Impact rotary tool

Abstract

To suppress occurrence of collision sound due to a collision between an anvil and an output shaft.SOLUTION: An impact rotating tool 1 comprises a hammer 5, an anvil 6, an output shaft 7, a housing 2, a bearing (a first bearing 91), and a buffering member 8. The buffering member 8 includes an elastic member 81. The anvil 6 has a first opposing region. The output shaft 7 has a second opposing region. The buffering member 8 is sandwiched between the anvil 6 and the output shaft 7. When the maximum load transmitted from the hammer 5 is acting on the elastic member 81, the buffering member 8 regulates a distance between the second opposing region and the first opposing region so that the second opposing region opposes to the first opposing region with a clearance in a thrust direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates generally to impact rotary tools, and more particularly, to an impact rotary tool including a hammer and an anvil. [Background technology]

[0002] The rotary impact tool (impact rotary tool) described in Patent Document 1 has a rotary impact force generating mechanism attached to a spindle connected to a drive motor via a reduction gear device, and rotary impacts one end of an anvil equipped with a means for connecting a tool tip. The rotary impact tool is characterized in that the anvil is separated into a rotary impact member and a tool tip mounting member (output shaft), a torque transmission section is formed between the rotary impact member and the tool tip mounting member, and an elastic material or cushioning material is interposed in the axial gap between the rotary impact member and the tool tip mounting member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 07-237152 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a rotary impact tool that can suppress the generation of collision noise caused by collision between an anvil and an output shaft. [Means for solving the problem]

[0005] A rotary impact tool according to an embodiment of the present disclosure includes a hammer, an anvil, an output shaft, a housing, a bearing, and a buffer member. The hammer rotates by receiving power from a motor. The anvil rotates by receiving a striking force from the hammer in the rotation direction of the hammer. The output shaft is configured to hold a tool tip, and rotates together with the anvil by receiving a force from the anvil in the rotation direction of the anvil. The housing accommodates the hammer and the anvil. The bearing is held by the housing and rotatably supports the output shaft. The buffer member includes an elastic member that elastically deforms in a thrust direction that is a direction along the rotation axis of the output shaft. The anvil has a first opposing region that faces the output shaft in the thrust direction. The output shaft has a second opposing region that faces the first opposing region in the thrust direction. The buffer member is sandwiched between the anvil and the output shaft. The elastic member is compressed in the thrust direction by the load in the thrust direction transmitted from the hammer. When the maximum load transmitted from the hammer is applied to the elastic member, the buffer member regulates the distance between the second opposing region and the first opposing region such that the second opposing region faces the first opposing region with a gap therebetween in the thrust direction. The bearing is in contact with the output shaft and the anvil. Effect of the Invention

[0006] The present disclosure has the advantage of being able to suppress the generation of collision noise caused by the anvil colliding with the output shaft. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of a rotary impact tool according to one embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of the rotary impact tool. [Diagram 3] FIG. 3 is a front view of a main part of the rotary impact tool. [Figure 4]FIG. 4 is an exploded perspective view of a main part of the rotary impact tool as viewed from the front. [Diagram 5] FIG. 5 is an exploded perspective view of a main part of the rotary impact tool as viewed from the rear. [Figure 6] FIG. 6 is a perspective view of an anvil and an output shaft of the rotary impact tool. [Figure 7] FIG. 7 is a sectional perspective view of an anvil and an output shaft of the rotary impact tool. [Figure 8] FIG. 8 is a sectional perspective view of an anvil and an output shaft of the rotary impact tool. [Figure 9] FIG. 9 is an exploded perspective view of a main part of the rotary impact tool according to the first modification. [Figure 10] FIG. 10 is a cross-sectional view of a main part of a rotary impact tool according to the second modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (Embodiment) The impact rotary tool 1 according to the embodiment will be described below with reference to the drawings. However, the embodiment described below is merely one of various embodiments of the present disclosure. The embodiment described below can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Also, each figure described in the embodiment described below is a schematic diagram, and the size and thickness ratios of each component in the figure do not necessarily reflect the actual dimensional ratios.

[0009] (overview) As shown in FIG. 1 and FIG. 2, the impact rotary tool 1 of this embodiment includes a hammer 5, an anvil 6, an output shaft 7, a housing 2, a bearing (first bearing 91), and a buffer member 8. The hammer 5 receives power from a motor 3 to rotate. The anvil 6 receives a striking force from the hammer 5 in the rotational direction of the hammer 5 to rotate. The output shaft 7 is configured to hold a tool tip, and receives a force from the anvil 6 in the rotational direction of the anvil 6 to rotate together with the output shaft 7. The housing 2 accommodates the hammer 5 and the anvil 6. The bearing (first bearing 91) is held by the housing 2 and rotatably supports the output shaft 7. The buffer member 8 includes an elastic member 81 that elastically deforms in a thrust direction, which is a direction along the rotation axis of the output shaft 7. The anvil 6 has a first opposing region F1 (see FIG. 7) that faces the output shaft 7 in the thrust direction. The output shaft 7 has a second opposing region F2 (see FIG. 7) that faces the first opposing region F1 in the thrust direction. The buffer member 8 is sandwiched between the anvil 6 and the output shaft 7. The elastic member 81 is compressed in the thrust direction by the load in the thrust direction transmitted from the hammer 5. When the maximum load transmitted from the hammer 5 is applied to the elastic member 81, the buffer member 8 regulates the distance between the second opposing region F2 and the first opposing region F1 such that the second opposing region F2 faces the first opposing region F1 with a gap therebetween in the thrust direction.

[0010] The above configuration reduces the possibility that the anvil 6 will collide with the output shaft 7. This reduces the possibility that collision noise will occur and that vibrations due to the collision will be transmitted to the housing 2. Furthermore, the vibrations of the anvil 6 in the thrust direction are attenuated by the buffer member 8 before being transmitted to the output shaft 7, so that the vibrations of the output shaft 7 can be suppressed.

[0011] The impact rotary tool 1 of this embodiment includes a hammer 5, an anvil 6, an output shaft 7, a housing 2, and a bearing (first bearing 91). The hammer 5 receives power from the motor 3 to rotate. The anvil 6 receives impact force from the hammer 5 in the rotational direction of the hammer 5 to rotate. The output shaft 7 is configured to hold a tool tip, and receives force from the anvil 6 in the rotational direction of the anvil 6 to rotate together with the output shaft 7. The housing 2 accommodates the hammer 5 and the anvil 6. The bearing (first bearing 91) is held by the housing 2. The anvil 6 includes a first contact portion 63. The first contact portion 63 contacts the output shaft 7. The output shaft 7 includes a second contact portion 72. The second contact portion 72 contacts the first contact portion 63. The second contact portion 72 receives force from the first contact portion 63 to rotate the output shaft 7. The bearing (first bearing 91) is in contact with at least one of the first contact portion 63 and the second contact portion 72, and rotatably supports at least one of the output shaft 7 and the anvil 6.

[0012] According to the above configuration, at least one of the first contact portion 63 and the second contact portion 72 is in contact with the bearing (first bearing 91), thereby reinforcing the mechanical strength. In particular, at least one of the first contact portion 63 and the second contact portion 72 is reinforcing the mechanical strength against vibration in the radial direction of the output shaft 7. This improves the durability of at least one of the anvil 6 and the output shaft 7.

[0013] (detail) (1) Overall structure The rotary impact tool 1 of this embodiment will be described in detail below.

[0014] In the following description, the direction in which the anvil 6 and the output shaft 7 are aligned is defined as the front-rear direction, the output shaft 7 side as viewed from the anvil 6 is defined as the front, and the anvil 6 side as viewed from the output shaft 7 is defined as the rear. In the following description, the direction in which the housing section 21 and the grip section 22 are aligned is defined as the up-down direction, the housing section 21 side as viewed from the grip section 22 is defined as the top, and the grip section 22 side as viewed from the housing section 21 is defined as the bottom. In addition, the direction perpendicular to the front-rear direction and the up-down direction is defined as the left-right direction. However, these definitions are not intended to define the direction in which the impact rotary tool 1 is used. In addition, the arrows representing the front-rear direction and the up-down direction in FIG. 2 are merely indicated for the purpose of explanation and do not have any substance.

[0015] Moreover, the thrust direction in this disclosure refers to a direction along the rotation axis of the output shaft 7. The thrust direction is a direction along the front-rear direction.

[0016] The impact rotary tool 1 of this embodiment is a portable power tool. As shown in Figures 1 and 2, the impact rotary tool 1 includes a housing 2, a motor 3, a transmission mechanism 4, a hammer 5, an anvil 6, an output shaft 7, a buffer member 8, a first bearing 91, a second bearing 92, a first stopper 93, a second stopper 94, a drive circuit 11, a control circuit 12, and an operation unit 13.

[0017] (2) Housing The housing 2 accommodates the motor 3, the transmission mechanism 4, the hammer 5, the anvil 6, the buffer member 8, the first bearing 91, the second bearing 92, the first stopper 93, the second stopper 94, the drive circuit 11, and the control circuit 12. As shown in FIG 1, the housing 2 has an accommodating portion 21, a grip portion 22, and an attachment portion 23.

[0018] The accommodation portion 21 has a hollow cylindrical shape. The accommodation portion 21 includes a first accommodation portion 211 and a second accommodation portion 212. The first accommodation portion 211 is provided in front of the second accommodation portion 212. The first accommodation portion 211 is connected to the second accommodation portion 212. The first accommodation portion 211 accommodates at least the hammer 5 and the anvil 6. The first accommodation portion 211 holds a first bearing 91 and a second bearing 92. The first accommodation portion 211 has a through hole 2110 through which the output shaft 7 passes.

[0019] The grip portion 22 protrudes from the outer circumferential surface of the housing portion 21 in one direction along one radial direction of the housing portion 21. More specifically, the grip portion 22 protrudes from the second housing portion 212. The one direction is along the up-down direction. The grip portion 22 is formed in a hollow cylindrical shape that is long in the one direction. An operator can grasp the grip portion 22 to perform operations such as screw tightening. In addition, the grip portion 22 holds an operation unit 13 that accepts operations by the operator.

[0020] The internal space of the grip portion 22 is connected to the internal space of the storage portion 21. One end of the grip portion 22 in the longitudinal direction is connected to the storage portion 21, and the other end is connected to the mounting portion 23.

[0021] A battery pack is detachably attached to the mounting portion 23. The impact rotary tool 1 operates using the battery pack as a power source. That is, the battery pack is a power source that supplies a current to drive the motor 3. The battery pack is not a component of the impact rotary tool 1. However, the impact rotary tool 1 may be equipped with a battery pack.

[0022] (3) Motor As shown in Fig. 2, the motor 3 is accommodated in the accommodating portion 21 of the housing 2. The motor 3 is, for example, a brushless motor. The motor 3 includes a rotor 31 having a rotating shaft 311 and a permanent magnet, and a stator 32 having a coil. The rotor 31 rotates relative to the stator 32 due to electromagnetic interaction between the permanent magnet and the coil.

[0023] The motor 3 is a servo motor. The torque and rotation speed of the motor 3 change according to the control by the control circuit 12 (see FIG. 1). The control circuit 12 is a servo driver. The control circuit 12 controls the operation of the motor 3 by feedback control that controls the torque and rotation speed of the motor 3 to approach target values.

[0024] The worker operates the operating unit 13. Specifically, the worker retracts the operating unit 13. The control circuit 12 determines a target value of the rotation speed of the motor 3 according to the retraction amount of the operating unit 13. The larger the retraction amount, the larger the control circuit 12 sets the target value of the rotation speed of the motor 3.

[0025] The drive circuit 11 (see FIG. 2) includes a substrate and a plurality of electronic components mounted on the substrate. The plurality of electronic components include a plurality of power elements that configure an inverter circuit. Each of the power elements is, for example, a FET (Field Effect Transistor) element.

[0026] The control circuit 12 controls the motor 3 via the drive circuit 11. That is, the control circuit 12 controls the power supplied to the motor 3 via a plurality of power elements (inverter circuits) by switching the plurality of power elements of the drive circuit 11 on and off.

[0027] (4) Transmission mechanism 2, the transmission mechanism 4 is accommodated in the accommodating portion 21 of the housing 2. The transmission mechanism 4 transmits the power of the motor 3 to the hammer 5. This causes the hammer 5 to rotate.

[0028] The transmission mechanism 4 includes a planetary gear mechanism 41, a drive shaft 42, a return spring 43, two first spherical bodies 44 (steel balls), two second spherical bodies 45 (steel balls), and a ring 46.

[0029] The planetary gear mechanism 41 converts the rotation speed and torque of the rotating shaft 311 of the motor 3 into a predetermined rotation speed and a predetermined torque. The planetary gear mechanism 41 is a reduction gear. The torque of the rotating shaft 311 of the motor 3 is transmitted to the drive shaft 42 via the planetary gear mechanism 41. The torque of the drive shaft 42 is transmitted to the hammer 5. This causes the hammer 5 to rotate.

[0030] The return spring 43 in this embodiment is a conical coil spring. The return spring 43 applies a force pushing the hammer 5 forward. A ring 46 is disposed between the return spring 43 and the hammer 5. Two second spherical bodies 45 are sandwiched between the ring 46 and the hammer 5. This allows the hammer 5 to rotate with respect to the return spring 43.

[0031] (5) Hammer, anvil and output shaft The rotary impact tool 1 of this embodiment is an electric impact driver that performs an impact operation while tightening a screw. In the impact operation, a striking force is applied from a hammer 5 to an anvil 6, and the striking force is transmitted to a tool tip via an output shaft 7.

[0032] As shown in Fig. 3 to Fig. 5, the hammer 5 includes a hammer body 51 and two hammer claws 52. The hammer body 51 has a cylindrical shape. The two hammer claws 52 protrude forward from the hammer body 51. The hammer body 51 has a through hole 510 through which the drive shaft 42 passes.

[0033] The hammer body 51 has two grooves 511 on the inner peripheral surface of the through hole 510. As shown in FIG. 2, the drive shaft 42 has two grooves 421 on its outer peripheral surface. The two grooves 421 are connected to each other. Between each groove 511 and the corresponding groove 421, a corresponding first spherical body 44 is sandwiched. The grooves 511, 421, and the first spherical body 44 form a cam mechanism. While the first spherical body 44 moves in the grooves 511 and 413, the hammer 5 can move in the axial direction (front-rear direction) of the drive shaft 42 relative to the drive shaft 42 and can rotate relative to the drive shaft 42. As the hammer 5 moves forward or backward along the axial direction of the drive shaft 42, the hammer 5 rotates relative to the drive shaft 42.

[0034] The anvil 6 faces the hammer body 51 in the front-rear direction. As shown in Figs. 3 to 5, the anvil 6 includes an anvil body 61, two anvil claws 62, and two first contact portions 63. The anvil body 61 is cylindrical in shape. The two anvil claws 62 protrude from the anvil body 61 in the radial direction of the anvil body 61. The two first contact portions 63 protrude forward from the anvil body 61. In other words, the two first contact portions 63 protrude from the anvil body 61 in the thrust direction. The two first contact portions 63 are aligned in the rotational direction of the anvil 6.

[0035] The anvil body 61 has a first recess 611 on its rear surface into which the tip end of the drive shaft 42 is inserted. The anvil body 61 also has a second recess 612 on its front surface into which the buffer member 8 is inserted.

[0036] When the hammer 5 rotates, the two hammer claws 52 push the two anvil claws 62 in the rotational direction of the hammer 5, causing the anvil 6 to rotate.

[0037] As shown in FIGS. 4 and 7, the anvil 6 has a first contact surface C1 and a first opposing region F1.

[0038] The first contact surface C1 is a surface that comes into contact with a second contact surface C2 (described later) of the output shaft 7. The first contact surface C1 faces and comes into contact with the second contact surface C2 in the rotational direction of the anvil 6. The first contact surface C1 is a surface of the two first contact portions 63 and is a surface along the front-rear direction.

[0039] The first opposing region F1 is an area facing a second opposing region F2 (described later) of the output shaft 7. A part of the first opposing region F1 is an area of ​​the front surface of the anvil body 61 excluding an area where the two first contact portions 63 are provided. Another part of the first opposing region F1 is the front surface of each of the two first contact portions 63.

[0040] The output shaft 7 includes an output shaft body 71 and two second contact portions 72. The output shaft body 71 is cylindrical in shape. The output shaft body 71 is passed through a through hole 2110 (see FIG. 1) of the housing 2, and a front end of the output shaft body 71 is exposed to the outside of the housing 2. The output shaft body 71 has a recess 711 on its rear surface into which the buffer member 8 is inserted. The two second contact portions 72 protrude rearward from the output shaft body 71. That is, the two second contact portions 72 protrude from the output shaft body 71 in the thrust direction. The two second contact portions 72 are aligned in the rotation direction of the output shaft 7.

[0041] As shown in FIGS. 5 and 7, the output shaft 7 has a second contact surface C2 and a second opposing region F2.

[0042] The second contact surface C2 is a surface that comes into contact with the first contact surface C1 of the anvil 6. The second contact surface C2 faces and comes into contact with the first contact surface C1 in the rotation direction of the anvil 6. The output shaft 7 receives the rotational force of the anvil 6 at the second contact surface C2 and rotates. The second contact surface C2 is a surface of the two second contact portions 72 and is a surface along the front-rear direction.

[0043] The second opposing region F2 is an area facing the first opposing region F1 of the anvil 6. A part of the second opposing region F2 is an area of ​​the rear surface of the output shaft body 71 excluding the area where the two second contact portions 72 are provided. Another part of the second opposing region F2 is the rear surface of each of the two second contact portions 72.

[0044] Thus, the output shaft 7 includes the output shaft body 71 and the two second contact portions 72, and the two second contact portions 72 protrude in the thrust direction from the output shaft body 71. The two second contact portions 72 come into contact with the two first contact portions 63. The two second contact portions 72 receive a force that rotates the output shaft 7 from the two first contact portions 63.

[0045] The output shaft 7 holds the tool bit. More specifically, the tool bit is detachably attached to the output shaft 7. In this embodiment, the tool bit is connected to the output shaft 7 via a chuck. The output shaft 7 receives torque from the motor 3 and rotates together with the chuck and the tool bit.

[0046] When the anvil 6 rotates, the two first contact portions 63 of the anvil 6 push the two second contact portions 72 of the output shaft 7 in the rotational direction of the anvil 6, causing the output shaft 7 to rotate. The output shaft 7 rotates at the same rotation speed as the anvil 6.

[0047] The rotation direction of the anvil 6 coincides with the rotation direction of the hammer 5. As shown in Fig. 6, the anvil 6 and the output shaft 7 are configured so that the concave-convex formed by the two first contact portions 63 and the concave-convex formed by the two second contact portions 72 mesh with each other.

[0048] The chuck and the tool tip are not components of the impact rotary tool 1. However, the impact rotary tool 1 may include at least one of the chuck and the tool tip. Also, the tool tip may be directly connected to the output shaft 7 without using the chuck.

[0049] The tool tip is, for example, a driver bit. The tool tip is engaged with a screw (such as a bolt or a screw) to be worked on. When the tool tip is rotated while engaged with the screw, it becomes possible to perform work such as tightening or loosening the screw.

[0050] When the rotary impact tool 1 is not performing an impact operation, the hammer 5 and the anvil 6 rotate at the same rotation speed while the two hammer claws 52 and the two anvil claws 62 are in contact with each other in the rotation direction of the hammer 5. Therefore, at this time, the drive shaft 42, the hammer 5, the anvil 6, and the output shaft 7 rotate at the same rotation speed.

[0051] The impact rotary tool 1 performs an impact operation when a torque condition regarding the magnitude of the torque (hereinafter referred to as load torque) applied to the output shaft 7 is satisfied. The impact operation is an operation in which a striking force is applied from the hammer 5 to the anvil 6. In this embodiment, the torque condition is that the load torque is equal to or greater than a predetermined value. That is, when the load torque increases, the component of the force generated between the hammer 5 and the anvil 6 in the direction in which the hammer 5 retreats also increases. When the load torque exceeds a predetermined value, the hammer 5 retreats while compressing the return spring 43. Then, as the hammer 5 retreats, the two hammer claws 52 of the hammer 5 climb over the two anvil claws 62 of the anvil 6, and the hammer 5 rotates. Thereafter, the hammer 5 advances by receiving the return force from the return spring 43. Then, when the drive shaft 42 rotates approximately half a turn, the two hammer claws 52 of the hammer 5 collide with the side surfaces 620 (see FIG. 3) of the two anvil claws 62 of the anvil 6. The two hammer claws 52 of the hammer 5 collide with the two anvil claws 62 of the anvil 6 every time the drive shaft 42 makes approximately a half rotation. In other words, the hammer 5 applies a striking force to the anvil 6 every time the drive shaft 42 makes approximately a half rotation.

[0052] In this way, in the rotary impact tool 1, collisions between the hammer 5 and the anvil 6 occur repeatedly. Due to the torque caused by these collisions, it is possible to tighten the screw more strongly than in the case where there is no collision.

[0053] (6) Cushioning materials 4 and 7, the cushioning member 8 includes an elastic member 81 and an adjustment member 82. The elastic member 81 and the adjustment member 82 are each, for example, cylindrical in shape.

[0054] The elastic member 81 is an elastic body such as rubber, etc. The elastic member 81 is elastically deformed in the thrust direction (front-rear direction).

[0055] The adjustment member 82 is formed, for example, from a metal material. The adjustment member 82 is formed separately from the anvil 6 and the output shaft 7.

[0056] The elastic modulus of the adjustment member 82 in the thrust direction is greater than the elastic modulus of the elastic member 81. The elastic member 81 and the adjustment member 82 are aligned in the thrust direction.

[0057] The buffer member 8 is sandwiched between the anvil 6 and the output shaft 7. More specifically, the adjustment member 82 is inserted into the second recess 612 of the anvil 6, and the elastic member 81 is inserted into the recess 711 of the output shaft 7. The elastic member 81 is sandwiched between the adjustment member 82 and the output shaft 7. The adjustment member 82 is sandwiched between the elastic member 81 and the anvil 6.

[0058] The buffer member 8 is sandwiched between the anvil 6 and the output shaft 7, thereby regulating the distance between the anvil 6 and the output shaft 7. In other words, since the buffer member 8 is sandwiched between the anvil 6 and the output shaft 7, the distance between the anvil 6 and the output shaft 7 is determined by the length of the buffer member 8 in the thrust direction.

[0059] The buffer member 8 is disposed on the central axis of the output shaft 7. Therefore, the stress acting on the anvil 6 and the output shaft 7 is likely to be distributed isotropically around the central axis of the output shaft 7. In other words, stress concentration on the anvil 6 and the output shaft 7 can be suppressed.

[0060] The force acting on the anvil 6 from the hammer 5 may include a forward component. Therefore, the anvil 6 may advance toward the output shaft 7 while compressing the elastic member 81 due to the force received from the hammer 5. FIG. 7 shows the positional relationship between the anvil 6 and the output shaft 7 in a state where no forward force is acting on the anvil 6 from the hammer 5. FIG. 8 shows the positional relationship between the anvil 6 and the output shaft 7 in a state where a forward force is acting on the anvil 6 from the hammer 5. As the anvil 6 advances, the length of the elastic member 81 in the front-rear direction is shortened from length L1 to length L11. In addition, as the anvil 6 advances, the length of the gap between the first facing region F1 and the second facing region F2 is shortened from length W1, W2 to length W11, W12. The lengths W1 and W11 are the lengths of the gaps between the anvil body 61 and the two second contact portions 72, and the lengths W2 and W12 are the lengths of the gaps between the output shaft body 71 and the two first contact portions 63.

[0061] (7) First bearing and second bearing 2, the first bearing 91 is held in the housing 2. More specifically, the first bearing 91 is held in the first accommodating portion 211. The first bearing 91 is in contact with the two first contact portions 63 and the two second contact portions 72, and rotatably supports the anvil 6 and the output shaft 7.

[0062] The first bearing 91 is, for example, a needle bearing. By using a needle bearing for the first bearing 91, it is possible to reduce the possibility that vibrations in the thrust direction of the anvil 6 and the output shaft 7 are directly transmitted to the first bearing 91. This reduces the possibility that a load in the thrust direction is concentrated near the contact point between the anvil 6 and the output shaft 7 and the first bearing 91, and it is possible to improve the durability of the anvil 6 and the output shaft 7.

[0063] The first bearing 91 has an external shape of a circular ring (see FIG. 4). The first bearing 91 surrounds the two first contact portions 63 of the anvil 6 and the two second contact portions 72 of the output shaft 7. More specifically, the first bearing 91 surrounds the two first contact portions 63 from their front ends to their rear ends. The first bearing 91 also surrounds the two second contact portions 72 from their front ends to their rear ends.

[0064] The first bearing 91 is in contact with the two first contact portions 63 of the anvil 6 and the anvil body 61 to rotatably support the anvil 6 .

[0065] The first bearing 91 is in contact with the two second contact portions 72 of the output shaft 7 and the output shaft body 71 to rotatably support the output shaft 7.

[0066] The second bearing 92 is disposed forward of the first bearing 91. The second bearing 92 is held by the housing 2. More specifically, the second bearing 92 is held in the first accommodating portion 211. The second bearing 92 supports the output shaft 7 so as to be rotatable.

[0067] The second bearing 92 is, for example, a ball bearing. The outer shape of the second bearing 92 is annular (see FIG. 4).

[0068] The second bearing 92 is in contact with the output shaft body 71 to rotatably support the output shaft 7. By providing the second bearing 92, the possibility of the output shaft 7 wobbling can be reduced.

[0069] Further, in order to suppress rattling of the first bearing 91 and the second bearing 92 in the front-rear direction, a first stopper 93 and a second stopper 94 are provided (see FIGS. 2 and 4).

[0070] The first stopper 93 has an annular shape. The first stopper 93 is disposed behind the first bearing 91. The first stopper 93 faces the first bearing 91.

[0071] The second stopper 94 has an annular shape. The second stopper 94 is disposed in front of the first bearing 91. More specifically, the second stopper 94 is disposed between the first bearing 91 and the second bearing 92. The second stopper 94 faces the first bearing 91 and the second bearing 92.

[0072] When the first bearing 91 attempts to move in the front-rear direction, it comes into contact with the first stopper 93 or the second stopper 94, thereby restricting the movement of the first bearing 91. In addition, when the second bearing 92 attempts to move rearward, it comes into contact with the second stopper 94, thereby restricting the movement of the second bearing 92.

[0073] (8) Compression amount of elastic body As described above, when a forward force is applied from the hammer 5 to the anvil 6, the anvil 6 may move forward so as to approach the output shaft 7 while compressing the elastic member 81, as shown in FIG. 8. Here, if the anvil 6 collides with the output shaft 7 and vibration occurs, a collision sound may be generated from the anvil 6 and the output shaft 7, or the vibration may be transmitted to the housing 2 and sound may be generated from the entire housing 2, which is undesirable. In addition, if the housing 2 vibrates, the vibration may be transmitted to the worker holding the housing 2, which may hinder the comfort of the work. Therefore, in the impact rotary tool 1 of this embodiment, the parameters of the buffer member 8 are designed so as to reduce the possibility that the anvil 6 will collide with the output shaft 7. The parameters of the buffer member 8 are, for example, the lengths of the elastic member 81 and the adjustment member 82 in the thrust direction, and the elastic modulus of the elastic member 81 in the thrust direction.

[0074] Specifically, the parameters of the buffer member 8 are designed so that the second opposing region F2 faces the first opposing region F1 with a gap in the thrust direction when the maximum load transmitted from the hammer 5 is applied to the elastic member 81. The magnitude of the maximum load transmitted from the hammer 5 to the elastic member 81 depends on the shape and elastic modulus of the return spring 43, the rotation speed of the motor 3, etc.

[0075] It is sufficient that the compression amount P, which is defined below, is smaller than the distance (lengths W1, W2) in the thrust direction between the first opposing region F1 and the second opposing region F2 when a load of a predetermined magnitude smaller than the maximum load is applied to the elastic member 81. The compression amount P is the amount obtained by subtracting the length L11 (see FIG. 8) of the elastic member 81 in the thrust direction when the maximum load is applied to the elastic member 81 from the length L1 (see FIG. 7) of the elastic member 81 in the thrust direction when the load of the predetermined magnitude is applied to the elastic member 81. This can reduce the possibility of the anvil 6 and the output shaft 7 colliding when the maximum load is applied to the elastic member 81.

[0076] The predetermined magnitude may be 0. In other words, when a load of a predetermined magnitude is applied to the elastic member 81, the elastic member 81 may be in an unloaded state.

[0077] Further, a load may be applied to the elastic member 81 not only from the hammer 5 but also from the output shaft 7. Therefore, a load larger than the maximum load transmitted from the hammer 5 to the elastic member 81 may be applied to the elastic member 81. Even in such a case, it is preferable that the first opposing region F1 and the second opposing region F2 face each other with a gap therebetween in the thrust direction.

[0078] Therefore, the parameters of the buffer member 8 may be designed so that the second opposing region F2 faces the first opposing region F1 with a gap in the thrust direction when a load equal to or less than the upper limit of the elastic region of the elastic member 81 is applied to the elastic member 81. Also, for example, the parameters of the buffer member 8 may be designed so that the second opposing region F2 faces the first opposing region F1 with a gap in the thrust direction when a load equal to or less than a predetermined multiple (the predetermined multiple is less than 1, for example, 0.9) of the upper limit of the elastic region of the elastic member 81 is applied to the elastic member 81.

[0079] Moreover, the cushioning member 8 of this embodiment includes an adjustment member 82 in addition to the elastic member 81. The adjustment member 82 has a higher elastic modulus than the elastic member 81. More specifically, the adjustment member 82 is hardly compressed and deformed.

[0080] The elastic member 81 and the adjustment member 82 are aligned in the thrust direction. Therefore, the length of the elastic member 81 in the thrust direction can be shortened by the length of the adjustment member 82, compared to a case in which the buffer member 8 includes only the elastic member 81.

[0081] The shorter the elastic member 81 is in the thrust direction, the less likely the elastic member 81 is to deform. In other words, the shorter the elastic member 81 is in the thrust direction, the smaller the amount of compression of the elastic member 81 when a force of a predetermined magnitude in the thrust direction is applied to the elastic member 81. Therefore, the shorter the elastic member 81 is in the thrust direction, the smaller the amount of change in the distance (lengths of the gap W1, W2) between the first opposing region F1 and the second opposing region F2 caused by the force in the thrust direction being applied to the elastic member 81. Therefore, the distance between the first opposing region F1 and the second opposing region F2 when a force of a predetermined magnitude in the thrust direction is not applied to the elastic member 81 can be made shorter, and the length from the rear end of the anvil 6 to the front end of the output shaft 7 can be made shorter. Therefore, the impact rotary tool 1 can be made smaller in size.

[0082] (9) Reinforcement by the first bearing The first bearing 91 of this embodiment is in contact with the first contact portion 63 of the anvil 6 and the second contact portion 72 of the output shaft 7, and rotatably supports the anvil 6 and the output shaft 7. The first contact portion 63 and the second contact portion 72 are in contact with the first bearing 91, thereby reinforcing their mechanical strength. In particular, the first contact portion 63 and the second contact portion 72 are reinforcing their mechanical strength against vibration in the radial direction of the output shaft 7. This improves the durability of the anvil 6 and the output shaft 7.

[0083] In addition, in the configuration of the anvil 6, the first contact portion 63 has a lower rigidity than the anvil body 61, and in the configuration of the output shaft 7, the second contact portion 72 has a lower rigidity than the output shaft body 71. By reinforcing such first contact portion 63 and second contact portion 72, the life span of the anvil 6 and the output shaft 7 can be extended.

[0084] (Variation 1) Hereinafter, the impact rotary tool 1 according to the first modification will be described with reference to Fig. 9. The same components as those in the embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

[0085] The rotary impact tool 1 of the present modified example 1 includes, instead of the anvil 6, the output shaft 7, and the buffer member 8, an anvil 6A, an output shaft 7A, and a buffer member 8A.

[0086] The anvil 6A includes an anvil body 61, two anvil claws 62, and a first contact portion 63. The anvil body 61 is cylindrical in shape. The two anvil claws 62 protrude from the anvil body 61 in the radial direction of the anvil body 61. The first contact portion 63 is cylindrical in shape. The first contact portion 63 protrudes forward from the anvil body 61.

[0087] The first contact portion 63 has a recess 630 on its front surface into which the second contact portion 72 of the output shaft 7A and the buffer member 8A are inserted. The area of ​​the front surface of the first contact portion 63 excluding the recess 630 is a first opposing area F1 opposing the output shaft 7A.

[0088] The output shaft 7A includes an output shaft body 71 and a second contact portion 72. The output shaft body 71 is cylindrical in shape. The second contact portion 72 is columnar in shape. The second contact portion 72 protrudes rearward from the output shaft body 71. The rear surface of the output shaft body 71, except for the area where the second contact portion 72 is provided, is a second opposing region F2 that faces the first opposing region F1. A gap is provided between the first opposing region F1 and the second opposing region F2 in the front-rear direction.

[0089] The shape of the second contact portion 72 follows the shape of the recess 630 of the first contact portion 63. More specifically, the shape of the second contact portion 72 is square when viewed from the rear. The shape of the recess 630 is square when viewed from the front. An outer surface (second contact surface C2) of the second contact portion 72 along the front-rear direction contacts an inner surface (first contact surface C1) of the recess 630 along the front-rear direction. This transmits the rotation of the anvil 6A to the output shaft 7A.

[0090] The cushioning member 8A includes an elastic member 81 and an adjustment member 82 arranged in the front-rear direction. The cushioning member 8A is sandwiched between the second contact portion 72 and the bottom surface of the recessed portion 630.

[0091] Further, the first bearing 91 (see FIG. 2) is in contact with the first contact portion 63, and rotatably supports the anvil 6A. The output shaft 7A is supported by the first bearing 91 via the anvil 6A.

[0092] In this modified example 1 as well, the distance between the first opposing area F1 of the anvil 6A and the second opposing area F2 of the output shaft 7A can be regulated by the buffer member 8A. Also, in this modified example 1 as well, the anvil 6A and the output shaft 7A can be reinforced by the first bearing 91.

[0093] In the present modified example 1, the second contact portion 72 is inserted into the recess 630 provided in the first contact portion 63. Conversely, the first contact portion 63 may be inserted into the recess provided in the second contact portion 72.

[0094] As a further modification 2 of the present modification 1, the second contact portion 72 may be formed in a spline shape as shown in Fig. 10. That is, a plurality of teeth may be provided on the outer circumferential surface of the second contact portion 72. Then, a plurality of teeth that mesh with the plurality of teeth of the second contact portion 72 may be provided on the inner surface of the first contact portion 63.

[0095] The shapes of the anvil 6A and the output shaft 7A in the first and second modifications are different from those of the anvil 6 and the output shaft 7 in the embodiment. Therefore, in order to transmit a torque equivalent to that transmitted from the anvil 6 to the output shaft 7 in the embodiment from the anvil 6A in the first modification to the output shaft 7A, it is necessary to make the diameters of the anvil 6A and the output shaft 7A larger than those in the embodiment. On the other hand, by using a configuration in which the multiple first contact portions 63 are aligned in the rotation direction of the anvil 6 and the multiple second contact portions 72 are aligned in the rotation direction of the output shaft 7 as in the embodiment, the anvil 6 and the output shaft 7 can be made smaller in size.

[0096] (Other Modifications of the Embodiments) Other variations of the embodiment are listed below. The following variations may be implemented in appropriate combination. The following variations may also be implemented in appropriate combination with the above-mentioned variations.

[0097] The number of hammer claws 52 and the number of anvil claws 62 are not limited to two, and may be one or three or more.

[0098] The number of the first contact portions 63 of the anvil 6 and the number of the second contact portions 72 of the output shaft 7 are not limited to two, and may be one or three or more.

[0099] Each of the first facing region F1 and the second facing region F2 is not limited to a flat surface, and may be a curved surface.

[0100] In the embodiment, the elastic member 81 is located in front of the adjustment member 82. Alternatively, the adjustment member 82 may be located in front of the elastic member 81.

[0101] The cushioning member 8 may include a plurality of elastic members 81 .

[0102] The buffer member 8 may include a plurality of adjustment members 82 .

[0103] In the embodiment, the first bearing 91 surrounds the first contact portion 63 of the anvil 6. Alternatively, the first bearing 91 may surround only a portion of the first contact portion 63.

[0104] In the embodiment, the first bearing 91 surrounds the second contact portion 72 of the output shaft 7. Alternatively, the first bearing 91 may surround a portion of the second contact portion 72.

[0105] It is not essential that the first bearing 91 contacts the anvil body 61 .

[0106] It is not essential that the first bearing 91 contacts the output shaft body 71 .

[0107] The first bearing 91 is not limited to a needle bearing, and may be, for example, a bushing, a ball bearing, or a double row angular contact ball bearing.

[0108] The second bearing 92 is not limited to a ball bearing, and may be, for example, a bushing, a needle bearing, or a double row angular contact ball bearing.

[0109] The adjustment member 82 may be formed integrally with the anvil 6 or the output shaft 7. However, it is preferable that the adjustment member 82 is separate from the anvil 6, since this can suppress stress concentration in the anvil 6. It is also preferable that the adjustment member 82 is separate from the output shaft 7, since this can suppress stress concentration in the output shaft 7.

[0110] The elastic member 81 and the adjustment member 82 may be bonded to each other by adhesion or the like.

[0111] The magnitude of the maximum load transmitted from the hammer 5 to the elastic member 81 may be defined as being equal to the maximum spring force acting on the hammer 5 from the return spring 43 .

[0112] (summary) The above-described embodiments and the like disclose the following aspects.

[0113] The impact rotary tool (1) according to the first embodiment includes a hammer (5), an anvil (6, 6A), an output shaft (7, 7A), a housing (2), a bearing (first bearing 91), and a buffer member (8, 8A). The hammer (5) receives power from a motor (3) and rotates. The anvil (6, 6A) receives a striking force from the hammer (5) in the rotational direction of the hammer (5) and rotates. The output shaft (7, 7A) is configured to hold a tool tip, and receives a force from the anvil (6, 6A) in the rotational direction of the anvil (6, 6A) and rotates together with the anvil (6, 6A). The housing (2) accommodates the hammer (5) and the anvil (6, 6A). The bearing (first bearing 91) is held by the housing (2) and rotatably supports the output shaft (7, 7A). The buffer member (8, 8A) includes an elastic member (81) that elastically deforms in a thrust direction, which is a direction along the rotation axis of the output shaft (7, 7A). The anvil (6, 6A) has a first opposing region (F1) that faces the output shaft (7, 7A) in the thrust direction. The output shaft (7, 7A) has a second opposing region (F2) that faces the first opposing region (F1) in the thrust direction. The buffer member (8, 8A) is sandwiched between the anvil (6, 6A) and the output shaft (7, 7A). The elastic member (81) is compressed in the thrust direction by the load in the thrust direction transmitted from the hammer (5). When the elastic member (81) is subjected to the maximum load transmitted from the hammer (5), the buffer member (8, 8A) regulates the distance between the second opposing region (F2) and the first opposing region (F1) so that the second opposing region (F2) faces the first opposing region (F1) with a gap in the thrust direction.

[0114] According to the above configuration, the possibility of the anvil (6, 6A) colliding with the output shaft (7, 7A) can be reduced, thereby reducing the possibility of the occurrence of collision noise and the transmission of vibrations due to the collision to the housing (2).

[0115] In the first aspect of the impact rotating tool (1) according to the second aspect, the anvil (6, 6A) includes an anvil body (61) and a first contact portion (63) protruding from the anvil body (61) in a thrust direction. The output shaft (7, 7A) includes an output shaft body (71) and a second contact portion (72) protruding from the output shaft body (71) in the thrust direction. The second contact portion (72) comes into contact with the first contact portion (63). The second contact portion (72) receives a force from the first contact portion (63) that rotates the output shaft (7, 7A).

[0116] According to the above configuration, the anvil (6, 6A) and the output shaft (7, 7A) are brought into contact with each other at the first contact portion (63) protruding from the anvil body (61) and the second contact portion (72) protruding from the output shaft body (71), thereby improving the efficiency of torque transmission from the anvil (6, 6A) to the output shaft (7, 7A).

[0117] In the rotary impact tool (1) according to the third aspect, in the second aspect, the anvil (6) includes a plurality of first contact portions (63). The plurality of first contact portions (63) are aligned in the rotational direction of the anvil (6). The output shaft (7) includes a plurality of second contact portions (72), and the plurality of second contact portions (72) are aligned in the rotational direction of the output shaft (7).

[0118] According to the above configuration, the efficiency of torque transmission from the anvil (6) to the output shaft (7) can be further improved.

[0119] In the rotary impact tool (1) according to a fourth aspect, in any one of the first to third aspects, the buffer member (8, 8A) is disposed on the central axis of the output shaft (7, 7A).

[0120] According to the above configuration, the stress acting on the anvil (6, 6A) and the output shaft (7, 7A) is likely to be distributed isotropically around the central axis of the output shaft (7, 7A), which means that stress concentration on the anvil (6, 6A) and the output shaft (7, 7A) can be suppressed.

[0121] In addition, in the impact rotary tool (1) according to a fifth aspect, in any one of the first to fourth aspects, the buffer member (8, 8A) further includes an adjustment member (82) having a higher elastic modulus in the thrust direction than the elastic member (81). The elastic member (81) and the adjustment member (82) are aligned in the thrust direction.

[0122] According to the above-described configuration, the length of the elastic member (81) in the thrust direction can be shortened by the length of the adjustment member (82).

[0123] In the rotary impact tool (1) according to the sixth aspect, in the fifth aspect, the adjustment member (82) is formed separately from the anvil (6, 6A) and the output shaft (7, 7A).

[0124] According to the above configuration, stress concentration on the anvil (6, 6A) can be reduced compared to when the adjustment member (82) is integrated with the anvil (6, 6A). Also, stress concentration on the output shaft (7, 7A) can be reduced compared to when the adjustment member (82) is integrated with the output shaft (7, 7A).

[0125] The configurations other than those of the first aspect are not essential to the impact rotary tool (1) and may be omitted as appropriate. [Explanation of symbols]

[0126] 1. Impact rotary tool 2. Housing 3 Motor 5 Hammer 6, 6A Anvil 7, 7A output shaft 8, 8A Cushioning material 61 Anvil body 63 1st contact part 71 Output shaft body 72 Second contact part 81 Elastic member 82 Adjustment parts 91 No. 1 bearing (bearing) F1 1st opposing area F2 2nd opposing area

Claims

1. A hammer that rotates by receiving power from a motor, an anvil that rotates by receiving a striking force from the hammer in a rotational direction of the hammer; an output shaft configured to hold a tool bit and rotate together with the anvil by receiving a force from the anvil in a rotational direction of the anvil; a housing that accommodates the hammer and the anvil; a bearing held by the housing and rotatably supporting the output shaft; a buffer member including an elastic member that is elastically deformed in a thrust direction that is a direction along the rotation axis of the output shaft, the anvil has a first opposing region opposing the output shaft in the thrust direction, the output shaft has a second opposing region opposed to the first opposing region in the thrust direction, The buffer member is sandwiched between the anvil and the output shaft, the elastic member is compressed in the thrust direction by a load in the thrust direction transmitted from the hammer, the buffer member regulates a distance between the second opposing region and the first opposing region such that the second opposing region faces the first opposing region with a gap therebetween in the thrust direction when a maximum load transmitted from the hammer is applied to the elastic member; The bearing is in contact with the output shaft and the anvil. Impact rotary tool.

2. The anvil includes an anvil body and a first contact portion protruding from the anvil body in the thrust direction, The output shaft includes an output shaft main body and a second contact portion that protrudes from the output shaft main body in the thrust direction and contacts the first contact portion to receive a force that rotates the output shaft from the first contact portion. The rotary impact tool according to claim 1.

3. The anvil includes a plurality of the first contact portions, and the plurality of first contact portions are aligned in the rotation direction of the anvil, The output shaft includes a plurality of the second contact portions, and the plurality of second contact portions are aligned in a rotation direction of the output shaft. The rotary impact tool according to claim 2.

4. The buffer member is disposed on the central axis of the output shaft. The rotary impact tool according to any one of claims 1 to 3.

5. The buffer member further includes an adjustment member having a larger elastic modulus in the thrust direction than the elastic member, The elastic member and the adjustment member are aligned in the thrust direction. The rotary impact tool according to any one of claims 1 to 3.

6. The adjustment member is formed separately from the anvil and the output shaft. The rotary impact tool according to claim 5.

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