 8 rotates around the rotation axis AX. A retaining portion 8C is provided at the rear end of the spindle 8. The retaining portion 8C protrudes rearward from the flange portion 8A. The retaining portion 8C has a cylindrical shape. The retaining portion 8C is surrounded by a spindle bearing 44. The spindle 8 is rotatably supported by the spindle bearing 44.

[0079] The bearing holding member 5 is disposed around at least a portion of the circumference of the spindle 8. The bearing holding member 5 has an annular shape. The bearing holding member 5 holds a spindle bearing 44. The spindle bearing 44 is held on the inner circumferential surface of the bearing holding member 5. The spindle bearing 44 has an annular shape. The inner circumferential surface of the spindle bearing 44 contacts the spindle 8 to support the spindle 8.

[0080] The striking mechanism 9 is driven by a motor 6. The rotational force of the motor 6 is transmitted to the striking mechanism 9 via a reduction mechanism 7 and a spindle 8. The striking mechanism 9 strikes the anvil 10 in the rotational direction based on the rotational force of the spindle 8 rotated by the motor 6. The striking mechanism 9 has a hammer 47, a ball 48, a coil spring 49, and a washer 50. The striking mechanism 9 including the hammer 47, the ball 48, the coil spring 49, and the washer 50 is housed in the first cylindrical portion 4A of the hammer case 4.

[0081] The hammer 47 is disposed forward of the reduction mechanism 7. The hammer 47 is disposed around the spindle 8. The hammer 47 is held by the spindle 8. The ball 48 is disposed between the spindle 8 and the hammer 47. The hammer 47 has a cylindrical hammer body 47D and a hammer protrusion 47E provided at the front of the hammer body 47D. An annular recess 47C is provided on the rear surface of the hammer body 47D. The recess 47C is recessed forward from the rear surface of the hammer body 47D.

[0082] The hammer 47 is disposed around the shaft portion 8B of the spindle 8. The hammer 47 has a hole 47A in which the shaft portion 8B is disposed.

[0083] The hammer 47 is rotated by the motor 6. The rotational force of the motor 6 is transmitted to the hammer 47 via the reduction gear mechanism 7 and the spindle 8. The hammer 47 is rotated by the spindle 8. That is, the hammer 47 can rotate together with the spindle 8 based on the rotational force of the spindle 8 rotated by the motor 6. The rotation axis of the hammer 47, the rotation axis of the spindle 8, and the rotation axis AX of the motor 6 coincide with each other. The hammer 47 rotates around the rotation axis AX.

[0084] The washer 50 is disposed inside the recess 47C. The washer 50 is supported by the hammer 47 via a plurality of balls 51. The balls 51 are disposed forward of the washer 50. The balls 51 enable the washer 50 and the hammer 47 to move relatively in the rotational direction.

[0085] The coil spring 49 is disposed around the shaft portion 8B. The rear end of the coil spring 49 is supported by the flange portion 8A. The front end of the coil spring 49 is disposed inside the recess 47C and is supported by a washer 50. The coil spring 49 constantly generates a biasing force (elastic force) that moves the hammer 47 forward.

[0086] The ball 48 is made of a metal such as steel. The ball 48 is disposed between the shaft portion 8B and the hammer 47. The spindle 8 has a spindle groove 8D in which at least a portion of the ball 48 is disposed. The spindle groove 8D is provided on a portion of the outer circumferential surface of the shaft portion 8B. The hammer 47 has a hammer groove 47B in which at least a portion of the ball 48 is disposed. The hammer groove 47B is provided on a portion of the inner surface of the hammer 47. The ball 48 is disposed between the spindle groove 8D and the hammer groove 47B. The ball 48 can roll inside the spindle groove 8D and inside the hammer groove 47B. The hammer 47 is movable along with the ball 48. The spindle 8 and the hammer 47 can move relative to each other in the axial direction and the rotational direction within a movable range defined by the spindle groove 8D and the hammer groove 47B.

[0087] The anvil 10 is disposed forward of the motor 6. The anvil 10 is an output part of the power tool 1 that rotates based on the rotational force of the rotor 27. At least a portion of the anvil 10 is disposed forward of the hammer 47. The anvil 10 has a tool hole 10A into which a tool bit is inserted. The tool hole 10A is provided at the front end of the anvil 10. The tool bit is attached to the anvil 10.

[0088] The anvil 10 has an anvil protrusion 10B. The anvil protrusion 10B is provided at the rear end of the anvil 10. The anvil protrusion 10B protrudes rearward from the rear end of the anvil 10. The spindle 8 is arranged behind the anvil 10. A spindle recess 8E is provided at the front end of the shaft 8B. The anvil protrusion 10B is arranged in the spindle recess 8E. The spindle recess 8E is recessed rearward from the front end face of the shaft 8B to receive the anvil protrusion 10B.

[0089] The anvil 10 has a rod-shaped anvil shank 10C and an anvil protrusion 10D. The tool hole 10A is provided at the front end of the anvil shank 10C. A tool tip is attached to the anvil shank 10C. The anvil protrusion 10D is provided at the rear end of the anvil 10. The anvil protrusion 10D protrudes radially outward from the rear end of the anvil shank 10C.

[0090] The anvil 10 is rotatably supported by a bearing 46. The rotation axis of the anvil 10, the rotation axis of the hammer 47, the rotation axis of the spindle 8, and the rotation axis AX of the motor 6 are all coincident. The anvil 10 rotates around the rotation axis AX. The bearing 46 is arranged around the anvil shaft portion 10C. The bearing 46 is arranged inside the second cylindrical portion 4B of the hammer case 4. The bearing 46 is held in the second cylindrical portion 4B of the hammer case 4. The bearing 46 rotatably supports the anvil shaft portion 10C.

[0091] An O-ring 45 is disposed between the bearing 46 and the anvil shaft 10 C. The O-ring 45 contacts the outer periphery of the anvil shaft 10 C and the inner periphery of the bearing 46 .

[0092] Two bearings 46 are arranged in the axial direction. The bearings 46 are ball bearings. The bearings 46 have an inner ring, balls, and an outer ring. The inner ring of the bearing 46 contacts the O-ring 45. The balls of the bearing 46 are arranged between the inner ring and the outer ring in the radial direction. The balls of the bearing 46 contact each of the inner ring and the outer ring. Multiple balls of the bearing 46 are arranged in the circumferential direction. The outer ring is arranged radially outward of the inner ring and the balls. The outer ring of the bearing 46 contacts the inner circumferential surface of the second cylindrical portion 4B.

[0093] At least a portion of the hammer 47 is capable of contacting the anvil protrusion 10D. A hammer protrusion 47E that protrudes forward is provided at the front of the hammer 47. The hammer protrusion 47E and the anvil protrusion 10D are capable of contacting each other. When the motor 6 is driven while the hammer 47 and the anvil protrusion 10D are in contact with each other, the anvil 10 rotates together with the hammer 47 and the spindle 8.

[0094] The anvil 10 is struck in the rotational direction by the hammer 47. For example, during a screw tightening operation, if the load acting on the anvil 10 becomes too high, a situation may occur in which the anvil 10 cannot be rotated by the load of the coil spring 49 alone. When the load of the coil spring 49 alone cannot rotate the anvil 10, the rotation of the anvil 10 and the hammer 47 stops. The spindle 8 and the hammer 47 are movable relative to each other in the axial and circumferential directions via the ball 48. Even after the rotation of the hammer 47 stops, the rotation of the spindle 8 continues due to the power generated by the motor 6. When the spindle 8 rotates while the rotation of the hammer 47 is stopped, the ball 48 moves rearward while being guided by the spindle groove 8D and the hammer groove 47B. The hammer 47 receives force from the ball 48 and moves rearward along with the ball 48. In other words, when the rotation of the anvil 10 is stopped, the hammer 47 moves rearward due to the rotation of the spindle 8. As the hammer 47 moves rearward, the contact between the hammer 47 and the anvil protrusion 10D is released.

[0095] As described above, the coil spring 49 constantly generates a biasing force that moves the hammer 47 forward. After moving rearward, the hammer 47 moves forward due to the biasing force of the coil spring 49. As the hammer 47 moves forward, it receives a rotational force from the ball 48. That is, the hammer 47 moves forward while rotating. As the hammer 47 moves forward while rotating, it comes into contact with the anvil protrusion 10D while rotating. As a result, the anvil protrusion 10D is struck in the rotational direction by the hammer protrusion 47E of the hammer 47. Both the power of the motor 6 and the inertial force of the hammer 47 act on the anvil 10. Therefore, the anvil 10 can rotate around the rotation axis AX with high torque.

[0096] The tool holding mechanism 11 is disposed around the front portion of the anvil 10. The tool holding mechanism 11 holds a tool bit inserted into a tool hole 10A of the anvil 10. The tool holding mechanism 11 is capable of attaching and detaching the tool bit.

[0097] The tool holding mechanism 11 includes a ball 71 , a leaf spring 72 , a sleeve 73 , a coil spring 74 , a positioning member 75 , a ring spring 77 , and a washer 78 .

[0098] The anvil 10 has a support recess 76 that supports the ball 71. The support recess 76 is formed on the outer circumferential surface of the anvil shank 10C. Two support recesses 76 are formed in the anvil shank 10C.

[0099] The balls 71 are movably supported on the anvil 10. The balls 71 are arranged in the support recesses 76. The balls 71 are arranged one per support recess 76.

[0100] A through hole connecting the inner surface of the support recess 76 and the inner surface of the tool hole 10A is formed in the anvil shank 10C. With the ball 71 supported by the support recess 76, at least a portion of the ball 71 is positioned inside the tool hole 10A. The ball 71 can fix a tool bit inserted into the tool hole 10A. The ball 71 is movable between an engagement position where the tool bit is fixed and a release position where the tool bit is released from the engagement position.

[0101] The leaf spring 72 generates an elastic force that moves the ball 71 to the engagement position. The leaf spring 72 is disposed around the anvil shaft portion 10C. The leaf spring 72 generates an elastic force that moves the ball 71 radially inward.

[0102] The sleeve 73 is a cylindrical member. The sleeve 73 is disposed around the anvil shaft 10C. The sleeve 73 is axially movable around the anvil shaft 10C. The sleeve 73 can prevent the ball 71, which is disposed in the engagement position, from escaping from the engagement position. By moving the sleeve 73 in the axial direction, the ball 71 can be changed to a state in which it can be moved from the engagement position to the release position.

[0103] The sleeve 73 is movable around the anvil shaft 10C between a blocking position where the balls 71 are prevented from moving radially outward and an allowing position where the balls 71 are allowed to move radially outward.

[0104] By positioning the sleeve 73 in the blocking position, the ball 71, which is positioned in the engagement position, is prevented from moving radially outward. In other words, by positioning the sleeve 73 in the blocking position, the ball 71, which is positioned in the engagement position, is prevented from escaping from the engagement position. By positioning the sleeve 73 in the blocking position, the bit is maintained in a state where it is fixed by the ball 71.

[0105] When the sleeve 73 is moved to the permissible position, the ball 71, which is positioned at the engagement position, is allowed to move radially outward. When the sleeve 73 is moved to the permissible position, the ball 71 is allowed to move from the engagement position to the release position. In other words, when the sleeve 73 is placed at the permissible position, the ball 71, which is positioned at the engagement position, is allowed to move out of the engagement position. When the sleeve 73 is placed at the permissible position, the state in which the tool bit is fixed by the ball 71 can be released.

[0106] The coil spring 74 generates an elastic force that moves the sleeve 73 to the blocking position. The coil spring 74 is disposed around the anvil shaft 10C. The blocking position is set rearward of the allowable position. The coil spring 74 generates an elastic force that moves the sleeve 73 rearward. The front end of the coil spring 74 contacts a washer 78. The washer 78 is supported from the front by a ring spring 77 attached to the anvil shaft 10C. As a result, the coil spring 74 is supported by the ring spring 77 via the washer 78, and urges the sleeve 73 rearward.

[0107] The positioning member 75 is an annular member fixed to the outer peripheral surface of the anvil shaft 10C. The positioning member 75 is fixed at a position where it can face the rear end of the sleeve 73. The positioning member 75 positions the sleeve 73 at the blocking position. The sleeve 73, which is given an elastic force moving rearward by the coil spring 74, comes into contact with the positioning member 75, thereby being positioned at the blocking position.

[0108] The fan 12 is disposed forward of the stator 26 of the motor 6. The fan 12 generates an airflow for cooling the motor 6. The fan 12 is fixed to at least a portion of the rotor 27. The fan 12 is fixed to the front shaft portion 33F. The fan 12 is disposed between the rotor bearing 39F and the stator 26.

[0109] The fan 12 rotates due to the rotation of the rotor 27. As the rotor shaft portion 33 rotates, the fan 12 rotates together with the rotor shaft portion 33. As the fan 12 rotates, air from the external space of the housing 2 flows into the internal space of the housing 2 through the air intake port 19. 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 12 rotates, the air that has circulated through the internal space of the housing 2 is sent out radially outward from the fan 12. The air sent out by the fan 12 flows out through the exhaust port 20 within the housing 2 into the external space of the housing 2.

[0110] The battery attachment section 13 is disposed below the battery holding section 23. The battery attachment section 13 is connected to the battery pack 25. The battery pack 25 is attached to the battery attachment section 13. In the embodiment, there is one battery attachment section 13. One battery pack 25 is attached to the battery attachment section 13. The battery pack 25 is detachable from the battery attachment section 13. The battery pack 25 is attached to the battery attachment section 13 by being inserted into the battery attachment section 13 from the front of the battery holding section 23. The battery pack 25 is removed from the battery attachment section 13 by being removed forward from the battery attachment section 13. The battery pack 25 includes a secondary battery. In the embodiment, the battery pack 25 includes a rechargeable lithium-ion battery. When attached to the battery attachment section 13, the battery pack 25 can supply power to the power tool 1. The motor 6 is driven by the power supplied from the battery pack 25. The operation display unit 16 operates using power supplied from a battery pack 25 .

[0111] The rated voltage of the battery pack 25 is not particularly limited. For example, the rated voltage of the battery pack 25 is 18 V or higher. The rated voltage of the battery pack 25 may be 18 V, 36 V, or 72 V. Alternatively, the rated voltage of the battery pack 25 may be less than 18 V, such as 10.8 V or 14.4 V.

[0112] The trigger lever 14 is provided at the front of the grip portion 22. The trigger lever 14 is operated by an operator to start the motor 6. By operating the trigger lever 14, the motor 6 is switched between being driven and being stopped.

[0113] The forward / reverse switching lever 15 is provided on the upper part of the grip portion 22. The forward / reverse switching lever 15 is operated by an operator to switch the rotation direction of the motor 6. By operating the forward / reverse switching lever 15, 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 8 is switched.

[0114] The operation display unit 16 is provided on the battery holding unit 23. The operation display unit 16 is provided on the upper surface of the battery holding unit 23, further forward than the grip unit 22. The operation display unit 16 has a plurality of operation buttons 16A. The operation mode of the motor 6 is switched when the operator operates the operation buttons 16A. The operation display unit 16 may be located behind the grip unit 22, and may be provided on the rear surface of the battery holding unit 23, for example.

[0115] The mode changeover switch 17 is provided on the upper part of the trigger lever 14. The mode changeover switch 17 is operated by an operator to change the operation mode of the motor 6.

[0116] FIG. 7 is an exploded perspective view showing the light assembly 18 according to the embodiment. The light assembly 18 emits illumination light. The light assembly 18 illuminates the anvil 10 and the area around the anvil 10 with the illumination light. The light assembly 18 illuminates the area in front of the anvil 10 with the illumination light. The light assembly 18 also illuminates the tool accessory attached to the anvil 10 and the area around the tool accessory with the illumination light. In the embodiment, the light assembly 18 includes an annular light case 18A, a plurality of light-emitting elements 18B (see FIG. 5) held in the light case 18A, and a light cover 18C that covers the outer periphery of the light case 18A. The light case 18A is disposed around the second cylindrical portion 4B of the hammer case 4. An engagement rib 18D is formed on the inner circumferential surface of the light case 18A. The engagement rib 18D extends circumferentially on the inner circumferential surface of the light case 18A. A plurality of engagement ribs 18D are formed on the inner circumferential surface of the light case 18A. Engagement protrusions 4E that engage with the engagement ribs 18D are formed on the outer periphery of the second cylindrical portion 4B. The engagement protrusions 4E extend in the circumferential direction on the outer circumferential surface of the second cylindrical portion 4B. The number of engagement protrusions 4E provided is the same as the number of engagement ribs 18D.

[0117] When attaching the light assembly 18, the light assembly 18 is inserted from the front onto the outer periphery of the second cylindrical portion 4B with the rotational angle adjusted so that the engagement rib 18D and the engagement protrusion 4E are not in contact with each other, and then the light assembly 18 is rotated around the second cylindrical portion 4B so that the engagement rib 18D is positioned behind the engagement protrusion 4E. This causes the engagement rib 18D and the engagement protrusion 4E to engage in the front-rear direction, and the light assembly 18 is held in place by the hammer case 4. The light assembly 18 also has a retaining member 18E that prevents the light case 18A from slipping out forward from the second cylindrical portion 4B. The retaining member 18E is attached to the front side of the light case 18A in the second cylindrical portion 4B (see FIG. 5).

[0118] The hammer case cover 85 has an annular shape and has an opening 85A at the front. The hammer case cover 85 is attached to the front part of the hammer case 4 from the front side of the hammer case 4. The front part of the hammer case 4 protrudes forward from the opening 85A. The hammer case cover 85 is disposed behind the light assembly 18. The light assembly 18 also functions as a stopper that prevents the hammer case cover 85 from coming off forward from the hammer case 4.

[0119] [Rotor shaft and spindle support structure] FIG. 8 is a rear perspective view showing the bearing holding member 5 and spindle 8 according to the embodiment. FIG. 9 is an exploded front perspective view showing the support structure for the bearing and spindle 8 according to the embodiment. FIG. 10 is an exploded rear perspective view showing the support structure for the bearing and spindle 8 according to the embodiment. FIG. 11 is a vertical cross-sectional view showing the surrounding structure of the bearing holding member 5 according to the embodiment. FIG. 12 is an exploded front perspective view showing the bearing holding member 5 and hammer case 4 according to the embodiment. FIG. 13 is a cross-sectional view showing the bearing holding member 5 according to the embodiment from the front. Note that FIG. 13 shows a cross section perpendicular to the rotation axis AX.

[0120] In this embodiment, the spindle bearing 44 holds the rotor bearing 39F via the spindle 8. The spindle bearing 44 is held by a bearing holding member 5.

[0121] The bearing holding member 5 has an annular shape and includes a flat holding plate portion 55 extending in the radial direction. The bearing holding member 5 also includes a peripheral wall portion 56 that rises from the outer periphery of the holding plate portion 55 in the axial direction.

[0122] The holding plate 55 has an annular shape with a holding opening 55A formed in its center. The holding opening 55A has a circular shape and penetrates the holding plate 55 in the front-rear direction. The bearing holding member 5 holds the spindle bearing 44 within the holding opening 55A. The front surface of the holding plate 55 faces the spindle 8. The rear surface of the holding plate 55 faces the fan 12. A rib 58A, a first recess 58B, and a second recess 58C are formed on the front surface of the holding plate 55. The rib 58A, the first recess 58B, and the second recess 58C have an annular shape surrounding the holding opening 55A. The rib 58A protrudes forward from the front surface of the holding plate 55. The first recess 58B is located more inward than the rib 58A and recessed rearward from the front surface of the holding plate 55. The second recess 58C is located more inward than the first recess 58B and recessed rearward than the first recess 58B. The edge of the second recess 58C on the inner circumferential side is the edge of the holding opening 55A.

[0123] The peripheral wall portion 56 protrudes rearward from the outer periphery of the holding plate portion 55. The peripheral wall portion 56 extends along the outer periphery of the holding plate portion 55. The peripheral wall portion 56 is annular. A boss portion 5H is provided on the outer periphery of the peripheral wall portion 56. An insertion hole for inserting the screw member 4S is formed in the boss portion 5H.

[0124] 11, the bearing holding member 5 is fitted from the rear into the opening at the rear end of the first cylindrical portion 4A of the hammer case 4. A seal member 65 is provided between the outer peripheral surface of the bearing holding member 5 and the inner peripheral surface of the hammer case 4. The seal member 65 is an O-ring.

[0125] The spindle bearing 44 has an annular shape. The spindle bearing 44 is disposed on the inner peripheral surface of the retaining opening 55A. The spindle bearing 44 is retained in the retaining opening 55A. The inner peripheral surface of the spindle bearing 44 contacts the spindle 8. The spindle bearing 44 supports the outer peripheral surface of the spindle 8. The spindle bearing 44 includes a sliding bearing. The type of sliding bearing is not particularly limited, but in this embodiment, the spindle bearing 44 is a self-lubricating bearing (a so-called oil-less bearing). A sliding bearing has a simpler structure and higher rigidity than rolling bearings such as ball bearings. The spindle bearing 44 supports the spindle 8 in the radial direction. The spindle bearing 44 supports the spindle 8 in the axial direction. The spindle bearing 44 includes a radial bearing portion 44A and a thrust bearing portion 44B.

[0126] The radial bearing portion 44A radially supports the outer peripheral surface of the spindle 8. The radial bearing portion 44A is arranged on the inner peripheral surface of the holding opening 55A. The radial bearing portion 44A is annular. The outer peripheral surface of the radial bearing portion 44A contacts the inner surface of the holding opening 55A. The inner peripheral surface of the radial bearing portion 44A contacts the outer peripheral surface of the spindle 8. Specifically, the radial bearing portion 44A contacts the outer peripheral surface 81 of the holding portion 8C of the spindle 8. In this way, the spindle bearing 44 supports the outer peripheral surface 81 of the holding portion 8C of the spindle 8.

[0127] The thrust bearing portion 44B supports the spindle 8 in the axial direction. The thrust bearing portion 44B extends radially in a flange shape from the axial end face of the radial bearing portion 44A. The thrust bearing portion 44B extends radially outward from the front end face of the radial bearing portion 44A. The thrust bearing portion 44B fits along the front surface of the retaining plate portion 55. The rear surface of the thrust bearing portion 44B contacts the front surface of the retaining plate portion 55. The thrust bearing portion 44B functions as a positioning portion for the spindle bearing 44 in the front-to-rear direction. The front surface of the thrust bearing portion 44B faces the flange portion 8A of the spindle 8 in the axial direction. A sliding surface 44C is provided on the front surface of the thrust bearing portion 44B, which supports the rear surface of the flange portion 8A in the axial direction. Multiple sliding surfaces 44C are formed at equal intervals along the circumferential direction of the thrust bearing portion 44B. The sliding surfaces 44C are pad-shaped and extend in the circumferential direction on the front surface of the thrust bearing portion 44B. Adjacent sliding surfaces 44C are separated by grooves 44D. The grooves 44D function as reservoirs for the lubricant.

[0128] The spindle 8 is disposed on the inner peripheral side of the spindle bearing 44. The spindle 8 is rotatably supported by the spindle bearing 44.

[0129] The spindle 8 has a holding portion 8C that holds the rotor bearing 39F. The holding portion 8C has a cylindrical shape. The rotor bearing 39F and the rotor shaft portion 33 are arranged inside the holding portion 8C. The holding portion 8C protrudes rearward from the rear surface of the flange portion 8A. The central axis of the holding portion 8C coincides with the rotation axis of the spindle 8, i.e., the rotation axis AX of the motor 6.

[0130] The retaining portion 8C is arranged inside the retaining opening 55A of the bearing retaining member 5. The retaining portion 8C is arranged on the inner peripheral side of the spindle bearing 44. The retaining portion 8C has a circular outer peripheral surface 81. The outer peripheral surface 81 of the retaining portion 8C is a sliding surface that contacts the spindle bearing 44. The outer peripheral surface 81 of the retaining portion 8C contacts the inner peripheral surface of the radial bearing portion 44A. The rear surface of the flange portion 8A is a sliding surface that contacts the spindle bearing 44. The rear surface of the flange portion 8A can contact the sliding surface 44C of the thrust bearing portion 44B. The spindle bearing 44 supports the outer peripheral surface 81 of the retaining portion 8C in the radial direction and supports the rear surface of the flange portion 8A in the axial direction.

[0131] The spindle 8 is supported by a spindle bearing 44 at a holding portion 8C located at the rear, and is supported by the anvil 10 at a spindle recess 8E located at the front. The anvil 10 is supported by a bearing 46. The front portion of the spindle 8 is rotatably supported by the bearing 46 via the anvil 10.

[0132] The holding portion 8C has a circular inner peripheral surface 82. The holding portion 8C holds the rotor bearing 39F on the inner peripheral surface 82.

[0133] The rotor bearing 39F has an annular shape. The rotor bearing 39F is disposed on the inner peripheral surface of the spindle 8. The rotor bearing 39F is disposed on the inner peripheral surface 82 of the retaining portion 8C. The rotor bearing 39F supports the outer peripheral surface of the rotor shaft portion 33. The rotor bearing 39F includes a rolling bearing. The rotor bearing 39F has an inner ring 60A, an outer ring 60B, and rolling elements. The type of rolling bearing is not particularly limited, but in this embodiment, the rotor bearing 39F is a ball bearing. The rolling elements of the rotor bearing 39F are balls 60C. The rolling elements may be rollers or needles. The outer ring 60B of the rotor bearing 39F contacts the inner peripheral surface 82 of the retaining portion 8C. The inner ring 60A of the rotor bearing 39F contacts the outer peripheral surface of the rotor shaft portion 33. The rotor bearing 39F has an outer ring 60B fixed to the inner circumferential surface 82 of the retaining portion 8C, and an inner ring 60A that rotates together with the rotor shaft portion 33. The balls 60C of the rotor bearing 39F are disposed between the inner ring 60A and the outer ring 60B in the radial direction. The balls 60C of the rotor bearing 39F contact both the inner ring 60A and the outer ring 60B. The rotor bearing 39F has a plurality of balls 60C disposed in the circumferential direction.

[0134] As shown in FIG. 11 , the spindle 8 has an insertion hole 8G extending forward from the inner periphery of the retaining portion 8C. The insertion hole 8G extends axially through the center of the flange portion 8A and the shaft portion 8B. The interior of the retaining portion 8C is in communication with the insertion hole 8G. A pinion gear 41 at the front end of the rotor shaft portion 33 passes through the interior of the retaining portion 8C and is disposed in the insertion hole 8G. The pinion gear 41 meshes with a planetary gear 42 within the insertion hole 8G. The inner diameter of the retaining portion 8C is larger than the inner diameter of the insertion hole 8G. In other words, the inner periphery of the flange portion 8A is disposed radially inward of the inner periphery 82 of the retaining portion 8C. The rotor bearing 39F axially contacts the rear surface of the flange portion 8A inside the retaining portion 8C. The flange portion 8A functions as a positioning member for the rotor bearing 39F in the front-rear direction.

[0135] The rear portion of the pinion gear 41 and the non-gear portion 33A rearward of the pinion gear 41 of the rotor shaft portion 33 are disposed inside the retaining portion 8C. The inner ring 60A of the rotor bearing 39F contacts the outer peripheral surface of the non-gear portion 33A of the rotor shaft portion 33. The inner ring 60A of the rotor bearing 39F contacts the outer peripheral surface of the pinion gear 41. In other words, the rotor bearing 39F is disposed so as to straddle the non-gear portion 33A and the rear portion of the pinion gear 41. In the axial direction, the length L2 of the contact area of ​​the rotor bearing 39F with the pinion gear 41 is greater than the length L1 of the contact area with the non-gear portion 33A. This reduces the front-to-rear distance between the rotor bearing 39F and the planetary gear 42 compared to when the rotor bearing 39F is placed only in the non-gear portion 33A (placed rearward of the pinion gear 41), thereby shortening the overall length of the rotor shaft portion 33.

[0136] In this embodiment, the holding plate portion 55 of the bearing holding member 5, the holding portion 8C of the spindle 8, the spindle bearing 44, and the rotor bearing 39F are arranged in the same radial plane. That is, the spindle bearing 44 is arranged on the inner circumferential surface of the holding opening 55A of the holding plate portion 55, the holding portion 8C is arranged on the inner circumferential surface of the spindle bearing 44 (radial bearing portion 44A), and the rotor bearing 39F is arranged on the inner circumferential surface of the holding portion 8C. In this manner, the holding plate portion 55 of the bearing holding member 5, the holding portion 8C of the spindle 8, the spindle bearing 44, and the rotor bearing 39F are arranged in a nested manner in the same plane. As a result, the longitudinal dimension of the support structure for the spindle 8 and the rotor 27 is reduced compared to when the respective components are arranged offset in the longitudinal direction.

[0137] The bearing retaining member 5 holds the spindle bearing 44 in an open state, leaving both the end face of the spindle bearing 44 facing the spindle 8 (front face) and the end face of the spindle bearing 44 facing away from the spindle 8 (rear face) uncovered. The front face of the spindle bearing 44 is the sliding surface 44C of the thrust bearing portion 44B and faces the flange portion 8A without being covered by the bearing retaining member 5. As can be seen from FIG. 11 , the rear face of the spindle bearing 44 is the rear end face of the radial bearing portion 44A and faces the fan 12 without being covered by the bearing retaining member 5. Here, although not shown, if, for example, an annular recess recessed rearward from the front face is formed in the bearing retaining member 5 and the spindle bearing 44 is placed in the recess, the rear face of the spindle bearing 44 will be covered by the bearing retaining member 5. In this case, a space equivalent to the sum of the thickness of the spindle bearing 44 and the thickness of the bearing retaining member 5 covering the rear face of the spindle bearing 44 is required. In contrast to this, in the embodiment, the structure is such that neither the front side nor the rear side of the spindle bearing 44 is covered, so the space required in the front-rear direction to hold the spindle bearing 44 is reduced.

[0138] By providing the peripheral wall portion 56 on the outer periphery of the holding plate portion 55, the rigidity of the bearing holding member 5 in the front-rear direction is improved. In this embodiment, the holding plate portion 55 and the peripheral wall portion 56 of the bearing holding member 5 form a concave space recessed forward from the rear end surface. The fan 12 is disposed in the space surrounded by the holding plate portion 55 and the peripheral wall portion 56 of the bearing holding member 5. The fan 12 faces the holding plate portion 55 of the bearing holding member 5 in the front-rear direction. The radial outer side of the fan 12 is surrounded by the peripheral wall portion 56. The peripheral wall portion 56 has a plurality of ventilation holes 56A. The ventilation holes 56A penetrate the peripheral wall portion 56 in the radial direction. At least some of the plurality of ventilation holes 56A face the exhaust port 20 of the housing 2 in the radial direction. By providing the peripheral wall portion 56 and ensuring the rigidity of the bearing holding member 5, the fan 12 is disposed in the space surrounded by the holding plate portion 55 and the peripheral wall portion 56, thereby achieving space saving.

[0139] In the front-rear direction, the positions at which the vent hole 56A and the exhaust hole 20 are formed do not completely coincide with each other but are offset from each other. The exhaust hole 20 has a structure in which two through holes extending in the circumferential direction are lined up front and rear, and a portion separating the two through holes faces the vent hole 56A in the radial direction. Therefore, at least a portion of the vent hole 56A faces the portion of the rear case 2B other than the exhaust hole 20 in the radial direction. As a result, the vent hole 56A ensures an exhaust path, while the peripheral wall portion 56 prevents foreign matter from entering through the exhaust hole 20.

[0140] As shown in FIG. 12 , the holding plate 55 is formed with engagement recesses 55B recessed rearward from the front surface of the holding plate 55. A plurality of engagement recesses 55B are provided at intervals in the circumferential direction near the outer periphery of the holding plate 55. The engagement recesses 55B extend in an arc shape along the outer periphery of the holding plate 55. The engagement protrusions 43A of the internal gear 43 are disposed in the engagement recesses 55B. The engagement protrusions 43A protrude rearward from the rear end surface of the internal gear 43. A plurality of engagement protrusions 43A are provided at intervals in the circumferential direction of the internal gear 43, corresponding to the engagement recesses 55B of the holding plate 55. The internal gear 43 is positioned and fixed in the rotational direction by fitting the engagement protrusions 43A into the respective engagement recesses 55B.

[0141] As shown in FIG. 11 , the internal gear 43 is fitted into the first cylindrical portion 4A of the hammer case 4 from the rear. A stepped portion 4G in which the internal gear 43 is disposed is provided at the rear of the inner circumferential surface of the first cylindrical portion 4A. In the front-to-rear direction, the internal gear 43 is disposed between the wall at the front end of the stepped portion 4G and the bearing holding member 5. An O-ring 66 is disposed at the front end of the stepped portion 4G. The O-ring 66 seals the gap between the internal gear 43 and the hammer case 4. The O-ring 66 elastically deforms to eliminate backlash between the internal gear 43 and the hammer case 4 in the front-to-rear direction, and also functions as a damper to absorb impacts.

[0142] (Modified spindle bearing) FIG. 14 is a schematic longitudinal cross-sectional view showing a modified example of the spindle bearing 44. The spindle bearing 44 may be a rolling bearing instead of a plain bearing. In FIG. 14, the spindle bearing 244 is a ball bearing. The spindle bearing 244 has an inner ring 245A, an outer ring 245B, and rolling elements (balls 245C). The outer ring 245B of the spindle bearing 244 contacts the inner circumferential surface of the holding opening 55A of the bearing holding member 5. The inner ring 245A of the spindle bearing 244 contacts the outer circumferential surface 81 of the holding portion 8C of the spindle 8. The balls 245C are disposed radially between the inner ring 245A and the outer ring 245B. The balls 245C contact both the inner ring 245A and the outer ring 245B. The spindle bearing 244 has a flange portion 246 extending radially outward from the front end surface of the outer ring 245B. The flange portion 246 extends radially outward from the front end surface of the outer ring 245B. The flange portion 246 fits along the front surface of the holding plate portion 55. The rear surface of the flange portion 246 contacts the front surface of the holding plate portion 55. The flange portion 246 functions as a positioning portion for the spindle bearing 244 in the front-rear direction.

[0143] (Modified rotor bearing) FIG. 15 is a schematic longitudinal cross-sectional view showing a modified example of rotor bearing 39F. Rotor bearing 39F may be a plain bearing instead of a rolling bearing. In FIG. 15, rotor bearing 239F includes a plain bearing. The type of plain bearing is not particularly limited, but rotor bearing 239F is, for example, a self-lubricating bearing (a so-called oil-less bearing). The outer peripheral surface of rotor bearing 239F is fixed to inner peripheral surface 82 of holding portion 8C of spindle 8. Rotor bearing 239F supports the outer peripheral surface of rotor shaft portion 33. The inner peripheral surface of rotor bearing 239F is a sliding surface against rotor shaft portion 33.

[0144] (Modification of rotor bearing support portion) As described above, rotor bearing 39F is disposed so as to straddle non-gear portion 33A and the rear portion of pinion gear 41. In the example shown in FIG. 11, length L1 of the contact area of ​​rotor bearing 39F with non-gear portion 33A is greater than length L2 of the contact area of ​​rotor bearing 39F with pinion gear 41, but this is not limiting. FIG. 16 is a schematic vertical cross-sectional view showing a first modified example of a support portion of rotor bearing 39F. FIG. 17 is a schematic vertical cross-sectional view showing a second modified example of a support portion of rotor bearing 39F.

[0145] 16, the length L1 of the contact area of ​​rotor bearing 39F with non-gear portion 33A is equal to the length L2 of the contact area of ​​rotor bearing 39F with pinion gear 41. In FIG. 17, the length L1 of the contact area of ​​rotor bearing 39F with non-gear portion 33A is greater than the length L2 of the contact area of ​​rotor bearing 39F with pinion gear 41. Alternatively, rotor bearing 39F may be in contact only with non-gear portion 33A of rotor shaft 33 without contacting pinion gear 41. Rotor bearing 39F may be in contact only with pinion gear 41 of rotor shaft 33 without contacting non-gear portion 33A of rotor shaft 33.

[0146] [Housing and motor fixing structure] FIG. 18 is an exploded perspective view from the front showing the hammer case 4 and rear case 2B according to the embodiment. FIG. 19 is an exploded perspective view from the rear showing the hammer case 4 and rear case 2B according to the embodiment. FIG. 20 is a cross-sectional view showing a cross section passing through the screw member 4S connecting the hammer case 4 and the rear case 2B. Note that FIG. 20 is a cross-sectional view taken along line XX-XX in FIG. 13. FIG. 21 is a perspective view from the front showing the rear case 2B according to the embodiment. FIG. 22 is a perspective view from the front showing the motor 6 according to the embodiment. FIG. 23 is a perspective cross-sectional view showing a cross section passing through the stator core 28.

[0147] In this embodiment, at least a portion of the motor 6 is fixed to the motor housing 21 and the hammer case 4 by screw members 4S. In this embodiment, the motor housing 21 is provided in the rear case 2B. Therefore, at least a portion of the motor 6 is fixed to the rear case 2B and the hammer case 4.

[0148] The screw member 4S extends in the axial direction along the rotation axis AX. The screw member 4S reaches the hammer case 4 from behind the motor housing portion 21. The screw member 4S secures the motor housing portion 21 and the hammer case 4 to each other. A plurality of screw members 4S are arranged so as to surround the periphery of the motor 6 in the rotation direction. In this embodiment, four screw members 4S are provided, spaced apart in the rotation direction. The screw members 4S are arranged at positions corresponding to the four corners of the motor 6, namely the upper right, upper left, lower right, and lower left.

[0149] A screw insertion hole 21T (see FIG. 20) is formed on the outer periphery of the rear surface portion 21B of the motor accommodating portion 21. The motor accommodating portion 21 has a boss portion 21H in which the screw insertion hole 21T for inserting the screw member 4S is formed. Four boss portions 21H and four screw insertion holes 21T are formed at intervals in the rotational direction. The boss portion 21H is formed on the peripheral surface portion 21A of the motor accommodating portion 21 so as to cover the outside of the screw member 4S. The boss portion 21H has a semi-cylindrical shape like a cylinder divided in half.

[0150] Of the motor 6, the stator 26 is fixed together with the motor housing portion 21 and the hammer case 4 by the screw member 4S. The outer periphery of the stator 26 is sandwiched between the motor housing portion 21 and the hammer case 4 by the screw member 4S. In the embodiment, the stator core 28 is sandwiched between the motor housing portion 21 and the hammer case 4 by the screw member 4S. In addition, an insulator is sandwiched between the motor housing portion 21 and the hammer case 4 by the screw member 4S. Specifically, either the front insulator 29 or the rear insulator 30 is sandwiched between the motor housing portion 21 and the hammer case 4 by the screw member 4S. In the embodiment, the stator core 28 and the rear insulator 30 are fixed to the motor housing portion 21 and the hammer case 4 mutually by the screw member 4S. The front insulator 29 is not fixed by the screw member 4S.

[0151] The outer periphery of the stator core 28 and the outer periphery of the rear insulator 30 are disposed at approximately the same position in the radial direction. At least a portion of the outer periphery of the rear surface of the stator core 28 is covered by the outer periphery of the rear insulator 30. The outer periphery of the front insulator 29 is disposed at a position radially inward of the outer periphery of the stator core 28. At least a portion of the outer periphery of the front surface of the stator core 28 is disposed outward of the outer periphery of the front insulator 29 and is exposed from the front insulator 29.

[0152] The bearing holding member 5 has a boss portion 5H through which the screw member 4S is inserted. The hammer case 4 has a boss portion 4H with a threaded hole formed therein into which the screw member 4S is attached. The screw member 4S passes through a screw insertion hole 21T (see FIG. 20) of the motor housing portion 21 and a screw insertion hole 5T of the boss portion 5H of the bearing holding member 5, and engages with a screw hole 4T formed in the boss portion 4H of the hammer case 4. The bearing holding member 5 is fastened between the motor housing portion 21 and the hammer case 4 by the screw member 4S.

[0153] The boss portion 5H of the bearing retaining member 5 extends in the axial direction. The boss portion 5H has a cylindrical shape with a screw insertion hole 5T formed therein. As described above, the bearing retaining member 5 includes a retaining plate portion 55 that retains the rotor bearing 39F and a peripheral wall portion 56 that rises from the outer periphery of the retaining plate portion 55. The boss portion 5H is formed on the peripheral wall portion 56. The boss portion 5H protrudes rearward from the rear end surface of the peripheral wall portion 56 toward the stator core 28. Four boss portions 5H are provided, spaced apart in the rotational direction. The boss portions 5H are located at positions corresponding to the four corners of the bearing retaining member 5, namely, the upper right, upper left, lower right, and lower left. The axial dimension of the boss portion 5H is larger than the axial dimension of the peripheral wall portion 56. The bearing retaining member 5 has a rib 57 that protrudes from the boss portion 5H along the circumferential direction of the stator 26 (i.e., the circumferential direction of the peripheral wall portion 56). A pair of ribs 57 are formed so as to protrude outward from the boss portion 5H in the circumferential direction of the peripheral wall portion 56. The outer periphery of the stator 26 contacts the end face of the boss portion 5H and the end faces of the ribs 57. Specifically, the outer periphery of the front surface of the stator core 28, which is located outside the front insulator 29, contacts the boss portion 5H and the rear end faces of the ribs 57.

[0154] The hammer case 4 has four boss portions 4H spaced apart in the rotational direction. The boss portions 4H are disposed at positions corresponding to the four corners of the hammer case 4, namely the upper right, upper left, lower right, and lower left. The boss portions 4H are provided at the rear end portion of the hammer case 4. As a result, a screw hole 4T into which a screw member 4S is attached is formed at the rear end portion of the hammer case 4.

[0155] The inner diameters of the screw insertion holes 21T of the rear case 2B and the screw insertion holes 5T of the boss portions 5H are larger than the outer diameters of the threaded portions of the screw members 4S. That is, the screw insertion holes 21T of the rear case 2B and the screw insertion holes 5T of the boss portions 5H do not mesh with the threaded portions of the screw members 4S. The rear end surface of the hammer case 4 contacts the front end surface of the bearing holding member 5 in the front-rear direction. The rear end surface of the bearing holding member 5 contacts the front surface of the stator core 28. That is, the rear end surfaces of the boss portions 5H and the ribs 57 contact the outer periphery of the front surface of the stator core 28. The stator core 28 contacts the rear end surfaces of the boss portions 5H and the ribs 57 at contact portions CP in FIG. 20 . The outer periphery of the rear surface of the stator core 28 contacts the outer periphery of the front surface of the rear insulator 30. The outer periphery of the rear surface of the rear insulator 30 contacts the inner surface of the motor accommodating portion 21 in the axial direction. The motor accommodating portion 21 has a support surface 21D that comes into contact with the rear insulator 30. The fastening force of the screw members 4S causes the stator core 28, the rear insulator 30, and the bearing holding member 5 to be sandwiched between the rear case 2B and the hammer case 4. The outer periphery of the stator 26 and the bearing holding member 5 are fixed by being sandwiched between the motor accommodating portion 21 and the hammer case 4.

[0156] As a result, the rear case 2B, the stator 26, and the bearing holding member 5 are fixed to the hammer case 4. In this manner, in the embodiment, the rear case 2B, the motor 6, the hammer case 4, and the bearing holding member 5 are fixed together by the screw members 4S extending axially from the rear of the rear case 2B. The outer periphery of the stator 26 and the bearing holding member 5 are fixed by being sandwiched between the motor housing portion 21 and the hammer case 4. The outer periphery of the stator 26 (the stator core 28 and the rear insulator 30) is sandwiched between the motor housing portion 21 and the end faces of the boss portions 5H and the ribs 57.

[0157] The boss portion 5H also functions as a spacer that forms a space between the holding plate portion 55 and the motor 6. The motor 6 and the holding plate portion 55 are separated by a distance corresponding to the length of the boss portion 5H, forming a space surrounded by the motor 6 and the bearing holding member 5. The fan 12 that rotates together with the rotor 27 is disposed in the space surrounded by the motor 6, the holding plate portion 55, and the peripheral wall portion 56. Furthermore, at least a portion of the front insulator 29 is disposed in the space surrounded by the motor 6, the holding plate portion 55, and the peripheral wall portion 56.

[0158] Furthermore, the screw members 4S pass radially outward of the outer peripheral surface of the stator core 28. There is no contact between the screw members 4S and the outer peripheral surface of the stator core 28. There is no contact between the screw members 4S and the inner surface of the boss portion 21H of the motor accommodating portion 21. During assembly by inserting the screw members 4S into the screw insertion holes 21T of the motor accommodating portion 21, the shanks of the screw members 4S can be easily inserted without getting caught on the stator core 28 or the boss portion 21H.

[0159] [Housing split structure] Fig. 24 is an exploded perspective view showing the housing 2 according to the embodiment. Fig. 25 is a perspective view showing the left housing 2L according to the embodiment. Fig. 26 is a perspective view showing the right housing 2R according to the embodiment. Fig. 27 is an exploded perspective view showing the connection portion between the left housing 2L and the right housing 2R. Fig. 28 is an exploded perspective view showing the rear case 2B according to the embodiment and the left and right housings 2L and 2R.

[0160] As described above, the housing 2 includes a left housing 2L and a right housing 2R that are divided in the left-right direction intersecting with the rotation axis AX. The grip portion 22 and the battery holding portion 23 are divided into left and right portions and provided on one side of the left housing 2L and the right housing 2R. The left housing 2L has a left side portion of the grip portion 22 and a left side portion of the battery holding portion 23. The right housing 2R has a right side portion of the grip portion 22 and a right side portion of the battery holding portion 23.

[0161] Specifically, the grip portion 22 includes a left grip portion 22L and a right grip portion 22R that are divided in the left-right direction intersecting with the rotation axis AX. The battery holding portion 23 includes a left battery holding portion 23L formed integrally with the left grip portion 22L and a right battery holding portion 23R formed integrally with the right grip portion 22R.

[0162] The left housing 2L and the right housing 2R are fixed to each other. The left housing 2L and the right housing 2R are connected by screws 2S extending in the left-right direction in the grip portion 22 and the battery holding portion 23. The screws 2S are inserted from the right side of the right housing 2R through screw insertion holes in the right housing 2R and into screw holes in the left housing 2L. The screw holes are holes with female threads that mesh with the male threads. For example, the screws 2S are tapping screws, and by fastening the screws 2S into pilot holes formed in the left housing 2L, the female threads are formed in the pilot holes by the screws 2S. The screw insertion holes and screw holes are provided in two locations near the top end of the grip portion 22, two locations in the middle of the grip portion 22 in the up-down direction, and two locations in the battery holding portion 23.

[0163] A cylindrical case holder 24 that covers the periphery of the hammer case 4 so that the anvil (output portion) 10 protrudes forward is integrally formed with either the left housing 2L or the right housing 2R. That is, the case holder 24 is integrally formed with either the left grip portion 22L or the right grip portion 22R. In the embodiment, the case holder 24 is formed in the left housing 2L (left grip portion 22L). The case holder 24 may also be formed in the right housing 2R (right grip portion 22R).

[0164] The case holder 24 is not a left-right divided structure, but is a cylindrical shape formed integrally with the left housing 2L as a whole. The case holder 24 is not formed on the right housing 2R. In other words, while the left housing 2L (left grip portion 22L) and the right housing 2R (right grip portion 22R) have a left-right divided structure, the case holder 24 has a non-divided structure and is formed on either the left or right side. The case holder 24 is connected to the upper end of the grip portion 22. The lower end of the case holder 24 is continuous with the upper end of the left grip portion 22L of the grip portion 22.

[0165] Therefore, the left housing 2L has a case holding portion 24, a left grip portion 22L of the grip portion 22, and a left battery holding portion 23L of the battery holding portion 23. The case holding portion 24, the left grip portion 22L of the grip portion 22, and the left battery holding portion 23L of the battery holding portion 23 are integrally formed with the left housing 2L. The right housing 2R has a right grip portion 22R of the grip portion 22 and a right battery holding portion 23R of the battery holding portion 23. The right grip portion 22R of the grip portion 22 and the right battery holding portion 23R of the battery holding portion 23 are integrally formed with the right housing 2R.

[0166] The trigger lever 14 is provided at the front of the grip portion 22. The forward / reverse rotation switch lever 15 is provided at the top of the grip portion 22. By dividing the grip portion 22 into left and right parts, the assembly of the trigger lever 14 and the forward / reverse rotation switch lever 15 and the wiring can be easily performed.

[0167] The rear case 2B is disposed so as to straddle the left housing 2L and the right housing 2R. The rear case 2B is connected to the left housing 2L and the right housing 2R with screws 93L and 93R, respectively. The peripheral surface 21A of the rear case 2B is not a perfect cylinder but has an arc shape with a notched bottom. The left end of the arc-shaped peripheral surface 21A connects to the upper end of the left housing 2L, and the right end of the arc-shaped peripheral surface 21A connects to the upper end of the right housing 2R. Two bosses 90L and 90R are provided on the lower part of the rear surface 21B of the rear case 2B, through which the screws 93L and 93R are inserted in the front-rear direction. One of the bosses 90L is located on the left side of the lower part of the rear surface 21B and faces the boss 91L of the left housing 2L in the front-rear direction. The boss 91L is provided on the upper end of the left grip portion 22L. The other boss portion 90R is located on the right side of the lower part of the rear surface portion 21B and faces the boss portion 91R of the right housing 2R in the front-rear direction. The boss portion 91R is provided at the upper end of the right grip portion 22R. Screw holes are formed in the boss portions 91L and 91R. Screws 93L and 93R pass through the boss portions 90L and 90R, respectively, and are attached to the boss portions 91L and 91R.

[0168] In this way, the rear case 2B is connected to the left housing 2L by the screw 93L at the upper end of the left portion of the grip portion 22. The rear case 2B is connected to the right housing 2R by the screw 93R at the upper end of the right portion of the grip portion 22. As a result, the motor accommodating portion 21 formed in the rear case 2B is connected to the upper end of the left grip portion 22L and the upper end of the right grip portion 22R by the screws 93L and 93R, respectively.

[0169] The case holding portion 24 has a front opening 24A and a rear opening 24B. The case holding portion 24 holds the outer periphery of the hammer case 4 when the hammer case 4 is inserted from the rear opening 24B toward the front opening 24A. Recesses 24C that engage with protrusions 4C provided on the outer periphery of the hammer case 4 are formed on the inner circumferential surface of the case holding portion 24. The protrusions 4C are formed at multiple locations along the circumferential direction of the hammer case 4. The recesses 24C of the case holding portion 24 are formed at multiple locations along the circumferential direction of the case holding portion 24 to correspond to the protrusions 4C. When the protrusions 4C engage with the recesses 24C, the hammer case 4 and the case holding portion 24 engage with each other in the rotational direction, and misalignment of the hammer case 4 in the rotational direction is suppressed.

[0170] As described above, the rear case 2B is connected to the rear part of the hammer case 4 by screws (screw members 4S) extending in the axial direction along the rotation axis AX. The rear case 2B is fixed to the hammer case 4 together with the bearing holding member 5 by the four screw members 4S.

[0171] The hammer case 4 is fixed to the housing 2 via a connecting member 95. The hammer case 4 is connected to the left grip portion 22L and the right grip portion 22R via the connecting member 95 extending in the left-right direction. In this embodiment, the connecting member 95 is a cylindrical pin member. The connecting member 95 is made of metal.

[0172] A connection boss 4D is provided on the outer periphery of the hammer case 4, through which a connection member 95 extending in the left-right direction is inserted. One connection boss 4D is provided at the front and one at the rear of the underside of the hammer case 4. The connection boss 4D has a left-right through-hole through which the connection member 95 is inserted. The connection member 95 inserted into the connection boss 4D has one end and the other end protruding to the left and right sides of the connection boss 4D, respectively. The connection boss 4D and the connection member 95 are disposed at the front and rear of the hammer case 4, respectively.

[0173] One end and the other end of the connecting member 95 inserted into the connection boss portion 4D are connected to the left grip portion 22L and the right grip portion 22R, respectively. The left housing 2L has a left support portion 96L that supports one end of the connecting member 95 inserted into the connection boss portion 4D. The left support portion 96L is a cylindrical portion that receives the connecting member 95. Two left support portions 96L are provided on the left housing 2L to correspond to the two connecting members 95. The left support portion 96L is provided on the upper part of the left grip portion 22L. The right housing 2R has a right support portion 96R that supports the other end of the connecting member 95 inserted into the connection boss portion 4D. The right support portion 96R is a cylindrical portion that receives the connecting member 95. Two right support portions 96R are provided on the right housing 2R to correspond to the two connecting members 95. The right support portion 96R is provided on the upper part of the right grip portion 22R. Therefore, the left housing 2L and the right housing 2R are connected to the hammer case 4 via a connecting member 95 extending in the left-right direction.

[0174] In this way, the outer periphery of the hammer case 4 is held by the case holding portion 24 that surrounds the periphery of the hammer case 4. The rear end of the hammer case 4 is held by the rear case 2B, which is connected by four screw members 4S. The lower part of the hammer case 4 is held by the left housing 2L and the right housing 2R, which are connected by two connecting members 95. The case holding portion 24 prevents the hammer case 4 from shifting radially and rotationally relative to the housing 2. The two connecting members 95 prevent the hammer case 4 from shifting forward and backward relative to the housing 2. The two connecting members 95 and the connecting boss portion 4D prevent the hammer case 4 from shifting rotationally relative to the housing 2.

[0175] Because the case holder 24 does not have a split structure, there is no need to arrange left-right screws between the hammer case 4 and the motor 6. Because each component, such as the motor 6, bearing holder 5, reduction mechanism 7, and impact mechanism 9, is arranged along the axial direction, arranging left-right screws requires widening the axial spacing between the components to ensure space for the screws to pass through. As a result, if space for the screws is provided, the axial dimension of the installation space for each component increases. In the embodiment, there is no need to arrange left-right screws between the hammer case 4 and the motor 6, and therefore the axial dimension of the installation space for each component is reduced accordingly.

[0176] During assembly, components such as the motor 6 and fan 12 are stacked axially inside the rear case 2B, the rotation mechanism 3 is housed in the hammer case 4, the bearing holder 5 is fitted to the rear of the hammer case 4, and the rear case 2B and hammer case 4 are joined together with the screw member 4S. The subassembly of the rear case 2B and hammer case 4 is inserted into the case holder 24 from the rear. This completes the assembly of the upper part of the power tool 1. If the case holder 24 has a left-right split structure, the case holder 24 is assembled laterally between the rear case 2B and the hammer case 4, where the components are arranged axially. This changes the direction of the assembly work by 90 degrees. In this embodiment, the assembly work can be performed consistently in the same direction (axial direction), improving the ease of assembly.

[0177] [Power tool dimensions and specifications] Next, an example of dimensions and specifications of each part of the power tool 1 will be described. Fig. 29 is a vertical cross-sectional view for explaining the dimensions of each part of the power tool 1 according to an embodiment. Fig. 29 shows a vertical cross-section of the upper part of the power tool 1, similar to Fig. 4.

[0178] As shown in Fig. 29, the power tool 1 according to this embodiment has a total head length L11. The total head length L11 is the distance in the front-to-rear direction between the tip of the anvil 10 and the rear surface of the upper part of the power tool 1 (the rear surface of the rear case 2B). The total head length L11 is, for example, 115 mm or less, preferably 110 mm or less, and more preferably 105 mm or less. In the example shown in this embodiment, the total head length L11 is 102.9 mm.

[0179] The maximum tightening torque of the power tool 1 is, for example, 225 N·m or more, preferably 230 N·m or more, and more preferably 235 N·m or more. The maximum tightening torque is the torque when a fastening member is tightened, and generally refers to the torque measured by the retightening torque method for a fastening member after tightening. The retightening torque method applies torque to a fastening member after tightening and measures the torque when the fastening member begins to turn again. Note that this method does not involve loosening a nut or bolt to measure the torque. In the example shown in the embodiment, the maximum tightening torque is 230 N·m.

[0180] The power tool 1 has a motor-to-bearing distance L12. The motor-to-bearing distance L12 is the distance in the front-to-rear direction between the rear surface of the rotor shaft portion 33 and the front surface of the rotor bearing 39F. The motor-to-bearing distance L12 is, for example, 35 mm or less, preferably 30 mm or less, and more preferably 25 mm or less. In the example shown in the embodiment, the motor-to-bearing distance L12 is 27.95 mm.

[0181] The power tool 1 has a motor thickness (motor stack thickness) L13. The motor thickness L13 is the distance in the front-to-rear direction between the front and rear surfaces of the motor 6 excluding the rotor shaft portion 33. The motor thickness L13 is, for example, 22 mm or less, preferably 20 mm or less, and more preferably 18 mm or less. In the example shown in the embodiment, the motor thickness L13 is 17.6 mm.

[0182] The stator lamination thickness L21 of the motor 6 is, for example, 10 mm or less, preferably 8 mm or less, and more preferably 6 mm or less. The stator lamination thickness L21 is the distance (thickness) between the front and rear surfaces of the stator core 28. In the example shown in the embodiment, the stator lamination thickness L21 is 5.0 mm.

[0183] The rotor length L22 of the motor 6 is, for example, 12 mm or less, preferably 10 mm or less, and more preferably 8 mm or less. The rotor length L22 is the length between the front and rear surfaces of the rotor core portion 32. In the example shown in the embodiment, the rotor length L22 is 5.5 mm.

[0184] The rotor core outer diameter D11 of the motor 6 is, for example, 22 mm or more, preferably 24 mm or more, and more preferably 26 mm or more. The rotor core outer diameter D11 is the outer diameter dimension of the rotor core portion 32. In the example shown in the embodiment, the rotor core outer diameter D11 is 27.5 mm.

[0185] The stator outer diameter D12 of the motor 6 is, for example, 45 mm or more, preferably 47 mm or more, and more preferably 49 mm or more. The stator outer diameter D12 is the outer diameter dimension of the stator 26, and in this embodiment, is equal to the outer dimension of the stator core 28. In the example shown in this embodiment, the stator outer diameter D12 is 50 mm.

[0186] The core inner diameter of the motor 6 is, for example, 39 mm or more, preferably 41 mm or more, and more preferably 43 mm or more. The core inner diameter is the inner diameter of the core portion of the stator core 28 excluding the teeth. In the example shown in the embodiment, the core inner diameter is 43 mm.

[0187] The inner diameter of the teeth of the motor 6 is, for example, 22 mm or more, preferably 25 mm or more, and more preferably 28 mm or more. The inner diameter of the teeth is the inner diameter of the teeth portion of the stator core 28. In the example shown in the embodiment, the inner diameter of the teeth is 28.5 mm.

[0188] In the example shown in the embodiment, the maximum rotation speed of the output shaft of the power tool 1 is 3700 rpm. In the example shown in the embodiment, the total length of the spindle 8 is 45.65 mm.

[0189] In the power tool 1, a distance L14 from the rear surface of the upper part of the power tool 1 (the rear surface of the rear case 2B) to the front surface of the internal gear 43 is, for example, 42 mm or less, preferably 40 mm or less, and more preferably 38 mm or less. In the example shown in the embodiment, the distance L14 is 35.1 mm.

[0190] In the power tool 1, the distance L15 from the rear surface of the upper part of the power tool 1 (the rear surface of the rear case 2B) to the rear end of the hammer case 4 is, for example, 35 mm or less, preferably 30 mm or less, and more preferably 25 mm or less. In the example shown in the embodiment, the distance L15 is 25.1 mm.

[0191] The gear outer diameter of the reduction gear mechanism 7 is, for example, 47.5 mm or more, preferably 47.75 mm or more, and more preferably 48 mm or more. The gear outer diameter is the outer diameter dimension of the internal gear 43. In the example shown in the embodiment, the gear outer diameter is 47.5 mm. In addition, in the example shown in the embodiment, the gear ratio of the reduction gear mechanism 7 is 9.

[0192] The moment of inertia of the hammer 47 of the power tool 1 is, for example, 34 kg / mm 2 or more, preferably 35 kg / mm 2 More preferably, 36 kg / mm 2 In the example shown in the embodiment, the moment of inertia of the hammer 47 is 34.1 kg / mm 2 In the example shown in the embodiment, the outer diameter of the hammer 47 is 43 mm.

[0193] The hammer stroke of the power tool 1 is, for example, 9 mm or more, preferably 9.5 mm or more, and more preferably 10 mm or more. The hammer stroke is the distance in the front-to-rear direction between the forward limit position and the backward limit position of the hammer 47. In the example shown in the embodiment, the hammer stroke is 9.11 mm.

[0194] The mounting load of the coil spring 49 of the power tool 1 is, for example, 115 N or less, preferably 110 N or less, and more preferably 105 N or less. The mounting load is the magnitude of the elastic force of the coil spring 49 when the hammer 47 is at the forward limit position. Note that the mounting load is not the load required for assembling the coil spring 49. In the example shown in the embodiment, the mounting load is 120 N.

[0195] The full-stroke load of the coil spring 49 of the power tool 1 is, for example, 480 N or less, preferably 470 N or less, and more preferably 460 N or less. The full-stroke load is the magnitude of the elastic force of the coil spring 49 when the hammer 47 is at the most retracted position. In the example shown in the embodiment, the full-stroke load is 448 N.

[0196] The spring constant of the coil spring 49 is, for example, 36 N / mm or less, preferably 35 N / mm or less, and more preferably 34 N / mm or less. If the spring constant varies within the range of the hammer stroke, it is set to the minimum value within the range of the hammer stroke. In the example shown in the embodiment, the spring constant of the coil spring 49 is 36 N / mm.

[0197] In the example shown in the embodiment, the maximum number of impacts of the power tool 1 is 4600 (times / min).

[0198] As shown in FIG. 20 , in this embodiment, the outer periphery of the stator core 28 overlaps with the head of the screw 4S in the front-rear direction. The outer periphery of the stator core 28 and the head of the screw 4S overlap within a range of length L16 in the radial direction of the screw 4S. That is, length L16 is the distance between the outer periphery of the stator core 28 and the outer periphery of the head of the screw 4S in the radial direction of the screw 4S. Length L16 is, for example, 0 mm or more, preferably 0.5 mm or more, and more preferably 1 mm or more. Note that in this specification, overlap is also considered to occur when length L16 = 0, i.e., when the outer periphery of the stator core 28 and the outer periphery of the head of the screw 4S contact each other at a single point as viewed in the front-rear direction. In the example shown in this embodiment, length L16 is 1.4 mm.

[0199] Thus, the embodiments disclose an impact driver having a total head length L11 of 115 mm or less and a maximum tightening torque of 225 N·m or more. The embodiments also disclose an impact driver equipped with a flat rotor 27 having a length (rotor length L22) of 10 mm or less and a diameter (rotor core outer diameter D11) of 25 mm or more. The embodiments also disclose an impact driver equipped with a flat annular stator 26 having a length (stator stacking thickness L21) of 10 mm or less and a diameter (stator outer diameter D12) of 45 mm or more.

[0200] [Power tool operation] Next, the operation of the power tool 1 will be described.

[0201] When performing a screw tightening operation on a workpiece, a tool bit (driver bit) to be used for the screw tightening operation is inserted into the tool hole 10A of the anvil 10. The tool bit inserted into the tool hole 10A is held by the tool holding mechanism 11. After the tool bit is attached to the anvil 10, the operator grips the grip portion 22 with, for example, the right hand and pulls the trigger lever 14. When the trigger lever 14 is pulled, power is supplied from the battery pack 25 to the motor 6, the motor 6 is started, and simultaneously, the light assembly 18 is illuminated. When the motor 6 is started, the rotor shaft portion 33 of the rotor 27 rotates. When the rotor shaft portion 33 rotates, the rotational force of the rotor shaft portion 33 is transmitted to the planetary gear 42 via the pinion gear 41. The planetary gear 42, engaged with the internal teeth of the internal gear 43, revolves around the pinion gear 41 while rotating on its axis. The planetary gear 42 is rotatably supported by the spindle 8 via a pin 42P. The revolution of the planetary gear 42 causes the spindle 8 to rotate at a rotation speed lower than the rotation speed of the rotor shaft portion 33.

[0202] When the spindle 8 rotates while the hammer 47 and the anvil protrusion 10D are in contact with each other, the anvil 10 rotates together with the hammer 47 and the spindle 8. As the anvil 10 rotates, the screw tightening operation progresses. The rotational force of the spindle 8 is transmitted to the hammer 47 via the ball 48. When the spindle 8 and the hammer 47 are rotating together, the ball 48 is positioned at the front of the spindle groove 8D.

[0203] As the screw tightening operation progresses, if a load torque equal to or greater than a predetermined value acts on the anvil 10 from the screw, the rotation of the anvil 10 and the hammer 47 stops. Because the spindle 8 continues to rotate by the motor 6, if the spindle 8 continues to rotate while the rotation of the hammer 47 is stopped, the hammer 47 moves rearward relative to the spindle 8. In other words, the ball 48 moves rearward along the spindle groove 8D, and the hammer 47 moves rearward as the ball 48 moves.

[0204] As the hammer 47 moves rearward relative to the spindle 8, contact between the hammer 47 and the anvil protrusion 10D is released. After the rearward-moving hammer 47 is released from contact with the anvil protrusion 10D, the forward biasing force of the coil spring 49 stops the rearward movement of the hammer 47. The stopped hammer 47 moves forward while rotating due to the forward biasing force of the coil spring 49. When the hammer 47 moves forward relative to the spindle 8, the ball 48 moves forward along the spindle groove 8D.

[0205] As the hammer 47 moves forward while rotating, the anvil 10 is struck in the rotational direction by the hammer 47. This causes the anvil 10 to rotate about the rotation axis AX with high torque, thereby tightening the screw into the workpiece with high torque.

[0206] [effect] As described above, in the embodiment, the power tool 1 includes the motor 6, the motor housing 21 that houses the motor 6, the rotation mechanism 3 that is arranged forward of the motor 6 and includes the anvil (output unit) 10 that rotates based on the rotational force of the motor 6, the hammer case (rotation mechanism case) 4 that is arranged forward of the motor housing 21 and houses at least a part of the rotation mechanism 3, and the screw member 4S that reaches the hammer case 4 from behind the motor housing 21 and secures the motor housing 21 and the hammer case 4 to each other. The motor 6 is secured together with the motor housing 21 and the hammer case 4 by the screw member 4S.

[0207] In the above configuration, the motor 6 in the motor housing 21 is fixed together with the motor housing 21 and the hammer case 4 by the front-rear screw member 4S that secures the motor housing 21 and the hammer case 4 to each other. This eliminates the need to provide space for arranging left-right screws between the motor 6 and the rotation mechanism 3. Furthermore, compared to using separate screws to secure the motor housing 21 that houses the motor 6 to the hammer case 4 and to secure the motor 6 inside the motor housing 21, the space required for arranging the screws can be reduced. As a result, the overall length of the power tool 1 can be prevented from increasing due to the screws that secure the housing 2. Furthermore, the number of parts and the weight of the power tool 1 can be reduced.

[0208] In the embodiment, the motor 6 includes a rotor 27 that rotates about a rotation axis AX, and a stator 26 that is disposed around the rotor 27. The outer periphery of the stator 26 is clamped between the motor housing portion 21 and the hammer case (rotation mechanism case) 4 by a screw member 4S.

[0209] In the above configuration, the motor housing portion 21, the hammer case 4, and the stator 26 can be fixed together by the same screw member 4S.

[0210] In the embodiment, the stator 26 includes a stator core 28, an insulator made of an electrical insulating material, and a coil disposed on the stator 26 via the insulator. The stator core 28 is clamped between the motor housing portion 21 and the hammer case (rotation mechanism case) 4 by screw members 4S.

[0211] In the above configuration, the stator core 28 of the stator 26 can be fixed together with the motor housing portion 21 and the hammer case 4 by the screw members 4S. The stator core 28 is made of a laminate of steel plates or the like and has high rigidity, so that the stator 26 can be firmly fixed by clamping the stator core 28.

[0212] In this embodiment, the stator 26 includes a stator core 28, an insulator made of an electrical insulating material, and a coil 31 disposed on the stator 26 via the insulator. The insulator is clamped between the motor housing portion 21 and the hammer case (rotation mechanism case) 4 by screw members 4S.

[0213] In the above configuration, the insulator of the stator 26 can be fixed together with the motor housing 21 and the hammer case 4 by the screw members 4S. For example, unlike when a separate member for clamping with the screw members 4S is provided on the stator 26, the number of parts does not increase, and the number of parts and weight of the power tool 1 can be reduced.

[0214] In the embodiment, the insulators include a front insulator 29 provided in the front portion of the stator core 28 and a rear insulator 30 provided in the rear portion of the stator core 28. Either the front insulator 29 or the rear insulator 30 is clamped between the motor accommodating portion 21 and the hammer case (rotation mechanism case) 4 by a screw member 4S.

[0215] In the above configuration, one of the front insulator 29 and the rear insulator 30 can be clamped by the screw member 4S, while the other is not clamped. Compared to the case where both the front insulator 29 and the rear insulator 30 are clamped, the influence of dimensional tolerances is reduced.

[0216] In the embodiment, the power tool 1 further includes a bearing holding member 5 having a rotor bearing 39F that rotatably supports the rotor 27. The stator 26, together with the bearing holding member 5, is fixed between the motor housing 21 and the hammer case (rotation mechanism case) 4 by screw members 4S.

[0217] In the above configuration, not only the stator 26 but also the bearing holding member 5 can be fixed with the same screw member 4S as the motor accommodating portion 21 and the hammer case 4. This makes it possible to more effectively reduce the number of parts and the weight of the power tool 1.

[0218] In the embodiment, the outer periphery of the stator 26 and the bearing holding member 5 are fixed by being sandwiched between the motor housing portion 21 and the hammer case (rotation mechanism case) 4.

[0219] In the above configuration, the outer periphery of the stator 26 and the bearing holding member 5 are sandwiched and fixed between the motor accommodating portion 21 and the hammer case 4, and the rotor 27 can be rotationally supported by the rotor bearing 39F of the bearing holding member 5.

[0220] In this embodiment, the bearing holding member 5 has a boss portion 5H extending in the axial direction, through which the screw member 4S is inserted. The outer periphery of the stator 26 is sandwiched between the motor accommodating portion 21 and the end face of the boss portion 5H.

[0221] In the above configuration, by providing the boss portion 5H on the bearing holding member 5, the axial force of the screw member 4S can be effectively applied to the bearing holding member 5 to fix it. Furthermore, the boss portion 5H of the bearing holding member 5 can be used as a contact portion for fixing the stator 26.

[0222] In this embodiment, the bearing retaining member 5 has ribs 57 that protrude from the boss portion 5H in the circumferential direction of the stator 26. The outer periphery of the stator 26 contacts the end face of the boss portion 5H and the end face of the ribs 57.

[0223] In the above configuration, the rigidity of the boss portion 5H can be increased by providing the ribs 57 on the boss portion 5H. Furthermore, the contact area between the bearing retaining member 5 and the stator 26 can be increased by bringing the end faces of the boss portion 5H and the ribs 57 into contact with the outer periphery of the stator 26. As a result, the stability of fixation by the screw members 4S can be improved.

[0224] In the embodiment, the bearing retaining member 5 includes a retaining plate 55 that retains the rotor bearing 39F, and a peripheral wall 56 that rises from the outer periphery of the retaining plate 55 and has a boss 5H formed thereon. The power tool 1 further includes a fan 12 that rotates together with the rotor 27 in a space surrounded by the motor 6, the retaining plate 55, and the peripheral wall 56.

[0225] In the above configuration, the end face of the boss portion 5H provided on the peripheral wall portion 56 comes into contact with the stator 26, and therefore the boss portion 5H can function as a spacer that provides a gap between the motor 6 (the rotor 27 and the stator 26) and the holding plate portion 55 of the bearing holding member 5. By arranging the fan 12 in the space thus formed, a structure that can efficiently cool the motor 6 can be realized without providing a separate spacer member for adjusting the position of each component.

[0226] In the embodiment, the screw member 4S passes radially outward from the outer circumferential surface of the stator core .

[0227] In the above configuration, the screw member 4S and the stator 26 can be kept out of contact with each other without providing any special structure between them. When assembling the power tool 1 or operating the power tool 1, the stator core 28 is prevented from coming into contact with the screw member 4S, which can cause wear or peeling of the steel plate.

[0228] In this embodiment, the bearing retaining member 5 is made of metal.

[0229] With the above configuration, high mechanical strength and high rigidity can be easily obtained. The bearing holding member 5 may be made of resin, and when a resin bearing holding member 5 is used, it can be easily formed into a shape suitable for being fixed between the motor housing portion 21 and the hammer case 4 by the axial force of the screw member 4S.

[0230] In this embodiment, a plurality of screw members 4S are arranged so as to surround the periphery of the motor 6 in the rotation direction.

[0231] In the above configuration, the motor 6 can be firmly fixed without providing a separate screw dedicated to fixing the motor 6 inside the motor accommodating portion 21.

[0232] In this embodiment, the hammer case (rotation mechanism case) 4 is made of metal. A screw hole into which a screw member 4S is attached is formed at the rear end of the hammer case 4.

[0233] In the above configuration, a metal case with high mechanical strength and rigidity can be used as the hammer case 4, so the motor accommodating section 21 and the motor 6 can be stably fixed. Also, for example, there is no need to embed a metal nut member or the like only in the screw hole portion, and the screw hole can be formed directly in the hammer case 4.

[0234] In the embodiment, the power tool 1 is an impact tool. The power tool 1 includes: a motor 6; a motor housing 21 that houses the motor 6; a rotation mechanism 3 that includes a hammer 47 that is disposed forward of the motor 6 and rotated about a rotation axis AX by the motor 6; and an anvil 10 that is struck in the rotational direction by the hammer 47; a hammer case (rotation mechanism case) 4 that is disposed forward of the motor housing 21 and houses at least a portion of the rotation mechanism 3; and a screw member 4S that extends from the rear of the motor housing 21 to the hammer case 4 and secures the motor housing 21 and the hammer case 4 to each other. At least a portion of the motor 6 is secured together with the motor housing 21 and the hammer case 4 by the screw member 4S.

[0235] In the above configuration, the motor 6 in the motor housing 21 is fixed together with the motor housing 21 and the hammer case 4 by the front-rear screw member 4S that secures the motor housing 21 and the hammer case 4 to each other. This eliminates the need to provide space for arranging screws in the left-right direction between the motor 6 and the rotation mechanism 3. Furthermore, compared to the case where separate screws are used to secure the motor housing 21 that houses the motor 6 to the hammer case 4 and to secure the motor 6 inside the motor housing 21, the space required for arranging the screws can be reduced. As a result, it is possible to prevent the overall length of the impact tool from increasing due to the screws that secure the housing 2. Furthermore, the number of parts and the weight of the impact tool can be reduced.

[0236] [Another embodiment] In the above-described embodiment, an engaging protrusion 43A protruding rearward is provided on the rear end surface of the internal gear 43 (see FIG. 12), and the engaging protrusion 43A is fitted into the engaging recess 55B of the bearing holding member 5, thereby positioning and fixing the internal gear 43 in the rotational direction. The internal gear 43 may also be positioned and fixed in the rotational direction by engaging with the hammer case 4 instead of the bearing holding member 5. FIG. 30 is a vertical cross-sectional view showing the upper part of a power tool 1 according to another embodiment. FIG. 31 is an exploded perspective view from the rear showing a bearing holding member, internal gear, and hammer case according to another embodiment.

[0237] In the example shown in Figures 30 and 31, the internal gear 43 is fitted into the first cylindrical portion 4A of the hammer case 4 from the rear. A stepped portion 4G in which the internal gear 43 is disposed is provided at the rear of the inner circumferential surface of the first cylindrical portion 4A. The stepped portion 4G is a step recessed radially outward on the inner circumferential surface of the first cylindrical portion 4A. As shown in Figure 31, the internal gear 43 has an engaging protrusion 43B that protrudes forward from the front end face of the internal gear 43. An engaging recess 4F into which the engaging protrusion 43B fits is formed in the stepped portion 4G of the hammer case 4. A plurality of engaging protrusions 43B are formed at intervals in the circumferential direction of the internal gear 43. A plurality of engaging recesses 4F are formed at intervals in the circumferential direction of the hammer case 4. Each engaging protrusion 43B and each engaging recess 4F are formed at the same position in the circumferential direction and face each other in the front-to-rear direction. The internal gear 43 is positioned and fixed in the rotational direction by fitting the engaging protrusions 43B into the respective engaging recesses 4F. As shown in Figure 30, the internal gear 43 is disposed between the wall at the front end of the stepped portion 4G and the bearing holder 5 in the front-to-rear direction. An O-ring 67 is provided at the rear end of the internal gear 43. The O-ring 67 seals the gap between the internal gear 43 and the hammer case 4. The O-ring 67 elastically deforms to eliminate backlash between the internal gear 43 and the bearing holder 5 in the front-to-rear direction, and also functions as a damper to absorb impacts.

[0238] In the above-described embodiment, the power tool 1 is an impact driver. The power tool 1 may be an impact wrench. FIG. 32 is a rear perspective view of a power tool 1A according to another embodiment. The power tool 1A in FIG. 32 is an impact wrench, which is a type of impact tool. The anvil (output portion) 210 of the power tool 1A has an anvil shaft portion 210A to which a tool bit is attached. The anvil shaft portion 210A is disposed at the front of the anvil 210. The anvil shaft portion 210A protrudes forward beyond the cylindrical case holder 224. The housing 202 has a motor accommodating portion 221, a grip portion 222, and a cylindrical case holder 224. The housing 202 is divided into a left housing 202L and a right housing 202R. The cylindrical case holder 224, the motor accommodating portion 221, and a left portion of the grip portion 222 (left grip portion 222L) are integrally formed with the left housing 202L. The right housing 202R is integrally formed with a right portion of the grip portion 222 (right grip portion 222R). The left housing 202L and the right housing 202R are fixed at multiple locations with screws 2S in the left-right direction. The right housing 202R is fixed to the motor accommodating portion 221 with screws 222S provided on the front part of the upper surface of the right grip portion 222R. In the example of FIG. 32, the battery holding portion 223 is provided in a battery housing 225 that is separate from the housing 202. The battery housing 225 is fixed to the housing 202 with screws.

[0239] The hammer case (rotation mechanism case) 204 is inserted into the case holding portion 224 from the front. The case holding portion 224 has a cylindrical shape with an open front portion and a rear portion connected to the motor accommodating portion 221. The motor accommodating portion 221 accommodates the motor 6. A screw member 204S extending in the axial direction is inserted from the rear of the motor accommodating portion 221. The screw member 204S reaches the hammer case 204. The screw member 204S engages with a threaded hole formed in a boss portion 204H of the hammer case 204. The motor 6 is fixed together with the motor accommodating portion 221 and the hammer case 204 by the screw member 204S. The power tool 1A is a large impact wrench and has a detachable side handle 400.

[0240] In the above-described embodiment, the power tool 1 is an impact tool. However, the power tool 1 may be a power tool other than an impact tool. FIG. 33 is a rear perspective view of a power tool 1B according to another embodiment. The power tool 1B in FIG. 33 is a driver drill, which is a type of drilling machine. The power tool 1B includes a motor, a motor housing 321 that houses the motor, a rotation mechanism that is disposed forward of the motor and includes an output unit 310 that rotates based on the rotational force of the motor, and a rotation mechanism case 304 that is disposed forward of the motor housing 321 and houses at least a portion of the rotation mechanism.

[0241] The output unit 310 is disposed forward of the motor. The output unit 310 rotates due to the rotational force of the motor. The output unit 310 rotates with the tool bit attached. The rotation mechanism includes a speed reduction mechanism and a vibration mechanism. At least a portion of the speed reduction mechanism is housed in the rotation mechanism case 304. At least a portion of the vibration mechanism is housed in the rotation mechanism case 304. The speed reduction mechanism reduces the rotation of the motor (rotor shaft) and rotates the output unit 310 at a lower rotational speed than the rotor shaft. The vibration mechanism vibrates the output unit 310 in the axial direction. The vibration mechanism includes multiple cams that rotate based on the rotational force of the motor and converts the rotation of the cams into reciprocating motion in the axial direction. The vibration mechanism vibrates the output unit 310 in the axial direction based on the reciprocating motion of the cams in the axial direction.

[0242] The housing 302 has a motor accommodating portion 321, a grip portion 322, a battery holding portion 323, and a cylindrical case holding portion 324. The housing 302 is divided into a left housing 302L and a right housing 302R. The left housing 302L is integrally formed with the cylindrical case holding portion 324, the motor accommodating portion 321, a left portion of the grip portion 322 (left grip portion 322L), and a left portion of the battery holding portion 323 (left battery holding portion 323L). The right housing 302R is integrally formed with a right portion of the grip portion 322 (right grip portion 322R) and a right portion of the battery holding portion 323 (right battery holding portion 323R). The left housing 302L and the right housing 302R are fixed at multiple locations with screws in the left-right direction.

[0243] The case holding portion 324 has a cylindrical shape, is open at the front, and is connected at the rear to the motor accommodating portion 321. The motor accommodating portion 321 has a cylindrical shape, and is covered at the rear by a rear cover 325. The rotation mechanism case 304 is inserted into the case holding portion 324 from the front. The motor accommodating portion 321 accommodates the motor. A screw member 304S extending in the axial direction is inserted from the rear of the motor accommodating portion 321. The screw member 304S passes through a screw insertion hole formed in the rear cover 325, passes through the motor accommodating portion 321, and reaches the rotation mechanism case 304. The screw member 304S engages with a screw hole formed in a boss portion 304H of the rotation mechanism case 304. The motor accommodated in the motor accommodating portion 321 is fixed together with the motor accommodating portion 321 and the rotation mechanism case 304 by the screw member 304S.

[0244] In the above-described embodiment, the power source of the power tool 1 does not have to be the battery pack 25, but may be a commercial power source (AC power source). The commercial power source inputs a voltage of 18 V or more to the motor 6. [Explanation of symbols]

[0245] 1...power tool, 1A...power tool, 1B...power tool, 2...housing, 2B...rear case, 2L...left housing, 2R...right housing, 2S...screw, 3...rotation mechanism, 4...hammer case (rotation mechanism case), 4A...first cylindrical portion, 4B...second cylindrical portion, 4C...projection, 4D...connection boss portion, 4E...engaging convex portion, 4F...engaging concave portion, 4G...step portion, 4H...boss portion, 4S...screw member, 4T...screw hole, 5...bearing holding member, 5H...boss portion, 5T...screw insertion hole, 6...motor, 7...reduction mechanism, 8...spindle, 8A...flange portion, 8B...shaft portion, 8C...holding portion, 8D...spindle groove, 8E... Spindle recess, 8G...insertion hole, 9...impact mechanism, 10...anvil (output part), 10A...tool hole, 10B...anvil convex part, 10C...anvil shaft part, 10D...anvil protrusion part, 11...tool holding mechanism, 12...fan, 13...battery mounting part, 14...trigger lever, 15...forward / reverse switching lever, 16...operation display part, 16A...operation button, 17...mode switching switch, 18...light assembly, 18A...light case, 18B...light emitting element, 18C...light cover, 18D...engagement rib, 18E...prevention member, 19...air intake, 20...exhaust port, 21...motor housing part, 21A... Circumferential surface portion, 21B...rear surface portion, 21D...support surface, 21H...boss portion, 21T...screw insertion hole, 22...grip portion, 22L...left grip portion, 22R...right grip portion, 23...battery holding portion, 23L...left battery holding portion, 23R...right battery holding portion, 24...case holding portion, 24A...front opening, 24B...rear opening, 24C...recess, 25...battery pack, 26...stator, 27...rotor, 28...stator core, 29...front insulator, 30...rear insulator, 31...coil, 32...rotor core portion, 33...rotor shaft portion, 33A...non-gear portion, 33F...front shaft portion, 33R...rear shaft portion, 37...sensor board, 37S...screw, 39F...rotor bearing, 39R...rotor bearing, 41...pinion gear, 42...planetary gear, 42P...pin, 43...internal gear, 43A...engaging protrusion, 44...spindle bearing, 44A...radial bearing portion, 44B...thrust bearing portion, 44C...sliding surface, 44D...groove, 45...O-ring, 46...bearing, 47...hammer, 47A...hole, 47B...hammer groove, 47C...recess, 47D...hammer body, 47E...hammer protrusion, 48...ball, 49...coil spring, 50...washer, 51...ball,55...retaining plate portion, 55A...retaining opening, 55B...engagement recess, 56...peripheral wall portion, 56A...ventilation hole, 57...rib, 58A...rib, 58B...first recess, 58C...second recess, 60A...inner ring, 60B...outer ring, 60C...ball, 65...sealing member, 66...O-ring, 67...O-ring, 71...ball, 72...leaf spring, 73...sleeve, 74...coil spring, 75...positioning member, 76...support recess, 77...ring spring, 78...washer, 81...outer peripheral surface, 82...inner peripheral surface, 8 5...Hammer case cover, 85A...Opening, 90L...Boss portion, 90R...Boss portion, 91L...Boss portion, 91R...Boss portion, 95...Connecting member, 96L...Left side support portion, 96R...Right side support portion, 202...Housing, 202L...Left housing, 202R...Right housing, 204...Hammer case (rotation mechanism case), 204H...Boss portion, 204S...Screw member, 210...Anvil (output portion), 210A...Anvil shaft portion, 221...Motor accommodating portion, 222...Grip portion, 222L...Left grip portion, 222R...right grip portion, 223...battery holding portion, 224...case holding portion, 225...battery housing, 239F...rotor bearing, 244...spindle bearing, 245A...inner ring, 245B...outer ring, 245C...ball, 246...flange portion, 302...housing, 302L...left housing, 302R...right housing, 304...rotation mechanism case, 304H...boss portion, 304S...screw member, 310...output portion, 321...motor accommodating portion, 322...grip portion, 322L...left grip Grip portion, 322R...right grip portion, 323...battery holding portion, 323R...right battery holding portion, 323L...left battery holding portion, 324...case holding portion, 325...rear cover, 400...side handle, AX...rotating shaft, CP...contact portion, D11...rotor core outer diameter, D12...stator outer diameter, L1...length, L2...length, L11...total head length, L12...distance between motor bearings, L13...motor thickness, L14...distance, L15...distance, L16...length, L21...stator stack thickness, L22...rotor length.

Claims

1. A motor; a motor housing portion that houses the motor; a rotation mechanism section including an output section that is disposed forward of the motor and that rotates based on the rotational force of the motor; a rotation mechanism case disposed in front of the motor housing portion and housing at least a portion of the rotation mechanism portion; a screw member that reaches the rotation mechanism case from behind the motor housing portion and fixes the motor housing portion and the rotation mechanism case to each other, the motor is fixed together with the motor housing and the rotation mechanism case by the screw member; Power tools.

2. the motor includes a rotor that rotates around a rotation axis and a stator that is disposed around the rotor; an outer circumferential portion of the stator is clamped between the motor accommodating portion and the rotation mechanism case by the screw member; The power tool according to claim 1 .

3. the stator includes a stator core, an insulator made of an electrical insulating material, and a coil disposed in the stator via the insulator, the stator core is clamped between the motor accommodating portion and the rotation mechanism case by the screw member; The power tool according to claim 2.

4. the stator includes a stator core, an insulator made of an electrical insulating material, and a coil disposed in the stator via the insulator, the insulator is clamped between the motor accommodating portion and the rotation mechanism case by the screw member; The power tool according to claim 2.

5. the insulator includes a front insulator provided in a front portion of the stator core and a rear insulator provided in a rear portion of the stator core, one of the front insulator and the rear insulator is clamped between the motor accommodating portion and the rotation mechanism case by the screw member; The power tool according to claim 4.

6. a bearing holding member having a rotor bearing that rotatably supports the rotor; the stator, together with the bearing holding member, is fixed between the motor accommodating portion and the rotation mechanism case by the screw member; The power tool according to claim 2.

7. an outer circumferential portion of the stator and the bearing holding member are fixed by being sandwiched between the motor accommodating portion and the rotation mechanism case; The power tool according to claim 6.

8. the bearing retaining member has a boss portion extending in the axial direction and through which the screw member is inserted, an outer circumferential portion of the stator is sandwiched between the motor accommodating portion and an end face of the boss portion; The power tool according to claim 7.

9. the bearing retaining member has a rib that protrudes from the boss portion along the circumferential direction of the stator, an outer circumferential portion of the stator contacts an end face of the boss portion and an end face of the rib; The power tool according to claim 8.

10. the bearing holding member includes a holding plate portion that holds the rotor bearing, and a peripheral wall portion that rises from an outer periphery of the holding plate portion and on which the boss portion is formed, a fan that rotates together with the rotor and is disposed in a space surrounded by the motor, the holding plate portion, and the peripheral wall portion; The power tool according to claim 8.

11. The screw member passes radially outward from the outer circumferential surface of the stator core. The power tool according to claim 3.

12. The bearing retaining member is made of metal or resin. The power tool according to claim 8.

13. a plurality of the screw members are arranged so as to surround the periphery of the motor in the rotation direction; The power tool according to claim 1 .

14. the rotation mechanism case is made of metal, A screw hole into which the screw member is attached is formed at the rear end of the rotation mechanism case. The power tool according to claim 1 .

15. A motor; a motor housing portion that houses the motor; a rotation mechanism including a hammer disposed forward of the motor and rotated around a rotation axis by the motor, and an anvil struck in the rotation direction by the hammer; a rotation mechanism case disposed in front of the motor housing portion and housing at least a portion of the rotation mechanism portion; a screw member that reaches the rotation mechanism case from behind the motor housing portion and fixes the motor housing portion and the rotation mechanism case to each other, At least a portion of the motor is fixed together with the motor housing and the rotation mechanism case by the screw member. Impact tool.

Images