Impact tool and spindle

Abstract

To inhibit shortening of the life of an impact tool.SOLUTION: A hammer 47 is driven in a front and rear direction and a rotary direction according to a ball 48. A front part of a spindle 8 is provided with a first opening 61 to which a lubricant is input. A rear part of the spindle is provided with a second opening 62. A partition wall 60 is provided between the first opening and the second opening. The first opening extends at least to a first cam part 8G. The second opening extends at least to a deceleration mechanism part 7. A protrusion 10D provided at a rear end of an anvil 10 engages with a recess 8F provided at a front end of the first opening, in order to support the spindle.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] In the technical field related to impact tools, an impact tool as disclosed in Patent Document 1 is known. The impact tool disclosed in Patent Document 1 includes a spindle and a hammer externally mounted on the spindle. Grease is accommodated in a bottomed hole provided in the spindle. The grease accommodated in the bottomed hole is supplied between the spindle and the hammer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When grease leaks backward from the bottomed hole of the spindle, the amount of grease supplied between the spindle and the hammer decreases.

[0005] The technology disclosed in this specification aims to suppress the shortening of the life of the impact tool.

Means for Solving the Problems

[0006] This specification discloses an impact tool. The impact tool may include a motor, a speed reduction mechanism for reducing the rotation of the motor, a spindle that rotates by the output of the speed reduction mechanism and has a first cam portion, a hammer that is held by the spindle and has a second cam portion, a ball that contacts the first cam portion and the second cam portion, an anvil that is struck in the rotational direction by the hammer, a hammer case that houses the hammer, rotatably holds the anvil, and is filled with a lubricant, a tip tool holder disposed at the front portion of the anvil, and a coil spring that biases the hammer toward the anvil side. The hammer may be driven in the front-rear direction and the rotational direction by the ball. A first opening for filling a lubricant may be provided at the front portion of the spindle. A second opening may be provided at the rear portion of the spindle. A partition wall may be provided between the first opening and the second opening. The first opening may extend at least to the first cam portion. The second opening may extend at least to the speed reduction mechanism portion. A convex portion provided at the rear end portion of the anvil may be fitted into a concave portion provided at the front end portion of the first opening to support the spindle.

Advantages of the Invention

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

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

DETAILED DESCRIPTION OF THE INVENTION

[0009] In one or more embodiments, the impact tool may include a motor, a speed reduction mechanism that reduces the rotation of the motor, a spindle that rotates by the output of the speed reduction mechanism and has a first cam portion, a hammer that is held by the spindle and has a second cam portion, a ball that contacts the first cam portion and the second cam portion, an anvil that is struck in the rotational direction by the hammer, a hammer case that houses the hammer, rotatably holds the anvil, and is filled with a lubricant, a tip tool holder disposed at the front portion of the anvil, and a coil spring that biases the hammer toward the anvil side. The hammer may be driven in the front-rear direction and the rotational direction by the ball. A first opening into which a lubricant is placed may be provided at the front portion of the spindle. A second opening may be provided at the rear portion of the spindle. A partition wall may be provided between the first opening and the second opening. The first opening may extend at least to the first cam portion. The second opening may extend at least to the speed reduction mechanism. A convex portion provided at the rear end portion of the anvil may be fitted into a concave portion provided at the front end portion of the first opening to support the spindle.

[0010] In the above configuration, since the grease, which is the lubricant, is put into the first opening provided at the front portion of the spindle, leakage to the rear of the spindle is suppressed. Therefore, a decrease in the amount of grease supplied between the spindle and the hammer is suppressed. Accordingly, a shortening of the life of the impact tool is suppressed.

[0011] In one or more embodiments, in the front-rear direction parallel to the rotation axis of the motor, the first opening may be provided behind the concave portion and communicate with the concave portion.

[0012] In the above configuration, the grease contained in the first opening is supplied to the boundary between the concave portion of the spindle and the convex portion of the anvil. Accordingly, a shortening of the life of the impact tool is suppressed.

[0013] In one or more embodiments, in a plane orthogonal to the rotation axis of the motor, each of the recess and the first opening may be circular. The diameter of the first opening may be smaller than the diameter of the recess.

[0014] In the above configuration, the grease placed in the first opening is smoothly supplied to the boundary between the recess of the spindle and the convex portion of the anvil. Further, since the diameter of the recess is large, the spindle is stably supported by the anvil.

[0015] In one or more embodiments, in the front-rear direction, the dimension of the first opening may be larger than the dimension of the recess.

[0016] In the above configuration, since the dimension of the first opening is large in the front-rear direction, an appropriate amount of grease is placed in the first opening.

[0017] In one or more embodiments, in a plane orthogonal to the rotation axis of the motor, the second opening may be circular. The diameter of the first opening may be smaller than the diameter of the second opening.

[0018] In the above configuration, since the diameter of the first opening is not excessively large, a decrease in the strength of the spindle is suppressed.

[0019] In one or more embodiments, the diameter of the second opening may be smaller than the diameter of the recess.

[0020] In the above configuration, since the diameter of the second opening is not excessively large, a decrease in the strength of the spindle is suppressed.

[0021] In one or more embodiments, in the front-rear direction, the dimension of the first opening may be larger than the dimension of the second opening.

[0022] In the above configuration, since the dimension of the first opening is large in the front-rear direction, an appropriate amount of grease is placed in the first opening.

[0023] In one or more embodiments, the rotation axis of the motor, the central axis of the recess, the central axis of the first opening, and the central axis of the second opening may coincide.

[0024] In the above configuration, the eccentricity of the spindle is suppressed.

[0025] In one or more embodiments, the spindle may have a large-diameter cylindrical portion to which at least two gears are attached, and a small-diameter cylindrical portion extending forward from the large-diameter cylindrical portion. The first opening may be formed inside the small-diameter cylindrical portion.

[0026] In the above configuration, since the first opening is provided inside the small-diameter cylindrical portion, grease is smoothly supplied between the spindle and the hammer and between the spindle and the anvil, respectively.

[0027] In one or more embodiments, the small-diameter cylindrical portion may have a passage connecting the inner peripheral surface of the first opening and the outer peripheral surface of the small-diameter cylindrical portion.

[0028] In the above configuration, due to the centrifugal force when the spindle rotates, the grease placed in the first opening is supplied to the outer peripheral surface of the small-diameter cylindrical portion through the passage.

[0029] In one or more embodiments, the cross-sectional shape of the passage may be circular. The diameter of the passage may be smaller than the diameter of the first opening.

[0030] In the above configuration, since the diameter of the passage is small, an appropriate amount of grease is supplied from the first opening to the outer peripheral surface of the small-diameter cylindrical portion.

[0031] In one or more embodiments, the passage may be formed to extend in a direction perpendicular to the rotation axis of the motor.

[0032] In the above configuration, due to the centrifugal force when the spindle rotates, the grease placed in the first opening is smoothly supplied to the outer peripheral surface of the small-diameter cylindrical portion through the passage.

[0033] In one or more embodiments, at least two passages may be provided. In the circumferential direction of the rotation axis of the motor, the two passages may be provided at different positions from each other. In the front-rear direction parallel to the rotation axis of the motor, the two passages may be provided at the same position.

[0034] In the above configuration, due to the centrifugal force when the spindle rotates, the grease placed in the first opening is smoothly supplied to the outer peripheral surface of the small-diameter columnar portion through the passage.

[0035] In one or more embodiments, the impact tool may include a lid inserted into the first opening through a recess. The lid may be disposed in front of the rear end portion of the first opening.

[0036] In the above configuration, the grease placed between the lid and the rear end portion of the first opening is suppressed from being supplied between the spindle and the anvil, and the amount of grease supplied between the spindle and the hammer increases.

[0037] In one or more embodiments, the impact tool may include a lid inserted into the first opening through a recess. The lid may be disposed in front of the passage.

[0038] In the above configuration, the grease placed between the lid and the rear end portion of the first opening is suppressed from being supplied between the spindle and the anvil, and the amount of grease supplied between the spindle and the hammer increases.

[0039] In one or more embodiments, the lid may be made of felt.

[0040] With the above configuration, a decrease in workability when inserting a lid into the first opening is suppressed. Since the felt is deformable, an assembler of the impact tool can insert the lid into the first opening with good workability by inserting the felt into the first opening while crushing it. Further, since the felt having an outer diameter larger than the inner diameter of the first opening is inserted into the first opening while being crushed, the outer peripheral surface of the felt comes into close contact with the inner peripheral surface of the first opening. Therefore, since the sealing performance between the outer peripheral surface of the felt and the inner peripheral surface of the first opening is improved, leakage of the lubricating oil contained in the first opening through the opening at the front end of the first opening is effectively suppressed.

[0041] In one or more embodiments, the impact tool may include a sealing member that is disposed so as to surround the convex portion and seals the boundary between the concave portion and the convex portion.

[0042] With the above configuration, leakage of the grease supplied from the first opening between the concave portion and the convex portion to the outside of the boundary between the concave portion and the convex portion is suppressed.

[0043] In one or more embodiments, a grease groove may be provided on either the front end surface of the spindle or the rear end surface of the anvil that contacts the front end surface.

[0044] With the above configuration, since the grease is held in the grease groove, the lubricity between the spindle and the anvil is improved.

[0045] Hereinafter, embodiments will be described with reference to the drawings. In the embodiments, the terms left, right, front, rear, top, and bottom are used to describe the positional relationship of each part. These terms indicate the relative position or direction with respect to the center of the impact tool 1. The impact tool 1 has a motor 6 as a power source.

[0046] In the embodiment, the direction parallel to the rotation axis AX of the motor 6 is appropriately referred to as the axial direction, the direction of orbiting around the rotation axis AX is appropriately referred to as the circumferential direction or the rotational direction, and the radial direction of the rotation axis AX is appropriately referred to as the radial direction.

[0047] The rotation axis AX extends in the front-rear direction. The direction parallel to the rotation axis AX is the front-rear direction. One axial side is the front, and the other axial side is the rear. Also, in the radial direction, a position close to the rotation axis AX or a direction approaching it is appropriately referred to as the inner radial side, and a position far from the rotation axis AX or a direction separating from it is appropriately referred to as the outer radial side.

[0048] [First Embodiment] The first embodiment will be described.

[0049] <Impact Tool> FIG. 1 is a front perspective view showing the impact tool 1 according to the present embodiment. FIG. 2 is a side view showing the upper part of the impact tool 1 according to the present embodiment. FIG. 3 is a cross-sectional view showing the upper part of the impact tool 1 according to the present embodiment. FIG. 4 is a longitudinal sectional view showing the upper part of the impact tool 1 according to the present embodiment. FIG. 5 is a longitudinal sectional view showing a part of the impact tool 1 according to the present embodiment. FIG. 6 is a front exploded perspective view showing a part of the impact tool 1 according to the present embodiment. FIG. 7 is a rear exploded perspective view showing a part of the impact tool 1 according to the present embodiment.

[0050] In the present embodiment, the impact tool 1 is an impact driver which is a kind of screw tightening tool. The impact tool 1 includes a housing 2, a rear cover 3, a hammer case 4, a bearing box 24, a hammer case cover 5, a motor 6, a speed reduction mechanism portion 7, a spindle 8, a striking mechanism portion 9, an anvil 10, a tip tool holding portion 11, a fan 12, a battery mounting portion 13, a trigger lever 14, a forward / reverse switching lever 15, and a light assembly 16.

[0051] The housing 2 is made of synthetic resin. In the present embodiment, the housing 2 is made of nylon. The housing 2 includes a left housing 2L and a right housing 2R disposed to the right of the left housing 2L. The left housing 2L and the right housing 2R are fixed by a plurality of screws 2S. The housing 2 is composed of a pair of split housings.

[0052] The housing 2 has a motor housing portion 21, a grip portion 22, and a battery holding portion 23.

[0053] The motor housing portion 21 houses the motor 6. The motor housing portion 21 houses at least a part of the hammer case 4. The motor housing portion 21 is cylindrical.

[0054] The grip portion 22 is gripped by an operator. The grip portion 22 extends downward from the motor housing portion 21. The trigger lever 14 is provided at the upper portion of the grip portion 22.

[0055] The battery holding portion 23 holds the battery pack 25 via the battery mounting portion 13. The battery holding portion 23 is connected to the lower end portion of the grip portion 22. In each of the front-rear direction and the left-right direction, the outer dimensions of the battery holding portion 23 are larger than the outer dimensions of the grip portion 22.

[0056] The rear cover 3 is arranged so as to cover the opening at the rear end portion of the motor housing portion 21. The rear cover 3 is arranged behind the motor housing portion 21. The rear cover 3 houses at least a part of the fan 12. The fan 12 is arranged inside the rear cover 3. The rear cover 3 holds the rear-side rotor bearing 37. The rear cover 3 is made of synthetic resin. The rear cover 3 is fixed to the rear end portion of the motor housing portion 21 by two screws 3S.

[0057] The motor housing portion 21 has an air intake port 17. The rear cover 3 has an exhaust port 18. The air in the external space of the housing 2 flows into the internal space of the housing 2 through the air intake port 17. The air in the internal space of the housing 2 flows out to the external space of the housing 2 through the exhaust port 18.

[0058] The hammer case 4 houses at least a part of the speed reduction mechanism section 7, the spindle 8, the striking mechanism section 9, and at least a part of the anvil 10. The hammer case 4 is made of metal. In the present embodiment, the hammer case 4 is made of aluminum. The hammer case 4 is cylindrical. The hammer case 4 includes a large cylindrical portion 4A, a small cylindrical portion 4B, and a connecting portion 4C. The small cylindrical portion 4B is disposed forward of the large cylindrical portion 4A. The front end portion of the large cylindrical portion 4A and the rear end portion of the small cylindrical portion 4B are connected via the connecting portion 4C. The connecting portion 4C is annular. The outer diameter of the large cylindrical portion 4A is larger than the outer diameter of the small cylindrical portion 4B. The inner diameter of the large cylindrical portion 4A is larger than the inner diameter of the small cylindrical portion 4B.

[0059] The bearing box 24 houses at least a part of the speed reduction mechanism section 7. The bearing box 24 holds the front side 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 portion of the hammer case 4. The bearing box 24 has a rear side annular portion 24A, a front side annular portion 24B, and a connecting portion 24C. The front side annular portion 24B is disposed forward of the rear side annular portion 24A. The front end portion of the rear side annular portion 24A and the rear end portion of the front side annular portion 24B are connected via the connecting portion 24C. The connecting portion 24C is annular. The outer diameter of the rear side annular portion 24A is smaller than the outer diameter of the front side annular portion 24B. The inner diameter of the rear side annular portion 24A is smaller than the inner diameter of the front side annular portion 24B. The bearing box 24 and the hammer case 4 may be fixed by a screw portion or may be fixed by fitting (loose fit). For example, a thread may be formed on the outer peripheral portion of the front side annular portion 24B, and a thread groove may be formed on the inner peripheral portion of the large cylindrical portion 4A. The bearing box 24 and the hammer case 4 may be fixed by coupling the thread of the front side annular portion 24B and the thread groove of the large cylindrical portion 4A. The bearing box 24 and the hammer case 4 may be fixed by fitting the front side annular portion 24B into the large cylindrical portion 4A. The front side rotor bearing 38 is disposed radially inward of the rear side annular portion 24A. The spindle bearing 44 is disposed radially inward of the connecting portion 24C.

[0060] 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 part 21. The hammer case 4 is connected to the front part of the motor housing part 21. The bearing box 24 is fixed to each of the motor housing part 21 and the hammer case 4.

[0061] The hammer case cover 5 protects the hammer case 4. The hammer case cover 5 suppresses contact between the hammer case 4 and objects around the hammer case 4. The hammer case cover 5 is arranged to cover the outer peripheral surface of the large cylinder part 4A. Note that the hammer case cover 5 may be omitted.

[0062] The motor 6 is the power source of 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 part 21. At least a part of the rotor 27 is arranged inside the stator 26. The rotor 27 rotates with respect to the stator 26. The rotor 27 rotates about a rotation axis AX extending in the front-rear direction.

[0063] The stator 26 has a stator core 28, a rear insulator 29, a front insulator 30, and a coil 31.

[0064] The stator core 28 includes a plurality of laminated steel plates. The steel plate is a metal plate mainly made of iron. The stator core 28 is cylindrical. The stator core 28 is arranged radially outside the rotor 27. The stator core 28 has a plurality of teeth that support the coil 31.

[0065] Each of the rear insulator 29 and the front insulator 30 is an electric insulating member made of synthetic resin. Each of the rear insulator 29 and the front insulator 30 electrically insulates the stator core 28 and 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 a part of the surface of the teeth. The front insulator 30 is arranged so as to cover a part of the surface of the teeth.

[0066] The coil 31 is mounted on the stator core 28 via the rear insulator 29 and the front insulator 30. A plurality of 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 coil 31 and the stator core 28 are electrically insulated by the front insulator 30 and the rear insulator 29. The plurality of coils 31 are connected via the husing terminal 36.

[0067] The rotor 27 rotates about the rotation axis AX. The rotor 27 has a rotor core 32, a rotor shaft 33, a rotor magnet 34, and a sensor magnet 35.

[0068] Each of the rotor core 32 and the rotor shaft 33 is made of steel. In the present embodiment, the rotor core 32 and the rotor shaft 33 are integral. The rotor shaft 33 includes a rear shaft portion 33R protruding rearward from the rear end face of the rotor core 32 and a front shaft portion 33F protruding forward from the front end face of the rotor core 32.

[0069] The rotor magnet 34 is fixed to the rotor core 32. The rotor magnet 34 is arranged on the outer peripheral surface of the rotor core 32.

[0070] The sensor magnet 35 is fixed to the rotor core 32. The sensor magnet 35 is arranged on the front end face of the rotor core 32.

[0071] The sensor substrate 39 is attached to the front insulator 30. The sensor substrate 39 is fixed to the front insulator 30 by screws 30S. The sensor substrate 39 has an annular circuit board and a rotation detection element supported by the circuit board. At least a part of the sensor substrate 39 faces the front end face of the rotor magnet 34. The rotation detection element detects the position of the rotor 27 by detecting the position of the rotor magnet 34.

[0072] The rear shaft portion 33R is rotatably supported by the rear rotor bearing 37. The front shaft portion 33F is rotatably supported by the 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.

[0073] The front end portion of the front shaft portion 33F 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.

[0074] A pinion gear 41 is fixed to the front end portion of the front shaft portion 33F. The pinion gear 41 is connected to at least a part of the speed reduction mechanism portion 7. The rotor shaft 33 is connected to the speed reduction mechanism portion 7 via the pinion gear 41.

[0075] The speed reduction mechanism portion 7 reduces the rotation of the motor 6. The speed reduction mechanism portion 7 connects the front shaft portion 33F of the rotor shaft 33 and the spindle 8. The gears of the speed reduction mechanism portion 7 are driven by the rotor 27. The speed reduction mechanism portion 7 transmits the rotation of the rotor 27 to the spindle 8. The speed reduction mechanism portion 7 rotates the spindle 8 at a rotational speed lower than the rotational speed of the rotor shaft 33. The speed reduction mechanism portion 7 is disposed forward of the stator 26. The speed reduction mechanism portion 7 includes a planetary gear mechanism.

[0076] The speed reduction mechanism unit 7 includes 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. Each of the pinion gear 41, the planetary gears 42, and the internal gear 43 is 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 by the spindle 8 via the pin 42P. The spindle 8 is rotated by the planetary gear 42. The internal gear 43 has internal teeth that mesh with the planetary gears 42.

[0077] 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 with respect to the hammer case 4.

[0078] When the rotor shaft 33 rotates due to the drive of the motor 6, the pinion gear 41 rotates, and the planetary gears 42 revolve around the pinion gear 41. The planetary gears 42 revolve while meshing with the internal teeth of the internal gear 43. Due to the revolution of the planetary gears 42, the spindle 8 connected to the planetary gears 42 via the pins 42P rotates at a rotational speed lower than the rotational speed of the rotor shaft 33.

[0079] 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 rotates by the rotational force of the rotor 27 transmitted through the speed reduction mechanism unit 7. The spindle 8 rotates by the output of the speed reduction mechanism unit 7. The spindle 8 transmits the rotational force of the motor 6 to the anvil 10 via the ball 48 and the hammer 47. At least a part of the spindle 8 is arranged in front of the motor 6. The spindle 8 is arranged in front of the stator 26. At least a part of the spindle 8 is arranged in front of the rotor 27. At least a part of the spindle 8 is arranged in front of the speed reduction mechanism unit 7. At least a part of the spindle 8 is arranged behind the anvil 10.

[0080] 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 recess 8F.

[0081] The spindle shaft portion 8A is a rod shape that is 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 portion of the outer peripheral surface of the spindle shaft portion 8A. The second flange portion 8C is disposed behind the first flange portion 8B. The second flange portion 8C is annular. The connecting portion 8D connects a part of the first flange portion 8B and a part of the second flange portion 8C. The holding portion 8E protrudes rearward from the rear surface of the second flange portion 8C. The holding portion 8E is cylindrical. The spindle recess 8F is provided at the front end portion of the spindle shaft portion 8A. The spindle recess 8F is recessed rearward from the front end surface 8T of the spindle shaft portion 8A. The front end surface 8T of the spindle shaft portion 8A contacts the rear end surface 10T of the anvil 10 in the axial direction. The rear end surface 10T of the anvil 10 is a surface disposed around the anvil convex portion 10D.

[0082] The front end portion of the pin 42P is supported by the first flange portion 8B. The front end portion of the pin 42P is inserted into a hole 8Bh provided in the first flange portion 8B. The rear end portion of the pin 42P is supported by the second flange portion 8C. The rear end portion of the pin 42P is inserted into a hole 8Ch provided in the second flange portion 8C. The planetary gear 42 is disposed 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 the pin 42P.

[0083] The first flange portion 8B, the second flange portion 8C, and the connecting portion 8D constitute a large-diameter columnar portion of the spindle 8. At least two planetary gears 42 are attached to the large-diameter columnar portion of the spindle 8. The spindle shaft portion 8A constitutes a small-diameter columnar portion of the spindle 8. The small-diameter columnar portion of the spindle 8 is provided so as to extend forward from the large-diameter columnar portion of the spindle 8.

[0084] The spindle bearing 44 is disposed radially inside the holding portion 8E. The spindle bearing 44 is held by the holding portion 8E and the bearing box 24.

[0085] The striking mechanism portion 9 is driven by the motor 6. The rotational force of the motor 6 is transmitted to the striking mechanism portion 9 via the speed reduction mechanism portion 7 and the spindle 8. The striking mechanism portion 9 strikes the anvil 10 in the rotational direction based on the rotational force of the spindle 8 that rotates by the motor 6. The striking mechanism portion 9 includes a hammer 47, a ball 48, a coil spring 49, and a washer 50. The striking mechanism portion 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.

[0086] The hammer 47 is disposed forward of the speed reduction mechanism portion 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.

[0087] The hammer 47 has a body portion 47A, an outer cylindrical portion 47B, an inner cylindrical portion 47C, and a hammer projection 47D. The body portion 47A is disposed around the spindle shaft portion 8A. The body portion 47A is annular. Each of the outer cylindrical portion 47B and the inner cylindrical portion 47C projects rearward from the body portion 47A. The outer cylindrical portion 47B is disposed radially outside 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 provided so as to be recessed forward from the rear end portion of the hammer 47. The recess 47E is ring-shaped. The spindle shaft portion 8A is disposed radially inside 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 projection 47D projects forward from the body portion 47A. Two hammer projections 47D are provided.

[0088] The hammer 47 is rotated by the motor 6. The rotational force of the motor 6 is transmitted to the hammer 47 via the speed reduction mechanism section 7 and the spindle 8. The hammer 47 is rotatable 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. The hammer 47 rotates about the rotation axis AX.

[0089] The washer 50 is disposed inside the recess 47E. 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 are disposed between the rear surface of the body portion 47A and the front surface of the washer 50.

[0090] The coil spring 49 is disposed around the spindle shaft portion 8A. The rear end portion of the coil spring 49 is supported by the first flange portion 8B. The front end portion of the coil spring 49 is disposed inside the recess 47E and supported by the washer 50. The coil spring 49 biases the hammer 47 toward the anvil 10 side. That is, the coil spring 49 biases the hammer 47 forward. The coil spring 49 constantly generates an elastic force for moving the hammer 47 forward.

[0091] The ball 48 is made of a metal such as steel. The ball 48 is disposed between the spindle shaft portion 8A and the body portion 47A.

[0092] The spindle shaft portion 8A has a spindle groove 8G in which at least a part of the ball 48 is disposed. The spindle groove 8G is provided in a part of the outer peripheral surface of the spindle shaft portion 8A. The spindle groove 8G is a first cam portion of the spindle 8.

[0093] The hammer 47 has a hammer groove 47G in which at least a part of the ball 48 is disposed. The hammer groove 47G is provided in a part of the inner peripheral surface 47S of the body portion 47A and the inner cylinder portion 47C. The hammer groove 47G is a second cam portion of the hammer 47.

[0094] The ball 48 contacts the spindle groove 8G which is the first cam part and the hammer groove 47G which is the second cam part. Two balls 48 are provided. Two spindle grooves 8G are provided on the outer peripheral surface of the spindle shaft part 8A. Two hammer grooves 47G are provided on the inner peripheral surface 47S of the body part 47A and the inner cylinder part 47C. One ball 48 is arranged between one spindle groove 8G and one hammer groove 47G. The other ball 48 is arranged between the other spindle groove 8G and the other hammer groove 47G. The ball 48 can roll inside the spindle groove 8G and inside the hammer groove 47G respectively. 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 the movable range defined by the spindle groove 8G and the hammer groove 47G. The hammer 47 is driven in the front-rear direction and the rotational direction by the ball 48.

[0095] The anvil 10 is arranged in front of the motor 6. The anvil 10 is the output part of the impact tool 1 that rotates based on the rotational force of the rotor 27. At least a part of the anvil 10 is arranged in front of the spindle 8. At least a part of the anvil 10 is arranged in front of the hammer 47. The anvil 10 is struck in the rotational direction by the hammer 47.

[0096] The anvil 10 has an anvil shaft part 10A, an anvil protrusion part 10B, and an anvil convex part 10D. The anvil shaft part 10A is a rod-shaped that is long in the front-rear direction. The central axis of the anvil shaft part 10A coincides with the rotation axis AX. The anvil protrusion part 10B is provided at the rear end of the anvil shaft part 10A. The anvil protrusion part 10B protrudes radially outward from the rear end of the anvil shaft part 10A. Two anvil protrusion parts 10B are provided. A washer 52 and a spacer 53 are arranged in front of the anvil protrusion part 10B. The washer 52 and the spacer 53 are supported by the rear surface of the connection part 4C. The washer 52 and the spacer 53 suppress the contact between the front surface of the anvil protrusion part 10B and the hammer case 4.

[0097] A tool hole 10C is provided on the front end face of the anvil 10. The tool hole 10C is formed to extend rearward from the front end face of the anvil shaft portion 10A. A tip tool is inserted into the tool hole 10C. The tip tool is attached to the anvil 10.

[0098] The anvil convex portion 10D is provided at the rear end portion of the anvil 10. The anvil convex portion 10D protrudes rearward from the rear end face of the anvil 10. The anvil convex portion 10D fits into the spindle concave portion 8F. The anvil convex portion 10D supports the spindle 8.

[0099] 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 coincide. The anvil 10 rotates about 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 the present embodiment, two anvil bearings 46 are arranged in the front-rear direction. A spacer 53 is disposed behind the rear anvil bearing 46. The spacer 53 is disposed in a groove provided on the inner peripheral surface of the small cylindrical portion 4B. The spacer 53 suppresses the anvil bearing 46 from coming off rearward from the small cylindrical portion 4B. An O-ring 45 is disposed between the anvil bearing 46 and the anvil shaft portion 10A.

[0100] The hammer protrusion 47D can contact the anvil protrusion 10B. With the hammer protrusion 47D and the anvil protrusion 10B in contact, when the motor 6 is driven, the anvil 10 rotates together with the hammer 47 and the spindle 8.

[0101] The anvil 10 is struck in the rotational direction by the hammer 47. For example, in a screwing operation, when the load acting on the anvil 10 increases, there may be a situation where the anvil 10 cannot be rotated only by the load of the coil spring 49. When the anvil 10 cannot be rotated only by the load of the coil spring 49, the rotation of the anvil 10 and the hammer 47 stops. The spindle 8 and the hammer 47 are relatively movable in the axial direction and the circumferential direction via the ball 48. Even when the rotation of the hammer 47 stops, the rotation of the spindle 8 continues by the power generated by the motor 6. When the spindle 8 rotates while the rotation of the hammer 47 has stopped, the ball 48 moves rearward while being guided by the spindle groove 8G and the hammer groove 47G respectively. When the spindle 8 rotates while the rotation of the hammer 47 has stopped, the outer peripheral surface 8S of the spindle 8 and the inner peripheral surface 47S of the hammer 47 slide. The hammer 47 receives a force from the ball 48 and moves rearward along with the ball 48. That is, the hammer 47 moves rearward when the spindle 8 rotates while the rotation of the anvil 10 has stopped. When the hammer 47 moves rearward, the contact between the hammer projection 47D and the anvil projection 10B is released.

[0102] As described above, the coil spring 49 constantly generates an elastic force that moves the hammer 47 forward. The hammer 47 that has moved rearward moves forward by the elastic force of the coil spring 49. When the hammer 47 moves forward, it receives a force in the rotational direction from the ball 48. That is, the hammer 47 moves forward while rotating. When the hammer 47 moves forward while rotating, the hammer 47 contacts the anvil projection 10B while rotating. Thereby, the anvil projection 10B is struck in the rotational direction by the hammer projection 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.

[0103] The tip tool holding portion 11 is disposed around the front portion of the anvil 10. The tip tool holding portion 11 holds a tip tool inserted into the tool hole 10C of the anvil 10. The tip tool held by the tip tool holding portion 11 is detachable.

[0104] The tip tool holding portion 11 includes a ball 71, a leaf spring 72, a sleeve 73, a coil spring 74, and a positioning member 75.

[0105] The anvil 10 has a support recess 76 for supporting the ball 71. The support recess 76 is formed on the outer surface of the anvil shaft portion 10A. In the present embodiment, two support recesses 76 are formed in the anvil shaft portion 10A.

[0106] The ball 71 is movably supported by the anvil 10. The ball 71 is disposed in the support recess 76. One ball 71 is disposed in one support recess 76.

[0107] 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, at least a part of the ball 71 is disposed inside the tool hole 10C. The ball 71 can fix the tip tool inserted into the tool hole 10C. The ball 71 is movable between an engagement position for fixing the tip tool and a release position for releasing the fixing of the tip tool.

[0108] The leaf spring 72 generates an elastic force for moving 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 for moving the ball 71 forward.

[0109] The sleeve 73 is a cylindrical member. The sleeve 73 is disposed around the anvil shaft portion 10A. The sleeve 73 is axially movable around the anvil shaft portion 10A. The sleeve 73 can prevent the ball 71 disposed at the engagement position from escaping from the engagement position. The sleeve 73 can change the ball 71 to a state where it can move from the engagement position to the release position by being axially moved.

[0110] The sleeve 73 is movable around the anvil shaft portion 10A between a blocking position that blocks the radial outward movement of the ball 71 and an allowing position that allows the radial outward movement of the ball 71.

[0111] When the sleeve 73 is disposed at the blocking position, the ball 71 disposed at the engagement position is suppressed from moving radially outward. That is, when the sleeve 73 is disposed at the blocking position, the ball 71 disposed at the engagement position is prevented from escaping from the engagement position. When the sleeve 73 is disposed at the blocking position, the state in which the tip tool is fixed by the ball 71 is maintained.

[0112] When the sleeve 73 is moved to the allowing position, the ball 71 disposed at the engagement position is allowed to move radially outward. The sleeve 73 changes the ball 71 to a state where it can move from the engagement position to the release position by being moved to the allowing position. That is, when the sleeve 73 is disposed at the allowing position, the ball 71 disposed at the engagement position is allowed to escape from the engagement position. When the sleeve 73 is disposed at the allowing position, the state in which the tip tool is fixed by the ball 71 can be released.

[0113] The coil spring 74 generates an elastic force so that the sleeve 73 moves to the blocking position. The coil spring 74 is disposed around the anvil shaft portion 10A. The blocking position is defined to be rearward of the allowing position. The coil spring 74 generates an elastic force that moves the sleeve 73 rearward.

[0114] 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 portion of the sleeve 73. The positioning member 75 positions the sleeve 73 at the blocking position. The sleeve 73, which is applied with an elastic force to move rearward from the coil spring 74, is positioned at the blocking position by contacting the positioning member 75.

[0115] The fan 12 is disposed rearward of the stator 26 of the motor 6. The fan 12 generates an air flow for cooling the motor 6. The fan 12 is fixed to at least a part of the rotor 27. The fan 12 is fixed to the rear shaft portion 33R via the bush 12A. The fan 12 is disposed between the rear rotor bearing 37 and the stator 26. The fan 12 rotates by the rotation of the rotor 27. When the rotor shaft 33 rotates, the fan 12 rotates together with the rotor shaft 33. When the fan 12 rotates, the air in the external space of the housing 2 flows into the internal space of the housing 2 through the intake port 17. The air that has flowed into the internal space of the housing 2 cools the motor 6 by flowing through the internal space of the housing 2. The air that has flowed through the internal space of the housing 2 flows out to the external space of the housing 2 through the exhaust port 18 by the rotation of the fan 12.

[0116] The battery mounting portion 13 is disposed below the battery holding portion 23. The battery mounting portion 13 is connected to the battery pack 25. The battery pack 25 is mounted on the battery mounting portion 13. The battery pack 25 is detachable from the battery mounting portion 13. The battery pack 25 is inserted into the battery mounting portion 13 from the front of the battery holding portion 23 to be mounted on the battery mounting portion 13. The battery pack 25 is removed from the battery mounting portion 13 by being pulled out forward from the battery mounting portion 13. The battery pack 25 includes a secondary battery. In the present embodiment, the battery pack 25 includes a rechargeable lithium-ion battery. By being mounted on the battery mounting portion 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.

[0117] 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. When the trigger lever 14 is operated, the driving and stopping of the motor 6 are switched.

[0118] 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. When the forward / reverse switching lever 15 is operated, the rotation direction of the motor 6 is switched from one of the forward rotation direction and the reverse rotation direction to the other. When the rotation direction of the motor 6 is switched, the rotation direction of the spindle 8 is switched.

[0119] The light assembly 16 emits illumination light. The light assembly 16 illuminates the anvil 10 and the periphery of the anvil 10 with the illumination light. The light assembly 16 illuminates the front of the anvil 10 with the illumination light. Also, the light assembly 16 illuminates the tip tool attached to the anvil 10 and the periphery of the tip tool with the illumination light. In the present embodiment, the light assembly 16 is disposed around the small cylindrical portion 4B. The light assembly 16 includes a circuit board 16A, a light emitting element 16B supported by the circuit board 16A, an optical member 16C through which the light emitted from the light emitting element 16B passes, and a light shielding member 16D disposed around the optical member 16C.

[0120] <Lubricant Supply> The hammer case 4 houses at least a part of the spindle 8. The hammer case 4 houses the hammer 47. The hammer case 4 houses the ball 48. The hammer case 4 houses at least a part of the anvil 10. The hammer case 4 rotatably holds the anvil 10 via the anvil bearing 46. A lubricant is put into the hammer case 4. In the present embodiment, the lubricant is grease.

[0121] A first opening 61 is provided at the front portion of the spindle 8. A second opening 62 is provided at the rear portion of the spindle 8. The first opening 61 is a bottomed hole formed to extend rearward from the front end of the spindle 8. The first opening 61 is formed to extend rearward from the front end face 8T of the spindle shaft portion 8A which is a small diameter cylindrical portion. The second opening 62 is a bottomed hole formed to extend forward from the rear end of the spindle 8. The second opening 62 is formed to extend forward from the rear end face of the second flange portion 8C which is a large diameter cylindrical portion.

[0122] The pinion gear 41 is disposed in the second opening 62. The pinion gear 41 is inserted into the second opening 62 from the rear end portion of the second opening 62.

[0123] A partition wall 60 is provided between the first opening 61 and the second opening 62. The partition wall 60 is provided between the rear end portion 61A of the first opening 61 and the front end portion 62A of the second opening 62. The partition wall 60 exists inside the spindle shaft portion 8A. The rear end portion 61A of the first opening 61 is positioned inside the spindle shaft portion 8A. The front end portion 62A of the second opening 62 is positioned inside the spindle shaft portion 8A. The first opening 61 is formed inside the spindle shaft portion 8A.

[0124] In a plane orthogonal to the rotation axis AX, each of the anvil convex portion 10D, the spindle concave portion 8F, the first opening 61, and the second opening 62 is circular. The rotation axis AX, the central axis of the anvil convex portion 10D, the central axis of the spindle concave portion 8F, the central axis of the first opening 61, and the central axis of the second opening 62 coincide.

[0125] The first opening 61 is provided behind the spindle concave portion 8F. The spindle concave portion 8F is provided at the front end portion of the first opening 61. The first opening 61 communicates with the spindle concave portion 8F. As shown in FIG. 5, the spindle concave portion 8F has an inner peripheral surface 8Fa facing radially inward and a front surface 8Fb connected to the rear end portion of the inner peripheral surface 8Fa and facing forward. The first opening 61 is formed to extend rearward from the front surface 8Fb. Note that the spindle concave portion 8F may be regarded as a part of the first opening 61.

[0126] The diameter D1 of the first opening 61 is smaller than the diameter D8 of the spindle concave portion 8F. The diameter D1 of the first opening 61 is smaller than the diameter D2 of the second opening 62. The diameter D2 of the second opening 62 is smaller than the diameter D8 of the spindle concave portion 8F.

[0127] Grease is inserted into the first opening 61 as a lubricant. Grease is also inserted into the second opening 62.

[0128] The first opening 61 extends at least to the spindle groove 8G which is the first cam portion. The rear end portion 61A of the first opening 61 is disposed rearward of the spindle groove 8G. The rear end portion 61A of the first opening 61 is also disposed forward of the first flange portion 8B.

[0129] The second opening 62 extends at least to the speed reduction mechanism portion 7. The front end portion 62A of the second opening 62 is disposed forward of the speed reduction mechanism portion 7. As shown in FIG. 3, the front end portion 62A of the second opening 62 is disposed forward of the planetary gear 42. The front end portion 62A of the second opening 62 is disposed forward of the pin 42P. The front end portion 62A of the second opening 62 is also disposed forward of the first flange portion 8B.

[0130] As shown in FIG. 3, in the front-rear direction, the dimension L1 of the first opening 61 is larger than the dimension L2 of the second opening 62. In the front-rear direction, the dimension L1 of the first opening 61 is larger than the dimension of the spindle recess 8F.

[0131] The spindle shaft portion 8A has a passage 63 connected to the first opening 61. The first opening 61 includes the passage 63. The passage 63 is formed to extend radially outward from the first opening 61. The passage 63 is formed to extend in a direction orthogonal to the rotation axis AX. The radially inner end portion of the passage 63 is connected to the inner peripheral surface of the first opening 61. The radially outer end portion of the passage 63 is connected to the outer peripheral surface 8S of the spindle shaft portion 8A. The passage 63 is a through hole formed to connect the inner peripheral surface 61S of the first opening 61 and the outer peripheral surface 8S of the spindle shaft portion 8A. The outer end portion of the passage 63 is provided on the outer peripheral surface 8S of the spindle shaft portion 8A.

[0132] The cross-sectional shape of the passage 63 is circular. The diameter of the passage 63 is smaller than the diameter D1 of the first opening 61.

[0133] At least two passages 63 are provided. In the present embodiment, two passages 63 are provided. In the circumferential direction, the two passages 63 are provided at mutually different positions. In the front-rear direction, the two passages 63 are provided at the same position.

[0134] Passage 63 supplies the grease from the first opening 61 between the spindle 8 and the hammer 47. In the present embodiment, passage 63 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. Due to the centrifugal force of the spindle 8, the grease placed in the first opening 61 flows through passage 63 toward the outer peripheral surface 8S of the spindle shaft portion 8A. The grease that has flowed through passage 63 is supplied between the outer peripheral surface 8S of the spindle shaft portion 8A and the inner peripheral surface 47S of the inner cylinder portion 47C.

[0135] When the spindle 8 rotates while the rotation of the hammer 47 has stopped, the outer peripheral surface 8S of the spindle 8 and the inner peripheral surface 47S of the hammer 47 slide. By supplying lubricating oil between the outer peripheral surface 8S and the inner peripheral surface 47S which are sliding surfaces, wear or seizure of the outer peripheral surface 8S and the inner peripheral surface 47S is suppressed.

[0136] As shown in FIG. 5, the grease placed in the first opening 61 is supplied between the spindle 8 and the anvil 10 through the opening 61T provided at the front end portion of the first opening 61. The opening 61T is provided so as to face the anvil convex portion 10D. The opening 61T supplies lubricating oil between the inner surface of the spindle recess 8F and the surface of the anvil convex portion 10D.

[0137] When the spindle 8 rotates while the rotation of the anvil 10 has stopped, the inner surface of the spindle recess 8F and the surface of the anvil convex portion 10D slide. By supplying grease between the inner surface of the spindle recess 8F and the surface of the anvil convex portion 10D which are sliding surfaces, wear or seizure of the inner surface of the spindle recess 8F and the surface of the anvil convex portion 10D is suppressed.

[0138] As shown in FIG. 5, a groove 47R is provided on the inner peripheral surface 47S of the inner cylinder portion 47C of the hammer 47. The groove 47R is formed so as to be recessed radially outward from the inner peripheral surface 47S of the inner cylinder portion 47C. The groove 47R is formed so as to surround the spindle shaft portion 8A. At least a part of the groove 47R is disposed in front of the passage 63. Grease is accommodated in the groove 47R. The grease accommodated in the groove 47R is supplied between the outer peripheral surface 8S of the spindle shaft portion 8A and the inner peripheral surface 47S of the inner cylinder portion 47C.

[0139] <Operation of the impact tool> Next, the operation of the impact tool 1 will be described. For example, when performing a screwing operation on a work target, a tip tool (driver bit) used for the screwing operation is inserted into the tool hole 10C of the anvil 10. The tip tool inserted into the tool hole 10C is held by the tip tool holding portion 11. After the tip tool is attached to the anvil 10, the operator holds 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 activated, and at the same time, the light assembly 16 lights up. When the motor 6 is activated, 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 revolves around the pinion gear 41 while rotating in a state of meshing with the internal teeth of the internal gear 43. The planetary gear 42 is rotatably supported by the spindle 8 via the pin 42P. Due to the revolution of the planetary gear 42, the spindle 8 rotates at a rotational speed lower than the rotational speed of the rotor shaft 33.

[0140] When the spindle 8 rotates in a state where the hammer projection 47D and the anvil projection 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 screwing operation progresses.

[0141] When a load equal to or greater than a predetermined value acts on the anvil 10 due to the progress of the screwing operation, the rotation of the anvil 10 and the hammer 47 stops. When the spindle 8 rotates while the rotation of the hammer 47 has stopped, the hammer 47 moves rearward. When the hammer 47 moves rearward, the contact between the hammer projection 47D and the anvil projection 10B is released. The hammer 47 that has moved rearward moves forward while rotating by the elastic force of the coil spring 49. When 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 about the rotation axis AX with high torque. Therefore, the screw is tightened on the work piece with high torque.

[0142] <Effect> As described above, in the present embodiment, the impact tool 1 includes a motor 6, a speed reduction mechanism unit 7 that reduces the rotation of the motor 6, a spindle 8 that rotates by the output of the speed reduction mechanism unit 7 and has a spindle groove 8G that is a first cam portion, a hammer 47 that is held by the spindle 8 and has a hammer groove 47G that is a second cam portion, a ball 48 that contacts the spindle groove 8G and the hammer groove 47G, an anvil 10 that is struck in the rotational direction by the hammer 47, a hammer case 4 that houses the hammer 47, rotatably holds the anvil 10, and is filled with a lubricant, a tip tool holding portion 11 disposed at the front portion of the anvil 10, and a coil spring 49 that biases the hammer 47 toward the anvil 10. The hammer 47 is driven in the front-rear direction and the rotational direction by the ball 48. A first opening 61 into which a lubricant is filled is provided at the front portion of the spindle 8. A second opening 62 is provided at the rear portion of the spindle 8. A partition wall 60 is provided between the first opening 61 and the second opening 62. The first opening 61 extends at least up to the spindle groove 8G. The second opening 62 extends at least up to the speed reduction mechanism unit 7. An anvil convex portion 10D provided at the rear end portion of the anvil 10 fits into a spindle concave portion 8F provided at the front end portion of the first opening 61 to support the spindle 8.

[0143] In the above configuration, since the grease, which is a lubricant, is put into the first opening 61 provided at the front portion of the spindle 8, leakage to the rear of the spindle 8 is suppressed. Therefore, a decrease in the amount of grease supplied between the spindle 8 and the hammer 47 is suppressed. Accordingly, a decrease in the life of the impact tool 1 is suppressed.

[0144] In the present embodiment, in the front-rear direction parallel to the rotation axis AX of the motor 6, the first opening 61 is provided behind the spindle recess 8F and communicates with the spindle recess 8F.

[0145] In the above configuration, the grease contained in the first opening 61 is supplied to the boundary between the spindle recess 8F of the spindle 8 and the anvil convex portion 10D of the anvil 10. Accordingly, a decrease in the life of the impact tool 1 is suppressed.

[0146] In the present embodiment, in the plane orthogonal to the rotation axis AX of the motor 6, each of the spindle recess 8F and the first opening 61 is circular. The diameter D1 of the first opening 61 is smaller than the diameter D8 of the spindle recess 8F.

[0147] In the above configuration, the grease contained in the first opening 61 is smoothly supplied to the boundary between the spindle recess 8F of the spindle 8 and the anvil convex portion 10D of the anvil 10. Further, since the diameter D8 of the spindle recess 8F is large, the spindle 8 is stably supported by the anvil 10.

[0148] In the present embodiment, in the front-rear direction, the dimension L1 of the first opening 61 is larger than the dimension of the spindle recess 8F.

[0149] In the above configuration, since the dimension L1 of the first opening 61 is large in the front-rear direction, an appropriate amount of grease is put into the first opening 61.

[0150] In the present embodiment, in a plane orthogonal to the rotation axis AX of the motor 6, the second opening 62 is circular. The diameter D1 of the first opening 61 is smaller than the diameter D2 of the second opening 62.

[0151] In the above configuration, since the diameter D1 of the first opening 61 is not excessively large, a decrease in the strength of the spindle 8 is suppressed.

[0152] In the present embodiment, the diameter D2 of the second opening 62 is smaller than the diameter D8 of the spindle recess 8F.

[0153] In the above configuration, since the diameter D2 of the second opening 62 is not excessively large, a decrease in the strength of the spindle 8 is suppressed.

[0154] In the present embodiment, in the front-rear direction, the dimension L1 of the first opening 61 is larger than the dimension L2 of the second opening 62.

[0155] In the above configuration, since the dimension L1 of the first opening 61 is large in the front-rear direction, an appropriate amount of grease can be put into the first opening 61.

[0156] In the present embodiment, the rotation axis AX of the motor 6, the central axis of the spindle recess 8F, the central axis of the first opening 61, and the central axis of the second opening 62 coincide.

[0157] In the above configuration, eccentricity of the spindle 8 is suppressed.

[0158] In the present embodiment, the spindle 8 includes a first flange portion 8B and a second flange portion 8C which are large-diameter columnar portions to which at least two planetary gears 42 are attached, and a spindle shaft portion 8A which is a small-diameter columnar portion extending forward from the large-diameter columnar portion. The first opening 61 is formed inside the spindle shaft portion 8A.

[0159] In the above configuration, since the first opening 61 is provided inside the spindle shaft portion 8A, grease is smoothly supplied between the spindle 8 and the hammer 47 and between the spindle 8 and the anvil 10, respectively.

[0160] In the present embodiment, the spindle shaft portion 8A has a passage 63 that connects the inner peripheral surface 61S of the first opening 61 and the outer peripheral surface 8S of the spindle shaft portion 8A.

[0161] In the above configuration, due to the centrifugal force when the spindle 8 rotates, the grease placed in the first opening 61 is supplied to the outer peripheral surface 8S of the spindle shaft portion 8A through the passage 63.

[0162] In the present embodiment, the cross-sectional shape of the passage 63 is circular. The diameter of the passage 63 is smaller than the diameter D1 of the first opening 61.

[0163] In the above configuration, since the diameter of the passage 63 is small, an appropriate amount of grease is supplied from the first opening 61 to the outer peripheral surface 8S of the spindle shaft portion 8A.

[0164] In the present embodiment, the passage 63 is formed to extend in a direction perpendicular to the rotation axis AX of the motor 6.

[0165] In the above configuration, due to the centrifugal force when the spindle 8 rotates, the grease placed in the first opening 61 is smoothly supplied to the outer peripheral surface 8S of the spindle shaft portion 8A through the passage 63.

[0166] In the present embodiment, at least two passages 63 are provided. In the circumferential direction of the rotation axis AX of the motor 6, the two passages 63 are provided at mutually different positions. In the front-rear direction parallel to the rotation axis AX of the motor 6, the two passages 63 are provided at the same position.

[0167] In the above configuration, when the spindle 8 rotates, the grease placed in the first opening 61 is smoothly supplied to the outer peripheral surface 8S of the spindle shaft portion 8A through the passage 63 by the centrifugal force.

[0168] [Second Embodiment] The second embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description of those components is simplified or omitted.

[0169] FIG. 8 is a longitudinal sectional view showing a part of the impact tool 1 according to the present embodiment. In the present embodiment, the impact tool 1 includes a lid 64 disposed in the first opening 61. The lid 64 is inserted inside the first opening 61 through the spindle recess 8F. After the lid 64 is inserted into the first opening 61, the anvil convex portion 10D is inserted into the spindle recess 8F.

[0170] The lid 64 is substantially columnar. The outer peripheral surface of the lid 64 contacts the inner peripheral surface 61S of the first opening 61. The lid 64 is disposed so as to close the opening 61T at the front end portion of the first opening 61. In the present embodiment, the lid 64 is disposed at an intermediate portion of the first opening 61 in the front-rear direction. The lid 64 is disposed in front of the rear end portion 61A of the first opening 61. The lid 64 is disposed in front of the passage 63.

[0171] The lid 64 may be made of metal, synthetic resin, or rubber. In the present embodiment, the lid 64 is made of felt. As the felt, wool felt is exemplified. Before the lid 64 is inserted into the first opening 61, the outer diameter of the lid 64 is larger than the inner diameter of the first opening 61. The felt lid 64 is deformable. The lid 64 is inserted into the first opening 61 while being crushed. By inserting the lid 64 having an outer diameter larger than the inner diameter of the first opening 61 into the first opening 61 while being crushed, the outer peripheral surface of the lid 64 is in close contact with the inner peripheral surface 61S of the first opening 61.

[0172] Similar to the above-described embodiment, grease is put into the first opening 61. The grease is accommodated in each of the first opening 61 behind the lid 64 and the first opening 61 in front of the lid 64. That is, the grease is accommodated between the lid 64 and the rear end portion 61A of the first opening 61, and between the lid 64 and the anvil convex portion 10D, respectively. Similar to the above-described embodiment, the front end surface 8T of the spindle shaft portion 8A is in axial contact with the rear end surface 10T of the anvil 10.

[0173] As described above, in the present embodiment, the impact tool 1 includes a lid 64 that is inserted into the first opening 61 via the spindle recess 8F. The lid 64 is disposed in front of the rear end portion 61A of the first opening 61.

[0174] In the above configuration, it is suppressed that the grease placed between the lid 64 and the rear end portion 61A of the first opening 61 is supplied between the spindle 8 and the anvil 10, and the amount of grease supplied between the spindle 8 and the hammer 47 increases.

[0175] In the present embodiment, the lid 64 is disposed in front of the passage 63.

[0176] In the above configuration, it is suppressed that the grease placed between the lid 64 and the rear end portion 61A of the first opening 61 is supplied between the spindle 8 and the anvil 10, and the amount of grease supplied between the spindle 8 and the hammer 47 increases.

[0177] In the present embodiment, the lid 64 is made of felt.

[0178] In the above configuration, the deterioration of workability when inserting the lid 64 into the first opening 61 is suppressed. Since the felt is deformable, an assembler of the impact tool 1 can insert the lid 64 into the first opening 61 with good workability by inserting it into the first opening 61 while crushing the felt. Further, as the felt having an outer diameter larger than the inner diameter of the first opening 61 is inserted into the first opening 61 while being crushed, the outer peripheral surface of the felt comes into close contact with the inner peripheral surface 61S of the first opening 61. Therefore, since the sealing performance between the outer peripheral surface of the felt and the inner peripheral surface 61S of the first opening 61 is improved, leakage of the lubricating oil accommodated in the first opening 61 through the opening at the front end of the first opening 61 is effectively suppressed.

[0179] [Third Embodiment] The third embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiments are denoted by the same reference numerals, and the description of those components is simplified or omitted.

[0180] FIG. 9 is a longitudinal sectional view showing a part of the impact tool 1 according to the present embodiment. In the present embodiment, the impact tool 1 includes a seal member 65 that seals the boundary between the spindle recess 8F and the anvil projection 10D. The seal member 65 is ring-shaped. The seal member 65 is arranged so as to surround the anvil projection 10D. The seal member 65 is an O-ring. Note that the seal member 65 may be a lip seal.

[0181] A groove 8H is provided at the front end of the inner peripheral surface 8Fa of the spindle recess 8F. The groove 8H is provided so as to surround the anvil projection 10D. The seal member 65 is arranged in the groove 8H. Similar to the above-described embodiment, the front end surface 8T of the spindle shaft portion 8A contacts the rear end surface 10T of the anvil 10 in the axial direction.

[0182] As described above, in the present embodiment, the impact tool 1 includes a seal member 65 that is arranged so as to surround the anvil projection 10D and seals the boundary between the spindle recess 8F and the anvil projection 10D.

[0183] In the above configuration, it is possible to suppress grease supplied from the first opening 61 between the spindle recess 8F and the anvil projection 10D from leaking outside the boundary between the spindle recess 8F and the anvil projection 10D.

[0184] [Fourth Embodiment] The fourth embodiment will be described. In the following description, the same reference numerals are given to components that are the same as or equivalent to those in the above-described embodiments, and the description of those components will be simplified or omitted.

[0185] FIG. 10 is a longitudinal sectional view showing a part of the impact tool 1 according to the present embodiment. As shown in FIG. 10, the passage 63 may not be provided in the spindle shaft portion 8A. Since the passage 63 is not provided, the grease put into the first opening 61 is sufficiently supplied to the boundary between the spindle recess 8F and the anvil projection 10D through the opening 61T at the front end portion of the first opening 61. Similar to the above-described embodiment, the front end surface 8T of the spindle shaft portion 8A is in axial contact with the rear end surface 10T of the anvil 10.

[0186] [Fifth Embodiment] The fifth embodiment will be described. In the following description, the same reference numerals are given to components that are the same as or equivalent to those in the above-described embodiments, and the description of those components will be simplified or omitted.

[0187] FIG. 11 is a longitudinal sectional view showing a part of the impact tool 1 according to the present embodiment. In the present embodiment, a grease groove 8J is provided on the front end surface of the spindle shaft portion 8A. A grease groove 10J is provided on the outer peripheral surface of the anvil projection 10D. The front end surface 8T of the spindle shaft portion 8A faces the rear end surface 10T of the anvil 10. The outer peripheral surface of the anvil projection 10D faces the inner peripheral surface 8Fa of the spindle recess 8F. The grease is accommodated in each of the grease groove 8J and the grease groove 10J.

[0188] The grease groove 8J is formed in an annular shape so as to surround the rotation axis AX. The grease groove 8J may be a single annular shape or a double annular shape. The grease groove 8J may be a spiral shape.

[0189] The grease groove 10J is formed in an annular shape so as to surround the rotation axis AX. The grease groove 10J may be single-annular or double-annular. The grease groove 10J may be spiral.

[0190] In addition, a grease groove may be provided on the rear end face of the anvil 10 facing the front end face of the spindle shaft portion 8A. A grease groove may be provided on the inner peripheral surface 8Fa of the spindle concave portion 8F facing the outer peripheral surface of the anvil convex portion 10D.

[0191] As described above, in the present embodiment, a grease groove is provided on either the front end face 8T of the spindle 8 or the rear end face 10T of the anvil 10 that contacts the front end face 8T.

[0192] In the above configuration, since grease is held in the grease groove, the lubricity between the spindle 8 and the anvil 10 is improved.

[0193] [Sixth Embodiment] The sixth embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiments are denoted by the same reference numerals, and the description of those components is simplified or omitted.

[0194] FIG. 12 is a longitudinal sectional view showing the upper part of the impact tool 1 according to the present embodiment. As shown in FIG. 12, an anvil concave portion 10E may be provided so as to be recessed forward from the rear end face 10U of the anvil 10, and a spindle convex portion 8K may be provided at the front end portion of the spindle 8. The spindle convex portion 8K fits into the anvil concave portion 10E. The spindle convex portion 8K is inserted into the anvil concave portion 10E from the rear of the anvil concave portion 10E. The opening at the front end portion of the first opening 61 is disposed on the front end face of the spindle convex portion 8K. The front end face 8U of the spindle shaft portion 8A is in axial contact with the rear end face 10U of the anvil 10. The front end face 8U of the spindle shaft portion 8A is a surface disposed around the spindle convex portion 8K.

[0195] [Seventh Embodiment] A seventh embodiment will be described. In the following description, components that are the same as or equivalent to those in the above-described embodiments are denoted by the same reference numerals, and the description of those components will be simplified or omitted.

[0196] FIG. 13 is a longitudinal sectional view showing a part of the impact tool 1 according to the present embodiment. The impact tool 1 according to the present embodiment is a modification of the impact tool according to the above-described sixth embodiment. As shown in FIG. 13, a grease groove 8M may be provided on the outer peripheral surface of the spindle convex portion 8K facing the inner peripheral surface of the anvil recess 10E. A grease groove 8L may be provided on the front end surface 8U of the spindle shaft portion 8A facing the rear end surface 10U of the anvil 10.

[0197] Note that a grease groove may be provided on the inner peripheral surface of the anvil recess 10E facing the outer peripheral surface of the spindle convex portion 8K. A grease groove may be provided on the rear end surface of the anvil 10 facing the opposing surface of the spindle shaft portion 8A.

[0198] [Another Embodiment] In the above-described embodiment, the impact tool 1 is an impact driver. The impact tool 1 may be an impact wrench having a tip tool holding portion with a square shape and capable of housing a socket.

[0199] In the above-described embodiment, the power source of the impact tool 1 does not have to be the battery pack 25, and may be a commercial power source (AC power source). [Description of Reference Numerals]

[0200] 1... Impact tool, 2... Housing, 2L... Left housing, 2R... Right housing, 2S... Screw, 3... Rear cover, 3S... Screw, 4... Hammer case, 4A... Large cylindrical part, 4B... Small cylindrical part, 4C... Connecting part, 5... Hammer case cover, 6... Motor, 7... Reduction mechanism part, 8... Spindle, 8A... Spindle shaft part (small-diameter cylindrical part), 8B... First flange part (large-diameter cylindrical part), 8Bh... Hole, 8C... Second flange part (large-diameter cylindrical part), 8Ch... Hole, 8D... Connecting part (large-diameter cylindrical part), 8E... Holding part, 8F... Spindle recess, 8Fa... Inner peripheral surface, 8Fb... Front surface, 8G... Spindle groove (first cam part), 8H... Groove, 8J... Grease groove, 8K... Spindle protrusion, 8L... Grease groove, 8M... Grease groove, 8S... Outer peripheral surface, 8T... Front end surface, 8U... Front end surface, 9... Striking mechanism part, 10... Anvil, 10A... Anvil shaft part, 10B... Anvil protrusion, 10C... Tool hole, 10D... Anvil protrusion, 10E... Anvil recess, 10J... Grease groove, 10T... Rear end surface, 10U... Rear end surface, 11... Tip tool holding part, 12... Fan, 12A... Bush, 13... Battery mounting part, 14... Trigger lever, 15... Forward and reverse switching lever, 16... Light assembly, 16A... Circuit board, 16B... Light-emitting element, 16C... Optical member, 16D... Light-shielding member, 17... Air inlet, 18... 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... Connecting part, 25... Battery pack, 26... Stator, 27... Rotor, 28... Stator core, 29... Rear insulator, 30... Front insulator, 30S... Screw, 31... Coil, 32... Rotor core, 33... Rotor shaft, 33F... Front shaft part, 33R... Rear shaft part, 34... Rotor magnet, 35... Sensor magnet, 36... Fusing terminal, 37... Rear rotor bearing, 38... Front rotor bearing, 39... Sensor board, 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 part, 47C... Inner cylinder part, 47D... Hammer protrusion, 47E... Recess, 47G... Hammer groove (second cam part), 47R... Groove, 47S... Inner peripheral surface, 48... Ball, 49... Coil spring, 50... Washer, 51... Ball, 52... Washer,53... spacer, 60... partition wall, 61... first opening, 61A... rear end portion, 61S... inner peripheral surface, 61T... opening, 62... second opening, 62A... front end portion, 63... passage, 64... lid, 65... seal member, 71... ball, 72... leaf spring, 73... sleeve, 74... coil spring, 75... positioning member, 76... support recess, AX... rotation axis.,

Claims

1. A motor, A speed reduction mechanism unit that reduces the rotation of the motor, A spindle that rotates by the output of the speed reduction mechanism unit and has a first cam portion, A hammer that is held by the spindle and has a second cam portion, A ball that contacts the first cam portion and the second cam portion, An anvil that is struck in the rotational direction by the hammer, A hammer case that houses the hammer, rotatably holds the anvil, and contains a lubricant, A tip tool holding portion disposed on the anvil, A coil spring that biases the hammer toward the anvil side, and is provided with, The hammer is driven in the front-rear direction and the rotational direction by the ball, A first opening through which a lubricant is introduced is provided at the front portion of the spindle, a second opening is provided at the rear portion of the spindle, and a partition wall is provided between the first opening and the second opening, The first opening extends at least to the first cam portion, The second opening extends at least to the speed reduction mechanism unit, A convex portion provided at the rear end portion of the anvil fits into a concave portion provided at the front end portion of the first opening to support the spindle, An impact tool.

2. In the front-rear direction parallel to the rotation axis of the motor, the first opening is provided behind the concave portion and communicates with the concave portion, The impact tool according to claim 1.

3. In a plane orthogonal to the rotation axis of the motor, each of the concave portion and the first opening is circular, The diameter of the first opening is smaller than the diameter of the concave portion, The impact tool according to claim 2.

4. In the front-rear direction, the dimension of the first opening is larger than the dimension of the concave portion. The impact tool according to claim 3.

5. In a plane orthogonal to the rotation axis of the motor, the second opening is circular. The diameter of the first opening is smaller than the diameter of the second opening. The impact tool according to claim 4.

6. The diameter of the second opening is smaller than the diameter of the concave portion. The impact tool according to claim 5.

7. In the front-rear direction, the dimension of the first opening is larger than the dimension of the second opening. The impact tool according to claim 6.

8. The rotation axis of the motor, the central axis of the concave portion, the central axis of the first opening, and the central axis of the second opening coincide. The impact tool according to claim 7.

9. The spindle has a large-diameter cylindrical portion to which at least two gears are attached, and a small-diameter cylindrical portion extending forward from the large-diameter cylindrical portion. The first opening is formed inside the small-diameter cylindrical portion. The impact tool according to claim 2.

10. The small-diameter cylindrical portion has a passage connecting the inner peripheral surface of the first opening and the outer peripheral surface of the small-diameter cylindrical portion. The impact tool according to claim 9.

11. The cross-sectional shape of the passage is circular. The diameter of the passage is smaller than the diameter of the first opening. The impact tool according to claim 10.

12. The passage is formed to extend in a direction orthogonal to the rotation axis of the motor. The impact tool according to claim 11.

13. At least two of the passages are provided, In the circumferential direction of the rotation axis of the motor, the two passages are provided at mutually different positions, In the front-rear direction parallel to the rotation axis of the motor, the two passages are provided at the same position, The impact tool according to claim 12.

14. It includes a lid inserted into the first opening through the recess, The lid is arranged in front of the rear end portion of the first opening, The impact tool according to claim 2.

15. It includes a lid inserted into the first opening through the recess, The lid is arranged in front of the passage, The impact tool according to claim 10.

16. The lid is made of felt, The impact tool according to claim 14 or claim 15.

17. It includes a seal member arranged to surround the convex portion and sealing the boundary between the concave portion and the convex portion, The impact tool according to claim 1.

18. A grease groove is provided in either one of the front end face of the spindle and the rear end face of the anvil that contacts the front end face, The impact tool according to claim 1.

19. A motor, A speed reduction mechanism portion that reduces the rotation of the motor, A spindle that rotates by the output of the speed reduction mechanism portion and has a first cam portion, A hammer that is held by the spindle and has a second cam portion, A ball that contacts the first cam portion and the second cam portion, An anvil that is struck in the rotational direction by the hammer, A hammer case that houses the hammer, rotatably holds the anvil, and contains a lubricant, A tip tool holding portion disposed on the anvil, A coil spring that biases the hammer toward the anvil side, and is provided with, The hammer is driven in the front-rear direction and the rotational direction by the ball, A first opening for containing a lubricant is provided at the front part of the spindle, and a second opening is provided at the rear part of the spindle, The second opening extends at least to the speed reduction mechanism portion, A grease groove is provided in either the front end face of the spindle or the rear end face of the anvil that contacts the front end face, Impact tool.

20. A spindle used for an impact tool, A large-diameter columnar portion to which at least two gears are attached, A small-diameter columnar portion extending forward from the large-diameter columnar portion, and includes, A first cam portion is provided on the small-diameter columnar portion, A first opening is provided so as to extend rearward from the front end face of the small-diameter columnar portion, A second opening is provided so as to extend forward from the rear end face of the large-diameter columnar portion, The first opening extends at least to the first cam portion, A partition wall is provided between the first opening and the second opening, A concave portion into which a convex portion provided at the rear end portion of the anvil fits is provided at the front end portion of the first opening, Spindle.

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