Working machine

Abstract

To provide a working machine equipped with a tool holding device capable of enhancing the degree of freedom of design of a guide sleeve.SOLUTION: In a tool holding device of a working machine, a hammer case 18 rotatably supporting an anvil 33 has a second regulation part 61. The second restriction part 61 is a cylindrical part at the front end of the hammer case 18, is coaxial with the shaft part 56 of the anvil 33, and is located behind the guide sleeve 40. The second restricting portion 61 is configured to restrict the maximum diameter of the setting ring 50 at the time of diameter expansion, that is, the outer diameter of the setting ring 50 when the diameter of the setting ring 50 is most expanded, so that the setting ring 50 does not expand to the extent of plastic deformation.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a work machine equipped with a tool holding device that holds a bit. [Background technology]

[0002] Patent Document 1 discloses a work machine equipped with a tool holding device for holding a bit, in which an elastic member made of an elastomer, a coil spring, or a metal set ring is provided on the outside of an engaging member that can engage with the bit, and the elastic member is supported by a guide sleeve. Patent Document 2 discloses a power tool equipped with a tool holding device for holding a bit, in which a band-shaped elastic member is provided on the outside of an engaging member that can engage with the bit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2024-42767 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-305664 Summary of the Invention [Problem to be solved by the invention]

[0004] The tool holding devices of Patent Documents 1 and 2 are configured such that the guide sleeve is always positioned radially outward of the elastic member, which makes it difficult to shorten the guide sleeve or simplify the shape of the guide sleeve, limiting the degree of freedom in designing the guide sleeve.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a work machine equipped with a tool holding device that allows for greater freedom in the design of guide sleeves. [Means for solving the problem]

[0006] One aspect of the present invention is A motor; a tool holding device rotated by the motor; A work machine having The tool holding device a tool holder extending in the front-to-rear direction, the tool holder having an insertion hole into which a bit can be inserted from the front to the rear, and an elongated hole that supports an engaging member engageable with the bit so that the engaging member can move between a front position and a rear position; a case portion that rotatably supports the tool holder; a substantially cylindrical operating member movable between a front position and a rear position on an outer periphery of the tool holder, the operating member having a first restricting portion positioned outward from the engaging member in a radial direction of the tool holder when the operating member is in the rear position and the engaging member is in the front position to restrict outward movement of the engaging member in the radial direction; a substantially annular elastic member located radially outward of the engaging member when the operating member is at a rear position and the engaging member is at the rear position, the elastic member elastically deforming when the engaging member at the rear position moves outward in the radial direction; a second restricting portion that is separate from the operating member and located behind the operating member, the second restricting portion being located outside the elastic member in the radial direction and configured to restrict the elastic member from expanding to an extent that causes plastic deformation; This is a work machine characterized by the above.

[0007] Another aspect of the present invention is a method for producing a semiconductor device comprising: A motor; a tool holding device rotated by the motor; A work machine having The tool holding device a tool holder having an insertion hole into which a bit can be inserted from the front to the rear, and an elongated hole that supports an engaging member that can engage with the bit so that the engaging member can move between a front position and a rear position; a case portion that rotatably supports the tool holder; a substantially cylindrical operating member movable between a front position and a rear position on an outer periphery of the tool holder, the operating member having a first restricting portion positioned outward from the engaging member in a radial direction of the tool holder when the operating member is in the rear position and the engaging member is in the front position to restrict outward movement of the engaging member in the radial direction; a substantially annular elastic member located radially outward of the engaging member when the operating member is at a rear position and the engaging member is at the rear position, the elastic member elastically deforming when the engaging member at the rear position moves outward in the radial direction; a restricting member that is separate from the operating member and located rearward of the operating member, and includes a second restricting portion that is located outside the elastic member in the radial direction, and is configured to be attachable to the case portion as a separate member; The work machine is characterized by having the following.

[0008] The present invention may be expressed as an "electric working machine" or "electric tool", and such expressions are also valid aspects of the present invention. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a work machine equipped with a tool holding device that allows for increased freedom in designing the guide sleeve. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side cross-sectional view of a work machine 1 according to a first embodiment. [Figure 2] 1A is a cross-sectional view of a main part of a tool holding device of a work machine 1. FIG. 1B is an exploded perspective view of the tool holding device. [Figure 3] FIG. 3 is a perspective view of the hammer case 18 and anvil 33 of FIG. 2(B) assembled together. [Figure 4] 10 is a side cross-sectional view showing a process of inserting and holding a bit 70 in a tool holding device. FIG. [Figure 5] FIG. 10 is a cross-sectional side view showing how the bit 70 is prevented from coming off the tool holding device. [Figure 6] 10 is a side cross-sectional view showing the process of removing the bit 70 from the tool holding device. FIG. [Figure 7] FIG. 6 is a cross-sectional view of a main part of a tool holding device of a work machine according to a second embodiment. [Figure 8] 8 is a perspective view of the hammer case 68, collar 62, and anvil 33 of FIG. 7 in an assembled state. [Figure 9] 10 is a perspective view showing a process of attaching a collar 93 (a restricting member) to a hammer case 90 in a tool holding device of a work machine according to a third embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Embodiment 1] (Overall composition) Fig. 1 is a side cross-sectional view of a work machine 1 according to embodiment 1. The work machine 1 is a cordless impact driver that operates on power from a battery pack 17. The front-rear and up-down directions of the work machine 1 are defined in Fig. 1.

[0012] The work machine 1 includes a housing 10, a tail cover 14, a trigger switch 15 as a first operating unit, a forward / reverse switch 16, a hammer case 18, an LED light 19 as a light, a motor 20, a reduction mechanism 28, a spindle 29, a hammer spring 31, a hammer 32, an anvil 33, a fan 34, a control board 35, a sensor / inverter board 36, a guide sleeve 40, and an operation panel unit 85.

[0013] The housing 10 is formed by, for example, two separate resin molded bodies, left and right, which are fixed together and integrated by screws, etc. The housing 10 includes a motor housing portion 11, a handle portion 12, and a battery pack mounting portion 13.

[0014] The motor housing 11 is a cylindrical portion whose central axis is approximately parallel to the front-to-rear direction. The upper end of the handle portion 12 is connected to the middle portion of the motor housing 11 in the front-to-rear direction and extends downward from that middle portion. The battery pack attachment portion 13 is provided at the lower end of the handle portion 12 and is adapted to detachably attach a battery pack 17. The tail cover 14 is, for example, a resin molded body. The tail cover 14 is connected and fixed to the rear end portion of the motor housing 11 by screws or the like and covers the rear opening of the motor housing 11.

[0015] The trigger switch 15 is supported at the front upper end of the handle portion 12. The trigger switch 15 is a motor drive operation unit (main operation unit) that the user uses to switch between driving and stopping the motor 40. The greater the amount of operation of the trigger switch 15, the higher the rotation speed of the motor 40.

[0016] The forward / reverse switch 16 is supported on the housing 10 near the upper side of the trigger switch 15. The forward / reverse switch 16 is a rotation direction switching operation unit that allows the user to switch between forward and reverse rotation of the motor 20. Forward rotation is rotation in the right direction (clockwise) when viewed from the rear. Reverse rotation is rotation in the left direction (counterclockwise) when viewed from the rear.

[0017] The hammer case 18 is made of a metal such as aluminum, is held in the motor housing 11, and extends forward from the motor housing 11. A plurality of lighting LEDs 19 are provided around the front end of the hammer case 18, for example, at equal angular intervals, and illuminate the working area of ​​the work machine 1.

[0018] The motor 20 is housed and held in the motor housing portion 11. The motor 20 is an inner rotor type brushless motor, and has a motor shaft 21 that is parallel to the front-to-rear direction. The speed reduction mechanism 28, the spindle 29, the hammer spring 31, the hammer 32, and the anvil 33 are housed and held in the hammer case 18.

[0019] The reduction mechanism 28 reduces the rotation speed of the motor 20 and transmits it to the spindle 29. The spindle 29 drives the hammer 32. The hammer spring 31 urges the hammer 32 forward. The hammer 32 is cam-engaged with the spindle 29 and is driven by the spindle 29 to rotate and strike the anvil 33. The hammer spring 31, hammer 32, and anvil 33 form a rotary striking mechanism and constitute the output part of the work machine 1. The motor 20, reduction mechanism 28, spindle 29, and rotary striking mechanism correspond to a working part that performs work using power.

[0020] The anvil 33 is rotatably supported on the hammer case 18 via a bearing 49. The anvil 33 has a bit insertion hole 37 that opens forward. The bit insertion hole 37 holds a tool bit such as a bit 70 shown in FIGS. 4 to 6. The guide sleeve 40 is a member that the user operates when removing the tool bit such as the bit 70 from the bit insertion hole 37. As will be described in detail later, the tool bit such as the bit 70 can be removed forward from the bit insertion hole 37 by pulling the guide sleeve 40 forward.

[0021] The fan 34 is provided inside the motor housing 11. The fan 34 is attached to the motor shaft 21 at the rear of the portion of the motor 20 excluding the motor shaft 21 (hereinafter referred to as the "motor main body"), rotates integrally with the motor shaft 21, and generates cooling air that cools the motor 20 and the like.

[0022] The control board 35 is provided inside the battery pack mounting portion 13. The control board 35 is equipped with a control unit (microcontroller) that controls the driving of the motor 20. The control board 35 is housed and held in a board case 80.

[0023] The sensor inverter board 36 is provided in front of the motor body inside the motor housing section 11. The sensor inverter board 36 is equipped with a magnetic sensor such as a Hall IC for detecting the rotational position of the motor 20, and a switching element for supplying a drive current to the motor 20.

[0024] The operation panel unit 85 faces the front upper surface of the battery pack mounting unit 13. The user can switch the drive mode (operation mode) and lighting mode of the work machine 1 using the operation panel unit 85. The operation panel unit 85 has functions as a drive mode selection operation unit, a drive mode display unit, and a lighting mode selection operation unit.

[0025] (Tool holding device) Fig. 2(A) is a cross-sectional view of a main part of the tool holding device of the work machine 1. Fig. 2(B) is an exploded perspective view of the tool holding device. Fig. 3 is a perspective view of the hammer case 18 and anvil 33 of Fig. 2(B) assembled together. The work machine 1 is characterized by the tool holding device that holds the bit 70 or other tool tip.

[0026] As shown in Figures 2(A) and (B), the tool holding device of the work machine 1 has a hammer case 18 as a case portion, an anvil 33 as a tool holder, a metal ball 39 as an engaging member, a guide sleeve 40 as an operating member, a guide spring 43 as a biasing member, a washer 44 as a spring receiving member, a retaining ring 45 as a retaining portion, and a set ring 50 as an elastic member.

[0027] The hammer case 18 rotatably supports the anvil 33. The hammer case 18 has a second restricting portion 61. The second restricting portion 61 is a cylindrical portion at the front end of the hammer case 18, is coaxial with the shaft portion 56 of the anvil 33, and is located behind the guide sleeve 40. Hereinafter, the radial direction of the shaft portion 56 will be referred to as the "radial direction," and the circumferential direction of the shaft portion 56 will be referred to as the "circumferential direction."

[0028] The second regulating portion 61 is configured to regulate the maximum diameter of the set ring 50 when expanded, i.e., the outer diameter of the set ring 50 when it is most expanded, and to regulate the set ring 50 so that it does not expand to the extent that it is plastically deformed.

[0029] The inner circumferential surface of the second restricting portion 61 is located radially inward of the outer circumferential surface of the guide sleeve 40. Therefore, the second restricting portion 61 restricts the set ring 50 from expanding beyond the outer diameter of the guide sleeve 40. In the example shown in FIG. 2(A) etc., the inner circumferential surface of the second restricting portion 61 is located radially inward of the inner circumferential surface of the guide sleeve 40. Therefore, the second restricting portion 61 restricts the set ring 50 from expanding beyond the internal space of the guide sleeve 40, i.e., the inner diameter of the accommodation portion that accommodates the guide spring 43. As another example, the inner circumferential surface of the second restricting portion 61 may be located radially between the outer circumferential surface and the inner circumferential surface of the guide sleeve 40.

[0030] The second restricting portion 61 is located radially outside the set ring 50 in both the state where the guide sleeve 40 is in the rear position as shown in Figure 2(A) and the state where the guide sleeve 40 is in the forward position as shown in Figures 6(B) and (C).

[0031] The anvil 33 is a metal body extending in the front-to-rear direction, and is configured so that a bit 70 can be inserted from front to rear into the bit insertion hole 37. As shown in FIG. 2(B), the anvil 33 has a shaft portion 56 and blade portions 57. The shaft portion 56 has the bit insertion hole 37 therein and is a cylindrical portion whose central axis is parallel to the front-to-rear direction. The blade portions 57 extend radially at the rear of the shaft portion 56. For example, three blade portions 57 are provided circumferentially at equal angular intervals. The blade portions 57 are struck by the hammer 32.

[0032] The anvil 33 has elongated holes 38 at the top and bottom of the side periphery of the bit insertion hole 37. The elongated holes 38 support (accommodate) metal balls 39 that can engage with grooves 72 (FIG. 4) of the bit 70 so that the metal balls 39 can move between a forward position and a rearward position. The grooves 72 have a cross-sectional shape that is curved, for example, in an arc shape, and go around the outer periphery of the bit 70.

[0033] The anvil 33 has a set ring mounting groove 59 (FIG. 2(B)) and an anvil protrusion 60 on its outer circumferential surface. The set ring mounting groove 59 overlaps the rear portion of the elongated hole 38 in the front-to-rear direction and runs around the outer periphery of the anvil 33, excluding the portion where the elongated hole 38 is located. The anvil protrusion 60 overlaps the middle portion of the elongated hole 38 in the front-to-rear direction and runs around the outer periphery of the anvil 33, excluding the portion where the elongated hole 38 is located. The anvil protrusion 60 forms the front wall of the set ring mounting groove 59. The elongated hole 38 extends forward of the anvil protrusion 60. The anvil protrusion 60 determines the rear position of the guide sleeve 40 (the position where it is most retracted). The front end of the anvil protrusion 60 is located forward of the front end of the second restricting portion 61 of the hammer case 18. Therefore, the second restricting portion 61 does not come into contact with the guide sleeve 40.

[0034] The set ring 50 is attached to a set ring attachment groove 59 shown in Figure 2(B). The set ring 50 is an elastic metal ring that has a notch 54 in a cylindrical ring portion 53 and can elastically expand or contract in diameter by changing the length of the notch 54. The ring portion 53 is positioned within the set ring attachment groove 59. The front-to-rear lengths of the ring portion 53 and the set ring attachment groove 59 are approximately equal to each other.

[0035] The set ring 50 has a protrusion 55 extending forward from the ring portion 53. The protrusions 55 are provided on the top and bottom of the set ring 50, respectively, and are located at the same radial positions as the elongated holes 38. The protrusions 55 extend to a position forward of the center of the anvil protrusion 60 and slightly rearward of the front end of the anvil protrusion 60 in the front-to-rear direction. The front end position of the protrusion 55 is approximately the same as the front end position of the second restriction portion 61 of the hammer case 18. The protrusions 55 restrict the metal balls 39 from moving radially outward. Circumferential movement of the set ring 50 is restricted by engagement between the protrusions 55 and the anvil protrusion 60.

[0036] As shown in Figures 4(C) and (D), when the guide sleeve 40 is in the rear position and the metal ball 39 is in the rear position, the set ring 50 is located outside the metal ball 39 in the radial direction of the anvil 33, and elastically deforms when the metal ball 39 in the rear position moves outward in the radial direction (Figure 4(C) → (D)).

[0037] When the metal ball 39 is positioned at the innermost radial position of the anvil 33 as shown in Figure 2(A), it protrudes a predetermined length from the opening of the long hole 38, which is the inner radial opening of the anvil 33, and extends partially inside the bit insertion hole 37.

[0038] The guide sleeve 40 is made of metal and is formed into a substantially cylindrical shape, and is attached to the anvil 33 so as to cover the outer periphery of the front end of the anvil 33. The guide sleeve 40 is movable between a forward position and a rearward position on the outer periphery of the anvil 33. The rear portion (rear end portion) of the guide sleeve 40 abuts (engages) with the front portion of the anvil protrusion 60, thereby determining the retracted position of the guide sleeve 40.

[0039] The guide sleeve 40 has a first restricting portion 42. The first restricting portion 42 is a convex portion (protrusion) that protrudes radially inward from the rear of the guide sleeve 40 and extends circumferentially. When the guide sleeve 40 is in the rear position and the metal ball 39 is in the forward position as shown in FIG. 2A, the first restricting portion 42 faces the elongated hole 38 in front of the second restricting portion 61 of the hammer case 18 and is located radially outward of the metal ball 39 to restrict radial outward movement of the metal ball 39. In the state shown in FIG. 2A, the center of gravity of the metal ball 39 and the range of the first restricting portion 42 overlap in the front-to-rear direction. When the guide sleeve 40 is in the forward position as shown in FIGS. 6B and 6C, most of the first restricting portion 42 is located forward of the elongated hole 38, allowing radial outward movement of the metal ball 39.

[0040] The guide spring 43 is a compression coil spring whose central axis is parallel to the central axis of the anvil 33, i.e., the front-to-rear direction. The guide spring 43 urges the guide sleeve 40 rearward relative to the anvil 33, i.e., urges the guide sleeve 40 toward a rearward position. The guide spring 43 is disposed between the inner peripheral surface of the guide sleeve 40 and the outer peripheral surface of the anvil 33. The rear end of the guide spring 43 is supported by a first restricting portion 42 of the guide sleeve 40. The front end of the guide spring 43 is supported by a washer 44 provided at the front end of the anvil 33. The guide spring 43 is compressed in the front-to-rear direction by the first restricting portion 42 and the washer 44. The forward movement of the washer 44 relative to the anvil 33 is restricted by a retaining ring 45 located in front of the guide spring 43 and provided at the front end of the anvil 33. This prevents the guide spring 43 and washer 44 from falling forward from the anvil 33.

[0041] 4(A) to 4(F) show the process of inserting and holding the bit 70 in the tool holding device.

[0042] As the bit 70 is inserted into the bit insertion hole 37, the metal ball 39 is pushed by the inclined portion (tapered portion) at the rear end of the bit 70, and moves toward the rear of the elongated hole 38 as shown in Figures 4(A) to (D), and also moves outward in the radial direction of the anvil 33 while elastically deforming the set ring 50 as shown in Figures 4(B) to (D), and assumes a positional relationship that does not prevent further insertion of the bit 70 as shown in Figure 4(D).

[0043] 4(E) and 4(F), as the bit 70 is further inserted, the groove 72 of the bit 70 comes to a position where it overlaps with the elongated hole 38 in the front-to-rear direction, and the groove 72 and the elongated hole 38 face each other. The metal ball 39 receives a repulsive force from the set ring 50 and moves inward in the radial direction of the anvil 33 along the surface shape of the groove 72.

[0044] In the state shown in FIG. 4(F), the metal ball 39 engages with the groove 72 of the bit 70 and the first restricting portion 42 of the guide sleeve 40, locking the bit 70. If an attempt is made to pull the bit 70 forward from the state shown in FIG. 4(F), the metal ball 39 will attempt to move outward in the radial direction of the anvil 33 along the surface shape of the groove 72, but as shown in FIGS. 5(A) and (B), its outward movement is restricted by the first restricting portion 42. Therefore, the metal ball 39 is caught in the groove 72 of the bit 70. Therefore, the bit 70 cannot be pulled out forward from the state shown in FIG. 5(B) unless the guide sleeve 40 is operated.

[0045] 6(A) to 6(C) show the process of removing the bit 70 from the tool holding device.

[0046] When removing the bit 70, first pull the guide sleeve 40 forward to move it to a forward position against the bias of the guide spring 43. Then, as shown in FIG. 6(A), the first restricting portion 42 of the guide sleeve 40 moves forward of the metal ball 39, and a gap is formed between the first restricting portion 42 of the guide sleeve 40 and the front portion of the set ring 50 (the front end of the protrusion 55 shown in FIG. 2(B)) radially outside the metal ball 39. When the bit 70 is pulled forward in this state, the metal ball 39 moves radially outward along the surface shape of the groove 72, and as shown in FIG. 6(B), it assumes a position that does not prevent further removal of the bit 70. By further pulling the bit 70 forward, the bit 70 can be removed from the bit insertion hole 37 as shown in FIG. 6(C). When the guide sleeve 40 is in the forward position (the most advanced position), the length of the gap between the first restricting portion 42 of the guide sleeve 40 and the front portion of the set ring 50 (the front end portion of the protrusion 55 shown in Figure 2 (B)) is configured to be equal to or less than the diameter of the metal ball 39, thereby preventing the metal ball 39 from falling off.

[0047] This embodiment has the following advantages.

[0048] (1) The second restricting portion 61 of the hammer case 18 is located radially outward of the set ring 50 and restricts the set ring 50 from expanding to such an extent that it would be plastically deformed. Therefore, there is no need to provide the guide sleeve 40 with a restricting portion that restricts the expansion of the set ring 50. Therefore, compared to when the guide sleeve 40 is provided with a restricting portion that restricts the expansion of the set ring 50, the front-to-rear length of the guide sleeve 40 can be shortened and the shape of the guide sleeve 40 can be simplified. This increases the degree of freedom in designing the guide sleeve 40.

[0049] (2) The second restricting portion 61 of the hammer case 18 is located radially outside the set ring 50 and restricts excessive expansion of the set ring 50 in both states, that is, when the guide sleeve 40 is in the rear position as shown in FIG. 2(A) and when the guide sleeve 40 is in the forward position as shown in FIGS. 6(B) and 6(C). Therefore, plastic deformation of the set ring 50 can be effectively suppressed regardless of the position of the guide sleeve 40. In this regard, in a configuration in which a restricting portion that restricts the expansion of the set ring 50 is provided on the guide sleeve 40, there is a concern that, due to vibrations during operation or the like, the guide sleeve 40 may move forward excessively and the expansion of the set ring 50 may no longer be restricted (the set ring 50 may no longer be supported from the radial outside). In this state, the metal balls 39 may collide with the set ring 50, causing plastic deformation or damage to the set ring 50. If the set ring 50 is plastically deformed or damaged, the force holding the metal balls 39 radially inward weakens, causing the bit 70 to come out unexpectedly or worsening the feeling when inserting the bit 70. This embodiment is intended to solve these problems in an optimal manner.

[0050] (3) Since the second restricting portion 61 is configured integrally with the hammer case 18, the number of parts of the tool holding device is reduced compared to when the second restricting portion 61 is separate from the hammer case 18.

[0051] [Embodiment 2] 7 is a cross-sectional view of a main part of a tool holding device for a work machine according to embodiment 2. The following description will focus on the differences from embodiment 1.

[0052] The tool holding device of this embodiment is configured by replacing the hammer case 18 of the tool holding device of embodiment 1 with a hammer case 68 that does not have a second regulating portion 61, and attaching a collar 62 as a regulating member having a second regulating portion 63 to the front of the hammer case 68.

[0053] The collar 62 can be attached to the hammer case 68 by, for example, press fitting. Figure 8 shows the state in which the collar 62 is attached to the hammer case 68 by press fitting and combined with the anvil 33.

[0054] The second restricting portion 63 is a cylindrical portion at the front end of the collar 62, is coaxial with the anvil 33, and is located behind the guide sleeve 40. The second restricting portion 63 acts on the set ring 50 in the same manner as the second restricting portion 61 of the hammer case 18 of the first embodiment.

[0055] The collar 62 can be made of a different material from the hammer case 68. Therefore, by making the collar 62 out of, for example, resin, the tool holding device can be made lighter and the heat of the hammer case 68 can be made less likely to be transmitted to the worker.

[0056] [Embodiment 3] 9(A) to 9(C) show the process of attaching a collar 93 as a restricting member to a hammer case 90 in a tool holding device for a work machine according to embodiment 3. The following description will focus on the differences from embodiment 2.

[0057] In this embodiment, the hammer case 68 of the second embodiment is replaced with a hammer case 90, and the collar 62 is replaced with a collar 93. As shown in FIG. 9(A), the hammer case 90 has a pair of anti-rotation protrusions 91 on the outer periphery of the tip. As shown in FIG. 9(B), the collar 93 has a recess that fits into the anti-rotation protrusions 91. A groove 92 extending in the circumferential direction is provided on the outer periphery of the anti-rotation protrusions 91, and a groove 95 extending in the circumferential direction is provided on the outer periphery of the collar 93, with the grooves 92 and 95 continuing around the entire circumference. As shown in FIG. 9(C), the collar 93 is attached to and fixed to the hammer case 90 by a retaining ring 96 (C-type retaining ring). A second restricting portion 94 of the collar 93 acts on the set ring 50 in the same manner as the second restricting portion 61 of the hammer case 18 of the first embodiment.

[0058] Although the present invention has been described above using the embodiments as examples, the present invention is not limited to the embodiments. Various modifications can be made to the details specifically described in the embodiments within the scope of the claims.

[0059] The second restricting portion is not limited to being provided on the hammer case or the collar, but may be a portion of the bearing 49 shown in FIG.

[0060] The guide sleeve 40 may be a resin molded body. In this case, portions of the guide sleeve 40 that are susceptible to wear due to engagement with the metal balls 39, such as the first restriction portion 42, may be made of metal by composite molding. The position of the elongated hole 38 may be changed to the left or right side of the periphery of the bit insertion hole 37. The number of elongated holes 38 and metal balls 39 may be one.

[0061] The elastic member is not limited to the set ring 50, but may be, for example, a ring-shaped or cylindrical elastomer, one or more O-rings, a coil spring that wraps around the anvil 33, or the like.

[0062] The present invention is not limited to impact drivers, but can be applied to any work machine that holds a tip tool such as a bit. The present invention is not limited to cordless work machines, but may also be a corded work machine that operates on power supplied from an external AC power source via a power cord. [Explanation of symbols]

[0063] 1...Work machine, 10...Housing, 11...Motor accommodating section, 12...Handle section, 13...Battery pack mounting section, 14...Tail cover, 15...Trigger switch, 16...Forward / reverse switch, 17...Battery pack, 18...Hammer case, 19...LED lighting, 20...Motor, 21...Motor shaft, 28...Reduction mechanism, 29...Spindle, 31...Hammer spring, 32...Hammer, 33...Anvil (tool holder), 34...Fan, 35...Control board, 36...Sensor / inverter board, 37...Bit insertion hole, 38...Elongated hole, 39...Metal ball (engagement member), 40...Guide sleeve, 42...First restriction section (convex section), 43 ...Guide spring (biasing member), 44...Washer (spring support member), 45...Retaining ring, 49...Bearing, 50...Set ring (elastic member), 53...Ring portion, 54...Notch, 55...Convex portion, 56...Shaft portion, 57...Blade portion, 59...Set ring mounting groove, 60...Anvil protrusion portion, 61...Second restricting portion, 62...Collar (restricting member), 63...Second restricting portion, 68...Hammer case, 70...Bit (tip tool), 72...Groove portion, 80...Circuit board case, 85...Operation panel portion, 90...Hammer case, 91...Anti-rotation convex portion, 92...Groove portion, 93...Collar (restricting member), 94...Second restricting portion, 95...Groove portion, 96...Retaining ring.

Claims

1. A motor; a tool holding device rotated by the motor; A work machine having The tool holding device a tool holder extending in the front-to-rear direction, the tool holder having an insertion hole into which a bit can be inserted from the front to the rear, and an elongated hole that supports an engaging member engageable with the bit so that the engaging member can move between a front position and a rear position; a case portion that rotatably supports the tool holder; a substantially cylindrical operating member movable between a front position and a rear position on an outer periphery of the tool holder, the operating member having a first restricting portion positioned outward from the engaging member in a radial direction of the tool holder when the operating member is in the rear position and the engaging member is in the front position to restrict outward movement of the engaging member in the radial direction; a substantially annular elastic member located radially outward of the engaging member when the operating member is at a rear position and the engaging member is at the rear position, the elastic member elastically deforming when the engaging member at the rear position moves outward in the radial direction; a second restricting portion that is separate from the operating member and located behind the operating member, the second restricting portion being located outside the elastic member in the radial direction and configured to restrict the elastic member from expanding to an extent that would cause plastic deformation; A work machine characterized by:

2. A motor; a tool holding device rotated by the motor; A work machine having The tool holding device a tool holder having an insertion hole into which a bit can be inserted from the front to the rear, and an elongated hole that supports an engaging member that can engage with the bit so that the engaging member can move between a front position and a rear position; a case portion that rotatably supports the tool holder; a substantially cylindrical operating member movable between a front position and a rear position on an outer periphery of the tool holder, the operating member having a first restricting portion positioned outward from the engaging member in a radial direction of the tool holder when the operating member is in the rear position and the engaging member is in the front position to restrict outward movement of the engaging member in the radial direction; a substantially annular elastic member located radially outward of the engaging member when the operating member is at a rear position and the engaging member is at the rear position, the elastic member elastically deforming when the engaging member at the rear position moves outward in the radial direction; a restricting member that is separate from the operating member and is located rearward of the operating member and includes a second restricting portion that is located outward of the elastic member in the radial direction, and is configured to be attachable to the case portion as a separate member; A work machine characterized by having:

3. The work machine according to claim 1 or 2, The second restricting portion is configured to restrict the elastic member from expanding beyond the outer diameter of the operating member. A work machine characterized by:

4. The work machine according to claim 1 or 2, The second restricting portion is configured to restrict the elastic member from expanding beyond an inner diameter of an accommodating portion that accommodates a guide spring of the operating member. A work machine characterized by:

5. The work machine according to claim 1, The second restricting portion is integrally formed with the case portion. A work machine characterized by:

6. The work machine according to claim 1, The second restricting portion is configured to be attachable to the case portion as a separate body. A work machine characterized by:

7. The work machine according to claim 2 or 6, The second restricting portion is made of a material different from that of the case portion. A work machine characterized by:

8. The work machine according to claim 1, the second restricting portion is located outside the elastic member in the radial direction when the operating member is located at either the front position or the rear position. A work machine characterized by:

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