Impact rotary tools

Abstract

To provide an impact rotary tool that can reduce impact noise. [Solution] The impact rotary tool 1 comprises a motor 10, an output shaft 30, a striking part 48, a reduction mechanism 6, and an impact mechanism 4. The motor 10 rotates the rotation shaft 11. A tip tool T1 can be attached to the output shaft 30. The striking part 48 rotates integrally with the output shaft 30. The reduction mechanism 6 reduces the rotation of the rotation shaft 11 and transmits it to the output shaft 30. The impact mechanism 4 has a hammer member 40 that rotates in accordance with the rotation of the rotation shaft 11 and strikes the striking part 48. The impact mechanism 4 is positioned between the reduction mechanism 6 and the motor 10.

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 cylindrical 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 a first claw is provided in the rear part. The main hammer is fitted on the outer periphery of the spindle, and a second claw that engages with the first claw is provided in the front part. 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 into the internal space of this 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 the 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, a striking part, a reduction mechanism, and an impact mechanism. The motor rotates the rotation shaft. A tip tool can be attached to the output shaft. The striking part rotates integrally with the output shaft. The reduction mechanism reduces the rotation of the rotation shaft and transmits it to the output shaft. The impact mechanism has a hammer member that rotates in accordance with the rotation of the rotation shaft and strikes the striking part. The impact mechanism is positioned between the reduction mechanism and the motor. [Effects of the Invention]

[0008] According to this disclosure, it is possible 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 a side view of the same impact rotary tool. [Figure 3] Figure 3 is an exploded perspective view of the same impact rotary tool. [Figure 4] Figure 4 is an exploded perspective view of the main components of the impact rotary tool shown above. [Figure 5] Figure 5 is a cross-sectional view of the main part of the impact rotary tool shown above. [Figure 6] Figure 6 is a cross-sectional view taken along the line A1-A2 in Figure 2. [Figure 7] Figure 7 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 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 a perspective view of the hammer member provided in the impact rotary tool of Modification 3. [Figure 15] FIG. 15 is a cross-sectional view of the 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 drawing described in the following embodiment is a schematic drawing, and the dimensional ratios such as the sizes of each component 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 the main part of the impact rotary tool 1 of the present embodiment. FIG. 2 is a side view of the impact rotary tool 1. FIG. 3 is an exploded perspective 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, a struck portion 48, a speed reduction mechanism 6, and an impact mechanism 4.

[0013] The motor 10 rotates the rotating shaft 11.

[0014] A tip tool T1 can be attached to the output shaft 30.

[0015] The struck portion 48 rotates integrally with the output shaft 30.

[0016] The speed reduction mechanism 6 reduces the rotation of the rotating shaft 11 and transmits it to the output shaft 30.

[0017] The impact mechanism 4 has a hammer member 40 that rotates in response to the rotation of the rotating shaft 11 and strikes the struck portion 48.

[0018] The impact mechanism 4 is disposed between the speed reduction mechanism 6 and the motor 10.

[0019] Here, the tip tool T1 being attached 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. 2, the illustration of the tip tool T1 is omitted, and the tip tool T1 is shown by a two-dot chain line. Also, the struck portion 48 rotating integrally with the output shaft 30 means that the struck portion 48 rotates at the same rotational speed as the output shaft 30 with the output shaft 30 as the rotation axis.

[0020] In the impact rotary tool 1 of the present embodiment, since the speed reduction mechanism 6 reduces the rotation of the rotating shaft 11 of the motor 10 and transmits it to the output shaft 30, the struck portion 48 also rotates at a speed reduced by the speed reduction mechanism 6. And the hammer member 40 strikes the struck portion 48 by rotating in response to the rotation of the rotating shaft 11, thereby rotating the output shaft 30. Here, since the struck portion 48 rotates at a speed reduced by the speed reduction mechanism 6, the impact force applied to the struck portion 48 can be reduced compared to the case where the stationary struck portion 48 is struck by the hammer member 40, and an impact rotary tool 1 capable of reducing the striking sound can be provided.

[0021] (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 of the impact rotary tool 1) 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.

[0022] (2.1) Configuration The impact rotary tool 1 of this embodiment is a portable power 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.

[0023] The impact rotary tool 1 of this embodiment comprises, as described above, a motor 10, an output shaft 30, a striking part 48, a reduction mechanism 6, and an impact mechanism 4. The impact rotary tool 1 further comprises a main body case 2 and an inner cover part 3. The main body case 2 houses the motor 10, the output shaft 30, the striking part 48, the reduction mechanism 6, and the impact mechanism 4. The inner cover part 3 is housed in the main body case 2 and covers the reduction mechanism 6 and the impact mechanism 4. In other words, the inner cover part 3 houses the reduction mechanism 6 and the impact mechanism 4.

[0024] (2.1.1) Main unit case The main case 2 houses the motor 10, output shaft 30, impact-receiving part 48, impact mechanism 4, reduction mechanism 6, and inner cover part 3 (see Figures 2 and 3). The main case 2 also houses the control circuit 5 (see Figure 2), etc.

[0025] As shown in Figure 3, the main case 2 is constructed by combining the right case 21, the left case 22, and the front case 23. When the right case 21, the left case 22, and the front case 23 are combined, the main case 2 has a storage section 2A, a grip section 2B, and a mounting section 2C (see Figure 2).

[0026] 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, impact mechanism 4, reduction mechanism 6, and 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 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.

[0027] 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 Figures 2 and 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.

[0028] 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.

[0029] 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.

[0030] (2.1.2) Motor The motor 10 is housed in the housing section 2A (more specifically, the first housing chamber 2E) of the main body 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. The tip of the rotating shaft 11 is provided with, for example, a keyway (not shown).

[0031] The torque and rotational speed of the motor 10 are controlled, for example, by a control circuit 5 (see Figure 2). The control circuit 5 is housed, for example, in the grip section 2B.

[0032] 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.

[0033] (2.1.3) Output shaft The output shaft 30 has a cylindrical shaft body 31 made of, for example, a metal material with the front-to-back direction as its 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.

[0034] A cutting tool T1 is attached to the connecting portion 34 of the output shaft 30. The cutting 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. From among the various types of cutting tools T1, the cutting tool T1 appropriate for the application is attached to the output shaft 30.

[0035] Furthermore, 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 the holder member.

[0036] The rear of the shaft 31 is connected to the sun gear 61 of the reduction mechanism 6, and the shaft 31 rotates together with the sun gear 61.

[0037] (2.1.4) Reduction mechanism and middle cover section The reduction gear 6 is housed in the housing section 2A (more specifically, the second housing chamber 2F) of the main case 2. The reduction gear 6 comprises a sun gear 61, a plurality of planetary gears 62 (for example, six in the example of Figure 5), an internal gear 63, a planetary carrier 45, a shaft holding member 49, and a cover body 70.

[0038] The sun gear 61 is connected to the rear end of the output shaft 30. The axis of the sun gear 61 and the axis of the output shaft 30 coincide, and the sun gear 61 and the output shaft 30 rotate as a single unit. A round hole 611 is provided on the rear end face of the sun gear 61, and a shaft 36 for centering is inserted into the round hole 611 (see Figure 1).

[0039] Multiple planetary gears 62 are arranged around the sun gear 61. The multiple planetary gears 62 are arranged at equal intervals on the circumference of the sun gear 61 with respect to its central axis. The planetary gears 62 are external gears. Each of the multiple planetary gears 62 meshes with the sun gear 61 and the internal gear 63.

[0040] The internal gear 63 is provided on the inner circumferential surface of the cylindrical portion 60, which has a thickness smaller than its diameter. Multiple planetary gears 62 are arranged on the inner circumferential surface of the cylindrical portion 60. The internal gear 63 is positioned to surround the multiple planetary gears 62 and meshes with them. The cylindrical portion 60 is provided with two through holes 64, positioned symmetrically with respect to the central axis of the cylindrical portion 60, into which the front ends of two cam pins 80, 81 (described later) are inserted.

[0041] The planetary carrier 45 and the shaft holding member 49 support multiple planetary gears 62 so that they can rotate. Each of the multiple planetary gears 62 is supported between the planetary carrier 45 and the shaft holding member 49 in a state that allows it to rotate about the shaft 621.

[0042] The planetary carrier 45 is positioned behind the cylindrical portion 60, which is equipped with an internal gear 63. The planetary carrier 45 has a disc-shaped rotating plate 46. Multiple shaft holes are provided on the front surface of the rotating plate 46, into which the shafts 621 of multiple planetary gears 62 are each inserted. A cylindrical tube portion 47 is provided in the center of the rear surface of the rotating plate 46. The tip of a shaft 36 inserted into a hole in the tube portion 47 is inserted into a round hole 611 of the sun gear 61, and the shaft 36 aligns the sun gear 61 with the planetary carrier 45. In addition, a striking portion 48 that protrudes radially from the circumferential surface of the tube portion 47 is provided integrally with the rotating plate 46 and the tube portion 47. The shape of the striking portion 48 when viewed from the rear is, for example, a fan shape.

[0043] The shaft holding member 49 is positioned in front of the internal gear 63. The shaft holding member 49 has a disc-shaped rotating plate 490. A cylindrical portion 491 that protrudes forward is provided at the center of the front surface of the rotating plate 490. The shaft body 31 of the output shaft 30 is inserted into the hole in the cylindrical portion 491.

[0044] In this configuration, a planetary carrier 45 is positioned behind the cylindrical portion 60 on which the internal gear 63 is located, and a shaft holding member 49 is positioned in front of the cylindrical portion 60. Multiple planetary gears 62 are rotatably supported between the planetary carrier 45 and the shaft holding member 49.

[0045] A cover body 70 is attached to the rear side of the cylindrical portion 60, where the internal gear 63 is located, so as to cover the planetary carrier 45. The cylindrical portion 60 and the cover body 70 are joined together using fastening members such as screws, but the method of joining the cylindrical portion 60 and the cover body 70 can be changed as appropriate.

[0046] The cover body 70 has a cylindrical section 71 and a disc-shaped rear wall 72 that closes the rear end of the section 71. A cylindrical section 73 projecting rearward is provided at the center of the rear surface of the rear wall 72. A through hole 74 is provided at the center of the section 73, penetrating the section 73 in the front-rear direction. A keyway 75 is provided on the inner circumferential surface of the through hole 74. A key is inserted into the keyway 75 on the inner circumferential surface of the through hole 74 and into a keyway provided on the rotating shaft 11 of the motor 10, so that the rotating shaft 11 and the cover body 70 rotate together. In addition, two through holes 76 are provided in the rear wall 72 at positions symmetrical with respect to the central axis of the section 73. The rear ends of two cam pins 80 and 81 are inserted into the two through holes 76.

[0047] Since the cover body 70 is attached to the rear side of the cylindrical portion 60 on which the internal gear 63 is provided, the cover body 70 and the cylindrical portion 60 rotate together with the rotation shaft 11.

[0048] As the cylindrical portion 60 rotates, the internal gear 63 rotates, and the rotation of the planetary gears 62 is transmitted to the sun gear 61, causing the sun gear 61 to rotate. In addition, as the multiple planetary gears 62 revolve around the sun gear 61, the multiple planetary gears 62, the planetary carrier 45, and the shaft holding member 49 rotate around the sun gear 61.

[0049] Here, the space enclosed by the cover body 70, the cylindrical portion 60, and the shaft holding member 49 houses the sun gear 61 and multiple planetary gears 62 that constitute the reduction mechanism 6, and the impacted portion 48, hammer member 40, and cam pins 80, 81 that constitute the impact mechanism 4. In other words, the cylindrical portion 60, the shaft holding member 49, and the cover body 70 constitute the middle cover portion 3 that houses the reduction mechanism 6 and the impact mechanism 4. Since the cylindrical portion 60 rotates in accordance with the rotation of the rotating shaft 11 of the motor 10, the middle cover portion 3 rotates in conjunction with the rotation of the rotating shaft 11. As the middle cover portion 3 rotates, the energy from the impact can be converted into inertial energy, thereby increasing the output torque.

[0050] In this embodiment, the inner cover portion 3 is constructed by combining multiple components. The inner cover portion 3 is formed in a cylindrical shape overall. In this embodiment, the inner cover portion 3 is constructed by combining multiple components, namely the cylindrical portion 60, the shaft holding member 49, and the cover body 70. Since the inner cover portion 3 is constructed by combining multiple components, it is easy to house the impact mechanism 4 and the deceleration mechanism 6 inside the inner cover portion 3. The cylindrical portion 60 is fastened and fixed to the cover body 70 using fastening members such as screws.

[0051] 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 area between the impacted portion 48 and the hammer member 40. By filling the contact area between the impacted portion 48 and the hammer member 40 with lubricant, the occurrence of wear due to impact can be reduced. In addition, the lubricant is also filled at the contact areas of the sun gear 61, the multiple planetary gears 62, and the internal gear 63 that constitute the reduction mechanism 6. By filling the contact areas of the sun gear 61, the multiple planetary gears 62, and the internal gear 63 with lubricant, wear of the gears 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.

[0052] (2.1.5) 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 applies an impact force to the output shaft 30 by striking the part to be struck 48, which rotates integrally with the output shaft 30.

[0053] The impact mechanism 4 comprises a hammer member 40, two cam pins 80 and 81, and the cover body 70 described above. The impact mechanism 4 further comprises a striking part 48 that rotates integrally with the output shaft 30. The impact mechanism 4 is positioned between the reduction mechanism 6 and the motor 10. More specifically, as shown in Figure 5, the impact mechanism 4 and the reduction mechanism 6 are positioned adjacent to each other. Here, "positioned adjacent to each other" means that there are no other parts interposed between the parts constituting the impact mechanism 4 and the parts constituting the reduction mechanism 6. Because the impact rotary tool 1 of this embodiment has the impact mechanism 4 and the reduction mechanism 6 adjacent to each other, it can be made smaller compared to the case where another part is interposed between the impact mechanism 4 and the reduction mechanism 6. One or more other parts may be interposed between the parts constituting the impact mechanism 4 and the parts constituting the reduction mechanism 6.

[0054] The front ends of the cam pins 80 and 81 are inserted into two through holes 64 in the cylindrical portion 60 where the internal gear 63 is located. The rear ends of the cam pins 80 and 81 are inserted into two through holes 76 in the rear wall 72 of the cover body 70.

[0055] The hammer member 40 is formed in an oval shape when viewed from the front, and has an insertion hole 41 in the center into which the cylindrical portion 47, which is provided with the striking portion 48, is inserted. The hammer member 40 is cylindrical with an insertion hole 41 into which the striking portion 48 is inserted.

[0056] On the outer circumferential surface of the hammer member 40, a first groove 43 into which a cam pin 81 is inserted and a second groove 44 into which a cam pin 80 is inserted are provided, positioned opposite each other with the insertion hole 41 in between. The width of the first groove 43 is wider than the diameter of the cam pin 81, and 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.

[0057] As shown in Figures 4 and 6, the hammer member 40 is housed inside the inner cover portion 3 such that the cam pin 81 is inserted into the first groove 43 and the cam pin 80 is inserted into the second groove 44. In other words, the hammer member 40 is provided with a first groove 43 and a second groove 44 into which the two cam pins 80 and 81 fixed to the inner cover portion 3 are inserted, and the width of the first groove 43 is greater than the diameter of the cam pin 81.

[0058] Since the cover body 70 is connected to the rotating shaft 11 of the motor 10, the cover body 70 rotates in accordance with the rotation of the rotating shaft 11. Since the hammer member 40 is supported between two cam pins 80 and 81 installed between the cover body 70 and the cylindrical part 60, when the cover body 70 and the cylindrical part 60 rotate in accordance with the rotation of the rotating shaft 11, the hammer member 40 also rotates. In other words, the hammer member 40 rotates in accordance with the rotation of the rotating shaft 11. The hammer member 40 is capable of rotating (oscillating) around the cam pin 80 inserted into the second groove 44, within the range in which the cam pin 81 can move within the first groove 43.

[0059] Furthermore, as the cylindrical portion 60 rotates, the multiple planetary gears 62 that mesh with the internal gear 63 provided on the cylindrical portion 60 rotate around the sun gear 61, and the planetary carrier 45, on which the striking portion 48 is provided, rotates in accordance with the revolution of the multiple planetary gears 62. Here, the rotational speed of the planetary carrier 45 is the speed obtained by reducing the rotational speed of the cylindrical portion 60 by the reduction ratio of the reduction mechanism 6, so the rotational speed of the hammer member 40 becomes relatively faster than the rotational speed of the striking portion 48. In other words, since the hammer member 40 rotates at a relatively faster speed than the striking portion 48, the striking portion 48 is struck by the striking portion 42 of the hammer member 40.

[0060] (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, reduction mechanism 6, inner cover 3, and control circuit 5, among other components.

[0061] Here, the impact mechanism 4, the reduction mechanism 6, and the middle 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.

[0062] For example, the assembly worker places multiple planetary gears 62 and a sun gear 61 inside the internal gear 63 provided in the cylindrical section 60. The assembly worker places a shaft holding member 49 on the front side of the cylindrical section 60 and a planetary carrier 45 on the rear side of the cylindrical section 60, supporting each of the multiple planetary gears 62 between the shaft holding member 49 and the planetary carrier 45 in a state where it can rotate. The assembly worker then inserts a shaft 36 from the rear into the hole in the cylindrical section 47 of the planetary carrier 45 to align the central axes of the sun gear 61, the output shaft 30, and the planetary carrier 45. The rear end of the shaft 36 is provided with a large-diameter section 37, which has a larger diameter than the rest of the shaft 36, and the shaft 36 is inserted into the hole in the cylindrical section 47 until the large-diameter section 37 reaches the rear end of the cylindrical section 47 (see Figure 4).

[0063] Next, the assembler inserts the cam pins 80 and 81 into the two through holes 64 of the cylindrical portion 60, respectively, so that the cam pin 81 is inserted into the first groove 43 and the cam pin 80 is inserted into the second groove 44, thereby holding the hammer member 40 between the two cam pins 80 and 81. Then, the assembler fills the inside of the cylindrical portion 60 and the cover body 70 with lubricant and attaches the cover body 70 to the rear side of the cylindrical portion 60, thereby joining the cylindrical portion 60 and the cover body 70. At this point, the cylindrical portion 60, the cover body 70 and the shaft holding member 49 constitute the middle cover portion 3, and the impact mechanism 4 and the reduction mechanism 6, etc., are housed inside the middle cover portion 3.

[0064] Next, the assembly worker inserts the rotating shaft 11 of the motor 10 into the through hole 74 of the cover body 70, and inserts a key into the keyway 75 provided on the inner surface of the through hole 74 and the keyway provided on the rotating shaft 11, thereby connecting the rotating shaft 11 and the cover body 70. The assembly worker also connects the output shaft 30 to the sun gear 61 of the reduction mechanism 6.

[0065] The assembler then 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 impact mechanism 4 and the reduction mechanism 6, 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. The assembler then places the front case 23 on top of the right case 21 and the left case 22 so as to close the openings that are formed 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 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 3) 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 3) is attached to the output shaft 30, and the output shaft 30 is rotatably supported by the front case 23 via the bearing 82.

[0066] 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.

[0067] (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 axis 11 of the motor 10 rotates counterclockwise when viewed from the front, the cover body 70 and the cylindrical section 60 rotate counterclockwise when viewed from the front in accordance with the rotation of the rotation axis 11. Since the cam pins 81 and 80, which are installed between the cover body 70 and the cylindrical section 60, are inserted into the first groove 43 and the second groove 44 of the hammer member 40, the hammer member 40 rotates in accordance with the rotation of the cover body 70 and the cylindrical section 60.

[0068] Furthermore, since the multiple planetary gears 62 constituting the reduction mechanism 6 mesh with the internal gear 63 and sun gear 61 provided on the cylindrical part 60, when the internal gear 63 rotates, the multiple planetary gears 62 rotate on their own axes and revolve around the sun gear 61, causing the sun gear 61 to rotate. As a result, the output shaft 30 connected to the sun gear 61 rotates at a rotational speed reduced by the reduction ratio of the reduction mechanism 6 from the rotational speed of the motor 10's rotating shaft 11. Also, as the multiple planetary gears 62 revolve around the sun gear 61, the planetary carrier 45, on which the impacted part 48 is provided, rotates. Here, the rotational speed of the planetary carrier 45 is slower than the rotational speed of the motor 10's rotating shaft 11 because it is reduced by the reduction mechanism 6. Therefore, the rotational speed of the hammer member 40 is faster than the rotational speed of the planetary carrier 45, and as the hammer member 40 rotates relative to the planetary carrier 45, the impacted part 42 on the left side of the hammer member 40 collides with the impacted part 48. Here, the hammer member 40 is pivotable around the cam pin 80 inserted in the second groove 44, within the range in which the cam pin 81 can move within the first groove 43. Therefore, the hammer member 40 pivots in one direction around the cam pin 80 inserted in the second groove 44 until the cam pin 81 moves to the end of the first groove 43. Subsequently, as the hammer member 40 rotates further counterclockwise in response to the rotation of the cover body 70, the striking part 42 passes over the struck part 48, and the inner circumferential surface of the insertion hole 41 is pressed against the struck part 48, causing the hammer member 40 to pivot in the opposite direction to the above-mentioned one direction, with the cam pin 80 inserted in the second groove 44 as the pivot.

[0069] In this way, as the cylindrical part 60 and the cover body 70 rotate in accordance with the rotation of the rotating shaft 11 of the motor 10, the rotational speed of the rotating shaft 11 is reduced by the reduction mechanism 6 and transmitted to the output shaft 30, and the output shaft 30 rotates at the rotational speed reduced by the reduction mechanism 6. In addition, as the cylindrical part 60 and the cover body 70 rotate, the striking part 42 of the hammer member 40 strikes the part to be struck 48, thereby applying an impact force to the output shaft 30. This makes it possible to realize a high-torque impact rotary tool 1, and the tip tool T1 held on the output shaft 30 is used to perform the work of tightening or loosening fastening members.

[0070] Furthermore, if the rotation shaft 11 of the motor 10 rotates clockwise when viewed from the front, the part to be struck 48 will be struck by a different striking part 42 of the hammer member 40 than the striking part 42 that strikes the part to be struck 48 when the rotation shaft 11 rotates counterclockwise when viewed from the front.

[0071] (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.

[0072] 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.

[0073] (3.1) Variation 1 The impact rotary tool 1 according to Modification 1 will be described with reference to Figure 7.

[0074] The impact rotary tool 1 of Modified Example 1 differs from the basic configuration of the impact rotary tool 1 in that two impacted parts 48A and 48B are provided on the cylindrical portion 47 of the planetary carrier 45, and the impact mechanism 4 comprises two hammer members 40A and 40B and a cam case 50. Furthermore, the impact rotary tool 1 of Modified Example 1 also differs from the basic configuration of the impact rotary tool 1 in that the middle cover portion 3A that covers the impact mechanism 4 and the reduction mechanism 6 is fixed to the main body case 2. In the impact rotary tool 1 of Modified Example 1, components common to the basic configuration are given the same reference numerals, and their descriptions are omitted.

[0075] 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 cylindrical portion 47 of the planetary carrier 45, and a pair of second plate pieces 53, 53 that connect the ends of the pair of first plate pieces 51, 52.

[0076] The pair of first plate pieces 51 and 52 are formed in a rectangular plate shape.

[0077] The first plate piece 51 has a through hole 56 in the center of its longitudinal direction into which the cylindrical portion 47 of the planetary carrier 45 is inserted, and two through holes 54 are provided symmetrically with respect to the center of the through hole 56. The first ends (front ends) of the 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.

[0078] The first plate piece 52 has a through hole 57 in the center of its longitudinal direction into which the cylindrical portion 47 of the planetary carrier 45 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 the 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.

[0079] 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. Furthermore, the rear striking portion 48A is inserted into the insertion hole 41 of the hammer member 40A, and the front striking portion 48B is inserted into the insertion hole 41 of the hammer member 40B.

[0080] An internal gear is provided at the rear of the through hole 57 of 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. The cam case 50 is connected to the cylindrical part 60 described in the basic configuration. When the cylindrical part 60 rotates in accordance with the rotation of the cam case 50, the output shaft 30 rotates after being decelerated by the reduction mechanism 6, and the planetary carrier 45, which is provided with the impacted parts 48A and 48B, rotates. Furthermore, when the cam case 50 rotates, the hammer members 40A and 40B supported by the cam case 50 rotate, the impacting part 42 of the hammer member 40A strikes the impacted part 48A, and the impacting part 42 of the hammer member 40B strikes the impacted part 48B of the output shaft 30. In this way, the rotation of the motor shaft 11 of the motor 10 is transmitted to the output shaft 30 by the reduction mechanism 6, causing the output shaft 30 to rotate, and at the same time, an impact force is applied to the output shaft 30 by the impact mechanism 4, thereby realizing a high-torque impact rotary tool 1.

[0081] Furthermore, in the basic configuration, the components constituting the middle cover 3 are shared with the components of the reduction mechanism 6 and the impact mechanism 4. However, the impact rotary tool 1 of the modified example 1 is equipped with a middle cover 3A that is constructed as a separate component from the reduction mechanism 6 and the impact mechanism 4.

[0082] The middle cover section 3A is composed of a front first cylindrical body 90 and a rear 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 areas between the impacted parts 48A, 48B and the hammer members 40A, 40B. The lubricant is also filled into the contact areas of the sun gear 61, the multiple planetary gears 62, and the internal gear 63 that constitute the reduction mechanism 6. By filling the contact areas between the impacted parts 48A, 48B and the hammer members 40A, 40B with lubricant, wear caused by impact can be reduced. In addition, by filling the contact areas of the sun gear 61, the multiple planetary gears 62, and the internal gear 63 with lubricant, wear of the gears can be reduced.

[0083] The first cylindrical body 90 is formed in a closed-bottom cylindrical shape with a hollow cylindrical portion 91 and a disc-shaped front wall 92 that closes the front end of the cylindrical portion 91. A through hole 93 into which the output shaft 30 is inserted is provided at the center of the front wall 92.

[0084] The second cylindrical body 95 is formed as a bottomed cylindrical body with a hollow cylindrical portion 96 and a disc-shaped rear wall 97 that closes the rear end of the cylindrical portion 96. A round hole 98 is provided in the center of the rear wall 97 for passing the rotating shaft 11 of the motor 10.

[0085] The middle cover section 3A is fixed to the main body case 2. More specifically, the middle cover section 3A is fixed to the main body case 2 in an appropriate manner while housing the hammer members 40A, 40B, the cam case 50, the cam pins 80, 81, the impacted parts 48A, 48B provided on the planetary carrier 45, and the reduction mechanism 6. 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 the case where the middle cover section 3 rotates in conjunction with the rotation shaft 11 of the motor 10. The cam case 50 is housed in 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. The cylindrical section 60 is also housed in 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.

[0086] Here, the two impacted parts 48A and 48B are positioned symmetrically with respect to the rotation center of the output shaft 30 (i.e., the central axis of the cylindrical part 47). The impact mechanism 4 has two hammer members 40A and 40B, each corresponding to the two impacted parts 48A and 48B. In accordance with the rotation of the motor 10, each of the two hammer members 40A and 40B strikes the corresponding impacted part 48A or 48B of the two impacted parts 48A and 48B.

[0087] More specifically, the cylindrical portion 47 of the planetary carrier 45 is provided with two impact targets 48A and 48B arranged side by side in the front-to-back direction. The two impact targets 48A and 48B protrude from the surface of the cylindrical portion 47 in opposite directions. Impact target 48A is located on the rear side of the surface of the cylindrical portion 47, and impact target 48B is located on the front side of the surface of the cylindrical portion 47.

[0088] Since the two hammer members 40A and 40B have a similar shape to the hammer member 40 described in the basic configuration, the description of hammer members 40A and 40B will be omitted.

[0089] The two hammer members 40A and 40B are arranged side by side in the front-to-back direction such that hammer member 40A is located behind hammer member 40B.

[0090] The rear hammer member 40A is supported by the cam case 50 with a cam pin 80 inserted into the first groove 43 and another cam pin 80 inserted into the second groove 44.

[0091] The front hammer member 40B is supported by the cam case 50 with the cam pin 81 inserted into the first groove 43 and the cam pin 80 inserted into the second groove 44.

[0092] In Modification 1, the two hammer members 40A and 40B strike the two striking parts 48A and 48B, thereby evenly applying striking force to the two striking parts 48A and 48B, which are positioned symmetrically with respect to the rotation center of the cylindrical part 47 of the planetary carrier 45. Therefore, the two hammer members 40A and 40B strike the two striking parts 48A and 48B, thereby evenly applying striking force to the output shaft 30 connected to the sun gear 61, and allowing the output shaft 30 to rotate smoothly.

[0093] Furthermore, since the striking portions 42 of the two hammer members 40A and 40B strike the target portions 48A and 48B, which are positioned symmetrically with respect to the rotation center of the output shaft 30, at the same timing, 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 48A and the timing at which the striking portion 42 of hammer member 40B strikes the target portion 48B are not necessarily to be exactly the same timing. The time difference between the timing at which the striking portion 42 of hammer member 40A strikes the target portion 48A and the timing at which the striking portion 42 of hammer member 40B strikes the target portion 48B is sufficient if it is 10% or less of the rotation period of the middle cover portion 3.

[0094] Furthermore, 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 48A and 48B, 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 the lubrication of the impact mechanism 4 and the reduction mechanism 6, the inner cover portion 3A can suppress the scattering of lubricant, so the lubricating effect of the lubricant is less likely to decrease. Therefore, in the impact rotary tool 1 of the modified example 1, wear of the parts constituting the impact mechanism 4 and the reduction mechanism 6 can be suppressed.

[0095] 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 load on 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.

[0096] In addition, in the basic configuration of the impact rotary tool 1, similar to the modified example 1, the output shaft 30 may be provided with two impacted parts 48A and 48B, and two hammer members 40A and 40B which strike the two impacted parts 48A and 48B, respectively.

[0097] Furthermore, in the basic configuration of the impact rotary tool 1, the middle cover portion 3A that covers the reduction mechanism 6 and the impact mechanism 4 may be fixed to the main body case 2, similar to the modified example 1.

[0098] (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 3. 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 3 includes the sealing part 100. Therefore, the same reference numerals are used for components common to both the basic and basic configurations, and their descriptions are omitted.

[0099] In this disclosure, "sealing" the inner cover portion 3 is not limited to airtight sealing of the inner cover portion 3, but may also include closing any gaps in the inner cover portion 3 so that the gaps in the inner cover portion 3 become smaller.

[0100] The middle cover portion 3 of the impact rotary tool 1 according to the modified example 2 comprises, as described in the basic configuration, a cylindrical portion 60, a shaft holding member 49 attached to the front side of the cylindrical portion 60, and a cover body 70 attached to the rear side of the cylindrical portion 60.

[0101] In the middle cover section 3 shown in Figures 8 and 9, the cylindrical section 60 and the cover body 70 are fixed together by three screws 200. For example, the cover body 70 is provided with three through holes 77 that pass through the cover body 70 in the front-to-back direction. The cylindrical section 60 is provided with three screw holes 67 at positions corresponding to the three through holes 77 of the cover body 70. The cylindrical section 60 and the cover body 70 are joined by screwing the screws 200 inserted into the through holes 77 of the cover body 70 into the screw holes 67 of the cylindrical section 60. The shaft holding member 49 is fixed to the middle cover section 3 or the main body case 2 that houses the middle cover section 3 by an appropriate method.

[0102] Here, the rotating shaft 11 of the motor 10 is inserted into the cylindrical portion 73 of the cover body 70, and an oil seal 101 is arranged inside the cylindrical portion 73 as a sealing portion 100 to close the gap between the rotating shaft 11, which performs rotational motion, and the cover body 70.

[0103] Furthermore, a groove 78 is provided on the surface of the cover body 70 facing the cylindrical portion 60 to accommodate the O-ring 102 which serves as the sealing portion 100.

[0104] Furthermore, on the surface of the cylindrical portion 60 facing the cover body 70, a groove 601 is provided in the area facing the bearing 120 located inside the cover body 70 to accommodate an O-ring 103 which serves as a sealing portion 100. On the surface of the cylindrical portion 60 facing the shaft holding member 49, a groove 602 is provided to accommodate an O-ring 104 which serves as a sealing portion 100.

[0105] Furthermore, a cylindrical portion 491 protruding forward is provided at the center of the front surface of the shaft holding member 49, and the shaft body 31 of the output shaft 30 is inserted into the hole in the cylindrical portion 491. A stepped portion 492 is provided on the inner surface of the cylindrical portion 491, on which an O-ring 105 serving as a sealing portion 100 is positioned.

[0106] When the inner cover portion 3 is assembled, the gap between the rotating shaft 11 of the motor 10 and the cylindrical portion 73 of the cover body 70 is sealed by the oil seal 101. The gap between the cover body 70 and the cylindrical portion 60 is sealed by O-rings 102 and 103. The gap between the cylindrical portion 60 and the shaft holding member 49 is sealed by O-ring 104. The gap between the cylindrical portion 491 of the shaft holding member 49 and the output shaft 30 is sealed by O-ring 105. In this way, the gaps in the inner cover portion 3 are sealed by the sealing portion 100, so that the lubricant filled in the inner cover portion 3 is less likely to leak out of the inner cover portion 3, and the decrease in the lubricating effect of the lubricant can be further suppressed. In this case, in the inner cover portion 3 shown in Figures 8 and 9, the sealing portion 100 is composed of the oil seal 101 and O-rings 102 to 105.

[0107] Furthermore, the sealing portion 100 is not limited to being composed of an oil seal 101 and O-rings 102 to 105, and the number and type of sealing members constituting the sealing portion 100 can be changed as appropriate.

[0108] In the middle cover section 3 shown in Figures 8 and 9, the cylindrical section 60 and the cover body 70 are joined by screw fastening using screws 200, but the method of joining the cylindrical section 60 and the cover body 70 is not limited to the above method.

[0109] For example, as shown in Figures 10 and 11, the cylindrical portion 60A and the cover body 70A may be joined by a retaining ring 201. The inner cover portion 3 shown in Figures 10 and 11 has the same configuration as the inner cover portion 3 shown in Figures 8 and 9, except that the cylindrical portion 60A and the cover body 70A are joined by a retaining ring 201, and the same reference numerals are used for common components, and their explanation is omitted.

[0110] In the central cover portion 3 shown in Figures 10 and 11, a hollow cylindrical cover portion 603 is provided integrally with the cylindrical portion 60A, protruding rearward from the outer circumference of the rear surface of the cylindrical portion 60A, and the cover body 70A is inserted into the interior of the cover portion 603.

[0111] On the inner surface of the cover portion 603, a groove 604 is provided, slightly behind the rear surface of the cover body 70A which is inserted into the interior of the cover portion 603, into which the retaining ring 201 is inserted.

[0112] In this inner cover section 3, with the cover body 70A inserted inside the cover section 603 of the cylindrical section 60A, the retaining ring 201 is fitted into the groove 604. In this state, the cover body 70A is sandwiched between the rear surface of the cylindrical section 60A and the retaining ring 201, thereby joining the cylindrical section 60A and the cover body 70A.

[0113] When the middle cover section 3 is assembled, the gap between the rotating shaft 11 of the motor 10 and the cylindrical portion 73 of the cover body 70A is sealed by the oil seal 101. The gap between the cover body 70A and the cylindrical portion 60A is sealed by O-rings 102 and 103. The gap between the cylindrical portion 60A and the shaft holding member 49 is sealed by O-ring 104. The gap between the cylindrical portion 491 of the shaft holding member 49 and the output shaft 30 is sealed by O-ring 105. In this way, the gaps in the middle cover section 3 are sealed by the sealing portion 100, making it difficult for the lubricant filled in the middle cover section 3 to leak out of the middle cover section 3, and further suppressing the decrease in the lubricating effect of the lubricant. In this case, in the middle cover section 3 shown in Figures 10 and 11, the sealing portion 100 is composed of the oil seal 101 and O-rings 102 to 105.

[0114] Furthermore, the sealing portion 100 is not limited to being composed of an oil seal 101 and O-rings 102 to 105, and the number and type of sealing members constituting the sealing portion 100 can be changed as appropriate.

[0115] Furthermore, as shown in Figures 12 and 13, the cylindrical portion 60B and the cover body 70B may be joined by a case screw fixing method. The case screw fixing method is a method of joining the cylindrical portion 60B and the cover body 70B by screwing a male threaded portion provided on one of the cylindrical portion 60B and the cover body 70B into a female threaded portion provided on the other of the cylindrical portion 60B and the cover body 70B. Note that the middle cover portion 3 shown in Figures 12 and 13 has the same configuration as the middle cover portion 3 shown in Figures 8 and 9, except for the fact that the cylindrical portion 60B and the cover body 70B are joined by a case screw fixing method, so the same reference numerals are used for common components and their explanation is omitted.

[0116] The cylindrical portion 71 of the cover body 70B protrudes forward to a position where it overlaps with the outer circumferential surface of the cylindrical portion 60B. On the inner circumferential surface of the cylindrical portion 71 of the cover body 70B, a female threaded portion 204 is provided at a position where it overlaps with the outer circumferential surface of the cylindrical portion 60B. On the other hand, the outer circumferential surface of the cylindrical portion 60B is provided with a male threaded portion 203 that engages with the female threaded portion 204.

[0117] In this inner cover section 3, when an assembly worker inserts the cylindrical section 60B into the inside of the cylindrical section 71 of the cover body 70B and rotates the cover body 70B relative to the cylindrical section 60B, the male threaded section 203 is screwed into the female threaded section 204, and the cover body 70B and the cylindrical section 60B are joined together.

[0118] When the inner cover portion 3 is assembled, the female thread portion 204 of the cover body 70B and the male thread portion 203 of the cylindrical portion 60B engage, thereby closing the gap between the cylindrical portion 71 of the cover body 70B and the outer surface of the cylindrical portion 60B. In addition, the gap between the rotating shaft 11 of the motor 10 and the cylindrical portion 73 of the cover body 70B is closed by the oil seal 101. Furthermore, the gap between the cylindrical portion 60B and the shaft holding member 49 is closed by the O-ring 104. Furthermore, the gap between the cylindrical portion 491 of the shaft holding member 49 and the output shaft 30 is closed by the O-ring 105. In this way, the gaps in the inner cover portion 3 are closed by the sealing portion 100, making it difficult for the lubricant filled in the inner cover portion 3 to leak out of the inner cover portion 3, and further suppressing the decrease in the lubricating effect of the lubricant. In this case, the sealing portion 100 is formed by the oil seal 101 and the O-rings 104 and 105 in the middle cover portion 3 shown in Figures 12 and 13.

[0119] Furthermore, the sealing portion 100 is not limited to being composed of an oil seal 101 and O-rings 104 and 105, and the number and type of sealing members constituting the sealing portion 100 can be changed as appropriate.

[0120] 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.

[0121] (3.3) Modification example 3 The hammer member 40 of the impact rotary tool 1 according to Modification 3 will be described with reference to Figure 14. The impact rotary tool 1 according to Modification 3 differs from the basic configuration in that the hammer member 40 is provided with a communication portion connecting the inner surface 411 and the outer surface 412 of the hammer member 40. Here, the inner surface 411 of the hammer member 40 is the wall surface of the insertion hole 41 provided in the hammer member 40, and the outer surface 412 of the hammer member 40 is the side surface of the cylindrically formed hammer member 40. Note that the impact rotary tool 1 according to Modification 3 has the same configuration as the basic configuration except for the provision of a communication portion on the hammer member 40, so the same reference numerals are used for components common to the basic configuration, and their explanations are omitted.

[0122] 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 rotation shaft 11, the striking portion 42 of the hammer member 40 housed in the middle cover 3 strikes the part to be struck 48 provided on the cylindrical portion 47. When the striking portion 42 of the hammer member 40 strikes the part to be struck 48, the hammer member 40 swings around the cam pin 80, causing the striking portion 42 to move over the part to be struck 48. However, if the inside of 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 40 may act as resistance when the hammer member 40 attempts to swing around the cam pin 80, potentially hindering the swing of the hammer member 40. If the swinging motion of the hammer member 40 around the cam pin 80 is inhibited, the striking portion 42 of the hammer member 40 may not be able to overcome the struck portion 48, potentially causing the impact mechanism 4, including the hammer member 40, to lock up.

[0123] Therefore, the hammer member 40 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 40 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 40 may be a groove 413 provided on the surface of the hammer member 40, or a through hole 414 that penetrates the hammer member 40.

[0124] For example, the hammer member 40 shown in Figure 14 is cylindrical with an insertion hole 41 provided along the axial direction of the output shaft 30, and two recessed grooves 413 and a through hole 414 are provided as communication parts at two points that intersect with the direction connecting the first groove 43 and the second groove 44.

[0125] The two grooves 413 extend along both sides of the hammer member 40 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 413 are provided from the inner surface 411 to the outer surface 412 of the cylindrical hammer member 40.

[0126] Furthermore, the through-hole 414 is provided so as to penetrate the hammer member 40 in a direction that intersects with the axial direction of the output shaft 30 and the direction that intersects with the direction connecting the first groove 43 and the second groove 44. One end of the through-hole 414 opens to the inner surface 411, and the other end of the through-hole 414 opens to the outer surface 412.

[0127] In the impact rotary tool 1 of the modified example 3, when the striking portion 42 of the hammer member 40 strikes the part to be struck 48 in accordance with the rotation of the middle cover portion 3, the hammer member 40 swings around the cam pin 80, allowing the lubricant present between the inner surface of the middle cover portion 3 and the hammer member 40 to flow (pass through) through the two grooves 413 and the through hole 414. Therefore, it is possible to avoid a situation where the lubricant present between the inner surface of the middle cover portion 3 and the hammer member 40 acts as a wall (resistance), making it difficult for the hammer member 40 to swing around the cam pin 80, thereby reducing the possibility of the impact mechanism 4 becoming locked.

[0128] The hammer member 40 shown in Figure 14 is provided with two grooves 413 and a through hole 414, but it is not essential to provide both grooves 413 and the through hole 414, and the number and shape of the connecting parts provided on the hammer member 40 can be changed as appropriate.

[0129] Furthermore, the hammer member 40 of the impact rotary tool 1 of Modification 1 or 2 may be provided with a communication portion (for example, a groove 413 and a through hole 414) as described in Modification 3, thereby reducing the possibility of the impact mechanism 4 locking up.

[0130] (3.4) Modification 4 The impact rotary tool 1 according to Modification 4 will be described with reference to Figure 15. 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.

[0131] In the impact rotary tool 1 of the modified example 4, a recess 66 is provided on the inner surface of the middle cover portion 3 near the cam pin 81 which is inserted into the first groove 43 of the hammer member 40.

[0132] In the impact rotary tool 1 of the modified example 4, when the striking portion 42 of the hammer member 40 strikes the part to be struck 48 in accordance with the rotation of the middle cover portion 3, the hammer member 40 swings around the cam pin 80, allowing the lubricant present between the inner surface of the middle cover portion 3 and the hammer member 40 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 40 acts as a wall (resistance), preventing the hammer member 40 from swinging easily around the cam pin 80, thus reducing the possibility of the impact mechanism 4 becoming locked.

[0133] 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.

[0134] (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.

[0135] The middle cover section 3 is composed of three members (cylindrical section 60, cover body 70, and shaft holding member 49), but the middle cover section 3 may be composed of two or more members combined together. Similarly, the middle cover section 3A is composed of two members (first cylindrical body 90 and second cylindrical body 95), but the middle cover section 3A may be composed of three or more members combined together.

[0136] (summary) Based on the embodiments described above, the following aspects are disclosed.

[0137] The impact rotary tool (1) in the first embodiment comprises a motor (10), an output shaft (30), impacted parts (48, 48A, 48B), a reduction mechanism (6), and an impact mechanism (4). The motor (10) rotates the rotation shaft (11). An end tool (T1) can be attached to the output shaft (30). The impacted parts (48, 48A, 48B) rotate together with the output shaft (30). The reduction mechanism (6) reduces the rotation of the rotation shaft (11) and transmits it to the output shaft (30). The impact mechanism (4) has hammer members (40, 40A, 40B) that rotate in accordance with the rotation of the rotation shaft (11) and strike the impacted parts (48, 48A, 48B). The impact mechanism (4) is positioned between the reduction mechanism (6) and the motor (10).

[0138] In this embodiment, the reduction mechanism (6) reduces the rotation of the motor (10)'s rotating shaft (11) and transmits it to the output shaft (30), so the part to be struck (48) also rotates at a speed reduced by the reduction mechanism (6). The hammer member (40) then rotates in accordance with the rotation of the rotating shaft (11), striking the part to be struck (48) and causing the output shaft (30) to rotate. Here, since the part to be struck (48) rotates at a speed reduced by the reduction mechanism (6), the impact force applied to the part to be struck (48) can be reduced compared to when the hammer member (40) strikes a stationary part to be struck (48), and an impact rotary tool (1) that can reduce impact noise can be provided.

[0139] In the second embodiment of the impact rotary tool (1), the impact mechanism (4) and the reduction mechanism (6) are arranged adjacent to each other, as in the first embodiment.

[0140] According to this embodiment, miniaturization can be achieved compared to the case where another component is interposed between the impact mechanism (4) and the reduction mechanism (6).

[0141] The impact rotary tool (1) of the third embodiment further comprises a main body case (2) and an inner cover section (3, 3A) in the first or second embodiment. The main body case (2) houses a motor (10), an output shaft (30), impacted parts (48, 48A, 48B), a reduction mechanism (6), and an impact mechanism (4). The inner cover section (3, 3A) is housed in the main body case (2) and covers the reduction mechanism (6) and the impact mechanism (4).

[0142] In this embodiment, the inner cover portion (3,3A) housed in the main body case (2) covers the reduction mechanism (6) and the impact mechanism (4), so the reduction mechanism (6) and the impact mechanism (4) can be double-covered by the inner cover portion (3,3A) and the main body case (2). Therefore, when a striking sound is generated when the hammer member (40,40A,40B) strikes the part to be struck (48,48A,48B), the impact sound transmitted to the outside of the main body case (2) can be reduced.

[0143] In the fourth embodiment of the impact rotary tool (1), the middle cover portion (3) rotates in conjunction with the rotation of the rotating shaft (11), as in the third embodiment.

[0144] 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.

[0145] In the fifth embodiment of the impact rotary tool (1), the middle cover (3A) is fixed to the main body case (2) as in the third embodiment.

[0146] According to this embodiment, the load on the motor (10) can be reduced compared to the case where the middle cover (3A) rotates in conjunction with the rotation of the motor's (10) rotating shaft (11).

[0147] In the sixth embodiment of the impact rotary tool (1), in any of the third to fifth embodiments, the middle cover portion (3,3A) is constructed by combining multiple members.

[0148] According to this embodiment, the work of housing the reduction mechanism (6) and the impact mechanism (4) inside the middle cover portion (3,3A) can be easily carried out.

[0149] The seventh embodiment of the impact rotary tool (1) further comprises a lubricant filled inside the middle cover portion (3,3A) in any of the third to sixth embodiments.

[0150] According to this embodiment, the inner cover portion (3,3A) covering the reduction mechanism (6) and the impact mechanism (4) suppresses the scattering of lubricant filled in the reduction mechanism (6) and the impact mechanism (4), thereby preventing a decrease in the lubricating effect of the lubricant. Therefore, deterioration of the components constituting the reduction mechanism (6) and the impact mechanism (4) can be suppressed.

[0151] The impact rotary tool (1) of the eighth embodiment further comprises a sealing portion (100) that seals the middle cover portion (3,3A) as in the seventh embodiment.

[0152] According to this embodiment, leakage of the lubricant filled in the inner cover portion (3,3A) to the outside of the inner cover portion (3,3A) can be further reduced, and the decrease in the lubricating effect of the lubricant can be further suppressed.

[0153] In the ninth embodiment of the impact rotary tool (1), in the seventh or eighth embodiment, the hammer members (40, 40A, 40B) are cylindrical in shape and have insertion holes (41) into which the striking parts (48, 48A, 48B) are inserted. The hammer members (40, 40A, 40B) are provided with connecting parts (413, 414) that connect the inner surface (411) and the outer surface (412) of the hammer members (40, 40A, 40B).

[0154] According to this embodiment, when the hammer members (40, 40A, 40B) strike the parts to be struck (32, 33), the lubricant present between the inner surface of the inner cover (3, 3A) and the hammer members (40, 40A, 40B) can move through the connecting parts (413, 414). Therefore, there is an advantage in that the possibility of the lubricant present between the inner surface of the inner cover (3, 3A) and the hammer members (40, 40A, 40B) hindering the movement of the hammer members (40, 40A, 40B) can be reduced.

[0155] In the impact rotary tool (1) of the tenth embodiment, in any of the seventh to ninth embodiments, the hammer members (40, 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) are respectively inserted. The width of the first groove (43) is greater than the diameter of the cam pins (80, 81). The hammer members (40, 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), 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).

[0156] According to this embodiment, when the hammer members (40, 40A, 40B) strike the parts to be struck (32, 33), the lubricant present between the inner surface of the inner cover (3, 3A) and the hammer members (40, 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 (3, 3A) and the hammer members (40, 40A, 40B) can act as resistance and potentially hinder the movement of the hammer members (40, 40A, 40B).

[0157] In the eleventh embodiment of the impact rotary tool (1), in any of the first to tenth embodiments, two impact targets (48A, 48B) are provided 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, 40B) corresponding to the two impact targets (48A, 48B). In accordance with the rotation of the motor (10), each of the two hammer members (40A, 40B) strikes the corresponding impact target (48A, 48B) of the two impact targets (48A, 48B).

[0158] According to this embodiment, the two hammer members (40A, 40B) strike the two striking parts (48A, 48B), thereby equally applying striking force to the two striking parts (48A, 48B) 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 (48A, 48B) of the output shaft (30), allowing the output shaft (30) to rotate smoothly.

[0159] The configurations relating to the second to eleventh aspects are not essential to the impact rotary tool (1) and can be omitted as appropriate. [Explanation of Symbols]

[0160] 1. Impact rotary tool 2. Main unit case 3,3A Middle cover section 4. Impact Mechanism 6 Reduction mechanism 10 motors 11 Rotation axis 30 Output shaft 40, 40A, 40B Hammer components 48,48A,48B Hit part 66 recesses 411 Inner surface 412 External surface 413 Concave groove (communication part) 414 Through hole (communication part) T1 tip tool

Claims

1. A motor that rotates the rotating shaft, An output shaft to which a cutting tool can be attached, The part that is struck rotates integrally with the output shaft, A reduction mechanism that reduces the rotation of the rotating shaft and transmits it to the output shaft, The impact mechanism includes a hammer member that rotates in accordance with the rotation of the rotating shaft and strikes the part to be struck, The impact mechanism is positioned between the reduction mechanism and the motor. Impact rotary tool.

2. The impact mechanism and the deceleration mechanism are arranged adjacent to each other. The impact rotary tool according to claim 1.

3. A main body case housing the motor, the output shaft, the part to be struck, the reduction mechanism, and the impact mechanism, The main body case further comprises an inner cover portion that is housed within the main body case and covers the deceleration mechanism and the impact mechanism, The impact rotary tool according to claim 1.

4. The aforementioned middle cover portion rotates in conjunction with the rotation of the rotation shaft. The impact rotary tool according to claim 3.

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

6. The aforementioned middle cover portion is composed of multiple members, The impact rotary tool according to claim 3.

7. The aforementioned middle cover portion is further equipped with a lubricant that is filled inside. The impact rotary tool according to claim 3.

8. The aforementioned middle cover portion is further provided with a sealing portion. The impact rotary tool according to claim 7.

9. The hammer member is cylindrical in shape and has an insertion hole into which the part to be struck 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 7.

10. 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 7.

11. Two of the impacted parts are provided at positions symmetrical to each other 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 10.

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