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

Patent document 1 discloses an impact rotary tool. The impact rotary tool includes an impact mechanism portion. The impact mechanism portion includes: a drive shaft connected to the motor via a speed reducer; an anvil block; a hammer for striking the anvil; 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 a housing that houses the speed reducer, and the front end of the support is rotatably held by a rear hole provided through the anvil.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2009-172732

Disclosure of Invention

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

Therefore, 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 dimension 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 speed reduction mechanism, an output shaft, a hammer, a spring, and a bearing member. The speed 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 tip tool. The hammer is supported by the drive shaft to be rotatable and to strike the output shaft. The spring applies a force to the hammer toward the output shaft. The bearing member rotatably supports the drive shaft. The bearing member is disposed closer to the output shaft than the reduction mechanism in the axial direction of the drive shaft.

Drawings

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

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

Fig. 3 is a partial sectional external view showing a main part of an impact rotary tool.

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

Fig. 6 a is a perspective view showing a main portion of the impact rotary tool viewed obliquely from the front. B of fig. 6 is a perspective view showing an oblique view from the rear of the main portion of the impact rotary tool.

Detailed Description

(1) Overview

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

As shown in fig. 1, the impact rotation tool 1 according to the exemplary embodiment includes a drive shaft 4, a speed 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 (the rotational shaft 310) of the motor 31 to the drive shaft 4. In the present embodiment, the speed reduction mechanism 5 is a planetary gear mechanism, and converts the rotation speed and torque of the rotary shaft 310 of the motor 31 into the rotation 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 tip tool B1. The hammer 11 is rotatably supported by the drive shaft 4 and strikes an output shaft 13. Specifically, when the drive shaft 4 rotates, the hammer 11 strikes an impact receiving portion 14 (i.e., an 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, a bearing C1. In the present embodiment, as shown in fig. 1, the bearing member 6 is disposed closer to the output shaft 13 than the reduction mechanism 5 along the axial direction A1 of the drive shaft 4.

According to this configuration, the bearing member 6 is disposed closer to the output shaft 13 than the reduction mechanism 5, and therefore, it is not necessary to leave a space for disposing the bearing member 6 on the opposite side of the output shaft 13 with respect to the reduction mechanism 5. This contributes to a reduction in the size of the tool in the axial direction A1 of the drive shaft 4.

(2) Details of

(2.1) general construction

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 (i.e., X, Y, and Z axes) intersecting each other at right angles are defined as shown in fig. 1 to 4. Specifically, in the exemplary embodiment to be described below, a shaft that coincides with the axial direction A1 (refer to fig. 1) of the drive shaft 4 of the impact rotation tool 1 is defined herein as an "X-axis". In addition, an axis that coincides with the arrangement direction of the cylinder 21 and the base 23 of the housing 2 (described later) of the impact rotation tool 1 is defined herein as a "Y axis". In the following description, the direction coinciding with the X axis will hereinafter be referred to simply as "front-rear direction". The negative side of the X-axis will hereinafter be referred to simply as "front", while the positive side of the X-axis will hereinafter be referred to simply as "rear". In addition, the direction coinciding with the Y axis will hereinafter be referred to simply as "up-down direction", the positive side of the Y axis will hereinafter be referred to simply as "upper", and the negative side of the Y axis will hereinafter be referred to simply as "lower".

Note that X, Y, and Z axes are imaginary axes, and arrows indicating these X, Y, and Z axes on the drawings are shown there merely as an aid of illustration, and are not solid. It should also be noted that these directions do not define the direction in which the impact rotary tool 1 should be used.

The impact rotation tool 1 is a portable electric power tool that can be grasped by a user with one hand. The impact rotation tool 1 includes a motor block 3 (see fig. 3), a drive block 10 (transmission mechanism, see fig. 1 and 3), and a housing 2 (see fig. 2). The driving block 10 transmits the rotational force of the rotational shaft 310 (refer to fig. 1) of the motor 31 in the motor block 3 to the tip tool B1. The housing 2 accommodates the motor block 3 and the drive block 10.

The impact rotation tool 1 further includes a holding portion 7 (sleeve mounting portion, refer to fig. 1 to 3) to hold a bit (such as a screwdriver) serving as the tip tool B1 on the holding portion 7. The end tool B1 is detachably attached to the holding portion 7. The driving block 10 drives the tip tool B1 using the rotational force generated by the motor 31. The drive block 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 following section.

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

A rechargeable battery pack 9 (see fig. 2) is detachably attached to the impact rotary tool 1. The impact rotation tool 1 is powered by a battery pack 9. In the present embodiment, the battery pack 9 is not a component of the impact rotary tool 1. However, this is merely an example and should not be construed as limiting. Alternatively, the impact rotary tool 1 may include the 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 pack case 90 that houses the assembled battery. The battery pack 9 includes a communication connector for transmitting battery information about the battery pack 9. Examples of the battery information include various information on temperature, battery level, rated voltage, rated capacity, and number of charges.

As shown in fig. 2, the housing 2 includes a cylinder 21, a grip 22, and a base 23. The cylinder 21 has a hollow cylindrical shape. The grip portion 22 protrudes from the outer peripheral surface of the cylinder 21 in one direction (downward) that coincides with the radial direction of the cylinder 21. The grip portion 22 is formed in a hollow cylindrical shape long in the one direction. The inner space of the grip 22 communicates with the inner space of the cylinder 21. The cylinder 21 is connected to one end (i.e., an upper end) of the grip portion 22 in the longitudinal direction, and the base 23 is connected to the other end (i.e., a lower end) of the grip portion 22 in the longitudinal direction. The battery pack 9 is removably mounted to the base 23.

As shown in fig. 2, the impact rotary tool 1 further includes a switch circuit module 81, an operation member 82, a forward-reverse changeover switch 83, and a control circuit module 84.

The switch circuit module 81 is disposed in the inner space of the grip portion 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 by a user of the impact rotation tool 1 with one finger. The operating member 82 is operatively coupled to the switch circuit module 81. When the user operates with one finger, the operating member 82 is pulled toward the grip portion 22.

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

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

The control loop module 84 is connected to the switching loop module 81 and the motor 31. In the case where the battery pack 9 is 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 loop module 84 to be supplied with power from the battery pack 9 via a pair of power terminals. Further, the control circuit module 84 acquires battery information from the battery pack 9 via the communication connector. In addition, the control circuit module 84 controls the motor 31 according to the operation signal supplied from the switching circuit module 81. More specifically, the control circuit module 84 controls parameters such as the rotational speed and the rotational direction of the rotating shaft 310 of the motor 31.

The motor block 3 is accommodated in the inner space of the cylindrical body 21 of the housing 2 so as to be positioned on the positive side of the X axis. The motor block 3 is fixed to the housing 2. The cylinder 21 has a plurality of vent holes 211, 212 (see fig. 2) surrounding the motor block 3.

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 by the motor body 311 to be rotatable.

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

The drive circuit module 33 is controlled by the control circuit module 84 to drive the motor 31. The driving circuit module 33 includes a circuit board, a plurality of transistors mounted on the circuit board, and a packaging portion that packages the circuit board and the plurality of transistors together.

The rotation shaft 310 of the motor 31 is supported by the driving 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) drive Block

Next, the driving block 10 will be explained in detail. The drive block 10 is accommodated in the inner space of the cylinder 21 of the housing 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 housing 15, two steel balls 16, and a distal 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 tip tool B1. The output shaft 13 is disposed in front of the drive shaft 4 (i.e., disposed on the negative side of the X-axis with respect to the drive shaft 4) in such a manner that its central axis substantially coincides with the central axis of the drive shaft 4. As shown in fig. 1, the output shaft 13 is formed such that the spindle 13A and the impact receiving portion 14 (anvil) are continuous and integral with each other. In the impact rotation 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 the tip-side bearing member 17. The outer peripheral surface of the spindle 13A has a groove in which an O-ring G1 is fitted. The spindle 13A is stably held by the inner ring of the distal end side bearing member 17 via the O-ring G1. Further, the spindle 13A is also coupled to the drive shaft 4. Thereby, 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 rotating shaft 310 of the motor 31 is coupled to the speed reduction mechanism 5. The rotational force of the rotating shaft 310 of the motor 31 is transmitted to the drive shaft 4 via the speed reduction mechanism 5. In the drive block 10, an 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 IM 1.

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

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

Together, the slot 112, the slot 43 and the two steel balls 16 form a cam mechanism. When the two steel balls 16 roll in the grooves 43, the hammer 11 can move not only in 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 toward the spindle 13A of the output shaft 13 (i.e., moves forward) or away from the spindle 13A of the output shaft 13 (i.e., moves backward) in the axial direction A1 of the drive shaft 4 according to the rotation angle thereof.

Note that the lubricant is applied to, for example, the speed reduction mechanism 5 or the like. The lubricant is used to reduce friction and wear of, for example, the drive block 10. The lubricant has electrical insulation properties. For example, the lubricant may be a synthetic hydrocarbon oil grease.

As shown in fig. 1, 4, a of fig. 6, and B of fig. 6, the drive shaft 4 includes a main body 40, an enlarged diameter portion 41, and an extended 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 coinciding with the X-axis direction. For example, the body 40 may be a metal part. The body 40 has an insertion recess 400, and the insertion recess 400 is provided through an end surface (i.e., a front end surface) of the body 40 on the X-axis negative side and recessed in the X-axis positive direction. A protrusion 130 (refer to fig. 1) protruding rearward from a rear end surface of the output shaft 13 (i.e., a rear end surface of the impact 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. In addition, the body 40 has a slot 43 to allow the two steel balls 16 to roll in the slot 43 as described above.

The enlarged diameter portion 41 is a portion that protrudes radially outward from the body 40 to position the spring 12 between the hammer 11 and the enlarged diameter portion 41 itself. The center axis of the enlarged diameter portion 41 coincides with the center axis of the main body 40. For example, the enlarged diameter portion 41 may be a metal portion. In the present embodiment, for example, the enlarged diameter portion 41 may be formed continuously and integrally with the main body 40. Further, the diameter-enlarged portion 41 has a projection 411 (refer to fig. 1 and 4) projecting outward in the radial direction thereof. 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 columns 41C.

The first portion 41A has a plate-like shape when viewed in the X-axis direction. The peripheral edge portion 415 (see fig. 5) of the first portion 41A protrudes in the negative X-axis 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. Further, the above-described protrusion 411 is provided for the first portion 41A. That is, the peripheral portion 415 of the first portion 41A, which protrudes in the X-axis negative direction along the entire circumference, has a flange shape that protrudes radially outward. The flange-like projection is a protrusion 411.

The first portion 41A is continuously and integrally formed with the rear end portion of the body 40, and projects radially outward from the rear end portion of the body 40. A circular ring-shaped piece member T1 (see a in fig. 1 and 6) is placed on the bottom of the positioning recess 410. The end of the spring 12 on the X-axis positive side is housed 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 with respect to the drive shaft 4.

As shown in fig. 4 and 5, the first portion 41A has three shaft insertion holes 412 provided through the bottom thereof. The tip portions (see B in fig. 6) of the three shafts 530 of the three planetary gears 53 are inserted into the three shaft insertion holes 412, respectively. 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 captures the lubricant applied to the speed reducing mechanism 5 and substantially prevents the lubricant from flowing to the outside of the speed reducing mechanism 5. Further, when the planetary gear 53 rotates, the sheet member T1 reduces the possibility that the shaft 530 contacts and scratches the surrounding portion thereof.

As shown in fig. 1, at the bottom of the positioning recess 410, a circular elastic member S1 and a circular sheet member S2 covering the front surface of the elastic member S1 are disposed inside the sheet member T1. If the hammer 11 is moved in the X-axis positive direction by overcoming the elastic force applied 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 disc-shaped portion whose thickness is aligned with the X-axis direction. The second portion 41B is arranged with its front surface facing the rear surface of the first portion 41A. The three columns 41C are portions that couple the first portion 41A and the second portion 41B to each other with a predetermined distance left between the first portion 41A and the second portion 41B. That is, the first portion 41A is continuously and integrally formed with the second portion 41B via the three posts 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 pinion gears 53 are housed in the gap SP1, and their outer peripheral portions partially protrude from the gap SP1 to allow the three pinion gears 53 to mesh with the ring gear 51. The gap SP1 is substantially equally divided into three spaces by the three columns 41C, and the three planetary gears 53 are respectively accommodated in the three spaces.

The second part 41B has three shaft insertion holes 413 (refer to fig. 5) provided through the second part 41B to face the three shaft insertion holes 412 of the first part 41A, respectively, one to one 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, the three planetary gears 53 are supported by the diameter-enlarged portion 41 to be rotatable 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.

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

Note that a circular ring-shaped 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 the lubricant from flowing out of the speed reducing mechanism 5. Further, the circular ring-shaped piece member also reduces the possibility that the shaft 530 contacts and scratches its surrounding portion when the planetary gear 53 rotates.

The extension 42 is an annular portion. Specifically, the extension 42 has a cylindrical shape that is flat in the X-axis direction and open at both ends. For example, the extension 42 may be a metal part. The extension 42 is provided at least separately from the body 40. In the present embodiment, the enlarged diameter portion 41 is formed continuously and integrally with the main body 40. Thereby, the extension portion 42 is provided separately from both the body 40 and the enlarged diameter portion 41. The body 40 and the enlarged diameter portion 41 are fitted and fixed into the extended portion 42 from the X-axis negative side (i.e., from the front of the extended portion 42). In this case, the first portion 41A is inserted to reach the rear opening of the extension 42 and fixed thereto to close the rear opening. Meanwhile, the second portion 41B, the three posts 41C, and the three planetary gears 53 accommodated in the gap SP1 are arranged rearward of the rear opening of the extending portion 42. In this state, the three pinion gears 53 mesh with the ring gear 51. As a result, the extending 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 42 coincides with the central axis of the 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 bearing C1 to be described later. Thereby, 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 fig. 1, a of fig. 6, and B of fig. 6. Thereby, the body 40 is rotatably supported by the bearing member 6 via the enlarged diameter portion 41 and the extended portion 42.

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

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

Further, as shown in fig. 1 and 4, the extension 42 also has an inner protrusion 422 that protrudes radially inward therealong. Specifically, the inner protrusion 422 protrudes inward from the rear peripheral edge portion of the extension 42 along the entire circumference of the extension 42. The diameter-enlarged portion 41 is positioned by hooking the protrusion 411 to the inner protrusion 422 from the side where the output shaft 13 is located (i.e., from the front of the extension portion 42). This makes it easier to regulate the movement of the diameter-enlarged portion 41 relative to the extended portion 42 away from the output shaft 13 (i.e., the rearward movement of the diameter-enlarged 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 disposed closer to the output shaft 13 than the reduction mechanism 5 along the axial direction A1 of the drive shaft 4. In the present embodiment, the bearing member 6 is configured as a bearing C1. As shown in fig. 1, 4, and B of fig. 6, the bearing member 6 includes an inner race 61, an outer race 62, and a plurality of rolling elements (balls) 63 held between the inner race 61 and the outer race 62. Note that in the example shown in B of fig. 1, 4, and 6, illustration of a retainer for retaining the plurality of rolling elements 63 between the inner race 61 and the outer race 62 is omitted.

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

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 is slightly reduced in the positive direction of the X-axis. When the body 40 of the drive shaft 4 is inserted into the spring 12, the spring 12 is disposed between the hammer 11 and the enlarged diameter portion 41 of the drive shaft 4.

As shown in fig. 1, the impact mechanism IM1 further includes a plurality of steel balls 18 (only two of which are shown in fig. 1) and a ring member 19, the steel balls 18 and the ring member 19 all being sandwiched between the hammer 11 and the spring 12. The hammer body 110 has a recess 113 on an X-axis positive-side end surface (i.e., on a rear end surface) to accommodate an X-axis negative-side end portion of the spring 12 (see fig. 1). The recess 113 is a circular ring-shaped recess recessed in the negative X-axis direction when viewed from the positive X-axis side. The plurality of steel balls 18 are disposed in the annular recess 113 along the circumferential direction of the annular recess 113. The ring member 19 is also disposed in the recess 113 so as to cover the plurality of steel balls 18 from behind the steel balls 18. The end of the spring 12 on the X-axis negative side is housed 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 axial direction A1 of the drive shaft 4.

The housing 15 accommodates the drive shaft 4, the reduction mechanism 5, the bearing member 6, the hammer 11, the spring 12, the output shaft 13, the two steel balls 16, and the like. The case 15 has substantially the same shape as the end portion of the cylinder 21 of the housing 2 on the X-axis negative side (i.e., the front end portion of the cylinder 21). In a state where there is almost no gap left between the housing 15 and the cylinder 21, the housing 15 is formed in a size slightly smaller than the front end portion of the cylinder 21 so that the housing 15 is fitted into the front end portion of the cylinder 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 an 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 in the X-axis direction thereof. The cover 15A is formed such that the diameter thereof gradually decreases from the middle in the X-axis direction toward the first opening 151, so that the shorter the distance to obtain the first opening 151, the smaller the diameter of the cover 15A. The aperture area of the first opening 151 is smaller than the aperture area of the second opening 152.

The cover 15A houses the hammer 11 so as to completely surround the hammer 11. The cover 15A also houses 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 also houses the output shaft 13 so as to surround the output shaft 13 in a state where a part of the output shaft 13 (i.e., 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 mount base 15B as a whole has substantially a cylindrical shape that is flat in the X-axis direction. One end of the mounting base 15B on the X-axis negative side is open. The bottom 153 (see fig. 1) of the mounting base 15B has a shaft hole 154, and the shaft hole 154 penetrates the bottom 153 in the X-axis direction. The rotating shaft 310 of the motor 31 is arranged with its tip end portion protruding from the bottom 153 toward the X-axis negative side through-shaft hole 154.

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

The first housing portion H1 is configured to house the bearing member 6. The second housing portion H2 is configured to house the speed reduction mechanism 5. The first housing portion H1 is a space region defined inside the mounting base portion 15B closer to the opening of the mounting base portion 15B. The second receiving portion H2 is a space region defined inside the mounting base portion 15B closer to the bottom 153. That is, the first housing portion H1, the second housing portion H2, and the bottom portion 153 are arranged in parallel in the X-axis direction in order.

The attachment base portion 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 mount base 15B. That is, the ring gear 51 is fixed to the mount base 15B.

The mounting base 15B also holds the bearing member 6 in the first housing portion H1. The bearing member 6 is disposed such that an end portion thereof on the X-axis negative side slightly protrudes 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 (i.e., the rear opening) is stepped down 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 with respect to the first recess R1.

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

As shown in fig. 1, the cover 15A and the attachment 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 indicated by the imaginary line Y1 (dash-dot line) and the hollow arrow in fig. 1, the bearing member 6 is disposed closer to the output shaft 13 than the reduction mechanism 5 (i.e., disposed in front of the reduction mechanism 5; in other words, on the X-axis negative side with respect to the reduction mechanism 5). Thus, it is not necessary 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 (i.e., behind the reduction mechanism 5; in other words, on the X-axis positive side with respect to the reduction mechanism 5). Further, this makes it easier to arrange the bearing member 6 at the same position as the spring 12 in the axial direction A1. This contributes to a reduction in the size of the tool in the axial direction A1 of the drive shaft 4.

In particular, when work needs to be performed above a ceiling, or when a built-in kitchen, a toilet, or a modular bathroom needs to be installed, for example, the work space tends to be relatively narrow. Thus, in an installer who often has to perform a work of fastening a screw using an impact rotation tool in such a narrow working space, there is a significantly increased demand for reducing the size of the tool in the axial direction of the drive shaft. The impact rotation tool 1 according to the present embodiment employs the above-described configuration and structure for the bearing member 6, thereby reducing the size of the tool, and greatly contributing to meeting such a demand.

Further, according to the present embodiment, the bearing member 6 rotatably supports the drive shaft 4 with at least a portion of the spring 12 arranged inside the bearing member 6. That is, the bearing member 6 is disposed outside the spring 12 so as to surround the spring 12. Thereby, arranging the bearing member 6 in the space around the spring 12, which is generally intended as an unused space in the drive block 10, enables the space around the spring 12 to be effectively utilized, thereby making it easier to reduce the size of the tool in the axial direction A1. In addition, according to the present embodiment, the bearing member 6 is disposed between the hammer 11 and the speed reduction mechanism 5 along the axial direction A1 of the drive shaft 4, whereby it is possible to make more effective use of the space around the spring 12, thereby making it easier to reduce the size of the tool along the axial direction A1.

In addition, the drive shaft 4 includes the body 40, the diameter-enlarged portion 41, and the extended portion 42, thereby making it easier to achieve a configuration in which the bearing member 6 is disposed closer to the output shaft 13 than the reduction mechanism 5.

In particular, according to the present embodiment, the extension 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 be smoothly slid (moved with thrust) relative to the body 40 by subjecting the surface of the body 40 to a surface treatment (such as a polishing treatment). If the extension 42 and the body 40 are formed continuously and integrally with each other, the extension 42 will hinder the surface treatment performed 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.

Further, 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 extending portion 42 includes an inner protrusion 422, and the diameter-enlarged portion 41 is positioned by hooking the flange-shaped protrusion 411 to the inner protrusion 422 from the front of the extending portion 42.

In short, two portions of the drive shaft 4, that is, the extended portion 42 and the enlarged diameter portion 41 formed continuously and integrally with the body 40, may be coupled to each other in sequence in the same direction (in the rearward direction) with respect to the bearing member 6. This enables the assembly operation to be completed more efficiently during the manufacturing process.

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

(3) Modification example

Note that the above-described embodiments are merely 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 choices 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 embodiments will sometimes be referred to as "basic examples" hereinafter. Note that each modification to be described below can be employed in appropriate combination with the basic example or any other modification.

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 merely an example and should not be construed as a limitation. Alternatively, the body 40 and the enlarged diameter portion 41 may be provided separately from each other. For example, the diameter-enlarged portion 41 and the extended portion 42 may be formed continuously and integrally with each other, but provided separately from the body 40. Still alternatively, the body 40, the enlarged diameter portion 41, and the extended portion 42 may all be formed continuously and integrally with each other.

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

Also, in the above-described basic example, the inner projection 422 of the extended portion 42 is formed along the entire circumference of the peripheral portion of the extended portion 42. However, this is merely an example and should not be construed as a limitation. Alternatively, the plurality of inner protrusions 422 may be intermittently formed along the circumferential direction of the circumferential edge portion.

Similarly, in the basic example described above, the protrusion 411 of the enlarged diameter portion 41 is formed along the entire periphery of the peripheral edge portion of the enlarged diameter portion 41. However, this is merely an example and should not be construed as a limitation. Alternatively, the plurality of protrusions 411 may be intermittently formed along the circumferential direction of the peripheral portion.

In the above basic example, the impact rotary tool 1 is an impact screwdriver as an example. However, the impact rotary tool 1 need not be an impact screwdriver, but may be, for example, an impact wrench.

(4) Summary of the invention

As can be seen from the foregoing description, the impact rotation tool (1) according to the first aspect includes a drive shaft (4), a speed 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 (rotational 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 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 disposed closer to the output shaft (13) than the speed reduction mechanism (5) in the axial direction (A1) of the drive shaft (4). According to the first aspect, the bearing member (6) is disposed closer to the output shaft (13) than the speed reduction mechanism (5), thereby contributing to a reduction in the size of the tool in the axial direction (A1) of the drive shaft (4).

In an impact rotation tool (1) according to a second aspect implementable in combination with the first aspect, the bearing member (6) rotatably supports the drive shaft (4) with at least a portion of the spring (12) disposed inside the bearing member (6). The second aspect makes it easier to reduce the size of the tool.

In an impact rotary tool (1) according to a third aspect implementable in combination with the first or second aspect, a bearing member (6) is disposed between the hammer (11) and the speed reduction mechanism (5) along the axial direction (A1) of the drive shaft (4). The third aspect makes it easier to reduce the size of the tool.

In an impact rotation tool (1) according to a fourth aspect that can be implemented in combination with any one of the first to third aspects, the drive shaft (4) includes a body (40) that supports the hammer (11) to be rotatable, an enlarged diameter portion (41), and an annular extension portion (42). The enlarged diameter portion (41) projects 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 extending portion (42) extends from the edge of the diameter-expanded 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 achieve a configuration in which the bearing member (6) is disposed closer to the output shaft (13) than the reduction mechanism (5).

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

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

In the impact rotary tool (1) according to a seventh aspect that may be implemented in combination with any one of the fourth to sixth aspects, the bearing member (6) is configured as a bearing (C1). The extension (42) is disposed 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 disposed closer to the output shaft (13) than the reduction mechanism (5).

In an impact rotation tool (1) according to an eighth aspect that may be implemented in combination with the seventh aspect, the extension (42) includes an outer protrusion (421) that protrudes outward in a radial direction of the extension (42). The extension portion (42) is positioned by hooking an outer protrusion (421) of the extension portion (42) onto an end surface (610) of the inner ring (61) facing the output shaft (13) from the side where the output shaft (13) is located. The eighth aspect makes it easier to regulate the movement of the extension (42) away from the output shaft (13) relative to the bearing member (6).

In an impact rotation tool (1) according to a ninth aspect implementable in combination with any one of the fourth to eighth aspects, the extended portion (42) is provided separately from the enlarged diameter portion (41). The extension (42) includes an inner protrusion (422) protruding radially inward of the extension (42). The diameter-expanded portion (41) includes a protruding portion (411) that protrudes outward in the radial direction of the diameter-expanded portion (41). The diameter-expanding section (41) is positioned by hooking the protrusion (411) of the diameter-expanding section (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 diameter-enlarged 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 rotation tool (1), but may be omitted as appropriate.

Description of the reference numerals

1. Impact rotary tool

4. Drive shaft

40. Body

41. Expanding part

411. Protrusion part

42. Extension part

421. External protrusion

422. Inner protrusion

5. Speed reducing mechanism

6. Bearing component

61. Inner ring

610. End face

11. Hammer

12. Spring

13. Output shaft

31. Motor with a stator and a rotor

310. Rotating shaft

A1 Axial direction

B1 End tool

C1 Supporting member

Claims (9)

1. An impact rotary tool comprising:

a drive shaft;

a speed reduction mechanism configured to transmit a rotational force of a shaft of a motor to the drive shaft;

an output shaft configured to receive the rotational force from the drive shaft and transmit the rotational force to a tip tool;

a hammer supported by the drive shaft to be rotatable and configured to strike the output shaft;

a spring that urges the hammer toward the output shaft; and

a bearing member rotatably supporting the drive shaft,

the bearing member is disposed closer to the output shaft than the reduction mechanism in the axial direction of the drive shaft.

2. The impact rotation tool of claim 1,

the bearing member rotatably supports the drive shaft in a state where at least a portion of the spring is arranged inside the bearing member.

3. The impact rotation tool of claim 1 or 2,

the bearing member is disposed between the hammer and the speed reduction mechanism along an axial direction of the drive shaft.

4. The impact rotation tool according to any one of claims 1 to 3,

the drive shaft includes:

a body supporting the hammer to be rotatable;

an enlarged diameter portion projecting radially outwardly 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 from an edge portion of the enlarged diameter portion toward the hammer, and

the bearing member is in contact with the extension portion to rotatably support the drive shaft.

5. The impact rotation tool of claim 4,

the diameter-expanding portion is provided continuously and integrally with the body.

6. The impact rotation tool of claim 4 or 5,

the extension is provided separately from at least the body.

7. The impact rotation tool according to any one of claims 4 to 6,

the bearing member is configured as a support member,

the extension is disposed inside the inner ring of the bearing and supported by the bearing to rotate together with the inner ring.

8. The impact rotation tool of claim 7,

the extension includes an outer protrusion protruding outward in a radial direction of the extension, and

the extension portion is positioned by hooking an outer protrusion of the extension portion from a side where the output shaft is located to an end surface of the inner ring facing the output shaft.

9. The impact rotation tool according to any one of claims 4 to 8,

the extension portion is provided separately from the diameter-expanded portion,

the extension includes an inner protrusion protruding inward in a radial direction of the extension,

the diameter-expanded portion includes a projection portion projecting outward in a radial direction of the diameter-expanded portion, an

The diameter expanding portion is positioned by hooking the protrusion portion to the inner protrusion from a side where the output shaft is located.

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