JP2015009310A - Impact tool - Google Patents

Abstract

An impact tool capable of increasing the impact force of a hammer is provided. An impact tool comprising: a spindle 23; and a hammer 24 that is attached to the outer peripheral surface of the spindle 23 and converts a rotational force of the spindle 23 into an impact force in a rotational direction. And a plurality of first cam grooves 23b, 23c arranged in a circumferential direction centering on the axis A1 of the spindle 23 and the inner peripheral surface of the hammer 24, and centered on the axis A1. A plurality of second cam grooves 24a and 24b arranged in the circumferential direction, one of the plurality of first cam grooves 23b and 23c, and one of the plurality of second cam grooves 24a and 24b. As a set, a plurality of balls 25 held one by one in a plurality of sets of cam grooves, and the plurality of first cam grooves 23b and 23c are arranged at different positions in the direction along the axis A1. . [Selection] Figure 1

Description

  The present invention relates to a striking tool that converts a rotational force of a rotating member into a striking force in a rotating direction.

  2. Description of the Related Art Conventionally, a striking tool that converts a rotational force of a power source into a striking force in a rotating direction is known, and an example thereof is described in Patent Document 1. The impact tool described in Patent Document 1 includes an electric motor as a power source, a spindle to which the rotational force of the electric motor is transmitted via a speed reducer, and two first provided on the outer peripheral surface of the spindle. A cam groove, a hammer attached to the outer periphery of the spindle so as to be movable in the axial direction, two second cam grooves provided on the inner peripheral surface of the hammer, two first cam grooves and two second cam grooves And a claw provided on the hammer, and an anvil arranged coaxially with the spindle and rotatably.

  A driver bit as a tip tool is supported by the anvil. The two first cam grooves are V-shaped provided along the circumferential direction of the spindle and displaced in the axial direction. Further, when the outer peripheral surface of the spindle is developed on a plane, the two first cam grooves are bent in two stages.

  When the rotational force of the electric motor is transmitted to the driver bit through the spindle, ball, hammer, and anvil and a load is applied to the anvil when the object is tightened, the ball is in the first cam groove and the second cam groove. Roll along. Further, after the hammer moves in the axial direction against the force of the spring and away from the anvil, the hammer moves toward the anvil with the force of the spring, and the ball is in the first cam groove and the second cam groove. And the hammer applies a striking force in the rotational direction to the tip tool.

JP 2003-181774 A

  However, in the impact tool described in Patent Document 1 described above, since the two first cam grooves are bent in two stages, the resistance when the ball rolls through the two first cam grooves is increased, There was a problem that the striking force in the rotating direction generated by the hammer was insufficient.

  The objective of this invention is providing the impact tool which can raise the impact force of the rotation direction which generate | occur | produces with a hammer.

  The striking tool of one embodiment is a striking tool having a rotating member and a hammer that is attached to an outer peripheral surface of the rotating member and converts a rotating force of the rotating member into a striking force in a rotating direction, A plurality of first cam grooves provided on the outer peripheral surface of the rotating member and arranged in a circumferential direction around the axis of the rotating member; provided on the inner peripheral surface of the hammer; and the axis A plurality of second cam grooves arranged in a circumferential direction centered on the center, any one of the plurality of first cam grooves, and any one of the plurality of second cam grooves, A plurality of rolling elements held one by one in the set of cam grooves, and the plurality of first cam grooves are arranged at different positions in the direction along the axis.

  The striking tool according to another embodiment includes a rotating member, a hammer movable in a direction along the axis of the rotating member, a first cam groove provided on an outer peripheral surface of the rotating member, and an inner periphery of the hammer. A striking tool having a second cam groove provided on a surface, and a rolling element accommodated in the first cam groove and the second cam groove, wherein the first cam groove extends along the axis. A plurality are arranged at different positions in the direction.

  In another embodiment, the impact tool includes a rotating member, a hammer movable in a direction along an axis of the rotating member, a plurality of first cam grooves provided on an outer peripheral surface of the rotating member, An impact tool having a plurality of second cam grooves provided on an inner peripheral surface, and a plurality of rolling elements housed in the plurality of first cam grooves and the plurality of second cam grooves, The first cam groove has a first outermost portion of one of the first cam grooves in the circumferential direction of the rotating member and a second outermost portion of the other of the first cam grooves in the circumferential direction. , Are arranged at overlapping positions.

  According to the striking tool of one embodiment, the length of the plurality of first cam grooves can be increased as much as possible in the circumferential direction around the axis, and the striking force in the rotational direction generated by the hammer can be increased. .

It is side surface sectional drawing which shows the impact tool of this invention. It is an enlarged view which shows the spindle and hammer which were provided in the impact tool of FIG. It is a perspective view of the hammer provided in the striking tool of FIG. (A) is a development view of the outer peripheral surface of the spindle of FIG. 2, and (B) is a development view of the outer peripheral surface of the spindle and the outer peripheral surface of the hammer of FIG.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. The impact tool 10 shown in FIG. 1 is an impact driver. The striking tool 10 includes a battery pack 11 that houses battery cells that can be charged and discharged, and an electric motor 12 that is driven by power supplied from the battery pack 11. The electric motor 12 is a power source that converts electrical energy into kinetic energy. The impact tool 10 has a casing 13, and the electric motor 12 is disposed inside the casing 13.

  The electric motor 12 has a rotating shaft 14, and the rotating shaft 14 rotates about the axis A1. The electric motor 12 can switch the rotation direction of the rotating shaft 14 between forward and reverse. The striking tool 10 has an anvil 16 as a support member for supporting the tip tool 15, and the anvil 16 is rotatably supported by a sleeve 17 attached to the casing 13. The anvil 16 is rotatable about the axis A1, and the tip tool 15 is attached and detached.

  On the other hand, a speed reducer 18 is provided inside the casing 13. The speed reducer 18 is disposed between the electric motor 12 and the anvil 16 in a direction along the axis A1. The speed reducer 18 is a power transmission device that transmits the torque of the electric motor 12 to the anvil 16, and the speed reducer 18 is configured by a single pinion type planetary gear mechanism. The reduction gear 18 rotates a sun gear 19 disposed coaxially with the rotary shaft 14, a ring gear 20 provided so as to surround the outer periphery of the sun gear 19, and a plurality of pinion gears 21 meshed with the sun gear 19 and the ring gear 20, and And a carrier 22 supported so as to be revolved. The ring gear 20 is fixed to the casing 13 and cannot rotate.

  A spindle 23 that rotates together with the carrier 22 around the axis A1 is provided. That is, the rotating shaft 14, the speed reducer 18, the spindle 23, and the anvil 16 of the electric motor 12 are provided around the axis A1. The spindle 23 is disposed between the anvil 16 and the speed reducer 18 in a direction along the axis A1, and an end portion of the spindle 23 on the anvil 16 side protrudes in a direction along the axis A1. 23a is formed. A cylindrical holder 28 is attached to the inside of the casing 13, and a longitudinal end portion of the spindle 23 is rotatably supported by the holder 28 via a bearing 29. Further, two first cam grooves 23 b and 23 c are provided on the outer peripheral surface of the spindle 23. That is, a plurality of first cam grooves 23b and 23c are arranged.

  On the other hand, the end of the anvil 16 on the spindle 23 side is provided with a holding hole 16a coaxial with the axis A1, and the shaft 23a is rotatably inserted into the holding hole 16a. That is, the anvil 16 and the spindle 23 can be relatively rotated about the axis A1. Further, the anvil 16 is provided with a mounting hole 16c coaxially with the axis A1. The attachment hole 16c is opened in a portion of the anvil 16 exposed to the outside of the casing 13, and the attachment hole 16c is provided for attaching and detaching the tip tool 15.

  An annular hammer 24 is attached to the outer periphery of the spindle 23. The hammer 24 is disposed between the speed reducer 18 and the anvil 16 in a direction along the axis A1. The hammer 24 can rotate relative to the spindle 23 and can move relative to the spindle 23 in a direction along the axis A1. On the inner peripheral surface of the hammer 24, two second cam grooves 24a and 24b extending in the direction along the axis A1 are formed.

  Then, one ball 25 is held with the first cam groove 23b and the second cam groove 24a as a set, and one ball 25 is held with the first cam groove 23c and the second cam groove 24b as a set. Has been. That is, one ball 25 is held by each of the plurality of sets of cam grooves. The ball 25 is a metal rolling element. For this reason, the hammer 24 is movable in the direction along the axis A <b> 1 within a range in which the ball 25 can roll with respect to the spindle 23. Further, the hammer 24 is movable in the circumferential direction about the axis A <b> 1 within a range in which the ball 25 can roll with respect to the spindle 23.

  Further, an annular plate 30 is attached between the first cam grooves 23 b and 23 c and the carrier 22 in the direction along the axis A <b> 1 on the outer periphery of the spindle 23. A compression spring 26 is provided in a compressed state between the hammer 24 and the plate 27 in a direction along the axis A1. Since the carrier 22 is in contact with the bearing 29 and the holder 28, the movement in the direction along the axis A <b> 1 is restricted, and the pressing force of the compression spring 26 is applied to the hammer 24. The hammer 24 is pushed toward the anvil 16 in the direction along the axis A <b> 1 by the pressing force of the compression spring 26. An annular stopper 31 is provided on the outer periphery of the spindle 23 and inside the plate 30. The stopper 31 is integrally formed of a rubber-like elastic body, and the stopper 31 restricts the range in which the hammer 24 moves in the direction along the axis A1.

  A protrusion 16b protruding in the radial direction is provided at the end of the anvil 16 on the hammer 24 side. Two protrusions 16 b are provided at intervals of 180 degrees in the circumferential direction of the anvil 16. On the other hand, a protrusion 35 protruding in the direction along the axis A1 is provided at the end of the hammer 24 on the anvil 16 side. Two protrusions 35 are provided at an interval of 180 degrees in the circumferential direction of the hammer 24. The protrusion 16b and the protrusion 35 are arranged on the same circumference centering on the axis A1, and the protrusion 16b and the protrusion 35 can be engaged and released.

  Next, the characteristic structure of the impact tool 10, that is, the shape and structure of the first cam grooves 23b and 23c will be described with reference to FIG. The first cam grooves 23b and 23c are both V-shaped as shown in FIG. The first cam grooves 23 b and 23 c protrude in a direction approaching the anvil 16. Since the planar shapes of the two first cam grooves 23b and 23c are the same, the first cam groove 23b will be described below.

  The first cam groove 23b is formed by connecting two straight portions 32 and 33, and the straight portions 32 and 33 are extended in the circumferential direction of the spindle 23 and inclined in the direction along the axis A1. ing. A striking angle α1 on the acute angle side is set between the center line B1 in the width direction of one straight line portion 32 and the straight line C1. A striking angle α2 on the acute angle side is set between the center line B2 in the width direction of the other straight line portion 33 and the straight line C1. The straight line C1 passes through the intersection D1 between the center line B1 and the center line B2, and is perpendicular to the axis A1. Further, the hitting angle α1 and the hitting angle α2 are the same, and the hitting angles α1 and α2 are set to be the same within a range of 30 degrees to 35 degrees, for example.

  Further, the center line A <b> 2 passes through a connecting portion between the straight portion 32 and the straight portion 33. The straight portions 32 and 33 have the same width. The length in the direction along the center lines B1 and B2 is also the same. Furthermore, the center lines B1 and B2 intersect at the intersection D1 between the center line A2 and the straight line C1. As described above, in the plan view in which the outer peripheral surface of the spindle 23 is developed, the straight portions 32 and 33 are line symmetric with respect to the center line A2.

  Further, the first cam groove 23 b has one end 40 that occupies a predetermined position in the circumferential direction of the spindle 23, and the other end 41 that is disposed at a position different from the one end 40 in the circumferential direction of the spindle 23. . The one end 40 and the other end 41 are both ends of the first cam groove 23 b in the circumferential direction of the spindle 23. Further, the first cam groove 23 b has a top portion 42 disposed between the one end portion 40 and the other end portion 41 in the circumferential direction of the spindle 23. The top portion 42 is a portion where the first cam groove 23b protrudes most in the direction along the axis A1. Since the first cam groove 23b is V-shaped, the top portion 42 is disposed at a position different from the one end portion 40 and the other end portion 41 in the direction along the axis A1 of the spindle 23.

  On the other hand, in the plan view in which the outer peripheral surface of the spindle 23 is developed, the first cam groove 23c has the same shape and the same structure as the first cam groove 23b. Further, the first cam groove 23 c has one end 43 occupying a predetermined position in the circumferential direction of the spindle 23 and the other end 44 disposed at a position different from the one end 43 in the circumferential direction of the spindle 23. . The one end portion 43 and the other end portion 44 are both ends of the first cam groove 23 c in the circumferential direction of the spindle 23. The first cam groove 23 c has a top 45 disposed between the one end 43 and the other end 44 in the circumferential direction of the spindle 23. The top portion 45 is a portion where the first cam groove 23c protrudes most in the direction along the axis A1. Since the first cam groove 23 c is V-shaped, the top 45 is arranged at a position different from the one end 43 and the other end 44 in the direction along the axis A <b> 1 of the spindle 23.

  The first cam grooves 23b and 23c are provided on the outer peripheral surface of the spindle 23 at different positions in the direction along the axis A1. Specifically, the intersection D1 in the first cam groove 23b and the intersection D1 in the first cam groove 23c are arranged at different positions in the direction along the center line A2. The center line A2 is parallel to the axis A1. FIG. 4A shows an example in which the intersection point D1 in the first cam groove 23c is provided at a position closer to the anvil 16 than the intersection point D1 in the first cam groove 23b.

  Further, as shown in FIG. 4B, the first cam grooves 23b and 23c have the same length H1 in the direction along the center line A2. For this reason, the first cam grooves 23b and 23c have different arrangement ranges of the first cam grooves 23b and first cam grooves 23c in the direction along the center line A2. More specifically, in the direction along the center line A2, the arrangement range of the first cam groove 23b and the arrangement range of the first cam groove 23c partially overlap and differ in part. Furthermore, the top portion 42 of the first cam groove 23b and the top portion 45 of the first cam groove 23c are arranged at different positions in the direction along the axis A1. Furthermore, the top portion 42 of the first cam groove 23 b and the top portion 45 of the first cam groove 23 c are arranged at positions that are 180 degrees different in the circumferential direction of the spindle 23.

  In the state where the hammer 24 is in contact with the anvil 16 and stopped, the arrangement range of the first cam groove 23b and the arrangement range of the first cam groove 23c in the direction along the axis A1 are the arrangement range of the hammer 24. It is within.

  Furthermore, in the circumferential direction of the spindle 23, the arrangement range of the two first cam grooves 23b and 23c is a range exceeding 360 degrees. The first cam grooves 23b and 23c are arranged at different positions in the direction along the axis A1. For this reason, the end portion of the straight portion 32 of the first cam groove 23b and the end portion of the straight portion 33 of the first cam groove 23c are disposed so as to overlap in the range E1 in the circumferential direction of the spindle 23. Further, the end portion of the straight portion 33 of the first cam groove 23b and the end portion of the straight portion 32 of the first cam groove 23c are arranged so as to overlap in a range in the circumferential direction of the spindle 23. The size of the range E1 where the straight line portion 32 and the straight line portion 33 overlap is determined by the length of the straight line portion 32 in the direction of the center line B1 and the length of the straight line portion 33 in the direction of the center line B2.

  Here, the end portion of the straight portion 32 of the first cam groove 23b and the end portion of the straight portion 33 of the first cam groove 23c are the end portions in the circumferential direction of the spindle 23, and one end portion 40 and the like to be described later. It corresponds to the end 44. Further, the end portion of the straight portion 33 of the first cam groove 23b and the end portion of the straight portion 32 of the first cam groove 23c are end portions in the circumferential direction of the spindle 23, and one end portion 41 and the other end to be described later. This corresponds to the unit 43.

  Together with the fact that the first cam grooves 23b and 23c are provided at different positions in the direction along the axis A1, the second cam grooves 24a and 24b extend along the center line A3 as shown in FIG. It is provided at different positions in different directions. The center line A3 is parallel to the center line A2 and the axis A1, and FIG. 4B shows a state in which the center line A2 and the center line A3 are in the same place for convenience. The second cam grooves 24 a and 24 b are substantially pentagonal in FIG. 4B, which is a plan view in which the inner peripheral surface of the hammer 24 is developed, and the second cam grooves 24 a and 24 b are circumferential directions of the hammer 24. Are provided at different positions.

  The second cam groove 24a is provided in a predetermined range in the circumferential direction centered on the center line A3, and the second cam groove 24b is provided in a predetermined range in the circumferential direction centered on the center line A3. The center line A3 of the second cam groove 24a and the center line A3 of the second cam groove 24b are parallel, and the center line A3 is parallel to the axis A1. The center line A3 of the second cam groove 24a and the center line A3 of the second cam groove 24b are arranged 180 degrees apart in the circumferential direction of the hammer 24. The distal end portion 38 of the second cam groove 24a is disposed at a position farther from the anvil 16 than the distal end portion 38 of the second cam groove 24b in the direction along the center line A3.

  4A is a plan view showing the spindle 23 unfolded, and FIG. 4B is a plan view showing the spindle 23 and the hammer 24 unfolded. The direction along is synonymous with the direction along axis A1 in FIG.

  Next, the operation of the impact tool 10 will be described. When the electric motor 12 is stopped, the hammer 24 pressed by the compression spring 26 is in contact with the anvil 16 and stopped. When electric power is supplied to the electric motor 12 and the rotating shaft 14 rotates, the torque of the rotating shaft 14 is transmitted to the sun gear 19 of the speed reducer 18. When torque is transmitted to the sun gear 19, the ring gear 20 becomes a reaction force element, and the carrier 22 becomes an output element. That is, when the torque of the sun gear 19 is transmitted to the carrier 22, the torque is amplified by the rotation speed of the carrier 22 being lower than the rotation speed of the sun gear 19.

  When torque is transmitted to the carrier 22, the spindle 23 rotates together with the carrier 22. The torque of the spindle 23 is transmitted to the hammer 24 via the ball 25. The torque of the hammer 24 is transmitted to the anvil 16 by the engaging force between the protrusion 35 and the protrusion 16b, and the anvil 16 rotates. The rotational force of the anvil 16 is transmitted to the bolt through the tip tool 15, and the bolt is screwed into an object, for example, wood.

  In a state where the torque required to rotate the tip tool 15 is low, that is, in a low load state, the center of the ball 25 is positioned on the center line A3 as shown in FIG. The center line A3 is in an overlapping state.

  Thereafter, when the bolt is screwed into the wood and the frictional resistance between the wood and the bolt increases and the rotational force necessary to rotate the tip tool 15 increases, the anvil 16 stops and the ball 25 and the second cam The ball 25 rolls in the first cam grooves 23 b and 23 c and the second cam grooves 24 a and 24 b due to the reaction force generated on the contact surface with the grooves 24 a and 24 b, and the hammer 24 moves in a direction away from the anvil 16.

  Here, the hammer 24 moves along the axis A <b> 1 against the pressing force of the compression spring 26. Then, the protrusion 35 and the protrusion 16b are released, and the rotational force of the hammer 24 is not transmitted to the anvil 16. Further, the end of the hammer 24 in the reciprocating direction collides with the stopper 31, and the stopper 31 absorbs kinetic energy when the hammer 24 moves away from the anvil 16. The stopper 31 restricts the range in which the hammer 24 operates in the direction away from the anvil 16 along the axis A1.

  Further, when the rotation of the hammer 24 is continued and the protrusion 35 gets over the protrusion 16b, the pressing force applied to the hammer 24 by the compression spring 26 is higher than the force for moving the hammer 24 away from the anvil 16. Become. Then, the ball 25 rolls along the first cam grooves 23b and 23c and the second cam grooves 24a and 24b, so that the hammer 24 and the spindle 23 rotate relative to each other, and the hammer 24 approaches the anvil 16. Move with.

  Thereafter, the projecting portion 35 of the rotating hammer 24 collides with the projecting portion 16b of the stopped anvil 16, and a striking force in the rotational direction is applied to the anvil 16 and the tip tool 15. In addition, if the rotation direction of the rotating shaft 14 of the electric motor 12 is reversed, the bolt can be loosened.

  In the impact tool 10 according to the present embodiment, the first cam grooves 23b and 23c are arranged at different positions in the direction along the axis A1. The one end 40 of the first cam groove 23b and the other end 44 of the first cam groove 23c overlap in the range E1 in the circumferential direction of the spindle 23. Accordingly, the length L1 of the straight portions 32 and 33 of the first cam grooves 23b and 23c can be made as long as possible in the circumferential direction of the spindle 23, that is, the direction along the straight line C1. This length L1 affects the impact force.

  That is, when the hammer 24 strikes the anvil 16, the amount of movement of the hammer 24 in the circumferential direction of the spindle 23 can be made as long as possible. Therefore, the striking force transmitted from the hammer 24 to the tip tool 15 can be increased. Further, by increasing the length L1, it is possible to suppress the impact on the stopper 31 due to the reaction when the hammer 24 strikes the anvil 16. For this reason, damage to the internal mechanism of the casing 13 such as the stopper 31 can be suppressed, and the life of the stopper 31 can be extended.

  Thus, in order to make the length L1 of the straight portions 32 and 33 of the first cam grooves 23b and 23c as long as possible, if the impact angles α1 and α2 are set as small as possible, in the direction along the center line A2, Each length H1 of the first cam grooves 23b, 23c can be made as short as possible. Therefore, the spindle 23 can suppress an increase in the total length in the direction along the axis A1, contribute to downsizing the impact tool 10, and increase the impact force. The length H1 affects the axial force, that is, the force acting in the axial direction. The axial direction means a direction along the axis A1. By shortening the length H1, the moving speed when the hammer 24 collides with the stopper 31 can be reduced. Furthermore, if the striking angles α1, α2 are set as small as possible, the axial force transmitted from the hammer 24 to the anvil 16 can be reduced, and the noise of the striking tool 10 can be reduced.

  Further, in the hammer 24, the distal end portion 38 of the second cam groove 24a and the distal end portion 38 of the second cam groove 24b are provided at different positions in the direction along the center line A3. That is, in FIG. 4B where the inner peripheral surface of the hammer 24 is developed, the area of the second cam groove 24a is larger than the area of the second cam groove 24b. Therefore, means for adjusting the balance of the hammer 24 is provided in order to prevent the hammer 24 from being dynamically unbalanced in the radial direction about the axis A1.

  Specifically, as shown in FIG. 3, a balance portion 39 is provided in which a part of the outer peripheral surface of the hammer 24 protrudes outward in the radial direction of a circle centered on the axis A1. The balance portion 39 is provided in a region where the second cam groove 24 a is provided in the circumferential direction of the hammer 24. In this way, the center of gravity of the hammer 24 is set on the axis A1. Therefore, when the hammer 24 rotates about the axis A1, the dynamic balance of the hammer 24 is maintained in the radial direction about the axis A1, and the hammer 24 and the spindle 23 vibrate radially about the axis A1. Can be suppressed.

  The spindle 23 described in the present embodiment corresponds to the rotating member of the present invention, the electric motor 12 corresponds to the power source of the present invention, and the one end portions 40 and 43 correspond to the first endmost portion of the present invention. The other end portions 41 and 44 correspond to the second endmost portion of the present invention.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the impact tool of the present invention includes an impact driver, a driver drill, and an impact wrench. Moreover, the impact tool of this invention contains the structure which can supply the electric power of alternating current power supply to an electric motor not via a battery pack. Furthermore, the impact tool of the present invention includes a structure capable of switching the power of the battery pack and the power of the AC power source and supplying it to the electric motor.

  Furthermore, the power source of the present invention includes an engine, a pneumatic motor, a hydraulic motor and the like in addition to the electric motor. The engine is a power source that converts thermal energy generated by burning fuel into kinetic energy. Examples of the engine include a gasoline engine, a diesel engine, and a liquefied petroleum gas engine. The electric motor includes a motor with a brush, a motor without a brush, and the like. Furthermore, the impact tool of the present invention includes a structure in which the tip tool is directly attached to the anvil and a structure in which the tip tool is attached to the anvil via a socket or an adapter. Furthermore, the one end part and the other end part of the first cam groove are located at both ends in the circumferential direction of the rotating member, which may be the one end part and which may be the other end part.

  DESCRIPTION OF SYMBOLS 10 ... Impact tool, 12 ... Electric motor, 18 ... Reduction gear, 23 ... Spindle, 23b, 23c ... 1st cam groove, 24 ... Hammer, 24a, 24b ... 2nd cam groove, 25 ... Ball, 39 ... Balance part, 40, 43 ... one end, 41, 44 ... other end, 42, 45 ... top, A1 ... axis.

Claims (12)

A hammering tool comprising: a rotating member; and a hammer attached to an outer peripheral surface of the rotating member and converting a rotational force of the rotating member into a striking force in a rotational direction,
A plurality of first cam grooves provided on an outer peripheral surface of the rotating member and arranged in a circumferential direction around the axis of the rotating member;
A plurality of second cam grooves provided on an inner peripheral surface of the hammer and arranged in a circumferential direction around the axis;
A plurality of rolling elements held one by one in the plurality of sets of cam grooves, one set of any of the plurality of first cam grooves and one of the plurality of second cam grooves;
Have
The impact tool, wherein the plurality of first cam grooves are arranged at different positions in a direction along the axis.   2. The impact tool according to claim 1, wherein a part of the plurality of first cam grooves is arranged at the same position in a circumferential direction around the axis.   The impact tool according to claim 1, wherein the hammer has a balance portion that maintains a dynamic balance in a radial direction centered on the axis. A power source for transmitting a rotational force to the rotating member;
In transmitting the rotational force of the power source to the rotating member, a speed reducer that reduces the rotational speed of the rotating member relative to the rotational speed of the power source;
The striking tool according to any one of claims 1 to 3, wherein is provided.   The impact tool according to claim 4, wherein the power source includes an electric motor that generates electric power by converting electric energy into kinetic energy. A rotating member; a hammer movable in a direction along an axis of the rotating member; a first cam groove provided on an outer peripheral surface of the rotating member; and a second cam groove provided on an inner peripheral surface of the hammer. And an impact tool having rolling elements accommodated in the first cam groove and the second cam groove,
A plurality of the first cam grooves are arranged at different positions in the direction along the axis. The plurality of first cam grooves are
One end of the rotating member in the circumferential direction;
The other end disposed at a position different from the one end in the circumferential direction of the rotating member;
A top portion disposed between the one end portion and the other end portion in a circumferential direction of the rotating member;
Each with
The impact tool according to claim 6, wherein in each of the plurality of first cam grooves, the top portion is disposed at a position different from the one end portion and the other end portion in a direction along the axis.   The impact tool according to claim 7, wherein the one end portion of one of the first cam grooves overlaps the other end portion of the other first cam groove in the circumferential direction. The plurality of first cam grooves is two,
The impact tool according to claim 7 or 8, wherein the top portions of the two first cam grooves are arranged at positions different by 180 degrees in a circumferential direction of the rotating member. A rotating member; a hammer movable in a direction along an axis of the rotating member; a plurality of first cam grooves provided on an outer peripheral surface of the rotating member; and a plurality of provided on an inner peripheral surface of the hammer. An impact tool having a second cam groove and a plurality of rolling elements housed in the plurality of first cam grooves and the plurality of second cam grooves,
The plurality of first cam grooves include a first outermost portion of one of the first cam grooves in the circumferential direction of the rotating member and a second outermost portion of the other first cam groove in the circumferential direction. A striking tool that is arranged in an overlapping position.   The impact tool according to claim 10, wherein the plurality of first cam grooves are arranged at different positions in a direction along the axis. The plurality of first cam grooves each have a top portion located between the first endmost portion and the second endmost portion in the circumferential direction,
The impact tool according to claim 11, wherein the top portions of each of the plurality of first cam grooves are arranged at different positions in a direction along the axis.

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