WO2023058513A1

WO2023058513A1 - Work machine

Info

Publication number: WO2023058513A1
Application number: PCT/JP2022/036107
Authority: WO
Inventors: 太郎岡部
Original assignee: 工機ホールディングス株式会社
Priority date: 2021-10-08
Filing date: 2022-09-28
Publication date: 2023-04-13

Abstract

The present invention improves workability while achieving reduction in size. In vibration reduction mechanisms 80 of a hammer drill 10, weight members 90 are disposed at locations, in an inner case 72, that overlap a ring gear 56 in the right-left direction and vertical direction when viewed from the front-back direction. Weight springs 96 are disposed so as to be displaced downward from the centers of gravity G of the weight members 90 when viewed from the front-back direction. More specifically, in each of the weight members 90, a spring mounting part 94 having the corresponding weight spring 96 mounted thereto and a weight part 92 serving as a weight section in which the center of gravity G is located are disposed so as to be displaced from each other in the vertical direction, and the weight part 92 extends upward from the spring mounting part 94. Accordingly, it is possible to reduce the physical size of the weight members 90 and eventually reduce the physical size of the hammer drill 10.

Description

work machine

The present invention relates to working machines.

In the work machine described in Patent Document 1 below, a gear housing is provided in an outer shell housing that constitutes the outer shell of the work machine. A power transmission mechanism is provided in the gear housing, and the power transmission mechanism applies an impact force in the front-rear direction to the tip tool. In addition, the work machine has a vibration reduction mechanism, and the vibration reduction mechanism reduces vibration generated by the power transmission mechanism. Thereby, for example, workability for workers can be improved.

WO2015/166995

However, in the working machine described above, the vibration reduction mechanism is arranged between the gear housing and the outer housing. Specifically, the vibration reduction mechanisms are arranged outside the gear housing in the left-right direction. For this reason, the size of the working machine tends to increase.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a work machine capable of improving workability while reducing the size of the machine.

One or more embodiments of the present invention include a drive source, a tip tool, and a cylindrical member connected to the drive source and the tip tool and having a first direction as an axial direction. a power transmission unit configured to apply an impact force in the first direction to the tip tool by being operated by the drive source; a case that accommodates at least the tubular member; a vibration reduction section that reduces vibration in the first direction that occurs in the case, and the vibration reduction section includes a guide member that extends in the first direction and the guide member that is relatively movable in the first direction. and a biasing member that biases the weight member in the first direction. The biasing member is arranged to overlap the cylindrical member in two directions and a third direction orthogonal to the first direction and the second direction, and the biasing member is positioned at the center of gravity of the weight member when viewed in the first direction. The working machine is arranged to be displaced in the second direction.

In one or more embodiments of the present invention, the power transmission section has a power transmission member, and the power transmission member extends relative to the tubular member in a second direction when viewed in a first direction. and at least a part of the weight member is sandwiched in the second direction by the tubular member and the power transmission member.

One or more embodiments of the present invention is a work machine in which the power transmission member is a gear having the second direction as an axial direction and transmitting rotational force to the tubular member.

In one or more embodiments of the present invention, the weight member has a curved surface extending along the circumferential direction of the tubular member.

One or more embodiments of the present invention is a work machine in which the weight member is supported by a pair of the guide members spaced apart in the second direction.

One or more embodiments of the present invention is a working machine, wherein the biasing member is a coil spring attached to the guide member.

In one or more embodiments of the present invention, a pair of the vibration reduction parts are provided inside the case, and the vibration reduction parts are arranged in one of the third directions with respect to the cylindrical member. The working machines are arranged on one side and the other side, respectively.

One or more embodiments of the present invention is a working machine in which the weight members in the pair of vibration reducing sections are connected by a weight connecting section.

In one or more embodiments of the present invention, the vibration reduction section has a holder that supports both ends of the guide member in the longitudinal direction, and the holder is supported by the biasing force of the biasing member. It is a work machine that is pressed against the wall surface of the

According to one or more embodiments of the present invention, workability can be improved while miniaturization is achieved.

It is the longitudinal cross-sectional view seen from the right side which shows the hammer drill which concerns on this embodiment. FIG. 2 is a perspective view seen diagonally from the rear left, showing a state in which the power transmission mechanism and the vibration reduction mechanism are housed in the inner case shown in FIG. 1 ; FIG. 3 is a top plan view showing a state in which the power transmission mechanism and the vibration reduction mechanism shown in FIG. 2 are accommodated in the inner case; FIG. 4 is a cross-sectional view (cross-sectional view taken along line 4-4 in FIG. 3) seen from the rear side showing a state in which the power transmission mechanism and the vibration reduction mechanism shown in FIG. 3 are housed in the inner case; FIG. 3 is an enlarged perspective view of the vibration reduction mechanism shown in FIG. 2 when it is housed in an inner case, as seen obliquely from the rear left; (A) is an enlarged perspective view showing the vibration reduction mechanism on the right side shown in FIG. 5, and (B) is a side view of the vibration reduction mechanism shown in (A) as seen from the left side. (A) is a perspective view showing a weight member of the vibration reduction mechanism shown in FIG. 6 (A), (B) is a side view of the weight member shown in (A) as seen from the left, ( C) is a rear view of the weight member shown in (A) as seen from the rear side. It is the side view seen from the left side which shows the modification 1 of the vibration reduction mechanism used for the hammer drill which concerns on this embodiment. It is the side view seen from the left side which shows the modification 2 of the vibration reduction mechanism used for the hammer drill which concerns on this embodiment. It is the perspective view seen from the diagonally rear left which shows the modification 3 of the vibration reduction mechanism used for the hammer drill which concerns on this embodiment. FIG. 11 is a cross-sectional view corresponding to FIG. 4 showing how the vibration reduction mechanism shown in FIG. 10 is accommodated in the inner case;

A hammer drill 10 as a working machine according to the present embodiment will be described with reference to FIGS. 1 to 7. FIG. The hammer drill 10 is configured as a tool for drilling or the like on a workpiece. An arrow UP, an arrow FR, and an arrow RH appropriately shown in the drawings indicate the upper side, the front side, and the right side of the hammer drill 10 . In the following description, when the up-down, front-rear, and left-right directions are used, the up-down direction, front-rear direction, and left-right direction of the hammer drill 10 are indicated unless otherwise specified. The front-back direction corresponds to the first direction of the invention, the up-down direction corresponds to the second direction of the invention, and the left-right direction corresponds to the third direction of the invention. Also, the lower side corresponds to one side in the second direction of the present invention. Furthermore, in the drawings, hatching is omitted as appropriate for the sake of convenience.

As shown in FIG. 1, the hammer drill 10 includes a housing 12, a motor 34 as a drive source accommodated in the housing 12, and a power transmission unit for transmitting the drive force of the motor 34 to the tip tool T. and a transmission mechanism 40 . Further, the hammer drill 10 has a mode switching mechanism 66, and by operating a switching lever 67 of the mode switching mechanism 66, the transmission path to the tip tool T in the power transmission mechanism 40 is switched, The hammer drill 10 is configured to be switched between a hammer mode in which the tip tool T is applied with an impact force, and a hammer drill mode in which the tip tool T is provided with a rotational force and an impact force. In addition, the hammer drill 10 has a pair of left and right vibration reduction mechanisms 80 (see FIGS. 2 and 3) as vibration reduction units. It is designed to Each configuration of the hammer drill 10 will be described below.

(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 body housing 14 and a handle 16 arranged on the rear side of the body housing 14 (one side in the front-rear direction). The body housing 14 extends in the front-rear direction, and the rear end portion of the body housing 14 protrudes downward. The body housing 14 is composed of a plurality of housing members.

The handle 16 extends vertically, and the upper and lower ends of the handle 16 are connected to the body housing 14 by a vibration isolation mechanism 20 so that the handle 16 can move relative to the body housing 14 in the front-rear direction. configured as possible. The anti-vibration mechanism 20 has a hinge connecting portion 21 that connects the lower end of the handle 16 to the main body housing 14. The hinge connecting portion 21 rotates to the rear lower end portion of the main body housing 14 with the horizontal direction as the axial direction. connected as possible. The anti-vibration mechanism 20 has an elastic connecting portion 22 that connects the upper end of the handle 16 to the body housing 14 . The elastic connecting portion 22 is made of an elastic material such as an elastomer, and is formed in a cylindrical and bellows shape whose axial direction is the front-rear direction. It is formed integrally with the body housing 14 .

The anti-vibration mechanism 20 has an anti-vibration spring 23 configured as a compression coil spring. The anti-vibration spring 23 is arranged in the elastic connecting portion 22 to move the handle 16 and the body housing 14 forward and backward. biased outward. Furthermore, the anti-vibration mechanism 20 has a stopper mechanism (not shown) to hold the handle 16 at the non-pushed position shown in FIG. The handle 16 is configured to be displaced forward from the non-pressing position by pressing the handle 16 forward during processing of the workpiece.

A vertically intermediate portion of the handle 16 is configured as a grip portion 16A that is gripped by an operator. A trigger 26 is provided on the upper portion of the grip portion 16A. The trigger 26 is formed in a substantially elongated block shape extending in the vertical direction, and is operably exposed forward from the grip portion 16A. A lower end portion of the trigger 26 is rotatably connected to the handle 16 with the lateral direction as an axial direction, and the trigger 26 is configured to be pulled rearward. A switch 28 is provided in the handle 16 behind the trigger 26 . When the operator pulls the trigger 26, the switch 28 is turned on. The switch 28 is electrically connected to a control section 30 provided at the lower end of the body housing 14 and outputs an output signal to the control section 30 according to the operating state of the trigger 26 .

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 connectable to a commercial power source. The power cord 32 is electrically connected to the control unit 30 , and power is supplied to the control unit 30 from a commercial power supply via the power cord 32 .

(Regarding the motor 34 ) The motor 34 is constructed as a three-phase brushless motor, accommodated in the lower part of the main body housing 14 , and arranged in front of the control section 30 . The motor 34 includes a drive shaft 34A whose axial direction is the vertical direction, a substantially cylindrical rotor 34B fixed to the drive shaft 34A, and a substantially cylindrical stator 34C arranged radially outside the rotor 34B. is composed of A lower end portion of the drive shaft 34A is rotatably supported by a bearing 35, and an upper end portion of the drive shaft 34A is rotatably supported by a bearing 36. As shown in FIG. A pinion gear 34A1 is formed at the upper end of the drive shaft 34A. The motor 34 is electrically connected to the controller 30 and driven under the control of the controller 30 .

(Power transmission mechanism 40 ) The power transmission mechanism 40 includes a crank mechanism portion 42 , a rotation mechanism portion 47 and a power applying mechanism portion 53 . The power transmission mechanism 40 is housed in an inner case 72 as a case, and the inner case 72 is housed in the upper part of the body housing 14 . In the power transmission mechanism 40 , the crank mechanism portion 42 and the rotation mechanism portion 47 constitute the lower portion of the power transmission mechanism 40 , the power applying mechanism portion 53 constitutes the upper portion of the power transmission mechanism 40 , and the crank mechanism portion 42 and the rotation mechanism 47 are arranged side by side in the front-rear direction. Hereinafter, first, the configuration of the inner case 72 will be described, and then each configuration of the power transmission mechanism 40 will be described.

(Regarding the inner case 72) As shown in FIGS. 1 to 5, the inner case 72 includes a case body 73 and a case cover 74. An inner case 72 is formed. A rear portion of the case main body 73 is configured as a gear case portion 73A, and the gear case portion 73A is formed in a generally concave shape that opens upward. The front portion of the case main body 73 is configured as a cylindrical case portion 73B. The cylindrical case portion 73B is formed in a substantially cylindrical shape whose axial direction is the front-rear direction, and extends forward from the upper portion of the gear case portion 73A. is served. The case cover 74 is formed in a substantially plate shape with the plate thickness direction extending in the vertical direction, and is assembled to the upper opening of the gear case portion 73A to close the opening. A bearing 36 for supporting the drive shaft 34A of the motor 34 is fixed to the bottom wall of the gear case portion 73A, and the pinion gear 34A1 of the drive shaft 34A is arranged in the lower end portion of the gear case portion 73A.

(Regarding the crank mechanism part 42) As shown in Fig. 1, the crank mechanism part 42 is accommodated in the rear part of the gear case part 73A. The crank mechanism portion 42 has a crankshaft 43 and a crank gear 44 . The crankshaft 43 is formed in a generally bottomed cylindrical shape that opens downward, is arranged behind the pinion gear 34A1 of the motor 34, and the lower end of the crankshaft 43 is fixed to the bottom wall of the gear case portion 73A. It is The crank gear 44 is formed in a substantially cylindrical shape whose axial direction is the vertical direction, and is rotatably supported by the crank shaft 43 via a bearing 45 . A gear portion is formed on the outer peripheral portion of the lower end portion of the crank gear 44 , and the gear portion is meshed with the pinion gear 34 A 1 of the motor 34 . A connection shaft 44A projecting upward is provided at the upper end of the crank gear 44, and the connection shaft 44A is arranged at a position eccentric to the center of the crankshaft 43. As shown in FIG.

(Regarding the Rotation Mechanism 47) As shown in FIGS. 1 and 4, the rotation mechanism 47 is accommodated in the front portion of the gear case portion 73A. The rotation mechanism portion 47 has a rotation shaft 48 and a transmission gear 50 as a power transmission member. The rotating shaft 48 is formed in a substantially columnar shape with an axial direction extending in the vertical direction, and is arranged on the front side of the pinion gear 34A1 of the motor 34. rotatably supported. A bevel gear 48A is formed at the upper end of the rotary shaft 48. As shown in FIG.

The transmission gear 50 is formed in a substantially disk shape with the plate thickness direction extending in the vertical direction, and is connected to the upper end side portion of the rotating shaft 48 so as to be integrally rotatable. The transmission gear 50 has a slip clutch 51 by which the transmission gear 50 and the rotating shaft 48 are connected. Specifically, a recess opening downward is formed in the lower surface of the transmission gear 50, and a slip clutch 51 is disposed in the recess to connect the transmission gear 50 and the rotating shaft 48. there is A gear portion is formed on the outer peripheral portion of the transmission gear 50 , and the gear portion is meshed with the pinion gear 34 A 1 of the motor 34 . Further, when a rotational torque equal to or greater than a predetermined value acts on the slip clutch 51, the connection state between the rotary shaft 48 and the transmission gear 50 by the slip clutch 51 is released. That is, the slip clutch 51 is configured as a so-called torque limiter mechanism so that the motor 34 is not overloaded by the slip clutch 51 . In addition, the transmission gear 50 forms the outermost portion of the power transmission mechanism 40 in the left-right direction. That is, in the power transmission mechanism 40, the transmission gear 50 is configured as the largest member in the left-right direction. Thus, the maximum lateral dimension of the inner case 72 (gear case portion 73A) is set by the diameter of the transmission gear 50. As shown in FIG.

(About power application mechanism 53) As shown in FIGS. 1 to 4, the power application mechanism 53 includes a cylinder 54, a retainer sleeve 55, a ring gear 56 as a tubular member, a clutch 58, a piston 60 , a striker 63 , and a meson 64 .

The cylinder 54 and the retainer sleeve 55 are formed in a substantially cylindrical shape whose axial direction is the front-rear direction, and are arranged coaxially. A front end portion of the cylinder 54 is fitted into a rear end portion of the retainer sleeve 55 so that the cylinder 54 and the retainer sleeve 55 are connected so as to be rotatable together. The cylinder 54 and the retainer sleeve 55 are housed in the upper portion of the gear case portion 73A of the inner case 72 and the cylindrical case portion 73B. More specifically, the rear end portion of the cylinder 54 is arranged above the rotation mechanism portion 47 and in front of the connecting shaft 44A in the crank mechanism portion 42 . On the other hand, the front end of the retainer sleeve 55 protrudes forward beyond the inner case 72 . The cylinder 54 and the retainer sleeve 55 are rotatably supported by the inner case 72 and the body housing 14 via bearings. A tip tool T is attached to the front end of the retainer sleeve 55 and protrudes forward from the front end of the body housing 14 .

The ring gear 56 is formed in a substantially cylindrical shape whose axial direction is the front-rear direction, is externally inserted in the rear end portion of the cylinder 54 , and is rotatably supported by the cylinder 54 . Specifically, the ring gear 56 is arranged above the transmission gear 50 and housed in the gear case portion 73A. A bevel gear 56A is formed at the rear end portion of the ring gear 56, and the bevel gear 56A meshes with the bevel gear 48A of the rotating shaft 48 of the rotating mechanism portion 47. As shown in FIG. The rear end portion of the ring gear 56 is bent radially outward in a substantially crank-like shape and protrudes radially outward compared to other portions of the ring gear 56 when viewed in vertical cross section. Further, the axis AL1 of the transmission gear 50 described above passes through the axis AL2 of the ring gear 56 (cylinder 54). Furthermore, the outermost diameter dimension of the ring gear 56 is set to be smaller than the diameter of the transmission gear 50 (see FIG. 4), and the ring gear 56 is located in the upper portion of the power transmission mechanism 40 (the power applying mechanism portion 53) in the left-right direction. It constitutes the outermost part.

The clutch 58 is formed in a substantially cylindrical shape whose axial direction is the front-rear direction, and is externally fitted on the cylinder 54 on the rear side of the ring gear 56 . Clutch 58 is splined to cylinder 54 . That is, the clutch 58 is connected to the cylinder 54 so as to be rotatable together and relatively movable in the front-rear direction. The front end of the clutch 58 is arranged radially inside 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 rotating mechanism portion 47, the ring gear 56, and the clutch 58, and the cylinder 54 and the retainer sleeve 55 are rotated to impart a rotational force to the tip tool T. ing. On the other hand, the clutch 58 is disengaged from the ring gear 56 by moving the clutch 58 rearward by the mode switching mechanism 66, which will be described later, so that the drive force is not transmitted from the rotation mechanism 47 to the cylinder 54. It is configured to be blocked.

As shown in FIG. 1, the piston 60 is formed in a generally bottomed cylindrical shape that is open rearward, and is inserted into the rear portion of the cylinder 54 so as to be relatively movable in the front-rear direction. Further, the piston 60 is provided with a piston connecting shaft 61 whose axial direction is the vertical direction. A front end portion of a piston rod 62 extending in the front-rear direction is rotatably connected to the piston connecting shaft 61, and a rear end portion of the piston rod 62 is rotatably connected to the connecting shaft 44A of the crank mechanism portion 42. Concatenated. As a result, the driving force of the motor 34 is transmitted to the piston 60 by the crank mechanism 42 and the piston rod 62, and the piston 60 reciprocates in the front-rear direction.

The striker 63 is formed in a substantially columnar shape whose axial direction is the front-rear direction, and is inserted into the cylinder 54 so as to be relatively movable in the front-rear direction. The striker 63 is spaced in front of the piston 60, and the space between the piston 60 and the striker 63 in the cylinder 54 is configured as an air chamber 54A.

The intermediate element 64 is formed in a substantially columnar shape whose axial direction is the front-rear direction, and is inserted into the retainer sleeve 55 so as to be relatively movable in the front-rear direction. The intermediate element 64 is arranged adjacent to the front side of the striking element 63 . As a result, the piston 60 moves forward and the pressure in the air chamber 54A rises, so that the striker 63 and the intermediate member 64 move forward, and a striking force is applied to the tip tool T in the front-rear direction. It is configured to

(Regarding the Mode Switching Mechanism 66 ) The mode switching mechanism 66 includes a switching lever 67 and a switching arm 69 .

The switching lever 67 is formed in a substantially bottomed cylindrical shape that opens downward, is disposed at the rear end of the main body housing 14 , and is exposed upward from the main body housing 14 so as to be operable. A lever shaft 68 is fixed to the central portion of the switching lever 67 . The lever shaft 68 is formed in a substantially columnar shape with an axial direction extending in the vertical direction, and protrudes downward from the switching lever 67 . A lever shaft 68 is rotatably supported by a case cover 74 of the inner case 72 .

The switching arm 69 is formed in a substantially elongated shape extending in the front-rear direction. A front end of the switching arm 69 is connected to the clutch 58 of the power applying mechanism 53 , and a rear end of the switching arm 69 is connected to the lever shaft 68 via an arm connecting shaft 70 . The arm connecting shaft 70 is arranged eccentrically with respect to the central axis of the lever shaft 68 . As a result, the switching arm 69 is displaced in the front-rear direction by rotating the switching lever 67 . Specifically, in the hammer drill mode of the hammer drill 10, the switching arm 69 is arranged at the position shown in FIG. 1, and the ring gear 56 and the clutch 58 are engaged. On the other hand, although not shown, in the hammer mode of the hammer drill 10, by rotating the switching lever 67, the switching arm 69 is displaced rearward and the engagement state between the ring gear 56 and the clutch 58 is released. It's becoming

(Regarding the Vibration Reduction Mechanism 80) As shown in FIGS. 3 and 4, the pair of left and right vibration reduction mechanisms 80 are accommodated in both left and right end portions of the gear case portion 73A of the inner case 72, respectively. Specifically, a pair of left and right vibration reduction mechanisms 80 are housed in spaces S on both sides of the ring gear 56 in the left and right direction above the transmission gear 50 in the gear case portion 73A. The pair of left and right vibration reduction mechanisms 80 are configured symmetrically with respect to the central portion of the inner case 72 in the left-right direction. Therefore, in the following description, the vibration reduction mechanism 80 on the right side will be described, and the description of the vibration reduction mechanism 80 on the left side will be omitted as appropriate.

As shown in FIGS. 2 to 7, the vibration reduction mechanism 80 includes a pair of front and rear holders 82, an upper guide shaft 84 and a lower guide shaft 86 as guide members, a weight member 90, and front and rear guide shafts as urging members. and a pair of weight springs 96 .

(Regarding holders 82) The pair of holders 82 are formed in a substantially rectangular plate shape with the thickness direction in the front-rear direction and the longitudinal direction in the vertical direction, and constitute both ends of the vibration reduction mechanism 80 in the front-rear direction. The lower end of the holder 82 is engaged with the inner case 72 in the front-rear direction and the left-right direction, and the upper end of the holder 82 is engaged with the case cover 74 in the front-rear direction and the left-right direction to be fixed to the inner case 72 . It is The front holder 82 is urged forward by a front weight spring 96, which will be described later, and the rear holder 82 is urged rearward by a rear weight spring 96 to form a pair of holders 82. are pressed against the wall surface of the case body 73 . Thereby, the fixed state of the holder 82 (vibration reduction mechanism 80) is maintained.

A pair of left and right upper bearing portions 82A are formed on the upper portions of the pair of front and rear holders 82 . The upper bearing portion 82A is formed in a substantially cylindrical shape whose axial direction is the front-rear direction, and protrudes inward in the front-rear direction from the holder 82 . Below the pair of holders 82, a lower bearing portion 82B is formed. Similarly to the upper bearing portion 82A, the lower bearing portion 82B is formed in a substantially cylindrical shape whose axial direction is the front-rear direction, and protrudes from the holder 82 inward in the front-rear direction. In addition, the positions of the upper bearing portion 82A and the lower bearing portion 82B in the left-right direction are set so that the lower bearing portion 82B is arranged between the pair of left and right upper bearing portions 82A when viewed from the front-rear direction. there is

(Regarding the Upper Guide Shaft 84 and the Lower Guide Shaft 86) The upper guide shaft 84 and the lower guide shaft 86 are formed in a substantially columnar shape whose axial direction is the front-rear direction. Both ends in the longitudinal direction of the upper guide shaft 84 are fitted into the upper bearing portions 82A on the left-right outer side (that is, on the right side) of the holder 82, and the upper guide shaft 84 is held by the pair of front and rear holders 82. there is Both ends of the lower guide shaft 86 in the longitudinal direction are fitted into the lower bearing portions 82B of the holder 82 so that the lower guide shaft 86 is held by the pair of front and rear holders 82 . In other words, the lower guide shaft 86 is arranged laterally inward (toward the ring gear 56 ) with respect to the upper guide shaft 84 . The upper guide shaft 84 is arranged slightly below the axis AL2 of the ring gear 56 when viewed in the front-rear direction. Further, ring dampers 88 are externally inserted on both ends of the upper guide shaft 84 in the front-rear direction. The ring damper 88 is made of an elastic material such as rubber, and serves as a member that mitigates collision between a weight member 90 and an upper bearing portion 82A of the holder 82, which will be described later.

(Regarding Weight Member 90 ) The weight member 90 includes a weight portion 92 forming an upper portion of the weight member 90 and a spring mounting portion 94 forming a lower portion of the weight member 90 .

The weight portion 92 is formed in a substantially inverted T-shaped block shape when viewed from the left-right direction, with the left-right direction being the thickness direction. An upper guide hole 92A is formed through the lower end portion of the weight portion 92 in the front-rear direction. The upper guide shaft 84 is inserted into the upper guide hole 92A, and the weight portion 92 is supported by the upper guide shaft 84 so as to be relatively movable in the front-rear direction. Further, the center of gravity G (see FIG. 4) of the weight member 90 is arranged at a position overlapping the weight portion 92 when viewed from the front-rear direction. Specifically, the center of gravity G of the weight member 90 is positioned near the upper guide hole 92A when viewed from the front-rear direction.

The spring mounting portion 94 is formed in a plate-like shape with the thickness direction extending in the front-rear direction, and extends downward from the central portion in the front-rear direction of the weight portion 92 . Further, the spring mounting portion 94 is formed with a pair of front and rear mounting cylinder portions 94A for mounting a weight spring 96, which will be described later. The mounting cylinder portion 94A is formed in a cylindrical shape whose axial direction is the front-rear direction, and protrudes outward from the spring mounting portion 94 in the front-rear direction. The inside of the mounting cylinder portion 94A is configured as a lower guide hole 94B, and the lower guide hole 94B penetrates in the front-rear direction so that the insides of the pair of front and rear mounting cylinder portions 94A communicate with each other. The lower guide shaft 86 is inserted into the lower guide hole 94B, and the spring mounting portion 94 is supported by the lower guide shaft 86 so as to be relatively movable in the front-rear direction. As a result, in the weight member 90, the spring mounting portion 94 for mounting the weight spring 96 and the weight portion 92 functioning as a weight portion are arranged to be shifted in the vertical direction.

Here, the weight member 90 is arranged close to the right side of the ring gear 56, and substantially the entire weight member 90 overlaps the ring gear 56 in the left-right direction (see FIG. 4). Specifically, the upper end of the weight member 90 is arranged below the uppermost end of the ring gear 56, and the lower end of the weight member 90 is arranged slightly below the lowermost end of the ring gear 56. Further, the position of the weight member 90 in the front-rear direction is set so that the entire weight member 90 overlaps the transmission gear 50 when viewed from above.

Further, the outer shape of the spring mounting portion 94 is formed in a substantially circular shape centered on the lower guide hole 94B when viewed from the front-rear direction, and the outer peripheral surface of the weight portion 92 and the outer peripheral surface of the spring mounting portion 94 are aligned. connected smoothly. Specifically, a curved surface 90A is formed on the left-right inner side surface of the weight member 90 (that is, the left side surface, which faces the ring gear 56 in the radial direction). The curved surface 90A is curved in an arc centered on the axis AL2 of the ring gear 56 when viewed from the front-rear direction, and is formed at the lower portion of the weight portion 92 and the upper portion of the spring mounting portion 94. Smoothly connected to the bottom surface.

That is, in the weight member 90 , a portion of the spring mounting portion 94 projects leftward from the weight portion 92 and is arranged to bite into the space S between the ring gear 56 and the transmission gear 50 . In other words, the weight member 90 extends vertically along the circumferential direction of the ring gear 56 on the right side of the ring gear 56 . As a result, the outermost portion of the ring gear 56 (the portion where the bevel gear 56A is formed) and part of the weight member 90 overlap in the vertical direction. A side surface 90</b>B on the left-right direction outer side of the weight member 90 is formed in a planar shape along a plane orthogonal to the left-right direction, and is smoothly connected to the lower surface of the spring mounting portion 94 . The side surfaces 90B of the weight member 90 are arranged close to the left and right side surfaces of the gear case portion 73A.

(Regarding weight springs 96) A pair of front and rear weight springs 96 are configured as compression coil springs. The weight spring 96 is arranged outside the spring mounting portion 94 of the weight member 90 in the front-rear direction, and is attached to the lower guide shaft 86 on the lower side. Specifically, the rear end portion of the weight spring 96 on the front side is externally fitted on the mounting cylinder portion 94A on the front side, and the front end portion of the weight spring 96 on the front side is externally fitted on the lower bearing portion 82B of the holder 82 on the front side. ing. On the other hand, the front end portion of the rear weight spring 96 is fitted over the rear mounting cylinder portion 94A, and the rear end portion of the rear weight spring 96 is fitted over the lower bearing portion 82B of the rear holder 82. It is As a result, the weight spring 96 is arranged at a position shifted downward with respect to the weight portion 92 (the center of gravity G of the weight member 90). In other words, the center AL3 of the weight spring 96 is arranged at a position different from the center of gravity G of the weight member 90 when viewed in the front-rear direction. In other words, the center of gravity G of the weight member 90 is arranged outside the arrangement range of the weight spring 96 when viewed in the front-rear direction. Also, although the lower guide shaft 86 is inserted through the weight spring 96, there is a gap between the lower guide shaft 86 and the weight spring 96 that is equal to the thickness of the mounting tubular portion 94A and the lower bearing portion 82B. direction is provided.

The weight spring 96 on the front side urges the spring mounting portion 94 rearward, the weight spring 96 on the rear side urges the spring mounting portion 94 frontward, and the weight member 90 moves the upper guide shaft 84 and the lower guide. It is held at the central portion of the shaft 86 in the front-rear direction. The radius of the weight spring 96 is set slightly smaller than the radius of the spring mounting portion 94 of the weight member 90, and is set so that the weight spring 96 does not protrude beyond the spring mounting portion 94 when viewed from the front-rear direction. ing.

(Function and effect) Next, the function and effect of this embodiment will be described.

In the hammer drill mode of the hammer drill 10 , the switching arm 69 of the mode switching mechanism 66 engages the ring gear 56 and the clutch 58 . As a result, when the motor 34 is driven by the operator pulling the trigger 26, the crank mechanism 42 and the rotation mechanism 47 are actuated, and the impact force and the rotation force are applied to the tip tool T from the power application mechanism 53. be.

On the other hand, in the hammer mode of the hammer drill 10, the clutch 58 is displaced rearward by the switching arm 69 of the mode switching mechanism 66, and the engagement state between the ring gear 56 and the clutch 58 is released. Accordingly, when the operator pulls the trigger 26 to drive the motor 34 , the crank mechanism 42 is operated and only the impact force is applied to the tip tool T from the power applying mechanism 53 .

In both the hammer drill mode and the hammer mode of the hammer drill 10, an impact force in the front-rear direction is applied to the tip tool T due to the operation of the power transmission mechanism 40. As shown in FIG. As a result, vibrations generated when the power transmission mechanism 40 operates are transmitted to the inner case 72 .

Here, in the hammer drill 10 , the vibration reduction mechanism 80 is provided inside the inner case 72 . The vibration reduction mechanism 80 has a weight member 90, and the weight member 90 is supported by a pair of upper and

lower guide shafts

84 and 86 so as to be relatively movable in the front-rear direction. The weight member 90 is biased in the front-rear direction by a pair of front and rear weight springs 96 . As a result, the vibration energy transmitted to the inner case 72 can be absorbed by the vibration reduction mechanism 80 by the weight member 90 vibrating in the longitudinal direction when the power transmission mechanism 40 is operated. Therefore, since the vibration transmitted to the operator is reduced, the workability of the hammer drill 10 can be improved.

Further, the weight member 90 is arranged in the inner case 72 at a position overlapping the ring gear 56 in the left-right direction and the up-down direction when viewed in the front-rear direction. is shifted downward with respect to the center of gravity G. Specifically, the weight member 90 has a spring attachment portion 94 to which a weight spring 96 is attached, and a weight portion 92 functioning as a weight portion where the center of gravity G is located, which are arranged with a vertical shift. extends upward from the spring mounting portion 94 . As a result, the size of the weight member 90 can be reduced, and the size of the hammer drill 10 can be reduced.

Hereinafter, this point will be described while comparing with the weight of the comparative example. The weight of the comparative example is formed in a cylindrical shape whose axial direction is the front-rear direction. In other words, in the weight of the comparative example, the weight portion functioning as a weight portion and the spring mounting portion for mounting the weight spring 96 are not displaced in the vertical direction. When the weight member of the comparative example is movably connected to the upper guide shaft 84 or the lower guide shaft 86 and biased by the pair of front and rear weight springs 96 so as to sandwich the weight member of the comparative example from the outside in the front-rear direction. In order to secure the weight in the weight member, it is necessary to increase the size of the weight member. For example, in the weight member of the comparative example, if the size of the weight member is increased in the radial direction, it is necessary to increase the size of the inner case 72 in the lateral direction and the vertical direction. Further, for example, in the weight member of the comparative example, if the size of the weight member is increased in the longitudinal direction, it is necessary to increase the size of the inner case 72 in the longitudinal direction. As a result, the size of the hammer drill 10 may increase.

In contrast, in the present embodiment, as described above, the weight member 90 is arranged in the inner case 72 at a position overlapping the ring gear 56 in the left-right direction and the up-down direction when viewed from the front-rear direction. Also, in the weight member 90, a spring attachment portion 94 to which a weight spring 96 is attached and a weight portion 92 functioning as a weight portion are arranged so as to be displaced in the vertical direction. That is, the weight member 90 can extend vertically along the circumferential direction of the ring gear 56 on the outer side of the ring gear 56 in the left-right direction. Therefore, the size of the weight member 90 can be reduced compared to the weight member of the comparative example, and the size of the hammer drill 10 can be reduced. As described above, the hammer drill 10 can be downsized and the workability can be improved.

As another comparative example, a configuration in which the vibration reduction mechanism 80 is provided outside the inner case 72 is considered. In another comparative example, since the wall surface of the inner case 72 is interposed between the space in the inner case 72 in which the power transmission mechanism 40 is accommodated and the space in which the vibration reduction mechanism 80 is accommodated, the weight member 90 can be moved vertically. It is difficult to arrange so as to overlap the ring gear 56 in the direction and the left-right direction. In addition, since a separate outer wall is provided outside the space in which the vibration reduction mechanism 80 is accommodated, the size of the hammer drill 10 may increase. On the other hand, in the present embodiment, both the vibration reduction mechanism 80 and the power transmission mechanism 40 are accommodated in the inner case 72, so the weight member 90 is arranged so as to overlap the ring gear 56 in the vertical and horizontal directions. In addition, there is no need to provide an outer wall other than the inner case 72, and the size of the hammer drill 10 can be reduced.

In the weight member 90 , the weight portion 92 is arranged outside the ring gear 56 (cylinder 54 ) in the left-right direction, and the spring mounting portion 94 is arranged below the weight portion 92 . More specifically, when viewed from the front-rear direction, the weight portion 92 where the center of gravity G of the weight member 90 is located is arranged slightly below the axis AL2 of the ring gear 56 (cylinder 54), and the spring mounting portion 94 is located at the weight portion. It is arranged below 92. As a result, in the weight member 90, the center of gravity G of the weight member 90 is arranged closer to the axis line AL2 in the vertical direction than in a configuration in which the positions of the weight portion 92 and the spring mounting portion 94 are reversed vertically. be able to. That is, compared to a configuration in which the weight portion 92 is movably connected to the lower guide shaft 86 and the spring mounting portion 94 is movably connected to the upper guide shaft 84, the vertical direction of the center of gravity G of the weight member 90 from the axis AL2 is higher. can be reduced. As a result, the center of gravity G of the weight member 90 can be arranged laterally outside the cylinder 54 that accommodates the piston 60 and the striker 63 that apply the striking force in the longitudinal direction to the tip tool T. As shown in FIG. Therefore, the vibration reduction effect of the vibration reduction mechanism 80 can be enhanced.

The power transmission mechanism 40 also has a transmission gear 50 . When viewed from the front-rear direction, the transmission gear 50 extends in the left-right direction below the ring gear 56 , and at least a portion of the weight member 90 is vertically sandwiched between the ring gear 56 and the transmission gear 50 . there is Specifically, the spring mounting portion 94 of the weight member 90 protrudes from the weight portion 92 toward the ring gear 56 , and the protruding portion is vertically sandwiched between the ring gear 56 and the transmission gear 50 . . As a result, the part between the ring gear 56 and the transmission gear 50 in the space S of the gear case portion 73A can be used to dispose a part of the spring mounting portion 94 and the weight spring 96. FIG. Therefore, it is possible to prevent the weight spring 96 from projecting outward in the left-right direction from the weight member 90 while ensuring the diameter (spring diameter) of the weight spring 96 .

A curved surface 90A is formed on the inner side surface of the weight member 90 in the left-right direction. Thereby, the weight of the weight member 90 can be ensured while the weight member 90 is arranged close to the ring gear 56 . As a result, it is possible to effectively contribute to miniaturization of the weight member 90 in the lateral direction.

The weight member 90 is supported by a pair of upper guide shaft 84 and lower guide shaft 86 so as to be relatively movable in the front-rear direction. Thereby, the weight member 90 can be arranged along the circumferential direction of the ring gear 56 while stabilizing the posture of the weight member 90 .

Also, the weight spring 96 is a compression coil spring attached to the lower guide shaft 86 . As a result, the posture of the weight spring 96 can be stabilized by the lower guide shaft 86, and the weight spring 96 can bias the weight member 90 in the front-rear direction.

Further, in the hammer drill 10 , a pair of left and right vibration reduction mechanisms 80 are provided in the inner case 72 , and the vibration reduction mechanisms 80 are arranged on both sides in the left and right direction with respect to the ring gear 56 . As a result, vibrations transmitted to the inner case 72 during operation of the power transmission mechanism 40 can be absorbed in a well-balanced manner by the pair of vibration reduction mechanisms 80 .

The vibration reduction mechanism 80 also includes a pair of front and rear holders 82 that support both ends of the upper guide shaft 84 and the lower guide shaft 86 in the longitudinal direction. is pressed against the gear case portion 73A. As a result, the urging force of the weight spring 96 that urges the weight member 90 in the front-rear direction can be utilized to keep the holder 82 firmly fixed to the inner case 72 .

In addition, since the vibration reduction mechanism 80 is also arranged in the inner case 72 in which the power transmission mechanism 40 is accommodated, the power transmission mechanism 40 is also installed when the inner case 72 is opened for maintenance of the power transmission mechanism 40. Therefore, maintenance of the hammer drill 10 is improved. Furthermore, the lubricant such as grease applied to the power transmission mechanism 40 to lubricate the power transmission mechanism 40 can scatter to the vibration reduction mechanism 80 during driving, so the power transmission mechanism 40 is also lubricated. Wear and the like are less likely to occur, improving reliability.

(Modification of Vibration Reduction Mechanism 80) Next, a modification of the vibration reduction mechanism 80 will be described.

(Modification 1 of Vibration Reduction Mechanism 80) Modification 1 of the vibration reduction mechanism 80 will be described below with reference to FIG. Modification 1 of vibration reduction mechanism 80 is configured in the same manner as vibration reduction mechanism 80 of the present embodiment except for the following points. Note that FIG. 8 shows the vibration reduction mechanism 80 arranged on the right side, and in FIG. attached.

In Modified Example 1 of the vibration reduction mechanism 80 , the upper guide shaft 84 is omitted from the vibration reduction mechanism 80 , and the weight member 90 is supported only by the lower guide shaft 86 . The lower guide shaft 86 is formed in a non-circular shape when viewed from its longitudinal direction. In this modified example, the lower guide shaft 86 is formed to have a substantially track-shaped cross section.

In the weight member 90, the upper guide hole 92A is omitted, and the lower guide hole 94B is formed in an elongated hole shape corresponding to the outer shape of the lower guide shaft 86. As shown in FIG. Thereby, the weight member 90 is connected to the lower guide shaft 86 so as to be relatively movable in the front-rear direction and not relatively rotatable.

In the first modification of the vibration reduction mechanism 80, similarly to the present embodiment, the weight member 90 is arranged radially outside the ring gear 56 along the circumferential direction of the ring gear 56, and the weight spring 96 is attached to the ring gear 56 side, and the weight spring 96 can be arranged below the center of gravity G of the weight member 90 and closer to the ring gear 56 side. Therefore, in the first modification of the vibration reduction mechanism 80 as well, the hammer drill 10 can be downsized and the workability can be improved.

Further, in the first modification of the vibration reduction mechanism 80, the upper guide shaft 84 is omitted from the vibration reduction mechanism 80. As shown in FIG. Therefore, it is possible to reduce the number of parts and the number of assembly man-hours, and contribute to the cost reduction of the vibration reduction mechanism 80 .

(Modification 2 of Vibration Reduction Mechanism 80) Modification 2 of the vibration reduction mechanism 80 will be described below with reference to FIG. Modification 2 of vibration reduction mechanism 80 is configured in the same manner as vibration reduction mechanism 80 of the present embodiment except for the following points. Note that FIG. 9 shows the vibration reduction mechanism 80 arranged on the right side, and in FIG. attached.

In the second modification of the vibration reduction mechanism 80 , the lower guide shaft 86 is omitted from the vibration reduction mechanism 80 and the weight member 90 is supported only by the upper guide shaft 84 . As with the lower guide shaft 86 in the first modification of the vibration reduction mechanism 80, the upper guide shaft 84 is formed in a non-circular shape when viewed from its longitudinal direction.

In the weight member 90, the lower guide hole 94B is omitted, and the upper guide hole 92A is formed in an elongated hole shape corresponding to the outer shape of the upper guide shaft 84. As shown in FIG. Thereby, the weight member 90 is connected to the upper guide shaft 84 so as to be relatively movable in the front-rear direction and not relatively rotatable.

In the second modification of the vibration reduction mechanism 80, similarly to the present embodiment, the weight member 90 is arranged radially outside the ring gear 56 along the circumferential direction of the ring gear 56, and the weight spring 96 is attached to the ring gear 56 side, and the weight spring 96 can be arranged below the center of gravity G of the weight member 90 and closer to the ring gear 56 side. Therefore, in the second modification of the vibration reduction mechanism 80 as well, the hammer drill 10 can be downsized and the workability can be improved.

Further, in the second modification of the vibration reduction mechanism 80, the upper guide shaft 84 is omitted from the vibration reduction mechanism 80. As shown in FIG. Therefore, it is possible to reduce the number of parts and the number of assembly man-hours, and contribute to the cost reduction of the vibration reduction mechanism 80 .

(Modification 3 of Vibration Reduction Mechanism 80) Modification 3 of the vibration reduction mechanism 80 will be described below with reference to FIGS. 10 and 11. FIG. Modification 3 of vibration reduction mechanism 80 is configured in the same manner as vibration reduction mechanism 80 of the present embodiment except for the following points. In FIGS. 10 and 11, the same reference numerals are given to the parts configured in the same manner as the vibration reduction mechanism 80 of the present embodiment.

In Modified Example 3 of the vibration reduction mechanism 80, a connection arm 98 is provided as a weight connection portion for connecting the weight members 90 of the pair of left and right vibration reduction mechanisms 80 to each other. The connecting arm 98 is arranged above the ring gear 56 and has a substantially semi-disc shape that opens downward along the circumferential direction of the ring gear 56 . Both longitudinal ends of the connecting arm 98 are connected to the upper end of the weight member 90 . As a result, in the third modification of the vibration reduction mechanism 80, the pair of left and right vibration reduction mechanisms 80 operate integrally.

In the third modification of the vibration reduction mechanism 80, similarly to the present embodiment, the weight member 90 is arranged radially outside the ring gear 56 along the circumferential direction of the ring gear 56, and the weight spring 96 is attached to the ring gear 56 side, and the weight spring 96 can be arranged below the center of gravity G of the weight member 90 and closer to the ring gear 56 side. Therefore, also in the modification 3 of the vibration reduction mechanism 80, workability|operativity can be improved, achieving size reduction of the hammer drill 10. FIG.

Further, in the third modification of the vibration reduction mechanism 80, the pair of left and right vibration reduction mechanisms 80 can be operated integrally by the connecting arm 98. FIG. Further, since the left and right weight members 90 are connected by the connection arm 98, the weight of the left and right weight members 90 can be made heavier than in the present embodiment. Therefore, for example, the weight of the weight member 90 as a whole can be adjusted according to the resonance frequency during operation of various hammer drills. Therefore, it is possible to absorb vibrations generated during operation in correspondence with various hammer drills.

DESCRIPTION OF SYMBOLS 10... Hammer drill (working machine), 34... Motor (drive source), 40... Power transmission mechanism (power transmission part), 50... Transmission gear (power transmission member), 56... Ring gear (cylindrical member), 72... Inner case (Case) 80 Vibration reduction mechanism (vibration reduction portion) 82 Holder 84 Upper guide shaft (guide member) 86 Lower guide shaft (guide member) 90 Weight member 90A Curved surface 96 ... Weight spring (biasing member), 98 ... Connection arm (weight connection part), G ... Center of gravity of weight member, T ... Tip tool

Claims

a driving source;
a tip tool;
It is connected to the drive source and the tip tool and includes a cylindrical tubular member having a first direction as an axial direction. a power transmission unit that imparts an impact force;
a case that houses at least the tubular member;
a vibration reduction unit that is housed inside the case and reduces vibration in the first direction that occurs in the case;
with
The vibration reduction unit is
a guide member extending in the first direction;
a weight member supported by the guide member so as to be relatively movable in the first direction;
a biasing member that biases the weight member in the first direction;
consists of
The weight member is arranged to overlap the cylindrical member in a second direction orthogonal to the first direction and a third direction orthogonal to the first direction and the second direction when viewed from the first direction. ,
In the working machine, the biasing member is arranged to be displaced in the second direction with respect to the center of gravity of the weight member when viewed in the first direction.
The power transmission unit has a power transmission member,
When viewed in the first direction, the power transmission member extends in the third direction on one side in the second direction with respect to the tubular member, and at least a portion of the weight member is the tubular member and the power transmission member. The work machine according to claim 1, wherein the work machine is sandwiched in the second direction by the transmission member.
The working machine according to claim 2, wherein the power transmission member is a gear having the second direction as an axial direction and transmitting a rotational force to the cylindrical member.
The working machine according to any one of claims 1 to 3, wherein the weight member has a curved surface extending along the circumferential direction of the tubular member.
The working machine according to any one of claims 1 to 4, wherein the weight member is supported by a pair of the guide members spaced apart in the second direction.
The working machine according to any one of claims 1 to 5, wherein the biasing member is a coil spring attached to the guide member.
A pair of said vibration reducing parts are provided inside said case, and said vibration reducing parts are arranged on one side and the other side of said cylindrical member in said third direction, respectively. The work machine according to any one of claims 1 to 6.
The working machine according to claim 7, wherein the weight members in the pair of vibration reducing sections are connected by a weight connecting section.
The vibration reducing section has a holder that supports both ends of the guide member in the longitudinal direction, and the holder is pressed against the wall surface of the case by the biasing force of the biasing member. Item 8. The work machine according to any one of Items 8.