Impact tools

Abstract

To provide an impact tool that can perform work smoothly even in a narrow place.SOLUTION: An impact tool is provided with: a motor that has a stator and a rotor at least a portion of which is arranged inside the stator and which rotates with a rotating shaft as a center; a spindle, arranged closer to a front side than the stator, which is rotated by rotation force of the rotor; an anvil, at least a portion of which is arranged closer to the front side than the spindle, to which a bit is attached; a hammer that hammers the anvil in a rotation direction; and a housing having a motor storage part that stores the motor. Maximum fastening torque is 140 Nm or more, and a whole length La representing a distance between a rear end portion of the motor storage part and a front end portion of the anvil in a longitudinal direction which is parallel to the rotation shaft is 100 mm or less. A center height Hc representing a distance between the rotating shaft and an upper end portion of the motor storage part in a vertical direction is 29 mm or less.SELECTED DRAWING: Figure 18

Description

Technical Field

[0006] , , ,

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

Background Art

[0002] In the technical field related to impact tools, an impact tool as disclosed in Patent Document 1 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Impact tools may be used in narrow spaces close to walls when tightening screws. Even in narrow spaces, a technology that enables smooth operation using an impact tool is required.

[0005] The technology disclosed in this specification aims to provide an impact tool that can operate smoothly even in narrow spaces.

Means for Solving the Problems

[0006] This specification discloses an impact tool. The impact tool may include a motor having a stator and a rotor, at least part of which is located inside the stator and rotates around a rotation axis; a spindle, located in front of the stator and rotated by the rotational force of the rotor; an anvil, at least part of which is located in front of the spindle and on which a bit is mounted; a hammer for striking the anvil in the rotational direction; and a housing having a motor housing for housing the motor. The maximum tightening torque may be 140 Nm or more. The overall length La, which indicates the distance between the rear end of the motor housing and the front end of the anvil in the front-rear direction parallel to the rotation axis, may be 100 mm or less. The center height Hc, which indicates the distance between the rotation axis and the upper end of the motor housing in the vertical direction, may be 29 mm or less. [Effects of the Invention]

[0007] The technology disclosed herein provides an impact tool that can operate smoothly even in confined spaces. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a front perspective view showing the impact tool according to this embodiment. [Figure 2] Figure 2 is a rear perspective view showing the impact tool according to this embodiment. [Figure 3] Figure 3 is a side view showing the impact tool according to this embodiment. [Figure 4] Figure 4 is a front view showing an impact tool according to this embodiment. [Figure 5] Figure 5 is a longitudinal cross-sectional view showing an impact tool according to this embodiment. [Figure 6] Figure 6 is a longitudinal cross-sectional view showing the upper part of the impact tool according to this embodiment. [Figure 7] Figure 7 is a cross-sectional view showing the upper part of the impact tool according to this embodiment. [Figure 8] Figure 8 is an exploded front perspective view showing a part of the impact tool according to this embodiment. [Figure 9] Figure 9 is an exploded rear perspective view showing a part of the impact tool according to this embodiment. [Figure 10] Figure 10 is a front perspective view showing the hammer according to this embodiment. [Figure 11] Figure 11 is a view of the hammer according to this embodiment, seen from the front. [Figure 12] Figure 12 is a rear perspective view showing the hammer according to this embodiment. [Figure 13] Figure 13 is a longitudinal cross-sectional view showing the hammer according to this embodiment. [Figure 14] Figure 14 is a cross-sectional view showing the hammer according to this embodiment. [Figure 15] Figure 15 is a front perspective view showing a cup washer according to this embodiment. [Figure 16] Figure 16 shows the specifications of an impact tool according to an embodiment and an impact tool according to a comparative example. [Figure 17] Figure 17 shows the corner driving angle of the impact tool according to the embodiment and the impact tool according to the comparative example. [Figure 18] Figure 18 is a diagram illustrating the corner driving conditions for impact tools. [Figure 19] Figure 19 is a diagram illustrating the corner driving conditions for impact tools. [Figure 20] Figure 20 is a diagram illustrating the corner driving conditions for impact tools. [Modes for carrying out the invention]

[0009] In one or more embodiments, the impact tool may include a motor having a stator and a rotor, at least part of which is located inside the stator and rotates around a rotation axis; a spindle, located in front of the stator and rotated by the rotational force of the rotor; an anvil, at least part of which is located in front of the spindle and on which a bit is mounted; a hammer for striking the anvil in the rotational direction; and a housing having a motor housing for housing the motor.

[0010] The maximum tightening torque may be 140 Nm or more.

[0011] The overall length La indicating the distance between the rear end of the motor housing part and the front end of the anvil in the front-rear direction parallel to the rotation axis may be 100 mm or less.

[0012] The center height Hc indicating the distance between the rotation axis and the upper end of the motor housing part in the up-down direction may be 29 mm or less.

[0013] The total overall length Lh indicating the distance between the rear end of the motor housing part and the front end of the bit attached to the anvil in the front-rear direction may be 140 mm or less.

[0014] The corner hitting angle θ indicating the angle formed by the rotation axis and the floor surface when tightening a screw located 10 mm above the floor surface on a wall surface perpendicular to the floor surface with a bit may be 12 degrees or less.

[0015] The head part width Wa indicating the dimension of the motor housing part in the left-right direction may be 65 mm or less.

[0016] The ratio [Wa / La] of the head part width Wa to the overall length La may be 0.6 or less.

[0017] In the above configuration, even in a narrow part or a corner part, an operator can smoothly perform the work using the impact tool.

[0018] <​​​​In this embodiment, the direction parallel to the rotation axis AX of the motor 6 is appropriately referred to as the axial direction, the direction that circles around the rotation axis AX is appropriately referred to as the circumferential direction or rotational direction, and the radial direction of the rotation axis AX is appropriately referred to as the radial direction.

[0020] The rotation axis AX extends in the front-rear direction. One side in the axial direction is forward, and the other side in the axial direction is backward. Furthermore, in the radial direction, the position close to or approaching the rotation axis AX is appropriately referred to as the radially inward direction, and the position far from or away from the rotation axis AX is appropriately referred to as the radially outward direction.

[0021] [Impact Tools] Figure 1 is a front perspective view showing the impact tool 1 according to this embodiment. Figure 2 is a rear perspective view showing the impact tool 1 according to this embodiment. Figure 3 is a side view showing the impact tool 1 according to this embodiment. Figure 4 is a front view showing the impact tool 1 according to this embodiment. Figure 5 is a longitudinal cross-sectional view showing the impact tool 1 according to this embodiment.

[0022] In this embodiment, the impact tool 1 is an impact driver, which is a type of impact tool 1. The impact tool 1 can perform tasks such as tightening screws. The impact tool 1 comprises a housing 2, a hammer case 4, a hammer case cover 5A, a bumper 5B, a housing cover 5C, a motor 6, a reduction mechanism 7, a spindle 8, a striking mechanism 9, an anvil 10, a bit holding mechanism 11, a fan 12, a battery mounting section 13, a trigger 14, a forward / reverse switch 15, an operation display section 16, a light 17, and a controller 18.

[0023] Housing 2 is made of synthetic resin. In this embodiment, housing 2 is made of nylon. 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 fastened together by a plurality of screws 2S. Housing 2 is composed of a pair of split housings.

[0024] The housing 2 includes a motor housing section 21, a grip section 22, and a battery holding section 23.

[0025] The motor housing 21 houses the motor 6. The motor housing 21 has a cylindrical portion 21A and a rear plate portion 21B that is integrally connected to the rear end of the cylindrical portion 21A. The motor housing 21 houses at least a portion of the hammer case 4.

[0026] The grip portion 22 is held by the operator. The grip portion 22 extends downward from the motor housing portion 21. The trigger 14 is located on the upper front part of the grip portion 22.

[0027] The battery holder 23 holds the battery pack 25 via the battery mounting section 13. The battery holder 23 is connected to the lower end of the grip section 22. In both the front-to-back and left-to-right directions, the external dimensions of the battery holder 23 are larger than the external dimensions of the grip section 22.

[0028] The motor housing 21 has an air intake port 19 and an exhaust port 20. The exhaust port 20 is located behind the air intake port 19. 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 into the external space of the housing 2 through the exhaust port 20.

[0029] The hammer case 4 houses the reduction mechanism 7, the spindle 8, the striking mechanism 9, and at least a portion of the anvil 10. At least a portion of the reduction mechanism 7 is located inside the bearing box 24. The reduction mechanism 7 includes a plurality of gears.

[0030] The hammer case 4 is made of metal. In this embodiment, the hammer case 4 is made of aluminum. The hammer case 4 is cylindrical. The hammer case 4 is connected to the front of the motor housing 21. A bearing box 24 is fixed to the rear of the hammer case 4. A cylindrical outer surface is formed on the outer circumference of the bearing box 24. A cylindrical inner surface is formed on the inner circumference of the hammer case 4. The bearing box 24 is fitted into the rear of the hammer case 4 via an O-ring 24A. The bearing box 24 and the hammer case 4 are fixed together by the coupling of the cylindrical outer surface of the bearing box 24 and the cylindrical inner surface of the hammer case 4 via the O-ring 24A. The hammer case 4 is sandwiched between the left housing 2L and the right housing 2R. At least a portion of the hammer case 4 is housed in the motor housing 21. The bearing box 24 is fixed to the motor housing 21 and the hammer case 4, respectively.

[0031] The hammer case cover 5A covers at least a portion of the surface of the hammer case 4. The bumper 5B is fitted to the front end of the hammer case 4. The hammer case cover 5A and bumper 5B protect the hammer case 4. The hammer case cover 5A and bumper 5B prevent contact between the hammer case 4 and objects around it. The housing cover 5C covers at least a portion of the surface of the housing 2.

[0032] Motor 6 is the power source for impact tool 1. Motor 6 is an inner rotor type brushless motor. Motor 6 has a stator 26 and a rotor 27. The stator 26 is supported by a motor housing 21. At least a portion of the rotor 27 is positioned inside the stator 26. The rotor 27 rotates relative to the stator 26. The rotor 27 rotates around a rotation axis AX that extends in the front-rear direction.

[0033] The reduction gear 7 connects the rotor 27 and the spindle 8. The reduction gear 7 transmits the rotation of the rotor 27 to the spindle 8. The reduction gear 7 rotates the spindle 8 at a rotational speed lower than the rotational speed of the rotor 27. The reduction gear 7 is positioned in front of the motor 6. The reduction gear 7 includes a planetary gear mechanism. The reduction gear 7 has multiple gears. The gears of the reduction gear 7 are driven by the rotor 27.

[0034] The spindle 8 rotates due to the rotational force of the rotor 27 transmitted by the reduction mechanism 7. The spindle 8 is positioned in front of at least a portion of the motor 6. The spindle 8 is positioned in front of the stator 26. At least a portion of the spindle 8 is positioned in front of the rotor 27. At least a portion of the spindle 8 is positioned in front of the reduction mechanism 7. The spindle 8 is positioned behind the anvil 10.

[0035] The striking mechanism 9 strikes the anvil 10 in the rotational direction based on the rotational force of the spindle 8, which is rotated by the motor 6. The rotational force of the motor 6 is transmitted to the striking mechanism 9 via the reduction mechanism 7 and the spindle 8.

[0036] The anvil 10 is the output shaft of the impact tool 1, which rotates based on the rotational force of the rotor 27. The anvil 10 is positioned in front of the motor 6. At least a portion of the anvil 10 is positioned in front of the spindle 8. The anvil 10 has a hexagonal bit hole 10A into which a driver bit (bit) is inserted. The hexagonal bit hole 10A is located at the front end of the anvil 10. The driver bit is mounted on the anvil 10.

[0037] The bit holding mechanism 11 holds the driver bit inserted into the hexagonal bit hole 10A of the anvil 10. The bit holding mechanism 11 is positioned around the front of the anvil 10. The bit holding mechanism 11 allows the driver bit to be attached and detached.

[0038] The fan 12 generates an airflow to cool the motor 6. The fan 12 is positioned behind the stator 26 of the motor 6. The fan 12 is fixed to at least a portion of the rotor 27. 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 intake port 19. The air that flows into the internal space of the housing 2 cools the motor 6 by circulating through the internal space of the housing 2. As the fan 12 rotates, the air that has circulated through the internal space of the housing 2 flows out into the external space of the housing 2 through the exhaust port 20.

[0039] The battery mounting section 13 is connected to the battery pack 25. The battery pack 25 is mounted in the battery mounting section 13. The battery pack 25 is detachable from the battery mounting section 13. The battery mounting section 13 is located below the battery holder 23. The battery pack 25 is mounted in the battery mounting section 13 by being inserted into the battery mounting section 13 from the front of the battery holder 23. The battery pack 25 is removed from the battery mounting section 13 by being pulled forward from the battery mounting section 13 while the release button 25A is pressed down. The battery pack 25 includes a secondary battery. In an embodiment, the battery pack 25 includes a rechargeable lithium-ion battery. By being mounted in the battery mounting 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.

[0040] The trigger 14 is operated by the operator to start the motor 6. Operating the trigger 14 switches between driving and stopping the motor 6. The trigger 14 is located on the grip portion 22.

[0041] The forward / reverse rotation switch 15 is operated by the operator. By operating the forward / reverse rotation switch 15 left or right, the rotation direction of the motor 6 is switched from one direction to the other. By switching the rotation direction of the motor 6, the rotation direction of the spindle 8 is switched. The forward / reverse rotation switch 15 is located on the upper part of the grip portion 22.

[0042] The operation display unit 16 has a first operation button 16A and a second operation button 16B. When the operator operates the first operation button 16A, the operating mode of the motor 6 is switched. The operation display unit 16 is provided on the battery holder 23. The operation display unit 16 is provided on the upper surface of the battery holder 23, forward of the grip 22. When the second operation button 16B is operated, the light 17 is turned on or off.

[0043] Light 17 emits illumination light. Light 17 illuminates the anvil 10 and its surroundings with illumination light. Light 17 illuminates the area in front of the anvil 10 with illumination light. Light 17 also illuminates the driver bit attached to the anvil 10 and its surroundings with illumination light. Light 17 is positioned above the trigger 14.

[0044] The controller 18 outputs control signals for controlling the motor 6. The controller 18 includes a circuit board on which multiple electronic components are mounted. Examples of electronic components mounted on the circuit board include a processor such as a CPU (Central Processing Unit), non-volatile memory such as ROM (Read Only Memory) or storage, volatile memory such as RAM (Random Access Memory), transistors, and resistors. The controller 18 is housed in the battery holder 23.

[0045] Figure 6 is a longitudinal cross-sectional view showing the upper part of the impact tool 1 according to this embodiment. Figure 7 is a transverse cross-sectional view showing the upper part of the impact tool 1 according to this embodiment. Figure 8 is an exploded perspective view from the front showing a part of the impact tool 1 according to this embodiment. Figure 9 is an exploded perspective view from the rear showing a part of the impact tool 1 according to this embodiment.

[0046] The hammer case 4 has a first cylindrical portion 401, a second cylindrical portion 402, and a case connecting portion 403. The first cylindrical portion 401 is arranged around the striking mechanism 9. The second cylindrical portion 402 is positioned in front of the first cylindrical portion 401. The outer diameter of the second cylindrical portion 402 is smaller than the outer diameter of the first cylindrical portion 401. The case connecting portion 403 is positioned to connect the front end of the first cylindrical portion 401 and the outer circumferential surface of the second cylindrical portion 402. The rear end of the second cylindrical portion 402 protrudes rearward from the case connecting portion 403.

[0047] The motor 6 has a stator 26 and a rotor 27. The stator 26 has a stator core 28, a front insulator 29, a rear insulator 30, and a coil 31. The rotor 27 rotates around a rotation axis AX. The rotor 27 has a rotor core portion 32, a rotor shaft portion 33, a rotor magnet 34, and a sensor magnet 35.

[0048] The stator core 28 is positioned radially outward from the rotor 27. The stator core 28 includes multiple laminated steel plates. The steel plates are metal plates mainly composed of iron. The stator core 28 is cylindrical. The stator core 28 has multiple teeth that support the coil 31.

[0049] The front insulator 29 is provided at the front of the stator core 28. The rear insulator 30 is provided at the rear of the stator core 28. Both the front insulator 29 and the rear insulator 30 are electrically insulating members made of synthetic resin. The front insulator 29 is positioned to cover a portion of the surface of the teeth. The rear insulator 30 is positioned to cover a portion of the surface of the teeth.

[0050] The coil 31 is mounted on the stator core 28 via a front insulator 29 and a rear insulator 30. Multiple coils 31 are arranged. The coils 31 are arranged around the teeth of the stator core 28 via the front insulator 29 and the rear insulator 30. The coils 31 and the stator core 28 are electrically isolated by the front insulator 29 and the rear insulator 30. Multiple coils 31 are connected via a fusing terminal 38.

[0051] The rotor core portion 32 and the rotor shaft portion 33 are each made of steel. The rotor shaft portion 33 protrudes in the front-rear direction from the end face of the rotor core portion 32. The rotor shaft portion 33 includes a front shaft portion 33F that protrudes forward from the front end face of the rotor core portion 32 and a rear shaft portion 33R that protrudes rearward from the rear end face of the rotor core portion 32.

[0052] The rotor magnet 34 is fixed to the rotor core 32. The rotor magnet 34 is cylindrical. The rotor magnet 34 is arranged around the rotor core 32.

[0053] The sensor magnet 35 is fixed to the rotor core 32. The sensor magnet 35 is annular in shape. The sensor magnet 35 is positioned on the front end surface of the rotor core 32 and the front end surface of the rotor magnet 34.

[0054] A sensor board 37 is attached to the front insulator 29. The sensor board 37 is fixed to the front insulator 29 by screws 29S. The sensor board 37 has a disc-shaped circuit board with a hole in the center and a rotation detection element supported by the circuit board. At least a portion of the sensor board 37 faces the sensor magnet 35. The rotation detection element detects the position of the rotor 27 in the direction of rotation by detecting the position of the sensor magnet 35 on the rotor 27.

[0055] The rotor shaft portion 33 is rotatably supported by the rotor bearing 39. The rotor bearing 39 includes a front rotor bearing 39F that rotatably supports the front shaft portion 33F, and a rear rotor bearing 39R that rotatably supports the rear shaft portion 33R.

[0056] The front rotor bearing 39F is held in the bearing box 24. The bearing box 24 has a recess 241 that extends forward from the rear surface of the bearing box 24. The front rotor bearing 39F is positioned in the recess 241. The rear rotor bearing 39R is held in the rear plate portion 21B. The front end of the rotor shaft portion 33 is positioned in the internal space of the hammer case 4 through the opening of the bearing box 24.

[0057] The fan 12 is fixed to the rear of the rear shaft portion 33R via a bush 12A. The fan 12 is positioned between the rear rotor bearing 39R and the stator 26. The fan 12 rotates with the rotation of the rotor 27. As the rotor shaft portion 33 rotates, the fan 12 rotates together with the rotor shaft portion 33.

[0058] A pinion gear 41 is formed at the front end of the rotor shaft portion 33. The pinion gear 41 is connected to at least a part of the reduction mechanism 7. The rotor shaft portion 33 is connected to the reduction mechanism 7 via the pinion gear 41.

[0059] The reduction gear 7 has a plurality of planetary gears 42 arranged around a pinion gear 41, and an internal gear 43 arranged around the plurality of planetary gears 42. Each of the pinion gear 41, planetary gears 42, and internal gear 43 is housed in a hammer case 4. Each of the plurality of planetary gears 42 meshes with the pinion gear 41. The planetary gears 42 are rotatably supported on the spindle 8 via pins 42P. The spindle 8 is rotated by the planetary gears 42. The internal gear 43 has internal teeth that mesh with the planetary gears 42. The internal gear 43 is rotatably fixed to the bearing box 24. The internal gear 43 is always non-rotatable relative to the bearing box 24. The bearing box 24 is rotatably fixed relative to the left housing 2L and the right housing 2R.

[0060] When the rotor shaft 33 rotates due to 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 revolving of the planetary gear 42, the spindle 8, which is connected to the planetary gear 42 via pin 42P, rotates at a lower rotational speed than the rotational speed of the rotor shaft 33.

[0061] The spindle 8 rotates with the rotational force of the motor 6. The spindle 8 transmits the rotational force of the motor 6 to the anvil 10 via the striking mechanism 9. The spindle 8 has a spindle shaft portion 801 and a flange portion 802 provided at the rear of the spindle shaft portion 801. The planetary gear 42 is rotatably supported on the flange portion 802 via a pin 42P. The rotation axis of the spindle 8 and the rotation axis AX of the motor 6 coincide. The spindle 8 rotates around the rotation axis AX. The spindle 8 is rotatably supported on the spindle bearing 44. A protrusion 803 is provided at the rear end of the spindle 8. The protrusion 803 projects rearward from the flange portion 802. The protrusion 803 is positioned to surround the spindle bearing 44.

[0062] The bearing box 24 is positioned around at least a portion of the spindle 8. The spindle bearing 44 is held in the bearing box 24. The bearing box 24 has a projection 242 that protrudes forward from the front surface of the bearing box 24. The spindle bearing 44 is positioned around the projection 242.

[0063] The striking mechanism 9 includes a hammer 47, a hammer ball 48, a coil spring 50, and a washer 53. The striking mechanism 9, including the hammer 47, hammer ball 48, coil spring 50, and washer 53, is housed in the first cylindrical portion 401 of the hammer case 4. The first cylindrical portion 401 is positioned around the hammer 47.

[0064] The hammer 47 is positioned in front of the reduction gear 7. The hammer 47 is positioned around the spindle shaft portion 801. The hammer 47 is supported by the spindle shaft portion 801.

[0065] The hammer 47 is rotated by the motor 6. The rotational force of the motor 6 is transmitted to the hammer 47 via the reduction gear 7 and the spindle 8. The hammer 47 is rotatable together with the spindle 8, which is rotated by the motor 6. The axis of rotation of the hammer 47, the axis of rotation of the spindle 8, and the axis of rotation AX of the motor 6 coincide. The hammer 47 rotates around the axis of rotation AX. The hammer 47 strikes the anvil 10 in the rotational direction.

[0066] Figure 10 is a front perspective view showing the hammer 47 according to this embodiment. Figure 11 is a front view of the hammer 47 according to this embodiment. Figure 12 is a rear perspective view showing the hammer 47 according to this embodiment. Figure 13 is a longitudinal cross-sectional view showing the hammer 47 according to this embodiment. Figure 14 is a transverse cross-sectional view showing the hammer 47 according to this embodiment.

[0067] The hammer 47 has a base portion 471, a front ring portion 472, a rear ring portion 473, a support ring portion 474, and a hammer projection portion 475.

[0068] The base portion 471 is positioned around the spindle shaft portion 801. The base portion 471 is annular in shape. The spindle shaft portion 801 is positioned inside the base portion 471.

[0069] The front ring portion 472 protrudes forward from the outer circumference of the base portion 471. The front ring portion 472 is cylindrical. The outer surface 472A of the front ring portion 472 is inclined radially inward toward the front.

[0070] The rear ring portion 473 protrudes rearward from the outer circumference of the base portion 471. The rear ring portion 473 is cylindrical.

[0071] The support ring portion 474 protrudes rearward from the inner circumference of the base portion 471. The support ring portion 474 is cylindrical. The support ring portion 474 is positioned around the spindle shaft portion 801. The support ring portion 474 is supported by the spindle shaft portion 801 via the hammer ball 48.

[0072] The hammer projection 475 protrudes radially inward from the inner circumferential surface of the front ring portion 472. The hammer projection 475 protrudes forward from the front surface of the base portion 471. The front surface 83 of the hammer projection 475 is positioned further forward than the front surface of the base portion 471. The front surface of the front ring portion 472 and the front surface 83 of the hammer projection 475 are located in the same plane. Two hammer projections 475 are arranged in the circumferential direction.

[0073] A recess 476 is formed by the rear surface of the base portion 471, the inner circumferential surface of the rear ring portion 473, and the outer circumferential surface of the support ring portion 474. The recess 476 is formed so as to recess forward from the rear surface of the hammer 47.

[0074] As shown in Figures 13 and 14, in the front-rear direction, the position of the rear end portion 473R of the rear ring portion 473 and the position of the rear end portion 474R of the support ring portion 474 are the same.

[0075] The base portion 471 has a groove 90 provided at the boundary with the hammer projection 475. The groove 90 is provided so as to extend in the radial direction. The groove 90 is provided on one circumferential side and the other circumferential side of the hammer projection 475.

[0076] The front surface of the base portion 471 includes a first front surface 81 and a second front surface 82 positioned differently from the first front surface 81 in the circumferential direction. The second front surface 82 is positioned in front of the first front surface 81.

[0077] One circumferential end of the first front surface 81 is connected to the other circumferential end of the front surface 83 of the hammer projection 475 via the first connecting surface 84. One circumferential end of the second front surface 82 is connected to the other circumferential end of the first front surface 81 via the second connecting surface 85. The groove 90 provided on the other circumferential side of the hammer projection 475 is defined by the first front surface 81, the first connecting surface 84 connected to one circumferential end of the first front surface 81, and the second connecting surface 85 connected to the other circumferential end of the first front surface 81.

[0078] The groove 90 provided on one circumferential side of the hammer projection 475 is defined by a first front surface 81, a first connecting surface 84 connected to the other circumferential end of the first front surface 81, and a second connecting surface 85 connected to one circumferential end of the first front surface 81.

[0079] The first connecting surface 84 includes a first plane 84A and a first curved surface 84B. The first plane 84A is parallel to the axis of rotation AX of the hammer 47. The first plane 84A is arranged to extend radially. In the groove 90 provided on the other circumferential side of the hammer projection 475, the first curved surface 84B is arranged to connect the rear end of the first plane 84A to one circumferential end of the first front surface 81. In the groove 90 provided on the one circumferential side of the hammer projection 475, the first curved surface 84B is arranged to connect the rear end of the first plane 84A to the other circumferential end of the first front surface 81.

[0080] The second connecting surface 85 includes a second plane 85A and a second curved surface 85B. The second plane 85A is parallel to the axis of rotation AX of the hammer 47. The second plane 85A is arranged to extend radially. In one groove 90, the second plane 85A is arranged to face the first plane 84A. In a groove 90 provided on the other circumferential side of the hammer projection 475, the second curved surface 85B is arranged to connect the rear end of the second plane 85A to the other circumferential end of the first front surface 81. In a groove 90 provided on one circumferential side of the hammer projection 475, the second curved surface 85B is arranged to connect the rear end of the second plane 85A to one circumferential end of the first front surface 81.

[0081] The hammer ball 48 is made of a metal such as steel. The hammer ball 48 is positioned between the spindle shaft portion 801 and the hammer 47. The spindle 8 has a spindle groove 804 in which at least a portion of the hammer ball 48 is positioned. The spindle groove 804 is provided on a portion of the outer circumferential surface of the spindle shaft portion 801. The hammer 47 has a hammer groove 477 in which at least a portion of the hammer ball 48 is positioned. The hammer groove 477 is provided on a portion of the inner circumferential surface of the support ring portion 474. The hammer ball 48 is positioned between the spindle groove 804 and the hammer groove 477. The hammer ball 48 can roll inside the spindle groove 804 and inside the hammer groove 477, respectively. The hammer 47 is movable along with the hammer ball 48. The spindle 8 and the hammer 47 can move relative to each other in the axial and rotational directions within the range of motion defined by the spindle groove 804 and the hammer groove 477.

[0082] The coil spring 50 is arranged around the spindle shaft portion 801. In this embodiment, the coil spring 50 includes a first coil spring 51 and a second coil spring 52 arranged in parallel with each other. The second coil spring 52 is arranged radially inward of the first coil spring 51.

[0083] The rear ends of the first coil spring 51 and the second coil spring 52 are supported by the flange portion 802. The front ends of the first coil spring 51 and the second coil spring 52 are positioned inside the recess 476. A washer 53 is positioned inside the recess 476. The front ends of the first coil spring 51 and the second coil spring 52 are supported by the washer 53. The washer 53 is ring-shaped. Each of the first coil spring 51 and the second coil spring 52 constantly generates an elastic force that moves the hammer 47 forward.

[0084] The washer 53 is positioned behind the base portion 471. The washer 53 supports the front end of the coil spring 50. In the radial direction, the washer 53 is positioned between the rear ring portion 473 and the support ring portion 474. The washer 53 is positioned inside the recess 476. The washer 53 is supported by the hammer 47 via a plurality of support balls 54. In the forward-rear range of motion of the hammer 47, when the hammer 47 is positioned furthest forward, the washer 53 is positioned forward of the rear end of the hammer ball 48.

[0085] The support ball 54 is positioned in a support groove 478 provided on the rear surface of the base portion 471. The support ball 54 supports the front surface of the washer 53. The support groove 478 is provided in a ring shape so as to surround the rotating shaft AX.

[0086] In both the radial and circumferential directions, the position of the support groove 478 is the same as the position of at least a portion of the second front surface 82. The base portion 471 has a thin-walled portion with a groove 90 and a thick-walled portion without a groove 90. The thin-walled portion includes the first front surface 81. The thick-walled portion includes the second front surface 82. The support groove 478 is provided in the thick-walled portion of the base portion 471.

[0087] The anvil 10 has an anvil shaft portion 101, an anvil projection portion 102, and an anvil convex portion 103.

[0088] The anvil shaft portion 101 is positioned in front of the spindle 8 and the hammer 47. The driver bit is mounted on the anvil shaft portion 101. The hexagonal bit hole 10A into which the driver bit is inserted is provided so as to extend rearward from the front end of the anvil shaft portion 101.

[0089] As shown in Figure 6, in the front-to-back direction, the rear end 10B of the hexagonal bit hole 10A is positioned at the same location as at least a portion of the front ring portion 472. Alternatively, the rear end 10B of the hexagonal bit hole 10A may be positioned at the same location as at least a portion of the base portion 471. This shortens the overall length (axial length), which is the distance between the rear end of the rear plate portion 21B and the front end of the anvil 10 in the front-to-back direction.

[0090] The anvil projection 102 protrudes radially outward from the rear of the anvil shaft portion 101. The anvil projection 102 is struck in the rotational direction by the hammer projection 475. The anvil projection 102 has a striking surface 104 that is struck by the hammer projection 475. The striking surface 104 is parallel to the rotation axis AX of the anvil 10. At least a portion of the first plane 84A of the hammer projection 475 faces the striking surface 104 of the anvil projection 102.

[0091] The front ring portion 472 is positioned radially outward from the anvil projection 102. In the axial direction, the position of the front ring portion 472 is the same as the position of at least a portion of the anvil projection 102. The outer circumference of the anvil projection 102 and the inner circumference of the front ring portion 472 are separated.

[0092] The base portion 471 is positioned behind the anvil projection 102. The rear surface of the anvil projection 102 and the front surface of the base portion 471 are separated.

[0093] The anvil projection 103 protrudes rearward from the rear end of the anvil 10. The spindle 8 is positioned behind the anvil 10. A spindle recess 805 is provided at the front end of the spindle shaft portion 801. The anvil projection 103 is positioned in the spindle recess 805.

[0094] As shown in Figure 7, at least a portion of the outer circumferential surface of the spindle shaft portion 801 is the hammer sliding surface 8A on which the support ring portion 474 of the hammer 47 slides. At least a portion of the inner circumferential surface of the spindle recess 805 is the anvil sliding surface 8B on which the anvil projection 103 of the anvil 10 slides. The anvil sliding surface 8B is positioned radially inward from the hammer sliding surface 8A. In the front-rear direction, at least a portion of the hammer sliding surface 8A and the anvil sliding surface 8B overlap. In the front-rear direction, the positions of the hammer sliding surface 8A and at least a portion of the anvil sliding surface 8B are the same, so the overall length (axial length) indicating the distance between the rear end of the rear plate portion 21B and the front end of the anvil 10 in the front-rear direction is shortened.

[0095] As shown in Figures 7 and 14, at least a portion of the inner circumferential surface of the support ring portion 474 of the hammer 47 is the sliding surface 479 on which the hammer sliding surface 8A of the spindle shaft portion 801 slides. The front end of the sliding surface 479 is positioned in front of the washer 53. By positioning the sliding surface 479 in front of the washer 53, the dimensions of the hammer 47 in the front-rear direction are shortened.

[0096] The anvil 10 is rotatably supported by an anvil bearing 46. The axis of rotation of the anvil 10 coincides with the axis of rotation of the hammer 47, the axis of rotation of the spindle 8, and the axis of rotation AX of the motor 6. The anvil 10 rotates around axis AX. The anvil bearing 46 is positioned around the anvil shaft portion 101. The anvil bearing 46 is positioned inside the second cylindrical portion 402 of the hammer case 4. The anvil bearing 46 is held in the second cylindrical portion 402 of the hammer case 4. The anvil bearing 46 rotatably supports the front portion of the anvil shaft portion 101. An O-ring 45 is positioned between the anvil bearing 46 and the anvil shaft portion 101. The O-ring 45 contacts the outer circumference of the anvil shaft portion 101 and the inner circumference of the anvil bearing 46, respectively.

[0097] In this embodiment, two anvil bearings 46 are arranged in the axial direction. Two O-rings 45 are also arranged in the axial direction.

[0098] The hammer projection 475 can contact the anvil projection 102. When the motor 6 is driven while the hammer 47 and the anvil projection 102 are in contact, the anvil 10 rotates together with the hammer 47 and the spindle 8.

[0099] The anvil 10 is struck in the rotational direction by the hammer 47. For example, in screw tightening operations, if the load acting on the anvil 10 becomes high, a situation may arise where the load of the coil spring 50 alone is insufficient to rotate the anvil 10. When the load of the coil spring 50 alone is insufficient to rotate the anvil 10, the rotation of the anvil 10 and the hammer 47 stops. The spindle 8 and the hammer 47 are relatively movable in the axial and circumferential directions, respectively, via the hammer ball 48. Even if 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 hammer ball 48 moves backward, guided by the spindle groove 804 and the hammer groove 477, respectively. The hammer 47 receives force from the hammer ball 48 and moves backward along with the hammer ball 48. In other words, the hammer 47 moves backward as the spindle 8 rotates while the anvil 10 is stopped from rotating. As the hammer 47 moves backward, contact between the hammer 47 and the anvil projection 102 is released.

[0100] As described above, the coil spring 50 constantly generates an elastic force that moves the hammer 47 forward. The hammer 47, which has moved backward, moves forward due to the elastic force of the coil spring 50. When the hammer 47 moves forward, it receives a rotational force from the hammer ball 48. That is, the hammer 47 moves forward while rotating. As the hammer 47 moves forward while rotating, the hammer projection 475 comes into contact with the anvil projection 102 while rotating. As a result, the anvil projection 102 is struck in the rotational direction by the hammer projection 475. The anvil 10 is subjected to both the power of the motor 6 and the inertial force of the hammer 47. Therefore, the anvil 10 can rotate around the rotation axis AX with high torque.

[0101] The bit holding mechanism 11 includes a ball 71, a sleeve 73, and a coil spring 74.

[0102] The anvil shaft portion 101 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 101. In this embodiment, two support recesses 76 are formed in the anvil shaft portion 101.

[0103] The ball 71 is movably supported in the anvil 10. The ball 71 is placed in a support recess 76. One ball 71 is placed in each support recess 76.

[0104] A through hole is formed in the anvil shaft portion 101, connecting the inner surface of the support recess 76 and the inner surface of the hexagonal bit hole 10A. The diameter of the ball 71 is smaller than the diameter of the through hole. With the ball 71 supported in the support recess 76, it is positioned inside the hexagonal bit hole 10A through at least a portion of the ball 71. The ball 71 can secure a driver bit inserted into the hexagonal bit hole 10A. The ball 71 is movable between an engaged position that secures the driver bit and a released position that releases the driver bit from being secured.

[0105] The sleeve 73 is a cylindrical member. The sleeve 73 is positioned around the anvil shaft portion 101. The sleeve 73 is movable around the anvil shaft portion 101 between a blocking position that prevents the ball 71 from moving radially outward and a permitting position that allows radial outward movement.

[0106] The positioning of the sleeve 73 in the blocking position prevents the ball 71 from moving radially outward. The positioning of the sleeve 73 in the blocking position maintains the state in which the driver bit is fixed by the ball 71.

[0107] When the sleeve 73 is moved to the permissible position, the ball 71 is allowed to move radially outward. When the sleeve 73 is positioned in the permissible position, the driver bit can be released from being fixed in place by the ball 71.

[0108] The coil spring 74 generates an elastic force that causes the sleeve 73 to move to the stop position. The coil spring 74 is positioned around the anvil shaft portion 101. The stop position is defined as being behind the allowable position. The coil spring 74 generates an elastic force that moves the sleeve 73 backward.

[0109] In this embodiment, the impact tool 1 is equipped with a cup washer 61 to suppress contact between the anvil projection 102 and the hammer case 4. In this embodiment, the cup washer 61 suppresses contact between the front surface of the anvil projection 102 and the rear end of the second cylindrical portion 402. The second cylindrical portion 402 receives the load from the anvil projection 102 via the cup washer 61.

[0110] The cup washer 61 is supported by the hammer case 4. In this embodiment, the outer circumference of the cup washer 61 is positioned in a groove 404 provided on the inner surface of the first cylindrical portion 401. The impact tool 1 also includes a restraining member 62 that prevents the cup washer 61 from coming out of the groove 404 to the rear.

[0111] Figure 15 is a front perspective view showing a cup washer 61 according to this embodiment. The cup washer 61 has an inner ring portion 611, an outer ring portion 612, and a connecting ring portion 613.

[0112] The inner ring portion 611 is positioned to face the front surface of the anvil projection 102. The inner ring portion 611 contacts the rear end surface of the anvil bearing 46.

[0113] The outer ring portion 612 is positioned around the anvil bearing 46. The outer ring portion 612 is positioned radially outward and forward of the inner ring portion 611. In the axial direction (front-rear direction), the position of the outer ring portion 612 and the position of at least a portion of the anvil bearing 46 are the same. The outer ring portion 612 is supported by the hammer case 4. The outer ring portion 612 is positioned in a groove 404 provided on the inner circumferential surface of the first cylindrical portion 401.

[0114] At least a portion of the rear surface of the case connection portion 403 faces the front surface of the outer ring portion 612. The rear surface of the case connection portion 403 and the front surface of the outer ring portion 612 face each other with a gap in between.

[0115] The connecting ring portion 613 is positioned to connect the outer edge of the inner ring portion 611 and the inner edge of the outer ring portion 612.

[0116] In this embodiment, the anvil bearing 46 is a ball bearing. The anvil bearing 46 has an inner ring, balls, and an outer ring. The inner ring of the anvil bearing 46 is in contact with the O-ring 45. The balls are arranged radially between the inner ring and the outer ring. The balls are in contact with both the inner ring and the outer ring, respectively. Multiple balls are arranged circumferentially. The outer ring is positioned radially outward from the inner ring and the balls. The outer ring of the anvil bearing 46 is in contact with the inner circumferential surface of the second cylindrical portion 402.

[0117] In this embodiment, the inner ring portion 611 contacts the rear end surface of the outer ring of the anvil bearing 46. The inner ring portion 611 does not contact the inner ring of the anvil bearing 46.

[0118] The restraining member 62 engages with the hammer case 4 and the cup washer 61, respectively. The restraining member 62 is supported by the hammer case 4. The restraining member 62 is positioned in the groove 404. The restraining member 62 prevents the cup washer from coming out rearward. A snap ring or a C-ring is exemplified as the restraining member 62. The restraining member 62 is positioned in the groove 404 so as to contact the rear surface of the outer ring portion 612. The outer ring portion 612 is supported by the hammer case 4 via the restraining member 62.

[0119] The cup washer 61 and the restraining member 62 prevent the anvil bearing 46 from falling out to the rear.

[0120] As shown in Figures 8 and 11, in this embodiment, the distance Wc between the first plane 84A and the second plane 85A is smaller than the circumferential dimension Wb of the anvil projection 102. The distance Wc represents the width of the groove 90. Also, the cross-sections of the first curved surface 84B and the second curved surface 85B are both arc-shaped. The distance Wc between the first plane 84A and the second plane 85A is greater than the sum of the radii of the first curved surface 84B and the radii of the second curved surface 85B.

[0121] [Impact Tools] Next, the operation of the impact tool 1 will be described. For example, when performing a screw tightening operation on a workpiece, the driver bit used for tightening is inserted into the hexagonal bit hole 10A of the anvil 10. The driver bit inserted into the hexagonal bit hole 10A is held by the bit holding mechanism 11. After the driver bit is mounted on the anvil 10, the operator grips the grip portion 22 with their right hand, for example, and pulls the trigger 14 with their right index finger. When the trigger 14 is pulled, power is supplied from the battery pack 25 to the motor 6, the motor 6 starts up, and the light 17 turns on at the same time. The start of the motor 6 causes the rotor shaft portion 33 of the rotor 27 to rotate. When the rotor shaft portion 33 rotates, the rotational force of the rotor shaft portion 33 is transmitted to the planetary gear 42 via the pinion gear 41. The planetary gear 42 rotates on its own axis and revolves around the pinion gear 41 while meshing with the internal teeth of the internal gear 43. The planetary gear 42 is rotatably supported on the spindle 8 via a pin 42P. Due to the revolution of the planetary gear 42, the spindle 8 rotates at a lower rotational speed than the rotational speed of the rotor shaft 33.

[0122] When the spindle 8 rotates while the hammer projection 475 and the anvil projection 102 are in contact, the anvil 10 rotates together with the hammer 47 and the spindle 8. The rotation of the anvil 10 allows the tightening operation to proceed.

[0123] As the tightening process progresses, if a load exceeding a predetermined value is applied to 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 backward. As the hammer 47 moves backward, contact between the hammer projection 475 and the anvil projection 102 is released. The hammer 47, having moved backward, moves forward while rotating due to the elastic force of the first coil spring 51 and the second coil spring 52. As the hammer 47 moves forward while rotating, the anvil projection 102 is struck in the rotational direction by the hammer projection 475. As a result, the anvil 10 rotates around the rotation axis AX with high torque. Therefore, the screw is tightened to the workpiece with high torque.

[0124] [Specifications] Figure 16 shows the specifications of the impact tool according to the embodiment and the impact tool according to the comparative example. Figure 17 shows the corner driving angle of the impact tool according to the embodiment and the impact tool according to the comparative example.

[0125] The impact tool according to this embodiment is the impact tool 1 described with reference to Figures 1 to 15.

[0126] The impact tools in Comparative Example 1, Comparative Example 2, and Comparative Example 3 are impact tools that are already manufactured and sold.

[0127] The power source for the impact tool in the embodiment and comparative examples 1, 2, and 3 is a battery pack that can be attached to and removed from the impact tool. The rated voltage of the battery pack is 18V. However, the rated voltage of the battery pack is arbitrary. The rated voltage of the battery pack may be 10.8V, 14.4V, 25.2V, or 36V.

[0128] The maximum tightening torque of the impact tools according to the embodiment and comparative examples 1, 2, and 3 is 140 Nm or more. As shown in Figure 16, the maximum tightening torque of the impact tool according to the embodiment is 140 Nm. The maximum tightening torques of the impact tools according to comparative examples 1, 2, and 3 are 155 Nm, 165 Nm, and 206 Nm, respectively. The maximum tightening torque of the impact tool according to the embodiment can take any value between 150 Nm and 230 Nm. The maximum tightening torque of the impact tool according to the embodiment can take any one of the values ​​of 150 Nm, 160 Nm, 170 Nm, 180 Nm, 190 Nm, 200 Nm, 210 Nm, 220 Nm, and 230 Nm, or a value between these values.

[0129] As shown in Figure 3, when the total length La (axis length) is defined as the distance between the rear end of the motor housing 21 and the front end of the anvil 10 in the front-rear direction parallel to the rotation axis AX of the motor 6, the total length La of the impact tool according to the embodiment is 97 mm. The total lengths La of the impact tools according to Comparative Examples 1, 2, and 3 are 98 mm, 99 mm, and 100 mm, respectively. The total length La of the impact tool according to the embodiment can take any value between 90 mm and 98 mm. The total length La of the impact tool according to the embodiment can take any one of the following values: 98 mm, 97 mm, 96 mm, 95 mm, 94 mm, 93 mm, 92 mm, 91 mm, and 90 mm, or a value between these values.

[0130] As shown in Figure 4, when the dimensions of the impact tool with the battery pack attached in the left-right direction, i.e., the distance between the left and right ends of the impact tool and battery pack in the left-right direction, is defined as the maximum width Ma, the maximum width Ma of the impact tool according to the embodiment is 81 mm, and the maximum widths Ma of the impact tools according to Comparative Examples 1, 2, and 3 are 84 mm, 79 mm, and 78 mm, respectively. The maximum width Ma may be the width of the battery pack or the width of the battery holder.

[0131] As shown in Figure 3, when the height Ha is defined as the distance between the upper end of the motor housing 21 and the lower end of the battery pack 25 mounted on the battery mounting section 13 in the vertical direction, the height Ha of the impact tool according to the embodiment is 234 mm. The heights Ha of the impact tools according to Comparative Examples 1, 2, and 3 are 243 mm, 237 mm, and 256 mm, respectively. The height Ha of the impact tool according to the embodiment can take any value between 226 mm and 234 mm. The height Ha of the impact tool according to the embodiment can take any one of the values ​​234 mm, 232 mm, 230 mm, 228 mm, and 226 mm, or a value between these values.

[0132] As shown in Figures 4 and 7, if the dimensions of the motor housing 21 in the left-right direction, that is, the distance between the left end and the right end of the motor housing 21 in the left-right direction, are defined as the head width Wa, then the head width Wa of the impact tool according to the embodiment is 53.4 mm. The head widths Wa of the impact tools according to Comparative Examples 1, 2, and 3 are 63.5 mm, 66.5 mm, and 66 mm, respectively. The head width Wa of the impact tool according to the embodiment can take any value between 47 mm and 53 mm. The head width Wa of the impact tool according to the embodiment can take any one of the values ​​53 mm, 52 mm, 51 mm, 50 mm, 49 mm, 48 mm, and 47 mm, or a value between these values.

[0133] As shown in Figure 3, when the distance between the rotation axis AX and the upper end of the motor housing 21 in the vertical direction is defined as the center height Hc, the center height Hc of the impact tool according to the embodiment is 26.3 mm. The center heights Hc of the impact tools according to Comparative Examples 1, 2, and 3 are 30 mm, 30 mm, and 35 mm, respectively. The center height Hc of the impact tool according to the embodiment can take any value between 22 mm and 28 mm. The center height Hc of the impact tool according to the embodiment can take any one of the following values: 28 mm, 27 mm, 26 mm, 25 mm, 24 mm, 23 mm, and 22 mm, or a value between these values.

[0134] The ratio of the head width Wa to the total length La [Wa / La] is 0.55 for the impact tool according to the embodiment, and 0.65, 0.67, and 0.66 for the impact tools according to Comparative Examples 1, 2, and 3, respectively. The ratio [Wa / La] for the impact tool according to the embodiment can take any value between 0.52 and 0.64. The ratio [Wa / La] for the impact tool according to the embodiment can take any one of the following values: 0.64, 0.63, 0.62, 0.61, 0.60, 0.59, 0.58, 0.57, 0.56, 0.55, 0.54, 0.53, and 0.52, or a value between these values.

[0135] The mass, no-load rotation speed, and number of impacts of the impact tools according to the embodiment and comparative examples 1, 2, and 3 are as shown in Figure 16.

[0136] As shown in Figure 16, the impact tool according to the embodiment satisfies the conditions that the maximum tightening torque is 140 Nm or more, the overall length La is 100 mm or less, and the center height Hc is 29 mm or less. Furthermore, the impact tool according to the embodiment satisfies the condition that the ratio of the head width Wa to the overall length La [Wa / La] is 0.6 or less. The impact tool according to the embodiment also satisfies the condition that the head width Wa is 65 mm or less.

[0137] As shown in Figure 3, if the total length Lh is defined as the distance between the rear end of the motor housing 21 and the front end of the driver bit 300 mounted on the anvil 10 in the front-rear direction, the impact tool according to the embodiment satisfies the condition that the total length Lh is 140 mm or less.

[0138] Figures 18, 19, and 20 are diagrams illustrating the corner driving conditions for impact tools. As shown in Figures 18, 19, and 20, corner driving refers to the operation of tightening a screw with a driver bit 300 at a specified distance Hw above the floor surface WL on a wall surface WL perpendicular to the floor surface FL. The corner driving angle θ refers to the angle between the rotation axis AX and the floor surface FL when tightening a screw with a driver bit 300 at a specified distance Hw above the floor surface WL on a wall surface WL perpendicular to the floor surface FL. In the evaluation tests disclosed herein, the specified distance Hw was set to 10 mm. That is, the corner driving angle θ related to the evaluation tests disclosed herein refers to the angle between the rotation axis AX and the floor surface FL when tightening a screw with a driver bit 300 at a position 10 mm above the floor surface FL on a wall surface WL perpendicular to the floor surface FL.

[0139] In the evaluation tests disclosed herein, a driver bit 300 with a length of 65 mm was used. Corner driving was performed in three positions: directly above, directly to the side, and at a 45-degree angle. As shown in Figure 18, "directly above" refers to the position of the impact tool where the battery holder 23 is positioned directly above the motor housing 21. As shown in Figure 19, "directly to the side" refers to the position of the impact tool where the battery holder 23 is positioned directly to the side of the motor housing 21. As shown in Figure 20, "45-degree angle" refers to the position of the impact tool where the battery holder 23 is positioned at an upward 45-degree angle to the motor housing 21.

[0140] As shown in Figure 17, in the overhead position, the corner-driving angle θ of the impact tool according to the embodiment is 11.4 degrees. The corner-driving angles θ of the impact tools according to Comparative Examples 2 and 3 are 12.2 degrees and 12.5 degrees, respectively. In the sideways position, the corner-driving angle θ of the impact tool according to the embodiment is 11.0 degrees. The corner-driving angles θ of the impact tools according to Comparative Examples 2 and 3 are 16.2 degrees and 15.7 degrees, respectively. In the 45-degree angle position, the corner-driving angle θ of the impact tool according to the embodiment is 11.9 degrees. The corner-driving angles θ of the impact tools according to Comparative Examples 2 and 3 are 13.2 degrees and 12.9 degrees, respectively. Note that the impact tool according to Comparative Example 1 was unable to drive into corners. Thus, the corner-driving angle θ of the impact tool according to the embodiment satisfies the condition that it is 12 degrees or less.

[0141] [effect] As described above, in this embodiment, the impact tool 1 comprises a motor 6 having a stator 26 and a rotor 27, at least a portion of which is located inside the stator 26 and rotates around a rotation axis AX; a spindle 8, located in front of the stator 26 and rotated by the rotational force of the rotor 27; an anvil 10, at least a portion of which is located in front of the spindle 8 and on which a driver bit 300 is mounted; a hammer 47 that strikes the anvil 10 in the rotational direction; and a housing 2 having a motor housing portion 21 that houses the motor 6.

[0142] The maximum tightening torque is 140 Nm or more.

[0143] The total length La, which indicates the distance between the rear end of the motor housing 21 and the front end of the anvil 10 in the front-rear direction parallel to the rotation axis AX, is 100 mm or less.

[0144] The center height Hc, which indicates the distance between the rotation axis AX and the upper end of the motor housing 21 in the vertical direction, is 29 mm or less.

[0145] The total length Lh, which indicates the distance between the rear end of the motor housing 21 and the front end of the driver bit 300 mounted on the anvil 10 in the front-rear direction, is 140 mm or less.

[0146] When tightening a screw located 10 mm above the floor surface FL on a wall surface WL perpendicular to the floor surface FL using a driver bit 300, the corner driving angle θ, which indicates the angle between the rotation axis AX and the floor surface FL, is 12 degrees or less.

[0147] The head width Wa, which indicates the dimensions of the motor housing 21 in the left-right direction, is 65 mm or less.

[0148] The ratio of the head width Wa to the total length La [Wa / La] is 0.6 or less.

[0149] With the above configuration, even in narrow spaces or corners, the worker can smoothly perform work using the impact tool 1. For example, as shown in Figure 18, when performing corner nailing at a corner formed by the floor surface FL and the wall surface WL, the impact tool 1 according to the embodiment can smoothly perform the tightening work at a position where the specified distance Hw is smaller (lower position) than the impact tool according to the comparative example.

[0150] [Other embodiments] In the embodiments described above, the impact tool 1 is not limited to an impact driver. The impact tool 1 may also be an impact wrench.

[0151] In the above embodiment, the power source for the impact tool 1 is the battery pack 25. The power source for the impact tool 1 may also be commercial power (AC power). [Explanation of Symbols]

[0152] 1…Impact tool, 2…Housing, 2L…Left housing, 2R…Right housing, 2S…Screw, 4…Hammer case, 5A…Hammer case cover, 5B…Bumper, 5C…Housing cover, 6…Motor, 7…Reduction mechanism, 8…Spindle, 8A…Hammer sliding surface, 8B…Anvil sliding surface, 9…Impact mechanism, 10…Anvil, 10A…Hexagonal bit hole, 10B…Rear end, 11…Bit holding mechanism, 12…Fan, 12A…Bush, 13…Battery mounting section, 14…Trigger, 15…Forward / reverse switch, 16…Operation display section, 16A…First operation button, 16B…Second operation Button, 17…Light, 18…Controller, 19…Air intake, 20…Exhaust, 21…Motor housing, 21A…Cylindrical section, 21B…Rear plate section, 22…Grip section, 23…Battery holder, 24…Bearing box, 24A…O-ring, 25…Battery pack, 25A…Release button, 26…Stator, 27…Rotor, 28…Stator core, 29…Front insulator, 29S…Screw, 30…Rear insulator, 31…Coil, 32…Rotor core section, 33…Rotor shaft section, 33F…Front shaft section, 33R…Rear shaft section, 34…Rotor magnet, 35… 37...Sensor magnet, 38...Fusing terminal, 39...Rotor bearing, 39F...Front rotor bearing, 39R...Rear rotor bearing, 41...Pinion gear, 42...Planetary gear, 42P...Pin, 43...Internal gear, 44...Spindle bearing, 45...O-ring, 46...Anvil bearing, 47...Hammer, 48...Hammer ball, 50...Coil spring, 51...First coil spring, 52...Second coil spring, 53...Washer, 54...Support ball, 61...Cup washer, 62...Restraining member, 71...Ball, 73... Sleeve, 74... Coil spring, 76... Support recess, 81... First front surface, 82... Second front surface, 83... Front surface, 84... First connection surface, 84A... First plane, 84B... First curved surface, 85... Second connection surface, 85A... Second plane, 85B... Second curved surface, 90... Groove, 101... Anvil shaft part, 102... Anvil projection, 103... Anvil convex part, 104... Striking surface, 241... Recess, 242... Convex part, 300... Driver bit (bit), 401... First cylindrical part, 402... Second cylindrical part, 403... Case connection part, 404... Groove part, 471... Base part, 472... Front ring part, 472A... Outer circumference surface,473...Rear ring section, 473R...Rear end section, 474...Support ring section, 474R...Rear end section, 475...Hammer projection section, 476...Recess section, 477...Hammer groove, 478...Support groove, 479...Sliding surface, 611...Inner ring section, 612...Outer ring section, 613...Connecting ring section, 801...Spindle shaft section, 802...Flange section, 803...Protrusion section, 804...Spindle groove, 805...Spindle recess section, AX...Rotation axis.

Claims

1. A motor having a stator and a rotor, at least part of which is located inside the stator and rotates around a rotation axis, A spindle positioned in front of the stator and rotated by the rotational force of the rotor, An anvil on which a bit is mounted, at least a portion of which is positioned in front of the spindle, A hammer that strikes the anvil in the rotational direction, The housing comprises a motor housing section for housing the motor, The maximum tightening torque is 140 Nm or more. The total length La, which indicates the distance between the rear end of the motor housing and the front end of the anvil in the front-rear direction parallel to the rotation axis, is 100 mm or less. The center height Hc, which indicates the distance between the rotation axis and the upper end of the motor housing in the vertical direction, is 29 mm or less. The corner driving angle θ, which indicates the angle between the rotation axis and the floor surface when tightening a screw located 10 mm above the floor surface on a wall surface perpendicular to the floor surface using the bit, is 12 degrees or less. Impact tools.

2. The total length Lh, which indicates the distance between the rear end of the motor housing and the front end of the bit mounted on the anvil in the front-rear direction, is 140 mm or less. The impact tool according to claim 1.

3. The ratio of the head width Wa to the total length La, which indicates the dimensions of the motor housing in the left-right direction, is 0.6 or less. The impact tool according to claim 1.

4. A motor having a stator and a rotor, at least part of which is located inside the stator and rotates around a rotation axis, A spindle positioned in front of the stator and rotated by the rotational force of the rotor, An anvil on which a bit is mounted, at least a portion of which is positioned in front of the spindle, A hammer that strikes the anvil in the rotational direction, The housing comprises a motor housing section for housing the motor, The maximum tightening torque is 140 Nm or more. The total length La, which indicates the distance between the rear end of the motor housing and the front end of the anvil in the front-rear direction parallel to the rotation axis, is 100 mm or less. The corner driving angle θ, which indicates the angle between the rotation axis and the floor surface when tightening a screw located 10 mm above the floor surface on a wall surface perpendicular to the floor surface using the bit, is 12 degrees or less. Impact tools.

5. A motor having a stator and a rotor, at least part of which is located inside the stator and rotates around a rotation axis, A spindle positioned in front of the stator and rotated by the rotational force of the rotor, An anvil on which a bit is mounted, at least a portion of which is positioned in front of the spindle, A hammer that strikes the anvil in the rotational direction, The housing comprises a motor housing section for housing the motor, The maximum tightening torque is 140 Nm or more. The total length Lh, which indicates the distance between the rear end of the motor housing and the front end of the bit mounted on the anvil in the front-rear direction parallel to the rotation axis, is 140 mm or less. The corner driving angle θ, which indicates the angle between the rotation axis and the floor surface when tightening a screw located 10 mm above the floor surface on a wall surface perpendicular to the floor surface using the bit, is 12 degrees or less. Impact tools.

6. A motor having a stator and a rotor, at least part of which is located inside the stator and rotates around a rotation axis, A spindle positioned in front of the stator and rotated by the rotational force of the rotor, An anvil on which a bit is mounted, at least a portion of which is positioned in front of the spindle, A hammer that strikes the anvil in the rotational direction, The housing comprises a motor housing section for housing the motor, The maximum tightening torque is 140 Nm or more. The total length La, which indicates the distance between the rear end of the motor housing and the front end of the anvil in the front-rear direction parallel to the rotation axis, is 100 mm or less. The head width Wa, which indicates the dimensions of the motor housing in the left-right direction, is 65 mm or less. The ratio of the head width Wa to the total length La is 0.6 or less. The corner driving angle θ, which indicates the angle between the rotation axis and the floor surface when tightening a screw located 10 mm above the floor surface on a wall surface perpendicular to the floor surface using the bit, is 12 degrees or less. Impact tools.

Images