Impact rotary tools

Abstract

To provide an impact rotary tool that can reduce impact noise. [Solution] The impact rotary tool comprises a motor 10, an output shaft 30, an impact mechanism 4, an inner cover 3, and a main body case. A cutting tool can be attached to the output shaft 30. The impact mechanism 4 applies impact force to the output shaft 30 in accordance with the rotation of the motor 10. The main body case houses the motor 10, the impact mechanism 4, and the inner cover 3. The impact mechanism 4 has hammer members 40A and 40B that strike the impact targets 32 and 33 provided on the output shaft 30 in accordance with the rotation of the motor 10. The inner cover 3 covers at least the impact mechanism 4.

Description

Technical Field

[0001] The present disclosure relates to an impact rotary tool. More specifically, the present disclosure relates to an impact rotary tool that rotates an output shaft by applying an impact force.

Background Art

[0002] Patent Document 1 discloses an impact wrench. The impact wrench of Patent Document 1 includes a columnar spindle rotated by a motor, an anvil, a main hammer, a sub-hammer, and a rotary impact mechanism.

[0003] The anvil is disposed in front of the spindle in the axial direction of rotation, has a hole in the front part into which a driver bit is inserted, and has a first claw provided at the rear part. The main hammer is fitted on the outer periphery of the spindle and has a second claw provided at the front part that engages with the first claw. The main hammer is rotatable about the axis of rotation of the spindle and movable in the axial direction. The sub-hammer has a cylindrical portion that rotates integrally with the main hammer, and the spindle is inserted through the internal space of the cylindrical portion and the main hammer is accommodated therein.

[0004] The rotary impact mechanism is interposed between the spindle and the main hammer. When a torque exceeding a predetermined value acts between the spindle and the main hammer, the main hammer is rotated and advanced in the direction of the anvil, and the second claw is impactingly engaged with the first claw to strike the first claw, thereby rotating the anvil about its axis.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The purpose of this disclosure is to provide an impact rotary tool capable of reducing impact noise. [Means for solving the problem]

[0007] An impact rotary tool according to one aspect of the present disclosure comprises a motor, an output shaft to which a tool tip can be attached, an impact mechanism, an inner cover, and a main body case. The impact mechanism applies an impact force to the output shaft in accordance with the rotation of the motor. The main body case houses the motor, the impact mechanism, and the inner cover. The impact mechanism has a hammer member that strikes a part to be struck on the output shaft in accordance with the rotation of the motor. The inner cover covers at least the impact mechanism. [Effects of the Invention]

[0008] The purpose of this disclosure is to provide an impact rotary tool capable of reducing impact noise. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an exploded perspective view of the main components of an impact rotary tool according to one embodiment of the present disclosure. [Figure 2] Figure 2 is an exploded perspective view of the same impact rotary tool. [Figure 3] Figure 3 is a side view of the same impact rotary tool. [Figure 4] Figure 4 is a cross-sectional view taken along line A1-A2 in Figure 3. [Figure 5] Figure 5 is a cross-sectional view of the line B1-B2 in Figure 3. [Figure 6] Figure 6 is an exploded perspective view of the main part of an impact rotary tool according to Modification 1 of one embodiment of the present disclosure. [Figure 7] Figure 7 is an exploded perspective view of the impact rotary tool of Modification 1. [Figure 8] Figure 8 is a perspective view of the screw-fixed inner cover section of the impact rotary tool of Modification 2. [Figure 9]FIG. 9 is a cross-sectional view of the screw-fixed middle cover portion provided in the impact rotary tool of Modification 2. [Figure 10] FIG. 10 is a perspective view of the retaining ring-fixed middle cover portion provided in the impact rotary tool of Modification 2. [Figure 11] FIG. 11 is a cross-sectional view of the retaining ring-fixed middle cover portion provided in the impact rotary tool of Modification 2. [Figure 12] FIG. 12 is a perspective view of the case screw-fixed middle cover portion provided in the impact rotary tool of Modification 2. [Figure 13] FIG. 13 is a cross-sectional view of the case screw-fixed middle cover portion provided in the impact rotary tool of Modification 2. [Figure 14] FIG. 14 is an exploded perspective view of the case screw-fixed middle cover portion provided in the impact rotary tool of Modification 2. [Figure 15] FIG. 15 is a perspective view of the hammer member provided in the impact rotary tool of Modification 3. [Figure 16] FIG. 16 is a cross-sectional view of a main part of the impact rotary tool of Modification 4.

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, the impact rotary tool according to the embodiment will be described in detail with reference to the drawings. However, each of the drawings described in the following embodiments is a schematic diagram, and the dimensional ratios such as the sizes of the respective components do not necessarily reflect the actual dimensional ratios. Further, the configurations described in the following embodiments are merely examples of the present disclosure. The present disclosure is not limited to the following embodiments, and various modifications can be made according to the design and the like as long as the effects of the present disclosure can be achieved.

[0011] (Embodiment) (1) Outline FIG. 1 is an exploded perspective view of a main part of the impact rotary tool 1 of the present embodiment. FIG. 2 is an exploded perspective view of the impact rotary tool 1. FIG. 3 is a side view of the impact rotary tool 1.

[0012] The impact rotary tool 1 of the present embodiment includes a motor 10, an output shaft 30, an impact mechanism 4, a middle cover portion 3, and a main body case 2.

[0013] A tip tool T1 can be attached to the output shaft 30.

[0014] The impact mechanism 4 applies an impact force to the output shaft 30 in accordance with the rotation of the motor 10.

[0015] The main body case 2 houses the motor 10, the impact mechanism 4, and the middle cover portion 3.

[0016] The impact mechanism 4 has hammer members 40A and 40B that strike struck portions 32 and 33 provided on the output shaft 30 in accordance with the rotation of the motor 10.

[0017] The middle cover portion 3 covers at least the impact mechanism 4.

[0018] Here, the attachment of the tip tool T1 to the output shaft 30 means that the tip tool T1 may be directly attached to the output shaft 30, or the tip tool T1 may be attached to the output shaft 30 via another member. In FIG. 3, the illustration of the tip tool T1 is omitted, and the tip tool T1 is shown by a two-dot chain line.

[0019] In the impact rotary tool 1 of this embodiment, the inner cover portion 3 housed in the main body case 2 covers the impact mechanism 4, so the impact mechanism 4 can be double-covered by the inner cover portion 3 and the main body case 2. Therefore, when impact noise is generated when the hammer members 40A and 40B strike the parts to be struck 32 and 33, the impact noise transmitted to the outside of the main body case 2 can be reduced. Also, if the inner cover portion 3 is filled with lubricant for lubricating the impact mechanism 4, the inner cover portion 3 can suppress the scattering of lubricant, so the lubrication effect of the lubricant is less likely to decrease, and wear of the parts constituting the impact mechanism 4 can be suppressed. Furthermore, the impact rotary tool 1 of this embodiment does not have a reduction mechanism that reduces the rotation of the rotating shaft 11 of the motor 10 and transmits it to the output shaft 30, so it also has the advantage of reducing the reaction force generated when the hammer members 40A and 40B strike the parts to be struck 32 and 33.

[0020] (2) Details The impact rotary tool 1 according to this embodiment will be described in detail below with reference to Figures 1 to 5, etc. In the following description, the X-axis direction (the direction in which the output shaft 30 protrudes from the main body case 2) is defined as the front-to-back direction, the Y-axis direction as the left-to-right direction, and the Z-axis direction as the up-and-down direction in Figure 1, etc. Furthermore, the positive direction in the X-axis direction is defined as the front, the positive direction in the Y-axis direction as the right side, and the positive direction in the Z-axis direction as the top. However, these directions are merely examples and are not intended to limit the direction in which the impact rotary tool 1 can be used. Also, the arrows indicating each direction in the drawings are for illustrative purposes only and do not represent actual objects.

[0021] (2.1) Configuration The impact rotary tool 1 of this embodiment is a portable electric tool. The impact rotary tool 1 is used, for example, to perform tasks such as tightening or loosening fastening members such as bolts or screws.

[0022] As described above, the impact rotary tool 1 of this embodiment comprises a motor 10, an output shaft 30, an impact mechanism 4, an inner cover 3, and a main body case 2.

[0023] (2.1.1) Main unit case The main case 2 houses the motor 10, output shaft 30, impact mechanism 4, and inner cover section 3. The main case 2 also houses the control circuit 5 and other components.

[0024] The main case 2 is composed of a right case 21, a left case 22, and a front case 23. When the right case 21, left case 22, and front case 23 are combined, the main case 2 has a storage section 2A, a grip section 2B, and a mounting section 2C.

[0025] The housing section 2A has a hollow cylindrical shape. The housing section 2A is divided by a partition wall 24 into a rear first housing chamber 2E and a front second housing chamber 2F. The first housing chamber 2E houses the motor 10, etc. The second housing chamber 2F houses the output shaft 30, the impact mechanism 4, and the middle cover section 3, etc. The partition wall 24 is provided with a recess 25 that forms a through hole for the rotation shaft 11 of the motor 10 when the right case 21 and the left case 22 are combined. The front case 23 is also provided with a round hole 26 for the tip of the output shaft 30 to pass through.

[0026] The grip portion 2B protrudes from the outer circumferential surface of the housing portion 2A in one direction along the radial direction of the housing portion 2A. This one direction is, for example, along the vertical direction (see Figure 3). The grip portion 2B is formed in a hollow cylindrical shape with the above-mentioned one direction as its longitudinal direction. The worker can grasp the grip portion 2B and perform tasks such as tightening screws. An operating portion 27 that receives input from the worker is provided on the grip portion 2B.

[0027] The internal space of the grip portion 2B is connected to the internal space of the housing portion 2A. The first end of the grip portion 2B in the longitudinal direction is connected to the housing portion 2A, and the second end of the grip portion 2B in the longitudinal direction is connected to the mounting portion 2C.

[0028] The battery pack BP1 is detachably attached to the mounting section 2C. Note that the battery pack BP1 is not shown in Figure 3, and is represented by a dashed line. The impact rotary tool 1 operates using the battery pack BP1 as its power source. That is, the battery pack BP1 is a power source that supplies the current to drive the motor 10. The battery pack BP1 is not a component of the impact rotary tool 1. However, the impact rotary tool 1 may include the battery pack BP1.

[0029] (2.1.2) Motor The motor 10 is housed in the housing section 2A (more specifically, the first housing chamber 2E) of the main case 2. The motor 10 is, for example, a brushless motor. The rotating shaft 11 of the motor 10 protrudes into the second housing chamber 2F through the recess 25. A pinion gear 12 is provided at the tip of the rotating shaft 11.

[0030] The torque and rotational speed of the motor 10 are controlled, for example, by a control circuit 5 (see Figure 3). The control circuit 5 is housed, for example, in the grip section 2B.

[0031] When an operator uses the impact rotary tool 1, the operator operates the control unit 27 located on the grip section 2B. For example, the control unit 27 is a so-called trigger switch, and the operator pulls the control unit 27 in. The control circuit 5 determines a target value for the rotational speed of the motor 10 according to the amount the control unit 27 is pulled in. The greater the amount the control unit 27 is pulled in, the higher the target value for the rotational speed of the motor 10 is set by the control circuit 5. The main body case 2 houses a drive circuit that drives the motor 10, and the drive circuit rotates the motor 10 at a rotational speed corresponding to the control signal input from the control circuit 5.

[0032] (2.1.3) Output shaft The output shaft 30 has a cylindrical shaft body 31 formed from, for example, a metal material with the front-to-back direction as the central axis. A rectangular prism-shaped connecting portion 34 is provided at the front end of the shaft body 31. The connecting portion 34 of the output shaft 30 is exposed to the outside through a round hole 26 in the front case 23. A tip tool T1 is attached to the connecting portion 34 of the output shaft 30. The tip tool T1 is, for example, a screwdriver bit or a socket bit. Screwdriver bits and socket bits are bits used to tighten or loosen fastening members such as bolts. A tip tool T1 suitable for the application is attached to the connecting portion 34 from among the various types of tip tools T1. A holder member for holding the tip tool T1 may be attached to the connecting portion 34, or the tip tool T1 may be attached via a holder member.

[0033] At the rear of the shaft 31, two impact-receiving portions 32 and 33 are provided side by side in the front-to-back direction, projecting radially in opposite directions. The impact-receiving portion 32 is located behind the impact-receiving portion 33. The two impact-receiving portions 32 and 33 are shaped like a fan when viewed from the front.

[0034] (2.1.4) Impact Mechanism The impact mechanism 4 is housed in the housing section 2A (more specifically, the second housing chamber 2F) of the main case 2. The impact mechanism 4 receives the rotational force of the motor 10 and rotates the output shaft 30 by striking the impact targets 32 and 33 of the output shaft 30.

[0035] The impact mechanism 4 comprises two hammer members 40A and 40B, two cam pins 80 and 81, and an inner cover portion 3 that houses the hammer members 40A and 40B. The impact mechanism 4 also further comprises striking portions 32 and 33 provided on the output shaft 30. The inner cover portion 3 is constructed by combining multiple members. The inner cover portion 3 is formed in a cylindrical shape as a whole. In this embodiment, the inner cover portion 3 is constructed by combining multiple members, namely a first cylindrical body 60 and a second cylindrical body 70. Since the inner cover portion 3 is constructed by combining multiple members, the work of housing the impact mechanism 4 inside the inner cover portion 3 can be easily performed. The first cylindrical body 60 is fastened and fixed to the second cylindrical body 70 using, for example, a fastening member such as a screw.

[0036] Furthermore, the interior of the middle cover portion 3 is filled with a lubricant (not shown). That is, the impact rotary tool 1 further includes a lubricant filled inside the middle cover portion 3. The lubricant is, for example, lubricating grease used for lubricating machinery, and is filled at the contact points between the impacted portions 32, 33 of the output shaft 30 and the hammer members 40A, 40B. By filling the contact points between the impacted portions 32, 33 of the output shaft 30 and the hammer members 40A, 40B with lubricant, the occurrence of wear due to impact can be reduced. Note that in the impact rotary tool 1 of this embodiment, it is not essential that the interior of the middle cover portion 3 is filled with lubricant, and the lubricant can be omitted as appropriate.

[0037] The first cylindrical body 60 is formed as a bottomed cylinder with a closed rear end, consisting of a hollow cylindrical portion 61 and a disc-shaped rear wall 62 that closes the rear end of the cylindrical portion 61. A circular recess 65 is provided at the center of the front surface of the rear wall 62, into which the disc portion 35 at the rear end of the output shaft 30 is inserted. The rear wall 62 also has a hole at the bottom of the recess 65 into which a pinion gear 12, which is integrally attached to the rotating shaft 11 of the motor 10, is inserted, and an internal gear 63 that meshes with the pinion gear 12 is provided on the inner circumferential surface of the hole. As a result, when the rotating shaft 11 of the motor 10 rotates, the first cylindrical body 60 rotates. In other words, the middle cover portion 3 rotates in conjunction with the rotation of the rotating shaft 11 of the motor 10. By rotating the middle cover portion 3, the energy from the impact can be converted into inertial energy, thereby increasing the output torque. Furthermore, the rear wall 62 is provided with two retaining holes 64, each into which the rear ends of two cam pins 80 and 81 are inserted, at positions symmetrical to each other with respect to the center of the cylindrical portion 61.

[0038] The second cylindrical body 70 is formed in a closed-bottom cylindrical shape with a hollow cylindrical portion 71 and a disc-shaped front wall 72 that closes the front end of the cylindrical portion 71. A round hole 73 for passing the output shaft 30 is provided in the center of the front wall 72. On the rear surface of the front wall 72, two retaining holes 74 are provided, opposite to the two retaining holes 64 provided in the rear wall 62 of the first cylindrical body 60, into which the front ends of two cam pins 80 and 81 are inserted. The two retaining holes 74 are provided in positions symmetrical to each other with respect to the center position of the cylindrical portion 71.

[0039] Since the two hammer members 40A and 40B have the same shape, we will explain the shape using hammer member 40A as an example, and the explanation for hammer member 40B will be omitted as appropriate. Hammer members 40A and 40B are arranged side by side in the front-to-back direction, with hammer member 40A positioned behind hammer member 40B.

[0040] The hammer member 40A has an oval shape when viewed from the front, and is provided with an insertion hole 41 in the center into which the striking portion 32 of the output shaft 30 is inserted. The hammer member 40A is cylindrical with an insertion hole 41 into which the output shaft 30 is inserted. The striking portion 33 of the output shaft 30 is inserted into the insertion hole 41 of the hammer member 40B.

[0041] On the outer circumferential surface of the hammer member 40A, a first groove 43 into which the cam pin 80 is inserted and a second groove 44 into which the cam pin 81 is inserted are provided, positioned opposite each other with the insertion hole 41 in between. In other words, the hammer member 40A is provided with a first groove 43 and a second groove 44 into which the two cam pins 80 and 81 fixed to the middle cover portion 3 are respectively inserted. The width of the first groove 43 is formed to be wider than the diameter of the cam pin 81. The width of the second groove 44 is formed to be approximately the same as the diameter of the cam pin 81. In addition, on the inner surface of the insertion hole 41, two striking portions 42 are provided on either side of the second groove 44, on the side closer to the second groove 44. The two striking portions 42 are provided so as to protrude inward from the inner surface of the insertion hole 41.

[0042] As shown in Figure 4, the hammer member 40A is housed inside the middle cover 3 with the cam pin 80 inserted into the first groove 43 and the cam pin 81 inserted into the second groove 44. On the other hand, as shown in Figure 5, the hammer member 40B is housed inside the middle cover 3 with the cam pin 81 inserted into the first groove 43 and the cam pin 80 inserted into the second groove 44. In other words, the hammer members 40A and 40B are housed inside the middle cover 3 such that they face opposite directions from each other in the direction in which the two cam pins 80 and 81 are aligned.

[0043] (2.2) Assembly Instructions As described above, the main body case 2 of the impact rotary tool 1 houses the motor 10, output shaft 30, impact mechanism 4, inner cover 3, control circuit 5, and the like.

[0044] The impact mechanism 4 and the inner cover section 3 are assembled as follows. Note that the assembly method described below is just one example, and the order of assembly can be changed as appropriate.

[0045] For example, the assembler inserts the rear ends of two cam pins 80 and 81 into two retaining holes 64 provided in the rear wall 62 of the first cylindrical body 60 which constitutes the middle cover part 3. Next, the assembler inserts the hammer member 40A into the first cylindrical body 60 such that the cam pin 80 is inserted into the first groove 43 and the cam pin 81 is inserted into the second groove 44 (see Figure 4). The assembler also inserts the hammer member 40B into the first cylindrical body 60 such that the cam pin 80 is inserted into the second groove 44 and the cam pin 81 is inserted into the first groove 43. The assembler then inserts the output shaft 30 into the first cylindrical body 60 such that the rear striking part 32 of the output shaft 30 is inserted into the insertion hole 41 of the rear hammer member 40A and the front striking part 33 of the output shaft 30 is inserted into the insertion hole 41 of the front hammer member 40B. At this time, the disc portion 35 at the rear end of the output shaft 30 is inserted into the recess 65 in the rear wall 62 of the first cylinder 60. Then, the assembler fills the inside of the first cylinder 60 with lubricant, places the second cylinder 70 over the front of the first cylinder 60, inserts the front ends of the cam pins 80 and 81 into the two retaining holes 74 of the second cylinder 70, and fastens and secures the first cylinder 60 and the second cylinder 70 with fastening members such as screws or bolts. With the first cylinder 60 and the second cylinder 70 combined to form the middle cover portion 3, the front end portion of the output shaft 30 protrudes forward from the round hole 73 of the second cylinder 70.

[0046] Next, with the pinion gear 12 of the motor 10's rotating shaft 11 inserted into the internal gear 63 of the first cylindrical body 60, the assembler inserts the motor 10 into the first housing chamber 2E of the right case 21, and inserts the middle cover section 3, which houses the output shaft 30 and the impact mechanism 4, into the second housing chamber 2F of the right case 21. The assembler then places the control circuit 5 and the operating section 27, etc., into the grip section 2B of the right case 21, and then places the left case 22 on top of the right case 21, fastening the right case 21 and the left case 22 together with fastening members such as screws or bolts. Then, with the right case 21 and the left case 22 joined, the assembler places the front case 23 on top so as to close the openings that are created at the front ends of the right case 21 and the left case 22, and fastens the right case 21 and the left case 22 together with the front case 23 using fastening members such as screws or bolts. At this time, the tip of the output shaft 30 protrudes forward from the round hole 26 of the front case 23. A bearing 82 (see Figure 2) is attached to the rotating shaft 11 of the motor 10, and the rotating shaft 11 of the motor 10 is rotatably supported by the right case 21 and the left case 22 via the bearing 82. In addition, a bearing 83 (see Figure 2) is attached to the output shaft 30, and the output shaft 30 is rotatably supported by the front case 23 via the bearing 83.

[0047] After the impact rotary tool 1 is assembled as described above, when the battery pack BP1 is attached to the mounting section 2C, the battery pack BP1 becomes capable of supplying power to the control circuit 5 and other components, allowing the operator to perform work using the impact rotary tool 1.

[0048] (2.3) Operation Description When an operator performing a tightening operation using the impact rotary tool 1 pulls in the operating section 27 of the impact rotary tool 1, the control circuit 5 determines a target value for the rotational speed of the motor 10 according to the amount the operating section 27 is pulled in, and outputs a control signal to the drive circuit. The drive circuit rotates the motor 10 by controlling the power supplied to the motor 10 according to the control signal from the control circuit 5. When the rotation shaft 11 of the motor 10 rotates in a counterclockwise direction when viewed from the front, the pinion gear 12 at the tip of the rotation shaft 11 meshes with the internal gear 63 of the middle cover section 3, so the middle cover section 3 rotates in a counterclockwise direction when viewed from the front. Since the cam pins 80 and 81 attached to the middle cover section 3 are inserted into the first groove 43 and second groove 44 of the hammer members 40A and 40B, when the middle cover section 3 rotates, the hammer members 40A and 40B rotate together with the middle cover section 3.

[0049] Here, as the central cover portion 3 rotates, the hammer member 40A rotates counterclockwise from the position shown in Figure 4 (in the direction indicated by arrow D1 in Figure 4), causing the striking portion 42 on the right side of the hammer member 40A to collide with the striking portion 32 of the output shaft 30. The hammer member 40A is pivotable around the cam pin 81 inserted in the second groove 44, within the range in which the cam pin 80 can move within the first groove 43. Therefore, the hammer member 40A pivots around the cam pin 81 inserted in the second groove 44 until the cam pin 80 moves to the end of the first groove 43. Subsequently, as the hammer member 40A rotates further counterclockwise in response to the rotation of the central cover 3, the striking part 42 moves over the struck part 32, and the inner circumferential surface of the insertion hole 41 is pressed against the struck part 32, causing the hammer member 40A to swing in the opposite direction to the above-mentioned direction, with the cam pin 81 inserted in the second groove 44 as the pivot point.

[0050] Incidentally, the impacted portion 33 of the output shaft 30 protrudes in the opposite direction to the impacted portion 32, and the hammer member 40B is positioned in the opposite direction to the hammer member 40A. Therefore, as the middle cover portion 3 rotates, when the hammer member 40B rotates counterclockwise from the position shown in Figure 5 (in the direction indicated by arrow D2 in Figure 5), the left impact portion 42 of the hammer member 40B collides with the impacted portion 33 at the same time that the right impact portion 42 of the hammer member 40A collides with the impacted portion 32. At this time, the hammer member 40B can swing with the cam pin 81 inserted in the second groove 44 as a pivot point, within the range in which the cam pin 81 can move within the first groove 43. Therefore, the hammer member 40B swings in one direction with the cam pin 81 inserted in the second groove 44 as a pivot point until the cam pin 81 moves to the end of the first groove 43. Subsequently, as the hammer member 40B rotates further counterclockwise in response to the rotation of the central cover 3, the striking part 42 moves over the struck part 33, and the inner circumferential surface of the insertion hole 41 is pressed against the struck part 33. As a result, the hammer member 40B swings in the opposite direction to the one described above, with the cam pin 80 inserted in the second groove 44 as the pivot point.

[0051] In this way, as the central cover 3 rotates in accordance with the rotation of the motor 10's rotating shaft 11, the respective striking parts 42 of the hammer members 40A and 40B strike the striking parts 32 and 33 of the output shaft 30 in accordance with the rotation of the central cover 3, causing the output shaft 30 to rotate. As a result, the output shaft 30 rotates due to the impact force applied from the impact mechanism 4, enabling the realization of a high-torque impact rotary tool 1, and the tip tool T1 held on the output shaft 30 is used to tighten or loosen fastening members.

[0052] Furthermore, if the motor 10's rotating shaft 11 rotates clockwise when viewed from the front, a different striking part 42 of the hammer members 40A and 40B, which would strike the parts to be struck 32, 32 if the rotating shaft 11 rotated counterclockwise when viewed from the front, will strike the parts to be struck 32, 32, thus allowing the output shaft 30 to be rotated by the impact.

[0053] In this embodiment, the output shaft 30 of the impact rotary tool 1 is provided with two impact targets 32 and 33 at positions symmetrical to each other with respect to the rotation center of the output shaft 30. The impact mechanism 4 has two hammer members 40A and 40B, each corresponding to the two impact targets 32 and 33. In accordance with the rotation of the motor 10, each of the two hammer members 40A and 40B strikes the corresponding impact target 32 ​​and 33 of the two impact targets 32 and 33. By striking the two impact targets 32 and 33 of the output shaft 30 with the two hammer members 40A and 40B, the impact force can be evenly distributed to the two impact targets 32 and 33 that are positioned symmetrically to each other with respect to the rotation center of the output shaft 30. Therefore, by striking the two impact targets 32 and 33 of the output shaft 30 with the two hammer members 40A and 40B, the output shaft 30 can be rotated smoothly.

[0054] Furthermore, since the striking portions 42 of the two hammer members 40A and 40B strike the target portions 32 and 33, which protrude in opposite directions from the center of the output shaft 30, at the same time, the striking force is transmitted to the output shaft 30 in a balanced manner, allowing the output shaft 30 to rotate smoothly. Note that the timing at which the striking portion 42 of hammer member 40A strikes the target portion 32 and the timing at which the striking portion 42 of hammer member 40B strikes the target portion 33 are not limited to being exactly the same timing. It is sufficient if the time difference between the timing at which the striking portion 42 of hammer member 40A strikes the target portion 32 and the timing at which the striking portion 42 of hammer member 40B strikes the target portion 33 is 10% or less of the rotation period of the middle cover portion 3.

[0055] (3) Variant The above embodiments are merely one of many embodiments of this disclosure. The above embodiments can be modified in various ways depending on the design, etc., as long as they achieve the objectives of this disclosure.

[0056] The following lists modifications of the above embodiment. The modifications described below can be combined and applied as appropriate. In the following description, the above embodiment may also be referred to as the basic configuration.

[0057] (3.1) Variation 1 The impact rotary tool 1 according to Modification 1 of this embodiment will be described with reference to Figures 6 and 7. The impact rotary tool 1 according to Modification 1 differs from the basic configuration in that the middle cover portion 3A is fixed to the main body case 2. In the impact rotary tool 1 according to Modification 1, components common to the basic configuration are given the same reference numerals, and their descriptions are omitted.

[0058] In the basic configuration, the central cover section 3 also serves as the cam case for holding the hammer members 40A and 40B. However, in the modified example 1, the impact rotary tool 1 has a separate cam case 50 for holding the hammer members 40A and 40B, distinct from the central cover section 3A. In the modified example 1, the hammer members 40A and 40B, the cam case 50, and the impacted parts 32 and 33 of the output shaft 30 are covered by the central cover section 3A, and the central cover section 3A and the cam case 50 are separate components.

[0059] The cam case 50 is formed in a frame shape by a pair of first plate pieces 51, 52 that face each other in the axial direction of the output shaft 30, and a pair of second plate pieces 53, 53 that connect the ends of the pair of first plate pieces 51, 52.

[0060] The pair of first plate pieces 51 and 52 are formed in a rectangular plate shape.

[0061] The first plate piece 51 has a through hole 56 in the center of its longitudinal direction into which the output shaft 30 is inserted, and two through holes 54 are provided at positions symmetrical to the center of the through hole 56. The first ends (front ends) of two cam pins 80 and 81 in the longitudinal direction are inserted into the two through holes 54 of the first plate piece 51, respectively.

[0062] The first plate piece 52 has a through hole 57 in the center of its longitudinal direction into which the output shaft 30 is inserted, and two through holes 55 are provided at positions symmetrical to the center of the through hole 57. The second ends (rear ends) of two cam pins 80 and 81 in the longitudinal direction are inserted into the two through holes 55 of the first plate piece 52, respectively.

[0063] In the cam case 50, with two hammer members 40A and 40B inserted into the space between a pair of first plate pieces 51 and 52, cam pins 80 and 81 are inserted into the through holes 54 and 55 of the first plate pieces 51 and 52. At this time, cam pin 80 is inserted into the first groove 43 of hammer member 40A and the second groove 44 of hammer member 40B, and cam pin 81 is inserted into the second groove 44 of hammer member 40A and the first groove 43 of hammer member 40B. As a result, hammer member 40A is held in the cam case 50 in a state where it can pivot around cam pin 81 inserted in the second groove 44. Similarly, hammer member 40B is held in the cam case 50 in a state where it can pivot around cam pin 80 inserted in the second groove 44.

[0064] Furthermore, an internal gear is provided at the rear of the through hole 57 in the first plate piece 52, which meshes with a pinion gear 12 provided on the rotating shaft 11 of the motor 10. When the rotating shaft 11 of the motor 10 rotates, the cam case 50 rotates together with the rotating shaft 11. When the cam case 50 rotates, the striking part 42 of the hammer member 40A strikes the struck part 32 of the output shaft 30, and the striking part 42 of the hammer member 40B strikes the struck part 33 of the output shaft 30, thereby applying a striking force to the output shaft 30 and causing the output shaft 30 to rotate. Note that the operation of the hammer members 40A and 40B striking the output shaft 30 is the same as in the basic configuration, so a detailed explanation is omitted.

[0065] In the modified example 1, the impact rotary tool 1 is equipped with a cam case 50 that holds the hammer members 40A and 40B, so the impact mechanism 4 includes the hammer members 40A and 40B, the cam case 50, the cam pins 80 and 81, and the impacted parts 32 and 33 of the output shaft 30.

[0066] The middle cover section 3A is composed of a rear first cylindrical body 90 and a front second cylindrical body 95. The first cylindrical body 90 is fastened and fixed to the second cylindrical body 95 using fastening members such as screws. The inside of the middle cover section 3A is filled with a lubricant (not shown). The lubricant is, for example, lubricating grease used for lubricating machinery, and is filled into the contact area between the impacted parts 32, 33 of the output shaft 30 and the hammer members 40A, 40B. By filling the contact area between the impacted parts 32, 33 of the output shaft 30 and the hammer members 40A, 40B with lubricant, the occurrence of wear due to impact can be reduced.

[0067] The first cylindrical body 90 is formed in a closed-bottom cylindrical shape with a hollow cylindrical portion 91 and a disc-shaped rear wall 92 that closes the rear end of the cylindrical portion 91. A through hole 93 into which the rotating shaft 11 of the motor 10 is inserted is provided at the center of the rear wall 92.

[0068] The second cylindrical body 95 is formed as a bottomed cylindrical shape with a closed front end, consisting of a hollow cylindrical portion 96 and a disc-shaped front wall 97 that closes the front end of the cylindrical portion 96. A round hole 98 for passing the output shaft 30 is provided in the center of the front wall 97.

[0069] The middle cover section 3A is fixed to the main body case 2 in an appropriate manner, while housing the hammer members 40A and 40B, the cam case 50, the cam pins 80 and 81, and the striking parts 32 and 33 of the output shaft 30. In other words, the middle cover section 3A is fixed to the main body case 2 and does not rotate in conjunction with the rotation shaft 11 of the motor 10. Therefore, the load on the motor 10 can be reduced compared to when the middle cover section 3 rotates in conjunction with the rotation shaft 11 of the motor 10. The cam case 50 is housed inside the middle cover section 3A in a rotatable state and rotates in accordance with the rotation of the rotation shaft 11 of the motor 10.

[0070] In the impact rotary tool 1 of the modified example 1, the impact mechanism 4 is covered by the inner cover portion 3A, so when the hammer members 40A and 40B strike the parts to be struck 32 and 33, impact noise is generated and the impact noise transmitted to the outside of the main body case 2 can be reduced. In addition, although the inner cover portion 3A is filled with lubricant for lubricating the impact mechanism 4, the inner cover portion 3A can suppress the scattering of lubricant, so the lubricating effect of the lubricant is less likely to decrease and wear of the parts constituting the impact mechanism 4 can be suppressed.

[0071] In addition, in the impact rotary tool 1 of the modified example 1, the middle cover portion 3A is fixed to the main body case 2, so the output torque of the motor 10 can be reduced compared to the case where the middle cover portion 3A rotates in conjunction with the rotation of the motor shaft 11 of the motor 10.

[0072] (3.2) Variation 2 The impact rotary tool 1 according to Modification 2 will be described with reference to Figures 8 and 9. The impact rotary tool 1 according to Modification 2 differs from the basic configuration in that it further includes a sealing part 100 that seals the middle cover part 3B. Note that the impact rotary tool 1 according to Modification 2 has the same configuration as the basic configuration except that the middle cover part 3B includes the sealing part 100, so the same reference numerals are used for components common to the basic configuration, and their explanations are omitted.

[0073] In this disclosure, "sealing" the inner cover portion 3B is not limited to airtight sealing of the inner cover portion 3B, but may also include closing the gaps in the inner cover portion 3B so that the gaps in the inner cover portion 3B become smaller.

[0074] The middle cover portion 3B of the impact rotary tool 1 according to the modified example 2 is composed of a cylindrical body 110 and a lid member 120. The cylindrical body 110 and the lid member 120 are made of, for example, a metal material.

[0075] The cylindrical body 110 is formed in a closed-bottom cylindrical shape with a hollow cylindrical portion 111 and a rear wall 112 that closes the rear end of the cylindrical portion 111. A circular recess 113 is provided at the center of the front surface of the rear wall 112, into which the disc portion 35 at the rear end of the output shaft 30 is inserted. Similar to the first cylindrical body 60 of the basic configuration, the front surface of the rear wall 112 is provided with two retaining holes (not shown) into which the rear ends of cam pins 80 and 81 (not shown) are inserted, respectively.

[0076] An internal gear 114 is provided at the center of the rear surface of the rear wall 112, which meshes with a pinion gear 12 integrally mounted on the rotating shaft 11 of the motor 10. As a result, when the rotating shaft 11 of the motor 10 rotates, the cylindrical body 110 rotates. In other words, the inner cover portion 3B rotates in conjunction with the rotation of the rotating shaft 11 of the motor 10.

[0077] The front end of the cylindrical portion 111 is provided with a ring-shaped flange portion 115 that protrudes radially outward. The front surface of the flange portion 115 is provided with a groove 116 into which an O-ring 101, which is a sealing portion 100, is inserted.

[0078] The cover member 120 is formed in a disc shape. A round hole 121 is provided at the center of the cover member 120 for passing the shaft 31 of the output shaft 30 through. On the front surface of the cover member 120, a cylindrical rib 122 is provided around the round hole 121. Inside the rib 122, an oil seal 102 is arranged as a sealing part 100 to close the gap between the rotating output shaft 30 and the cover member 120. On the rear surface of the cover member 120, a large-diameter hole 123 is provided, which has a larger diameter than the round hole 121, and the shaft 31 of the output shaft 30 is inserted inside the large-diameter hole 123.

[0079] The cylindrical body 110 and the lid member 120 are fastened together, for example, by two screws 130. When assembling the inner cover 3B, the assembler first places the cam pins 80, 81, the hammer members 40A, 40B, and the output shaft 30 inside the cylindrical body 110, fills it with lubricant, and inserts the O-ring 101 into the groove 116 of the cylindrical body 110. Then, the assembler inserts the shaft 31 of the output shaft 30 into the large-diameter hole 123 of the lid member 120, and places the rear surface of the lid member 120 over the flange 115 of the cylindrical body 110, and fastens the cylindrical body 110 and the lid member 120 together with two screws 130. At this time, the tip of the output shaft 30 protrudes forward from the round hole 121 of the lid member 120, and the oil seal 102 installed inside the rib 122 of the lid member 120 contacts the circumferential surface of the shaft body 31 of the output shaft 30. In this way, the assembly of the middle cover 3B is completed, and the assembly worker inserts the assembled middle cover 3B into the second storage chamber 2F of the right case 21 or the left case 22.

[0080] When the inner cover portion 3B is assembled, the gap between the flange portion 115 of the cylindrical body 110 and the lid member 120 is closed by the O-ring 101. Furthermore, in the portion where the shaft 31 is inserted into the large-diameter hole 123 of the lid member 120, the gap between the lid member 120 and the shaft 31 is bent in a crank shape when viewed from a direction perpendicular to the radius of the shaft 31. Therefore, compared to the case where the gap between the lid member 120 and the shaft 31 is straight, the amount of lubricant leaking from the gap between the lid member 120 and the shaft 31 can be reduced. In addition, the oil seal 102 installed inside the rib 122 contacts the surface of the shaft 31 of the output shaft 30, further reducing the amount of lubricant leaking from the gap between the lid member 120 and the shaft 31. As a result, in the impact rotary tool 1 of the modified example 2, the lubricant filled in the inner cover portion 3B is less likely to leak out of the inner cover portion 3B, and the decrease in the lubricating effect due to the lubricant can be further suppressed. In this case, the sealing portion 100 is formed by the O-ring 101 and the oil seal 102 in the middle cover portion 3B shown in Figures 8 and 9.

[0081] In the middle cover section 3B shown in Figures 8 and 9, the cylindrical body 110 and the lid member 120 are joined by screw fastening with screws 130, but the method of joining the cylindrical body 110 and the lid member 120 is not limited to the above method.

[0082] For example, as shown in Figures 10 and 11, the cylindrical body 110 and the lid member 120 may be fixed using a retaining ring 131. The inner cover portion 3B shown in Figures 10 and 11 has the same configuration as the inner cover portion 3B shown in Figures 8 and 9, except that the cylindrical body 110 and the lid member 120 are connected by a retaining ring 131, and the same reference numerals are used for common components, and their explanation is omitted.

[0083] In the inner cover portion 3B shown in Figures 10 and 11, a stepped portion 117 is provided on the inner surface of the cylindrical portion 111 of the cylindrical body 110, which contacts a part of the rear surface of the lid member 120. In addition, a groove 118 into which the retaining ring 131 fits is provided along the circumferential direction on the inner surface of the cylindrical portion 111 of the cylindrical body 110, in front of the stepped portion 117.

[0084] The lid member 120 has a disc shape, and its external dimensions are set to be slightly smaller than the internal diameter of the opening of the cylindrical body 110. The lid member 120 is inserted into the cylindrical body 110, and a portion of its rear surface contacts the stepped portion 117, positioning it so that it cannot move further backward. Furthermore, when a portion of the rear surface of the lid member 120 inserted into the cylindrical body 110 is in contact with the stepped portion 117, the front surface of the lid member 120 is positioned slightly behind the groove 118 of the cylindrical body 110.

[0085] The lid member 120 is formed in a disc shape. A circular hole 121 is provided at the center of the lid member 120 for passing the shaft 31 of the output shaft 30 through. On the front surface of the lid member 120, a cylindrical rib 122 is provided around the circular hole 121. Inside the rib 122, an oil seal 102 is positioned as a sealing portion 100 to close the gap between the rotating output shaft 30 and the lid member 120. On the rear surface of the lid member 120, a large-diameter hole 123 is provided, which has a larger diameter than the circular hole 121, and the shaft 31 of the output shaft 30 is inserted inside the large-diameter hole 123. In addition, a groove 125 into which the O-ring 101, which is the sealing portion 100, is inserted is provided around the entire circumference of the side surface of the lid member 120 (the surface facing the inner surface of the cylindrical portion 111).

[0086] When assembling the inner cover section 3B, the assembler first places the cam pins 80, 81, hammer members 40A, 40B, and output shaft 30 inside the cylindrical body 110 and fills it with lubricant. Then, when the assembler inserts the lid member 120, which has an O-ring 101 fitted into the groove 125, into the cylindrical body 110, the shaft 31 of the output shaft 30 is inserted into the large-diameter hole 123 of the lid member 120, and the tip of the shaft 31 protrudes forward from the round hole 121. At this time, a part of the rear surface of the lid member 120 comes into contact with the stepped portion 117, which restricts the rearward movement of the lid member 120. Subsequently, when the assembly worker inserts the retaining ring 131 into the groove 118 of the cylindrical body 110, the lid member 120 is held between the retaining ring 131 and the stepped portion 117, the cylindrical body 110 and the lid member 120 are joined together, and the opening of the cylindrical body 110 is closed by the lid member 120. The assembly worker then attaches the oil seal 102 to the inside of the rib 122 of the lid member 120 to complete the assembly of the middle cover 3B, and inserts the completed middle cover 3B into the second storage chamber 2F of the right case 21 or the left case 22.

[0087] When the inner cover section 3B is assembled, the gap between the inner surface of the cylindrical body 110 and the lid member 120 is sealed by the O-ring 101. Furthermore, in the portion where the shaft 31 is inserted into the large-diameter hole 123 of the lid member 120, the gap between the lid member 120 and the shaft 31 is bent in a crank shape when viewed from a direction perpendicular to the radius of the shaft 31. Therefore, compared to the case where the gap between the lid member 120 and the shaft 31 is straight, the amount of lubricant leaking from the gap between the lid member 120 and the shaft 31 can be reduced. In addition, the oil seal 102 installed inside the rib 122 contacts the surface of the shaft 31 of the output shaft 30, further reducing the amount of lubricant leaking from the gap between the lid member 120 and the shaft 31. As a result, even in the retaining ring-fixed inner cover section 3B shown in Figures 10 and 11, the lubricant filled in the inner cover section 3B is less likely to leak out of the inner cover section 3B, further suppressing the decrease in the lubricating effect of the lubricant. In the middle cover portion 3B shown in Figures 10 and 11, the sealing portion 100 is formed by the O-ring 101 and the oil seal 102.

[0088] Furthermore, the method of connecting the cylindrical body 110 and the lid member 140 may be a case screw fixing method as shown in Figures 12 to 14. The case screw fixing method is a method of connecting the cylindrical body 110 and the lid member 140 by screwing a male threaded portion provided on one of the cylindrical body 110 and the lid member 140 into a female threaded portion provided on the other of the cylindrical body 110 and the lid member 140. Note that the inner cover portion 3B shown in Figures 12 to 14 has the same configuration as the inner cover portion 3B shown in Figures 8 and 9, except for the fact that the cylindrical body 110 and the lid member 140 are connected by case screw fixing, so the same reference numerals are used for common components and their explanation is omitted.

[0089] The cylindrical body 110 is provided with a male threaded portion 149 on the front side of the outer circumferential surface of the cylindrical portion 111. Furthermore, the outer circumferential surface of the cylindrical portion 111 is provided with a projection 119 that extends radially outward from a point behind the male threaded portion 149. The projection 119 extends in a band shape along the circumferential direction of the cylindrical portion 111.

[0090] The cylindrical body 110 houses two cam pins 80 and 81, two hammer members 40A and 40B, and an output shaft 30. The cylindrical body 110 also houses a support plate 150 that supports the front ends of the two cam pins 80 and 81. The support plate 150 is provided with a through hole 151 into which the shaft 31 of the output shaft 30 is inserted, and two through holes 152 into which the front ends of the two cam pins 80 and 81 are inserted, respectively.

[0091] The lid member 140 is formed in a closed-end cylindrical shape with a closed front end, consisting of a cylindrical portion 142 into which the cylindrical portion 111 of the cylindrical body 110 is inserted, and a front wall portion 141 that closes the front end of the cylindrical portion 142.

[0092] The inner surface of the cylindrical portion 142 is provided with a female threaded portion 144 that engages with the male threaded portion 149 of the cylindrical body 110. In addition, a projection 145 that protrudes forward is provided in the center of the front wall portion 141. A round hole 147 into which the output shaft 30 is inserted is provided in the center of the front surface of the projection 145. An oil seal 102 is positioned in the recess 146 on the inside of the projection 145 as a sealing portion 100, which closes the gap between the rotational output shaft 30 and the lid member 140.

[0093] When assembling the inner cover section 3B, the assembler first places the cam pins 80, 81, hammer members 40A, 40B, and output shaft 30 inside the cylindrical body 110, fills it with lubricant, and then places the support plate 150 inside. At this time, the output shaft 30 is inserted into the through hole 151 of the support plate 150, and the front ends of the two cam pins 80, 81 are inserted into the two through holes 152 of the support plate 150. Next, the assembler places the O-ring 101 in front of the projection 119 on the outer surface of the cylindrical body 110, and places the oil seal 102 in the recess 146 of the lid member 140, and then inserts the cylindrical body 110 into the cylindrical portion 142 of the lid member 140 from the rear, and inserts the front end of the output shaft 30 housed in the cylindrical body 110 into the round hole 147 of the lid member 140. The assembly worker then rotates the lid member 140 relative to the cylindrical body 110 and screws the male threaded portion 149 of the cylindrical body 110 into the female threaded portion 144 of the lid member 140, thereby joining the cylindrical body 110 and the lid member 140. The assembly worker then inserts the assembled middle cover 3B into the second storage chamber 2F of the right case 21 or the left case 22.

[0094] When the inner cover portion 3B is assembled, the male thread portion 149 of the cylindrical body 110 and the female thread portion 144 of the lid member 140 engage, thereby closing the gap between the inner circumferential surface of the cylindrical portion 142 of the lid member 140 and the outer circumferential surface of the cylindrical body 110. Furthermore, since an O-ring 101 is placed between the inner circumferential surface of the cylindrical portion 142 of the lid member 140 and the outer circumferential surface of the cylindrical body 110, the gap between the inner circumferential surface of the cylindrical portion 142 of the lid member 140 and the outer circumferential surface of the cylindrical body 110 is further closed by the O-ring 101. In addition, the oil seal 102 installed in the recess 146 of the lid member 140 contacts the surface of the shaft 31 of the output shaft 30, thereby reducing the amount of lubricant leaking out from the gap between the lid member 140 and the shaft 31. As a result, even in the case screw-fixed inner cover portion 3B shown in Figures 12 to 14, the lubricant filled in the inner cover portion 3B is less likely to leak out to the outside of the inner cover portion 3B, further suppressing the decrease in the lubricating effect of the lubricant. In the inner cover portion 3B shown in Figures 12 to 14, the sealing portion 100 is formed by the O-ring 101 and the oil seal 102.

[0095] Furthermore, the configuration of Modified Example 2 may be applied to the impact rotary tool 1 of Modified Example 1, and by sealing the middle cover portion 3A with the sealing portion 100, the possibility of the lubricant filled in the middle cover portion 3A leaking out can be reduced.

[0096] (3.3) Modification example 3 The hammer members 40A and 40B of the impact rotary tool 1 according to Modification 3 will be described with reference to Figure 15. The impact rotary tool 1 according to Modification 3 differs from the basic configuration in that the hammer members 40A and 40B are provided with a connecting portion that connects the inner surface 411 and the outer surface 412 of the cylindrical body (hammer members 40A and 40B). Here, the inner surface 411 of the hammer members 40A and 40B is the wall surface of the insertion hole 41 provided in the hammer members 40A and 40B, and the outer surface 412 of the hammer members 40A and 40B is the side surface of the cylindrically formed hammer members 40A and 40B. Note that the impact rotary tool 1 according to Modification 3 has the same configuration as the basic configuration except for the fact that the hammer members 40A and 40B are provided with a connecting portion, so the same reference numerals are used for components common to the basic configuration and their explanations are omitted.

[0097] In the basic configuration of the impact rotary tool 1, as explained in "(2.3) Operation Description," when the middle cover 3 rotates in accordance with the rotation of the motor 10's rotating shaft 11, the striking parts 42 of the hammer members 40A and 40B housed in the middle cover 3 strike the impacted parts 32 and 33 of the output shaft 30, respectively. For example, when the striking part 42 of the hammer member 40A strikes the impacted part 32 of the output shaft 30, the hammer member 40A swings around the cam pin 81, causing the striking part 42 to move over the impacted part 32. However, if the middle cover 3 is filled with lubricant, depending on the viscosity or consistency of the lubricant, the lubricant present between the inner surface of the middle cover 3 and the hammer member 40A may create resistance when the hammer member 40A attempts to swing around the cam pin 81, potentially hindering the swing of the hammer member 40A. If the swinging of the hammer member 40A around the cam pin 81 is inhibited, the striking portion 42 of the hammer member 40A may not be able to overcome the struck portion 32, potentially causing the impact mechanism 4, including the hammer member 40A, to lock up.

[0098] Therefore, the hammer member 40A of the impact rotary tool 1 of the modified example 3 is provided with a communication portion connecting the inner surface 411 and the outer surface 412 of the hammer member 40A in a direction intersecting the axial direction of the output shaft 30, and a lubricant is movable through this communication portion. Here, the communication portion provided on the hammer member 40A may be a groove 45 provided on the surface of the hammer member 40A, or a through hole 46 that penetrates the hammer member 40A.

[0099] For example, the hammer member 40A shown in Figure 15 is cylindrical with an oval shape when viewed along the axial direction of the output shaft 30, and two recessed grooves 45 and through holes 46 are provided as connecting parts at two points that intersect with the direction connecting the first groove 43 and the second groove 44.

[0100] The two grooves 45 extend along both sides of the hammer member 40A in the axial direction of the output shaft 30, in a direction intersecting the axial direction of the output shaft 30 and intersecting the direction connecting the first groove 43 and the second groove 44. The two grooves 45 are provided from the inner surface 411 to the outer surface 412 of the cylindrical hammer member 40A.

[0101] Furthermore, the through-hole 46 is provided so as to penetrate the hammer member 40A in a direction intersecting the axial direction of the output shaft 30 and the direction connecting the first groove 43 and the second groove 44. One end of the through-hole 46 opens to the inner surface 411, and the other end of the through-hole 46 opens to the outer surface 412.

[0102] In the impact rotary tool 1 of the modified example 3, when the striking portion 42 of the hammer member 40A strikes the struck portion 32 of the output shaft 30 in accordance with the rotation of the middle cover portion 3, the hammer member 40A swings around the cam pin 81, allowing the lubricant present between the inner surface of the middle cover portion 3 and the hammer member 40A to flow (pass through) through the two grooves 45 and the through hole 46. Therefore, the lubricant present between the inner surface of the middle cover portion 3 and the hammer member 40A can act as a barrier (resistance), preventing the hammer member 40A from swinging easily around the cam pin 81, thus reducing the possibility of the impact mechanism 4 becoming locked.

[0103] The hammer member 40A shown in Figure 15 is provided with two grooves 45 and a through hole 46, but it is not essential to provide both grooves 45 and the through hole 46, and the number and shape of the connecting parts provided on the hammer member 40A can be changed as appropriate.

[0104] Furthermore, the hammer member 40B may also be provided with a communication section (for example, a groove 45 and a through hole 46) similar to that of the hammer member 40A, thereby reducing the possibility of the impact mechanism 4 becoming locked.

[0105] Furthermore, the hammer members 40A and 40B of the impact rotary tool 1 of Modification 1 or 2 may be provided with the communication portion (for example, the groove 45 and through hole 46) described in Modification 3, thereby reducing the possibility of the impact mechanism 4 locking up.

[0106] (3.4) Modification 4 The impact rotary tool 1 according to Modification 4 will be described with reference to Figure 16. Modification 4 differs from the basic configuration in that a recess 66 is provided in the middle cover portion 3 that faces the first groove 43 in a direction intersecting the axial direction of the output shaft 30. The impact rotary tool 1 according to Modification 4 has the same configuration as the basic configuration except for the provision of a recess 66 on the inner surface of the middle cover portion 3, so the same reference numerals are used for components common to the basic configuration, and their explanations are omitted.

[0107] In the impact rotary tool 1 of the modified example 4, recesses 66 are provided on the inner surface of the middle cover portion 3 near the cam pin 80 inserted into the first groove 43 of the hammer member 40A, and near the cam pin 81 inserted into the first groove 43 of the hammer member 40B. More specifically, recesses 66 are provided on the inner surfaces of the first cylindrical body 60 and the second cylindrical body 70, respectively, near the cam pin 80 and near the cam pin 81.

[0108] In the impact rotary tool 1 of the modified example 4, when the striking portion 42 of the hammer member 40B strikes the impacted portion 33 of the output shaft 30 in accordance with the rotation of the middle cover portion 3, the hammer member 40B swings around the cam pin 80, allowing the lubricant present between the inner surface of the middle cover portion 3 and the hammer member 40B to flow into the recess 66 provided near the cam pin 81. Therefore, the lubricant present between the inner surface of the middle cover portion 3 and the hammer member 40B can act as a wall (resistance), preventing the hammer member 40B from swinging easily around the cam pin 80, thus reducing the possibility of the impact mechanism 4 becoming locked.

[0109] Similarly, when the striking portion 42 of the hammer member 40A strikes the striking portion 32 of the output shaft 30 in response to the rotation of the middle cover portion 3, the hammer member 40A swings around the cam pin 81, allowing the lubricant present between the inner surface of the middle cover portion 3 and the hammer member 40A to flow into the recess 66 provided near the cam pin 80. Therefore, the lubricant present between the inner surface of the middle cover portion 3 and the hammer member 40A can act as a barrier (resistance), preventing the hammer member 40A from swinging easily around the cam pin 81, thus reducing the possibility of the impact mechanism 4 becoming locked.

[0110] Furthermore, the configuration of Modified Example 4 may be applied to the impact rotary tool 1 of Modified Examples 1 to 3, thereby reducing the possibility of the impact mechanism 4 locking up.

[0111] (3.5) Other variations The impact rotary tool 1 may also have an outer shell (not shown) that covers the outside of the main body case 2.

[0112] The impact rotary tool 1 in the basic configuration and modified example 1 is equipped with two hammer members 40A and 40B, but the number of hammer members may be one. In this case, the output shaft 30 only needs to have one part to be struck by the striking part of the hammer member.

[0113] The inner cover section 3 is composed of two members (a first cylindrical body 60 and a second cylindrical body 70), but the inner cover section 3 may be composed of a combination of three or more members. Similarly, the inner cover section 3A is composed of two members (a first cylindrical body 90 and a second cylindrical body 95), but the inner cover section 3A may be composed of a combination of three or more members.

[0114] In the basic configuration and modified example 1, the shaft body 31 of the output shaft 30 is made of a single member, but the output shaft 30 may also be made by connecting a first member provided with impact-receiving parts 32 and 33 and a second member provided with a connecting part 34.

[0115] (summary) Based on the embodiments described above, the following aspects are disclosed.

[0116] The impact rotary tool (1) in the first embodiment comprises a motor (10), an output shaft (30) to which a cutting tool (T1) can be attached, an impact mechanism (4), an inner cover section (3, 3A, 3B), and a main body case (2). The impact mechanism (4) applies an impact force to the output shaft (30) in accordance with the rotation of the motor (10). The main body case (2) houses the motor (10), the impact mechanism (4), and the inner cover section (3, 3A, 3B). The impact mechanism (4) has hammer members (40A, 40B) that strike the parts to be struck (32, 33) provided on the output shaft (30) in accordance with the rotation of the motor (10). The inner cover section (3, 3A, 3B) covers at least the impact mechanism (4).

[0117] In this embodiment, since the inner cover portion (3, 3A, 3B) housed in the main body case (2) covers the impact mechanism (4), the impact mechanism (4) can be double-covered by the inner cover portion (3, 3A, 3B) and the main body case (2). Therefore, when impact noise is generated when the hammer member (40A, 40B) strikes the part to be struck (32, 33), the impact noise transmitted to the outside of the main body case (2) can be reduced.

[0118] In the second embodiment of the impact rotary tool (1), as in the first embodiment, the middle cover (3) rotates in conjunction with the rotation of the motor (10)'s rotating shaft (11).

[0119] According to this embodiment, the rotation of the middle cover (3) converts the energy from the impact into inertial energy, thereby increasing the output torque.

[0120] In the third embodiment of the impact rotary tool (1), the middle cover portion (3A, 3B) is fixed to the main body case (2), as in the first embodiment.

[0121] In this embodiment, the load on the motor (10) can be reduced compared to the case where the middle cover portion (3A, 3B) rotates in conjunction with the rotation of the motor (10)'s rotating shaft (11).

[0122] In the fourth embodiment of the impact rotary tool (1), the middle cover portion (3, 3A, 3B) is constructed by combining multiple members, in any of the first to third embodiments.

[0123] According to this embodiment, the work of housing the impact mechanism (4) inside the middle cover portion (3, 3A, 3B) can be easily carried out.

[0124] The impact rotary tool (1) of the fifth embodiment further comprises a lubricant filled inside the middle cover portion (3, 3A, 3B) in any of the first to fourth embodiments.

[0125] According to this embodiment, the inner cover portion (3, 3A, 3B) covering the impact mechanism (4) suppresses the scattering of lubricant filled in the impact mechanism (4), thereby reducing the lubrication effect of the lubricant and suppressing the deterioration of the components constituting the impact mechanism (4).

[0126] In the sixth embodiment of the impact rotary tool (1), a sealing portion (100) is further provided for sealing the middle cover portion (3, 3A, 3B) as in the fifth embodiment.

[0127] According to this embodiment, leakage of the lubricant filled in the inner cover portion (3, 3A, 3B) to the outside of the inner cover portion (3, 3A, 3B) can be further reduced, and the decrease in the lubricating effect of the lubricant can be further suppressed.

[0128] In the seventh embodiment of the impact rotary tool (1), in the fifth or sixth embodiment, the hammer members (40A, 40B) are cylindrical and have an insertion hole (41) into which the output shaft (30) is inserted. The hammer members (40A, 40B) are provided with a connecting portion (45, 46) that connects the inner surface (411) and the outer surface (412) of the hammer members (40A, 40B).

[0129] According to this embodiment, when the hammer members (40A, 40B) strike the parts to be struck (32, 33), the lubricant present between the inner surface of the inner cover parts (3, 3A, 3B) and the hammer members (40A, 40B) can move through the connecting parts (45, 46). Therefore, there is an advantage in that the possibility of the lubricant present between the inner surface of the inner cover parts (3, 3A, 3B) and the hammer members (40A, 40B) hindering the movement of the hammer members (40A, 40B) can be reduced.

[0130] In the eighth embodiment of the impact rotary tool (1), in any of the fifth to seventh embodiments, the hammer members (40A, 40B) are provided with a first groove (43) and a second groove (44) into which two cam pins (80, 81) fixed to the middle cover portion (3, 3A, 3B) are respectively inserted. The width of the first groove (43) is greater than the diameter of the cam pins (80, 81). The hammer members (40A, 40B) are pivotable around the cam pins (80, 81) inserted in the second groove (44) within the range in which the cam pins (80, 81) can move within the groove of the first groove (43). On the inner surface of the middle cover portion (3, 3A, 3B), a recess (66) is provided in the portion facing the first groove (43) in a direction intersecting the axial direction of the output shaft (30).

[0131] According to this embodiment, when the hammer members (40A, 40B) strike the parts to be struck (32, 33), the lubricant present between the inner surface of the inner cover parts (3, 3A, 3B) and the hammer members (40A, 40B) can flow into the recess (66). Therefore, there is an advantage in that the lubricant present between the inner surface of the inner cover parts (3, 3A, 3B) and the hammer members (40A, 40B) can act as resistance and reduce the possibility of hindering the movement of the hammer members (40A, 40B).

[0132] In the ninth embodiment of the impact rotary tool (1), in any of the first to eighth embodiments, the output shaft (30) is provided with two impact targets (32, 33) positioned symmetrically with respect to the rotation center of the output shaft (30). The impact mechanism (4) has two hammer members (40A, 40B) corresponding to the two impact targets (32, 33). In accordance with the rotation of the motor (10), each of the two hammer members (40A, 40B) strikes the corresponding impact target (32, 33) of the two impact targets (32, 33).

[0133] According to this embodiment, the two hammer members (40A, 40B) strike the two striking parts (32, 33), thereby equally applying striking force to the two striking parts (32, 33) which are positioned symmetrically with respect to the rotation center of the output shaft (30). Therefore, the two hammer members (40A, 40B) strike the two striking parts (32, 33) of the output shaft (30), allowing the output shaft (30) to rotate smoothly.

[0134] The configurations relating to the second to ninth aspects are not essential to the impact rotary tool (1) and can be omitted as appropriate. [Explanation of Symbols]

[0135] 1. Impact rotary tool 2. Main unit case 3,3A,3B Middle cover section 4. Impact Mechanism 10 motors 11 Rotation axis 30 Output shaft 32,33 Hit part 40A, 40B Hammer component 45 Concave groove (communication part) 46 Through hole (communication part) 66 recesses 411 Inner surface 412 External surface T1 tip tool

Claims

1. Motor and, An output shaft to which a cutting tool can be attached, An impact mechanism that applies a striking force to the output shaft in accordance with the rotation of the motor, The inner cover section, The system comprises the motor, the impact mechanism, and a main body case that houses the middle cover portion, The impact mechanism has a hammer member that strikes a part to be struck on the output shaft in accordance with the rotation of the motor. The aforementioned middle cover portion covers at least the impact mechanism, Impact rotary tool.

2. The aforementioned middle cover rotates in conjunction with the rotation of the motor's rotating shaft. The impact rotary tool according to claim 1.

3. The aforementioned middle cover portion is fixed to the main body case. The impact rotary tool according to claim 1.

4. The aforementioned middle cover portion is composed of multiple members, The impact rotary tool according to claim 1.

5. The aforementioned middle cover portion is further equipped with a lubricant that is filled inside. The impact rotary tool according to claim 1.

6. The aforementioned middle cover portion is further provided with a sealing portion. The impact rotary tool according to claim 5.

7. The hammer member is cylindrical in shape and has an insertion hole into which the output shaft is inserted. The hammer member is provided with a communication portion that connects the inner surface and the outer surface of the hammer member. The impact rotary tool according to claim 5.

8. The hammer member is provided with a first groove and a second groove into which two cam pins fixed to the middle cover portion are respectively inserted. The width of the first groove is greater than the diameter of the cam pin. The hammer member is pivotable around the cam pin inserted in the second groove, within a range in which the cam pin can move within the groove of the first groove. On the inner surface of the middle cover portion, a recess is provided in a direction intersecting the axial direction of the output shaft, in a portion facing the first groove. The impact rotary tool according to claim 5.

9. The output shaft is provided with two impact targets positioned symmetrically with respect to the rotation center of the output shaft. The impact mechanism has two hammer members corresponding to the two parts to be struck, In accordance with the rotation of the motor, each of the two hammer members strikes the corresponding part of the two parts to be struck. An impact rotary tool according to any one of claims 1 to 8.

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