WO2018142742A1

WO2018142742A1 - Rotary impact tool

Info

Publication number: WO2018142742A1
Application number: PCT/JP2017/043087
Authority: WO
Inventors: 隆司草川; 雅理村松
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2017-01-31
Filing date: 2017-11-30
Publication date: 2018-08-09
Also published as: JP2018122393A

Abstract

In a rotary impact tool 1, a sub-hammer support structure has a structure in which a plurality of steel balls 17 are disposed between a sub-hammer 21 and a carrier 16. The plurality of steel balls 17 are disposed between a first retention groove 21g of the sub-hammer 21 and a second retention groove 16a of the carrier 16 so as to receive the loads in a direction different from the rotational-axis direction and radial directions perpendicular to the rotational-axis direction. The first retention groove 21g and the second retention groove 16a are formed into an arc shape in cross section in the rotational-axis direction, and cross-sectional radii thereof are larger than the steel balls 17.

Description

Rotating hammer tool

The present invention relates to a rotary impact tool.

Patent Document 1 discloses an impact including a spindle rotated by a driving unit, an anvil disposed in front of the spindle in the rotation axis direction, and a rotary striking mechanism that converts the rotation of the spindle into a rotational striking and transmits it to the anvil. Disclose wrench. The rotary striking mechanism includes a main hammer that can rotate about the rotation axis of the spindle and move in the axial direction, and a secondary hammer that houses the main hammer and rotates integrally with the main hammer, but does not move in the axial direction. With. In the impact wrench disclosed in Patent Document 1, a cam structure in which a steel ball is arranged between a guide groove on the spindle side and an engagement groove on the main hammer side is provided, and the main hammer can move backward and forward at high speed. Repeat with to give the anvil a rotational impact.

In the impact wrench disclosed in Patent Document 1, a rolling bearing that receives a load in the radial direction with respect to the rotation axis of the spindle is disposed between the auxiliary hammer and the spindle, and the inner periphery of the rear end of the auxiliary hammer is the rolling bearing. Press-fitted into the outer ring. In this impact wrench, a radial load applied to the rolling bearing is reduced by forming a gap between the outer periphery of the spindle and the inner ring of the rolling bearing.

JP 2014-240108 A

In the impact wrench disclosed in Patent Document 1, in order to prevent the core and the secondary hammer from swinging, a large rolling bearing is used and the trailing end of the secondary hammer that is press-fitted into the outer ring of the rolling bearing is formed thick. There is a need. For this reason, the weight and size of the support structure of the secondary hammer tend to increase.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for reducing the size of a support structure of a secondary hammer in a rotary impact tool having a primary hammer and a secondary hammer.

In order to solve the above-described problems, a rotary impact tool according to an aspect of the present invention includes a drive unit, a spindle rotated by the drive unit, an anvil disposed in front of the spindle in the rotation axis direction, and a rotation axis of the spindle. A main hammer that is rotatable about the axis and movable in the direction of the rotation axis, a cam structure in which a first steel ball is disposed between a guide groove on the spindle side and an engagement groove on the main hammer side, and a main hammer. And a sub-hammer that can rotate integrally with the main hammer, and a large-diameter portion that is provided on the rear side of the guide groove and has a larger outer diameter than the portion of the spindle on which the guide groove is formed. The rotary impact tool of this aspect further includes a secondary hammer support structure in which a second steel ball is disposed between the secondary hammer and the large diameter portion. In the secondary hammer support structure, the second steel ball has a rotational axis direction and a rotational axis. It arrange | positions between a sub hammer and a large diameter part so that the load of a direction different from the radial direction orthogonal to a direction may be received.

It is a section schematic diagram of the principal part of the rotary impact tool concerning an embodiment. It is a disassembled perspective view of the component of the rotation impact mechanism which concerns on embodiment. It is an assembly perspective view of the rotation impact mechanism concerning an embodiment. (A) is a front side perspective view of a main hammer, (b) is a perspective view of a spindle and a carrier, and (c) is a rear side perspective view of a sub hammer. (A) And (b) is a figure which shows the operation state of a cam structure. (A)-(c) is a figure which shows the positional relationship which expanded the engagement surface of the main hammer and the anvil typically in the circumferential direction. It is a figure which shows the sub hammer support structure which concerns on embodiment. It is a figure which shows the load direction which a steel ball receives in a sub hammer support structure.

The rotary impact tool of the embodiment includes a drive unit, a spindle rotated by the drive unit, an anvil disposed in front of the spindle in the rotation axis direction, and rotation for converting the rotation of the spindle into rotary strike and transmitting the rotation to the anvil. A striking mechanism. The rotary hammering mechanism employs a double hammer configuration, and includes a main hammer that is rotatable about the rotation axis of the spindle and is movable in the axial direction, and a secondary hammer that accommodates the main hammer and can rotate together with the main hammer. The rotary striking mechanism has a function of causing the main hammer to impactably engage the anvil and rotating the anvil about the axis.

FIG. 1 is a schematic cross-sectional view of a main part of a rotary impact tool according to an embodiment. In FIG. 1, an alternate long and short dash line indicates a rotation axis of the rotary impact tool 1. FIG. 2 is an exploded perspective view of components of the rotary impact mechanism according to the embodiment, and FIG. 3 is an assembled perspective view of the rotary impact mechanism according to the embodiment. 4A is a front perspective view of the main hammer, FIG. 4B is a perspective view of the spindle and the carrier, and FIG. 4C is a rear perspective view of the auxiliary hammer. In FIG. 1 and FIG. 3, the illustration of a stop member 27 described later is omitted. Hereinafter, the structure of the rotary impact tool 1 will be described with reference to FIGS.

The rotary impact tool 1 includes a housing 2 that constitutes a tool body. The upper part of the housing 2 forms an accommodation space for accommodating various components, and the lower part of the housing 2 constitutes a grip portion 3 that is gripped by the user. An operation switch 4 that is operated by a user's finger is provided on the front side of the grip 3, and a battery (not shown) that supplies power to the drive unit 10 is provided at the lower end of the grip 3.

The drive unit 10 is an electric motor, and the drive shaft 10 a of the drive unit 10 is connected to the carrier 16 and the spindle 11 via the power transmission mechanism 12. The carrier 16 is located on the rear end side of the spindle 11 and accommodates a power transmission gear. With reference to FIG. 4B, the carrier 16 is configured as a large-diameter portion having an outer diameter larger than that of the spindle 11. The carrier 16 has a front member 16b having a diameter larger than that of the spindle 11, and a rear member 16c positioned rearward of the front member 16b, and accommodates a gear between the front member 16b and the rear member 16c. The space 16d is formed.

The power transmission mechanism 12 includes a sun gear 13 that is press-fitted and fixed to the tip of the drive shaft 10 a, two planetary gears 14 that mesh with the sun gear 13, and an internal gear 15 that meshes with the planetary gear 14. The planetary gear 14 is rotatably supported in a space 16d of the carrier 16 by a support shaft 14a fixed to the front member 16b and the rear member 16c. The internal gear 15 is fixed to the inner peripheral surface of the housing 2.

With the power transmission mechanism 12 configured as described above, the rotation of the drive shaft 10a is decelerated based on the ratio between the number of teeth of the sun gear 13 and the number of teeth of the internal gear 15, and the rotational torque is increased. . As a result, the carrier 16 and the spindle 11 can be driven at low speed and high torque.

Rotating impact mechanism of the rotating impact tool 1 includes a spindle 11, a carrier 16, a main hammer 20, a secondary hammer 21 and a spring member 23. The spindle 11 is formed in a columnar shape, and a small-diameter protrusion 11 a is formed at the tip thereof coaxially with the axis of the spindle 11. The protrusion 11a is inserted in a rotatable state into a hole having a cylindrical inner space formed in the rear part of the anvil 22.

A steel main hammer 20 having a substantially disc shape and having a through hole in the center is mounted on the outer periphery of the spindle 11. A pair of hammer claws 20 a projecting toward the anvil 22 are formed on the front surface of the main hammer 20. The main hammer 20 is attached to the spindle 11 so as to be rotatable about the rotation axis of the spindle 11 and to be movable in the direction of the rotation axis of the spindle 11, that is, in the front-rear direction. As a result, the main hammer 20 can apply a rotational striking force to the anvil 22. The auxiliary hammer 21 is formed as a steel cylindrical member, and is divided into a front part 21a and a rear part 21b by an annular partition part 21e. The sub hammer 21 accommodates the main hammer 20 in the internal space of the front portion 21a.

The auxiliary hammer 21 and the main hammer 20 are provided with an integral rotation mechanism that rotates together. Referring to FIG. 2, the main hammer 20 includes four first pin grooves 20 d on its outer peripheral surface and having a semicircular cross section and parallel to the rotation axis of the spindle 11. The auxiliary hammer 21 includes four second pin grooves 21 c on the inner peripheral surface of the front portion 21 a and having a semicircular cross section and parallel to the rotation axis of the spindle 11. Here, the four second pin grooves 21 c of the sub hammer 21 are formed at positions corresponding to the four first pin grooves 20 d of the main hammer 20. The first pin grooves 20 d may be formed at an interval of 90 degrees on the outer peripheral surface of the main hammer 20. At this time, the second pin grooves 21 c are formed at an interval of 90 degrees on the inner peripheral surface of the sub hammer 21.

In the second pin groove 21c, an engagement pin 26 that is a cylindrical member is disposed. The engagement pin 26 may be a needle roller. The engagement pin 26 is inserted into the second pin groove 21c from the front end side of the sub hammer 21 and is inserted to the groove bottom portion provided in the step portion 21f protruding to the inner periphery. With the engagement pin 26 inserted to the bottom of the groove, a stop member 27 having a function of preventing the engagement pin 26 from being detached is fitted into the annular groove 21d formed on the inner peripheral surface of the sub hammer 21. By disposing the stop member 27 in the annular groove 21d, the movement of the engagement pin 26 in the second pin groove 21c is limited.

At the time of assembly, the four first pin grooves 20d of the main hammer 20 and the four engagement pins 26 are aligned with the four engagement pins 26 attached to the four second pin grooves 21c of the sub hammer 21. Then, the main hammer 20 is inserted into the sub hammer 21. As a result, the main hammer 20 and the sub hammer 21 can be rotated together around the rotation axis of the spindle 11.

The spring member 23 is interposed between the rear part of the main hammer 20 and the annular partition part 21e of the sub hammer 21. The main hammer 20 can move in the front-rear direction using the engaging pin 26 as a guide, and can apply a rotational striking force to the anvil 22 by the biasing force of the spring member 23.

The spindle 11 includes two guide grooves 11b on the outer peripheral surface thereof, and the main hammer 20 includes two engagement grooves 20b on the inner peripheral surface of the through hole. The two guide grooves 11b have the same shape and are arranged in the circumferential direction, and the two engagement grooves 20b have the same shape and are arranged in the circumferential direction. With the main hammer 20 mounted on the outer periphery of the spindle 11, a steel ball 19 is disposed between the guide groove 11b and the engagement groove 20b. The guide groove 11b on the spindle 11 side, the engagement groove 20b on the main hammer 20 side, and the steel ball 19 disposed between them constitute a “cam structure”. The two steel balls 19 support the main hammer 20 in the radial direction so that the main hammer 20 can rotate around the rotation axis of the spindle 11 and move in the direction of the rotation axis.

In the cam structure, the guide groove 11b is formed in a V shape or a U shape when viewed from the tool tip side. That is, the guide groove 11b has two inclined grooves that are symmetrically inclined in the rear oblique direction from the foremost part. The engagement groove 20b is formed in a V-shape or U-shape in the reverse direction when viewed from the tool front end side. When the steel ball 19 moves along the inclined groove from the frontmost part of the guide groove 11b, the main hammer 20 moves backward relative to the spindle 11.

The auxiliary hammer 21 includes an annular first holding groove 21g on the rear surface of the annular partition portion 21e, and the carrier 16 having a diameter larger than that of the spindle 11 includes an annular second holding groove 16a on the front outer periphery of the front member 16b. Between the first holding groove 21g and the second holding groove 16a, the plurality of steel balls 17 are arranged without gaps in the circumferential direction. The steel ball 17 may be formed smaller than the steel ball 19. The first holding groove 21g on the sub hammer 21 side, the second holding groove 16a on the carrier 16 side, and the steel ball 17 arranged without a gap therebetween constitute a “sub hammer support structure”. In the secondary hammer support structure, the steel ball 17 is disposed between the secondary hammer 21 and the carrier 16 so as to receive a load in a direction different from the rotational axis direction of the spindle 11 and the radial direction orthogonal to the rotational axis direction.

The stopper member 30 is provided between the main hammer 20 and the carrier 16, and restricts the range of movement of the main hammer 20 in the rotational axis direction so that the steel ball 19 in the cam structure does not collide with the end of the inclined groove. The stopper member 30 may be formed of a resin material, for example.

The anvil 22 that engages with the main hammer 20 is made of steel, and is rotatably supported by the housing 2 via a steel or brass sliding bearing. The tip of the anvil 22 is provided with a tool mounting portion 22a having a square cross section for mounting a socket body to be mounted on the head of a hexagon bolt or a hexagon nut.

A pair of anvil claws that engage with the pair of hammer claws 20a of the main hammer 20 are provided at the rear of the anvil 22. Each of the pair of anvil claws is formed as a columnar member having a sectional fan shape. The anvil claw of the anvil 22 and the hammer claw 20a of the main hammer 20 do not necessarily have to be two, and if the number of the respective claws is equal, three or more at equal intervals in the circumferential direction of the anvil 22 and the main hammer 20 It may be provided.

Next, the operation of the cam structure in the rotary impact tool 1 of the embodiment will be described.
When the drive unit 10 is rotationally driven by the pulling operation of the operation switch 4 by the user, the carrier 16 and the spindle 11 are rotated via the power transmission mechanism 12. The rotational force of the spindle 11 is transmitted to the main hammer 20 through a steel ball 19 fitted between the guide groove 11b of the spindle 11 and the engagement groove 20b of the main hammer 20, and the main hammer 20 and the sub hammer 21 are integrated. And rotate.

Fig. 5 (a) shows the state of the cam structure immediately after the start of tightening the bolts and nuts, and Fig. 5 (b) shows the state of the cam structure after a lapse of time from the start of tightening. FIG.5 (b) is a comparison figure for comparing with the initial state of the cam structure shown to Fig.5 (a), and shows a mode that the steel ball 19 moves toward the groove edge part from the foremost part of the guide groove 11b. ing.

6 (a) to 6 (c) show a positional relationship in which the engagement surfaces of the main hammer 20 and the anvil 22 are schematically developed in the circumferential direction. Here, FIG. 6A shows an engaged state between the hammer claw 20a of the main hammer 20 and the anvil claw 22b of the anvil 22 immediately after the start of tightening the bolts and nuts.

As shown in FIGS. 6A to 6C, a rotational force A due to the rotation of the driving unit 10 is applied to the main hammer 20 in the direction indicated by the arrow. Further, a forward biasing force B by the spring member 23 is applied to the main hammer 20 in the direction indicated by the arrow.

When the main hammer 20 rotates, the rotational force of the main hammer 20 is transmitted to the anvil 22 by the circumferential engagement of the hammer claws 20a and the anvil claws 22b. As the anvil 22 rotates, a socket body (not shown) attached to the tool mounting portion 22a rotates, and initial tightening is performed by applying a rotational force to the bolts and nuts. Since the spring member 23 applies the urging force B to the main hammer 20, the steel ball 19 is positioned at the foremost part of the guide groove 11b as shown in FIG. At this time, the hammer claw 20a and the anvil claw 22b are in an engaged state with the maximum engagement length.

When the load torque applied to the anvil 22 increases as the tightening of the bolts and nuts proceeds, a rotational force in the Y direction is generated in the main hammer 20. When the load torque exceeds a predetermined value, the steel ball 19 moves in the direction indicated by the arrow F along the inclined surfaces of the guide groove 11b and the engagement groove 20b against the biasing force B of the spring member 23, and the main hammer. 20 moves in the backward direction (X direction).

When the steel ball 19 moves in the inclined groove and the main hammer 20 moves in the X direction by a distance corresponding to the maximum engagement length between the hammer claw 20a and the anvil claw 22b, as shown in FIG. The engagement between the hammer claw 20a and the anvil claw 22b is released.

When the hammer claw 20a is detached from the anvil claw 22b, the biasing force B of the compressed spring member 23 is released, so that the main hammer 20 rotates at a high speed in the direction in which the rotational force A is applied. Move forward by force B.

Then, as shown in FIG. 6C, the hammer claw 20 a moves along the locus indicated by the arrow G, collides with the anvil claw 22 b, and applies a striking force in the rotation direction to the anvil 22. Thereafter, the hammer claw 20a is moved in the direction opposite to the locus G by the reaction, but finally returns to the state shown in FIG. 6A by the rotational force A and the urging force B. The above operation is repeated at a high speed, and the rotational hammering force by the main hammer 20 is repeatedly applied to the anvil 22.

The above is the description of the operation when tightening the bolt or nut, but when the tightened bolt or nut is loosened, the same operation as when tightening is performed by the rotary impact mechanism. In this case, by rotating the drive unit 10 in a direction opposite to that during tightening, the steel ball 19 moves to the upper right along the guide groove 11b shown in FIG. 5A, and the hammer claw 20a moves the anvil claw 22b. Strike in the direction opposite to the direction of tightening.

Since the rotary impact tool 1 of the embodiment employs a double hammer configuration, the magnitude of the impact in the rotational direction is proportional to the total moment of inertia of the main hammer 20 and the secondary hammer 21, while the magnitude of the impact in the rotational axis direction. The length is proportional to the mass of the main hammer 20. Compared with the rotary impact tool 1 using one hammer having the total mass of the main hammer 20 and the secondary hammer 21, the rotary impact tool 1 of the embodiment has the same impact magnitude in the rotational direction as it is in the rotational axis direction. Reduce the magnitude of impact. By making the mass of the main hammer 20 as small as possible compared with the mass of the sub hammer 21, the impact force generated in the direction of the rotation axis can be further reduced.

Furthermore, in the rotary impact tool 1 of the embodiment, the moment of inertia is increased by utilizing the fact that the magnitude of the moment of inertia is proportional to the square of the radius of rotation. That is, by providing the auxiliary hammer 21 having a large mass on the outer peripheral side of the main hammer 20, the moment of inertia of the auxiliary hammer 21 is increased and the impact force in the rotational direction by the double hammer is increased.

FIG. 7 is a view showing a sub hammer support structure according to the embodiment. FIG. 8 shows the direction of load received by the steel ball in the auxiliary hammer support structure. The auxiliary hammer support structure has a structure in which a plurality of steel balls 17 are arranged between the auxiliary hammer 21 and the carrier 16.

An annular first holding groove 21g for holding the steel ball 17 is provided on the rear surface of the annular partition portion 21e of the sub hammer 21. The cross section of the first holding groove 21g in the rotation axis direction is formed in an arc shape, and the cross-sectional radius of the first holding groove 21g is larger than the radius of the steel ball 17. An annular second holding groove 16 a for holding the steel ball 17 is provided on the outer periphery of the front surface of the front member 16 b of the carrier 16. The cross section of the second holding groove 16 a in the rotation axis direction is formed in an arc shape, and the cross sectional radius of the second holding groove 16 a is larger than the radius of the steel ball 17.

In this way, the first holding groove 21g and the second holding groove 16a are formed, and the steel ball 17 is sandwiched between the first holding groove 21g and the second holding groove 16a. 21g and the 2nd holding groove 16a are contacted stably and reliably. Thereby, the steel ball 17 can support the auxiliary hammer 21 suitably.

As shown in FIG. 8, the steel ball 17 is arranged between the first holding groove 21g and the second holding groove 16a so as to receive a load in a direction different from the rotation axis direction and the radial direction of the spindle 11. In the rotary impact tool 1, a load in the rotation axis direction and a load in the radial direction are generated by the impact of the rotary impact by the rotary impact mechanism. The auxiliary hammer support structure of the embodiment is different from the case where the plurality of steel balls 17 receive a load in a direction different from the rotation axis direction and the radial direction, for example, compared to the case where the auxiliary hammer 21 is supported by a rolling bearing. The support structure is downsized.

Here, if the load in the rotation axis direction acting on the steel ball 17 is compared with the magnitude of the load in the radial direction, since the spring load by the spring member 23 is applied in the rotation axis direction, the load in the rotation axis direction is the radial direction. Greater than load. Therefore, in order to disperse the resultant force of the load, it is preferable to set α to an angle smaller than 45 degrees, where α is an angle formed between the load direction received by the steel ball 17 and the radial direction. Thereby, the load in the rotation axis direction can be effectively dispersed, and the life of the steel ball 17 can be extended.

The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to each component or combination of each processing process, and such modifications are within the scope of the present invention. .

In the auxiliary hammer support structure of the embodiment, the steel ball 17 is disposed between the auxiliary hammer 21 and the carrier 16. However, in the modified example, the steel ball 17 is connected to the auxiliary hammer 21 and a member having an outer diameter larger than that of the spindle 11. The auxiliary hammer 21 may be supported by being disposed between the two.

The outline of one embodiment of the present invention is as follows.
A rotary impact tool (1) according to an aspect of the present invention includes a drive unit (10), a spindle (11) rotated by the drive unit, an anvil (22) disposed in front of the spindle in the rotation axis direction, The first steel between the main hammer (20) that can rotate about the rotation axis of the spindle and move in the direction of the rotation axis, and the guide groove (11b) on the spindle side and the engagement groove (20b) on the main hammer side. A cam structure in which a ball (19) is arranged, a sub-hammer (21) that accommodates the main hammer and is rotatable together with the main hammer, and a spindle portion provided on the rear side of the guide groove and formed with the guide groove A large diameter portion (16) having a larger outer diameter. The rotary impact tool of this aspect further includes a secondary hammer support structure in which the second steel ball (17) is disposed between the secondary hammer and the large diameter portion. In the secondary hammer support structure, the second steel ball (17) It arrange | positions between a subhammer and a large diameter part so that the load of a direction different from the radial direction orthogonal to a rotating shaft direction and a rotating shaft direction may be received.

The auxiliary hammer support structure has a structure in which a plurality of second steel balls (17) are arranged between the first holding groove (21g) on the auxiliary hammer side and the second holding groove (16a) on the large diameter side. It's okay. The cross section of the first holding groove and the second holding groove in the rotation axis direction may be arcuate, and the radius of the first holding groove and the second holding groove is larger than the radius of the second steel ball (17). Is preferred.

The second holding groove (16a) may be provided on the front outer periphery of the large diameter portion. The large-diameter portion may be a carrier (16) that is located on the rear end side of the spindle (11) and accommodates a power transmission gear.

DESCRIPTION OF SYMBOLS 1 ... Rotary impact tool, 10 ... Drive part, 11 ... Spindle, 11b ... Guide groove, 12 ... Power transmission mechanism, 16 ... Carrier, 16a ... 2nd holding groove , 17, 19 ... steel balls, 20 ... main hammer, 20b ... engagement groove, 21 ... sub-hammer, 21e ... annular partition, 21g ... first holding groove, 22 ... Anvil, 23 ... Spring member.

The present invention can be used in the field of rotary impact tools.

Claims

A drive unit, a spindle rotated by the drive unit, an anvil disposed in front of the spindle in the rotation axis direction, and a main hammer rotatable around the rotation axis of the spindle and movable in the rotation axis direction A cam structure in which a first steel ball is disposed between the guide groove on the spindle side and the engagement groove on the main hammer side; and a secondary hammer that accommodates the main hammer and is rotatable together with the main hammer. A rotary impact tool comprising a large diameter portion provided on a rear side of the guide groove and having a larger outer diameter than a portion of the spindle on which the guide groove is formed,
A secondary hammer support structure in which a second steel ball is disposed between the secondary hammer and the large diameter portion;
In the secondary hammer support structure, the second steel ball is disposed between the secondary hammer and the large diameter portion so as to receive a load in a direction different from a rotational axis direction and a radial direction orthogonal to the rotational axis direction. The
Rotating impact tool characterized by that.
The auxiliary hammer support structure is a structure in which a plurality of second steel balls are arranged between the first holding groove on the auxiliary hammer side and the second holding groove on the large diameter portion side.
The rotary impact tool according to claim 1.
Cross sections in the rotation axis direction of the first holding groove and the second holding groove are arcuate,
The rotary impact tool according to claim 2.
A radius of the first holding groove and the second holding groove is larger than a radius of the second steel ball,
The rotary impact tool according to claim 3.
The second holding groove is provided on the outer periphery of the front surface of the large diameter portion.
The rotary impact tool according to any one of claims 2 to 4, wherein:
The large-diameter portion is a carrier that is positioned on the rear end side of the spindle and accommodates a power transmission gear.
The rotary impact tool according to any one of claims 1 to 5.