Impact tool

Abstract

To suppress an anvil from coming off.SOLUTION: An impact tool comprises: a motor; a striking mechanism that can rotate with an output rotary shaft extending in a longitudinal direction as the center and is driven by the motor; an anvil which has an anvil shaft part arranged closer to a front side than the striking mechanism and an anvil protrusion part that protrudes outward in a radial direction from a rear end part of the anvil shaft part and is struck by the striking mechanism in a rotating direction with the output rotary shaft as the center; a hammer case for storing the striking mechanism; an anvil bearing held on the hammer case and arranged around the anvil shaft part; a first groove part formed on an outer peripheral surface of the anvil shaft part to surround the output rotary shaft; a second groove part formed on an inner peripheral surface of the anvil bearing to surround the output rotary shaft; and a suppressing member including a first part arranged at the first groove part and a second part arranged at the second groove part.SELECTED DRAWING: Figure 13

Description

Technical Field

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

Background Art

[0002] In the technical field related to impact tools, an impact wrench 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] An impact tool has an anvil. When a high load acts on the anvil and the anvil breaks, at least a part of the anvil may fall off from the impact tool.

[0005] The technology disclosed in this specification aims to suppress the detachment of the anvil.

Means for Solving the Problems

[0006] This specification discloses an impact tool. The impact tool may include a motor, a striking mechanism driven by the motor, an anvil struck in a rotational direction by the striking mechanism, a hammer case housing the striking mechanism, and an anvil bearing. The striking mechanism may be rotatable about an output rotation axis extending in the front-rear direction. The anvil may have an anvil shaft portion disposed forward of the striking mechanism and an anvil protrusion protruding radially outward from a rear end portion of the anvil shaft portion. The anvil protrusion may be struck in a rotational direction about the output rotation axis by the striking mechanism. The anvil bearing may be held by the hammer case and disposed around the anvil shaft portion. A first groove portion may be formed on an outer peripheral surface of the anvil shaft portion so as to surround the output rotation axis. A second groove portion may be formed on an inner peripheral surface of the anvil bearing so as to surround the output rotation axis. The impact tool may include a suppression member including a first portion disposed in the first groove portion and a second portion disposed in the second groove portion.

Effect of the Invention

[0007] According to the technology disclosed in this specification, the dropping off of the anvil 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

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

DETAILED DESCRIPTION OF THE INVENTION

[0009] In one or more embodiments, the impact tool may include a motor, a striking mechanism driven by the motor, an anvil struck in a rotational direction by the striking mechanism, a hammer case housing the striking mechanism, and an anvil bearing. The striking mechanism may be rotatable about an output rotation axis extending in the front-rear direction. The anvil may have an anvil shaft portion disposed forward of the striking mechanism and an anvil protrusion protruding radially outward from a rear end portion of the anvil shaft portion. The anvil protrusion may be struck in a rotational direction about the output rotation axis by the striking mechanism. The anvil bearing may be held by the hammer case and disposed around the anvil shaft portion. A first groove portion may be formed on an outer peripheral surface of the anvil shaft portion so as to surround the output rotation axis. A second groove portion may be formed on an inner peripheral surface of the anvil bearing so as to surround the output rotation axis. The impact tool may include a restraining member including a first portion disposed in the first groove portion and a second portion disposed in the second groove portion.

[0010] In the above configuration, since a restraining member including a first portion disposed in the first groove portion and a second portion disposed in the second groove portion is provided, when at least a part of the anvil shaft portion is damaged, the anvil shaft portion is caught by the restraining member supported by the second groove portion. Therefore, the anvil shaft portion is prevented from coming out forward from the hammer case. Accordingly, the dropout of the anvil from the impact tool is suppressed.

[0011] In one or more embodiments, the restraining member may be ring-shaped and surround the output rotation axis.

[0012] In the above configuration, when at least a part of the anvil shaft portion is damaged, the anvil shaft portion can be sufficiently caught by the restraining member supported by the second groove portion.

[0013] In one or more embodiments, the restraining member may be an O-ring that contacts each of the inner surfaces of the first groove portion and the second groove portion.

[0014] In the above configuration, the boundary between the inner surface of the first groove portion and the inner surface of the second groove portion is sealed by an O-ring. Therefore, for example, it is possible to suppress grease supplied to the striking mechanism from leaking from the boundary between the inner surface of the first groove portion and the inner surface of the second groove portion.

[0015] In one or more embodiments, the anvil shaft portion may have a fracture starting portion having a sectional modulus smaller than the sectional modulus of the anvil shaft portion in the first groove portion. The fracture starting portion may be disposed rearward of the first groove portion.

[0016] In the above configuration, when a high load acts on the anvil shaft portion, the anvil shaft portion fractures at the fracture starting portion. Since the anvil shaft portion fractures rearward of the first groove portion, the first groove portion of the anvil shaft portion can be caught by the restraining member supported by the second groove portion.

[0017] In one or more embodiments, the impact tool may include a third groove portion formed on the outer peripheral surface of the anvil shaft portion so as to surround the output rotation shaft rearward of the first groove portion. The diameter of the anvil shaft portion in the third groove portion may be smaller than the diameter of the anvil shaft portion in the first groove portion. The fracture starting portion may include the anvil shaft portion in the third groove portion.

[0018] In the above configuration, by forming the third groove portion, the fracture starting portion is easily formed.

[0019] In one or more embodiments, the inner surface of the first groove portion may include a first front side surface facing rearward, a first rear side surface disposed rearward of the first front side surface and facing forward, and a first circumferential surface connected to each of the radially inner end portions of the first front side surface and the first rear side surface and facing radially outward. The inner surface of the second groove portion may include a second front side surface facing rearward and a second circumferential surface connected to the radially outer end portion of the second front side surface and facing radially inward.

[0020] In the above configuration, since each of the first groove portion and the second groove portion is properly formed, when the anvil shaft portion breaks at the break starting portion, the first groove portion of the anvil shaft portion can be caught by the restraining member supported by the second groove portion.

[0021] In one or more embodiments, in a state where the anvil shaft portion breaks at the break starting portion, the restraining member may contact each of the first rear surface and the second front surface.

[0022] In the above configuration, when the anvil shaft portion breaks at the break starting portion, the first rear surface of the first groove portion is caught by the restraining member supported by the second front surface of the second groove portion, so that the anvil shaft portion is suppressed from coming out forward from the hammer case.

[0023] In one or more embodiments, the hammer case may have a bearing support surface that contacts the front end portion of the anvil bearing.

[0024] In the above configuration, since the front end portion of the anvil bearing contacts the bearing support surface of the hammer case, the anvil bearing is suppressed from coming out forward from the hammer case. Even if the anvil shaft portion breaks, the anvil bearing does not come out forward from the hammer case, so that the restraining member supported by the second groove portion of the anvil bearing also does not come out forward from the hammer case. Therefore, when at least a part of the anvil shaft portion breaks, the anvil shaft portion is caught by the restraining member supported by the second groove portion, so that the anvil shaft portion is suppressed from coming out forward from the hammer case.

[0025] In one or more embodiments, the anvil bearing may be a sliding bearing.

[0026] In the above configuration, the second groove portion is properly formed on the inner peripheral surface of the anvil bearing that is a sliding bearing.

[0027] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings, but the present disclosure is not limited to the embodiments. The components of the embodiments described below can be combined as appropriate. Also, there may be cases where some components are not used.

[0028] In the embodiment, the terms "left", "right", "front", "rear", "upper", and "lower" are used to describe the positional relationship of each part. These terms indicate the relative position or direction based on the center of the impact tool 1. The left - right direction, the front - rear direction, and the upper - lower direction are orthogonal to each other.

[0029] [Impact tool] FIG. 1 is a perspective view from the left front showing the impact tool 1 according to the embodiment. FIG. 2 is a perspective view from the right rear showing the impact tool 1 according to the embodiment. FIG. 3 is a view of the impact tool 1 according to the embodiment as seen from the right. FIG. 4 is a view of the impact tool 1 according to the embodiment as seen from the left. FIG. 5 is a view of the impact tool 1 according to the embodiment as seen from the rear. FIG. 6 is a view of the impact tool 1 according to the embodiment as seen from the front. FIG. 7 is a view of the impact tool 1 according to the embodiment as seen from above. FIG. 8 is a view of the impact tool 1 according to the embodiment as seen from below. FIG. 9 is a cross - sectional view showing the impact tool 1 according to the embodiment, corresponding to the sectional view taken along line B - B in FIG. 7 with the arrow indicating the viewing direction. FIG. 10 is a cross - sectional view showing the impact tool 1 according to the embodiment, corresponding to the sectional view taken along line A - A in FIG. 3 with the arrow indicating the viewing direction.

[0030] In the embodiment, the impact tool 1 is an impact wrench, which is a kind of fastening tool. The impact tool 1 includes a main body housing 2, a grip housing 3, a motor housing 4, a gear case 5, a hammer case 6, a side handle 7, a bumper 8, a battery mounting portion 9, a motor 10, a controller 11, a fan 12, a speed reduction mechanism 13, a spindle 14, a striking mechanism 15, an anvil 16, a trigger switch 17, and a light assembly 18.

[0031] The main body housing 2 houses the gear case 5. At least a part of the main body housing 2 is disposed in front of the grip housing 3. At least a part of the main body housing 2 is disposed above the motor housing 4. The main body housing 2 is disposed behind the hammer case 6. The main body housing 2 is connected to the grip housing 3. The main body housing 2 is connected to the motor housing 4. The main body housing 2 is fixed to the hammer case 6.

[0032] The main body housing 2 is made of synthetic resin. As the synthetic resin forming the main body housing 2, nylon resin is exemplified. The main body housing 2 includes a left main body housing 2L and a right main body housing 2R disposed to the right of the left main body housing 2L. The left main body housing 2L and the right main body housing 2R constitute a pair of split housings. The left main body housing 2L and the right main body housing 2R are fixed by a plurality of screws 19.

[0033] The main body housing 2 has a main body portion 20 and a protruding portion 21 protruding rearward from the main body portion 20. The main body portion 20 has a gear case accommodating portion 22 that accommodates the gear case 5 and a motor housing connecting portion 23 that is connected to the motor housing 4. The gear case accommodating portion 22 has a cylindrical portion 24 disposed around the gear case 5 and a rear wall portion 25 disposed at the rear end portion of the cylindrical portion 24. The motor housing connecting portion 23 is disposed so as to protrude downward from the rear portion of the gear case accommodating portion 22. The motor housing connecting portion 23 is disposed behind the motor housing 4. The protruding portion 21 is connected to the grip housing 3. A part of the protruding portion 21 protrudes rearward from the gear case accommodating portion 22. A part of the protruding portion 21 protrudes rearward from the motor housing connecting portion 23.

[0034] The grip housing 3 is grasped by the operator. The grip housing 3 houses the controller 11. The grip housing 3 supports the trigger switch 17. At least a part of the grip housing 3 is disposed rearward of the main body housing 2. The grip housing 3 is connected to the main body housing 2 so as to be relatively movable with respect to the main body housing 2.

[0035] The grip housing 3 is made of synthetic resin. As the synthetic resin forming the grip housing 3, nylon resin is exemplified. The grip housing 3 includes a left grip housing 3L and a right grip housing 3R disposed to the right of the left grip housing 3L. The left grip housing 3L and the right grip housing 3R constitute a pair of split housings. The left grip housing 3L and the right grip housing 3R are fixed by a plurality of screws 26.

[0036] The grip housing 3 has a grip portion 27 grasped by the operator, a controller housing portion 28 housing the controller 11, a battery connection portion 29 where the battery mounting portion 9 is disposed, and a connection portion 30 connected to the protruding portion 21 of the main body housing 2. The grip portion 27 includes a rear grip portion 31 extending upward from the rear portion of the controller housing portion 28, an upper grip portion 32 extending forward from the upper end portion of the rear grip portion 31, and a front grip portion 33 extending downward from the front end portion of the upper grip portion 32. The front grip portion 33 is disposed so as to connect the front end portion of the upper grip portion 32 and the upper portion of the connection portion 30. The grip portion 27 is formed substantially in an annular shape. The trigger switch 17 is disposed on the upper portion of the rear grip portion 31. The battery connection portion 29 is disposed at the lower portion of the controller housing portion 28. At least a part of the battery connection portion 29 is disposed forward of the controller housing portion 28. The connection portion 30 is disposed at the front portion of the controller housing portion 28.

[0037] The motor housing 4 houses the motor 10. The motor housing 4 is disposed below the gear case 5. The motor housing 4 is connected to the main body housing 2. The motor housing 4 is fixed to the gear case 5.

[0038] The motor housing 4 is made of synthetic resin. As the synthetic resin forming the motor housing 4, polycarbonate resin is exemplified.

[0039] The motor housing 4 has a cylindrical portion 34 disposed around the motor 10 and a lower wall portion 35 disposed at the lower end of the cylindrical portion 34.

[0040] An opening 36 is provided at the upper part of the motor housing 4. An opening 37 is formed at the lower part of the gear case housing portion 22.

[0041] An opening 38 is provided at the rear part of the motor housing 4. An opening 39 is provided at the motor housing connection portion 23. An opening 40A is provided at the rear part of the main body housing 2. An opening 40B is provided at the front part of the grip housing 3. The internal space of the motor housing 4 and the internal space of the controller housing portion 28 are connected via the opening 38, the opening 39, the opening 40A, and the opening 40B.

[0042] The gear case 5 houses at least a part of the speed reduction mechanism 13. The gear case 5 is disposed behind the hammer case 6. The gear case 5 is fixed to the hammer case 6.

[0043] The gear case 5 is made of metal. As the metal forming the gear case 5, aluminum or magnesium is exemplified.

[0044] The gear case 5 is substantially cylindrical. An opening 41 is provided at the front part of the gear case 5. An opening 42 is provided at the rear part of the gear case 5. An opening 43 is provided at the lower part of the gear case 5. A bearing cover 44 is disposed at the opening 42 of the gear case 5. The bearing cover 44 is fixed to the rear part of the gear case 5 by screws 45.

[0045] The hammer case 6 houses the striking mechanism 15. The hammer case 6 is connected to the front portion of the main body housing 2. The hammer case 6 is connected to the front portion of the gear case 5.

[0046] The hammer case 6 is made of metal. Aluminum is exemplified as the metal forming the hammer case 6.

[0047] The hammer case 6 is substantially cylindrical. The hammer case 6 has a first cylindrical portion 46 and a second cylindrical portion 47. The first cylindrical portion 46 is disposed around the striking mechanism 15. The second cylindrical portion 47 is disposed forward of the first cylindrical portion 46. The outer diameter of the second cylindrical portion 47 is smaller than the outer diameter of the first cylindrical portion 46. An opening 48 is provided at the rear portion of the first cylindrical portion 46. An opening 49 is provided at the front portion of the second cylindrical portion 47. The front end portion of the gear case 5 is inserted into the opening 48.

[0048] The gear case 5 and the hammer case 6 are fixed by a plurality of screws 50. The gear case 5 has a plurality of screw bosses 51. At least a part of the main body housing 2 is disposed so as to cover the screw bosses 51. The main body housing 2 is also fixed to the hammer case 6 by a plurality of screws 50. The hammer case 6 has a plurality of screw bosses 52. The screws 50 are inserted into the through holes provided in the main body housing 2 and the through holes provided in the screw bosses 51 of the gear case 5. The screws 50 are inserted into the screw holes provided in the screw bosses 52 of the hammer case 6. The screws 50 are inserted into the through holes of the main body housing 2 and the through holes of the screw bosses 51 from the rear of the screw bosses 51 and then inserted into the screw holes of the screw bosses 52.

[0049] The motor housing 4 and the gear case 5 are fixed by a plurality of screws 53. The motor housing 4 has a plurality of screw bosses 54. The screws 53 are inserted into the through holes provided in the screw bosses 54 of the motor housing 4. The screws 53 are inserted into the screw holes provided in the lower portion of the gear case 5. The screws 53 are inserted into the through holes of the screw bosses 54 from below the screw bosses 54 and then inserted into the screw holes of the gear case 5.

[0050] The internal space of the motor housing 4 and the internal space of the gear case 5 are connected via the opening 36 and the opening 43.

[0051] The internal space of the gear case 5 and the internal space of the hammer case 6 are connected via the opening 41 and the opening 48.

[0052] The side handle 7 is grasped by the operator. The side handle 7 has a handle portion 55 grasped by the operator and a base portion 56 fixed to the hammer case 6. The handle portion 55 is disposed to the left of the hammer case 6. The base portion 56 includes a first base portion 57 and a second base portion 58 disposed below the first base portion 57. Each of the first base portion 57 and the second base portion 58 is arc-shaped. The first base portion 57 and the second base portion 58 are disposed so as to sandwich the first cylindrical portion 46 of the hammer case 6. A cover 460 is disposed on the upper portion of the first cylindrical portion 46. At least a part of the first base portion 57 overlaps the cover 460. The right end portion of the first base portion 57 and the right end portion of the second base portion 58 are connected via a hinge 59. Each of the left end portion of the first base portion 57 and the left end portion of the second base portion 58 is connected to the handle portion 55. The left end portion of the first base portion 57 and the left end portion of the second base portion 58 are connected via a tightening mechanism 60. The tightening mechanism 60 has a screw 61 disposed in a screw hole provided in the left end portion of the second base portion 58 and a dial portion 62 rotatable with respect to the screw 61. The operator can operate the dial portion 62 to rotate the dial portion 62. When the dial portion 62 rotates, the distance between the left end portion of the first base portion 57 and the left end portion of the second base portion 58 is adjusted. When the screw 61 is rotated so that the distance between the left end portion of the first base portion 57 and the left end portion of the second base portion 58 becomes shorter, the hammer case 6 is tightened to the base portion 56, and the side handle 7 is fixed to the hammer case 6.

[0053] In the embodiment, the handle portion 55 is disposed to the left of the hammer case 6. However, the handle portion 55 can be disposed at any position around the hammer case 6. For example, the handle portion 55 can be disposed to the left of the hammer case 6, above the hammer case 6, or below the hammer case 6. The position (angle) of the handle portion 55 with respect to the hammer case 6 can be adjusted by 360 degrees.

[0054] The bumper 8 is disposed so as to cover at least a part of the surface of the hammer case 6. In the embodiment, the bumper 8 is disposed so as to cover the surface of the first cylindrical portion 46. The bumper 8 protects the hammer case 6. The bumper 8 suppresses contact between the hammer case 6 and an object around the impact tool 1. The bumper 8 is formed of an elastic body that is softer than the hammer case 6. As the elastic body forming the bumper 8, styrene-butadiene rubber is exemplified.

[0055] The battery mounting portion 9 is provided in the battery connection portion 29. The battery pack 63 is mounted on the battery mounting portion 9. A part of the battery connection portion 29 is disposed above the battery pack 63 mounted on the battery mounting portion 9. A part of the battery connection portion 29 is disposed in front of the battery pack 63 mounted on the battery mounting portion 9. The battery pack 63 functions as a power source for the impact tool 1. The battery pack 63 is detachable from the battery mounting portion 9. The battery pack 63 includes a secondary battery. In the embodiment, the battery pack 63 includes a rechargeable lithium-ion battery. By being mounted on the battery mounting portion 9, the battery pack 63 can supply power to the impact tool 1. The motor 10 is driven based on the power supplied from the battery pack 63. The controller 11 operates based on the power supplied from the battery pack 63.

[0056] The battery mounting portion 9 includes a plate-shaped terminal 64. The terminal 64 has a plate made of synthetic resin and a metal connection terminal disposed on the plate. When the battery pack 63 is mounted on the battery mounting portion 9, the connection terminal of the battery pack 63 and the connection terminal of the terminal 64 are connected. The terminal 64 is held by a terminal holder 65. The terminal holder 65 is sandwiched between the left grip housing 3L and the right grip housing 3R. A spring 66 and a buffer member 67 are disposed in a part of the battery connection portion 29 disposed in front of the battery pack 63. The spring 66 is disposed in front of the terminal holder 65. The spring 66 is supported by a part of the battery connection portion 29 disposed in front of the terminal 64. The spring 66 biases the terminal holder 65 rearward. The buffer member 67 is disposed in front of the battery pack 63 mounted on the battery mounting portion 9. The buffer member 67 is supported by a part of the battery connection portion 29 disposed in front of the battery pack 63 mounted on the battery mounting portion 9. Rubber is exemplified as the buffer member 67. The buffer member 67 contacts the front portion of the battery pack 63. For example, when the impact tool 1 drops, the impact acting on the terminal 64 is mitigated by the elastic force of the spring 66, and the impact acting on the battery pack 63 is mitigated by the buffer member 67.

[0057] The motor 10 functions as a power source of the impact tool 1. The motor 10 is an inner-rotor type brushless motor. The motor 10 has a stator 68, a rotor 69, and a rotor shaft 70. The stator 68 is supported by the motor housing 4. At least a part of the rotor 69 is disposed inside the stator 68. The rotor shaft 70 is fixed to the rotor 69. The rotor 69 is rotatable with respect to the stator 68 about a motor rotation axis MX extending in the vertical direction.

[0058] The stator 68 has a stator core 71, an insulator 72, and a coil 73.

[0059] The stator core 71 is disposed radially outside the rotor 69. The stator core 71 includes a plurality of laminated steel plates. The steel plates are metal plates mainly composed of iron. The stator core 71 has a cylindrical yoke and a plurality of teeth protruding radially inward from the inner circumferential surface of the yoke.

[0060] The insulator 72 is an electric insulating member made of synthetic resin. At least a part of the insulator 72 is provided on the upper part of the stator core 71. At least a part of the insulator 72 is provided on the lower part of the stator core 71. At least a part of the insulator 72 is arranged so as to cover the surface of the teeth of the stator core 71.

[0061] The coil 73 is attached to the teeth of the stator core 71 via the insulator 72. The stator core 71 and the coil 73 are electrically insulated by the insulator 72. The plurality of coils 73 are connected via the bus bar unit 74.

[0062] The rotor 69 rotates about the motor rotation axis MX. The rotor 69 has a rotor core 75 and a rotor magnet 76.

[0063] The rotor core 75 includes a plurality of laminated steel plates. The rotor core 75 is cylindrical.

[0064] The rotor magnet 76 is fixed to the rotor core 75. In the embodiment, the rotor magnet 76 is disposed inside the rotor core 75.

[0065] The sensor substrate 77 is fixed to the insulator 72. The sensor substrate 77 detects the position of the rotor 69 in the rotation direction. The sensor substrate 77 has an annular circuit board and a rotation detection element supported by the circuit board. At least a part of the sensor substrate 77 faces the rotor magnet 76. The rotation detection element detects the position of the rotor 69 in the rotation direction by detecting the position of the rotor magnet 76.

[0066] The rotor shaft 70 is disposed inside the rotor core 75. The rotor shaft 70 is fixed to the rotor core 75. The rotor 69 and the rotor shaft 70 rotate together about the motor rotation axis MX. The upper end portion of the rotor shaft 70 protrudes upward from the upper end surface of the rotor core 75. The lower end portion of the rotor shaft 70 protrudes downward from the lower end surface of the rotor core 75.

[0067] The rotor shaft 70 is rotatably supported by each of the rotor bearings 78 and 79. The rotor bearing 78 rotatably supports the upper portion of the rotor shaft 70 disposed above the upper end surface of the rotor core 75. The rotor bearing 79 rotatably supports the lower portion of the rotor shaft 70 disposed below the lower end surface of the rotor core 75. The rotor bearing 78 is held by the gear case 5. The rotor bearing 79 is held by the motor housing 4.

[0068] A first bevel gear 80 is fixed to the upper end portion of the rotor shaft 70. The first bevel gear 80 is connected to at least a part of the speed reduction mechanism 13. The rotor shaft 70 is connected to the speed reduction mechanism 13 via the first bevel gear 80.

[0069] The controller 11 outputs a control signal for controlling the motor 10. The controller 11 includes a circuit board on which a plurality of electronic components are mounted. Examples of the electronic components mounted on the circuit board include a processor such as a CPU (Central Processing Unit), a non-volatile memory such as a ROM (Read Only Memory) or a storage, a volatile memory such as a RAM (Random Access Memory), a field effect transistor (FET), and a resistor.

[0070] The controller 11 is housed in the controller housing portion 28 of the grip housing 3. The controller 11 is held by the controller case 81 in the controller housing portion 28.

[0071] The fan 12 generates an air flow for cooling the motor 10 and the controller 11. The fan 12 is disposed above the stator 68 of the motor 10. The fan 12 is fixed to the upper part of the rotor shaft 70. The fan 12 is disposed between the rotor bearing 78 and the stator core 71. The fan 12 and the rotor shaft 70 rotate together. An air inlet 82 is provided in the lower wall portion 35 of the motor housing 4. Air outlets 83 are provided in the front, left, and right upper parts of the cylindrical portion 34 of the motor housing 4, respectively. Air inlets 84 are provided in the left and right parts of the controller housing portion 28, respectively. When the fan 12 rotates, air in the external space of the motor housing 4 flows into the internal space of the motor housing 4 through the air inlet 82. The air flowing into the internal space of the motor housing 4 cools the motor 10 by flowing through the internal space of the motor housing 4. At least a part of the air that has flowed through the internal space of the motor housing 4 flows out into the external space of the motor housing 4 through the air outlet 83 due to the rotation of the fan 12. Also, when the fan 12 rotates, air in the external space of the grip housing 3 flows into the internal space of the controller housing portion 28 through the air inlet 84. The air flowing into the internal space of the controller housing portion 28 cools the controller 11 by flowing through the internal space of the controller housing portion 28. The air that has flowed through the internal space of the controller housing portion 28 flows out into the external space of the motor housing 4 through the air outlet 83 due to the rotation of the fan 12.

[0072] In an embodiment, a baffle plate 85 is disposed between the fan 12 and the stator 68. The baffle plate 85 guides the air flowing due to the rotation of the fan 12.

[0073] The speed reduction mechanism 13 transmits the rotational force of the motor 10 to the striking mechanism 15 via the spindle 14. The speed reduction mechanism 13 connects the rotor shaft 70 and the spindle 14. The speed reduction mechanism 13 rotates the spindle 14 at a rotational speed lower than the rotational speed of the rotor shaft 70.

[0074] The speed reduction mechanism 13 includes a second bevel gear 86 that meshes with the first bevel gear 80, and a planetary gear mechanism 87 that is driven based on the rotational force of the motor 10 transmitted through the second bevel gear 86.

[0075] The planetary gear mechanism 87 includes a sun gear 88, a plurality of planetary gears 89 arranged around the sun gear 88, and an internal gear 90 arranged around the plurality of planetary gears 89. The planetary gear mechanism 87 is housed in the gear case 5.

[0076] The second bevel gear 86 is arranged around the sun gear 88. The second bevel gear 86 is fixed to the sun gear 88. The second bevel gear 86 and the sun gear 88 rotate together. The second bevel gear 86 and the sun gear 88 are rotatable about an output rotation axis BX extending in the front-rear direction. The output rotation axis BX and the motor rotation axis MX are orthogonal. The rear end portion of the sun gear 88 is supported by a gear bearing 91. The intermediate portion of the sun gear 88 is supported by a gear bearing 92. The gear bearing 91 is held by the bearing cover 44. The gear bearing 92 is held by the gear case 5. When the rotor shaft 70 rotates and the first bevel gear 80 rotates, the second bevel gear 86 rotates. When the second bevel gear 86 rotates, the sun gear 88 rotates.

[0077] Each of the plurality of planetary gears 89 meshes with the sun gear 88. The planetary gear 89 is rotatably supported by a spindle 14 via a pin 93. The spindle 14 is rotated by the planetary gear 89. The internal gear 90 has internal teeth that mesh with the planetary gear 89. The internal gear 90 is fixed to the gear case 5. A plurality of convex portions are provided on the outer peripheral surface of the internal gear 90. The convex portions of the internal gear 90 fit into recesses provided on the inner peripheral surface of the gear case 5. The internal gear 90 is always non-rotatable with respect to the gear case 5.

[0078] When the rotor shaft 70 and the first bevel gear 80 rotate due to the drive of the motor 10, the second bevel gear 86 and the sun gear 88 rotate. When the sun gear 88 rotates, the planetary gear 89 revolves around the sun gear 88. The planetary gear 89 revolves while meshing with the internal teeth of the internal gear 90. Due to the revolution of the planetary gear 89, the spindle 14 connected to the planetary gear 89 via the pin 93 rotates at a rotational speed lower than the rotational speed of the rotor shaft 70.

[0079] The spindle 14 rotates by the rotational force of the motor 10 transmitted by the speed reduction mechanism 13. The spindle 14 transmits the rotational force of the motor 10 transmitted via the speed reduction mechanism 13 to the striking mechanism 15. The spindle 14 is rotatable about the output rotation shaft BX. The rear part of the spindle 14 is housed in the gear case 5. The front part of the spindle 14 is housed in the hammer case 6. At least a part of the spindle 14 is disposed in front of the speed reduction mechanism 13. The spindle 14 is disposed behind the anvil 16.

[0080] The spindle 14 has a flange portion 94, a spindle shaft portion 95 protruding forward from the flange portion 94, and a protruding portion 96 protruding rearward from the flange portion 94. The planetary gear 89 is rotatably supported on each of the flange portion 94 and the protruding portion 96 via the pin 93. The spindle 14 is rotatably supported by the spindle bearing 97. The spindle bearing 97 rotatably supports the protruding portion 96. The spindle bearing 97 is held by the gear case 5.

[0081] The striking mechanism 15 strikes the anvil 16 in the rotational direction about the output rotation shaft BX. The striking mechanism 15 is driven by the motor 10. The striking mechanism 15 is rotatable about the output rotation shaft BX. The rotational force of the motor 10 is transmitted to the striking mechanism 15 via the speed reduction mechanism 13 and the spindle 14. The striking mechanism 15 strikes the anvil 16 in the rotational direction based on the rotational force of the spindle 14 rotated by the motor 10.

[0082] The striking mechanism 15 is accommodated in the first cylindrical portion 46 of the hammer case 6. The striking mechanism 15 includes a hammer 98, a ball 99, a first coil spring 100, a second coil spring 101, a third coil spring 102, a first washer 103, and a second washer 104.

[0083] The hammer 98 is disposed forward of the speed reduction mechanism 13. The hammer 98 is disposed around the spindle 14. The hammer 98 is held by the spindle 14. The ball 99 is disposed between the spindle 14 and the hammer 98. The hammer 98 has a cylindrical hammer body 105 and a hammer protrusion 106 provided at the front portion of the hammer body 105. An annular recess 107 is provided on the rear surface of the hammer body 105. The recess 107 is recessed forward from the rear surface of the hammer body 105.

[0084] The hammer 98 is disposed around the spindle shaft portion 95. The hammer 98 has a hole 108 in which the spindle shaft portion 95 is disposed.

[0085] The hammer 98 is rotated by the motor 10. The rotational force of the motor 10 is transmitted to the hammer 98 via the speed reduction mechanism 13 and the spindle 14. The hammer 98 is rotatable together with the spindle 14 based on the rotational force of the spindle 14 rotated by the motor 10. Each of the hammer 98 and the spindle 14 rotates about the output rotation shaft BX.

[0086] The first washer 103 is disposed inside the recess 107. The first washer 103 is supported by the hammer 98 via a plurality of balls 109. The balls 109 are disposed forward of the first washer 103.

[0087] The second washer 104 is disposed rearward of the first washer 103 inside the recess 107. The outer diameter of the second washer 104 is smaller than the outer diameter of the first washer 103. The second washer 104 and the hammer 98 are relatively movable in the front-rear direction.

[0088] The first coil spring 100 is disposed around the spindle shaft portion 95. The rear end portion of the first coil spring 100 is supported by the flange portion 94. The front end portion of the first coil spring 100 is disposed inside the recess 107 and supported by the first washer 103. The first coil spring 100 constantly generates an elastic force to move the hammer 98 forward.

[0089] The second coil spring 101 is disposed around the spindle shaft portion 95. The second coil spring 101 is disposed radially inside the first coil spring 100. The rear end portion of the second coil spring 101 is supported by the flange portion 94. The front end portion of the second coil spring 101 is disposed inside the recess 107 and supported by the second washer 104. The second coil spring 101 generates an elastic force to move the hammer 98 forward when the hammer 98 moves rearward.

[0090] The third coil spring 102 is disposed around the spindle shaft portion 95. The third coil spring 102 is disposed radially inside the first coil spring 100. The third coil spring 102 is disposed inside the recess 107. The rear end portion of the third coil spring 102 is supported by the second washer 104. The front end portion of the third coil spring 102 is supported by the first washer 103. The third coil spring 102 generates an elastic force to move the second coil spring 101 rearward. Due to the elastic force of the third coil spring 102, the rear end portion of the second coil spring 101 is pressed against the flange portion 94. Thereby, the second coil spring 101 is suppressed from floating with respect to the flange portion 94.

[0091] The ball 99 is made of a metal such as steel. The ball 99 is disposed between the spindle shaft portion 95 and the hammer 98. The spindle 14 has a spindle groove 110 in which at least a part of the ball 99 is disposed. The spindle groove 110 is provided on a part of the outer surface of the spindle shaft portion 95. The hammer 98 has a hammer groove 111 in which at least a part of the ball 99 is disposed. The hammer groove 111 is provided on a part of the inner surface of the hammer 98. The ball 99 is disposed between the spindle groove 110 and the hammer groove 111. The ball 99 can roll inside each of the spindle groove 110 and the hammer groove 111. The hammer 98 is movable along with the ball 99. The spindle 14 and the hammer 98 can move relative to each other in a direction parallel to the output rotation axis BX and in a rotational direction centered on the output rotation axis BX within a movable range defined by the spindle groove 110 and the hammer groove 111.

[0092] The anvil 16 is an output portion of the impact tool 1 that rotates based on the rotational force of the motor 10. At least a part of the anvil 16 is disposed in front of the hammer 98.

[0093] The anvil 16 has an anvil recess 112. The anvil recess 112 is provided at the rear end portion of the anvil 16. The anvil recess 112 is recessed forward from the rear end portion of the anvil 16. The spindle 14 is disposed behind the anvil 16. The front end portion of the spindle shaft portion 95 is disposed in the anvil recess 112.

[0094] The anvil 16 has an anvil shaft portion 113 and an anvil protrusion 114. The anvil shaft portion 113 is disposed in front of the striking mechanism 15. The anvil protrusion 114 protrudes radially outward from the rear end portion of the anvil shaft portion 113. The anvil protrusion 114 is struck in a rotational direction centered on the output rotation axis BX by the striking mechanism 15.

[0095] The front end portion of the anvil shaft portion 113 is disposed in front of the hammer case 6 through the opening 49. A socket is attached as a tip tool to the front end portion of the anvil shaft portion 113.

[0096] The anvil 16 is rotatably supported by an anvil bearing 115. The anvil bearing 115 is disposed around the anvil shaft portion 113. The anvil 16 is rotatable about the output rotation shaft BX. The anvil bearing 115 is held by the hammer case 6. The anvil bearing 115 is disposed inside the second cylindrical portion 47 of the hammer case 6. The anvil bearing 115 is held by the second cylindrical portion 47 of the hammer case 6.

[0097] The trigger switch 17 is operated by an operator to drive the motor 10. Driving the motor 10 means that the coil 73 of the stator 68 is energized and the rotor 69 rotates. The trigger switch 17 is provided at the upper part of the rear grip portion 31. The trigger switch 17 includes a trigger lever 116 and a switch body 117. The switch body 117 is disposed in the internal space of the rear grip portion 31. The trigger lever 116 protrudes forward from the upper part of the front portion of the rear grip portion 31. The trigger lever 116 is operated by the operator to move rearward. When the trigger lever 116 is operated to move rearward, the motor 10 is driven. When the operation of the trigger lever 116 is released, the driving of the motor 10 stops.

[0098] The light assembly 18 emits illumination light. The light assembly 18 illuminates the anvil 16 and the periphery of the anvil 16 with the illumination light. The light assembly 18 illuminates the front of the anvil 16 with the illumination light. Further, the light assembly 18 illuminates the socket mounted on the anvil 16 and the periphery of the socket with the illumination light. In the embodiment, the light assembly 18 includes a circuit board 118, a light-emitting element 119 mounted on the front surface of the circuit board 118, and a ring-shaped light cover 120 disposed forward of the circuit board 118. The light cover 120 is disposed so as to cover the light-emitting element 119. The light assembly 18 is disposed around the second cylindrical portion 47 of the hammer case 6. A ring spring 181 is disposed in front of the light assembly 18 to prevent the light assembly 18 from coming out forward from the second cylindrical portion 47.

[0099] [Restraining member] FIG. 11 is a cross-sectional view showing a part of the impact tool 1 according to the embodiment, and corresponds to an enlarged view of a part of FIG. 9. FIG. 12 is a cross-sectional view showing a part of the impact tool 1 according to the embodiment, and corresponds to an enlarged view of a part of FIG. 10.

[0100] In FIGS. 11 and 12, the direction parallel to the output rotation axis BX is appropriately referred to as the axial direction, the direction around the output rotation axis BX is appropriately referred to as the circumferential direction or the rotational direction, and the radial direction of the output rotation axis BX is appropriately referred to as the radial direction. Further, in the radial direction, a position close to the output rotation axis BX or a direction approaching it is appropriately referred to as the inner radial side, and a position far from the output rotation axis BX or a direction separating from it is appropriately referred to as the outer radial side.

[0101] In a cross-section orthogonal to the output rotation axis BX, the shape of the outer peripheral surface of the anvil shaft portion 113 is circular. In a cross-section orthogonal to the output rotation axis BX, the shape of the inner peripheral surface of the anvil bearing 115 is circular.

[0102] As shown in FIGS. 11 and 12, a first groove portion 121 is formed on the outer peripheral surface of the anvil shaft portion 113. The first groove portion 121 is formed on the outer peripheral surface of the anvil shaft portion 113 so as to surround the output rotation axis BX.

[0103] A second groove portion 122 is formed on the inner peripheral surface of the anvil bearing 115. The second groove portion 122 is formed on the inner peripheral surface of the anvil bearing 115 so as to surround the output rotation axis BX.

[0104] In the embodiment, the anvil bearing 115 is a sliding bearing. The second groove portion 122 is formed on the inner peripheral surface of the sliding bearing. The anvil bearing 115 is cylindrical. In the embodiment, a sleeve is used as the anvil bearing 115. Note that, for example, a sliding bearing may be formed by impregnating a cylindrical porous metal body manufactured by a powder metallurgy method with lubricating oil.

[0105] The impact tool 1 includes a restraining member 123 that suppresses the anvil shaft portion 113 from coming out forward from the hammer case 6. The restraining member 123 includes a first portion 124 disposed in the first groove portion 121 and a second portion 125 disposed in the second groove portion 122. The first portion 124 is a part of the restraining member 123 on the radially inner side. The second portion 125 is a part of the restraining member 123 on the radially outer side than the first portion 124.

[0106] The restraining member 123 is in a ring shape surrounding the output rotation shaft BX. In the embodiment, the restraining member 123 is an O-ring that contacts the inner surfaces of the first groove portion 121 and the second groove portion 122, respectively.

[0107] The inner surface of the first groove portion 121 includes a first front surface 126, a first rear surface 127, and a first circumferential surface 128. The first front surface 126 faces rearward. The first rear surface 127 is disposed rearward of the first front surface 126. The first rear surface 127 faces forward. The first circumferential surface 128 is connected to each of the radially inner end portions of the first front surface 126 and the first rear surface 127. The first circumferential surface 128 faces radially outward.

[0108] The inner surface of the second groove portion 122 includes a second front surface 129, a second rear surface 130, and a second circumferential surface 131. The second front surface 129 faces rearward. The second rear surface 130 is disposed rearward of the second front surface 129. The second rear surface 130 faces forward. The second circumferential surface 131 is connected to each of the radially outer end portions of the second front surface 129 and the second rear surface 130. The second circumferential surface 131 faces radially inward.

[0109] In the embodiment, the depth of the first groove portion 121 and the depth of the second groove portion 122 are substantially equal. Note that the depth of the first groove portion 121 may be deeper than the depth of the second groove portion 122, or the depth of the second groove portion 122 may be deeper than the depth of the first groove portion 121. The depth of the first groove portion 121 refers to the dimension of the first groove portion 121 in the radial direction. That is, the depth of the first groove portion 121 refers to the distance between the outer peripheral surface of the anvil shaft portion 113 and the first peripheral surface 128 in the radial direction. The depth of the second groove portion 122 refers to the dimension of the second groove portion 122 in the radial direction. That is, the depth of the second groove portion 122 refers to the distance between the inner peripheral surface of the anvil bearing 115 and the second peripheral surface 131 in the radial direction.

[0110] The dimension of the first groove portion 121 in the axial direction is shorter than the dimension of the second groove portion 122 in the axial direction. The dimension of the first groove portion 121 in the axial direction refers to the distance between the first front surface 126 and the first rear surface 127. The dimension of the second groove portion 122 in the axial direction refers to the distance between the second front surface 129 and the second rear surface 130. In the examples shown in FIGS. 11 and 12, the positions of the first front surface 126 and the second front surface 129 in the axial direction are substantially equal. The first rear surface 127 is disposed in front of the second rear surface 130.

[0111] Note that the positions of the first front surface 126 and the second front surface 129 in the axial direction may be different. The first rear surface 127 may not be disposed in front of the second rear surface 130, and may be disposed behind the second rear surface 130.

[0112] The suppression member 123 is disposed so as to contact each of the first peripheral surface 128 and the second peripheral surface 131. As described above, in the embodiment, the suppression member 123 is an O-ring. The suppression member 123 is slightly crushed by the first peripheral surface 128 and the second peripheral surface 131. The suppression member 123 seals the boundary between the first peripheral surface 128 and the second peripheral surface 131.

[0113] In the examples shown in FIGS. 11 and 12, the suppression member 123 is arranged to contact each of the first front surface 126 and the second front surface 129. The suppression member 123 seals the boundary between the anvil shaft portion 113 and the anvil bearing 115.

[0114] The hammer case 6 has a bearing support surface 132 that contacts the front end portion of the anvil bearing 115. The bearing support surface 132 is provided at the front end portion of the second cylindrical portion 47. The bearing support surface 132 faces rearward. The bearing support surface 132 presses the anvil bearing 115 from the front. The bearing support surface 132 suppresses the anvil bearing 115 from coming out forward from the hammer case 6. In a plane orthogonal to the output rotation shaft BX, the bearing support surface 132 is ring-shaped. The opening 49 is defined radially inward of the bearing support surface 132.

[0115] The front end portion of the anvil shaft portion 113 is disposed forward of the second cylindrical portion 47 through the opening 49. At least a part of the anvil shaft portion 113 is disposed inside the opening 49. A seal member 133 is provided at the front end portion of the second cylindrical portion 47. The seal member 133 is disposed inside the opening 49. The seal member 133 seals the boundary between the front end portion of the second cylindrical portion 47 and the anvil shaft portion 113. The seal member 133 is disposed forward of the suppression member 123.

[0116] The anvil shaft portion 113 has a break starting portion 134 disposed rearward of the first groove portion 121. The sectional modulus of the anvil shaft portion 113 at the break starting portion 134 is smaller than the sectional modulus of the anvil shaft portion 113 at the first groove portion 121. That is, the sectional modulus of the anvil shaft portion 113 passing through the break starting portion 134 and orthogonal to the output rotation shaft BX is smaller than the sectional modulus of the anvil shaft portion 113 passing through the first groove portion 121 and orthogonal to the output rotation shaft BX. In the anvil shaft portion 113, the break starting portion 134 is the portion with the lowest strength against bending moment. That is, in the anvil shaft portion 113, the break starting portion 134 is the portion most likely to break when a high load acts on the anvil shaft portion 113.

[0117] A third groove portion 135 is formed on the outer peripheral surface of the anvil shaft portion 113. The third groove portion 135 is formed behind the first groove portion 121. The third groove portion 135 is formed on the outer peripheral surface of the anvil shaft portion 113 so as to surround the output rotating shaft BX.

[0118] The depth of the third groove portion 135 is deeper than the depth of the first groove portion 121. The depth of the third groove portion 135 refers to the dimension of the third groove portion 135 in the radial direction. The diameter Db of the anvil shaft portion 113 in the third groove portion 135 is smaller than the diameter Da of the anvil shaft portion 113 in the first groove portion 121. The breakage starting portion 134 includes the anvil shaft portion 113 in the third groove portion 135. In the axial direction, a large-diameter portion 136 of the anvil shaft portion 113 having a diameter larger than the diameters Da and Db is provided between the first groove portion 121 and the third groove portion 135. A first rear side surface 127 is disposed at the front portion of the large-diameter portion 136.

[0119] FIG. 13 is a cross-sectional view showing a state in which a part of the anvil shaft portion 113 according to the embodiment is broken. For example, when a high load acts on the anvil shaft portion 113 during a fastening operation, at least a part of the anvil shaft portion 113 may be broken. In the embodiment, a breakage starting portion 134 is provided on the anvil shaft portion 113. Therefore, when a high load acts on the anvil shaft portion 113, as shown in FIG. 13, the anvil shaft portion 113 breaks at the breakage starting portion 134.

[0120] When the anvil shaft portion 113 breaks at the breakage starting portion 134, the anvil shaft portion 113 in front of the breakage starting portion 134 may move forward with respect to the hammer case 6. When the anvil shaft portion 113 moves forward, the first rear side surface 127 of the first groove portion 121 is caught by the suppression member 123.

[0121] The front end of the anvil bearing 115 contacts the bearing support surface 132 of the hammer case 6. Even if the anvil shaft portion 113 breaks, the anvil bearing 115 does not move forward with respect to the hammer case 6. The restraining member 123 is supported by the second front side surface 129 of the second groove portion 122. The restraining member 123 supported by the second front side surface 129 of the anvil bearing 115 also does not move forward with respect to the hammer case 6. As shown in FIG. 13, in a state where the anvil shaft portion 113 has broken at the break starting point portion 134, the restraining member 123 contacts each of the first rear side surface 127 and the second front side surface 129. The anvil shaft portion 113 catches on the restraining member 123 that does not move forward with respect to the hammer case 6. Therefore, when the anvil shaft portion 113 breaks at the break starting point portion 134, the anvil shaft portion 113 is prevented from coming off forward from the hammer case 6. That is, when the anvil shaft portion 113 breaks, the anvil shaft portion 113 in front of the break starting point portion 134 is prevented from falling off from the impact tool 1.

[0122] [Vibration isolation mechanism] FIG. 14 is a cross-sectional view showing a part of the impact tool 1 according to the embodiment, and corresponds to a cross-sectional view taken along the line C-C in FIG. 9 as viewed in the arrow direction. FIG. 15 is a cross-sectional view showing a part of the impact tool 1 according to the embodiment, and corresponds to a cross-sectional view taken along the line D-D in FIG. 14 as viewed in the arrow direction. FIG. 16 is a cross-sectional view showing a part of the impact tool 1 according to the embodiment, and corresponds to a view of the cross-section along the line E'-E' in FIG. 14 as viewed from above (in the E direction). FIG. 17 is an exploded perspective view showing a part of the impact tool 1 according to the embodiment. FIG. 18 is an exploded perspective view showing a part of the impact tool 1 according to the embodiment.

[0123] As shown in FIGS. 14, 15, 16, 17, and 18, the impact tool 1 has a vibration damping mechanism 137. The vibration damping mechanism 137 suppresses the transmission of vibrations of the hammer case 6 to the grip housing 3 via the main body housing 2. Due to at least one of the rotation of the anvil 16 during fastening work, the impact on the anvil 16 by the striking mechanism 15, and the load received by the anvil 16 from the work object, vibrations may occur in the hammer case 6. If the vibrations of the hammer case 6 are transmitted to the grip housing 3 via the main body housing 2 and the grip housing 3 vibrates, the workability of the fastening work may decrease, or discomfort may be given to the operator holding the grip housing 3. By suppressing the transmission of vibrations of the hammer case 6 to the grip housing 3 by the vibration damping mechanism 137, a decrease in the workability of the fastening work and giving discomfort to the operator holding the grip housing 3 are suppressed. Further, in the embodiment, the controller 11 is housed in the controller housing portion 28 of the grip housing 3. If the controller 11 vibrates, malfunction of the controller 11 may occur. By suppressing the transmission of vibrations of the hammer case 6 to the grip housing 3 by the vibration damping mechanism 137, vibration of the controller 11 is suppressed.

[0124] The vibration damping mechanism 137 includes vibration damping members 138 and 139 disposed between the main body housing 2 and the grip housing 3. Each of the vibration damping members 138 and 139 suppresses the transmission of vibrations of the hammer case 6 to the grip housing 3 via the main body housing 2.

[0125] As described above, the main body housing 2 has a main body portion 20 and a protruding portion 21 protruding rearward from the main body portion 20. The grip housing 3 has a connecting portion 30 connected to the protruding portion 21. Each of the vibration damping members 138 and 139 is disposed between the protruding portion 21 and the connecting portion 30.

[0126] As shown in FIGS. 14 and 15, in the protruding portion 21, the left main body housing 2L and the right main body housing 2R are fixed by screws 190.

[0127] The vibration damping member 138 is a first vibration damping member that suppresses the vibration of the hammer case 6 in the axial direction parallel to the output rotation shaft BX from being transmitted to the grip housing 3 via the main body housing 2. The vibration damping member 138 includes rubber. In the embodiment, the vibration damping member 138 is a cushion rubber.

[0128] The vibration damping member 139 is a second vibration damping member that suppresses the vibration of the hammer case 6 in the rotational direction about the output rotation shaft BX from being transmitted to the grip housing 3 via the main body housing 2. The vibration damping member 139 includes a spring. In the embodiment, the vibration damping member 139 is a compression spring.

[0129] As shown in FIGS. 17 and 18, the outer shape of the protruding portion 21 is substantially cylindrical. The protruding portion 21 has an outer peripheral surface 140 arranged to surround a virtual axis CX parallel to the output rotation shaft BX, and a groove portion 141 formed in at least a part of the outer peripheral surface 140. The opening 40A is provided in the protruding portion 21.

[0130] As shown in FIGS. 14, 16, 17, and 18, a plurality of groove portions 141 are provided on the outer peripheral surface 140. In the embodiment, four groove portions 141 are provided on the outer peripheral surface 140. In the following description, the groove portion 141 provided at the upper left with respect to the virtual axis CX is appropriately referred to as the groove portion 141A, the groove portion 141 provided at the lower left with respect to the virtual axis CX is appropriately referred to as the groove portion 141B, the groove portion 141 provided at the upper right with respect to the virtual axis CX is appropriately referred to as the groove portion 141C, and the groove portion 141 provided at the lower right with respect to the virtual axis CX is appropriately referred to as the groove portion 141D.

[0131] The groove portions 141 (141A, 141B, 141C, 141D) are formed to extend in the circumferential direction around the virtual axis CX. In a plane orthogonal to the virtual axis CX, the groove portions 141 are formed in an arc shape.

[0132] Also, as shown in FIGS. 14, 15, 17, and 18, the protruding portion 21 has a recess 142 formed adjacent to the groove portion 141 on the outer peripheral surface 140. A plurality of recesses 142 are provided on the outer peripheral surface 140. In the embodiment, two recesses 142 are provided on the outer peripheral surface 140. In the following description, the recess 142 provided to the left of the virtual axis CX is appropriately referred to as the recess 142A, and the recess 142 provided to the right of the virtual axis CX is appropriately referred to as the recess 142B.

[0133] The recess 142 is formed between a first groove portion 141 and a second groove portion 141 that are adjacent to each other among the plurality of groove portions 141. In the embodiment, the recess 142A is provided between the groove portion 141A and the groove portion 141B disposed adjacent to the groove portion 141A. The groove portion 141B is provided below the groove portion 141A. The recess 142B is provided between the groove portion 141C and the groove portion 141D disposed adjacent to the groove portion 141C. The groove portion 141D is provided below the groove portion 141C.

[0134] The recess 142 (142A, 142B) is formed to extend in the vertical direction.

[0135] The space inside the recess 142A is connected to the space inside the groove portion 141A and the space inside the groove portion 141B respectively. The space inside the recess 142B is connected to the space inside the groove portion 141C and the space inside the groove portion 141D respectively.

[0136] As shown in FIGS. 14 and 18, a partition wall 151 is provided between the upper end portions of the groove portion 141A and the groove portion 141C. A partition wall 152 is provided between the lower end portions of the groove portion 141B and the groove portion 141D.

[0137] A partition wall 155 is provided between the lower end of the groove portion 141C and the upper end of the recessed portion 142B. The space inside the groove portion 141C and the space inside the recessed portion 142B are connected via a notch portion 165 provided in the partition wall 155. A partition wall 156 is provided between the upper end of the groove portion 141D and the lower end of the recessed portion 142B. The space inside the groove portion 141D and the space inside the recessed portion 142B are connected via a notch portion 166 provided in the partition wall 156. Similarly, a partition wall 153 is provided between the lower end of the groove portion 141A and the upper end of the recessed portion 142A. The space inside the groove portion 141A and the space inside the recessed portion 142A are connected via a notch portion 163 provided in the partition wall 153. A partition wall 154 is provided between the upper end of the groove portion 141B and the lower end of the recessed portion 142A. The space inside the groove portion 141B and the space inside the recessed portion 142A are connected via a notch portion 164 provided in the partition wall 154.

[0138] As shown in FIGS. 14 and 17, a convex portion 143 is provided on the inner surface of the connecting portion 30 of the grip housing 3.

[0139] The convex portion 143 provided on the connecting portion 30 of the grip housing 3 is arranged in the groove portion 141 provided on the protruding portion 21 of the main body housing 2. A plurality of convex portions 143 are provided so as to be arranged in each of the plurality of groove portions 141. In the embodiment, four convex portions 143 are provided on the inner surface of the connecting portion 30. In the following description, the convex portion 143 arranged in the groove portion 141A is appropriately referred to as the convex portion 143A, the convex portion 143 arranged in the groove portion 141B is appropriately referred to as the convex portion 143B, the convex portion 143 arranged in the groove portion 141C is appropriately referred to as the convex portion 143C, and the convex portion 143 arranged in the groove portion 141D is appropriately referred to as the convex portion 143D.

[0140] The convex portions 143 (143A, 143B, 143C, 143D) are formed so as to extend in the circumferential direction around the virtual axis CX. In a plane orthogonal to the virtual axis CX, the convex portion 143 is formed in an arc shape.

[0141] As shown in FIGS. 14, 16, 17, and 18, the vibration isolation member 138 is disposed in the groove portion 141. The vibration isolation member 138 is disposed in each of the plurality of groove portions 141. In the embodiment, four vibration isolation members 138 are provided. In the following description, the vibration isolation member 138 disposed in the groove portion 141A is appropriately referred to as the vibration isolation member 138A, the vibration isolation member 138 disposed in the groove portion 141B is appropriately referred to as the vibration isolation member 138B, the vibration isolation member 138 disposed in the groove portion 141C is appropriately referred to as the vibration isolation member 138C, and the vibration isolation member 138 disposed in the groove portion 141D is appropriately referred to as the vibration isolation member 138D.

[0142] The vibration isolation members 138 (138A, 138B, 138C, 138D) extend in the circumferential direction centered on the virtual axis CX. In the plane orthogonal to the virtual axis CX, the vibration isolation member 138 is arc-shaped.

[0143] As shown in FIGS. 14, 15, 17, and 18, the vibration isolation member 139 is disposed in the recess portion 142. The vibration isolation member 139 is disposed in each of the plurality of recess portions 142. In the embodiment, two vibration isolation members 139 are provided. In the following description, the vibration isolation member 139 disposed in the recess portion 142A is appropriately referred to as the vibration isolation member 139A, and the vibration isolation member 139 disposed in the recess portion 142B is appropriately referred to as the vibration isolation member 139B.

[0144] The vibration isolation members 139 (139A, 139B) extend in the vertical direction. The vibration isolation member 139 has an upper end portion and a lower end portion.

[0145] The vibration isolation member 139 is disposed in the recess portion 142 so as to expand and contract in the rotational direction (vertical direction). The vibration isolation member 139 is elastically deformed at least in the rotational direction.

[0146] The inner surface of the groove portion 141 includes a first support surface 144, a second support surface 145, and a peripheral surface 146. The first support surface 144 faces rearward. The second support surface 145 is disposed rearward of the first support surface 144. The second support surface 145 faces forward. The peripheral surface 146 is connected to each of the radially inner end of the first support surface 144 and the radially inner end of the second support surface 145. The peripheral surface 146 faces radially outward.

[0147] The vibration isolator 138 includes a first vibration isolation portion 147 supported by the first support surface 144, a second vibration isolation portion 148 supported by the second support surface 145, and a third vibration isolation portion 149 supported by the peripheral surface 146. The first vibration isolation portion 147 elastically deforms at least in the axial direction (front-rear direction). The second vibration isolation portion 148 elastically deforms at least in the axial direction (front-rear direction). The first vibration isolation portion 147 contacts the first support surface 144. The second vibration isolation portion 148 contacts the second support surface 145. The third vibration isolation portion 149 contacts the peripheral surface 146.

[0148] The first vibration isolation portion 147 and the second vibration isolation portion 148 are arranged in the front-rear direction. The second vibration isolation portion 148 is disposed rearward of the first vibration isolation portion 147. The first vibration isolation portion 147 and the second vibration isolation portion 148 face each other with a gap therebetween.

[0149] The convex portion 143 of the grip housing 3 is disposed between the first vibration isolation portion 147 and the second vibration isolation portion 148. The convex portion 143A is disposed between the first vibration isolation portion 147 and the second vibration isolation portion 148 of the vibration isolator 138A. The convex portion 143B is disposed between the first vibration isolation portion 147 and the second vibration isolation portion 148 of the vibration isolator 138B. The convex portion 143C is disposed between the first vibration isolation portion 147 and the second vibration isolation portion 148 of the vibration isolator 138C. The convex portion 143D is disposed between the first vibration isolation portion 147 and the second vibration isolation portion 148 of the vibration isolator 138D.

[0150] The front surface of the convex portion 143 contacts the first vibration isolation portion 147. The rear surface of the convex portion 143 contacts the second vibration isolation portion 148. The radially inner surface of the convex portion 143 contacts the third vibration isolation portion 149.

[0151] Further, at least a part of the convex portion 143 contacts the end portion of the vibration isolator 139 disposed in the concave portion 142. The end portion of the convex portion 143 in the rotational direction contacts the end portion of the vibration isolator 139 disposed in the concave portion 142.

[0152] The lower end portion of the convex portion 143A disposed in the groove portion 141A contacts the upper end portion, which is one end portion of the vibration isolator 139A disposed in the concave portion 142A, via the notch portion 163 formed in the partition wall 153 at the lower end portion of the groove portion 141A. The upper end portion of the vibration isolator 139A contacts the lower end portion of the convex portion 143A in a state of entering the inside of the notch portion 163. The upper end portion of the convex portion 143A disposed in the groove portion 141A is separated from the partition wall 151 at the upper end portion of the groove portion 141A. When the grip housing 3 rotates with respect to the main body housing 2, the upper end portion of the convex portion 143A contacts the partition wall 151.

[0153] The upper end portion of the convex portion 143B disposed in the groove portion 141B contacts the lower end portion, which is the other end portion of the vibration isolator 139A disposed in the concave portion 142A, via the notch portion 164 formed in the partition wall 154 at the upper end portion of the groove portion 141B. The lower end portion of the vibration isolator 139A contacts the upper end portion of the convex portion 143B in a state of entering the inside of the notch portion 164. The lower end portion of the convex portion 143B disposed in the groove portion 141B is separated from the partition wall 152 at the lower end portion of the groove portion 141B. When the grip housing 3 rotates with respect to the main body housing 2, the lower end portion of the convex portion 143B contacts the partition wall 152.

[0154] The vibration isolator 139A is sandwiched between the lower end portion of the convex portion 143A and the upper end portion of the convex portion 143B.

[0155] The lower end of the convex portion 143C disposed in the groove portion 141C contacts the upper end, which is one end of the vibration isolator 139B disposed in the recess portion 142B, via the notch portion 165 formed in the partition wall 155 at the lower end of the groove portion 141C. The upper end of the vibration isolator 139B contacts the lower end of the convex portion 143C in a state of entering the inside of the notch portion 165. The upper end of the convex portion 143C disposed in the groove portion 141C is separated from the partition wall 151 at the upper end of the groove portion 141C. When the grip housing 3 rotates with respect to the main body housing 2, the upper end of the convex portion 143C contacts the partition wall 151.

[0156] The upper end of the convex portion 143D disposed in the groove portion 141D contacts the lower end, which is the other end of the vibration isolator 139B disposed in the recess portion 142B, via the notch portion 166 formed in the partition wall 156 at the upper end of the groove portion 141D. The lower end of the vibration isolator 139B contacts the upper end of the convex portion 143D in a state of entering the inside of the notch portion 166. The lower end of the convex portion 143D disposed in the groove portion 141D is separated from the partition wall 152 at the lower end of the groove portion 141D. When the grip housing 3 rotates with respect to the main body housing 2, the lower end of the convex portion 143D contacts the partition wall 152.

[0157] The vibration isolator 139B is sandwiched between the lower end of the convex portion 143C and the upper end of the convex portion 143D.

[0158] When the hammer case 6 vibrates in the axial direction parallel to the output rotation shaft BX, the vibration transmitted from the hammer case 6 to the grip housing 3 through the main body housing 2 is attenuated by the elastic deformation of the first vibration isolator 147 that contacts the front surface of the convex portion 143 and the second vibration isolator 148 that contacts the rear surface of the convex portion 143. That is, the elastic deformation of the vibration isolator 138 in the axial direction suppresses the transmission of the vibration of the hammer case 6 in the axial direction parallel to the output rotation shaft BX to the grip housing 3.

[0159] When the hammer case 6 vibrates in the rotational direction about the output rotation axis BX, the vibration transmitted from the hammer case 6 to the grip housing 3 via the main body housing 2 is attenuated by the elastic deformation of the vibration isolation member 139 that contacts the end portion in the rotational direction of the convex portion 143. That is, the elastic deformation of the vibration isolation member 139 in the rotational direction suppresses the transmission of the vibration of the hammer case 6 in the rotational direction about the output rotation axis BX to the grip housing 3.

[0160] [Operation of Impact Tool] Next, the operation of the impact tool 1 will be described. For example, when performing a fastening operation on a work target, a socket used for the fastening operation is attached to the front end portion of the anvil 16. After the socket is attached to the anvil 16, the operator holds the side handle 7 with the left hand and the grip portion 27 with the right hand, and operates the trigger lever 116 with the index finger and middle finger of the right hand so that the trigger lever 116 moves rearward. When the trigger lever 116 is operated to move rearward, power is supplied from the battery pack 63 to the motor 10, the motor 10 is driven, and the light assembly 18 lights up. By driving the motor 10, the rotor 69 and the rotor shaft 70 rotate. When the rotor shaft 70 rotates, the rotational force of the rotor shaft 70 is transmitted to the planetary gear 89 via the first bevel gear 80, the second bevel gear 86, and the sun gear 88. The planetary gear 89 revolves around the sun gear 88 while rotating in a state of meshing with the internal teeth of the internal gear 90. The planetary gear 89 is rotatably supported by the spindle 14 via a pin 93. Due to the revolution of the planetary gear 89, the spindle 14 rotates at a rotational speed lower than the rotational speed of the rotor shaft 70.

[0161] When the spindle 14 rotates with the hammer protrusion 106 and the anvil protrusion 114 in contact, the anvil 16 rotates together with the hammer 98 and the spindle 14. As the anvil 16 rotates, the fastening operation proceeds.

[0162] When a load equal to or greater than a predetermined value acts on the anvil 16 as the fastening operation progresses, the rotation of the anvil 16 and the hammer 98 stops. When the spindle 14 rotates while the hammer 98 is stopped, the hammer 98 moves rearward. When the hammer 98 moves rearward, the contact between the hammer protrusion 106 and the anvil protrusion 114 is released. The rearward-moved hammer 98 moves forward while rotating by the elastic forces of the first coil spring 100 and the second coil spring 101. When the hammer 98 moves forward while rotating, the anvil 16 is struck in the rotational direction by the hammer 98. As a result, the anvil 16 rotates about the output rotation shaft BX with high torque. Therefore, the bolt or nut is tightened with high torque.

[0163] When a high load acts on the anvil shaft portion 113 during the fastening operation, at least a part of the anvil shaft portion 113 may break. In the embodiment, a break starting portion 134 is provided on the anvil shaft portion 113. Therefore, when a high load acts on the anvil shaft portion 113, as described with reference to FIG. 13, the anvil shaft portion 113 breaks at the break starting portion 134. When the anvil shaft portion 113 breaks at the break starting portion 134 and the anvil shaft portion 113 in front of the break starting portion 134 moves forward with respect to the hammer case 6, the first rear surface 127 of the first groove portion 121 is caught by the suppressing member 123. Therefore, the anvil shaft portion 113 in front of the break starting portion 134 is suppressed from falling off the impact tool 1.

[0164] Vibration of the hammer case 6 generated during the fastening operation is attenuated by the vibration damping mechanism 137. Thereby, transmission of the vibration of the hammer case 6 to the grip housing 3 via the main body housing 2 is suppressed. Therefore, it is suppressed that the workability of the fastening operation deteriorates or that discomfort is given to the operator holding the grip housing 3. Vibration of the controller 11 housed in the controller housing portion 28 of the grip housing 3 is suppressed. Therefore, occurrence of malfunction of the controller 11 is suppressed.

[0165] [Effect] As described above, according to the embodiment, the impact tool 1 includes a motor 10, a striking mechanism 15 driven by the motor 10, an anvil 16 struck in the rotational direction by the striking mechanism 15, a hammer case 6 that houses the striking mechanism 15, and an anvil bearing 115. The striking mechanism 15 is rotatable about an output rotation axis BX extending in the front-rear direction. The anvil 16 has an anvil shaft portion 113 disposed forward of the striking mechanism 15 and an anvil protrusion portion 114 protruding radially outward from the rear end portion of the anvil shaft portion 113. The anvil protrusion portion 114 is struck in the rotational direction about the output rotation axis BX by the striking mechanism 15. The anvil bearing 115 is held by the hammer case 6 and disposed around the anvil shaft portion 113. A first groove portion 121 is formed on the outer peripheral surface of the anvil shaft portion 113 so as to surround the output rotation axis BX. A second groove portion 122 is formed on the inner peripheral surface of the anvil bearing 115 so as to surround the output rotation axis BX. The impact tool 1 includes a restraining member 123 including a first portion 124 disposed in the first groove portion 121 and a second portion 125 disposed in the second groove portion 122.

[0166] In the above configuration, since the restraining member 123 including the first portion 124 disposed in the first groove portion 121 and the second portion 125 disposed in the second groove portion 122 is provided, when at least a part of the anvil shaft portion 113 is damaged, the anvil shaft portion 113 catches on the restraining member 123 supported by the second groove portion 122. Therefore, the anvil shaft portion 113 is prevented from coming out forward from the hammer case 6. Accordingly, the detachment of the anvil 16 from the impact tool 1 is suppressed.

[0167] In the embodiment, the restraining member 123 is ring-shaped and surrounds the output rotation axis BX.

[0168] In the above configuration, when at least a part of the anvil shaft portion 113 is damaged, the anvil shaft portion 113 can be sufficiently caught on the restraining member 123 supported by the second groove portion 122.

[0169] In an embodiment, the suppression member 123 is an O-ring that contacts each of the inner surfaces of the first groove portion 121 and the second groove portion 122.

[0170] In the above configuration, the boundary between the inner surface of the first groove portion 121 and the inner surface of the second groove portion 122 is sealed by the O-ring. Therefore, for example, grease supplied to the striking mechanism 15 is suppressed from leaking from the boundary between the inner surface of the first groove portion 121 and the inner surface of the second groove portion 122.

[0171] In an embodiment, the anvil shaft portion 113 has a break starting portion 134 with a sectional modulus smaller than the sectional modulus of the anvil shaft portion 113 in the first groove portion 121. The break starting portion 134 is disposed rearward of the first groove portion 121.

[0172] In the above configuration, when a high load acts on the anvil shaft portion 113, the anvil shaft portion 113 breaks at the break starting portion 134. Since the anvil shaft portion 113 breaks rearward of the first groove portion 121, the first groove portion 121 of the anvil shaft portion 113 can be caught by the suppression member 123 supported by the second groove portion 122.

[0173] In an embodiment, the impact tool 1 includes a third groove portion 135 formed on the outer peripheral surface of the anvil shaft portion 113 so as to surround the output rotation shaft BX rearward of the first groove portion 121. The diameter Db of the anvil shaft portion 113 in the third groove portion 135 is smaller than the diameter Da of the anvil shaft portion 113 in the first groove portion 121. The break starting portion 134 includes the anvil shaft portion 113 in the third groove portion 135.

[0174] In the above configuration, by forming the third groove portion 135, the break starting portion 134 is easily formed.

[0175] In the embodiment, the inner surface of the first groove portion 121 includes a first front side surface 126 facing rearward, a first rear side surface 127 disposed rearward of the first front side surface 126 and facing forward, and a first circumferential surface 128 connected to each of the radially inner end of the first front side surface 126 and the radially inner end of the first rear side surface 127 and facing radially outward. The inner surface of the second groove portion 122 includes a second front side surface 129 facing rearward and a second circumferential surface 131 connected to the radially outer end of the second front side surface 129 and facing radially inward.

[0176] In the above configuration, since each of the first groove portion 121 and the second groove portion 122 is properly formed, when the anvil shaft portion 113 breaks at the break starting portion 134, the first groove portion 121 of the anvil shaft portion 113 can be caught by the restraining member 123 supported by the second groove portion 122.

[0177] In the embodiment, in a state where the anvil shaft portion 113 breaks at the break starting portion 134, the restraining member 123 contacts each of the first rear side surface 127 and the second front side surface 129.

[0178] In the above configuration, when the anvil shaft portion 113 breaks at the break starting portion 134, the first rear side surface 127 of the first groove portion 121 is caught by the restraining member 123 supported by the second front side surface 129 of the second groove portion 122, so that the anvil shaft portion 113 is prevented from coming out forward from the hammer case 6.

[0179] In the embodiment, the hammer case 6 has a bearing support surface 132 that contacts the front end portion of the anvil bearing 115.

[0180] In the above configuration, since the front end portion of the anvil bearing 115 contacts the bearing support surface 132 of the hammer case 6, the anvil bearing 115 is prevented from coming off forward from the hammer case 6. Even if the anvil shaft portion 113 is broken, the anvil bearing 115 does not come off forward from the hammer case 6, so the restraining member 123 supported by the second groove portion 122 of the anvil bearing 115 also does not come off forward from the hammer case 6. Therefore, when at least a part of the anvil shaft portion 113 is broken, the anvil shaft portion 113 is caught by the restraining member 123 supported by the second groove portion 122, thereby preventing the anvil shaft portion 113 from coming off forward from the hammer case 6.

[0181] In the embodiment, the anvil bearing 115 is a sliding bearing.

[0182] In the above configuration, the second groove portion 122 is appropriately formed on the inner peripheral surface of the anvil bearing 115 which is a sliding bearing.

[0183] [Other Embodiments] In the above-described embodiment, the restraining member 123 is an O-ring made of rubber. The restraining member 123 does not have to be an O-ring, and may be a ring-shaped member made of synthetic resin or metal. Further, the restraining member 123 does not have to be ring-shaped, and may be, for example, a snap ring.

[0184] In the above-described embodiment, in the plane orthogonal to the output rotation shaft BX, the outer shape of the anvil shaft portion 113 in the first groove portion 121 is circular, and the outer shape of the anvil shaft portion 113 in the third groove portion 135 is circular. Also, the diameter Db of the anvil shaft portion 113 in the third groove portion 135 is made smaller than the diameter Da of the anvil shaft portion 113 in the first groove portion 121. The outer shape of the anvil shaft portion 113 at the break starting portion 134 does not have to be circular. It is sufficient that the section modulus of the break starting portion 134 is smaller than the section modulus of the anvil shaft portion 113 in the first groove portion 121.

[0185] In the above-described embodiment, the anvil bearing 115 is a sliding bearing. Further, the second groove portion 122 is formed on the inner peripheral surface of the sliding bearing. For example, the anvil bearing 115 may be constituted by two ball bearings arranged at intervals in the front-rear direction. The gap between the two ball bearings may function as the second groove portion 122.

[0186] In the above-described embodiment, the vibration damping member 138 is rubber. The vibration damping member 138 may include a spring. In the above-described embodiment, the vibration damping member 139 is a spring. The vibration damping member 139 may include rubber.

[0187] In the above-described embodiment, the vibration damping member 138 is arranged in the groove portion 141 provided in the main body housing 2, and the vibration damping member 139 is arranged in the recess 142 provided in the main body housing 2. Further, the convex portion 143 provided in the grip housing 3 is brought into contact with each of the vibration damping member 138 and the vibration damping member 139 supported by the main body housing 2. Each of the vibration damping member 138 and the vibration damping member 139 may be supported by the grip housing 3, and the convex portion provided in the main body housing 2 may be brought into contact with each of the vibration damping member 138 and the vibration damping member 139 supported by the grip housing 3.

[0188] In the above-described embodiment, the vibration damping mechanism 137 includes a vibration damping member 138 that suppresses transmission of vibration of the hammer case 6 in the axial direction parallel to the output rotation shaft BX to the grip housing 3, and a vibration damping member 139 that suppresses transmission of vibration of the hammer case 6 in the rotational direction centered on the output rotation shaft BX to the grip housing 3. The vibration damping mechanism 137 may have the vibration damping member 138 and may not have the vibration damping member 139. The vibration damping mechanism 137 may have the vibration damping member 139 and may not have the vibration damping member 138.

[0189] In the above-described embodiment, the impact tool 1 was assumed to be an impact wrench. The impact tool may be an impact driver. The anvil of the impact driver has an insertion hole into which the tip tool is inserted and a chuck mechanism for holding the tip tool.

[0190] In the above-described embodiment, the battery pack 63 attached to the battery attachment portion 9 was used as the power source of the impact tool 1. As the power source of the impact tool 1, a commercial power source (AC power source) may be used.

[0191] In the above-described embodiment, the motor 10 was assumed to be an inner rotor type brushless motor. The motor 10 may be an outer rotor type or a brushed motor.

Description of Reference Numerals

[0192] 1... Impact tool, 2... Main body housing, 2L... Left main body housing, 2R... Right main body housing, 3... Grip housing, 3L... Left grip housing, 3R... Right grip housing, 4... Motor housing, 5... Gear case, 6... Hammer case, 7... Side handle, 8... Bumper, 9... Battery mounting part, 10... Motor, 11... Controller, 12... Fan, 13... Reduction mechanism, 14... Spindle, 15... Impact mechanism, 16... Anvil, 17... Trigger switch, 18... Light assembly, 19... Screw, 20... Main body part, 21... Protrusion, 22... Gear case housing part, 23... Motor housing connection part, 24... Cylindrical part, 25... Rear wall part, 26... Screw, 27... Grip part, 28... Controller housing part, 29... Battery connection part, 30... Connecting part, 31... Rear grip part, 32... Upper grip part, 33... Front grip part, 34... Cylindrical part, 35... Lower wall part, 36... Opening, 37... Opening, 38... Opening, 39... Opening, 40A... Opening, 40B... Opening, 41... Opening, 42... Opening, 43... Opening, 44... Bearing cover, 45... Screw, 46... First cylindrical part, 47... Second cylindrical part, 48... Opening, 49... Opening, 50... Screw, 51... Screw boss, 52... Screw boss, 53... Screw, 54... Screw boss, 55... Handle part, 56... Base part, 57... First base part, 58... Second base part, 59... Hinge, 60... Tightening mechanism, 61... Screw, 62... Dial part, 63... Battery pack, 64... Terminal, 65... Terminal holder, 66... Spring, 67... Buffer member, 68... Stator, 69... Rotor, 70... Rotor shaft, 71... Stator core, 72... Insulator, 73... Coil, 74... Busbar unit, 75... Rotor core, 76... Rotor magnet, 77... Sensor board, 78... Rotor bearing, 79... Rotor bearing, 80... First bevel gear, 81... Controller case, 82... Air inlet, 83... Exhaust port, 84... Air inlet, 85... Baffle plate, 86... Second bevel gear, 87... Planetary gear mechanism, 88... Sun gear, 89... Planetary gear, 90... Internal gear, 91... Gear bearing, 92... Gear bearing, 93... Pin, 94... Flange part, 95... Spindle shaft part, 96... Protrusion, 97... Spindle bearing, 98... Hammer, 99... Ball, 100... First coil spring, 101... Second coil spring, 102... Third coil spring, 103... First washer, 104... Second washer, 105... Hammer body, 106... Hammer protrusion, 107... Recess108 … hole, 109 … ball, 110 … spindle groove, 111 … hammer groove, 112 … anvil recess, 113 … anvil shaft portion, 114 … anvil protrusion, 115 … anvil bearing, 116 … trigger lever, 117 … switch body, 118 … circuit board, 119 … light emitting element, 120 … light cover, 121 … first groove portion, 122 … second groove portion, 123 … restraining member, 124 … first portion, 125 … second portion, 126 … first front side surface, 127 … first rear side surface, 128 … first circumferential surface, 129 … second front side surface, 130 … second rear side surface, 131 … second circumferential surface, 132 … bearing support surface, 133 … seal member, 134 … breakage starting point portion, 135 … third groove portion, 136 … large diameter portion, 137 … vibration prevention mechanism, 138 … vibration prevention member (first vibration prevention member), 138A … vibration prevention member, 138B … vibration prevention member, 138C … vibration prevention member, 138D … vibration prevention member, 139 … vibration prevention member (second vibration prevention member), 139A … vibration prevention member, 139B … vibration prevention member, 140 … outer circumferential surface, 141 … groove portion, 141A … groove portion, 141B … groove portion, 141C … groove portion, 141D … groove portion, 142 … recess, 142A … recess, 142B … recess, 143 … protrusion, 143A … protrusion, 143B … protrusion, 143C … protrusion, 143D … protrusion, 144 … first support surface, 145 … second support surface, 146 … circumferential surface, 147 … first vibration prevention portion, 148 … second vibration prevention portion, 149 … third vibration prevention portion, 151 … partition wall, 152 … partition wall, 153 … partition wall, 154 … partition wall, 155 … partition wall, 156 … partition wall, 163 … notch, 164 … notch, 165 … notch, 166 … notch, 181 … ring spring, 190 … screw, 460 … cover, BX … output rotating shaft, CX … virtual axis, MX … motor rotating shaft, Da … diameter, Db … diameter.,

Claims

1. A motor, A striking mechanism rotatable about an output rotation shaft extending in the front-rear direction and driven by the motor, An anvil shaft portion disposed forward of the striking mechanism, and an anvil protrusion that protrudes radially outward from the rear end portion of the anvil shaft portion and is struck in the rotational direction about the output rotation shaft by the striking mechanism, an anvil having the same, A hammer case that houses the striking mechanism, An anvil bearing held by the hammer case and disposed around the anvil shaft portion, A first groove portion formed on the outer peripheral surface of the anvil shaft portion so as to surround the output rotation shaft, A large-diameter portion provided on the outer peripheral surface of the anvil shaft portion behind the first groove portion, A second groove portion formed on the inner peripheral surface of the anvil bearing so as to surround the output rotation shaft, A suppression member including a first portion disposed in the first groove portion and a second portion disposed in the second groove portion, In the front-rear direction, the second groove portion overlaps the first groove portion and the large-diameter portion, An impact tool.

2. The suppression member is ring-shaped and surrounds the output rotation shaft, The impact tool according to claim 1.

3. The suppression member is an O-ring that contacts each of the inner surface of the first groove portion and the inner surface of the second groove portion, The impact tool according to claim 1 or claim 2.

4. A motor, A striking mechanism rotatable about an output rotation shaft extending in the front-rear direction and driven by the motor, An anvil shaft portion disposed forward of the striking mechanism, and an anvil protrusion that protrudes radially outward from the rear end portion of the anvil shaft portion and is struck in the rotational direction about the output rotation shaft by the striking mechanism, an anvil having the same, A hammer case that houses the striking mechanism, An anvil bearing held by the hammer case and disposed around the anvil shaft portion, A first groove portion formed on the outer peripheral surface of the anvil shaft portion so as to surround the output rotation shaft, A second groove portion formed on the inner peripheral surface of the anvil bearing so as to surround the output rotation shaft, A suppression member including a first portion disposed in the first groove portion and a second portion disposed in the second groove portion, The anvil shaft portion has a breakage starting portion disposed behind the first groove portion and having a sectional modulus smaller than the sectional modulus of the anvil shaft portion in the first groove portion, An impact tool.

5. A third groove portion is formed on an outer peripheral surface of the anvil shaft portion so as to surround the output rotation shaft behind the first groove portion. A diameter of the anvil shaft portion in the third groove portion is smaller than a diameter of the anvil shaft portion in the first groove portion. The breakage starting portion includes the anvil shaft portion in the third groove portion. The impact tool according to claim 4.

6. The inner surface of the first groove portion includes a first front surface facing rearward, a first rear surface disposed rearward of the first front surface and facing forward, and a first circumferential surface connected to each of an end portion on a radially inner side of the first front surface and an end portion on a radially inner side of the first rear surface and facing outward in the radial direction. The inner surface of the second groove portion includes a second front surface facing rearward and a second circumferential surface connected to an end portion on a radially outer side of the second front surface and facing inward in the radial direction. The impact tool according to claim 4 or claim 5.

7. In a state where the anvil shaft portion is broken at the breakage starting portion, the suppression member contacts each of the first rear surface and the second front surface. The impact tool according to claim 6.

8. The hammer case has a bearing support surface that contacts a front end portion of the anvil bearing. The impact tool according to any one of claims 1 to 7.

9. The anvil bearing is a sliding bearing. The impact tool according to any one of claims 1 to 8.

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