Work machine

Abstract

Provided is a work machine comprising a compact tool-holding device. An anvil 33 has, at a location between an annular part 53 of a set ring 50 and a protruding part 42 of a guide sleeve 40 in the front-back direction, an anvil protrusion 60 for restricting backward movement of the guide sleeve 40. The anvil protrusion 60 protrudes radially outward from the outer circumference of the anvil 33 at a location between the back-end part of a long hole 38 and the front-end part of the long hole 38 in the front-back direction. The set ring 50 has a projection 55 extending forward from the annular part 53 at a position overlapping the long hole 38 in the circumferential direction. The anvil protrusion 60 is provided at a position overlapping the projection 55 in the front-back direction.

Description

Work equipment

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

[0002] Patent Document 1 discloses a work machine equipped with a tool holding device that can mount a bit without manipulating a tool sleeve. This tool holding device has a rear stopper ring provided on the outer periphery of the tool holder, rearward of the elongated hole that holds the ball that engages with the bit. When the tool sleeve is biased rearward relative to the tool holder, the rear stopper ring restricts the rearward sliding limit position.

[0003] Japanese Patent Application Laid-Open No. 2000-218412

[0004] The present inventors have recognized the following problems in a work machine equipped with a tool holding device that holds a bit: Problem 1: To provide a work machine equipped with a compact tool holding device. Problem 2: To provide a work machine equipped with a highly durable tool holding device. Problem 3: To provide a work machine equipped with a highly reliable tool holding device.

[0005] One aspect of the present invention is a work machine having a motor and a tool holding device rotated by the motor, wherein the tool holding device is a tool holder extending in a 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 that can engage with the bit so that the engaging member can be moved between a front position and a rear position, and a substantially cylindrical operating member that is movable between a front position and a rear position on the outer periphery of the tool holder, and when the operating member is in the rear position and the engaging member is in the front position, the operating member is located outside the engaging member in the radial direction of the tool holder and supports the engaging member. a first elastic member having a substantially annular shape and positioned radially outward from the engaging member when the operating member is in a rear position and the engaging member is in the rear position, the first elastic member elastically deforming when the engaging member in the rear position moves radially outward, wherein the first elastic member has an annular portion extending substantially annularly on the outer periphery of the tool holder, and the tool holder has a second restricting portion positioned between the annular portion and the first restricting portion in the front-to-rear direction and restricting rearward movement of the operating member.

[0006] Another aspect of the present invention is a work machine having a motor and a tool holding device rotated by the motor, wherein the tool holding device is a tool holder extending in a 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; and a substantially cylindrical operating member that is movable between a front position and a rear position on the outer periphery of the tool holder, the operating member having a first restricting portion that is located outside the engaging member in a radial direction of the tool holder and restricts outward movement of the engaging member in the radial direction when the operating member is in the rear position and the engaging member is in the forward position. and a substantially annular first elastic member located radially outward of the engaging member when the operating member is in a rear position and the engaging member is in the rear position, the first elastic member elastically deforming when the engaging member at the rear position moves radially outward, wherein the first elastic member has an annular portion extending substantially annularly on the outer periphery of the tool holder, and one or more protrusions protruding from the annular portion, and the tool holder has a third restricting portion that contacts one and the other circumferential sides of the one or more protrusions of the first elastic member to suppress rattling of the first elastic member in the circumferential direction.

[0007] Another aspect of the present invention is a work machine having a motor and a tool holding device rotated by the motor, wherein the tool holding device is a tool holder extending in a 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 be moved between a front position and a rear position, and a substantially cylindrical operating member that is movable between a front position and a rear position on the outer periphery of the tool holder, wherein when the operating member is in the rear position and the engaging member is in the front position, the operating member is located outside the engaging member in the radial direction of the tool holder and supports the engaging member in the radial direction. a first elastic member having a generally annular shape and positioned outside the engaging member in the radial direction when the operating member is in the rear position and the engaging member is in the rear position, the first elastic member elastically deforming when the engaging member in the rear position moves outward in the radial direction; and a second elastic member provided separately from the first elastic member and positioned behind the engaging member in the front-to-rear direction when the engaging member in the forward position moves rearward.

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

[0009] According to the present invention, at least one of the above problems 1 to 3 can be solved.

[0010] 14 is a side cross-sectional view of a working machine 1 according to a first embodiment. An exploded perspective view of a tool holding device of the working machine 1. A side cross-sectional view of the tool holding device. A side cross-sectional view showing a process of inserting and holding a bit 70 in the tool holding device. A side cross-sectional view showing that removal of the bit 70 from the tool holding device is restricted. A side cross-sectional view showing a process of removing the bit 70 from the tool holding device. A cross-sectional view taken along the line A-A in FIG. 3. A front cross-sectional view of a tool holding device of a working machine according to a second embodiment. A front cross-sectional view of a tool holding device of a working machine according to a third embodiment. A perspective view of a separated state of anvil 33B and set ring 50B in the third embodiment. A perspective view of an assembled state of anvil 33B and set ring 50B. An exploded perspective view of a tool holding device of a working machine according to a fourth embodiment. A perspective view of a state in which a spring 100 is assembled to anvil 33C in the fourth embodiment. A perspective view of a state in which a set ring 50 is assembled from the state of FIG. 13. A perspective view of a state in which a guide spring 43, a washer 44, and a retaining ring 45 are assembled from the state of FIG. 14. 15 is a perspective view also showing the guide sleeve 40. A side cross-sectional side view of a tool holding device of embodiment 4. A side cross-sectional side view of a state in which a bit 70 is being inserted into the tool holding device of FIG. 17. (A) is a perspective view of a spring 100A that can be used in place of the spring 100. (B) is a side view of the spring 100A. A perspective view of a flat spring 110 used in a tool holding device of a work machine according to embodiment 5. A side cross-sectional side view of a tool holding device of embodiment 5. A side cross-sectional side view of a state in which a bit 70 is being inserted into the tool holding device of FIG. 21. A perspective view of a spring 150 that can be used in place of the set ring 50.

[0011] [Embodiment 1] (Overall Configuration) 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. Fig. 1 defines the front-rear and up-down directions of the work machine 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, one for the left and one for the 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 handle portion 12 has an upper end connected to a 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 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 clockwise rotation when viewed from the rear. Reverse rotation is counterclockwise rotation when viewed from the rear.

[0017] The hammer case 18 is made of 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 a hammer 32. A 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 rotary-strike an anvil 33. The hammer spring 31, hammer 32, and anvil 33 form a rotary-striking mechanism and constitute the output section of the work machine 1. The motor 20, reduction mechanism 28, spindle 29, and rotary-striking mechanism correspond to a working section 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 tip such as the bit 70 shown in FIGS. 4 to 6. The guide sleeve 40 is a member that the user operates when removing the tool tip such as the bit 70 from the bit insertion hole 37. As will be described in detail later, the tool tip 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 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 portion 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 portion 13. The user can use the operation panel unit 85 to switch the drive mode (operation mode) and lighting mode of the work machine 1. The operation panel unit 85 functions as a drive mode selection operation unit, a drive mode display unit, and a lighting mode selection operation unit.

[0025] (Configuration of Tool Holding Device) Fig. 2 is an exploded perspective view of the tool holding device of the work machine 1. Fig. 3 is a side cross-sectional view of the tool holding device. The work machine 1 is characterized by the structure of the tool holding device that holds the tool bit 70 or other tool tip.

[0026] As shown in Figures 2 and 3, the tool holding device of the work machine 1 has 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 a first elastic member.

[0027] The anvil 33 is a metal body extending in the front-rear direction, and is configured so that the bit 70 can be inserted from the front to the rear into the bit insertion hole 37. The anvil 33 is rotatably supported on the hammer case 18 by a bearing 49, as shown in FIG.

[0028] As shown in FIG. 2 , the anvil 33 has a shaft portion 56 and blade portions 57. The shaft portion 56 has a bit insertion hole 37 therein and is a cylindrical portion with a central axis parallel to the front-to-rear direction. 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." The shaft portion 56 has a large diameter portion 56a and a small diameter portion 56b. The large diameter portion 56a is connected to the rear of the small diameter portion 56b. The blade portions 57 extend radially at the rear of the shaft portion 56. For example, three blade portions 57 are provided at equal angular intervals in the circumferential direction. The blade portions 57 are struck by the hammer 32.

[0029] The anvil 33 has elongated holes 38 at the top and bottom of the side periphery of the bit insertion hole 37 in the small-diameter portion 56b. 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 extend around the outer periphery of the bit 70.

[0030] The anvil 33 has a set ring attachment groove 59 (FIG. 2) and an anvil protrusion 60 serving as a second restricting portion on the outer circumferential surface of the rear portion of the small diameter portion 56b.

[0031] The set ring attachment groove 59 extends around the outer periphery of the anvil 33 excluding the portion where the elongated hole 38 is present, at a position overlapping the rear portion of the elongated hole 38 in the front-rear direction. The set ring attachment groove 59 is adjacent to the rear of the anvil protrusion 60.

[0032] The anvil protrusion 60 is located between the annular portion 53 of the set ring 50 and the protrusion 42 of the guide sleeve 40 in the front-rear direction. The anvil protrusion 60 extends radially outward from the outer periphery of the anvil 33 at a position overlapping the middle portion of the elongated hole 38 in the front-rear direction, i.e., between the rear end and front end of the elongated hole 38 in the front-rear direction, and goes around the outer periphery of the anvil 33 excluding the portion where the elongated hole 38 is present.

[0033] The anvil protrusion 60 forms the front wall of the set ring attachment groove 59. The elongated hole 38 extends forward of the anvil protrusion 60. The anvil protrusion 60 restricts rearward movement of the guide sleeve 40 by abutting its front surface, abutment surface 65 (shown in the enlarged portion of FIG. 2 ), against the rear portion of the convex portion 42 of the guide sleeve 40, and determines the rear position of the guide sleeve 40 (the position in which it is most retracted).

[0034] As shown in the enlarged portion of Figure 2, the anvil protrusion 60 has anti-rotation surfaces 64. The anti-rotation surfaces 64 are end faces of the anvil protrusion 60 in the circumferential direction, and are located on both sides of the elongated hole 38. The protrusion 55 of the set ring 50 is located between the opposing anti-rotation surfaces 64. The engagement between the anti-rotation surfaces 64 and the protrusion 55 regulates the circumferential position of the set ring 50.

[0035] The set ring 50 is attached to a set ring attachment groove 59 shown in Figure 2. The set ring 50 is an elastic metal ring having a notch 54 in a cylindrical annular portion 53, and the diameter can be elastically expanded or contracted by changing the length of the notch 54. The annular portion 53 is positioned within the set ring attachment groove 59. The front-to-rear lengths of the annular portion 53 and the set ring attachment groove 59 are approximately equal to each other.

[0036] The set ring 50 has protrusions 55 that protrude forward from the annular portion 53 at positions that overlap the elongated holes 38 in the circumferential direction. The protrusions 55 are provided on the upper and lower parts of the set ring 50. The protrusions 55 are provided at positions that overlap the anvil protrusions 60 in the front-to-rear direction. Specifically, the protrusions 55 extend to a position that is forward of the center of the anvil protrusions 60 and slightly rearward of the front end of the anvil protrusions 60. The protrusions 55 restrict the metal balls 39 from moving radially outward. Engagement between the protrusions 55 and the anvil protrusions 60 in the circumferential direction restricts movement of the set ring 50 in the circumferential direction.

[0037] 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 radially outward of the metal ball 39, and elastically deforms when the metal ball 39 in the rear position moves radially outward (Figure 4(C) → (D)).

[0038] When the metal ball 39 is positioned at the innermost radial position as shown in Figure 3, it protrudes a predetermined length from the inner radial opening of the elongated hole 38 and extends partially inside the bit insertion hole 37.

[0039] 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 retracted position of the guide sleeve 40 is determined by the rear portion of the convex portion 42 of the guide sleeve 40 abutting (engaging) with the front surface of the anvil protrusion 60 (the abutment surface 65 shown in the enlarged portion of Figure 2).

[0040] The guide sleeve 40 has a recess 41 and a protrusion 42 serving as a first restricting portion.

[0041] The recess 41 is a recessed portion relative to the protrusion 42 and extends circumferentially around the rear inner peripheral surface of the guide sleeve 40. The recess 41 forms a space that allows the set ring 50 to expand in diameter. The recess 41 faces the rear portion of the elongated hole 38 when the guide sleeve 40 is in the rear position as shown in FIG. 3. The recess 41 faces the front portion of the elongated hole 38 when the guide sleeve 40 is in the forward position as shown in FIGS. 6(B) and 6(C).

[0042] The protrusion 42 is a protrusion that protrudes radially inward from the front side of the recess 41 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. 3, the protrusion 42 faces the elongated hole 38 and is located radially outward of the metal ball 39, restricting radial outward movement of the metal ball 39. In the state shown in FIG. 3, the center of gravity of the metal ball 39 and the extent of the protrusion 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 protrusion 42 is located forward of the elongated hole 38, allowing radial outward movement of the metal ball 39.

[0043] 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 protrusion 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 protrusion 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.

[0044] 4A to 4F show the process of inserting and holding the bit 70 in the tool holding device.

[0045] 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 FIGS. 4(A) to 4(D). At the same time, the metal ball 39 moves radially outward while elastically deforming the set ring 50 as shown in FIGS. 4(B) to 4(D), and assumes a positional relationship that does not prevent further insertion of the bit 70 as shown in FIG. 4(D).

[0046] 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 faces the elongated hole 38. The metal ball 39 is subjected to the repulsive force of the set ring 50 and moves radially inward along the surface shape of the groove 72.

[0047] In the state shown in FIG. 4(F), the metal ball 39 engages with the groove 72 of the bit 70 and the protrusion 42 of the guide sleeve 40, locking the bit 70. When an attempt is made to withdraw the bit 70 from the state shown in FIG. 4(F), the metal ball 39 attempts to move radially outward along the surface shape of the groove 72. However, as shown in FIGS. 5(A) and 5(B), this outward movement is restricted by the protrusion 42. Therefore, the metal ball 39 is caught in the groove 72 of the bit 70. Therefore, the bit 70 cannot be withdrawn forward from the state shown in FIG. 5(B) unless the guide sleeve 40 is operated. When an attempt is made to withdraw the bit 70 from the state shown in FIG. 4(F), the protrusion 55 of the set ring 50 functions as a guide for the metal ball 39 as it moves forward as shown in FIGS. 5(A) and 5(B), ensuring that the metal ball 39 is positioned radially inside the protrusion 42.

[0048] 6A-6C show the process of removing the bit 70 from the tool holding device.

[0049] To remove the bit 70, first pull the guide sleeve 40 forward, moving it to a forward position against the bias of the guide spring 43. Then, as shown in FIG. 6(A), the convex portion 42 of the guide sleeve 40 moves forward of the metal ball 39, and the concave portion 41 of the guide sleeve 40 is positioned radially outward of the metal ball 39. Pulling the bit 70 forward in this state moves the metal ball 39 radially outward along the surface shape of the groove 72, and assumes a position that does not prevent further removal of the bit 70, as shown in FIG. 6(B). Pulling the bit 70 forward further removes the bit 70 from the bit insertion hole 37, as shown in FIG. 6(C).

[0050] Figure 7 is a cross-sectional view taken along line A-A in Figure 3. The inner peripheral surface of the annular portion 53 of the set ring 50 contacts the outer peripheral surface of the anvil 33 (the bottom surface of the set ring mounting groove 59) over the entire circumference. In the circumferential direction, there is a gap between the protruding portion 55 of the set ring 50 and the anti-rotation surfaces 64 of the anvil protrusions 60 located on both sides of the protruding portion 55.

[0051] This embodiment has the following advantages.

[0052] (1) The anvil 33 has an anvil protrusion 60 that restricts rearward movement of the guide sleeve 40 between the annular portion 53 of the set ring 50 and the protrusion 42 of the guide sleeve 40 in the front-to-rear direction. Therefore, compared to a configuration in which a stopper ring or a protrusion is provided on the outer periphery of the anvil 33 rearward of the set ring 50 or the elongated hole 38 to restrict rearward movement of the guide sleeve 40, the anvil 33 can be made shorter, and the tool holding device can be made more compact.

[0053] (2) The anvil protrusion 60 protrudes radially outward from the outer periphery of the anvil 33 between the rear end of the elongated hole 38 and the front end of the elongated hole 38 in the front-rear direction. Therefore, the portion of the outer periphery of the anvil 33 that overlaps with the elongated hole 38 in the front-rear direction can be effectively utilized to restrict rearward movement of the guide sleeve 40, and an increase in the size of the anvil 33 due to the restriction by the guide sleeve 40 can be suppressed.

[0054] (3) The set ring 50 has a protrusion 55 extending forward from the annular portion 53 at a position that circumferentially overlaps the elongated hole 38. Therefore, compared to a case where the protrusion 55 is not present, the annular portion 53 and the protrusion 55 can cover a wider area of ​​the elongated hole 38, increasing the reliability of engagement with the metal balls 39. This improves the reliability of the tool holding device.

[0055] (4) The anvil protrusion 60 is positioned so as to overlap the protrusion 55 in the front-rear direction. Therefore, the protrusion 55 can cover the area of ​​the elongated hole 38 that cannot be covered by the annular portion 53 alone, thereby increasing the reliability of engagement with the metal ball 39. This improves the reliability of the tool holding device.

[0056] (5) When an attempt is made to pull out the bit 70 without operating the guide sleeve 40, the protrusion 55 guides the metal ball 39 toward the radially inward direction of the convex portion 42. This prevents the bit 70 from coming out simply by pulling the bit 70 without operating the guide sleeve 40, thereby improving the reliability of the tool holding device.

[0057] [Embodiment 2] Figure 8 is a front cross-sectional view of a tool holding device for a work machine according to embodiment 2. The cut position of the cross section in Figure 8 is the same as the cut position of the cross section in Figure 7. The following description will focus on differences from embodiment 1.

[0058] In the tool holding device of this embodiment, the anvil 33 and the set ring 50 of the tool holding device of the first embodiment are replaced with an anvil 33A and a set ring 50A, respectively.

[0059] The circumferential position of the protrusion 55A of the set ring 50A is closer to the notch 54 than the circumferential position of the protrusion 55 of the set ring 50. The anvil 33A has the anvil protrusion 60 of the anvil 33 replaced with an anvil protrusion 60A. The anti-rotation surface 64A of the anvil protrusion 60A is formed by inclining the anti-rotation surface 64 of the anvil protrusion 60 with respect to the vertical direction.

[0060] When the length of the notch 54 is longer than its natural length, the end of the protrusion 55A on the notch 54 side comes into contact with the anti-rotation surface 64A facing it. Therefore, a gap G exists between the inner circumferential surface of the annular portion 53 of the set ring 50A and the outer circumferential surface of the anvil 33A, and the elastic force that causes the notch 54 to return to its natural length acts as a contact force between the protrusion 55A and the anti-rotation surface 64A. This contact force prevents the set ring 50A from rattling in the circumferential direction (reducing rattling). In other words, the anti-rotation surface 64A, which elastically contacts the protrusion 55A, functions as a third restricting portion that inhibits rattling of the set ring 50A in the circumferential direction by engaging with the protrusion 55A of the set ring 50A in the circumferential direction.

[0061] By restricting the set ring 50A from rattling in the circumferential direction, collision between the protrusion 55A of the set ring 50A and the anti-rotation surface 64A of the anvil protrusion 60A due to vibrations during operation, etc. is suppressed, wear on the set ring 50A and the anti-rotation surface 64A is suppressed, and the durability of the tool holding device is improved. Furthermore, because the anti-rotation surface 64A is inclined in the vertical direction so as to be in surface contact with the end of the protrusion 55A in the circumferential direction, wear is suppressed compared to when the edge of the end of the protrusion 55A hits it.

[0062] As another example of this embodiment, a protrusion (engagement portion) that is elastically clamped by the notch 54 of the set ring 50A may be provided on the outer periphery of the anvil 33A (the bottom surface of the set ring attachment groove 59).

[0063] [Embodiment 3] Fig. 9 is a front cross-sectional view of a tool holding device of a work machine according to embodiment 3. The cut position of the cross section in Fig. 9 is the same as the cut position of the cross section in Fig. 7. Fig. 10 is a perspective view of the anvil 33B and the set ring 50B in a separated state in embodiment 3. Fig. 11 is a perspective view of the anvil 33B and the set ring 50B in an assembled state. The following description will focus on differences from embodiment 1.

[0064] In the tool holding device of this embodiment, the anvil 33 and the set ring 50 of the tool holding device of the first embodiment are replaced with an anvil 33B and a set ring 50B, respectively.

[0065] The set ring 50B is obtained by adding a protrusion 66 to the set ring 50. The protrusion 66 protrudes forward from the annular portion 53 at a position 180° apart from the notch 54 in the circumferential direction (a position facing the notch 54 across the central axis of the anvil 33B).

[0066] The anvil 33B is obtained by adding a recess 67 into which the protrusion 66 of the set ring 50B fits, compared to the anvil 33. In other words, the anvil protrusion 60B of the anvil 33B is obtained by removing the portion corresponding to the recess 67 from the anvil protrusion 60 of the anvil 33.

[0067] Both circumferential ends of the protrusion 66 abut against the wall portions on both circumferential sides of the recess 67. This prevents the set ring 50B from rattling in the circumferential direction (reducing rattling). In other words, the recess 67 functions as a third restricting portion that prevents the set ring 50B from rattling in the circumferential direction by engaging with the protrusion 66 of the set ring 50B in the circumferential direction.

[0068] By restricting the set ring 50B from rattling in the circumferential direction, collision between the protrusion 55 of the set ring 50B and the anti-rotation surface 64 of the anvil protrusion 60B due to vibrations during operation, etc. is suppressed, wear on the set ring 50B and the anti-rotation surface 64 is suppressed, and the durability of the tool holding device is improved. Furthermore, since the wall portions on both sides of the circumferential direction of the recess 67 are inclined with respect to the left and right direction so as to be in surface contact with the end of the protrusion 66 in the circumferential direction, wear is suppressed compared to when the edge of the end of the protrusion 66 abuts against them.

[0069] [Embodiment 4] Fig. 12 is an exploded perspective view of a tool holding device for a work machine according to embodiment 4. The following description will focus on the differences from embodiment 1.

[0070] In the tool holding device of this embodiment, the anvil 33 of the tool holding device of the first embodiment is replaced with an anvil 33C, and a spring 100 is added as a second elastic member separate from the set ring 50.

[0071] The spring 100 is a wire spring and has an annular portion 103, a notch 104, and a protrusion 105. The annular portion 103 is shaped along a circle coaxial with the central axis of the anvil 33C. The notch 104 is provided in the annular portion 103. The spring 100 can elastically expand and contract in diameter by changing the length of the notch 104. The protrusion 105 extends so as to protrude radially inward from the annular portion 103. The protrusions 105 are provided on the upper and lower parts of the annular portion 103. While the set ring 50 generates a biasing force on the metal ball 39 mainly in the radially inward direction, the spring 100 generates a biasing force on the metal ball 39 mainly in the forward (axial) direction.

[0072] The anvil protrusion 60C of the anvil 33C is formed by adding a groove 69 to the outer peripheral surface of the anvil protrusion 60 of the anvil 33C, into which the annular portion 103 of the spring 100 is fitted.

[0073] Figure 13 shows a state in which the spring 100 is fitted into the groove 69 of the anvil protrusion 60C of the anvil 33C. In this state, the protrusion 105 of the spring 100 extends into the elongated hole 38 and is positioned behind the metal ball 39. Figure 14 shows a state in which the set ring 50 has been fitted into the set ring mounting groove 59 of the anvil 33C, following the state shown in Figure 13. As is clear from Figures 13 and 14, the protrusion 105 of the spring 100 passes radially inside the protrusion 55 of the set ring 50.

[0074] Figure 15 shows a state in which the guide spring 43, washer 44, and retaining ring 45 are combined from the state in Figure 14. Figure 16 is a perspective view showing the guide sleeve 40 in Figure 15. In an actual assembly process, the guide sleeve 40 is first combined in the state in Figure 14, and then the guide spring 43, washer 44, and retaining ring 45 are combined.

[0075] Fig. 17 is a side cross-sectional view of a tool holding device of embodiment 4. Fig. 18 is a side cross-sectional view of the tool holding device of Fig. 17 in a state where a bit 70 is being inserted.

[0076] As shown in Figure 17, the ranges of existence of the spring 100 and the protrusion 55 of the set ring 50 overlap in the front-to-rear direction. The protrusion 105 of the spring 100 extends into the elongated hole 38 and is positioned behind the metal ball 39, which is in the forward position, making contact with the metal ball 39 and pressing the metal ball 39 toward the forward position. As shown in Figure 18, during the process of inserting the bit 70 into the bit insertion hole 37, the metal ball 39 is pressed by the inclined portion (tapered portion) at the rear end of the bit 70, elastically deforming the protrusion 105 of the spring 100 and moving toward the rear of the elongated hole 38, and elastically deforming the set ring 50 and moving radially outward.

[0077] According to this embodiment, the spring 100 elastically biases the metal ball 39 toward the forward position, which prevents the metal ball 39 from moving rearward due to vibrations during work, etc., and the bit 70 from accidentally falling off, thereby improving the reliability of the tool holding device. Furthermore, the metal ball 39 is prevented from violently moving within the elongated hole 38 due to vibrations during work, etc., which reduces wear on the set ring 50 and the protrusions 42 and improves the durability of the tool holding device. Furthermore, because the ranges of the set ring 50 and the spring 100 overlap in the front-to-rear direction, an increase in the dimensions of the tool holding device due to the provision of the spring 100 is suppressed.

[0078] Fig. 19(A) is a perspective view of a spring 100A that can be used in place of the spring 100. Fig. 19(B) is a side view of the spring 100A. While the protrusion 105 of the spring 100 is flush with the radial annular portion 103, the protrusion 105A of the spring 100A is inclined rearward relative to the annular portion 103. This reduces the load required to insert the bit 70 and also reduces stress caused by deformation during insertion of the bit 70, improving durability.

[0079] [Embodiment 5] Fig. 20 is a perspective view of a thin flat spring 110 used in a tool holding device of a work machine according to embodiment 5. Fig. 21 is a side cross-sectional view of the tool holding device of embodiment 5. Fig. 22 is a side cross-sectional view of a state in which a bit 70 is being inserted into the tool holding device of Fig. 21. The following description will focus on differences from embodiment 1.

[0080] The tool holding device of this embodiment is provided with a thin flat spring 110 as a second elastic member separate from the set ring 50 .

[0081] As shown in FIG. 20 , the flat spring 110 has an annular portion 113, a notch 114, and a protrusion 115. The annular portion 113 is cylindrical and coaxial with the central axis of the anvil 33. The notch 114 is provided in the annular portion 113. The flat spring 110 can elastically expand and contract in diameter by changing the length of the notch 114. The protrusion 115 extends from the annular portion 113 so as to protrude forward and radially inward. The protrusions 115 are provided on the upper and lower parts of the annular portion 113. While the set ring 50 generates a biasing force on the metal ball 39 mainly in the radially inward direction, the flat spring 110 generates a biasing force on the metal ball 39 mainly in the forward (axial) direction.

[0082] As shown in FIG. 21 , the flat spring 110 is provided radially inward of the set ring 50 at a position overlapping the set ring 50 in the front-to-rear direction. The protrusion 115 of the flat spring 110 extends into the elongated hole 38 and is located rearward of the metal ball 39. As shown in FIG. 22 , during the process of inserting the bit 70 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, elastically deforming the protrusion 115 of the flat spring 110 and moving toward the rear of the elongated hole 38, while also elastically deforming the set ring 50 and moving radially outward. At this time, the portion of the annular portion 113 of the flat spring 110 from which the protrusion 115 extends elastically deforms so as to move radially outward as it approaches the front, thereby elastically deforming the set ring 50 to expand.

[0083] According to this embodiment, the flat spring 110 restricts the metal ball 39 from moving backward to such an extent that it disengages from the protrusion 42. This prevents the metal ball 39 from moving rearward due to vibrations or the like during work, which could cause the bit 70 to unexpectedly fall off, thereby improving the reliability of the tool holding device. Furthermore, because the ranges of the set ring 50 and the flat spring 110 overlap in the front-to-rear direction, an increase in the dimensions of the tool holding device due to the provision of the flat spring 110 is suppressed.

[0084] 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.

[0085] FIG. 23 is a perspective view of a spring 150 that can be used in place of the set ring 50. The spring 150 is a wire spring and has an annular portion 153, a notch 154, and a protrusion 155. The annular portion 153 is shaped along a circle coaxial with the central axis of the anvil 33. The notch 154 is provided in the annular portion 153. The spring 150 can elastically expand and contract in diameter by changing the length of the notch 154. The protrusion 155 extends so as to protrude forward from the annular portion 153. The protrusions 155 are provided on the top and bottom of the annular portion 153. The protrusions 155 function in the same manner as the protrusions 55 of the set ring 50.

[0086] The guide sleeve 40 may be a resin molded body. In this case, portions of the guide sleeve 40 that may be subject to wear due to engagement with the metal balls 39, such as the protrusions 42, may be made of metal by composite molding. The position of the elongated holes 38 may be changed to the left and right sides of the periphery of the bit insertion hole 37. The number of elongated holes 38 and metal balls 39 may be one.

[0087] 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.

[0088] DESCRIPTION OF SYMBOLS 1...Working 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...Lighting LED, 20...Motor, 21...Motor shaft, 28...Deceleration 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 (engaging member), 40...Guide sleeve, 41...Concave section, 42...Convex section (first restricting section), 43...Guide spring (biasing member), 44...Washer (spring receiving member), 45...retaining ring, 49...bearing, 50...set ring (first elastic member), 53...annular portion, 54...notch, 55...protruding portion (convex portion), 56...shaft portion, 57...wing portion, 59...set ring mounting groove, 60...anvil protrusion portion, 64...anti-rotation surface, 65...butting surface, 66...protruding portion, 67...recessed portion, 69...groove portion, 70...bit (tool tip), 72...groove portion, 80...circuit board case, 85...operation panel portion, 100...spring (second elastic member), 103...annular portion, 104...notch, 105...protruding portion, 110...flat spring (second elastic member), 113...annular portion, 114...notch, 115...protruding portion, 150...spring, 153...ring portion, 154...notch, 155...protruding portion.

Claims

1. A work machine having a motor and a tool holding device rotated by the motor, wherein the tool holding device comprises: a tool holder extending in a 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 substantially cylindrical operating member movable between a front position and a rear position on the outer periphery of the tool holder, the operating member having a first restricting portion that is located outside the engaging member in the radial direction of the tool holder when the operating member is in the rear position and the engaging member is in the forward position and restricts outward movement of the engaging member in the radial direction; and a substantially annular first elastic member that is located outside the engaging member in the radial direction when the operating member is in the rear position and the engaging member is in the rear position, the first elastic member elastically deforming when the engaging member at the rear position moves outward in the radial direction, the first elastic member having an annular portion that extends in a substantially annular shape on the outer periphery of the tool holder, the tool holder has a second restricting portion that restricts rearward movement of the operating member between the annular portion and the first restricting portion in the front-rear direction.

2. A work machine according to claim 1, wherein the second restricting portion extends radially outward from the outer periphery of the tool holder between the rear end of the elongated hole and the front end of the elongated hole in the front-to-rear direction.

3. A work machine according to claim 1, wherein the tool holder has a small diameter portion in which the elongated hole is provided and a large diameter portion connected to the rear of the small diameter portion, and the second restricting portion extends radially outward from the outer periphery of the small diameter portion.

4. A work machine as described in claim 1, characterized in that the first elastic member has a protrusion that protrudes forward from the annular portion at a position that overlaps with the long hole in the circumferential direction.

5. A work machine according to claim 4, characterized in that the second restricting portion is provided at a position overlapping the protruding portion in the front-rear direction.

6. A work machine according to claim 1, wherein the tool holder has a third restricting portion that restricts the first elastic member from rattling in the circumferential direction.

7. A work machine as described in claim 6, characterized in that the first elastic member has a protruding portion that protrudes forward from the annular portion, and the third restricting portion engages with the protruding portion in the circumferential direction, thereby preventing the first elastic member from rattling in the circumferential direction.

8. A work machine as described in claim 1, characterized in that it has a second elastic member that is provided separately from the first elastic member and is located behind the engaging member in the fore-and-aft direction when the engaging member is in the forward position, and that elastically deforms when the engaging member in the forward position moves rearward.

9. A work machine having a motor and a tool holding device rotated by the motor, wherein the tool holding device comprises: 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 substantially cylindrical operating member that is movable between a front position and a rear position on the outer periphery of the tool holder, the operating member having a first restricting portion that is located outside the engaging member in the radial direction of the tool holder when the operating member is in the rear position and the engaging member is in the front position and that restricts outward movement of the engaging member in the radial direction; and a substantially annular first elastic member that is located outside the engaging member in the radial direction when the operating member is in the rear position and the engaging member is in the rear position, the first elastic member being elastically deformed when the engaging member at the rear position moves outward in the radial direction. the first elastic member has an annular portion extending in a substantially annular shape around the outer periphery of the tool holder, and one or more protrusions protruding from the annular portion; and the tool holder has a third restricting portion that contacts one and the other circumferential sides of the one or more protrusions of the first elastic member to suppress rattling of the first elastic member in the circumferential direction.

10. A work machine according to claim 9, wherein the tool holder has a second restricting portion between the annular portion and the first restricting portion in the front-to-rear direction that restricts rearward movement of the operating member, and the third restricting portion is the end face in the circumferential direction of the second restricting portion.

11. A work machine having a motor and a tool holding device rotated by the motor, wherein the tool holding device is 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 substantially cylindrical operating member that is movable between a front position and a rear position on the outer periphery of the tool holder, the operating member having a first restricting part that is located outside the engaging member in the radial direction of the tool holder when the operating member is in the rear position and the engaging member is in the front position, and that restricts outward movement of the engaging member in the radial direction; and a substantially annular first elastic member that is located outside the engaging member in the radial direction when the operating member is in the rear position and the engaging member is in the rear position, the first elastic member elastically deforming when the engaging member at the rear position moves outward in the radial direction. a second elastic member that is provided separately from the first elastic member and is located behind the engaging member in the front-to-rear direction when the engaging member is in the forward position, and that elastically deforms when the engaging member in the forward position moves rearward.

Images