Impact rotary tool

Abstract

The purpose of the present disclosure is to reduce the tool size in the axis direction of the drive shaft. The impact rotary tool (1) 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 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 end tool (B1). The hammer (11) is rotatably supported by the drive shaft (4) and strikes the output shaft (13). The spring (12) applies a force to the hammer (11) toward the output shaft (13) side. The bearing member (6) rotatably supports the drive shaft (4). The bearing member (6) is located on the output shaft (13) side of the speed reduction mechanism (5) in the axis direction (A1) of the drive shaft (4).

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to an impact rotary tool, and more particularly to an impact rotary tool for generating impact torque. BACKGROUND

[0002] 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 a motor via a speed reducer, an anvil, a hammer for striking the anvil, and a hammer spring for applying force to the hammer toward the anvil. A rear end of a shaft portion of the drive shaft is held by a support fixed in a housing that houses the speed reducer, and a front end of the support is held in a rotatable manner by a rear hole provided through the anvil.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENT

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-172732 SUMMARY

[0006] There is an increasing demand for further reducing the size of an impact rotary tool. In addition to this, there is a rising demand for reducing the size of the tool in the axial direction along its drive shaft.

[0007] Therefore, in view of the above background, an object of the present disclosure is to provide an impact rotary tool that contributes to reducing the size of the tool in the axial direction along its drive shaft.

[0008] 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 a rotational force of a shaft of a motor to the drive shaft. The output shaft receives a rotational force from the drive shaft and transmits the rotational force to a tip tool. The hammer is rotatably supported by the drive shaft and strikes the output shaft. The spring applies force to the hammer toward the output shaft. The bearing member rotatably supports the drive shaft. The bearing member is arranged closer to the output shaft than the speed reduction mechanism in the axial direction of the drive shaft. BRIEF DESCRIPTION OF DRAWINGS

[0009] [ Figure 1 ] Figure 1 is a cross-sectional view of main portions of an impact rotary tool according to an exemplary embodiment.

[0010] [ Figure 2 ] Figure 2 is an appearance view showing an impact rotary tool.

[0011] [ Figure 3 ] Figure 3is a partial cross-sectional view showing the main part of the impact rotary tool.

[0012] [ Figure 4 ] Figure 4 is an exploded perspective view showing the drive shaft, the enlarged diameter portion, the extension portion, and the bearing member of the impact rotary tool.

[0013] [ Figure 5 ] Figure 5 is a perspective view showing the drive shaft and the enlarged diameter portion of the impact rotary tool.

[0014] [ Figure 6 ] Figure 6 A of FIG. 1 is a perspective view showing the main part of the impact rotary tool as viewed obliquely from the front. Figure 6 B of FIG. 1 is a perspective view showing the main part of the impact rotary tool as viewed obliquely from the back. DETAILED DESCRIPTION

[0015] (1) SUMMARY

[0016] The drawings referred to in the following description of the embodiments are schematic representations. Consequently, the ratios of the dimensions (including the thicknesses) of the various constituent elements shown in the drawings do not always reflect the actual dimensional ratios thereof.

[0017] As shown in FIG. 1, the impact rotary tool 1 according to the example 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. Figure 1

[0018] The speed reduction mechanism 5 transmits the rotational force of the shaft (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 rotational speed and the torque of the rotational shaft 310 of the motor 31 into the rotational speed and the torque required for the operation of the screwdriver.

[0019] 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 (i.e., the anvil) of the output shaft 13. The spring 12 exerts a force on 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 arranged closer to the output shaft 13 than the speed reduction mechanism 5 along the axial direction Al of the drive shaft 4. Figure 1

[0020] ​​According to this configuration, the bearing member 6 is arranged closer to the output shaft 13 than the reduction mechanism 5. Therefore, there is no need to reserve space for arranging the bearing member 6 on the opposite side of the output shaft 13 relative to the reduction mechanism 5. This helps to reduce the size of the tool along the axial direction A1 of the drive shaft 4.

[0021] (2) Details

[0022] (2.1) Overall Structure

[0023] Next, the overall structure of the impact rotation tool 1 according to this embodiment will be described in detail.

[0024] In the following description, exemplary embodiments will be described, wherein, as Figures 1 to 4 The diagram defines three axes (i.e., the X-axis, Y-axis, and Z-axis) that intersect each other at right angles. Specifically, in the exemplary embodiment described below, the axis A1 of the drive shaft 4 of the impact rotary tool 1 (refer to...) Figure 1 The axis that aligns with the orientation of the housing 2 (described later) of the impact rotary tool 1 is defined herein as the "X-axis". Additionally, the axis that aligns with the orientation of the cylinder 21 and base 23 of the housing 2 (described later) of the impact rotary tool 1 is defined herein as the "Y-axis". In the following description, the direction aligned with the X-axis will be simply referred to as the "front-back direction". The negative side of the X-axis will be simply referred to as the "front", and the positive side of the X-axis will be simply referred to as the "rear". Furthermore, the direction aligned with the Y-axis will be simply referred to herein as the "up-down direction", the positive side of the Y-axis will be simply referred to as the "above", and the negative side of the Y-axis will be simply referred to as the "below".

[0025] Note that the X, Y, and Z axes are imaginary axes, and the arrows indicating these axes in the accompanying drawings are shown there for illustrative purposes only and are not physical. It should also be noted that these directions do not preclude the direction in which the impact rotation tool 1 should be used.

[0026] The impact rotary tool 1 is a portable power tool that can be held by a user with one hand. The impact rotary tool 1 includes a motor block 3 (see reference). Figure 3 ), drive block 10 (transmission mechanism, see reference) Figure 1 and Figure 3 ) and outer casing 2 (refer to Figure 2 The drive block 10 drives the rotating shaft 310 of the motor 31 in the motor block 3 (refer to...). Figure 1 The rotational force is transmitted to the end tool B1. The housing 2 houses the motor block 3 and the drive block 10.

[0027] The impact rotary tool 1 also includes a retaining part 7 (sleeve mounting part, see reference). Figures 1-3) to hold a bit (such as a screwdriver) used as an end tool B1 on the holding portion 7. The end tool B1 is detachably mounted to the holding portion 7. The driving block 10 drives the end tool B1 using a rotational force generated by the motor 31. The driving block 10 according to the present embodiment includes an impact mechanism IM1 (refer to Figure 1 ). Note that the driving block 10 will be described in detail in the following section.

[0028] The impact rotary tool 1 according to the present embodiment can be an impact screwdriver that allows a user to perform a work of fastening a screw B2 (refer to Figure 2 ) with an impact force applied by the impact mechanism IM1.

[0029] A rechargeable battery pack 9 (refer to Figure 2 ) is detachably mounted to the impact rotary tool 1. The impact rotary tool 1 is powered by the battery pack 9. In the present embodiment, the battery pack 9 is not a constituent element of the impact rotary tool 1. However, this is merely an example, and should not be construed as a limitation. Alternatively, the impact rotary tool 1 can 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 battery 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 about a temperature, a battery level, a rated voltage, a rated capacity, and a number of times of charging.

[0030] As shown in Figure 2 , the housing 2 includes a cylinder 21, a grip portion 22, and a base portion 23. The cylinder 21 has a hollow cylindrical shape. The grip portion 22 protrudes from an outer peripheral surface of the cylinder 21 in one direction (downward) coinciding with a radial direction of the cylinder 21. The grip portion 22 is formed in a hollow cylindrical shape long in the one direction. An inner space of the grip portion 22 communicates with an inner space of the cylinder 21. The cylinder 21 is connected to one end (i.e., an upper end) in a length direction of the grip portion 22, and the base portion 23 is connected to the other end (i.e., a lower end) in the length direction of the grip portion 22. The battery pack 9 is detachably mounted to the base portion 23.

[0031] As shown in Figure 2 , the impact rotary tool 1 further includes a switch circuit module 81, an operation member 82, a forward-reverse switching switch 83, and a control circuit module 84.

[0032] The switch circuit module 81 is arranged in the inner space of the grip portion 22. The switch circuit module 81 is electrically connected to the control circuit module 84. The control circuit module 84 is housed in the base portion 23.

[0033] The switch circuit module 81 includes a main switch. The main switch is used to open and close a power supply path for supplying electric power from the battery pack 9 to the motor 31. The operation member 82 is a trigger lever that is operated by a user of the impact rotary tool 1 with one finger. The operation 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.

[0034] When the operation member 82 is pulled to a depth equal to or less than a predetermined value, the switch circuit module 81 closes the main switch, but when the operation member 82 is pulled to a depth greater than the predetermined value, the switch circuit module 81 opens the main switch. This allows the switch circuit module 81 to selectively supply or shut off electric power from the battery pack 9 to the motor 31. Furthermore, when the operation member 82 is pulled to a depth greater than the predetermined value, the switch circuit module 81 also transmits an operation signal corresponding to the depth at which the operation member 82 is pulled 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 rotational shaft 310 of the motor 31.

[0035] Furthermore, the switch circuit module 81 is also connected to a forward-reverse switching switch 83. The forward-reverse switching switch 83 is a direction switch that allows the user to change the rotational direction of the rotational shaft 310 of the motor 31. The forward-reverse switching switch 83 is disposed near the boundary between the barrel 21 and the grip portion 22.

[0036] The control circuit module 84 is connected to the switch circuit 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 electric power from the battery pack 9 to be supplied to the control circuit module 84 via the pair of power terminals. Furthermore, 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 in accordance with the operation signal supplied from the switch circuit module 81. More specifically, the control circuit module 84 controls parameters such as the rotational speed and the rotational direction of the rotational shaft 310 of the motor 31.

[0037] The motor block 3 is housed in the internal space of the barrel 21 of the housing 2 in such a manner as to be located on the positive side of the X axis. The motor block 3 is fixed to the housing 2. The barrel 21 has a plurality of ventilation holes 211, 212 (refer to Figure 2 ) surrounding the motor block 3.

[0038] As shown in Figure 3 , the motor block 3 includes the motor 31, the fan 32, and the drive circuit module 33.

[0039] The motor 31 is a brushless motor. The motor 31 includes a motor body 311 (refer to Figure 3) and a rotation shaft 310 (refer to Figure 1 ) held rotatable by the motor body 311.

[0040] 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 turn together with the rotation shaft 310 of the motor 31.

[0041] The drive circuit module 33 is controlled by the control circuit 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 package portion that packages the circuit board and the plurality of transistors together.

[0042] The rotation shaft 310 of the motor 31 is supported by the drive block 10. A rotational force (driving force) generated by a rotor of the motor body 311 is transmitted from the rotation shaft 310 to the drive block 10.

[0043] (2.2) Drive Block

[0044] Next, the drive block 10 will be described in detail. The drive block 10 is housed in the inner space of the cylinder 21 of the housing 2 in a manner so as to be located on the negative side of the X axis with respect to the motor block 3.

[0045] As shown in Figure 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 tip side bearing member 17.

[0046] The output shaft 13 is configured to receive a rotational force of the drive shaft 4 and transmit the rotational force to the tip tool B1. The output shaft 13 is arranged 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 a manner such that a central axis thereof substantially coincides with a central axis of the drive shaft 4. As shown in Figure 1 , the output shaft 13 is formed so that the mandrel 13A and the impact receiving portion 14 (anvil) are continuous and integral with each other. In the impact rotary tool 1, the tip of the mandrel 13A doubles as a part of the holding portion 7, thereby allowing the tip tool B1 to be fixed to the tip of the mandrel 13A.

[0047] The tip side bearing member 17 is configured as a bearing. The mandrel 13A is rotatably supported by the tip side bearing member 17. An outer peripheral surface of the mandrel 13A has a groove in which an O-ring G1 is fitted. The mandrel 13A is stably held by an inner ring of the tip side bearing member 17 via the O-ring G1. Further, the mandrel 13A is coupled to the drive shaft 4. Thereby, the mandrel 13A rotates together with the drive shaft 4. Note that the drive shaft 4 is rotatably supported by the bearing member 6 (to be described later).

[0048] The rotating shaft 310 of motor 31 is connected to the reduction mechanism 5. The rotational force of the rotating shaft 310 of 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, hammer 11, spring 12, output shaft 13, and two steel balls 16. The rotational force of the rotating shaft 310 of motor 31 is transmitted to the spindle 13A of output shaft 13 by the impact mechanism IM1.

[0049] The reduction mechanism 5 transmits the rotational force of the rotating shaft 310 of the motor 31 to the drive shaft 4. Specifically, the reduction mechanism 5 is a planetary gear mechanism used to convert the rotational speed and torque of the rotating 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 planetary gears 53. Figure 1 As shown, the sun gear 52 is continuous with and integral with the rotating shaft 310 of the motor 31. Three planetary gears 53 mesh with the sun gear 52 on its outer side. Figure 6 As shown in B, the gear ring 51 meshes with and supports the three planetary gears 53.

[0050] Hammer 11 is rotatable and supported by drive shaft 4, striking impact receiving part 14 of output shaft 13. Hammer 11 includes a generally cylindrical hammer body 110, which is flattened overall in the X-axis direction. Hammer body 110 has a through hole 111 through which drive shaft 4 passes in the X-axis direction. Hammer body 110 has a groove 112 on the inner circumferential surface of through hole 111. Two steel balls 16 are sandwiched between groove 112 and groove 43, which is provided on the outer circumferential surface of body 40 of drive shaft 4.

[0051] Grooves 112 and 43, together with the two steel balls 16, form a cam mechanism. When the two steel balls 16 roll within groove 43, the hammer 11 can move not only 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 towards the spindle 13A of the output shaft 13 (i.e., forward movement) or away from the spindle 13A of the output shaft 13 (i.e., backward movement) along the axial direction A1 of the drive shaft 4, depending on its rotation angle.

[0052] Note that lubricant is applied, for example, to the reduction gear 5. The lubricant is used to reduce friction and wear, for example, in the drive block 10. The lubricant is electrically insulating. For example, the lubricant can be a synthetic hydrocarbon oil grease.

[0053] like Figure 1 , Figure 4 , Figure 6 A and Figure 6 As shown in B, the drive shaft 4 includes a body 40, an expanded diameter portion 41, and an extension portion 42.

[0054] 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. The body 40 can be a metal portion, for example. The body 40 has an insertion recess 400 provided to penetrate 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 Figure 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. Further, the body 40 has a groove 43 to allow the two steel balls 16 to roll therein as described above.

[0055] 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 coincides with the central axis of the body 40. The enlarged diameter portion 41 can be a metal portion, for example. In addition, in the present embodiment, the enlarged diameter portion 41 can be formed continuously and integrally with the body 40, for example. Further, the enlarged diameter portion 41 has a protrusion portion 411 (refer to Figure 1 and Figure 4 ) protruding radially outward therefrom. The protrusion portion 411 can be a flange-like portion.

[0056] Specifically, the enlarged diameter portion 41 includes a first portion 41A, a second portion 41B, and three columns 41C.

[0057] The first portion 41A is in a plate-like shape when viewed in the X-axis direction. A peripheral edge portion 415 (refer to Figure 5 ) of the first portion 41A protrudes in the X-axis negative direction along the entire periphery thereof. The first portion 41A is a cup-like portion as a whole. In other words, the first portion 41A has a positioning recess 410 (refer to Figure 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 protrusion portion 411 described above is provided to the first portion 41A. That is, the peripheral edge portion 415 of the first portion 41A protruding in the X-axis negative direction along the entire periphery thereof has a flange shape protruding radially outward. The flange-like protrusion portion is the protrusion portion 411.

[0058] The first portion 41A is formed continuously and integrally with the rear end portion of the body 40 and protrudes radially outward from the rear end portion of the body 40. A circular ring-shaped sheet member T1 (refer to Figure 1 and Figure 6 is placed at the bottom of the positioning recess 410.A). The spring 12 is housed in the positioning recess 410 at the end on the positive side of the X axis in contact with the front surface of the sheet member T1. That is, the spring 12 exerts a force on the bottom of the first portion 41A via the sheet member T1. This allows the end of the spring 12 on the positive side of the X axis to be stably positioned relative to the drive shaft 4.

[0059] As shown in Figure 4 and Figure 5 , the first portion 41A has three shaft insertion holes 412 provided through the bottom thereof. The front ends of the three shafts 530 of the three planetary gears 53 (refer to Figure 6 B) 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 negative side of the X axis. The sheet member T1 can be made of felt, for example. The sheet member T1 captures lubricant applied to the reduction mechanism 5 and substantially prevents the lubricant from flowing to the outside of the reduction mechanism 5. Furthermore, the sheet member T1 reduces the likelihood that the shafts 530 will come into contact with and scratch the surrounding portions when the planetary gears 53 rotate.

[0060] Furthermore, as shown in Figure 1 , at the bottom of the positioning recess 410, a circular ring-shaped elastic member S1 and a circular ring-shaped sheet member S2 that covers the front surface of the elastic member S1 are disposed inside the sheet member T1. If the hammer 11 moves in the positive direction of the X axis by overcoming the elastic force exerted by the spring 12, the rear end of the hammer 11 will come into contact with the sheet member S2, thereby allowing the elastic member S1 to absorb the impact.

[0061] The second portion 41B is a circular plate-shaped portion whose thickness is aligned with the X axis direction. The second portion 41B is arranged so that the front surface thereof faces the rear surface of the first portion 41A. In a state in which a predetermined distance is left between the first portion 41A and the second portion 41B, the three columns 41C are portions that couple the first portion 41A and the second portion 41B to each other. That is, the first portion 41A is formed continuously and integrally with the second portion 41B via the three columns 41C. The three planetary gears 53 are housed in a gap SP1 (refer to Figure 5 ) surrounded by the first portion 41A and the second portion 41B. Note that the three planetary gears 53 are housed in the gap SP1 with their outer peripheral portions partially protruding from the gap SP1 to allow the three planetary gears 53 to mesh with the ring gear 51. The gap SP1 is roughly divided into three spaces by the three columns 41C, and the three planetary gears 53 are respectively housed in the three spaces.

[0062] The second portion 41B has three shaft insertion holes 413 (refer to Figure 5The three shafts 530 of the three planetary gears 53 are respectively inserted into the three shaft insertion holes 412 of the first part 41A in the X-axis direction, and the corresponding rear ends of the three shafts 530 of the three planetary gears 53 are inserted into the three shaft insertion holes 413.

[0063] 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 supported by the enlarged diameter portion 41 to be rotatable.

[0064] like Figure 5 As shown, the second part 41B has an insertion hole 414 as its center hole. Additionally, the body 40, continuously and integrally formed with the first part 41A, has an undercut recess 401, which is configured to penetrate the central region of the rear end face of the body 40 in a manner facing the insertion hole 414, as shown. Figure 5 As shown. The rotating shaft 310 of the motor 31 is inserted into and passes through the insertion hole 414. Furthermore, in the state of meshing with the three planetary gears 53, the front end of the sun gear 52, which is continuously and integrally formed with the rotating shaft 310, is inserted into the undercut recess 401 without contacting the inner circumferential surface of the undercut recess 401.

[0065] Note that an annular plate member (e.g., made of felt) covering the three shaft insertion holes 413 from the positive side of the X-axis is also arranged on the rear surface of the second part 41B. The annular plate member and the plate member T1 essentially prevent lubricant from flowing out of the reduction gear 5. In addition, when the planetary gear 53 rotates, the annular plate member also reduces the possibility of the shaft 530 contacting and scuffing its surrounding parts.

[0066] 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 can be a metal portion. The extension 42 is at least separate from the body 40. In this embodiment, the expansion portion 41 is formed continuously and integrally with the body 40. Thus, the extension 42 is separate from both the body 40 and the expansion portion 41. The body 40 and the expansion portion 41 are assembled and fixed into the extension 42 from the negative side of the X-axis (i.e., from the front of the extension 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. At the same time, the second part 41B, the three pillars 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 gear ring 51. As a result, the extension 42 extends from the edge of the expansion portion 41 toward the hammer 11, as... Figure 1 As shown. The central axis of the extension 42 is aligned with the central axis of the main body 40.

[0067] The extension 42 is assembled and fixed into the bearing member 6. In this embodiment, the bearing member 6 is configured as a support member C1, which will be described later. Thus, the extension 42 is arranged inside the inner ring 61 of the support member C1 and is supported by the support member C1 to rotate together with the inner ring 61, as shown below. Figure 1 , Figure 6 A and Figure 6 As shown in B. Thus, the body 40 is rotatably supported by the bearing member 6 via the enlarged diameter portion 41 and the extension portion 42.

[0068] When the sun gear 52, which is continuous with and integral with the rotating shaft 310 of the motor 31, rotates, the three planetary gears 53 also rotate within the gear ring 51 along the circumference of the gear ring 51. As a result, the main body 40, the expanded diameter portion 41, and the extension portion 42 rotate together with each other.

[0069] like Figure 1 and Figure 4 As shown, the extension 42 has an outwardly projecting protrusion 421 protruding radially outward. The outwardly projecting protrusion 421 is a flange-like portion. Specifically, the outwardly projecting protrusion 421 protrudes outward from the front peripheral edge of the extension 42 along its entire circumference. Furthermore, the extension 42 is positioned by hooking the outwardly projecting protrusion 421 from the side where the output shaft 13 is located (i.e., from the front of the extension 42) onto the end face 610 of the inner ring 61 facing the output shaft 13. This makes it easier to control 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).

[0070] In addition, such as Figure 1 and Figure 4 As shown, the extension 42 also has an inner protrusion 422 that projects radially inward. Specifically, the inner protrusion 422 projects inward from the rear peripheral edge of the extension 42 along its entire circumference. The enlarged diameter portion 41 is positioned by hooking the protrusion 411 onto the inner protrusion 422 from the side where the output shaft 13 is located (i.e., from the front of the extension 42). This makes it easier to control the movement of the enlarged diameter portion 41 relative to the extension 42 away from the output shaft 13 (i.e., the rearward movement of the enlarged diameter portion 41).

[0071] The bearing member 6 rotatably supports the drive shaft 4. Specifically, the bearing member 6 supports the drive shaft 4, which is rotatably in contact with the extension 42. In this embodiment, the bearing member 6 is arranged such that it is closer to the output shaft 13 than the reduction gear 5 along the axial direction A1 of the drive shaft 4. In this embodiment, the bearing member 6 is configured as a support member C1. Figure 1 , Figure 4 and Figure 6 As shown in Figure B, the bearing component 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 Figure 1 ,Figure 4 and Figure 6 In the example shown in B of the above-described embodiment, the illustration of the retainer for holding the plurality of rolling elements 63 between the inner ring 61 and the outer ring 62 is omitted.

[0072] The bearing member 6 rotatably supports the drive shaft 4 in a state in which at least a part of the spring 12 (for example, the end portion of the spring 12 on the positive side of the X axis in this example) is arranged inside the bearing member 6. In other words, the bearing member 6 is arranged on the outer side of the spring 12 to surround the spring 12 with the inner ring 61 of the bearing member 6.

[0073] Further, the bearing member 6 is arranged between the hammer 11 and the speed reduction mechanism 5 along the axial direction Al of the drive shaft 4.

[0074] The spring 12 exerts a force on the hammer 11 toward the output shaft 13. Specifically, the spring 12 is configured as a conical coil spring whose diameter slightly decreases in the positive direction of the X axis. In a case where the body 40 of the drive shaft 4 is inserted and passes through the spring 12, the spring 12 is arranged between the hammer 11 and the enlarged diameter portion 41 of the drive shaft 4.

[0075] As shown in Figure 1 , the impact mechanism IM1 further includes a plurality of steel balls 18 (only two of which are shown in Figure 1 ) and a ring member 19, all of which are sandwiched between the hammer 11 and the spring 12. The hammer body 110 has a recess 113 on the end face on the positive side of the X axis (i.e., on the rear end face) to accommodate the end portion on the negative side of the X axis of the spring 12 (refer to Figure 1 ). The recess 113 is a circular ring-shaped recess that is recessed in the negative direction of the X axis when viewed from the positive side of the X axis. The plurality of steel balls 18 are arranged within the circular ring-shaped recess 113 along the circumferential direction of the circular ring-shaped recess 113. Further, the ring member 19 is also arranged within the recess 113 in such a manner as to cover the plurality of steel balls 18 from the rear side of the steel balls 18. The end portion on the negative side of the X axis of the spring 12 is accommodated in the recess 113 while exerting a force forward on the ring member 19. This makes the hammer 11 rotatable with respect to the spring 12. The hammer 11 receives the force from the spring 12 in the direction along the axial direction Al of the drive shaft 4 toward the impact receiving portion 14 of the output shaft 13.

[0076] The housing 15 accommodates the drive shaft 4, the speed reduction mechanism 5, the bearing member 6, the hammer 11, the spring 12, the output shaft 13, and the two steel balls 16, etc. therein. The housing 15 has substantially the same shape as the end portion on the negative side of the X axis of the cylinder body 21 of the outer case 2 (i.e., the front end portion of the cylinder body 21). The housing 15 is formed to be slightly smaller in size than the front end portion of the cylinder body 21 in a state in which there is almost no gap left between the housing 15 and the cylinder body 21, so that the housing 15 fits into the front end portion of the cylinder body 21.

[0077] As shown in Figure 1As shown, the housing 15 includes a cover 15A and a mounting base 15B.

[0078] For example, the cap 15A can be made of an alloy. The cap 15A has a cylindrical shape with both ends open in the X-axis direction. For example... Figure 1 As shown, 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. The cover 15A is formed such that its diameter gradually decreases from the middle in the X-axis direction toward the first opening 151, such 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.

[0079] Cover 15A accommodates hammer 11 in a manner that completely surrounds hammer 11. In addition, cover 15A also accommodates drive shaft 4 and spring 12 in a manner that completely surrounds drive shaft 4 and spring 12. Furthermore, when a portion of output shaft 13 (i.e., its end on the negative side of the X-axis) protrudes from the first opening 151, cover 15A also accommodates output shaft 13 in a manner that surrounds output shaft 13.

[0080] Mounting base 15B is electrically insulating. For example, mounting base 15B can be made of synthetic resin. Mounting base 15B as a whole is substantially cylindrical in shape, flattened in the X-axis direction. One end of mounting base 15B on the negative X-axis side is open. The bottom 153 of mounting base 15B (see reference) Figure 1 The motor 31 has a shaft hole 154 that passes through the bottom 153 along the X-axis. The rotating shaft 310 of the motor 31 is arranged such that its end protrudes from the bottom 153 toward the negative side of the X-axis through the shaft hole 154.

[0081] The mounting base 15B has an inner circumferential surface whose inner diameter decreases in a stepped manner towards the bottom 153. This stepped inner circumferential surface defines a first receiving portion H1 and a second receiving portion H2, wherein the inner diameter of the second receiving portion H2 is smaller than the inner diameter of the first receiving portion H1. In other words, the mounting base 15B internally includes the first receiving portion H1 and the second receiving portion H2.

[0082] The first receiving portion H1 is configured to house the bearing member 6. The second receiving portion H2 is configured to house the reduction mechanism 5. The first receiving portion H1 is a spatial region defined inside the mounting base 15B, closer to the opening of the mounting base 15B. The second receiving portion H2 is a spatial region defined inside the mounting base 15B, closer to the bottom 153. That is, the first receiving portion H1, the second receiving portion H2, and the bottom 153 are arranged side by side in the positive X-axis direction.

[0083] Mounting base 15B holds the gear ring 51 of the reduction gear 5 in the second receiving portion H2. For example, the gear ring 51 can be insert-shaped relative to mounting base 15B. That is, the gear ring 51 is fixed to mounting base 15B.

[0084] The mounting base 15B also holds the bearing member 6 in the first housing portion H1. The bearing member 6 is configured such that its end portion on the X-axis negative side slightly protrudes in the X-axis negative direction with respect to the first housing portion H1 (refer to Figure 1 ). The protruding portion of the bearing member 6 is held by the cover 15A.

[0085] Specifically, the cover 15A is formed such that the inner diameter of the inner peripheral surface thereof adjacent to the second opening 152 (i.e., the rear opening) is stepwise reduced 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 the inner peripheral surface thereof adjacent to the second opening 152, the inner diameter of the second recess R2 being 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.

[0086] The cover 15A is assembled to the mounting base 15B by fitting the outer peripheral wall W1 (refer to Figure 1 ) of the mounting 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. The provision of 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 casing 15 through the gap between the outer peripheral wall W1 and the inner peripheral surface of the second recess R2.

[0087] Further, as shown in Figure 1 , the cover 15A and the mounting base 15B hold the bearing member 6 in such a manner as to sandwich the outer ring 62 of the bearing member 6 between the first recess R1 and the first housing portion H1. Thus, the bearing member 6 can be positioned within the casing 15 with good stability.

[0088] (2.3) Advantages

[0089] In the present embodiment, as indicated by the dashed-dotted line Y1 (dashed-dotted line) and the hollow arrow in Figure 1 , the bearing member 6 is arranged closer to the output shaft 13 than the speed reduction mechanism 5 (i.e., arranged in front of the speed reduction mechanism 5; in other words, located on the X-axis negative side with respect to the speed reduction mechanism 5). Thereby, 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 speed reduction mechanism 5 (i.e., behind the speed reduction mechanism 5; in other words, on the X-axis positive side with respect to the speed reduction mechanism 5). Further, this makes it easier to arrange the bearing member 6 at the same position as the spring 12 along the axial direction Al. This contributes to reducing the size of the tool along the axial direction Al of the drive shaft 4.

[0090] 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, among installers who often have to perform work of fastening screws using an impact rotary tool in such a narrow work space, there is a significant increase in 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 described above for the bearing member 6, thereby reducing the size of the tool, greatly contributing to meeting such demand.

[0091] Further, according to the present embodiment, the bearing member 6 rotatably supports the drive shaft 4 with at least a part of the spring 12 arranged inside the bearing member 6. That is, the bearing member 6 is arranged outside the spring 12 in a manner of surrounding the spring 12. Thus, by 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, it is possible to make effective use of the space around the spring 12, thereby making it easier to reduce the size of the tool in the axial direction Al. In addition, according to the present embodiment, the bearing member 6 is arranged between the hammer 11 and the speed reduction mechanism 5 in the axial direction Al 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 size of the tool in the axial direction Al.

[0092] In addition, the drive shaft 4 includes the body 40, the diameter-expanded portion 41, and the extension portion 42, thereby making it easier to achieve such a configuration in which the bearing member 6 is arranged closer to the output shaft 13 than the speed reduction mechanism 5.

[0093] In particular, according to the present embodiment, the extension portion 42 is provided separately from the body 40, thereby achieving the following advantages. Specifically, during the manufacturing process of the impact rotary tool 1, the hammer 11 needs to be smoothly slid (moved by a pushing force) with respect to the body 40 by subjecting the surface of the body 40 to surface treatment such as polishing treatment. If the extension portion 42 and the body 40 are continuously and integrally formed with each other, the extension portion 42 will hinder the surface treatment performed on the body 40. In contrast, separate provision of the extension portion 42 from the body 40, for example, as in the present embodiment, makes it easier to perform the surface treatment on the body 40.

[0094] Further, according to the present embodiment, the extension portion 42 includes a flange-shaped outer protrusion 421, and is positioned by hooking the outer protrusion 421 onto the end face 610 of the inner ring 61 from the front. In addition, the extension portion 42 includes an inner protrusion 422, and the diameter-expanded portion 41 is positioned by hooking the flange-shaped protrusion portion 411 onto the inner protrusion 422 from the front of the extension portion 42.

[0095] Briefly, the two portions of the drive shaft 4, i.e., the extension 42 and the enlarged diameter portion 41 which is continuous and integrally formed with the body 40, can be coupled to each other in sequence with respect to the bearing member 6 in the same direction (in the rearward direction). This makes it possible to more efficiently accomplish the assembly work during the manufacturing process.

[0096] In addition, the two portions of the drive shaft 4, i.e., the extension 42 and the enlarged diameter portion 41 which is continuous and integrally formed with the body 40, are coupled to each other by regulating their rearward movement with respect to the bearing member 6. When the screw fastening work is performed using the impact rotary tool 1, the impact rotary tool 1 receives a load applied in the positive direction of the X axis (i.e., in the rearward direction) from the 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 extension 42, thereby being able to provide a particularly reliable tool.

[0097] (3) Modified Examples

[0098] 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 can be easily modified in various ways without departing from the scope of the present disclosure, in accordance with design choices or any other factors.

[0099] Next, modified examples of the exemplary embodiments will be shown one by one. In the following description, the above-described exemplary embodiments will be sometimes referred to as "basic examples" hereinafter. Note that each of the modified examples to be described below can be adopted in appropriate combination with the basic examples or any other modified examples.

[0100] In the above-described basic examples, the 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 limiting. Alternatively, the body 40 and the enlarged diameter portion 41 can be provided separately from each other. For example, the enlarged diameter portion 41 and the extension 42 can be continuously and integrally formed with each other, but provided separately from the body 40. Also alternatively, the body 40, the enlarged diameter portion 41, and the extension 42 can all be continuously and integrally formed with each other.

[0101] In the above-described basic examples, the outer protrusion 421 of the extension 42 is formed along the entire circumference of the peripheral portion of the extension 42. However, this is merely an example, and should not be construed as limiting. Alternatively, a plurality of outer protrusions 421 can be intermittently formed along the circumferential direction of the peripheral portion.

[0102] Also in the above-described basic examples, the inner protrusion 422 of the extension 42 is formed along the entire circumference of the peripheral portion of the extension 42. However, this is merely an example, and should not be construed as limiting. Alternatively, a plurality of inner protrusions 422 can be intermittently formed along the circumferential direction of the peripheral portion.

[0103] Also, in the basic example described above, the protruding portion 411 of the diameter-expanded portion 41 is formed along the entire circumference of the peripheral portion of the diameter-expanded portion 41. However, this is merely an example, and should not be construed as limiting. Alternatively, a plurality of protruding portions 411 can be intermittently formed along the circumferential direction of the peripheral portion.

[0104] In the basic example described above, the impact rotary tool 1 is an impact screwdriver as an example. However, the impact rotary tool 1 is not necessarily an impact screwdriver, but can be, for example, an impact wrench.

[0105] (4) SUMMARY

[0106] As can be seen from the foregoing description, the impact rotary 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 a rotational force of a shaft (rotational shaft 310) of a motor (31) to the drive shaft (4). The output shaft (13) receives a rotational force from the drive shaft (4) and transmits the rotational force to an end tool (B1). The hammer (11) is rotatably supported by the drive shaft (4) and strikes the output shaft (13). The spring (12) exerts a force on the hammer (11) toward 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 speed reduction mechanism (5) along an axial 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 speed reduction mechanism (5), thereby contributing to reduction in the size of the tool along the axial direction (A1) of the drive shaft (4).

[0107] In the impact rotary tool (1) according to the second aspect which can be implemented in combination with the first aspect, the bearing member (6) rotatably supports the drive shaft (4) in a case where at least a part of the spring (12) is arranged inside the bearing member (6). The second aspect makes it easier to reduce the size of the tool.

[0108] In the impact rotary tool (1) according to the third aspect which can be implemented in combination with the first or second aspect, 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). The third aspect makes it easier to reduce the size of the tool.

[0109] In the impact rotary tool (1) according to the fourth aspect which can be implemented in combination with any one of the first to third aspects, the drive shaft (4) includes a body (40) that rotatably supports the hammer (11), a diameter-enlarged portion (41), and an annular extension portion (42). The diameter-enlarged portion (41) protrudes radially outward from the body (40) and is configured to position the spring (12) between the hammer (11) and the diameter-enlarged portion (41) itself. The extension portion (42) extends from an edge portion of the diameter-enlarged portion (41) toward the hammer (11). The bearing member (6) is in contact with the extension portion (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 arranged closer to the output shaft (13) than the speed reduction mechanism (5).

[0110] In the impact rotary tool (1) according to the fifth aspect which can be implemented in combination with the fourth aspect, the diameter-enlarged portion (41) is provided continuously and integrally with the body (40). The fifth aspect can reduce an increase in the number of required components.

[0111] In the impact rotary tool (1) according to the sixth aspect which can be implemented in combination with the fourth or fifth aspect, the extension portion (42) is provided separately at least from 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 portion (42) is formed continuously and integrally with the body (40).

[0112] 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 bearing (C1). The extension portion (42) is arranged inside an 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 achieve a configuration in which the bearing member (6) is arranged closer to the output shaft (13) than the speed reduction mechanism (5).

[0113] In the impact rotary tool (1) according to the eighth aspect which can be implemented in combination with the seventh aspect, the extension portion (42) includes an outer protrusion (421) that protrudes radially outward along the extension portion (42). The extension portion (42) is positioned by hooking the outer protrusion (421) of the extension portion (42) from a side on which the output shaft (13) is located onto an end surface (610) of the inner ring (61) that faces the output shaft (13). The eighth aspect makes it easier to regulate movement of the extension portion (42) away from the output shaft (13) with respect to the bearing member (6).

[0114] In the impact rotary tool (1) according to the ninth aspect which can be implemented in combination with any one of the fourth to eighth aspects, the extension portion (42) is provided separately from the diameter-enlarged portion (41). The extension portion (42) includes an inner protrusion (422) protruding radially inward along the extension portion (42). The diameter-enlarged portion (41) includes a protrusion portion (411) protruding radially outward along the diameter-enlarged portion (41). The diameter-enlarged portion (41) is positioned by hooking the protrusion portion (411) of the diameter-enlarged portion (41) from the side on which the output shaft (13) is located onto the inner protrusion (422). The ninth aspect makes it easier to regulate the movement of the diameter-enlarged portion (41) away from the output shaft (13) with respect to the extension portion (42).

[0115] Note that the constituent elements according to the second to ninth aspects are not essential constituent elements of the impact rotary tool (1) and can be omitted as appropriate.

[0116] Legend of Reference Numerals

[0117] 1 impact rotary tool

[0118] 4 drive shaft

[0119] 40 body

[0120] 41 diameter-enlarged portion

[0121] 411 protrusion portion

[0122] 42 extension portion

[0123] 421 outer protrusion

[0124] 422 inner protrusion

[0125] 5 speed reduction mechanism

[0126] 6 bearing member

[0127] 61 inner ring

[0128] 610 end surface

[0129] 11 hammer

[0130] 12 spring

[0131] 13 output shaft

[0132] 31 motor

[0133] 310 rotation shaft

[0134] A1 axial direction

[0135] B1 tip tool

[0136] C1 support

Claims

1. An impact rotary tool, comprising: Drive shaft; A reduction mechanism configured to transmit the rotational force of the motor shaft to the drive shaft; An output shaft is configured to receive rotational force from the drive shaft and transmit the rotational force to the end tool; A hammer, which is rotatable and configured to strike the output shaft, is supported by the drive shaft. A spring that exerts a force on the hammer toward the output shaft; as well as A bearing component that rotatably supports the drive shaft. The bearing component is arranged to be closer to the output shaft than the reduction gear along the axial direction of the drive shaft. The drive shaft includes: The body supports the hammer so that it can rotate; An enlarged portion, which protrudes radially outward from the body and is configured to position the spring between the hammer and the enlarged portion itself; and An extension, having a ring shape, extends from the edge of the enlarged diameter portion toward the hammer, and The bearing component contacts the extension to rotatably support the drive shaft. The extension portion is disposed separately from the diameter expansion portion. The extension includes an inwardly projecting protrusion along the radial direction of the extension. The enlarged diameter portion includes a protrusion that projects radially outward along the enlarged diameter portion, and The enlarged diameter portion is positioned by hooking the protrusion from the side where the output shaft is located onto the inner protrusion.

2. The impact rotary tool according to claim 1, characterized in that, With at least a portion of the spring arranged inside the bearing member, the bearing member rotatably supports the drive shaft.

3. The impact rotary tool according to claim 1 or 2, characterized in that, The bearing component is disposed between the hammer and the reduction mechanism along the axial direction of the drive shaft.

4. The impact rotary tool according to claim 1 or 2, characterized in that, The enlarged diameter section is configured to be continuous with and integral with the main body.

5. The impact rotary tool according to claim 1 or 2, characterized in that, The extension is disposed separately from at least the main body.

6. The impact rotary tool according to claim 1 or 2, characterized in that, The bearing component is configured as a support element. The extension is arranged inside the inner ring of the support member and is supported by the support member to rotate together with the inner ring.

7. The impact rotary tool according to claim 6, characterized in that, The extension includes an outwardly projecting protrusion along the 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.

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