Impact tool

Abstract

The problem to be overcome by the present disclosure is to further downsize an impact tool. The impact tool is provided with a motor (3) that generates a driving force, a main shaft (41) that holds a planetary gear (482) and is driven to rotate via the motor (3), an anvil (44) that is located on the opposite side of the planetary gear (482) in the axial direction of the rotation axis of the main shaft (41), a main hammer (42a) that is rotatable and movable along the central axis and rotates the anvil (44) around the rotation axis, a sub hammer (42b) that has a cylindrical portion (424) in which the main hammer (42a) is accommodated, a first bearing (493) that is arranged between the sub hammer (42b) and the main shaft (41) and receives a radial load applied in the radial direction with respect to the rotation axis, a gear base (5) that accommodates the planetary gear (482) and an internal gear, and a second bearing (492) that is arranged between the sub hammer (42b) and the gear base (5) to receive a load in the radial direction with respect to the rotation axis.

Description

Technical Field

[0001] This disclosure relates to impact tools. Background Technology

[0002] Patent Document 1 discloses an impact tool. The impact tool of Patent Document 1 includes: an inner hammer (main hammer) supported by a main shaft driven to rotate by a motor; and an outer hammer (secondary hammer) configured to rotate around and together with the inner hammer. In the impact tool of Patent Document 1, the outer hammer is supported by a hammer housing via a bearing.

[0003] However, in the impact tool of Patent Document 1, the spindle is supported by a bearing retainer shaft via a bearing at a position closer to the motor than the outer hammer, resulting in an overall larger size of the impact tool.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2023-90351 Summary of the Invention

[0007] The purpose of this disclosure is to further reduce the overall size of impact tools.

[0008] An impact tool according to one aspect of this disclosure includes a motor, a spindle, an anvil, a main hammer, a secondary hammer, a first bearing, a gear base, and a second bearing. The motor generates driving force. The spindle holds the planetary gears and is driven to rotate by the motor. The anvil is positioned on the opposite side of the planetary gears in an axial direction defined by the axis of rotation of the spindle. The main hammer is rotatable on and movable along a central axis defined by the axis of rotation of the spindle. The main hammer causes the anvil to rotate about the axis of rotation. The secondary hammer has a cylindrical portion in which the main hammer is housed, and the spindle is inserted through the cylindrical portion. The secondary hammer rotates integrally with the main hammer. The first bearing is disposed between the secondary hammer and the spindle to receive a load applied radially relative to the axis of rotation. The gear base houses not only the planetary gears but also an internal gear that engages with the planetary gears. The second bearing is disposed between the secondary hammer and the gear base to receive a load applied radially relative to the axis of rotation. Attached Figure Description

[0009] [ Figure 1 ] Figure 1 This is a perspective view showing an impact tool according to an embodiment.

[0010] [ Figure 2 ] Figure 2 This is a side cross-sectional view showing the impact tool.

[0011] [ Figure 3 ] Figure 3This is an exploded perspective view showing a portion of the impact tool.

[0012] [ Figure 4 ] Figure 4 This is an exploded perspective view showing the transmission mechanism of the impact tool. Detailed Implementation

[0013] This disclosure generally relates to an impact tool. More specifically, this disclosure relates to an impact tool comprising a housing in which a main hammer, a secondary hammer, and an anvil are housed.

[0014] (Implementation Method)

[0015] The impact tool according to embodiments will be described with reference to the accompanying drawings. Note that the embodiments described below are merely exemplary embodiments among the various embodiments of this disclosure and should not be construed as limiting. Rather, these exemplary embodiments can be readily modified in various ways according to design choices or any other factors without departing from the scope of this disclosure. It should also be noted that the drawings referenced in the following description of the embodiments are schematic representations. Therefore, the ratios of the dimensions (including thicknesses) of the various components illustrated in the drawings do not always reflect their actual dimensional ratios.

[0016] In the following description, such as Figure 2 The orientation of the motor 3 and spindle 41 arranged side-by-side, as shown below, will be defined as "front-to-back," where spindle 41 should be located in front of motor 3 and motor 3 should be located behind spindle 41. Furthermore, in the following description, as... Figure 1 As shown, the orientation of the second parts 22 and 23 and the handle 24, which are arranged vertically relative to each other, will be defined hereinafter as "vertical orientation," wherein the second parts 22 and 23 should be above the handle 24, and the handle 24 should be below the second parts 22 and 23. However, these definitions should not be construed as restricting the direction in which the impact tool should be used.

[0017] (Overview)

[0018] like Figures 1 to 4As shown, the impact tool 1 according to an exemplary embodiment includes a motor 3, a main shaft 41, an anvil 44, a main hammer 42a, a secondary hammer 42b, a first bearing 493, a gear base 5, and a second bearing 492. The motor 3 generates driving force. The main shaft 41 holds a planetary gear 482 and is driven to rotate by the motor 3. The anvil 44 is disposed on the opposite side of the planetary gear 482 of the main shaft 41 in an axial direction defined by the axis of rotation of the main shaft 41. The main hammer 42a is rotatable on and movable along a central axis defined by the axis of rotation of the main shaft 41. The main hammer 42a causes the anvil 44 to rotate about the axis of rotation. The secondary hammer 42b has a cylindrical portion 424 in which the main hammer 42a is housed, and the main shaft 41 is inserted through the cylindrical portion 424. The secondary hammer 42b rotates integrally with the main hammer 42a. The first bearing 493 is disposed between the secondary hammer 42b and the main shaft 41 to receive a load applied in a radial direction defined relative to the axis of rotation. The gear base 5 not only houses the planetary gear 482, but also the internal gear 483 that engages with the planetary gear 482. A second bearing 492 is disposed between the auxiliary hammer 42b and the gear base 5 to receive a load applied radially relative to the axis of rotation. The impact tool 1 according to this embodiment also includes a shim 6 disposed between the main shaft 41 and the gear base 5.

[0019] The impact tool 1 allows the load applied to the anvil 44 in the direction of thrust relative to the axis of rotation to be received at the gear base 5 via the spindle 41 and the shim 6 without affecting the rotary impact mechanism. Therefore, this improves the performance of the impact tool 1 when applying rotary impact force.

[0020] (detail)

[0021] (1) Overall structure

[0022] The impact tool 1 according to this embodiment will now be described in detail.

[0023] The impact tool 1 according to this embodiment is a portable power tool. The impact tool 1 can be, for example, an electric impact wrench, used to attach fastening components (such as bolts or nuts) to or loosen fastening components attached to a workpiece. Figures 1 to 4 As shown, the impact tool 1 includes a motor 3, a spindle 41, an anvil 44, a main hammer 42a, a secondary hammer 42b, a first bearing 493, a gear base 5, and a second bearing 492. The impact tool 1 also includes a housing 2, an operating member 83, and a torque sensor 47.

[0024] (2) Shell

[0025] like Figure 2 As shown, housing 2 houses motor 3, main shaft 41, anvil 44, main hammer 42a, auxiliary hammer 42b, first bearing 493, gear base 5, second bearing 492, and torque sensor 47 (see [reference]). Figure 3).like Figure 1 As shown, housing 2 includes a first portion 21, second portions 22 and 23, a third portion 221, a handle 24, and an attachment portion 25. The first portion 21 accommodates at least a portion of the anvil 44 and the torque sensor 47. The second portions 22 and 23 accommodate the motor 3. Note that the first portion 21 serves as a cover, and the second portions 22 and 23 and the third portion 221 form the outer casing.

[0026] The first part 21 and the second parts 22 and 23 are two separate components. The rear end of the first part 21 and the front end of the second parts 22 and 23 form a boundary where the first part 21 and the second parts 22 and 23 come into contact with each other. More specifically, as Figure 2 As shown, the inner peripheral surface of the front end portion 231 of the second part 22 and 23 covers the outer peripheral surface of the rear wall 215 of the first part 21.

[0027] Furthermore, the second parts 22 and 23 and the third part 221 are also two separate components. The rear ends of the second parts 22 and 23 and the front ends of the third part 221 form the boundary where the second parts 22 and 23 and the third part 221 come into contact with each other.

[0028] (2.1) Part 1

[0029] like Figure 1 and Figure 3 As shown, the first part 21 has a cylindrical shape and includes a front wall 211, a side wall 212, a rear wall 215, and four mounting members 213. The first part 21 corresponds to the cover according to this disclosure.

[0030] The front wall 211 has a cylindrical shape. An insertion hole 214 with a circular cross-section is configured to pass through the central portion of the front wall 211. An anvil shaft 441, which is housed in the first portion 21 (described later), is inserted through the insertion hole 214. The end (front end) of the anvil shaft 441 is located in front of the front end of the first portion 21. The side wall 212 has a cylindrical shape that extends rearward from the outer peripheral edge of the front wall 211.

[0031] Each of the four mounting pieces 213 is formed as a protrusion projecting outward from the periphery at the rear end of the sidewall 212. Each mounting piece 213 has an insertion hole for a screw B1 (see [link]). Figure 1 and Figure 3 Insert through the insertion hole.

[0032] The rear wall 215 has a cylindrical shape that extends rearward from the periphery at the rear end of the side wall 212. For example... Figure 2 As shown, the rear wall 215 is arranged within the second portions 22 and 23.

[0033] like Figure 2As shown, the first portion 21 has an internal space with a circular cross-section, surrounded by a front wall 211 and a side wall 212, and has an open rear surface. The first portion 21 houses at least a portion of an anvil 44 (described later) and a torque sensor 47 within the internal space. The internal space has a so-called "temple bell" shape, with its diameter larger at the rear end than at the front end, increasing towards the rear end.

[0034] (2.2) Part Two and Part Three

[0035] like Figure 1 and Figure 3 As shown, the second parts 22 and 23 have a cylindrical shape. The second parts 22 and 23 have sidewalls and four mounting members 223. The second parts 22 and 23 correspond to the housing according to this disclosure.

[0036] like Figure 2 As shown, the second parts 22 and 23 have an interior space with a circular cross-section, which is surrounded by sidewalls and has an open front and rear surface. The interior space has the shape of a column extending in the front-rear direction.

[0037] Each of the four mounting members 223 is formed as a protrusion extending outward from the periphery at the front end of the sidewall. Each of the mounting members 223 has a screw B1 (see...). Figure 1 and Figure 3 ) Screw holes for screw connections.

[0038] The first part 21 and the second parts 22 and 23 are connected to each other by screws. More specifically, the insertion holes of the four mounting pieces 213 for the first part 21 correspond one-to-one with the screw holes of the four mounting pieces 223 for the second parts 22 and 23, respectively. Figure 1 As shown. Each pair of corresponding insertion holes and screw holes are aligned with each other. Then, the first part 21 and the second parts 22 and 23 are connected to each other by inserting screw B1 through the insertion hole and screwing it into the screw hole.

[0039] Part 3, 221 has the following characteristics: Figure 1 The disc-shaped shape is shown. The third part 221 is arranged behind the second parts 22 and 23.

[0040] (2.3) Handle

[0041] Handle 24 protrudes from the second parts 22 and 23. More specifically, handle 24 protrudes from the side surfaces of the second parts 22 and 23. Handle 24 protrudes downward from the second parts 22 and 23. An operator can perform tightening operations on fastening components such as screws by gripping handle 24.

[0042] (2.4) Attachment

[0043] The attachment part 25 has such Figure 1 The tool is roughly rectangular in shape. An attachment 25 is connected to the lower end of the handle 24. A rechargeable battery pack (not shown) is removably attached to the attachment 25. The battery pack is used as a power source to power the impact tool 1. That is, the battery pack is the power source used to supply electricity to drive the motor 3. The battery pack may or may not be a component of the impact tool 1. The battery pack includes: an assembled battery formed by connecting multiple secondary batteries (e.g., lithium-ion batteries) in series; and a housing for accommodating the assembled battery.

[0044] (3) Motor

[0045] like Figure 2 As shown, motor 3 is housed within the internal space of the second portions 22 and 23 of housing 2. Motor 3 may be, for example, a brushless motor. Motor 3 includes: a rotor 31 comprising a rotating shaft 311 and a permanent magnet; and a stator 32 comprising coils. Due to the electromagnetic interaction between the permanent magnet and the coils, rotor 31 rotates relative to stator 32. The rotation of rotor 31 generates driving force for motor 3. Rotating shaft 311 is configured to extend in the front-rear direction. Rotation of rotor 31 triggers rotation of rotating shaft 311.

[0046] (4) Operating components

[0047] like Figure 1 As shown, the operating member 83 protrudes from the handle 24. The operating member 83 receives operations to control the rotation of the rotating shaft 311 of the motor 3. The motor 3 can be activated and deactivated by pulling the operating member 83. Furthermore, the rotational speed of the rotating shaft 311 can be adjusted according to the depth to which the operating member 83 is pulled. The deeper the operating member 83 is pulled, the higher the rotational speed of the rotating shaft 311.

[0048] (5) Transmission mechanism

[0049] The transmission mechanism includes an impact mechanism, a planetary gear mechanism 48, and a bearing 49. The bearing 49 includes a bearing 491, a second bearing 492, and a first bearing 493.

[0050] The impact mechanism is configured to perform an impact operation that applies an impact force in the rotational direction of the anvil 44 (described later) when the tightening torque (load torque) used to tighten the fastening member exceeds a predetermined value. The impact force is applied to an end tool (not shown) attached to the end of the anvil shaft 441 (described later). This allows a greater tightening torque to be applied to the fastening member. In other words, the impact tool 1 is an electrically operated impact wrench used to perform a tightening operation (such as tightening a screw) while using the impact mechanism to perform an impact operation.

[0051] The impact mechanism includes a main shaft 41, a main hammer 42a, a secondary hammer 42b, a helical spring 43, an anvil 44, and two steel balls 45 as two spherical components.

[0052] Planetary gear 482 of planetary gear mechanism 48 is located behind anvil 44 within housing 2 and is held by bracket of main shaft 41. That is, planetary gear 482 is held by main shaft 41. The bracket of main shaft 41 is located at the rear end of the two ends belonging to main shaft 41, opposite to the front end facing anvil 44. In other words, anvil 44 is positioned on the opposite side of planetary gear 482 in the axial direction defined by the rotation axis of main shaft 41.

[0053] The planetary gear mechanism 48 includes a sun gear 481, two planetary gears 482, and a ring internal gear 483, such as Figures 2 to 4 As shown. The sun gear 481 is located at the center of the internal gear 483 and is connected to the front end of the rotating shaft 311 of the motor 3 to rotate together with the rotating shaft 311. In this embodiment, the sun gear 481 is integrally formed with the front end of the rotating shaft 311 of the motor 3. The planet gears 482 mesh with the sun gear 481 and the internal gear 483 at a position between the sun gear 481 and the internal gear 483. The planet gears 482 rotate on their own axes and revolve around the internal gear 483 by the driving force transmitted from the sun gear 481. In front of the planet gear mechanism 48, a columnar main shaft 41 extending in the front-rear direction is arranged. The main shaft 41 is connected to the two planet gears 482. The revolute motion of the planet gears 482 is transmitted to the main shaft 41, thereby causing the main shaft 41 to rotate. Specifically, as Figure 2 and Figure 3 As shown, the corresponding shafts 484 of the two planetary gears 482 (see...) Figure 2 The gear is inserted through the rear end of the main shaft 41. That is, the main shaft 41 is connected to two planetary gears 482.

[0054] The planetary gear mechanism 48 is a speed reducer that converts the rotational speed and torque of the rotating shaft 311 of the motor 3 into the rotational speed and torque of the rotating fastening member. The torque of the rotating shaft 311 of the motor 3 is transmitted to the main shaft 41 via the planetary gear mechanism 48, thereby causing the main shaft 41 to rotate.

[0055] Two grooves, each with a semi-circular cross-section, are provided on the outer circumferential surface of the main shaft 41. Each of the two grooves extends on the outer circumferential surface of the main shaft 41 and forms an inclination angle relative to the direction intersecting the axial direction.

[0056] The main hammer 42a is made of metal. The anvil 44 is rotated by the torque transmitted via the main shaft 41. In addition, the main hammer 42a also moves (translates) relative to the anvil 44 in the back-and-forth direction during rotation, thereby applying an impact force to the anvil 44 in the direction of rotation.

[0057] Specifically, such as Figure 2 As shown, the main hammer 42a includes a pair of protruding hammer claws 421. The pair of hammer claws 421 are arranged at 180-degree intervals. A through hole 422, penetrating through the central portion of the main hammer 42a in the front-rear direction, is formed by a cylindrical member extending in the front-rear direction. The through hole 422 has a circular cross-section. The main shaft 41 penetrates the through hole 422 in the front-rear direction.

[0058] Two grooves 423, each with a semi-circular cross-section, are provided on the inner circumferential surface of the through hole 422 of the main hammer 42a (see...). Figure 2 Each of the two grooves 423 extends on the inner circumferential surface of the through hole 422 to form an inclination angle relative to the direction intersecting the axial direction.

[0059] Two steel balls 45 are respectively sandwiched between two slots of the main shaft 41 and two slots 423 of the main hammer 42a. Each of the steel balls 45 has a spherical shape. The two slots of the main shaft 41, the two slots 423 of the main hammer 42a, and the two steel balls 45 together form a cam mechanism. That is, the torque of the main shaft 41 is transmitted to the main hammer 42a via the two steel balls 45, thereby rotating the main hammer 42a. In addition, the steel balls 45 are received in cam grooves formed by the slots and slots 423 of the main shaft 41 and can move along the cam grooves. Moving the two steel balls 45 along the cam grooves allows the main hammer 42a to move axially (i.e., in the front-to-back direction) relative to the main shaft 41. Note that the two cam grooves are symmetrical to each other with respect to a virtual plane intersecting the axis defined by the main shaft 41.

[0060] A helical spring 43 is positioned behind the main hammer 42a. The helical spring 43 applies a spring force to the main hammer 42a in the forward direction. The main hammer 42a moves backward by overcoming the spring force applied by the helical spring 43. The spring force causes the backward-moving main hammer 42a to move forward.

[0061] The secondary hammer 42b is made of metal. The secondary hammer 42b rotates integrally with the main hammer 42a. The secondary hammer 42b includes a cylindrical portion 424. The cylindrical portion 424 houses the main hammer 42a, the helical spring 43, and the anvil body 440 of the anvil 44. Furthermore, the cylindrical portion 424 of the secondary hammer 42b has a through hole extending through it in the front-rear direction. The through hole has a circular cross-section. The main shaft 41 extends through the through hole in the front-rear direction.

[0062] The secondary hammer 42b includes a peripheral portion 425 that protrudes (i.e., rearwards) toward the motor 3. The peripheral portion 425 has a cylindrical shape. The inner circumferential surface of the peripheral portion 425 of the secondary hammer 42b is supported by a first bearing 493 (see...). Figure 2Shaft support. A first bearing 493 pivotally supports the secondary hammer 42b. The first bearing 493 can be configured, for example, as a ball bearing supporting the inner circumference of the secondary hammer 42b. The first bearing 493 receives a load applied radially along the axis of rotation relative to the main shaft 41. Furthermore, the first bearing 493 reduces the wobbling, chattering, and other unintentional movements of the secondary hammer 42b.

[0063] Anvil 44 is positioned in front of main hammer 42a. Anvil 44 includes anvil body 440 and anvil shaft 441. Anvil body 440 and anvil shaft 441 are made of metal. Anvil body 440 and anvil shaft 441 rotate by torque transmitted from main hammer 42a.

[0064] The anvil body 440 includes a pair of anvil claws 442. The pair of anvil claws 442 are arranged at a 180-degree interval to project radially as defined by the anvil body 440. The anvil body 440 faces the main hammer 42a in the front-rear direction. As the main hammer 42a rotates, the anvil claws 442 collide with the hammer claws 421 in the direction of rotation of the main hammer 42a.

[0065] Anvil shaft 441 is axially arranged in front of the front surface of anvil body 440. Anvil shaft 441 is an output shaft that rotates synchronously with anvil body 440. An end tool (not shown) is attached to the end (front end) of anvil shaft 441. That is, anvil shaft 441 has a structure that allows the end tool to be held at its end in the direction defined by the axis of rotation of master hammer 42a. The end tool may be, for example, a bit for turning fastening components such as bolts or nuts.

[0066] The corresponding outer peripheral surfaces of the anvil shaft 441 and the anvil body 440 are supported by the bearing 491 (see [link]). Figure 2 Bearing 491 pivotally supports anvil shaft 441. Bearing 491 may be configured, for example, as a roller bearing for supporting the respective outer circumferences of the anvil body 440 and anvil shaft 441. Bearing 491 reduces wobbling, chattering, and other unintentional movements of the rotating anvil body 440 and anvil shaft 441. Note that bearing 491 may have a configuration for pivotally supporting at least anvil shaft 441.

[0067] Rotating the spindle 41 using the torque transmitted from the motor 3 to the spindle 41 via the planetary gear mechanism 48 allows the torque to be transmitted from the spindle 41 to the hammer 42a via the aforementioned cam mechanism, causing the hammer 42a to rotate about the spindle 41 as its axis of rotation. Unless the hammer 42a is performing an impact operation, the hammer 42a and the anvil body 440 rotate integrally with each other, wherein a pair of hammer pawls 421 of the hammer 42a remain in contact with a pair of anvil pawls 442 of the anvil body 440 in the direction of rotation. Rotation of the anvil body 440 also causes the anvil shaft 441 and the end tool to rotate. Therefore, the fastening member is also rotated by the torque applied by the end tool.

[0068] Then, as the fastening member rotates to be fastened and screwed into the screw hole, for example, not only the axial force of the fastening member but also the fastening torque increases accordingly. As the fastening torque increases, the component of the force generated between the main hammer 42a and the anvil body 440 that causes the main hammer 42a to retract increases. Then, when the fastening torque increases to a value equal to or greater than a predetermined value, the main hammer 42a begins to move backward by overcoming the spring force applied by the helical spring 43. As the main hammer 42a moves backward, it rotates, and simultaneously, a pair of hammer claws 421 of the main hammer 42a passes over the two anvil claws 442 of the anvil body 440. Then, the spring force applied by the helical spring 43 causes the main hammer 42a to move forward. When the spindle 41 rotates approximately half a turn, the pair of hammer claws 421 of the main hammer 42a collide with the side surfaces of a pair of anvil claws 442. That is, every time the spindle 41 rotates approximately half a turn, the hammer claws 421 collide with the anvil claws 442. In other words, whenever the spindle 41 rotates about half a turn, the main hammer 42a applies an impact force (rotational impact force) to the anvil body 440 while repeatedly moving back and forth.

[0069] (6) Control unit

[0070] The control unit includes a torque sensor 47. The torque sensor 47 measures the torque applied to the anvil shaft 441. The control unit controls the rotational speed of the rotating shaft 311 by performing, for example, feedback control, through which the torque of the anvil shaft measured by the torque sensor 47 is controlled to be close to a target value. The control unit changes the rotational speed of the rotating shaft 311, for example, by changing the power supplied to the motor 3.

[0071] (7) Gear base

[0072] The gear base 5 is housed in the housing 2 and held by the housing 2 in a position between the auxiliary hammer 42b and the motor 3.

[0073] The gear base 5 has a cylindrical shape and includes a rear wall 51 and a side wall 52, as shown below. Figures 2 to 4 As shown. The rear wall 51 has a disc-shaped shape. The rear wall 51 has a through hole through which the rotating shaft 311 of the motor 3 is inserted. The side wall 52 has a cylindrical shape extending forward from the outer peripheral edge of the rear wall 51.

[0074] Planetary gear mechanism 48 is housed within the sidewall 52 of gear base 5. Specifically, gear base 5 houses planetary gear 482 and an internal gear 483 that engages with planetary gear 482. The annular internal gear 483 of planetary gear mechanism 48 is mounted to sidewall 52 along its inner circumferential surface 522. The sun gear 481 of planetary gear mechanism 48 is located at the center of the annular internal gear 483. The front end of the rotating shaft 311 of motor 3 engages with the rear end of sun gear 481, causing sun gear 481 to rotate together with rotating shaft 311. Two planetary gears 482 of planetary gear mechanism 48 mesh with sun gear 481 and internal gear 483 at a position between sun gear 481 and internal gear 483. Main shaft 41 passes through corresponding shafts 484 of the two planetary gears 482 (see...). Figure 2 It is inserted through the main shaft 41 and connected to the two planetary gears 482.

[0075] In addition, a shim 6 is provided between the rear wall 51 of the gear base 5 and the main shaft 41 (see reference). Figure 2 and Figure 3 The shim 6 can have, for example, an annular shape. Therefore, the impact tool 1 can receive the load applied to the anvil 44 in the thrust direction relative to the axis of rotation at the gear base 5 via the spindle 41 and the shim 6, without affecting the rotary impact mechanism. This improves the performance of the impact tool 1 when applying a rotary impact force. Furthermore, it prevents overheating, jamming, and other inconveniences caused by slippage between the spindle 41 and the gear base 5. Alternatively, the impact tool 1 can comprise a thrust ball bearing or a thrust roller bearing instead of the shim 6. This configuration also improves the performance of the impact tool 1 when a rotary impact force is applied as described above.

[0076] Furthermore, the second bearing 492 is also arranged within the side wall 52 of the gear base 5. The outer peripheral surface of the auxiliary hammer 42b is axially supported by the second bearing 492 (see...). Figure 2 The second bearing 492 pivotally supports the auxiliary hammer 42b. The second bearing 492 can be configured, for example, as a ball bearing for axial support of the outer periphery of the auxiliary hammer 42b. The second bearing 492 receives a load applied radially relative to the axis of rotation of the main shaft 41. Furthermore, the second bearing 492 reduces wobbling, chattering, and other unintentional movements of the auxiliary hammer 42b. Additionally, the second bearing 492 is configured to overlap the first bearing 493 in the axial direction defined by the axis of rotation of the main shaft 41, as... Figure 2 As shown. This allows for a reduction in the length of the transmission mechanism measured axially by the axis of rotation of the spindle 41. Therefore, this allows for a reduction in the length of the impact tool 1 measured in the front-to-back direction.

[0077] In this embodiment, the inner circumferential surface of the second bearing 492 is in close contact with the outer circumferential surface of the auxiliary hammer 42b. A gap is left between the outer circumferential surface of the second bearing 492 and the inner circumferential surface 522 of the gear base 5. This allows the second bearing 492 and the auxiliary hammer 42b to be treated as integral components when the impact tool 1 is assembled or disassembled, thereby making it easier to handle the impact tool 1.

[0078] Furthermore, the outer peripheral surface of the sidewall 52 of the gear base 5 is covered by the inner peripheral surface of the rear wall 215 of the first portion 21. As described above, the inner peripheral surface of the front end portion 231 of the second portions 22 and 23 covers the outer peripheral surface of the rear wall 215 of the first portion 21. Therefore, the sidewall 52 of the gear base 5 is covered by the inner peripheral surface of the rear wall 215 of the first portion 21. This makes it easier to attach and separate the first portion 21 and the gear base 5 while maintaining sufficient shaft support accuracy during the manufacture and maintenance of the impact tool 1. In addition, in this embodiment, the gear base 5 is clamped between the first portion 21 and the second portions 22, 23, thereby allowing the gear base 5 to be fixed to the housing 2 even without the use of any screws or claws. This makes it easier to assemble and disassemble the impact tool 1.

[0079] At least a portion of the gear base 5 is made of metal. The gear base 5 can be made of, for example, aluminum alloy. In particular, due to the sound insulation properties of the gear base 5, this allows noise that would otherwise reach the ears of the user of the impact tool 1 to be cut off. Therefore, the impact tool 1 is allowed to operate with lower noise.

[0080] (8) Advantages

[0081] The impact tool 1 according to the first embodiment includes a motor 3, a main shaft 41, an anvil 44, a main hammer 42a, a secondary hammer 42b, a first bearing 493, a gear base 5, and a second bearing 492. The motor 3 generates driving force. The main shaft 41 holds a planetary gear 482 and is driven to rotate by the motor 3. The anvil 44 is disposed on the opposite side of the planetary gear 482 in an axial direction defined by the rotation axis of the main shaft 41. The main hammer 42a is rotatable on and movable along a central axis defined by the rotation axis of the main shaft 41. The main hammer 42a causes the anvil 44 to rotate about the rotation axis. The secondary hammer 42b has a cylindrical portion 424 in which the main hammer 42a is housed, and the main shaft 41 is inserted through the cylindrical portion 424. The secondary hammer 42b rotates integrally with the main hammer 42a. The first bearing 493 is disposed between the secondary hammer 42b and the main shaft 41 to receive a load applied radially relative to the rotation axis. The gear base 5 not only houses the planetary gear 482, but also the internal gear 483 that engages with the planetary gear 482. The second bearing 492 is disposed between the auxiliary hammer 42b and the gear base 5 to receive the load applied in the radial direction defined relative to the axis of rotation.

[0082] Therefore, if the main shaft 41, the secondary hammer 42b, and the gear base 5 are arranged side by side in the radial direction defined relative to the axis of rotation, the first bearing 493 and the second bearing 492 are configured to overlap each other in the axial direction defined by the axis of rotation. This allows for a miniaturization of the overall size of the impact tool 1.

[0083] Furthermore, the impact tool 1 according to the first embodiment also includes a shim 6 disposed between the spindle 41 and the gear base 5.

[0084] Therefore, the impact tool 1 allows the load applied to the anvil 44 in the thrust direction relative to the axis of rotation to be received at the gear base 5 via the spindle 41 and the washer 6 without affecting the rotary impact mechanism. This improves the performance of the impact tool 1 when applying rotary impact force. Furthermore, the impact tool 1 reduces the chance of jamming and other inconveniences caused by slippage between the spindle 41 and the gear base 5.

[0085] Furthermore, the impact tool 1 according to the first embodiment also includes housings 22 and 23 and a cover 21. Housings 22 and 23 house the motor 3. Cover 21 houses the auxiliary hammer 42b. The inner circumferential surface of cover 21 covers the outer circumferential surface 521 of the gear base 5. The inner circumferential surfaces of housings 22 and 23 cover the outer circumferential surface of cover 21. This makes it easier to attach and detach the first part 21 and the gear base 5 while maintaining sufficient shaft support accuracy during the manufacture and maintenance of the impact tool 1. Furthermore, in this embodiment, the gear base 5 is clamped between the first part 21 and the second parts 22 and 23, thereby allowing the gear base 5 to be secured to the housing 2 even without the use of any screws or claws. This makes it easier to assemble and disassemble the impact tool 1.

[0086] Furthermore, in the impact tool 1 according to the first embodiment, the inner circumferential surface of the second bearing 492 is in close contact with the outer circumferential surface of the auxiliary hammer 42b. A gap is left between the outer circumferential surface of the second bearing 492 and the inner circumferential surface of the gear base 5. This allows the second bearing 492 and the auxiliary hammer 42b to be handled as integral components when the impact tool 1 is assembled or disassembled, thereby making the impact tool 1 easier to handle.

[0087] Furthermore, in the impact tool 1 according to the first embodiment, the material used for the gear base 5 includes metal. The impact tool 1 allows for operation with lower noise because the gear base 5 has sound-insulating properties.

[0088] Furthermore, in the impact tool 1 according to the first embodiment, the anvil 44 includes an anvil body 440 and an anvil shaft 441 disposed separately from the anvil body 440. The anvil body 440 is rotated by the main hammer 42a. The anvil shaft 441 is rotated by the anvil body 440. Therefore, by reducing the vibration of the anvil shaft 441 caused by the main hammer 42a, the impact tool 1 is allowed to operate with lower noise.

[0089] Furthermore, the impact tool 1 according to the first embodiment also includes a torque sensor 47. The torque sensor 47 measures the torque of the anvil 44. This allows the impact tool 1 to control the rotational speed of the anvil 44, for example, by performing feedback control.

[0090] (aspect)

[0091] The impact tool (1) according to the first aspect includes a motor (3), a main shaft (41), an anvil (44), a main hammer (42a), a secondary hammer (42b), a first bearing (493), a gear base (5), and a second bearing (492). The motor (3) generates driving force. The main shaft (41) holds the planetary gear (482) and is driven to rotate by the motor (3). The anvil (44) is arranged on the opposite side of the planetary gear (482) in an axial direction defined by the rotation axis of the main shaft (41). The main hammer (42a) is rotatable on a central axis defined by the rotation axis of the main shaft (41) and is movable along the central axis. The main hammer (42a) causes the anvil (44) to rotate about the rotation axis. The secondary hammer (42b) has a cylindrical portion (424) in which the main hammer (42a) is housed, and the main shaft (41) is inserted through the cylindrical portion (424). The secondary hammer (42b) rotates integrally with the main hammer (42a). A first bearing (493) is disposed between the secondary hammer (42b) and the main shaft (41) to receive the load applied radially relative to the axis of rotation. The gear base (5) houses not only the planetary gear (482) but also the internal gear (483) that engages with the planetary gear (482). A second bearing (492) is disposed between the secondary hammer (42b) and the gear base (5) to receive the load applied radially relative to the axis of rotation.

[0092] According to this aspect, the impact tool (1) allows for the following: if the main shaft (41), the secondary hammer (42b), and the gear base (5) are arranged side by side in a radial direction defined relative to the axis of rotation, the first bearing (493) and the second bearing (492) are configured to overlap each other in an axial direction defined by the axis of rotation. Therefore, this allows for the miniaturization of the overall size of the impact tool (1).

[0093] The impact tool (1) that can be implemented in conjunction with the first aspect also includes a shim (6) disposed between the spindle (41) and the gear base (5).

[0094] The impact tool (1) according to this aspect allows the load applied to the anvil (44) in the direction of thrust relative to the axis of rotation to be received at the gear base (5) via the spindle (41) and the washer (6). Therefore, this improves the performance of the impact tool (1) when applying rotational impact force. In addition, the impact tool (1) according to this aspect can also reduce the chance of jamming and other inconveniences caused by slippage between the spindle (41) and the gear base (5).

[0095] The impact tool (1), which can be implemented in conjunction with the first or second aspect, also includes a housing (22, 23) and a cover (21). The housing (22, 23) houses the motor (3). The cover (21) houses the auxiliary hammer (42b). The inner circumferential surface of the cover (21) covers the outer circumferential surface of the gear base (5). The inner circumferential surface of the housing (22, 23) covers the outer circumferential surface of the cover (21).

[0096] The impact tool (1) according to this aspect makes it easier to attach and detach the cover (21) and the gear base (5) in a manner that maintains sufficient shaft support accuracy during the manufacture and maintenance of the impact tool (1). Furthermore, according to this aspect, the gear base (5) is clamped between the cover (21) and the housing (22, 23). This makes it easier to assemble and disassemble the impact tool (1).

[0097] In the impact tool (1) according to the fourth aspect, which can be implemented in combination with any of the first to third aspects, the inner circumferential surface of the second bearing (492) is in close contact with the outer circumferential surface of the auxiliary hammer (42b). A gap is left between the outer circumferential surface of the second bearing (492) and the inner circumferential surface of the gear base (5).

[0098] According to this aspect, the impact tool (1) allows the second bearing (492) and the auxiliary hammer (42b) to be handled as integral components when the impact tool (1) is assembled or disassembled, thereby making it easier to handle the impact tool (1).

[0099] In the impact tool (1) according to the fifth aspect, which can be implemented in conjunction with any of the first to fourth aspects, the material for the gear base (5) includes metal.

[0100] The impact tool (1) allows for operation with lower noise because the gear base (5) has sound insulation properties.

[0101] In the impact tool (1) according to the sixth aspect which can be implemented in conjunction with any of the first to fifth aspects, the anvil (44) includes an anvil body (440) and an anvil shaft (441). The anvil body (440) is rotated by the main hammer (42a). The anvil shaft (441) is rotated by the anvil body (440).

[0102] By reducing the vibration of the anvil shaft (441) caused by the main hammer (42a), the impact tool (1) in this respect is allowed to operate with lower noise.

[0103] The impact tool (1) according to the seventh aspect, which can be implemented in conjunction with any of the first to sixth aspects, also includes a torque sensor (47). The torque sensor (47) measures the torque of the anvil (44).

[0104] The impact tool (1) allows the rotational speed of the anvil (44) to be controlled, for example, by performing feedback control.

[0105] Explanation of reference numerals in the attached figures

[0106] 1. Impact tool

[0107] 21 Part One (Lid)

[0108] 22, 23 Part Two (Outer Shell)

[0109] 3 motors

[0110] 41 Spindle

[0111] 42a Main Hammer

[0112] 42b Secondary hammer

[0113] 424 Cylindrical section

[0114] 44 anvil

[0115] 440 Anvil body

[0116] 441 Anvil

[0117] 47 Torque Sensor

[0118] 482 Planetary Gears

[0119] 483 Internal Gear

[0120] 493 First Bearing

[0121] 492 Second Bearing

[0122] 5 Gear base

[0123] 521 Outer Peripheral Surface

[0124] 6 gaskets

Claims

1. An impact tool, comprising: A motor is constructed to generate driving force; A main shaft, configured to hold planetary gears and constructed to be driven to rotate by the motor; An anvil, which is disposed on the opposite side of the planetary gear in an axial direction defined by the rotation axis of the main shaft; The main hammer is configured to rotate on and move along a central axis defined by the axis of rotation of the main shaft, and the main hammer is configured to cause the anvil to rotate about the axis of rotation. A secondary hammer, configured to rotate integrally with the main hammer and having a cylindrical portion, the main hammer being housed within the cylindrical portion and the main shaft being inserted through the cylindrical portion; A first bearing is disposed between the secondary hammer and the main shaft to receive a load applied in the radial direction defined relative to the axis of rotation; A gear base configured to accommodate not only the planetary gear, but also an internal gear that engages with the planetary gear; as well as A second bearing is disposed between the secondary hammer and the gear base to receive a load applied in the radial direction defined relative to the axis of rotation.

2. The impact tool according to claim 1 further includes a shim disposed between the spindle and the gear base.

3. The impact tool according to claim 1 or 2, further comprising: A housing configured to house the motor; as well as A cover, configured to accommodate the secondary hammer, wherein The inner circumferential surface of the cover covers the outer circumferential surface of the gear base, and The inner circumferential surface of the outer shell covers the outer circumferential surface of the cover.

4. The impact tool according to any one of claims 1 to 3, wherein, The inner circumferential surface of the second bearing is in close contact with the outer circumferential surface of the auxiliary hammer, and A gap is left between the outer peripheral surface of the second bearing and the inner peripheral surface of the gear base.

5. The impact tool according to any one of claims 1 to 4, wherein The materials used for the gear base include metals.

6. The impact tool according to any one of claims 1 to 5, wherein The anvil includes: The anvil body is configured to rotate by the main hammer; as well as The anvil shaft is configured to rotate by the anvil body.

7. The impact tool according to any one of claims 1 to 6, further comprising a torque sensor configured to measure the torque of the anvil.

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