CN115768598A - Impact rotary tool - Google Patents

Abstract

An object of the present disclosure is to reduce the tool size in the axial direction of the drive shaft. An impact rotary tool (1) includes a drive shaft (4), a reduction mechanism (5), an output shaft (13), a hammer (11), a spring (12), and a bearing member (6). The speed reduction mechanism (5) transmits the rotational force of the shaft of the motor (31) to the drive shaft (4). The rotation of the drive shaft (4) is output to the output shaft (13), and the output shaft (13) transmits the rotation to the tip tool (B1). The hammer (11) is rotatably supported by the drive shaft (4) and strikes the output shaft (13). The spring (12) biases the hammer (11) toward the output shaft (13). The bearing member (6) rotatably supports the drive shaft (4). The bearing member (6) is located on the output shaft (13) side of the reduction mechanism (5) in the axial direction (A1) of the drive shaft (4).

Description

Impact Rotary Tool

technical field

The present disclosure relates generally to an impact rotary tool, and more particularly to an impact rotary tool for generating impact torque.

Background technique

Patent Document 1 discloses an impact rotary tool. The impact rotary tool includes an impact mechanism portion. The impact mechanism part includes: a drive shaft connected to the motor via a speed reducer; an anvil; a hammer for striking the anvil; and a hammer spring for urging the hammer toward the anvil. The rear end of the shaft portion of the drive shaft is held by a support fixed in the housing housing the speed reducer, and the front end of the support is rotatably provided through the anvil. The rear hole remains.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2009-172732

Contents of the invention

There is an increasing demand for further downsizing of impact rotary tools. In addition to this, there is a rising need to reduce the size of the tool in the axial direction along its drive shaft.

Accordingly, in view of the above background, it is an object of the present disclosure to provide an impact rotary tool that facilitates reduction in the size of the tool in the axial direction of its drive shaft.

An impact rotary tool according to an aspect of the present disclosure includes a drive shaft, a reduction mechanism, an output shaft, a hammer, a spring, and a bearing member. The reduction mechanism transmits the rotational force of the shaft of the motor to the drive shaft. The output shaft receives the rotational force from the drive shaft and transmits the rotational force to the end tool. The hammer is rotatably supported by the drive shaft and strikes the output shaft. The spring urges the hammer towards the output shaft. The bearing member rotatably supports the drive shaft. The bearing member is arranged closer to the output shaft than the reduction mechanism in the axial direction of the drive shaft.

Description of drawings

[ Fig. 1] Fig. 1 is a sectional view of a main part of an impact rotary tool according to an exemplary embodiment.

[ Fig. 2] Fig. 2 is an external view showing an impact rotary tool.

[ Fig. 3] Fig. 3 is a partially cutaway external view showing a main part of the impact rotary tool.

[ Fig. 4] Fig. 4 is an exploded perspective view showing a drive shaft, an enlarged diameter portion, an extension portion, and a bearing member of the impact rotary tool.

[ Fig. 5] Fig. 5 is a perspective view showing a drive shaft and an enlarged diameter portion of the impact rotary tool.

[ Fig. 6] A of Fig. 6 is a perspective view showing oblique observation from the front of the main part of the impact rotary tool. B of FIG. 6 is a perspective view showing an oblique view from the rear of the main part of the impact rotary tool.

Detailed ways

(1 Overview

The drawings referred to in the following description of the embodiments are all schematic representations. Therefore, ratios of dimensions (including thicknesses) of respective constituent elements shown in the drawings do not always reflect their actual size ratios.

As shown in FIG. 1 , an impact rotary tool 1 according to the exemplary embodiment includes a drive shaft 4 , a reduction mechanism 5 , an output shaft 13 , a hammer 11 , a spring 12 and a bearing member 6 .

The reduction mechanism 5 transmits the rotational force of the shaft (rotation shaft 310 ) of the motor 31 to the drive shaft 4 . In the present embodiment, the reduction mechanism 5 is a planetary gear mechanism, and converts the rotational speed and torque of the rotating shaft 310 of the motor 31 into the rotational speed and torque required for the operation of turning the screw.

The output shaft 13 receives the rotational force from the drive shaft 4 and transmits the rotational force to the end tool B1. The hammer 11 is rotatably supported by the drive shaft 4 and strikes the output shaft 13 . Specifically, when the drive shaft 4 rotates, the hammer 11 strikes the impact receiving portion 14 (ie, the anvil) of the output shaft 13 . The spring 12 urges the hammer 11 toward the output shaft 13 . The bearing member 6 rotatably supports the drive shaft 4 . In the present embodiment, the bearing member 6 is, for example, the support C1. In the present embodiment, as shown in FIG. 1 , the bearing member 6 is arranged closer to the output shaft 13 than the reduction mechanism 5 in the axial direction A1 of the drive shaft 4 .

According to this configuration, the bearing member 6 is arranged closer to the output shaft 13 than the reduction mechanism 5 , and therefore, there is no need to leave a space for arranging the bearing member 6 on the opposite side of the output shaft 13 with respect to the reduction mechanism 5 . This contributes to reducing the dimension of the tool along the axial direction A1 of the drive shaft 4 .

(2) Details

(2.1) Overall structure

Next, the overall configuration of the impact rotary tool 1 according to the present embodiment will be described in detail.

In the following description, an exemplary embodiment will be described in which three axes (ie, X-axis, Y-axis, and Z-axis) crossing each other at right angles are defined as shown in FIGS. 1 to 4 . Specifically, in the exemplary embodiment to be described below, an axis coincident with an axis direction A1 (refer to FIG. 1 ) of the drive shaft 4 of the impact rotary tool 1 is defined herein as "X axis". In addition, the axis coincident with the arrangement direction of the barrel 21 and the base 23 of the housing 2 (to be described later) of the impact rotary tool 1 is defined herein as "Y axis". In the following description, the direction coincident with the X-axis will hereinafter be simply referred to as "front-rear direction". The negative side of the X-axis will hereinafter be simply referred to as "front", and the positive side of the X-axis will be hereinafter simply referred to as "rear". In addition, the direction coincident with the Y axis will hereinafter be simply referred to as "up and down direction", the positive side of the Y axis will be hereinafter simply referred to as "upper", and the negative side of the Y axis will be hereinafter simply referred to as "below".

Note that the X-axis, Y-axis and Z-axis are all imaginary axes, and the arrows indicating these X-axis, Y-axis and Z-axis on the drawings are shown there only as an aid of explanation and are intangible. It should also be noted that these directions do not limit the directions in which the impact rotary tool 1 should be used.

The impact rotary tool 1 is a portable electric tool that can be held by a user with one hand. The impact rotary tool 1 includes a motor block 3 (refer to FIG. 3 ), a drive block 10 (transmission mechanism, refer to FIGS. 1 and 3 ), and a housing 2 (refer to FIG. 2 ). The driving block 10 transmits the rotational force of the rotating shaft 310 (refer to FIG. 1 ) of the motor 31 in the motor block 3 to the end tool B1. The casing 2 accommodates the motor block 3 and the drive block 10 .

The impact rotary tool 1 also includes a holding portion 7 (sleeve mounting portion, refer to FIGS. 1-3 ) to hold a bit (such as a screwdriver) serving as an end tool B1 on the holding portion 7 . The end tool B1 is detachably attached to the holder 7 . The drive block 10 drives the tip tool B1 using the rotational force generated by the motor 31 . The driving mass 10 according to the present embodiment includes an impact mechanism IM1 (refer to FIG. 1 ). Note that the drive block 10 will be described in detail in the next section.

The impact rotary tool 1 according to the present embodiment may be an impact screwdriver that allows a user to perform work of fastening a screw B2 (refer to FIG. 2 ) with an impact force applied by the impact mechanism IM1.

A rechargeable battery pack 9 (see FIG. 2 ) is detachably attached to the impact rotary tool 1 . The impact rotary tool 1 is powered by a battery pack 9 . In this embodiment, the battery pack 9 is not a component of the impact rotary tool 1 . However, this is only an example and should not be construed as limiting. Alternatively, the impact rotary tool 1 may include a battery pack 9 as a constituent element. The battery pack 9 includes an assembled battery formed by connecting a plurality of secondary batteries such as lithium ion batteries in series, and a battery pack case 90 housing the assembled battery. The battery pack 9 includes a communication connector for transmitting battery information about the battery pack 9 . Examples of battery information include various information on temperature, battery capacity, rated voltage, rated capacity, and the number of charging times.

As shown in FIG. 2 , the housing 2 includes a barrel 21 , a grip 22 and a base 23 . The cylindrical body 21 has a hollow cylindrical shape. The grip portion 22 protrudes from the outer peripheral surface of the cylindrical body 21 in one direction (downward) coincident with the radial direction of the cylindrical body 21 . The grip portion 22 is formed in a hollow cylindrical shape long in the one direction. The inner space of the grip portion 22 communicates with the inner space of the barrel 21 . The barrel 21 is connected to one end (ie, upper end) in the length direction of the grip portion 22 , and the base portion 23 is connected to the other end (ie, lower end) in the length direction of the grip portion 22 . The battery pack 9 is detachably attached to the base 23 .

As shown in FIG. 2 , the impact rotary tool 1 further includes a switch circuit module 81 , an operating member 82 , a forward and reverse switching switch 83 and a control circuit module 84 .

The switch circuit module 81 is arranged in the inner space of the grip 22 . The switch loop module 81 is electrically connected to the control loop module 84 . The control circuit module 84 is housed in the base 23 .

The switch loop module 81 includes a main switch. The main switch is used to open and close an electric power supply path for supplying electric power from the battery pack 9 to the motor 31 . The operating member 82 is a trigger lever operated with one finger by the user of the impact rotary tool 1 . The operating member 82 is operatively coupled to the switch circuit module 81 . When the user operates with one finger, the operation member 82 is pulled toward the grip portion 22 .

When the operating member 82 is pulled to a depth equal to or less than a predetermined value, the switch circuit module 81 turns off the main switch, but when the operating member 82 is pulled to a depth greater than the predetermined value, the switch circuit module 81 turns on the main switch. This allows the switch circuit module 81 to selectively supply or cut off power from the battery pack 9 to the motor 31 . In addition, when the operating member 82 is pulled to a depth greater than a predetermined value, the switch circuit module 81 also transmits an operation signal corresponding to the pulled depth of the operating member 82 to the control circuit module 84 . This causes the magnitude of electric power supplied to the motor 31 to vary according to the depth to which the operation member 82 has been pulled, thereby varying the rotational speed of the rotary shaft 310 of the motor 31 .

In addition, the switch loop module 81 is also connected to a forward and reverse switching switch 83 . The forward and reverse switch 83 is a direction switch that allows the user to change the rotation direction of the rotation shaft 310 of the motor 31 . The forward and reverse switch 83 is provided near the boundary between the barrel 21 and the grip 22 .

The control loop module 84 is connected to the switching loop module 81 and the motor 31 . With the battery pack 9 mounted to the impact rotary tool 1 , the control circuit module 84 is connected to a pair of power terminals and a communication connector of the battery pack 9 . This allows the control circuit module 84 to be supplied with power from the battery pack 9 via a pair of power terminals. In addition, the control loop module 84 acquires battery information from the battery pack 9 via the communication connector. In addition, the control loop module 84 controls the motor 31 according to the operation signal supplied from the switch loop module 81 . More specifically, the control loop module 84 controls parameters such as the rotation speed and the rotation direction of the rotation shaft 310 of the motor 31 .

The motor block 3 is accommodated in the internal space of the cylindrical body 21 of the casing 2 so as to be located on the positive side of the X-axis. The motor block 3 is fixed to the casing 2 . The cylinder body 21 has a plurality of ventilation holes 211, 212 surrounding the motor block 3 (refer to FIG. 2 ).

As shown in FIG. 3 , the motor block 3 includes a motor 31 , a fan 32 and a drive circuit module 33 .

The motor 31 is a brushless motor. The motor 31 includes a motor body 311 (see FIG. 3 ) and a rotary shaft 310 (see FIG. 1 ) held rotatably by the motor body 311 .

The fan 32 has a plurality of blades. The fan 32 is coupled to the rotation shaft 310 of the motor 31 . This allows the fan 32 to rotate together with the rotation shaft 310 of the motor 31 .

The drive loop module 33 is controlled by the control loop module 84 to drive the motor 31 . The drive circuit module 33 includes a circuit board, a plurality of transistors mounted on the circuit board, and a packaging part for packaging the circuit board and the plurality of transistors together.

The rotation shaft 310 of the motor 31 is supported by the drive block 10 . The rotational force (driving force) generated by the rotor of the motor body 311 is transmitted from the rotational shaft 310 to the driving block 10 .

(2.2) Driver block

Next, the drive block 10 will be explained in detail. The drive block 10 is accommodated in the internal space of the cylindrical body 21 of the casing 2 so as to be located on the negative side of the X-axis with respect to the motor block 3 .

As shown in FIG. 1 , the drive block 10 includes a drive shaft 4 , a speed reduction mechanism 5 , a bearing member 6 , a hammer 11 , a spring 12 , an output shaft 13 , a case 15 , two steel balls 16 and an end side bearing member 17 .

The output shaft 13 is configured to receive the rotational force of the drive shaft 4 and transmit the rotational force to the end tool B1. The output shaft 13 is arranged in front of the drive shaft 4 (ie, on the negative side of the X-axis with respect to the drive shaft 4 ) such that its center axis substantially coincides with that of the drive shaft 4 . As shown in FIG. 1 , the output shaft 13 is formed such that a spindle 13A and an impact receiving portion 14 (anvil) are continuous and integral with each other. In the impact rotary tool 1 , the tip of the spindle 13A doubles as a part of the holding portion 7 , thereby allowing the tip tool B1 to be fixed on the tip of the spindle 13A.

The tip side bearing member 17 is configured as a support. The spindle 13A is rotatably supported by a tip-side bearing member 17 . The outer peripheral surface of the spindle 13A has a groove for fitting the O-ring G1. The spindle 13A is stably held by the inner ring of the tip side bearing member 17 via the O-ring G1 . Furthermore, the spindle 13A is also coupled to the drive shaft 4 . Thus, the spindle 13A rotates together with the drive shaft 4 . Note that the drive shaft 4 is rotatably supported by a bearing member 6 (described later).

The rotation shaft 310 of the motor 31 is coupled to the reduction mechanism 5 . The rotational force of the rotational shaft 310 of the motor 31 is transmitted to the drive shaft 4 via the reduction mechanism 5 . In the drive block 10 , the impact mechanism IM1 is formed by the drive shaft 4 , the hammer 11 , the spring 12 , the output shaft 13 and two steel balls 16 . The rotational force of the rotational shaft 310 of the motor 31 is transmitted to the spindle 13A of the output shaft 13 by the impact mechanism IM1 .

The reduction mechanism 5 transmits the rotational force of the rotational shaft 310 of the motor 31 to the drive shaft 4 . Specifically, the reduction mechanism 5 is a planetary gear mechanism for converting the rotational speed and torque of the rotating shaft 310 of the motor 31 into rotational speed and torque required for performing an operation of turning a screw. The reduction mechanism 5 includes a ring gear 51 , a sun gear 52 and three planetary gears 53 . As shown in FIG. 1 , the sun gear 52 is continuous and integral with the rotation shaft 310 of the motor 31 . Three planetary gears 53 mesh with the sun gear 52 on the outside of the sun gear 52 . As shown in B of FIG. 6 , the ring gear 51 meshes with and supports the three planetary gears 53 .

The hammer 11 is rotatably supported by the drive shaft 4 , and strikes the impact receiving portion 14 of the output shaft 13 . The hammer 11 includes a substantially cylindrical hammer body 110 which is flattened in the X-axis direction as a whole. The hammer body 110 has a through hole 111 through which the drive shaft 4 penetrates in the X-axis direction. The hammer body 110 has a groove 112 on the inner peripheral surface of the through hole 111 . Two steel balls 16 are sandwiched between the groove 112 and the groove 43 provided on the outer peripheral surface of the body 40 of the drive shaft 4 .

The groove 112, the groove 43 and the two steel balls 16 together form a cam mechanism. When the two steel balls 16 roll in the groove 43 , the hammer 11 can not only move along the axial direction A1 of the drive shaft 4 but also rotate relative to the drive shaft 4 . In the drive block 10, when the hammer 11 rotates relative to the drive shaft 4, the hammer 11 moves (ie, moves forward) or away from the spindle 13A of the output shaft 13 along the axis direction A1 of the drive shaft 4 according to its rotation angle. The spindle 13A of the output shaft 13 moves (ie, moves backward).

Note that lubricant is applied to, for example, the reduction mechanism 5 or the like. Lubricant is used to reduce friction and wear of drive block 10, for example. Lubricants are electrically insulating. For example, the lubricant may be a synthetic hydrocarbon oil grease.

As shown in FIG. 1 , FIG. 4 , A of FIG. 6 and B of FIG. 6 , the drive shaft 4 includes a body 40 , an enlarged diameter portion 41 and an extension portion 42 .

The body 40 supports the hammer 11 to be rotatable. The body 40 is formed in a cylindrical shape having a longitudinal axis coincident with the X-axis direction. For example, body 40 may be a metal part. The body 40 has an insertion recess 400 provided through an end face (ie, a front end face) of the body 40 on the negative side of the X-axis and recessed in the positive direction of the X-axis. A protrusion 130 (refer to FIG. 1 ) protruding rearward from a rear end surface of the output shaft 13 (ie, the rear end surface of the shock receiving portion 14 ) is inserted into the insertion recess 400 , thereby coupling the output shaft 13 to the drive shaft 4 . This allows the output shaft 13 to rotate together with the drive shaft 4 . Furthermore, the body 40 has a groove 43 to allow the two steel balls 16 to roll in the groove 43 as described above.

The enlarged diameter portion 41 is a portion protruding radially outward from the body 40 to position the spring 12 between the hammer 11 and the enlarged diameter portion 41 itself. The central axis of the enlarged diameter portion 41 is consistent with the central axis of the main body 40 . For example, the enlarged diameter part 41 may be a metal part. In addition, in the present embodiment, for example, the enlarged diameter portion 41 may be continuously and integrally formed with the main body 40 . In addition, the enlarged diameter portion 41 has a protrusion 411 protruding outward in the radial direction thereof (refer to FIGS. 1 and 4 ). The protrusion 411 may be a flange-like portion.

Specifically, the enlarged diameter portion 41 includes a first portion 41A, a second portion 41B, and three posts 41C.

When viewed in the X-axis direction, the first portion 41A has a plate-like shape. The peripheral portion 415 (see FIG. 5 ) of the first portion 41A protrudes in the X-axis negative direction along the entire circumference thereof. The first portion 41A is a cup-shaped portion as a whole. In other words, the first portion 41A has a positioning recess 410 (refer to FIG. 4 ) recessed rearward. The first portion 41A has a circular shape centered on the body 40 when viewed from the X-axis negative side. In addition, the above-described protruding portion 411 is provided for the first portion 41A. That is, the peripheral portion 415 of the first portion 41A protruding in the X-axis negative direction along the entire circumference has a flange shape protruding radially outward. The flange-like protrusion is the protrusion 411 .

The first portion 41A is continuously and integrally formed with the rear end portion of the body 40 and protrudes radially outward from the rear end portion of the body 40 . At the bottom of the positioning recess 410 is placed a ring-shaped sheet member T1 (refer to FIG. 1 and A of FIG. 6 ). The end portion of the spring 12 on the X-axis positive side is accommodated in the positioning recess 410 so as to be in contact with the front surface of the sheet member T1. That is, the spring 12 urges the bottom of the first portion 41A via the sheet member T1. This allows the end of the spring 12 on the X-axis positive side to be stably positioned relative to the drive shaft 4 .

As shown in FIGS. 4 and 5 , the first portion 41A has three shaft insertion holes 412 provided through the bottom thereof. The front ends (see B of FIG. 6 ) of the three shafts 530 of the three planetary gears 53 are respectively inserted into the three shaft insertion holes 412 . The sheet member T1 is arranged to cover the three shaft insertion holes 412 from the X-axis negative side. For example, the sheet member T1 may be made of felt. The sheet member T1 catches the lubricant applied to the speed reduction mechanism 5 and substantially prevents the lubricant from flowing to the outside of the speed reduction mechanism 5 . In addition, when the planetary gear 53 rotates, the plate member T1 reduces the possibility that the shaft 530 contacts and scratches its surrounding portion.

In addition, as shown in FIG. 1 , at the bottom of the positioning recess 410 , an annular elastic member S1 and an annular sheet member S2 covering the front surface of the elastic member S1 are arranged inside the sheet member T1 . If the hammer 11 moves in the X-axis positive direction by overcoming the elastic force exerted by the spring 12, the rear end portion of the hammer 11 will come into contact with the sheet member S2, thereby allowing the elastic member S1 to absorb the impact.

The second portion 41B is a disk-shaped portion whose thickness is aligned with the X-axis direction. The second portion 41B is arranged such that its front surface faces the rear surface of the first portion 41A. The three pillars 41C are parts that couple the first part 41A and the second part 41B to each other in a state where a predetermined distance is left between the first part 41A and the second part 41B. That is, the first portion 41A is continuously and integrally formed with the second portion 41B via the three pillars 41C. The three planetary gears 53 are accommodated in a gap SP1 (see FIG. 5 ) surrounded by the first portion 41A and the second portion 41B. Note that the three planetary gears 53 are accommodated in the gap SP1 , and their outer peripheral portions partially protrude from the gap SP1 to allow the three planetary gears 53 to mesh with the ring gear 51 . The gap SP1 is roughly equally divided into three spaces by the three columns 41C, and the three planetary gears 53 are housed in the three spaces, respectively.

The second part 41B has three shaft insertion holes 413 (refer to FIG. 5 ) provided through the second part 41B so as to face the three shaft insertion holes 412 of the first part 41A respectively in the X-axis direction. Respective rear end portions of the three shafts 530 of the three planetary gears 53 are inserted into the three shaft insertion holes 413 .

Thus, by inserting the three shafts 530 of the three planetary gears 53 into the three shaft insertion holes 412 of the first part 41A and the three shaft insertion holes 413 of the second part 41B, the three planetary gears 53 are moved by the enlarged diameter part 41 The support is rotatable.

As shown in FIG. 5, the second portion 41B has an insertion hole 414 as its center hole. In addition, the body 40 formed continuously and integrally with the first portion 41A has an undercut recess 401 provided through a central region of the rear end surface of the body 40 facing the insertion hole 414 as shown in FIG. 5 . The rotation shaft 310 of the motor 31 is inserted through the insertion hole 414 . In addition, the front end portion of the sun gear 52 formed continuously and integrally with the rotary shaft 310 is inserted into the undercut recess 401 without contacting the inner peripheral surface of the undercut recess 401 in a state of meshing with the three planetary gears 53 . middle.

Note that an annular sheet member (made of felt, for example) covering the three shaft insertion holes 413 from the X-axis positive side is also arranged on the rear surface of the second portion 41B. The annular sheet member and the sheet member T1 substantially prevent lubricant from flowing out of the reduction mechanism 5 . In addition, the annular plate member also reduces the possibility that the shaft 530 will contact and scratch its surroundings when the planetary gears 53 rotate.

The extension 42 is an annular portion. Specifically, the extension portion 42 has a cylindrical shape that is flat in the X-axis direction and has both ends open. For example, extension 42 may be a metal portion. The extension part 42 is at least separated from the main body 40 . In this embodiment, the enlarged diameter portion 41 is continuously and integrally formed with the main body 40 . Thus, the extension portion 42 is provided separately from both the main body 40 and the enlarged diameter portion 41 . The main body 40 and the enlarged diameter portion 41 are fitted and fixed into the extension portion 42 from the X-axis negative side (ie, from the front of the extension portion 42 ). In this case, the first part 41A is inserted to reach the rear opening of the extension 42 and fixed there to close the rear opening. Meanwhile, the second portion 41B, the three columns 41C, and the three planetary gears 53 housed in the gap SP1 are arranged behind the rear opening of the extension 42 . In this state, the three planetary gears 53 mesh with the ring gear 51 . As a result, the extension portion 42 extends from the edge portion of the enlarged diameter portion 41 toward the hammer 11 , as shown in FIG. 1 . The central axis of the extension part 42 is consistent with the central axis of the main body 40 .

The extension 42 is fitted and fixed into the bearing member 6 . In the present embodiment, the bearing member 6 is configured as a support C1 which will be described later. Thus, the extension 42 is arranged inside the inner ring 61 of the bearing C1 and is supported by the bearing C1 to rotate together with the inner ring 61 as shown in FIGS. 1 , A of FIG. 6 , and B of FIG. 6 . Thus, the body 40 is rotatably supported by the bearing member 6 via the enlarged diameter portion 41 and the extension portion 42 .

When the sun gear 52 continuous and integral with the rotation shaft 310 of the motor 31 rotates, the three planetary gears 53 also rotate within the ring gear 51 along the circumferential direction of the ring gear 51 . As a result, the body 40 , the enlarged diameter portion 41 and the extension portion 42 rotate together with each other.

As shown in FIGS. 1 and 4 , the extension portion 42 has an outer protrusion 421 protruding outward along its radial direction. The outer protrusion 421 is a flange-shaped portion. Specifically, the outer protrusion 421 protrudes outward from the front peripheral portion of the extension portion 42 along the entire circumference of the extension portion 42 . Further, the extension 42 is positioned by hooking the outer protrusion 421 from the side where the output shaft 13 is located (ie, from the front of the extension 42 ) onto the end surface 610 of the inner race 61 facing the output shaft 13 . This makes it easier to regulate movement of the extension 42 relative to the bearing member 6 away from the output shaft 13 (ie, rearward movement of the extension 42 ).

In addition, as shown in FIGS. 1 and 4 , the extension portion 42 also has an inner protrusion 422 protruding inward along its radial direction. Specifically, the inner protrusion 422 protrudes inward from the rear peripheral portion of the extension portion 42 along the entire circumference of the extension portion 42 . The enlarged diameter portion 41 is positioned by hooking the protrusion portion 411 onto the inner protrusion 422 from the side where the output shaft 13 is located (ie, from the front of the extension portion 42 ). This makes it easier to regulate the movement of the enlarged diameter portion 41 away from the output shaft 13 relative to the extension portion 42 (ie, the rearward movement of the enlarged diameter portion 41 ).

The bearing member 6 rotatably supports the drive shaft 4 . In particular, the bearing member 6 supports the drive shaft 4 in rotatable contact with the extension 42 . In the present embodiment, the bearing member 6 is arranged closer to the output shaft 13 than the reduction mechanism 5 in the axial direction A1 of the drive shaft 4 . In the present embodiment, the bearing member 6 is configured as a support C1. As shown in FIGS. 1 , 4 and B of FIG. 6 , the bearing member 6 includes an inner ring 61 , an outer ring 62 and a plurality of rolling elements (balls) 63 held between the inner ring 61 and the outer ring 62 . Note that, in the examples shown in FIG. 1 , FIG. 4 , and B of FIG. 6 , illustration of a cage for holding the plurality of rolling elements 63 between the inner ring 61 and the outer ring 62 is omitted.

Bearing member 6 rotatably supports drive shaft 4 in a state where at least a part of spring 12 (for example, an end of spring 12 on the X-axis positive side in this example) is arranged inside bearing member 6 . In other words, the bearing member 6 is arranged outside the spring 12 to surround the spring 12 with the inner ring 61 of the bearing member 6 .

In addition, the bearing member 6 is disposed between the hammer 11 and the reduction mechanism 5 along the axial direction A1 of the drive shaft 4 .

The spring 12 urges the hammer 11 toward the output shaft 13 . Specifically, the spring 12 is configured as a conical coil spring whose diameter decreases slightly along the positive direction of the X-axis. The spring 12 is disposed between the hammer 11 and the enlarged diameter portion 41 of the drive shaft 4 with the main body 40 of the drive shaft 4 inserted and passed through the spring 12 .

As shown in FIG. 1 , the impact mechanism IM1 also includes a plurality of steel balls 18 (only two of which are shown in FIG. 1 ) and a ring member 19, all of which are clamped between the hammer 11 and the spring 12. between. The hammer body 110 has a concave portion 113 on the positive side of the X-axis (ie, the rear end surface) to accommodate the end of the spring 12 on the negative side of the X-axis (see FIG. 1 ). The recess 113 is a circular recess recessed in the X-axis negative direction when viewed from the X-axis positive side. A plurality of steel balls 18 are arranged in the annular recess 113 along the circumferential direction of the annular recess 113 . In addition, the ring member 19 is arranged in the concave portion 113 so as to cover the plurality of steel balls 18 from behind the steel balls 18 . The end portion of the spring 12 on the X-axis negative side is accommodated in the recess 113 while urging the ring member 19 forward. This makes the hammer 11 rotatable relative to the spring 12 . The hammer 11 receives an urging force from the spring 12 toward the impact receiving portion 14 of the output shaft 13 in a direction along the axis direction A1 of the drive shaft 4 .

The case 15 accommodates the drive shaft 4, the reduction mechanism 5, the bearing member 6, the hammer 11, the spring 12, the output shaft 13, two steel balls 16, and the like. The housing 15 has substantially the same shape as the end portion of the cylindrical body 21 of the housing 2 on the X-axis negative side (ie, the front end portion of the cylindrical body 21 ). With almost no gap left between the case 15 and the barrel 21 , the case 15 is formed in a size slightly smaller than the front end of the barrel 21 so that the case 15 fits into the front end of the barrel 21 .

As shown in FIG. 1 , the housing 15 includes a cover 15A and a mounting base 15B.

For example, the cover 15A may be made of alloy. The cover 15A has a cylindrical shape with both ends open in the X-axis direction. As shown in FIG. 1 , the cover 15A has a first opening 151 (as a front opening) and a second opening 152 (as a rear opening) at both ends thereof in the X-axis direction. The cover 15A is formed such that its diameter gradually decreases from the middle in the X-axis direction toward the first opening 151 so that the shorter the distance to the first opening 151, the smaller the diameter of the cover 15A. The opening area of the first opening 151 is smaller than the opening area of the second opening 152 .

The cover 15A accommodates the hammer 11 so as to completely surround the hammer 11 . In addition, the cover 15A accommodates the drive shaft 4 and the spring 12 so as to completely surround the drive shaft 4 and the spring 12 . In addition, the cover 15A accommodates the output shaft 13 so as to surround the output shaft 13 in a state where a part of the output shaft 13 (ie, its end on the X-axis negative side) protrudes from the first opening 151 .

The mounting base 15B has electrical insulation. For example, the mounting base 15B may be made of synthetic resin. The mounting base 15B basically has a cylindrical shape flattened in the X-axis direction as a whole. One end portion of the mounting base 15B on the X-axis negative side is open. A bottom 153 (refer to FIG. 1 ) of the mounting base 15B has a shaft hole 154 passing through the bottom 153 in the X-axis direction. The rotary shaft 310 of the motor 31 is arranged such that a tip portion thereof protrudes from the bottom portion 153 toward the X-axis negative side through-shaft hole 154 .

The mounting base 15B has an inner peripheral surface whose inner diameter decreases stepwise toward the bottom 153 . The stepped inner peripheral surface defines the first housing portion H1 and the second housing portion H2, the inner diameter of the second housing portion H2 is smaller than the inner diameter of the first housing portion H1. In other words, the inside of the mounting base 15B includes a first housing portion H1 and a second housing portion H2 .

The first accommodation portion H1 is configured to accommodate the bearing member 6 . The second housing portion H2 is configured to house the reduction mechanism 5 . The first receiving portion H1 is a space area defined inside the installation base 15B closer to the opening of the installation base 15B. The second receiving portion H2 is a space area defined inside the installation base 15B and closer to the bottom 153 . That is to say, the first housing portion H1 , the second housing portion H2 and the bottom portion 153 are arranged side by side in sequence along the positive direction of the X-axis.

The mounting base 15B holds the ring gear 51 of the reduction mechanism 5 in the second housing portion H2. For example, the ring gear 51 may be insert-molded with respect to the mounting base 15B. That is, the ring gear 51 is fixed to the mounting base 15B.

The mounting base 15B also holds the bearing member 6 in the first housing portion H1. The bearing member 6 is arranged such that its end portion on the X-axis negative side protrudes slightly in the X-axis negative direction with respect to the first housing portion H1 (see FIG. 1 ). The protruding portion of the bearing member 6 is held by the cover 15A.

Specifically, the cover 15A is formed such that the inner diameter of its inner peripheral surface adjacent to the second opening 152 (ie, the rear opening) decreases stepwise toward the front end of the cover 15A. In other words, the cover 15A has a first recess R1 and a second recess R2 on its inner peripheral surface adjacent to the second opening 152 , the second recess R2 having an inner diameter larger than that of the first recess R1 . The second recess R2 is located on the X-axis positive side relative to the first recess R1.

The cover 15A is assembled to the mounting base 15B by fitting the outer peripheral wall W1 (refer to FIG. 1 ) of the mounting base 15B into the second recess R2. The outer peripheral surface of the outer peripheral wall W1 has a groove for fitting the O-ring G2. Providing the O-ring G2 allows the cover 15A to be assembled to the mounting base 15B with good stability while reducing the chance of foreign matter such as dust or water entering the housing 15 through the gap between the outer peripheral wall W1 and the inner peripheral surface of the second recess R2. possibility.

In addition, as shown in FIG. 1 , the cover 15A and the mounting base 15B hold the bearing member 6 so as to sandwich the outer ring 62 of the bearing member 6 between the first recess R1 and the first housing portion H1 . Therefore, the bearing member 6 can be positioned within the housing 15 with good stability.

(2.3) Advantages

In the present embodiment, as shown by the imaginary line Y1 (dotted line) and the hollow arrow in FIG. In other words, it is located on the X-axis negative side with respect to the reduction mechanism 5). Thereby, there is no need to leave a space for arranging the bearing member 6 on the opposite side of the output shaft 13 with respect to the reduction mechanism 5 (that is, behind the reduction mechanism 5; in other words, on the X-axis positive side with respect to the reduction mechanism 5). . Furthermore, this makes it easier to arrange the bearing member 6 at the same position as the spring 12 along the axis direction A1. This contributes to reducing the dimension of the tool along the axial direction A1 of the drive shaft 4 .

In particular, when it is necessary to perform work above a ceiling, or when it is necessary to install a built-in kitchen, a flush toilet, or a modular bathroom, for example, the work space tends to be relatively narrow. Thus, among installers who often have to perform work of fastening screws using impact rotary tools in such a narrow work space, there is a markedly increased demand for reducing the size of the tool in the axial direction of the drive shaft. The impact rotary tool 1 according to the present embodiment adopts the configuration and structure for the bearing member 6 described above, thereby reducing the size of the tool, thereby greatly contributing to meeting such demands.

Furthermore, according to the present embodiment, with at least a part of the spring 12 arranged inside the bearing member 6 , the bearing member 6 rotatably supports the drive shaft 4 . That is, the bearing member 6 is disposed outside the spring 12 so as to surround the spring 12 . Thus, arranging the bearing member 6 in the space around the spring 12 that would normally tend to be unused space in the drive block 10 enables efficient use of the space around the spring 12, thereby making it easier to reduce the tool's The dimension of the axial direction A1. In addition, according to the present embodiment, the bearing member 6 is disposed between the hammer 11 and the reduction mechanism 5 along the axial direction A1 of the drive shaft 4, thereby making it possible to make more effective use of the space around the spring 12, thereby making it easier to reduce the The dimension of the tool along the axis direction A1.

In addition, the drive shaft 4 includes a body 40 , an enlarged diameter portion 41 and an extension portion 42 , thereby making it easier to realize such a configuration that the bearing member 6 is arranged closer to the output shaft 13 than the reduction mechanism 5 .

In particular, according to the present embodiment, the extension part 42 is provided separately from the body 40, thereby achieving the following advantages. Specifically, in the manufacturing process of the impact rotary tool 1 , the hammer 11 needs to slide smoothly (move with thrust) relative to the body 40 by subjecting the surface of the body 40 to surface treatment such as polishing. If the extension 42 and the body 40 are formed continuously and integrally with each other, the extension 42 will hinder surface treatment on the body 40 . In contrast, for example, providing the extension 42 separately from the body 40 as in the present embodiment makes it easier to perform surface treatment on the body 40 .

Furthermore, according to the present embodiment, the extension portion 42 includes the flange-shaped outer protrusion 421 and is positioned by hooking the outer protrusion 421 onto the end surface 610 of the inner ring 61 from the front. In addition, the extension portion 42 includes an inner protrusion 422 , and the enlarged diameter portion 41 is positioned by hooking the flange-shaped protrusion 411 onto the inner protrusion 422 from the front of the extension portion 42 .

In short, the two parts of the drive shaft 4, namely the extension part 42 and the diameter-enlarged part 41 formed continuously and integrally with the body 40, can be sequentially connected to each other in the same direction (in the rearward direction) with respect to the bearing member 6. connect. This enables more efficient assembly during manufacturing.

In addition, the two parts of the drive shaft 4 , namely the extension 42 and the enlarged diameter 41 formed continuously and integrally with the body 40 , are coupled to each other by regulating their rearward movement relative to the bearing member 6 . When the work of fastening a screw is performed using the impact rotary tool 1 , the impact rotary tool 1 receives a load applied in the X-axis forward direction (ie, in the rearward direction) from the target of the screw fastening work. In this respect, the impact rotary tool 1 has a coupling structure for regulating the rearward movement of the enlarged diameter portion 41 and the extension portion 42 , whereby a particularly reliable tool can be provided.

(3) Variations

Note that the above-described embodiments are only exemplary embodiments among various embodiments of the present disclosure, and should not be construed as limiting. Rather, the exemplary embodiments may be readily modified in various ways, depending on design choice or any other factors, without departing from the scope of the present disclosure.

Next, modifications of the exemplary embodiment will be listed one by one. In the following description, the above-described exemplary embodiment will hereinafter sometimes be referred to as a “basic example”. Note that each modification example to be described below can be employed in appropriate combination with the basic example or any other modification example.

In the basic example described above, the main body 40 and the enlarged diameter portion 41 are continuously and integrally formed in the drive shaft 4 . However, this is only an example and should not be construed as limiting. Alternatively, the body 40 and the enlarged diameter portion 41 may be provided separately from each other. For example, the enlarged diameter portion 41 and the extension portion 42 may be continuously and integrally formed with each other, but provided separately from the body 40 . Still alternatively, the body 40 , the enlarged diameter portion 41 and the extension portion 42 may all be continuously and integrally formed with each other.

In the basic example described above, the outer protrusion 421 of the extension portion 42 is formed along the entire circumference of the peripheral portion of the extension portion 42 . However, this is only an example and should not be construed as limiting. Alternatively, a plurality of outer protrusions 421 may be intermittently formed along the circumferential direction of the peripheral portion.

Also, in the basic example described above, the inner protrusion 422 of the extension portion 42 is formed along the entire circumference of the peripheral portion of the extension portion 42 . However, this is only an example and should not be construed as limiting. Alternatively, a plurality of inner protrusions 422 may be intermittently formed along the circumferential direction of the peripheral portion.

Likewise, in the basic example described above, the protruding portion 411 of the enlarged diameter portion 41 is formed along the entire circumference of the peripheral portion of the enlarged diameter portion 41 . However, this is only an example and should not be construed as limiting. Alternatively, the plurality of protrusions 411 may be intermittently formed along the circumferential direction of the peripheral portion.

In the basic example described above, the impact rotary tool 1 is an impact screwdriver as an example. However, the impact rotary tool 1 does not have to be an impact screwdriver, and may be, for example, an impact wrench.

(4) Summary

As can be seen from the foregoing description, the impact rotary tool (1) according to the first aspect includes a drive shaft (4), a reduction mechanism (5), an output shaft (13), a hammer (11), a spring (12) and a bearing member (6). The reduction mechanism (5) transmits the rotational force of the shaft (rotation shaft 310) of the motor (31) to the drive shaft (4). The output shaft (13) receives the rotational force from the drive shaft (4) and transmits the rotational force to the end tool (B1). The hammer (11) is rotatably supported by the drive shaft (4) and strikes the output shaft (13). The spring (12) urges the hammer (11) towards the output shaft (13). The bearing member (6) rotatably supports the drive shaft (4). The bearing member (6) is arranged closer to the output shaft (13) than the reduction mechanism (5) along the axis direction (A1) of the drive shaft (4). According to the first aspect, the bearing member (6) is arranged closer to the output shaft (13) than the reduction mechanism (5), thereby contributing to reducing the size of the tool along the axial direction (A1) of the drive shaft (4).

In the impact rotary tool (1) according to the second aspect which can be implemented in combination with the first aspect, with at least a part of the spring (12) arranged inside the bearing member (6), the bearing member (6) is rotatably supported drive shaft (4). The second aspect makes it easier to reduce the size of the tool.

In the impact rotary tool (1) according to the third aspect that can be implemented in combination with the first or second aspect, the bearing member (6) is arranged between the hammer (11) and the speed reducer along the axial direction (A1) of the drive shaft (4). between institutions (5). The third aspect makes it easier to reduce the size of the tool.

In the impact rotary tool (1) according to the fourth aspect which may be implemented in combination with any one of the first to third aspects, the drive shaft (4) includes a body (40) which supports the hammer (11) rotatably, An enlarged diameter portion (41) and an annular extension portion (42). The enlarged diameter portion (41) protrudes radially outward from the body (40) and is configured to position the spring (12) between the hammer (11) and the enlarged diameter portion (41) itself. The extension portion (42) extends from the edge portion of the enlarged diameter portion (41) toward the hammer (11). The bearing member (6) is in contact with the extension (42) to rotatably support the drive shaft (4). The fourth aspect makes it easier to realize a configuration in which the bearing member (6) is arranged closer to the output shaft (13) than the reduction mechanism (5).

In the impact rotary tool (1) according to the fifth aspect which can be implemented in combination with the fourth aspect, the enlarged diameter portion (41) is continuously and integrally provided with the body (40). The fifth aspect can reduce the increase in the number of required parts.

In the impact rotary tool (1) according to the sixth aspect which may be implemented in combination with the fourth or fifth aspect, the extension (42) is at least provided separately from the body (40). The sixth aspect makes it easier to carry out surface treatment, such as polishing treatment, on the body (40) than in an arrangement in which the extension (42) is continuously and integrally formed with the body (40).

In the impact rotary tool (1) according to the seventh aspect which can be implemented in combination with any one of the fourth to sixth aspects, the bearing member (6) is configured as a support (C1). The extension (42) is arranged inside the inner ring (61) of the bearing (C1), and is supported by the bearing (C1) to rotate together with the inner ring (61). The seventh aspect makes it easier to provide a configuration in which the bearing member (6) is arranged closer to the output shaft (13) than the reduction mechanism (5).

In the impact rotary tool (1) according to the eighth aspect that can be implemented in combination with the seventh aspect, the extension (42) includes an outer protrusion (421) protruding outward along the radial direction of the extension (42). Position the extension (42) by hooking the outer protrusion (421) of the extension (42) from the side where the output shaft (13) is located onto the end face (610) of the inner race (61) facing the output shaft (13) . The eighth aspect makes it easier to regulate the movement of the extension (42) relative to the bearing member (6) away from the output shaft (13).

In the impact rotary tool (1) according to the ninth aspect which can be carried out in combination with any one of the fourth to eighth aspects, the extension portion (42) is provided separately from the enlarged diameter portion (41). The extension part (42) includes an inner protrusion (422) protruding inward along the radial direction of the extension part (42). The enlarged diameter portion (41) includes a protrusion (411) protruding outward along the radial direction of the enlarged diameter portion (41). The enlarged diameter portion (41) is positioned by hooking the protrusion (411) of the enlarged diameter portion (41) onto the inner protrusion (422) from the side where the output shaft (13) is located. The ninth aspect makes it easier to regulate the movement of the enlarged diameter portion (41 ) relative to the extension portion (42) away from the output shaft (13).

Note that the constituent elements according to the second to ninth aspects are not basic constituent elements for the impact rotary tool (1), but may be appropriately omitted.

Explanation of reference signs

1 impact rotary tool

4 drive shafts

40 body

41 Expanded part

411 protrusion

42 extension

421 Outer protrusions

422 Inner protrusion

5 reduction mechanism

6 Bearing components

61 inner ring

610 end face

11 hammer

12 springs

13 output shaft

31 motor

310 axis of rotation

A1 axis direction

B1 end tool

C1 support

Claims (9)

1. An impact rotary tool comprising: drive shaft; a reduction mechanism configured to transmit a rotational force of a shaft of the motor to the drive shaft; an output shaft configured to receive rotational force from the drive shaft and transmit the rotational force to an end tool; a hammer rotatably supported by the drive shaft and configured to strike the output shaft; a spring that urges the hammer toward the output shaft; and a bearing member that rotatably supports the drive shaft, The bearing member is arranged closer to the output shaft than the reduction mechanism in the axial direction of the drive shaft. 2. The impact rotary tool according to claim 1, wherein: The bearing member rotatably supports the drive shaft in a state where at least a part of the spring is arranged inside the bearing member. 3. The impact rotary tool according to claim 1 or 2, characterized in that, The bearing member is arranged between the hammer and the reduction mechanism along the axis direction of the drive shaft. 4. An impact rotary tool according to any one of claims 1 to 3, characterized in that The drive shaft includes: a body supporting the hammer rotatably; an enlarged diameter portion projecting radially outward from the body and configured to position the spring between the hammer and the enlarged diameter portion itself; and an extension portion having a ring shape and extending toward the hammer from an edge portion of the enlarged diameter portion where it is located, and The bearing member is in contact with the extension to rotatably support the drive shaft. 5. The impact rotary tool of claim 4, wherein: The enlarged diameter portion is configured to be continuous and integrated with the body. 6. The impact rotary tool according to claim 4 or 5, characterized in that The extension is provided separately from at least the body. 7. An impact rotary tool according to any one of claims 4 to 6, characterized in that The bearing member is configured as a support, The extension is arranged inside the inner ring of the bearing and supported to rotate together with the inner ring by the bearing. 8. The impact rotary tool of claim 7, wherein: the extension includes an outer protrusion protruding outward along a radial direction of the extension, and The extension is positioned by hooking the outer protrusion of the extension from the side where the output shaft is located to the end face of the inner ring facing the output shaft. 9. An impact rotary tool according to any one of claims 4 to 8, characterized in that The extension part is set separately from the diameter-expanding part, The extension includes an inner protrusion protruding inward along a radial direction of the extension, The enlarged diameter portion includes a protrusion protruding outward along the radial direction of the enlarged diameter portion, and The enlarged diameter portion is positioned by hooking the protrusion from the side where the output shaft is located to the inner protrusion.

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