Impact tools

Abstract

To suppress shortening of a service life of an impact tool.SOLUTION: An impact tool includes: a motor; a spindle which has at least a part arranged in front of the motor and is rotated by the motor; a hammer which is arranged around the spindle; an anvil which has at least a part arranged in front of the spindle and is struck by the hammer in a rotation direction; an internal space which is formed in the spindle so as to extend forward from an opening provided on a rear end face of the spindle and includes a first space in which lubricating oil is stored; a first support port which is provided on an outer peripheral surface of the spindle and supplies the lubricating oil from the first space toward a space between the spindle and the hammer; and a lid which is inserted from the opening and is arranged in a second space of the internal space connected to a rear end of the first space.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] In the technical field related to impact tools, an impact tool such as that disclosed in Patent Document 1 is known. The impact tool disclosed in Patent Document 1 includes a spindle and a hammer disposed around the spindle. Lubricating oil is accommodated in the internal space of the spindle. The lubricating oil is supplied from the internal space of the spindle to between the spindle and the hammer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-037560 Summary of the Invention [Problem to be solved by the invention]

[0004] If lubricating oil leaks from the internal space of the spindle, the amount of lubricating oil supplied between the spindle and the hammer will decrease, which may result in severe wear or seizure of at least one of the spindle and the hammer, shortening the life of the impact tool.

[0005] The technology disclosed in this specification aims to prevent the life of an impact tool from being shortened. [Means for solving the problem]

[0006] The present specification discloses an impact tool. The impact tool may include a motor, a spindle, a hammer, an anvil, and a lid. At least a portion of the spindle may be disposed forward of the motor. The spindle may be rotated by the motor. The hammer may be disposed around the spindle. At least a portion of the anvil may be disposed forward of the spindle. The anvil may be struck by the hammer in the rotational direction. An internal space may be formed inside the spindle. The internal space may be formed to extend forward from an opening provided in a rear end surface of the spindle. The internal space may include a first space that contains lubricating oil and a second space in which the lid is disposed. The second space may be disposed rearward of the first space. A rear end of the first space and a front end of the second space may be connected. The opening may be provided at the rear end of the second space. The lid may be inserted into the second space through the opening. A first supply port may be provided in an outer peripheral surface of the spindle to supply lubricating oil from the first space between the spindle and the hammer. [Effects of the Invention]

[0007] According to the technology disclosed in this specification, shortening of the life of the impact tool is suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front perspective view showing an impact tool according to an embodiment. [Figure 2] FIG. 2 is a side view showing an upper portion of the impact tool according to the embodiment. [Figure 3] FIG. 3 is a vertical cross-sectional view showing an upper portion of the impact tool according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing the upper part of the impact tool according to the embodiment. [Figure 5] FIG. 5 is an exploded perspective view from the front showing a part of the impact tool according to the embodiment. [Figure 6] FIG. 6 is an exploded perspective view showing a part of the impact tool according to the embodiment, seen from the rear. [Figure 7] FIG. 7 is a cross-sectional view schematically showing a spindle and anvil according to a modified example. [Figure 8] FIG. 8 is a cross-sectional view schematically showing a spindle according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] In one or more embodiments, the impact tool may include a motor, a spindle, a hammer, an anvil, and a lid. At least a portion of the spindle may be disposed forward of the motor. The spindle may be rotated by the motor. The hammer may be disposed around the spindle. At least a portion of the anvil may be disposed forward of the spindle. The anvil may be struck by the hammer in the rotational direction. An internal space may be formed inside the spindle. The internal space may be formed to extend forward from an opening provided in a rear end surface of the spindle. The internal space may include a first space that contains lubricating oil and a second space in which the lid is disposed. The second space may be disposed rearward of the first space. A rear end of the first space and a front end of the second space may be connected. The opening may be provided at the rear end of the second space. The lid may be inserted into the second space through the opening. A first supply port may be provided in an outer peripheral surface of the spindle to supply lubricating oil from the first space between the spindle and the hammer.

[0010] In the above configuration, the lid is disposed in the second space behind the first space containing the lubricating oil. This prevents the lubricating oil contained in the first space from leaking through the opening. This prevents the amount of lubricating oil supplied between the spindle and the hammer from the first supply port from becoming too small. This prevents wear or seizure of the spindle and the hammer, and prevents a shortened lifespan of the impact tool.

[0011] In one or more embodiments, the lid may be made of felt.

[0012] The above configuration prevents a decrease in workability when inserting the lid into the second space through the opening. Because the felt is deformable, an impact tool assembler can insert the lid into the second space with good workability by crushing the felt while inserting it into the second space. Furthermore, by inserting the felt, which has an outer diameter larger than the inner diameter of the second space, into the second space while being crushed, the outer surface of the felt comes into close contact with the inner surface of the second space. Therefore, the sealing performance between the outer surface of the felt and the inner surface of the second space is improved, effectively preventing leakage of the lubricating oil contained in the first space through the opening.

[0013] The lid may be made of metal, synthetic resin, or rubber.

[0014] In one or more embodiments, the inner diameter of the first space may be smaller than the inner diameter of the second space.

[0015] In the above configuration, a lid having an outer diameter larger than the inner diameter of the first space is placed in the second space.

[0016] In one or more embodiments, a step may be provided at the boundary between the rear end of the first space and the front end of the second space, and the lid may be supported by the step.

[0017] In the above configuration, the step portion prevents the lid inserted into the second space from entering the first space through the opening. The step portion positions the lid in the front-rear direction.

[0018] The inner diameter of the first space may be larger than the inner diameter of the second space.

[0019] In one or more embodiments, the hammer may have a body portion and an inner cylindrical portion protruding rearward from the body portion and having an inner circumferential surface that contacts the outer circumferential surface of the spindle. The first supply port may supply lubricating oil between the outer circumferential surface of the spindle and the inner circumferential surface of the inner cylindrical portion of the hammer.

[0020] In the above configuration, lubricating oil is supplied from the first space between the outer surface of the spindle and the inner surface of the inner cylindrical portion of the hammer, thereby suppressing wear or seizure between the outer surface of the hammer of the spindle and the inner surface of the inner cylindrical portion of the hammer.

[0021] In one or more embodiments, a plurality of first supply ports may be provided in the circumferential direction.

[0022] In the above configuration, a plurality of first supply ports are provided in the circumferential direction, so that lubricating oil is evenly supplied between the outer circumferential surface of the spindle and the inner circumferential surface of the inner cylindrical portion of the hammer.

[0023] In one or more embodiments, the impact tool may include a first groove provided on the inner circumferential surface of the inner cylindrical portion of the hammer, the first groove containing lubricant.

[0024] In the above configuration, lubricating oil is supplied from the first groove between the outer peripheral surface of the spindle and the inner peripheral surface of the inner cylindrical portion of the hammer, thereby suppressing wear or seizure between the outer peripheral surface of the spindle and the inner peripheral surface of the inner cylindrical portion of the hammer.

[0025] In one or more embodiments, the first groove may be located forward of the first supply port.

[0026] In the above configuration, the first supply port and the first groove are positioned at different positions in the front-rear direction, so that lubricating oil is evenly supplied between the outer circumferential surface of the spindle and the inner circumferential surface of the inner cylindrical portion of the hammer.

[0027] The first groove may be provided behind the first supply port, or may be provided so as to face the first supply port.

[0028] In one or more embodiments, the impact tool may include a ball disposed between the spindle and the hammer, and a second supply port located on the outer surface of the spindle forward of the first supply port and supplying lubricating oil from the first space to the ball.

[0029] In the above configuration, lubricating oil is supplied to the balls from the first space, which reduces wear on the balls and also reduces wear on the inner surfaces of the spindle groove and hammer groove that come into contact with the balls.

[0030] In one or more embodiments, a plurality of second supply ports may be provided in the circumferential direction.

[0031] In the above configuration, a plurality of second supply ports are provided in the circumferential direction, so that the lubricating oil is supplied evenly to the balls.

[0032] In one or more embodiments, the first supply port and the second supply port may be disposed at different positions in the circumferential direction.

[0033] In the above configuration, the lubricating oil is evenly supplied from the first space to each of the spindle, the hammer, and the ball.

[0034] In one or more embodiments, the impact tool may include a third supply port provided on the front end surface of the spindle for supplying lubricating oil from the first space to between the spindle and the anvil.

[0035] In the above configuration, the lubricating oil is supplied from the first space between the spindle and the anvil, thereby suppressing wear of the spindle and the anvil.

[0036] In one or more embodiments, the spindle may have a spindle shaft portion and a spindle protrusion or a spindle recess provided at a front end of the spindle shaft portion. The anvil may be provided at a rear end surface of the anvil and may have an anvil recess in which the spindle protrusion is disposed or an anvil protrusion disposed in the spindle recess. The hammer may be disposed around the spindle shaft portion. The third supply port may be provided on the front end surface of the spindle protrusion or on the inner surface of the spindle recess.

[0037] In the above configuration, lubricating oil is supplied from the first space between the surface of the spindle convex portion and the inner surface of the anvil concave portion, or between the inner surface of the spindle concave portion and the surface of the anvil convex portion, thereby suppressing wear between the surface of the spindle convex portion and the inner surface of the anvil concave portion, or between the inner surface of the spindle concave portion and the surface of the anvil convex portion.

[0038] In one or more embodiments, the impact tool may include a second groove provided on the outer circumferential surface of the spindle protrusion or the inner circumferential surface of the spindle recess, and configured to accommodate lubricant.

[0039] In the above configuration, lubricating oil is supplied from the second groove between the surface of the spindle convex portion and the inner surface of the anvil concave portion, thereby suppressing wear between the surface of the spindle convex portion and the inner surface of the anvil concave portion, or wear between the inner surface of the spindle concave portion and the surface of the anvil convex portion.

[0040] [Embodiment] The 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 impact tool 1. The impact tool 1 has a motor 6 as a power source.

[0041] 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.

[0042] 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.

[0043] <Impact tool> FIG. 1 is a front perspective view showing an impact tool 1 according to an embodiment. FIG. 2 is a side view showing an upper part of the impact tool 1 according to an embodiment. FIG. 3 is a vertical cross-sectional view showing an upper part of the impact tool 1 according to an embodiment. FIG. 4 is a horizontal cross-sectional view showing an upper part of the impact tool 1 according to an embodiment. FIG. 5 is an exploded front perspective view showing a part of the impact tool 1 according to an embodiment. FIG. 6 is an exploded rear perspective view showing a part of the impact tool 1 according to an embodiment.

[0044] In the embodiment, the impact tool 1 is an impact driver, which is a type of screw tightening tool, and includes a housing 2, a rear cover 3, a hammer case 4, a bearing box 24, a hammer case cover 51, a bumper 52, a motor 6, a speed reduction mechanism 7, a spindle 8, a striking mechanism 9, an anvil 10, a tool holding mechanism 11, a fan 12, a battery mounting portion 13, a trigger lever 14, a forward / reverse rotation switching lever 15, an operation display portion 16, 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 with a plurality of screws 2S. The housing 2 is made up of a pair of split housing halves.

[0046] The housing 2 has a motor accommodating portion 21, a grip portion 22, and a battery holding portion 23.

[0047] The motor accommodating portion 21 accommodates the motor 6. The motor accommodating portion 21 accommodates at least a portion of the hammer case 4. The motor accommodating portion 21 is cylindrical.

[0048] The grip portion 22 is held by an operator and extends downward from the motor housing portion 21. The trigger lever 14 is provided on the upper portion of the grip portion 22.

[0049] The battery holding portion 23 holds the battery pack 25 via the battery attachment portion 13. The battery holding portion 23 is connected to the lower end of the grip portion 22. The external dimensions of the battery holding portion 23 are larger than the external dimensions of the grip portion 22 in both the front-rear and left-right directions.

[0050] The rear cover 3 is arranged to cover the opening at the rear end of the motor accommodating section 21. The rear cover 3 is arranged behind the motor accommodating section 21. The rear cover 3 accommodates at least a portion of the fan 12. The fan 12 is arranged inside the rear cover 3. The rear cover 3 holds the rear rotor bearing 37. The rear cover 3 is made of synthetic resin. The rear cover 3 is fixed to the rear end of the motor accommodating section 21 with two screws 3S.

[0051] The motor accommodating section 21 has an air intake port 19. The rear cover 3 has an air exhaust port 20. Air from the external space of the housing 2 flows into the internal space of the housing 2 through the air intake port 19. Air from the internal space of the housing 2 flows out to the external space of the housing 2 through the air exhaust port 20.

[0052] The hammer case 4 accommodates at least a portion of the reduction mechanism 7, the spindle 8, the striking mechanism 9, and at least a portion of the anvil 10. 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 includes a large cylinder portion 4A, a small cylinder portion 4B, and a connecting portion 4C. The small cylinder portion 4B is positioned forward of the large cylinder portion 4A. The front end of the large cylinder portion 4A and the rear end of the small cylinder portion 4B are connected via the connecting portion 4C. The connecting portion 4C is annular. The outer diameter of the large cylinder portion 4A is larger than the outer diameter of the small cylinder portion 4B. The inner diameter of the large cylinder portion 4A is larger than the inner diameter of the small cylinder portion 4B.

[0053] The bearing box 24 accommodates at least a portion of the reduction gear mechanism 7. The bearing box 24 holds the front rotor bearing 38 and the spindle bearing 44. The bearing box 24 is made of metal. The bearing box 24 is fixed to the rear of the hammer case 4. The bearing box 24 has a rear annular portion 24A and a front annular portion 24B. The front annular portion 24B is disposed forward of the rear annular portion 24A. The front end of the rear annular portion 24A and the rear end of the front annular portion 24B are connected via a connecting portion 24C. The connecting portion 24C is annular. The outer diameter of the rear annular portion 24A is smaller than the outer diameter of the front annular portion 24B. The inner diameter of the rear annular portion 24A is smaller than the inner diameter of the front annular portion 24B. The bearing box 24 and the hammer case 4 may be fixed by a threaded portion or by fitting (loose fitting). For example, a screw thread may be formed on the outer periphery of the front annular portion 24B, and a screw groove may be formed on the inner periphery of the large cylindrical portion 4A. The bearing box 24 and the hammer case 4 may be fixed together by engaging the screw threads of the front annular portion 24B with the screw grooves of the large cylindrical portion 4A. The bearing box 24 and the hammer case 4 may be fixed together by fitting the front annular portion 24B into the large cylindrical portion 4A. The front rotor bearing 38 is disposed radially inside the rear annular portion 24A. The spindle bearing 44 is disposed radially inside the connecting portion 24C.

[0054] The hammer case 4 is sandwiched between the left housing 2L and the right housing 2R. The rear part of the hammer case 4 is housed in the motor housing portion 21. The hammer case 4 is connected to the front part of the motor housing portion 21. The bearing box 24 is fixed to both the motor housing portion 21 and the hammer case 4.

[0055] The hammer case cover 51 protects the hammer case 4. The hammer case cover 51 prevents the hammer case 4 from coming into contact with objects around the hammer case 4. The hammer case cover 51 is disposed so as to cover the outer peripheral surface of the large cylinder portion 4A. The hammer case cover 51 may be omitted.

[0056] The bumper 52 protects the hammer case 4. The bumper 52 prevents the hammer case 4 from coming into contact with an object around the hammer case 4. The bumper 52 reduces the impact when the hammer case 4 comes into contact with an object. The bumper 52 is disposed around the small cylindrical portion 4B.

[0057] The motor 6 is a power source for the impact 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 21. At least a portion of the rotor 27 is disposed inside the stator 26. The rotor 27 rotates relative to the stator 26. The rotor 27 rotates about a rotation axis AX extending in the front-rear direction.

[0058] The stator 26 includes a stator core 28 , a rear insulator 29 , a front insulator 30 , and a coil 31 .

[0059] The stator core 28 includes a plurality of stacked steel plates. The steel plates are made of a metal whose main component is iron. The stator core 28 is cylindrical. The stator core 28 is disposed radially outward of the rotor 27. The stator core 28 has a plurality of teeth that support the coils 31.

[0060] The rear insulator 29 and the front insulator 30 are each an electrical insulating member made of synthetic resin. The rear insulator 29 and the front insulator 30 each electrically insulate the stator core 28 from the coil 31. The rear insulator 29 is fixed to the rear part of the stator core 28. The front insulator 30 is fixed to the front part of the stator core 28. The rear insulator 29 is arranged so as to cover part of the surface of the teeth. The front insulator 30 is arranged so as to cover part of the surface of the teeth.

[0061] The coil 31 is attached to the stator core 28 via the rear insulator 29 and the front insulator 30. Multiple coils 31 are arranged. The coils 31 are arranged around the teeth of the stator core 28 via the rear insulator 29 and the front insulator 30. The coils 31 and the stator core 28 are electrically insulated by the front insulator 30 and the rear insulator 29. The multiple coils 31 are connected via fusing terminals 36.

[0062] The rotor 27 rotates about a rotation axis AX and includes a rotor core 32, a rotor shaft 33, and a rotor magnet .

[0063] The rotor core 32 and the rotor shaft 33 are each made of steel. The rotor core 32 is substantially cylindrical. The rotor shaft 33 is disposed radially inside the rotor core 32. The rotor core 32 and the rotor shaft 33 are fixed together. The rear end of the rotor shaft 33 protrudes rearward from the rear end surface of the rotor core 32. The front end of the rotor shaft 33 protrudes rearward from the front end surface of the rotor core 32.

[0064] The rotor magnet 34 is fixed to the rotor core 32. The rotor magnet 34 is disposed inside the rotor core 32.

[0065] A sensor board 35 is attached to the front insulator 30. The sensor board 35 is fixed to the front insulator 30 with screws 30S. The sensor board 35 has an annular circuit board and a rotation detection element supported by the circuit board. At least a portion of the sensor board 35 faces the front end surface of the rotor magnet 34. The rotation detection element detects the position of the rotor magnet 34, thereby detecting the position of the rotor 27 in the rotational direction.

[0066] The rear end of the rotor shaft 33 is rotatably supported by a rear rotor bearing 37. The front end of the rotor shaft 33 is rotatably supported by a front rotor bearing 38. The rear rotor bearing 37 is held by the rear cover 3. The front rotor bearing 38 is held by the bearing box 24.

[0067] The front end of the rotor shaft 33 is disposed in the internal space of the hammer case 4 through an opening provided in the rear annular portion 24A of the bearing box 24.

[0068] A pinion gear 41 is fixed to the front end of the rotor shaft 33. The pinion gear 41 is connected to at least a part of the reduction mechanism 7. The rotor shaft 33 is connected to the reduction mechanism 7 via the pinion gear 41.

[0069] The reduction mechanism 7 connects the rotor shaft 33 and the spindle 8. The gears of the reduction mechanism 7 are driven by the rotor 27. 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 33. The reduction mechanism 7 is disposed forward of the stator 26. The reduction mechanism 7 includes a planetary gear mechanism.

[0070] 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.

[0071] The internal gear 43 is fixed to the large cylindrical portion 4A of the hammer case 4. The internal gear 43 is always non-rotatable relative to the hammer case 4. An O-ring 39A is disposed at the boundary between the rear end of the internal gear 43 and the bearing box 24. An O-ring 39B is disposed at the boundary between the bearing box 24 and the hammer case 4.

[0072] When the rotor shaft 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 33.

[0073] The spindle 8 is rotated about the rotation axis AX by the motor 6. The spindle 8 is rotated by the rotor 27. The spindle 8 is rotated by the rotational force of the rotor 27 transmitted via the reduction mechanism 7. The spindle 8 transmits the rotational force of the motor 6 to the anvil 10 via a ball 48 and a hammer 47. At least a portion of the spindle 8 is disposed forward 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. At least a portion of the spindle 8 is disposed rearward of the anvil 10.

[0074] The spindle 8 has a spindle shaft portion 8A, a first flange portion 8B, a second flange portion 8C, a connecting portion 8D, a holding portion 8E, and a spindle protrusion portion 8F.

[0075] The spindle shaft portion 8A is rod-shaped and long in the front-rear direction. The central axis of the spindle shaft portion 8A coincides with the rotation axis AX. The first flange portion 8B extends radially outward from the rear end of the outer circumferential surface of the spindle shaft portion 8A. The second flange portion 8C is located rearward of the first flange portion 8B. The second flange portion 8C is annular. The connecting portion 8D connects a portion of the first flange portion 8B to a portion of the second flange portion 8C. The retaining portion 8E protrudes rearward from the rear surface of the second flange portion 8C. The retaining portion 8E is cylindrical. The spindle protrusion 8F protrudes forward from the front end of the spindle shaft portion 8A. The front end of the pin 42P is supported by the first flange portion 8B. The rear end of the pin 42P is supported by the second flange portion 8C. The planetary gear 42 is located between the first flange portion 8B and the second flange portion 8C. The planetary gear 42 is rotatably supported by the first flange portion 8B and the second flange portion 8C via pins 42P. The spindle bearing 44 is disposed around the holding portion 8E. The spindle bearing 44 holds the holding portion 8E. The spindle bearing 44 is held in the bearing box 24.

[0076] 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 large cylindrical portion 4A of the hammer case 4.

[0077] The hammer 47 is disposed forward of the reduction mechanism 7. The hammer 47 is disposed around the spindle 8. The hammer 47 is disposed around the spindle shaft portion 8A. The hammer 47 is held by the spindle shaft portion 8A. The ball 48 is disposed between the spindle 8 and the hammer 47.

[0078] The hammer 47 has a body portion 47A, an outer cylindrical portion 47B, an inner cylindrical portion 47C, and a hammer protrusion portion 47D. The body portion 47A is disposed around the spindle shaft portion 8A. The body portion 47A is annular. The outer cylindrical portion 47B and the inner cylindrical portion 47C each protrude rearward from the body portion 47A. The outer cylindrical portion 47B is disposed radially outward from the inner cylindrical portion 47C. A recess 47E is defined by the rear surface of the body portion 47A, the inner peripheral surface of the outer cylindrical portion 47B, and the outer peripheral surface of the inner cylindrical portion 47C. The recess 47E is recessed forward from the rear end of the hammer 47. The recess 47E is ring-shaped. The spindle shaft portion 8A is disposed radially inward from the body portion 47A and the inner cylindrical portion 47C. The inner cylindrical portion 47C has an inner peripheral surface 47S that contacts the outer peripheral surface 8S of the spindle shaft portion 8A. The hammer protrusions 47D protrude forward from the body portion 47A. Two hammer protrusions 47D are provided.

[0079] 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 mechanism 7 and the spindle 8. 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.

[0080] The washer 50 is disposed inside the recess 47E. The washer 50 is supported by the hammer 47 via a plurality of balls 54. The balls 54 are disposed forward of the washer 50. The balls 54 are disposed between the rear surface of the body portion 47A and the front surface of the washer 50.

[0081] The coil spring 49 is disposed around the spindle shaft portion 8A. The rear end of the coil spring 49 is supported by the first flange portion 8B. The front end of the coil spring 49 is disposed inside the recess 47E and is supported by a washer 50. The coil spring 49 constantly generates an elastic force that moves the hammer 47 forward.

[0082] The balls 48 are made of a metal such as steel. The balls 48 are disposed between the spindle shaft portion 8A and the body portion 47A. The spindle shaft portion 8A has a spindle groove 8G in which at least a portion of the balls 48 are disposed. The spindle groove 8G is provided on a portion of the outer circumferential surface of the spindle shaft portion 8A. The hammer 47 has a hammer groove 47G in which at least a portion of the balls 48 are disposed. The hammer groove 47G is provided on a portion of the inner circumferential surfaces of the body portion 47A and the inner cylinder portion 47C.

[0083] Two balls 48 are provided. Two spindle grooves 8G are provided on the outer peripheral surface of the spindle shaft portion 8A. Two hammer grooves 47G are provided on the inner peripheral surfaces of the body portion 47A and the inner cylindrical portion 47C. One ball 48 is disposed between one spindle groove 8G and one hammer groove 47G. The other ball 48 is disposed between the other spindle groove 8G and the other hammer groove 47G. The balls 48 can roll inside the spindle groove 8G and the hammer groove 47G. The hammer 47 can move along with the balls 48. The spindle 8 and the hammer 47 can move relative to each other in the axial and rotational directions within a movable range defined by the spindle groove 8G and the hammer groove 47G.

[0084] The anvil 10 is disposed forward of the motor 6. The anvil 10 is an output part of the impact 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 spindle 8. At least a portion of the anvil 10 is disposed forward of the hammer 47. The anvil 10 is struck by the hammer 47 in the rotational direction.

[0085] The anvil 10 has an anvil shaft portion 10A and an anvil protrusion portion 10B. The anvil shaft portion 10A is rod-shaped and long in the front-to-rear direction. The central axis of the anvil shaft portion 10A coincides with the rotation axis AX. The anvil protrusion portion 10B is provided at the rear end portion of the anvil shaft portion 10A. The anvil protrusion portion 10B protrudes radially outward from the rear end portion of the anvil shaft portion 10A. Two anvil protrusion portions 10B are provided. A washer 56 is arranged in front of the anvil protrusion portion 10B. The washer 56 is supported on the rear surface of the connection portion 4C. The washer 56 prevents contact between the front surface of the anvil protrusion portion 10B and the hammer case 4.

[0086] A tool hole 10C is provided in the front end surface of the anvil 10. An anvil recess 10D is provided in the rear end surface of the anvil 10. The tool hole 10C is formed to extend rearward from the front end surface of the anvil shaft portion 10A. A tool bit is inserted into the tool hole 10C. The tool bit is attached to the anvil 10. The anvil recess 10D is recessed forward from the rear end surface of the anvil 10. A spindle protrusion 8F is disposed in the anvil recess 10D.

[0087] Alternatively, an anvil protrusion may be provided so as to protrude rearward from the rear end surface of the anvil 10, and a spindle recess in which the anvil protrusion is disposed may be provided on the front end surface of the spindle 8.

[0088] The anvil 10 is rotatably supported by the anvil 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 aligned. The anvil 10 rotates around the rotation axis AX. The anvil bearing 46 is disposed around the anvil shaft portion 10A. The anvil bearing 46 is disposed inside the small cylindrical portion 4B of the hammer case 4. The anvil bearing 46 is held by the small cylindrical portion 4B of the hammer case 4. The anvil bearing 46 rotatably supports the front portion of the anvil shaft portion 10A. In this embodiment, two anvil bearings 46 are disposed in the front-to-rear direction. A washer 58 is disposed between the front anvil bearing 46 and the rear anvil bearing 46. A support member 57 is disposed behind the rear anvil bearing 46. An example of the support member 57 is a snap ring. The support member 57 is disposed in a groove provided on the inner circumferential surface of the small cylindrical portion 4B. The support member 57 prevents the anvil bearing 46 from slipping out rearward from the small cylindrical portion 4B. An O-ring 45 is disposed between the anvil bearing 46 and the anvil shaft portion 10A.

[0089] The hammer protrusion 47D can come into contact with the anvil protrusion 10B. When the motor 6 is driven while the hammer protrusion 47D and the anvil protrusion 10B are in contact with each other, the anvil 10 rotates together with the hammer 47 and the spindle 8.

[0090] 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 8G and the hammer groove 47G. When the spindle 8 rotates while the rotation of the hammer 47 is stopped, the outer peripheral surface 8S of the spindle 8 and the inner peripheral surface 47S of the hammer 47 slide against each other. The hammer 47 receives force from the ball 48 and moves rearward along with the ball 48. That is, the hammer 47 moves rearward as the spindle 8 rotates while the rotation of the anvil 10 is stopped. As the hammer 47 moves rearward, the contact between the hammer protrusion 47D and the anvil protrusion 10B is released.

[0091] As described above, the coil spring 49 constantly generates an elastic force that moves the hammer 47 forward. After moving backward, the hammer 47 moves forward due to the elastic force of the coil spring 49. When the hammer 47 moves forward, it receives a rotational force from the ball 48. That is, the hammer 47 moves forward while rotating. When the hammer 47 moves forward while rotating, it comes into contact with the anvil protrusion 10B while rotating. As a result, the anvil protrusion 10B is struck in the rotational direction by the hammer protrusion 47D 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.

[0092] 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 10C of the anvil 10. The tool holding mechanism 11 is capable of attaching and detaching the tool bit.

[0093] The tool holding mechanism 11 includes a ball 71 , a leaf spring 72 , a sleeve 73 , a coil spring 74 , and a positioning member 75 .

[0094] The anvil 10 has a support recess 76 that supports the ball 71. The support recess 76 is formed in the outer surface of the anvil shaft portion 10A. In this embodiment, two support recesses 76 are formed in the anvil shaft portion 10A.

[0095] 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.

[0096] A through hole connecting the inner surface of the support recess 76 and the inner surface of the tool hole 10C is formed in the anvil shaft portion 10A. The diameter of the ball 71 is smaller than the diameter of the through hole. With the ball 71 supported by the support recess 76, it is disposed inside the tool hole 10C via at least a portion of the ball 71. The ball 71 can fix a tool bit inserted into the tool hole 10C. 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.

[0097] 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 10A. The leaf spring 72 generates an elastic force that moves the ball 71 forward.

[0098] The sleeve 73 is a cylindrical member. The sleeve 73 is disposed around the anvil shaft portion 10A. The sleeve 73 is movable in the axial direction around the anvil shaft portion 10A. 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.

[0099] The sleeve 73 is movable around the anvil shaft portion 10A 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.

[0100] 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.

[0101] 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.

[0102] 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 portion 10A. The blocking position is set rearward of the allowable position. The coil spring 74 generates an elastic force that moves the sleeve 73 rearward.

[0103] The positioning member 75 is a ring-shaped member fixed to the outer surface of the anvil shaft portion 10A. 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.

[0104] The fan 12 is disposed rearward 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 rear of the rotor shaft 33 via a bushing 12A. The fan 12 is disposed between the rear rotor bearing 37 and the stator 26. The fan 12 rotates with the rotation of the rotor 27. As the rotor shaft 33 rotates, the fan 12 rotates together with the rotor shaft 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 19. The air that has flowed into the internal space of the housing 2 circulates through the internal space of the housing 2, thereby cooling the motor 6. As the fan 12 rotates, the air that has circulated through the internal space of the housing 2 flows out into the external space of the housing 2 through the air exhaust 20.

[0105] 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. 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 this 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 impact tool 1. The motor 6 is driven based on the power supplied from the battery pack 25. The operation display unit 16 is operated by the power supplied from the battery pack 25.

[0106] The trigger lever 14 is provided on 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.

[0107] 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. 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.

[0108] 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 an operation button 16A. There may be one or more operation buttons 16A. In the embodiment, a plurality of operation buttons 16A are provided. When the operator operates the operation button 16A, the operation mode of the motor 6 is switched.

[0109] 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 bit attached to the anvil 10 and the area around the tool bit with the illumination light. In this embodiment, the light assemblies 18 are disposed on the left and right sides of the hammer case cover 51. The light assembly 18 includes a circuit board 18A, a light-emitting element 18B supported by the circuit board 18A, and an optical member 18C through which light emitted from the light-emitting element 18B passes.

[0110] The position of the light emitting element 18B is not limited. The light emitting element 18B may be disposed above the trigger lever 14, for example.

[0111] <Lubricant supply> The spindle 8 has an internal space 60. An opening 59 is provided in the rear end surface of the spindle 8. In this embodiment, the opening 59 is provided in the rear end portion of the holding portion 8E. The internal space 60 is formed inside the spindle 8 so as to extend forward from the opening 59.

[0112] The internal space 60 includes a first space 61 and a second space 62. The first space 61 is disposed forward of the second space 62. The rear end of the first space 61 is connected to the front end of the second space 62. The opening 59 is provided at the rear end of the second space 62. In a cross section perpendicular to the rotation axis AX, the first space 61 and the second space 62 each have a circular shape. The inner diameter of the first space 61 is smaller than the inner diameter of the second space 62. A step portion 63 is provided at the boundary between the rear end of the first space 61 and the front end of the second space 62.

[0113] The inner diameter of the first space 61 may be larger than the inner diameter of the second space 62.

[0114] Lubricating oil is stored in the first space 61. The lubricating oil includes grease. In the embodiment, the first space 61 includes a rear space 61A connected to the front end of the second space 62, and a front space 61B disposed forward of the rear space 61A. The rear end of the front space 61B is connected to the front end of the rear space 61A. The inner diameter of the front space 61B is smaller than the inner diameter of the rear space 61A.

[0115] The impact tool 1 includes a lid 5 that closes the opening 59. The lid 5 prevents the lubricating oil stored in the internal space 60 from leaking from the opening 59. The lid 5 is inserted into the internal space 60 through the opening 59. The lid 5 is disposed in the second space 62.

[0116] The lid 5 is substantially cylindrical. The outer peripheral surface of the lid 5 contacts the inner peripheral surface of the second space 62. The peripheral edge of the front surface of the lid 5 is supported by the step portion 63.

[0117] The lid 5 may be made of metal, synthetic resin, or rubber. In the embodiment, the lid 5 is made of felt. An example of felt is wool felt. Before the lid 5 is inserted into the second space 62, the outer diameter of the lid 5 is larger than the inner diameter of the second space 62. A lid 5 made of felt is deformable. The lid 5 is inserted into the second space 62 while being crushed. When the lid 5, which has an outer diameter larger than the inner diameter of the second space 62, is inserted into the second space 62 while being crushed, the outer surface of the lid 5 comes into close contact with the inner surface of the second space 62.

[0118] The pinion gear 41 is disposed in the second space 62. In the second space 62, the pinion gear 41 is disposed rearward of the lid 5. The pinion gear 41 is inserted into the second space 62 through the opening 59. After the lid 5 is inserted into the second space 62 through the opening 59, the pinion gear 41 fixed to the front end of the rotor shaft 33 is inserted into the second space 62 through the opening 59.

[0119] The spindle 8 has a first supply port 81, a second supply port 82, and a third supply port 83.

[0120] The first supply port 81 is provided on the outer peripheral surface of the spindle shaft portion 8A. The first supply port 81 supplies lubricating oil from the first space 61 between the spindle 8 and the hammer 47. In this embodiment, the first supply port 81 supplies lubricating oil between the outer peripheral surface 8S of the spindle shaft portion 8A and the inner peripheral surface 47S of the inner cylinder portion 47C. The first supply port 81 is connected to the rear space 61A of the first space 61 via a first flow path 91 formed inside the spindle shaft portion 8A. The first flow path 91 is provided to extend radially outward from the rear space 61A so as to connect the rear space 61A and the first supply port 81. Due to the centrifugal force of the spindle 8, the lubricating oil contained in the rear space 61A flows through the first flow path 91 toward the first supply port 81. The lubricating oil supplied from the rear space 61A to the first supply port 81 via the first flow path 91 is supplied between the outer peripheral surface 8S of the spindle shaft portion 8A and the inner peripheral surface 47S of the inner cylindrical portion 47C.

[0121] As described above, when the spindle 8 rotates while the hammer 47 is stopped from rotating, the outer peripheral surface 8S of the spindle 8 slides against the inner peripheral surface 47S of the hammer 47. By supplying lubricating oil between the sliding surfaces, that is, the outer peripheral surface 8S and the inner peripheral surface 47S, wear or seizure of the outer peripheral surface 8S and the inner peripheral surface 47S is suppressed.

[0122] A plurality of first supply ports 81 are provided in the circumferential direction. In the embodiment, the first supply ports 81 include a first supply port 81A and a first supply port 81B that is provided at a position different from that of the first supply port 81A in the circumferential direction. In the front-rear direction, the positions of the first supply ports 81A and 81B are substantially the same.

[0123] The second supply port 82 is provided on the outer peripheral surface of the spindle shaft portion 8A. The second supply port 82 is provided forward of the first supply port 81 on the outer peripheral surface of the spindle shaft portion 8A. The second supply port 82 supplies lubricating oil from the first space 61 to the balls 48. The second supply port 82 also supplies lubricating oil between the outer peripheral surface of the spindle shaft portion 8A and the inner peripheral surface of the inner cylinder portion 47C. By supplying lubricating oil to the surface of the balls 48, the lubricating oil is supplied to the inner surfaces of the spindle groove 8G and the hammer groove 47G in which the balls 48 roll. The second supply port 82 is connected to the front space 61B of the first space 61 via a second flow path 92 formed inside the spindle shaft portion 8A. The second flow path 92 is provided to extend radially outward from the front space 61B so as to connect the front space 61B and the second supply port 82. The centrifugal force of the spindle 8 causes the lubricating oil stored in the front space 61B to flow through the second flow path 92 toward the second supply port 82. The lubricating oil supplied from the front space 61B to the second supply port 82 through the second flow path 92 is supplied to the surface of the ball 48. The lubricating oil supplied from the front space 61B to the second supply port 82 through the second flow path 92 is also supplied between the outer peripheral surface of the spindle shaft portion 8A and the inner peripheral surface 47S of the inner cylinder portion 47C.

[0124] A plurality of second supply ports 82 are provided in the circumferential direction. In the embodiment, the second supply ports 82 include a second supply port 82A and a second supply port 82B that is provided at a different position in the circumferential direction from the second supply port 82A. In the front-rear direction, the positions of the second supply ports 82A and the second supply ports 82B are substantially the same.

[0125] The first supply port 81 and the second supply port 82 are arranged at different positions in the circumferential direction. In the embodiment, the first supply port 81 and the second supply port 82 are arranged at positions that are different by 90 degrees in the circumferential direction. The first supply port 81A and the first supply port 81B are arranged at positions that are different by 180 degrees in the circumferential direction. The second supply port 82A and the second supply port 82B are arranged at positions that are different by 180 degrees in the circumferential direction. In the circumferential direction, when the position of the first supply port 81A is set to the 0-degree position, the second supply port 82A is arranged at a position of 90 degrees, the first supply port 81B is arranged at a position of 180 degrees, and the second supply port 82B is arranged at a position of 270 degrees.

[0126] The relative angle between the first supply port 81 and the second supply port 82 in the circumferential direction is an example. The number of first supply ports 81 does not have to be two, but may be one, or any number of three or more. The number of second supply ports 82 does not have to be two, but may be one, or any number of three or more.

[0127] The third supply port 83 is provided on the front end surface of the spindle 8. The third supply port 83 supplies lubricating oil from the first space 61 to between the spindle 8 and the anvil 10. In this embodiment, the third supply port 83 is provided on the front end surface of the spindle protrusion 8F. In this embodiment, the third supply port 83 supplies lubricating oil between the surface of the spindle protrusion 8F and the inner surface of the anvil recess 10D. The third supply port 83 is connected to the front end of the front space 61B. The lubricating oil supplied from the front space 61B to the third supply port 83 is supplied between the surface of the spindle protrusion 8F and the inner surface of the anvil recess 10D.

[0128] Alternatively, a spindle recess may be provided at the front end of the spindle shaft portion 8A, and an anvil protrusion to be placed in the spindle recess may be provided on the rear end surface of the anvil 10. The third supply port 83 may be provided on the inner surface of the spindle recess.

[0129] A first groove 47R is provided on the inner circumferential surface of the inner cylindrical portion 47C of the hammer 47. The first groove 47R is formed so as to be recessed radially outward from the inner circumferential surface of the inner cylindrical portion 47C. The first groove 47R is formed so as to surround the spindle shaft portion 8A. The first groove 47R is disposed forward of the first supply port 81. In the front-rear direction, the first groove 47R is disposed between the first supply port 81 and the second supply port 82. The first groove 47R may be disposed rearward of the first supply port 81 or may be disposed so as to face the first supply port 81. Lubricating oil is accommodated in the first groove 47R. The lubricating oil accommodated in the first groove 47R is supplied between the outer circumferential surface of the spindle shaft portion 8A and the inner circumferential surface of the inner cylindrical portion 47C.

[0130] A second groove 8R is provided on the outer peripheral surface of the spindle protrusion 8F. The second groove 8R is formed so as to recess radially inward from the outer peripheral surface of the spindle protrusion 8F. The second groove 8R is formed so as to surround the rotation axis AX. Lubricating oil is accommodated in the second groove 8R. The lubricating oil accommodated in the second groove 8R is supplied between the surface of the spindle protrusion 8F and the inner surface of the anvil recess 10D.

[0131] In addition, if a spindle recess is provided at the front end of the spindle shaft portion 8A and an anvil protrusion is provided on the rear end surface of the anvil 10 to be placed in the spindle recess, the second groove 8R may be provided on the inner surface of the spindle recess.

[0132] <Operation of impact tool> Next, the operation of the impact tool 1 will be described. For example, when performing a screwdriver operation on a workpiece, a tool bit (driver bit) to be used for the screwdriver operation is inserted into the tool hole 10C of the anvil 10. The tool bit inserted into the tool hole 10C 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 with the index finger of the right hand. 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 the light assembly 18 is simultaneously illuminated. When the motor 6 is started, the rotor shaft 33 of the rotor 27 rotates. When the rotor shaft 33 rotates, the rotational force of the rotor shaft 33 is transmitted to the planetary gear 42 via the pinion gear 41. The planetary gear 42, meshed 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 rotational speed lower than the rotational speed of the rotor shaft 33.

[0133] When the spindle 8 rotates while the hammer protrusion 47D and the anvil protrusion 10B 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.

[0134] As the screw tightening operation progresses, if a load greater than a predetermined value acts on the anvil 10, the rotation of the anvil 10 and the hammer 47 stops. When the spindle 8 rotates while the hammer 47 is stopped, the hammer 47 moves rearward. As the hammer 47 moves rearward, contact between the hammer protrusion 47D and the anvil protrusion 10B is released. The hammer 47, which has moved rearward, moves forward while rotating due to the elastic force of the coil spring 49. As the hammer 47 moves forward while rotating, the anvil 10 is struck in the rotational direction by the hammer 47. As a result, the anvil 10 rotates around the rotation axis AX with high torque. Therefore, the screw is tightened into the workpiece with high torque.

[0135] <Effects> As described above, in the embodiment, the impact tool 1 may include the motor 6, the spindle 8, the hammer 47, the anvil 10, and the lid 5. At least a portion of the spindle 8 may be disposed forward of the motor 6. The spindle 8 may be rotated by the motor 6. The hammer 47 may be disposed around the spindle 8. At least a portion of the anvil 10 may be disposed forward of the spindle 8. The anvil 10 may be struck by the hammer 47 in the rotational direction. An internal space 60 may be formed inside the spindle 8. The internal space 60 may be formed to extend forward from an opening 59 provided in the rear end surface of the spindle 8. The internal space 60 may include a first space 61 that accommodates lubricating oil and a second space 62 in which the lid 5 is disposed. The second space 62 may be disposed rearward of the first space 61. The rear end of the first space 61 may be connected to the front end of the second space 62. The opening 59 may be provided in the rear end of the second space 62. The lid 5 may be inserted into the second space 62 through the opening 59. A first supply port 81 may be provided on the outer peripheral surface 8S of the spindle 8 to supply lubricating oil from the first space 61 to between the spindle 8 and the hammer 47.

[0136] In the above configuration, the lid 5 is disposed in the second space 62, which is located behind the first space 61 in which the lubricating oil is stored. This prevents the lubricating oil stored in the first space 61 from leaking through the opening 59. This prevents the amount of lubricating oil supplied from the first supply port 81 between the spindle 8 and the hammer 47 from becoming too small. This prevents wear or seizure of the spindle 8 and the hammer 47, and prevents the life of the impact tool 1 from becoming shorter.

[0137] In an embodiment, the lid 5 may be made of felt.

[0138] The above configuration prevents a decrease in workability when inserting the lid 5 into the second space 62 from the opening 59. Because the felt is deformable, the person assembling the impact tool 1 can insert the lid 5 into the second space 62 with good workability by crushing the felt while inserting it into the second space 62. Furthermore, by inserting the felt, which has an outer diameter larger than the inner diameter of the second space 62, into the second space 62 while crushing it, the outer peripheral surface of the felt comes into close contact with the inner peripheral surface of the second space 62. Therefore, the sealing performance between the outer peripheral surface of the felt and the inner peripheral surface of the second space 62 is improved, effectively preventing the lubricating oil contained in the first space 61 from leaking through the opening 59.

[0139] In the embodiment, the inner diameter of the first space 61 may be smaller than the inner diameter of the second space 62.

[0140] In the above configuration, the lid 5 having an outer diameter larger than the inner diameter of the first space 61 is placed in the second space 62.

[0141] In the embodiment, a step 63 may be provided at the boundary between the rear end of the first space 61 and the front end of the second space 62. The lid 5 may be supported by the step 63.

[0142] In the above configuration, the lid 5 inserted into the second space 62 from the opening 59 is prevented from entering the first space 61 by the step portion 63. The lid 5 is positioned in the front-rear direction by the step portion 63.

[0143] In the embodiment, the hammer 47 may have a body portion 47A and an inner cylindrical portion 47C that protrudes rearward from the body portion 47A and has an inner circumferential surface 47S that contacts the outer circumferential surface 8S of the spindle 8. The first supply port 81 may supply lubricating oil between the outer circumferential surface 8S of the spindle 8 and the inner circumferential surface 47S of the inner cylindrical portion 47C.

[0144] In the above configuration, lubricating oil is supplied from the first space 61 between the outer peripheral surface 8S of the spindle 8 and the inner peripheral surface 47S of the inner cylindrical portion 47C, thereby suppressing wear or seizure between the outer peripheral surface 8S of the spindle 8 and the inner peripheral surface 47S of the inner cylindrical portion 47C.

[0145] In the embodiment, a plurality of first supply ports 81 may be provided in the circumferential direction.

[0146] In the above configuration, a plurality of first supply ports 81 are provided in the circumferential direction, so that lubricating oil is evenly supplied between the outer peripheral surface 8S of the spindle 8 and the inner peripheral surface 47S of the inner cylindrical portion 47C.

[0147] In the embodiment, the impact tool 1 may include a first groove 47R that is provided on the inner circumferential surface 47S of the inner cylindrical portion 47C and that accommodates lubricating oil.

[0148] In the above configuration, lubricating oil is supplied from the first groove 47R between the outer peripheral surface 8S of the spindle 8 and the inner peripheral surface 47S of the inner cylindrical portion 47C, thereby suppressing wear or seizure between the outer peripheral surface 8S of the spindle 8 and the inner peripheral surface 47S of the inner cylindrical portion 47C.

[0149] In the embodiment, the first groove 47R may be provided in front of the first supply port 81.

[0150] In the above configuration, the first supply port 81 and the first groove 47R are positioned at different positions in the front-rear direction, so that lubricating oil is evenly supplied between the outer peripheral surface 8S of the spindle 8 and the inner peripheral surface 47S of the inner cylindrical portion 47C.

[0151] In an embodiment, the impact tool 1 may include a ball 48 arranged between the spindle 8 and the hammer 47, and a second supply port 82 located on the outer surface 8S of the spindle 8 forward of the first supply port 81 and supplying lubricating oil from the first space 61 to the ball 48.

[0152] In the above configuration, lubricating oil is supplied to the balls 48 from the first space 61, thereby suppressing wear of the balls 48. In addition, wear of the inner surfaces of the spindle groove 8G and the hammer groove 47G that come into contact with the balls 48 is suppressed.

[0153] In the embodiment, a plurality of second supply ports 82 may be provided in the circumferential direction.

[0154] In the above configuration, a plurality of second supply ports 82 are provided in the circumferential direction, so that the lubricating oil is supplied to the balls 48 evenly.

[0155] In the embodiment, the first supply port 81 and the second supply port 82 may be disposed at different positions in the circumferential direction.

[0156] In the above configuration, the lubricating oil from the first space 61 is evenly supplied to each of the spindle 8, the hammer 47, and the ball 48.

[0157] In the embodiment, the impact tool 1 may include a third supply port 83 that is provided on the front end surface of the spindle 8 and that supplies the lubricating oil from the first space 61 to the space between the spindle 8 and the anvil 10 .

[0158] In the above configuration, the lubricating oil is supplied from the first space 61 between the spindle 8 and the anvil 10, so that wear of the spindle 8 and the anvil 10 is suppressed.

[0159] In an embodiment, the spindle 8 may have a spindle shaft portion 8A and a spindle protrusion 8F protruding forward from the front end of the spindle shaft portion 8A. The anvil 10 may have an anvil recess 10D provided on the rear end surface of the anvil 10, in which the spindle protrusion 8F is disposed. The hammer 47 may be disposed around the spindle shaft portion 8A. The third supply port 83 may be provided on the front end surface of the spindle protrusion 8F.

[0160] In the above configuration, lubricating oil is supplied from the first space 61 between the surface of the spindle protrusion 8F and the inner surface of the anvil recess 10D, thereby suppressing wear between the surface of the spindle protrusion 8F and the inner surface of the anvil recess 10D.

[0161] In the embodiment, the impact tool 1 may include a second groove 8R that is provided on the outer peripheral surface of the spindle protrusion 8F and that accommodates lubricating oil.

[0162] In the above configuration, lubricating oil is supplied from the second groove 8R between the surface of the spindle protrusion 8F and the inner surface of the anvil recess 10D, thereby suppressing wear between the surface of the spindle protrusion 8F and the inner surface of the anvil recess 10D.

[0163] [Variations] FIG. 7 is a cross-sectional view schematically illustrating a spindle 8 and an anvil 10 according to a modified example. In the above-described embodiment, the spindle 8 includes a spindle shaft portion 8A and a spindle protrusion 8F protruding forward from the front end of the spindle shaft portion 8A. The anvil 10 includes an anvil recess 10D provided on the rear end surface of the anvil 10 and in which the spindle protrusion 8F is disposed. The spindle 8 may include a spindle shaft portion 8A and a spindle recess 8H recessed rearward from the front end of the spindle shaft portion 8A. The anvil 10 may include an anvil protrusion 10E provided so as to protrude rearward from the rear end surface of the anvil 10 and disposed in the spindle recess 8H. The third supply port 83 may be provided on the inner surface of the spindle recess 8H. Furthermore, a second groove 8R for accommodating lubricating oil may be provided on the inner circumferential surface of the spindle recess 8H.

[0164] 8 is a cross-sectional view schematically showing a spindle 8 according to a modified example. In the above-described embodiment, the inner diameter of the first space 61 is smaller than the inner diameter of the second space 62. As shown in FIG. 8, the inner diameter of the first space 61 may be larger than the inner diameter of the second space 62.

[0165] In the above-described embodiment, the impact tool 1 is an impact driver. The impact tool 1 may be an impact wrench.

[0166] In the above-described embodiment, the power source for the impact tool 1 does not have to be the battery pack 25, and may be a commercial power source (AC power source). [Explanation of symbols]

[0167] 1...impact tool, 2...housing, 2L...left housing, 2R...right housing, 2S...screw, 3...rear cover, 3S...screw, 4...hammer case, 4A...large cylinder portion, 4B...small cylinder portion, 4C...connection portion, 5...lid, 6...motor, 7...reduction mechanism, 8...spindle, 8A...spindle shaft portion, 8B...first flange portion, 8C...second flange portion, 8D...connection portion, 8E...retaining portion, 8F...spindle protrusion portion, 8G...spindle groove, 8H...spindle recess portion, 8R...second groove, 8S...outer periphery, 9...impact mechanism, 10...anvil, 10A...anvil shaft portion, 10B...anvil protrusion part, 10C...tool hole, 10D...anvil recess, 10E...anvil protrusion, 11...tool holding mechanism, 12...fan, 12A...bush, 13...battery mounting part, 14...trigger lever, 15...forward / reverse switching lever, 16...operation display part, 16A...operation button, 18...light assembly, 18A...circuit board, 18B...light emitting element, 18C...optical member, 19...intake port, 20...exhaust port, 21...motor housing part, 22...grip part, 23...battery holding part, 24...bearing box, 24A...rear annular part, 24B...front annular part, 24C...connection part, 25...battery pack, 26...s Stator, 27...Rotor, 28...Stator core, 29...Rear insulator, 30...Front insulator, 30S...Screw, 31...Coil, 32...Rotor core, 33...Rotor shaft, 34...Rotor magnet, 35...Sensor board, 36...Fusing terminal, 37...Rear rotor bearing, 38...Front rotor bearing, 39A...O-ring, 39B...O-ring, 41...Pinion gear, 42...Planetary gear, 42P...Pin, 43...Internal gear, 44...Spindle bearing, 45...O-ring, 46...Anvil bearing, 47...Hammer, 47A...Body part, 47B...outer cylinder portion, 47C...inner cylinder portion, 47D...hammer protrusion portion, 47E...recess, 47G...hammer groove, 47R...first groove, 47S...inner peripheral surface, 48...ball, 49...coil spring, 50...washer, 51...hammer case cover, 52...bumper, 54...ball, 56...washer, 57...support member, 58...washer, 59...opening, 60...internal space, 61...first space, 61A...rear space, 61B...front space, 62...second space, 63...step portion, 71...ball, 72...leaf spring, 73...sleeve, 74...coil spring, 75...positioning member, 76...support recess,81...first supply port, 81A...first supply port, 81B...first supply port, 82...second supply port, 82A...second supply port, 82B...second supply port, 83...third supply port, 91...first flow path, 92...second flow path, AX...rotation axis.

Claims

1. A motor; a spindle at least a portion of which is disposed forward of the motor and which is rotated by the motor; a hammer disposed around the spindle; an anvil, at least a portion of which is disposed forward of the spindle and which is struck in a rotational direction by the hammer; an internal space formed inside the spindle so as to extend forward from an opening provided on a rear end surface of the spindle, the internal space including a first space for accommodating lubricating oil; a first supply port provided on an outer peripheral surface of the spindle for supplying lubricating oil from the first space to the space between the spindle and the hammer; a lid that is inserted through the opening, is disposed in a second space of the internal space that is connected to a rear end of the first space, and prevents the lubricating oil from leaking from the opening. Impact tool.

2. The lid is made of felt. The impact tool according to claim 1 .

3. The lid is made of metal, synthetic resin, or rubber. The impact tool according to claim 1 .

4. The inner diameter of the first space is smaller than the inner diameter of the second space. The impact tool according to claim 1 .

5. a step portion is provided at a boundary between a rear end portion of the first space and a front end portion of the second space, The lid is supported by the step portion.

5. The impact tool according to claim 4.

6. The inner diameter of the first space is larger than the inner diameter of the second space. The impact tool according to claim 1 .

7. the hammer has a body portion and an inner cylindrical portion that protrudes rearward from the body portion and has an inner peripheral surface that contacts an outer peripheral surface of the spindle, the first supply port supplies the lubricating oil between an outer circumferential surface of the spindle and an inner circumferential surface of the inner cylindrical portion. The impact tool according to claim 1 .

8. The first supply port is provided in plurality in the circumferential direction.

8. The impact tool according to claim 7.

9. a first groove provided on an inner circumferential surface of the inner cylindrical portion and configured to accommodate lubricating oil; 8. The impact tool according to claim 7.

10. a ball disposed between the spindle and the hammer; a second supply port provided on the outer peripheral surface of the spindle forward of the first supply port and supplying the lubricating oil from the first space to the balls, The impact tool according to claim 1 .

11. The second supply port is provided in plurality in the circumferential direction.

11. An impact tool according to claim 10.

12. The first supply port and the second supply port are disposed at different positions in the circumferential direction.

11. An impact tool according to claim 10.

13. a third supply port provided on a front end surface of the spindle for supplying lubricating oil from the first space to the space between the spindle and the anvil; The impact tool according to claim 1 .

14. the spindle has a spindle shaft portion and a spindle protrusion portion protruding forward from a front end portion of the spindle shaft portion, the anvil has an anvil recess provided on a rear end surface of the anvil and in which the spindle protrusion is disposed, The hammer is disposed around the spindle shaft portion, The third supply port is provided on a front end surface of the spindle protrusion.

14. An impact tool according to claim 13.

15. a second groove provided on the outer peripheral surface of the spindle protrusion and configured to accommodate lubricating oil; 15. An impact tool according to claim 14.

16. the spindle has a spindle shaft portion and a spindle recess portion recessed rearward from a front end portion of the spindle shaft portion, the anvil has an anvil protrusion provided on a rear end surface of the anvil and disposed in the spindle recess, The hammer is disposed around the spindle shaft portion, The third supply port is provided on the inner surface of the spindle recess.

14. An impact tool according to claim 13.

17. a second groove provided on an inner peripheral surface of the spindle recess and configured to accommodate lubricating oil; 17. An impact tool according to claim 16.

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