Work equipment

Abstract

To maintain a support state of a shaft well.SOLUTION: In a crank mechanism 70 of a hammer drill, a crankshaft 72 includes a press-in hole 72A opened to a down side (one side in an axial direction), and a pin 78 is pressed into the press-in hole 72A. A pin body 78A of the pin 78 is disposed inside a support hole 43D of an inner cases 42 in a radial direction. Thus, a force toward the outside in the radial direction is applied from the pin 78 to the lower end of the crankshaft 72. Thus, a pressing force for pressing the inner peripheral surface of the support hole 43D from the inside in the radial direction is applied to the lower end of the crankshaft 72 by the pin 78. Thus, in the crank mechanism 70, a supporting force (fixing force) to the crankshaft 72 can be made greater than when the pin 78 is omitted. Thus, the support state of the inner case 42 to the crankshaft 72 can be maintained well.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a working machine.

Background Art

[0002] In the working machine described in Patent Document 1 below, the driving force of a motor is transmitted to a tip tool by a transmission mechanism, and the tip tool performs drilling or the like on a workpiece. The transmission mechanism has a crank mechanism and an impact force applying mechanism, and the crank mechanism reciprocates the impact force applying mechanism in the front-rear direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the crank mechanism, there is a type in which a shaft is press-fitted into a case that houses the crank mechanism, and the crank gear (crank portion) is rotatably supported by the shaft. In this crank mechanism, the rotational force from the motor is input to the crank gear, and the impact force from the impact force applying mechanism is input to the crank portion. Therefore, if the press-fitted state (support state) of the shaft is released, the crank mechanism may not operate properly. Therefore, it is desirable for the working machine to have a structure that can maintain the support state of the shaft well.

[0005] In consideration of the above facts, an object of the present invention is to provide a working machine that can maintain the support state of the shaft well.

Means for Solving the Problems

[0006] One or more embodiments of the present invention are work machines comprising: a motor; a case having a support hole; a shaft supported in the support hole and having a press-fit hole open to one side in the axial direction; a crank portion rotatably supported on the shaft and rotating in response to the driving force of the motor; a reciprocating mechanism that reciprocates by the rotation of the crank portion and operates a tip tool; and a pin that is press-fitted into the press-fit hole and positioned radially inward of the support hole.

[0007] One or more embodiments of the present invention are a work machine in which the rotating shaft of the motor extends parallel to the shaft and is rotatably supported from the radially outer side by a motor bearing, the case is provided with a bearing retaining portion for holding the motor bearing, and in an axial view of the shaft, a part of the support hole overlaps with the bearing retaining portion.

[0008] One or more embodiments of the present invention are a work machine in which the shaft protrudes from the support hole toward the other axial side of the shaft, the bearing retainer is positioned toward the axial side of the support hole, and the pin is press-fitted into the press-fit hole from the axial side.

[0009] One or more embodiments of the present invention are working machines in which the pin comprises a press-fit portion that is press-fitted into the press-fit hole, and an annular flange portion provided at one end of the press-fit portion and extending radially outward, wherein the flange portion is positioned on one axial side of the support hole and radially outward of the bearing retaining portion, and the flange portion has a notch formed therein for positioning the bearing retaining portion.

[0010] One or more embodiments of the present invention are work machines in which at least a portion of the flange portion protrudes radially outward from the support hole.

[0011] One or more embodiments of the present invention are working machines in which the crank portion comprises a rotating body rotatably supported on the shaft, and an eccentric shaft provided on the rotating body, positioned eccentrically with respect to the axis of the shaft, and connected to the reciprocating mechanism.

[0012] One or more embodiments of the present invention are a work machine in which the other axial portion of the shaft protrudes from the support hole toward the other axial portion of the shaft, the rotating body is attached to the other axial portion of the shaft, and the pin is press-fitted into the press-fit hole from the one axial side.

[0013] One or more embodiments of the present invention are work machines in which the mechanical strength of the case is lower than the mechanical strength of the shaft.

[0014] One or more embodiments of the present invention are work machines in which the case is made of an aluminum alloy or a magnesium alloy and the shaft is made of steel.

[0015] One or more embodiments of the present invention are work machines comprising: a motor having a rotating shaft; a motor bearing that rotatably supports the rotating shaft; a bearing holder that supports the motor bearing; a case having a support hole that extends parallel to the rotating shaft and in which a portion of the rotating shaft overlaps with the bearing holder in an axial view of the rotating shaft; a shaft supported in the support hole; a crank portion that rotatably supports the shaft and rotates in response to the driving force of the motor; a reciprocating mechanism that reciprocates by the rotation of the crank portion to operate a tip tool; and a regulating member that restricts the shaft from falling out of the support hole.

[0016] One or more embodiments of the present invention are a work machine in which the shaft has a press-fit hole that is open to one side in the axial direction, the regulating member is a pin that is press-fitted into the press-fit hole, and the pin is positioned radially inward of the support hole.

[0017] One or more embodiments of the present invention are work machines in which one end and the other end of the shaft protrude from the support hole, the crank portion comprises a rotating body rotatably supported on the other end of the shaft, and an eccentric shaft provided on the rotating body, positioned eccentrically with respect to the axis of the shaft, and connected to the reciprocating mechanism, and the regulating member is a retaining ring engaged with one end of the shaft. [Effects of the Invention]

[0018] According to one or more embodiments of the present invention, the support state of the shaft can be maintained in good condition. [Brief explanation of the drawing]

[0019] [Figure 1] This is a longitudinal cross-sectional view from the right side showing a hammer drill according to this embodiment. [Figure 2] Figure 1 is a cross-sectional view showing a magnified view of the area around the crank mechanism in the hammer drill. [Figure 3] Figure 2 is a bottom view of the gear case portion of the inner case, as seen from below. [Figure 4] (A) is a bottom view corresponding to Figure 3, showing a modified example of the crankshaft support structure to the inner case shown in Figure 2, and (B) is a cross-sectional view from the right side showing the support state of the crankshaft in (A) (cross-sectional view along line 4B-4B in (A)). [Modes for carrying out the invention]

[0020] Hereinafter, the hammer drill 10 as a working machine according to the present embodiment will be described with reference to the drawings. The hammer drill 10 is configured as an electric tool for performing hole drilling or the like on a workpiece. Note that the arrows UP, FR, and RH appropriately shown in the drawings indicate the upper side, front side, and right side of the hammer drill 10. In the following description, when the up-down, front-rear, and left-right directions are used for explanation, unless otherwise specified, they indicate the up-down direction, front-rear direction, and left-right direction of the hammer drill 10. Further, in the drawings, for convenience, hatching is appropriately omitted.

[0021] As shown in FIG. 1, the hammer drill 10 includes a housing 12, a motor 34 housed in the housing 12, and a power transmission mechanism 40 that transmits the driving force of the motor 34 to the tip tool T. Further, the hammer drill 10 has a mode switching mechanism unit 66, and by operating the switching lever 67 of the mode switching mechanism unit 66, the transmission path to the tip tool T in the power transmission mechanism 40 is switched, and the hammer drill 10 is configured to switch to a hammer mode that applies an impact force to the tip tool T or a hammer drill mode that applies a rotational force and an impact force to the tip tool T. Hereinafter, each component of the hammer drill 10 will be described.

[0022] (Regarding the housing 12) The housing 12 is formed in a hollow shape and constitutes the outer shell of the hammer drill 10. The housing 12 has a main body housing 14 and a handle 16 disposed on the rear side of the main body housing 14. The main body housing 14 extends in the front-rear direction, and the rear end portion of the main body housing 14 protrudes downward. The main body housing 14 is composed of a plurality of housing members.

[0023] The handle 16 extends vertically, and its upper and lower ends are connected to the main body housing 14 by a vibration damping mechanism 18, so that the handle 16 can move relative to the main body housing 14 in the front-rear direction. The upper and lower middle portion of the handle 16 is a gripping portion 16A for the operator to grasp, and a trigger 20 is provided on the upper part of the gripping portion 16A. The trigger 20 is formed in a substantially elongated block shape that extends vertically and is exposed to the front from the gripping portion 16A so that it can be operated. The lower end of the trigger 20 is rotatably connected to the handle 16 with the left-right direction as the axial direction, so that the trigger 20 can be pulled to the rear. A switch 22 is provided inside the handle 16 behind the trigger 20. When the operator pulls the trigger 20, the switch 22 turns on. The switch 22 is electrically connected to a controller 30 provided at the lower end of the main body housing 14 and outputs an output signal to the controller 30 according to the operating state of the trigger 20.

[0024] A power cord 32 is provided at the lower end of the handle 16. The power cord 32 extends downward from the handle 16 and is configured to be connected to a commercial power supply. The power cord 32 is electrically connected to the controller 30, and power is supplied to the controller 30 from the commercial power supply via the power cord 32.

[0025] (Regarding motor 34) The motor 34 is configured as a three-phase brushless motor and is housed in the lower part of the main body housing 14 and positioned in front of the controller 30. The motor 34 includes a rotating shaft 34A with its axial direction being vertical, a substantially cylindrical rotor 34B fixed to the rotating shaft 34A, and a substantially cylindrical stator 34C positioned radially outward of the rotor 34B. The lower end of the rotating shaft 34A is rotatably supported by a motor bearing 35, and the upper end portion of the rotating shaft 34A is rotatably supported by a motor bearing 36. The motor bearing 36 is held by an inner case 42, which will be described later. A pinion gear 34A1 is formed at the upper end of the rotating shaft 34A. The motor 34 is electrically connected to the controller 30 and is driven by the controller 30.

[0026] (Regarding the power transmission mechanism 40) The power transmission mechanism 40 comprises a rotating mechanism 47, a striking mechanism 53 as a reciprocating mechanism, and a crank mechanism 70. The power transmission mechanism 40 is housed in an inner case 42, which is housed in the upper part of the main body housing 14. In the power transmission mechanism 40, the rotating mechanism 47 and the crank mechanism 70 constitute the lower part of the power transmission mechanism 40, and the striking mechanism 53 constitutes the upper part of the power transmission mechanism 40, with the rotating mechanism 47 and the crank mechanism 70 arranged side by side in the front-rear direction. The configuration of the inner case 42 will be described first, followed by a description of each component of the power transmission mechanism 40.

[0027] (Regarding Inner Case 42) The inner case 42 is made of an aluminum alloy. The rear part of the inner case 42 is configured as a gear case section 43, which is formed in a substantially concave shape that opens upwards. The front part of the inner case 42 is configured as a cylindrical case section 44, which is formed in a substantially cylindrical shape with the front-to-back direction as its axial direction and extends forward from the top of the gear case section 43. A case cover 45 is assembled to the inner case 42, and the case cover 45 closes the upper opening of the gear case section 43.

[0028] As shown in Figures 1 to 3, a bearing retaining portion 43A is provided in the middle of the front-to-back direction of the bottom of the gear case portion 43, approximately in the center in the left-to-right direction. The bearing retaining portion 43A is formed in a substantially bottomed cylindrical shape that is open to the bottom. The aforementioned motor bearing 36 is fitted into the bearing retaining portion 43A and held in the inner case 42. An insertion hole 43B is formed through the upper wall of the bearing retaining portion 43A approximately in the center. The rotating shaft 34A is inserted through the insertion hole 43B, and the pinion gear 34A1 of the rotating shaft 34A is positioned inside the lower end of the gear case portion 43.

[0029] At the bottom of the gear case 43, a support cylinder 43C is provided behind the bearing retaining portion 43A to support the crankshaft 72, which will be described later. The support cylinder 43C is formed in a substantially cylindrical shape with its vertical direction as the axial direction. The inside of the support cylinder 43C is a support hole 43D, which connects the inside and outside of the gear case 43. The support cylinder 43C is located above the lower surface of the bearing retaining portion 43A. More specifically, the lower surface of the support cylinder 43C is positioned so as to be substantially flush with the upper surface on the inner circumference side of the bearing retaining portion 43A (see Figure 2). The upper end of the support cylinder 43C protrudes above the bottom wall of the gear case 43. Also, when viewed from above, the front end of the support hole 43D overlaps with the rear end of the bearing retaining portion 43A (see Figure 3). In other words, when viewed from above, the support cylinder portion 43C and the bearing retaining portion 43A are aligned in the front-to-back direction such that the front end of the support hole 43D bites into the rear end of the bearing retaining portion 43A.

[0030] (Regarding the rotating mechanism 47) As shown in Figure 1, the rotating mechanism 47 is housed in the front part of the lower part of the gear case 43. The rotating mechanism 47 has a rotating transmission shaft 48 and a transmission gear 50. The rotating transmission shaft 48 is formed in a substantially cylindrical shape with its axial direction in the vertical direction and is positioned in front of the pinion gear 34A1 of the motor 34. The lower part of the rotating transmission shaft 48 is rotatably supported by the bottom wall of the gear case 43 via a bearing 49. A bevel gear 48A is formed at the upper end of the rotating transmission shaft 48.

[0031] The transmission gear 50 is formed in a substantially disc shape with its thickness oriented vertically, and is integrally rotatably connected to the upper end portion of the rotary transmission shaft 48. The transmission gear 50 has a slip clutch 51, which connects the transmission gear 50 to the rotary transmission shaft 48. A gear portion is formed on the outer circumference of the transmission gear 50, and this gear portion meshes with the pinion gear 34A1 of the motor 34. Furthermore, when a rotational torque exceeding a predetermined value is applied to the slip clutch 51, the connection between the rotary transmission shaft 48 and the transmission gear 50 by the slip clutch 51 is released.

[0032] (Regarding the striking mechanism 53) The striking mechanism 53 comprises a cylinder 54, a retainer sleeve 55, a ring gear 56, a clutch 58, a piston 60, a striking element 63, and an intermediate element 64.

[0033] The cylinder 54 and retainer sleeve 55 are formed in a substantially cylindrical shape with the front-to-back direction as the axial direction and are arranged coaxially. The front end of the cylinder 54 is fitted into the rear end of the retainer sleeve 55, so that the cylinder 54 and retainer sleeve 55 are connected so that they can rotate as a single unit. The cylinder 54 and retainer sleeve 55 are housed in the upper part of the gear case portion 43 and the cylindrical case portion 44 of the inner case 42. The front end of the retainer sleeve 55 protrudes forward from the inner case 42. The cylinder 54 and retainer sleeve 55 are rotatably supported by the inner case 42 and the main housing 14 via bearings. The tip tool T is attached to the front end of the retainer sleeve 55 and protrudes forward from the front end of the main housing 14.

[0034] The ring gear 56 is formed in a substantially cylindrical shape with its axial direction in the front-rear direction, and is externally fitted to the rear end portion of the cylinder 54, and is rotatably supported by the cylinder 54. A bevel gear 56A is formed at the rear end of the ring gear 56, and the bevel gear 56A meshes with the bevel gear 48A of the rotation transmission shaft 48 in the rotation mechanism 47.

[0035] The clutch 58 is formed in a substantially cylindrical shape with its axial direction in the front-rear direction and is externally fitted onto the cylinder 54 at the rear of the ring gear 56. The clutch 58 is connected to the cylinder 54 so as to be able to rotate integrally with it and move relative to it in the front-rear direction. The front end of the clutch 58 is positioned radially inward of the rear end of the ring gear 56 and engages with the ring gear 56 in the circumferential direction. As a result, the driving force of the motor 34 is transmitted to the cylinder 54 by the rotation mechanism 47, the ring gear 56, and the clutch 58, causing the cylinder 54 and the retainer sleeve 55 to rotate and impart rotational force to the tip tool T. On the other hand, when the clutch 58 is moved to the rear by the mode switching mechanism 66, the engagement between the clutch 58 and the ring gear 56 is released, and the transmission of driving force from the rotation mechanism 47 to the cylinder 54 is interrupted.

[0036] Here, the mode switching mechanism 66 has a switching lever 67 that is operably exposed upward from the main body housing 14, and the switching lever 67 is rotatably supported by the case cover 45. The mode switching mechanism 66 also has a switching arm 68 that connects the switching lever 67 and the clutch 58. When the switching lever 67 rotates, the ring gear 56 and the clutch 58 switch between an engaged state and an unengaged state, thereby switching the mode of the hammer drill 10.

[0037] The piston 60 is formed in a substantially bottomed cylindrical shape that is open to the rear and is inserted into the rear of the cylinder 54 so as to be movable relative to it in the front-rear direction. The piston 60 is also provided with a piston connecting shaft 61 whose axis is oriented in the vertical direction. The front end of a piston rod 62, which extends in the front-rear direction, is rotatably connected to the piston connecting shaft 61, and the rear end of the piston rod 62 is rotatably connected to an eccentric shaft 74B of a crank mechanism 70, which will be described later. The driving force of the motor 34 is transmitted to the piston 60 by the crank mechanism 70 and the piston rod 62, causing the piston 60 to reciprocate in the front-rear direction.

[0038] The striking element 63 is formed in a substantially cylindrical shape with its axis oriented in the front-rear direction, and is inserted into the cylinder 54 so as to be movable relative to it in the front-rear direction. The striking element 63 is positioned spaced apart in front of the piston 60, and the space between the piston 60 and the striking element 63 within the cylinder 54 is configured as an air chamber 54A.

[0039] The meson 64 is formed in a substantially cylindrical shape with its axial direction in the front-rear direction and is inserted into the retainer sleeve 55 so as to be able to move relative to it in the front-rear direction. The meson 64 is positioned adjacent to the front of the striker 63. As a result, when the piston 60 moves forward and the pressure in the air chamber 54A increases, the striker 63 and meson 64 move forward, and a striking force along the front-rear direction is applied to the tip tool T.

[0040] (Regarding the crank mechanism 70) As shown in Figures 1 to 3, the crank mechanism 70 is housed in the rear part of the gear case 43. The crank mechanism 70 consists of a crankshaft 72 as a shaft, a crank gear 74 as a crank part, and a pin 78 as a regulating member.

[0041] The crankshaft 72 is made of steel and is formed in a roughly bottomed cylindrical shape that is open to the bottom. That is, a concave press-fit hole 72A is formed inside the crankshaft 72, which is open to the bottom (one side in the axial direction). Also, the mechanical strength (tensile strength, etc.) of the inner case 42 is lower than the mechanical strength of the crankshaft 72. The outer diameter of the crankshaft 72 is set to be slightly larger than the inner diameter of the support hole 43D of the gear case portion 43. The crankshaft 72 is press-fitted into the support hole 43D of the gear case portion 43 from above and supported by the inner case 42. In the press-fitted state of the crankshaft 72, the lower surface of the crankshaft 72 is positioned to be approximately flush with the lower surface of the support cylinder portion 43C, and the upper part of the crankshaft 72 protrudes upward from the support hole 43D (support cylinder portion 43C) and is positioned inside the gear case portion 43.

[0042] The crank gear 74 has a gear body 74A and an eccentric shaft 74B as rotating bodies. The gear body 74A is formed in a substantially cylindrical shape with its vertical direction as the axial direction. The gear body 74A is fitted onto the upper part of the crankshaft 72 from above and is rotatably supported by a needle bearing 76 provided on the upper part of the crankshaft 72. A gear portion 74C is formed on the outer circumference of the lower end of the gear body 74A, and the gear portion 74C meshes with the pinion gear 34A1 of the motor 34.

[0043] The eccentric shaft 74B is formed in a substantially cylindrical shape with its axial direction in the vertical direction and protrudes upward from the upper surface of the gear body 74A. The eccentric shaft 74B is positioned eccentrically with respect to the central axis of the crankshaft 72, and the rear end of the aforementioned piston rod 62 is rotatably connected to the eccentric shaft 74B.

[0044] The pin 78 is made of steel and extends vertically as a whole. That is, the mechanical strength (tensile strength, etc.) of the inner case 42 is lower than the mechanical strength of the pin 78. The mechanical strength of the pin 78 is equivalent to that of the eccentric shaft 74B. The pin 78 consists of a pin body 78A as a press-fit portion and a flange portion 78B provided on the outer circumference of the pin body 78A. The pin body 78A is formed in a substantially cylindrical shape with the vertical direction as its axial direction, and the outer diameter of the pin body 78A is set to be slightly larger than the inner diameter of the press-fit hole 72A of the crankshaft 72. The pin body 78A is then press-fitted into the press-fit hole 72A of the crankshaft 72 from below. As a result, the pin 78 exerts a force that pushes the lower end of the crankshaft 72 radially outward. The pin body 78A is also located radially outward of the support hole 43D. In other words, the pin body 78A is positioned so as to overlap with the support hole 43D in the vertical direction. This allows the pin 78 to apply a pressing force to the lower end of the crankshaft 72, pressing the inner circumferential surface of the support hole 43D from the radially inward direction. The axial length of the portion of the pin body 78A that is press-fitted into the press-fit hole 72A is set to be shorter than the length of the support hole 43D, and also to be less than or equal to half the axial length of the crankshaft 72.

[0045] The flange portion 78B is provided at the lower end of the pin body 78A and protrudes radially outward from the pin body 78A, extending along the circumferential direction of the pin body 78A. The flange portion 78B is positioned adjacent to the lower side of the crankshaft 72 and is located radially outward from the bearing retaining portion 43A. A notch 78C is formed at the front of the flange portion 78B to avoid interference with the bearing retaining portion 43A. When viewed from below, the notch 78C is formed in a substantially arc shape that opens forward, corresponding to the outer shape of the bearing retaining portion 43A, and the rear end of the bearing retaining portion 43A is positioned inside the notch 78C. The outer diameter of the flange portion 78B is set to be larger than the inner diameter of the support hole 43D, and when viewed from below, the outer circumference of the flange portion 78B is located radially outward from the support hole 43D. That is, the outer circumference of the flange portion 78B is positioned adjacent to the lower side of the support cylinder portion 43C.

[0046] (Effects and Benefits) Next, the operation and effects of this embodiment will be described.

[0047] In the hammer drill mode of the hammer drill 10, the ring gear 56 and the clutch 58 are engaged by the mode switching mechanism 66. As a result, when the motor 34 is driven by the operator pulling the trigger 20, the crank mechanism 70 and the rotation mechanism 47 are activated, and impact force and rotation force are applied from the impact mechanism 53 to the tip tool T.

[0048] On the other hand, in hammer mode of the hammer drill 10, the clutch 58 is displaced to the rear by the mode switching mechanism 66, and the engagement between the ring gear 56 and the clutch 58 is released. As a result, when the motor 34 is driven by the operator pulling the trigger 20, the crank mechanism 70 is activated, and only the impact force is applied from the impact mechanism 53 to the tip tool T.

[0049] Furthermore, in the crank mechanism 70, the lower end of the crankshaft 72 is press-fitted into the support hole 43D of the inner case 42 and supported by the inner case 42, and the crank gear 74 is rotatably supported on the upper part of the crankshaft 72. The rotational force from the motor 34 is transmitted to the crank gear 74, and as the crank gear 74 rotates, the piston 60 of the striking mechanism 53, which is connected to the eccentric shaft 74B of the crank gear 74, moves back and forth, applying a striking force to the tip tool T. Therefore, when the crank mechanism 70 is in operation, the rotational force from the motor 34 and the striking force from the striking mechanism 53 are input to the upper part of the crankshaft 72. As a result, when the crank mechanism 70 is in operation, a force acts to pull the crankshaft 72 upward. Therefore, if the support state of the inner case 42 on the crankshaft 72 is released by this pulling force, the crank mechanism 70 may not operate normally. Furthermore, the release of support from the crankshaft 72 refers to conditions such as the crankshaft 72 becoming loose or detached.

[0050] In the crank mechanism 70, the crankshaft 72 has a press-fit hole 72A that is open to the lower side (one side in the axial direction), and a pin 78 is press-fitted into the press-fit hole 72A. As a result, a radially outward force acts from the pin 78 on the lower end of the crankshaft 72. Furthermore, the pin body 78A of the pin 78 is positioned radially inward of the support hole 43D of the inner case 42. That is, the position of the pin body 78A in the vertical direction coincides with the position of the support hole 43D in the vertical direction. As a result, the pin 78 applies a pressing force to the lower end of the crankshaft 72, pressing the inner circumferential surface of the support hole 43D from the radially inward side. Consequently, the support force (fixing force) on the crankshaft 72 can be increased in the crank mechanism 70 compared to a configuration in which the pin 78 is omitted. Therefore, the support state of the inner case 42 on the crankshaft 72 can be maintained well.

[0051] Furthermore, the rotating shaft 34A of the motor 34 is rotatably supported by a motor bearing 36, and the inner case 42 is provided with a bottomed cylindrical bearing holder 43A for holding the motor bearing 36. In addition, in a plan view, the front end of the support hole 43D overlaps with the rear end of the bearing holder 43A. This makes it possible to shorten the distance between the rotating shaft 34A and the crankshaft 72 compared to a configuration in which the bearing holder 43A and the support hole 43D do not overlap in a plan view. Consequently, the size of the crank mechanism 70 and the inner case 42 can be reduced, and consequently, the size of the hammer drill 10 can be reduced.

[0052] Furthermore, the upper part of the crankshaft 72 protrudes upward from the support hole 43D (support cylinder portion 43C), and the bearing retaining portion 43A is positioned below the support hole 43D. The pin 78 is then press-fitted into the press-fit hole 72A of the crankshaft 72 from below. As a result, even if the distance between the rotating shaft 34A and the crankshaft 72 is set to be short, the crankshaft 72 can be installed in the inner case 42 by press-fitting the crankshaft 72 into the support hole 43D from above, and the crank gear 74 can be rotatably supported by the upper part of the crankshaft 72.

[0053] Furthermore, the pin 78 is composed of a pin body 78A that is press-fitted into the press-fit hole 72A of the crankshaft 72, and a flange portion 78B provided at one end of the pin body 78A. The flange portion 78B is positioned adjacent to the lower side of the support hole 43D and is also positioned radially outward of the bearing retaining portion 43A. The flange portion 78B has a notch 78C formed therein for accommodating a part (rear end) of the bearing retaining portion 43A. As a result, if the pin 78 attempts to rotate relative to the crankshaft 72, the notch 78C and the outer circumference of the bearing retaining portion 43A engage, restricting the relative rotation of the pin 78 with respect to the crankshaft 72. Therefore, the press-fitted state of the pin 78 can be maintained in good condition.

[0054] Furthermore, the outer diameter of the flange portion 78B is set to be larger than the inner diameter of the support hole 43D, and when viewed from below, the outer circumference of the flange portion 78B is located radially outward from the support hole 43D. In other words, the outer circumference of the flange portion 78B is adjacent to the lower side of the support cylinder portion 43C. As a result, if the press-fit state of the crankshaft 72 into the support hole 43D is released and the crankshaft 72 attempts to be displaced upward by an upward tensile force acting on the crankshaft 72, the flange portion 78B will engage with the support cylinder portion 43C. Consequently, even if the press-fit state of the crankshaft 72 into the support hole 43D is released, the pin 78 will function as a retaining member, preventing the crankshaft 72 from falling out of the support hole 43D.

[0055] Furthermore, the mechanical strength of the inner case 42 is lower than that of the crankshaft 72. Specifically, the inner case 42 is made of aluminum alloy, while the crankshaft 72 is made of steel. This allows, for example, to reduce the weight of the inner case 42 while maintaining good support for the crankshaft 72.

[0056] Furthermore, the axial length of the portion of the pin body 78A that is press-fitted into the press-fit hole 72A is shorter than the vertical (axial) length of the support hole 43D, and more specifically, it is set to be less than or equal to half the axial length of the crankshaft 72. This allows the cross-sectional shape of the crankshaft 72 after the pin 78 is press-fitted to be wedge-shaped, compared to a configuration in which the pin body 78A is press-fitted over approximately the entire axial length of the press-fit hole 72A. Therefore, the so-called wedge effect effectively prevents the crankshaft 72 from coming out of the support hole 43D if the press-fit state of the crankshaft 72 in the support hole 43D is released.

[0057] In this embodiment, the pin 78, which is press-fitted into the crankshaft 72, is configured to function as a retaining member for the crankshaft 72. However, the retaining structure for the crankshaft 72 is not limited to this. For example, as shown in Figures 4(A) and (B), a retaining ring 80 may be provided on the crankshaft 72 as a restricting member, and the retaining ring 80 may be configured to function as a retaining member for the crankshaft 72.

[0058] In this case, the axial length of the crankshaft 72 is changed so that the lower end portion 72B of the crankshaft 72 protrudes below the support cylinder portion 43C of the inner case 42. In addition, in order to avoid interference between the lower end portion 72B and the bearing holding portion 43A of the inner case 42, the lower end portion 72B is made D-shaped when viewed from below. Furthermore, a locking groove 72C is formed on the outer circumference of the lower end portion 72B along the circumferential direction. The retaining ring 80 is oriented in the direction of plate thickness in the vertical direction and is formed in a substantially C-shape when viewed from above. That is, the retaining ring 80 is configured as a so-called C-ring. By inserting the retaining ring 80 into the locking groove 72C and engaging it with the locking groove 72C, and by positioning it adjacent to the lower side of the support cylinder portion 43C, the retaining ring 80 can function as a retaining member for the crankshaft 72.

[0059] Furthermore, although the inner case 42 is made of an aluminum alloy in this embodiment, the inner case 42 may also be made of a magnesium alloy. In this case as well, the weight of the inner case 42 can be reduced, and the overall weight of the hammer drill 10 can be reduced.

[0060] Furthermore, although a hammer drill was described as an example of a work implement in this embodiment, the work implement may also be a cutting tool such as a hedge trimmer or a reciprocating saw, which has a connecting part that acts as a reciprocating mechanism that moves back and forth by the rotation of a crank part to operate the blade as a tip tool. [Explanation of symbols]

[0061] 10. Hammer drill (working tool) 34 Motors 34A Rotating shaft 36 Motor bearings 42 Inner Case (Case) 43A Bearing retaining section 43D support hole 53. Striking mechanism (reciprocating mechanism) 72 Crankshaft (Shaft) 72A Press-fit hole 74 Crank gear (crank section) 74A Gear body (rotating part) 74B Eccentric shaft 78 Pins (regulating members) 78A Pin body (press-fit part) 78B Flange section 78C Notch 80 Retaining ring (regulating member) T Tip tool

Claims

1. Motor and, A case having support holes, A shaft supported by the aforementioned support hole and having a press-fit hole that is open to one side in the axial direction, A crank section is rotatably supported on the aforementioned shaft and rotates in response to the driving force of the motor, A reciprocating mechanism that moves back and forth by the rotation of the crank section to operate the tip tool, A pin is press-fitted into the press-fit hole and positioned radially inward of the support hole, A vehicle used for construction work.

2. The rotating shaft of the motor extends parallel to the shaft and is rotatably supported from the radially outer side by a motor bearing. The case is provided with a bearing retaining portion for holding the motor bearing, The work machine according to claim 1, wherein in an axial view of the shaft, a part of the support hole overlaps with the bearing holding portion.

3. The shaft protrudes from the support hole toward the other axial direction of the shaft, The bearing retaining portion is positioned on one side of the axial direction relative to the support hole. The work machine according to claim 2, wherein the pin is press-fitted into the press-fit hole from one side in the axial direction.

4. The aforementioned pin is, A press-fitting portion that is pressed into the aforementioned press-fitting hole, An annular flange portion is provided at one end of the press-fit portion and protrudes radially outward, It consists of, The flange portion is positioned on one axial side of the support hole and radially outward of the bearing holding portion. The work machine according to claim 3, wherein the flange portion has a notch formed therein for arranging the bearing retaining portion.

5. The work machine according to claim 4, wherein at least a portion of the flange portion protrudes radially outward from the support hole.

6. The aforementioned crank section is A rotating body rotatably supported on the aforementioned shaft, An eccentric shaft is provided on the rotating body, positioned eccentrically with respect to the axis of the shaft, and connected to the reciprocating mechanism, The work machine according to claim 1, comprising the above.

7. The other axial portion of the shaft protrudes from the support hole toward the other axial side of the shaft. The rotating body is attached to the other axial portion of the shaft, The work machine according to claim 6, wherein the pin is press-fitted into the press-fit hole from one side in the axial direction.

8. The work machine according to claim 7, wherein the mechanical strength of the case is lower than the mechanical strength of the shaft.

9. The aforementioned case is made of an aluminum alloy or a magnesium alloy. The work machine according to claim 8, wherein the shaft is made of steel.

10. A motor having a rotating shaft, A motor bearing that rotatably supports the aforementioned rotating shaft, A case having a bearing retaining portion that supports the motor bearing, and a support hole that extends parallel to the rotating shaft and in an axial view of the rotating shaft a portion of which overlaps with the bearing retaining portion, A shaft supported in the aforementioned support hole, A crank section is rotatably supported on the aforementioned shaft and rotates in response to the driving force of the motor, A reciprocating mechanism that moves back and forth by the rotation of the crank section to operate the tip tool, A restricting member that prevents the shaft from falling out of the support hole, A vehicle used for construction work.

11. The shaft has a press-fit hole that is open to one side in the axial direction. The regulating member is a pin that is press-fitted into the press-fit hole, The work machine according to claim 10, wherein the pin is arranged radially inward of the support hole.

12. One end and the other end portion of the shaft protrude from the support hole. The aforementioned crank section is A rotating body is rotatably supported on the other end portion of the aforementioned shaft, An eccentric shaft is provided on the rotating body, positioned eccentrically with respect to the axis of the shaft, and connected to the reciprocating mechanism, It consists of, The work machine according to claim 10, wherein the restricting member is a retaining ring engaged with one end of the shaft.

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