JP2017119329A - Striking work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a striking work machine of which large-sizing of a housing can be suppressed.SOLUTION: A striking work machine 10 having: a retainer sleeve which supports a tip tool; a cylinder 35 which is located concentrically with the retainer sleeve; a piston 44 which is movable located in the cylinder 35; a striking element 45 which is movable located in the cylinder 35; and a pressure chamber B1 which is formed in the cylinder 35 between the piston 44 and the striking element 45. The striking work machine further has: a first breathing hole 47 which radially penetrates the cylinder 35; a mass body 55 which is located outside the cylinder 35; a contact part 60 which is provided on the mass body 55; and elastic members 56, 57 which are located outside the cylinder 35, and energize the mass body 55. When the mass body 55 most approach the retainer sleeve in a center line A1 direction, a place at which the contact part 60 contacts an external surface of the cylinder 35 in the center line A1 direction is between the first breathing hole 47 and the piston 44.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an impact working machine that impacts a tool with the power of a motor.

  A conventional striking work machine includes a motor provided in a housing, a cylinder provided in the housing, a piston provided in the cylinder and reciprocatingly driven by the power of the motor, a striker provided in the cylinder, and a cylinder. And a pressure chamber provided between the piston and the striking element and generating a striking force. The hitting machine is described in Patent Document 1.

  The striking work machine described in Patent Literature 1 has a housing, and the housing has a striking case, a motor case, and a gear case. The cylinder, the piston and the striker are arranged concentrically in the strike case. A motor is provided in the motor case, and a motion conversion mechanism for converting the rotational force of the motor into the reciprocating force of the piston is provided in the gear case. The housing is provided with a continuous handle, and the gear case is disposed between the striking case and the handle in the direction of movement of the piston. A vibration reduction mechanism is provided in the gear case. The vibration reduction mechanism is a mechanism that reduces vibration of the housing, and the vibration reduction mechanism includes a weight portion, a rotation shaft, a support portion, and a leaf spring. In the impact working machine described in Patent Literature 1, when the housing vibrates due to the reciprocating motion of the tool, the weight portion and the support portion swing relative to the rotating shaft and the housing.

JP 2008-272897 A

  However, the impact working machine described in Patent Document 1 has a problem that the housing is increased in size in the operation direction of the piston because the vibration reduction mechanism is provided between the handle and the gear case.

  An object of the present invention is to provide an impact working machine capable of suppressing the housing from becoming large in the direction of operation of the piston.

  An impact working machine according to an embodiment includes a cylindrical support member that supports a tip tool, a cylinder that is concentrically arranged with the support member, and a cylinder that is movable in the direction of the center line of the cylinder. A piston formed in the cylinder so as to be movable in the direction of the center line, and formed between the piston and the hammer in the cylinder. A striking work machine having a pressure chamber, a first breathing hole that penetrates the cylinder in a radial direction and connects the inside and the outside of the cylinder, and the outside of the cylinder, and A mass body movable in the center line direction; a contact portion provided on the mass body and in contact with an outer surface of the cylinder; and disposed outside the cylinder; and the mass body in the center line direction In An elastic member that urges, and when the mass body is closest to the support member in the center line direction, the location where the contact portion contacts the outer surface of the cylinder in the center line direction is 1 between the breathing hole and the piston.

  In the hitting work machine, the mass body is disposed outside the cylinder, and is operable in the center line direction. Therefore, it can suppress that a housing becomes large in the moving direction of a piston.

It is sectional drawing which looked at the whole impact working machine from the side. It is sectional drawing which looked at the principal part of the striking work machine from the side. It is sectional drawing which looked at the principal part of the striking work machine from the side. It is sectional drawing which looked at the principal part of the striking work machine from the side. It is sectional drawing which looked at the principal part of the striking work machine from the side. It is sectional drawing which looked at the principal part of the striking work machine from the side. It is sectional drawing which looked at the principal part of the striking work machine from the side.

  Hereinafter, an embodiment of an impact working machine will be described in detail with reference to the drawings. Among the configurations shown in the drawings, the same configurations are denoted by the same reference numerals.

  The striking work machine 10 shown in FIG. 1 performs a striking operation by pressing the tip tool 11 against the target object 12 to process the target object 12. The object 12 may be concrete, brick, stone, or asphalt. Moreover, the process performed on the target object 12 includes crushing the target object 12, scraping the surface of the target object 12, cutting the target object 12, and forming a groove in the target object 12. And the tool 11 which has the shape suitable for the material of the target object 12 and the process to perform is used for the front-end tool 11. In the present embodiment, an example in which concrete as the object 12 is crushed by the tip tool 11 will be described. For this reason, the tip tool 11 shown in FIG. 1 is shown in a wedge shape for convenience.

  The striking work machine 10 has a housing 13, and the housing 13 has a motor case 14, a striking case 15, and a gear case 16. The motor case 14, the striking case 15, and the gear case 16 are fixed to each other with a screw member. The striking work machine 10 has an electric motor 17 as a power source, and the electric motor 17 is disposed in the motor case 14.

  Further, a handle portion 18 connected to the motor case 14 and the gear case 16 is provided. The handle portion 18 is a portion that is gripped by a hand when an operator uses the impact work machine 10, and a power cable 19 is attached to the handle portion 18. The power cable 19 is connected to a power supply unit, for example, a commercial power supply or a battery. A controller 20 is provided in the housing 13, and the controller 20 is connected to the power cable 19 by a lead wire and connected to the electric motor 17 by a lead wire. Further, a trigger 21 and a trigger switch 22 are provided in the handle portion 18, and the trigger switch 22 is connected to the controller 20 by a lead wire. When the operator grasps the handle portion 18 and operates the trigger 21 and the trigger switch 22 is turned on, the electric power of the power source portion is supplied to the electric motor 17 and the electric motor 17 is driven. When the trigger switch 22 is turned off, the electric motor 17 stops.

  The electric motor 17 includes a stator 23 and a rotor 24, and a rotating shaft 25 that rotates together with the rotor 24 is provided. The rotary shaft 25 is rotatably supported by a bearing 26. A gear 27 is provided on the outer periphery of the rotary shaft 25. A crankshaft 28 and a connecting rod 29 are provided in the housing 13. The crankshaft 28 is rotatably supported by a bearing 30. A gear 31 fixed to the crankshaft 28 is provided, and the gear 31 meshes with the gear 27. The number of teeth of the gear 31 is larger than the number of teeth of the gear 27, and the gears 27 and 31 serve as a speed reduction mechanism when transmitting the rotational force of the rotating shaft 25 to the crankshaft 28. Further, a disc portion 32 is provided coaxially with the crankshaft 28 at the end of the crankshaft 28, and a pin 33 is provided at a position eccentric from the center of the disc portion 32.

  The striking case 15 has a cylindrical shape, and a first end portion in the longitudinal direction of the striking case 15 is fixed to the gear case 16. A cylindrical cylinder holder 34 is provided in the striking case 15, and a cylinder 35 is provided in the cylinder holder 34. The cylinder holder 34 and the cylinder 35 are disposed concentrically on a common center line A1. A retainer sleeve 36 is disposed from the inside to the outside of the cylinder holder 34. The retainer sleeve 36 has a cylindrical shape, and the retainer sleeve 36 is disposed concentrically with the cylinder 35. The cylinder holder 34, the cylinder 35, and the retainer sleeve 36 are fixed so as not to move in the direction of the center line A1 with respect to the striking case 15.

  The retainer sleeve 36 has a large diameter hole 37 and a small diameter hole 38 that are arranged concentrically. The inner diameter of the large diameter hole 37 is larger than the inner diameter of the small diameter hole 38. The large diameter hole 37 is disposed between the small diameter hole 38 and the cylinder 35 in the direction of the center line A1. An inclined surface 39 that connects the inner surface of the large-diameter hole 37 and the inner surface of the small-diameter hole 38 is provided. The tip tool 11 is inserted into the small diameter hole 38. The retainer sleeve 36 is a support member that supports the tip tool 11.

  A front cover 40 is attached to the second end of the striking case 15 in the longitudinal direction. The front cover 40 has a cylindrical shape, and a cylindrical grip 41 is attached in front of the front cover 40. The front cover 40 and the grip 41 are disposed on the radially outer side of the retainer sleeve 36. An intermediate element 42 is provided across the large-diameter hole 37 of the retainer sleeve 36 and the cylinder 35. The meson 42 is movable in the direction of the center line A1 and is made of metal. The meson 42 can contact or leave the tip tool 11. The meson 42 has an axial shape and is provided with a large diameter portion 43 in which the outer diameter of the meson 42 is partially increased. When the large diameter portion 43 comes into contact with the inclined surface 39, the intermediate element 42 does not move in the direction of the center line A1 in a direction approaching the tip tool 11.

  As shown in FIG. 2, a piston 44 is provided inside the cylinder 35, and the piston 44 can reciprocate in the direction of the center line A <b> 1 inside the cylinder 35. An O-ring 65 as a seal member is attached to the outer periphery of the piston 44. The O-ring 65 is made of rubber, and the O-ring 65 contacts the inner peripheral surface of the cylinder 35 to form a seal surface. As shown in FIG. 1, the piston 44 is connected to the pin 33 by a connecting rod 29. The rotating shaft 25 of the electric motor 17 is connected to the piston 44 by a crankshaft 28, a pin 33 and a connecting rod 29. When the rotational force of the rotary shaft 25 is transmitted to the crankshaft 28 and the crankshaft 28 rotates, the piston 44 reciprocates in the cylinder 35.

  As shown in FIG. 2, the striker 45 is disposed between the piston 44 and the intermediate element 42 in the direction of the center line A1 inside the cylinder 35. The striker 45 is made of metal, and the striker 45 can move in the direction of the center line A1. An O-ring 46 as a seal member is attached to the outer periphery of the striker 45, and the O-ring 46 contacts the inner peripheral surface of the cylinder 35 to form a seal surface.

  Inside the cylinder 35, a pressure chamber B1 is formed between the striker 45 and the piston 44. The piston 44 operates to increase the pressure in the pressure chamber B1 to drive the striker 45, and the impact force is transmitted to the tip tool 11 via the intermediate element 42. A first breathing hole 47 and a second breathing hole 48 penetrating the cylinder 35 in the radial direction are provided. Both the first breathing hole 47 and the second breathing hole 48 are connected to the inside of the cylinder 35. A space C1 is formed between the cylinder 35 and the cylinder holder 34, and the first breathing hole 47 and the second breathing hole 48 are connected to the space C1.

  The first breathing hole 47 is located between the retainer sleeve 36 and the second breathing hole 48 in the direction of the center line A1. The opening diameter of the first breathing hole 47 is larger than the opening diameter of the second breathing hole 48. A plurality of first breathing holes 47 are arranged at intervals in the circumferential direction of the cylinder 35. The number of the first breathing holes 47 may be either singular or plural. The number of first breathing holes 47 is larger than the number of second breathing holes 48. When a plurality of second breathing holes 48 are provided, the second breathing holes 48 are arranged at intervals in the circumferential direction of the cylinder 35. The number of the second breathing holes 48 in the present embodiment is singular.

  Inside the cylinder holder 34, a damper holder 49, a damper 50 and a washer 51 are provided between the cylinder 35 and the retainer sleeve 36. The damper 50 is made of rubber, and the damper holder 49 and the washer 51 are made of metal. The damper holder 49, the damper 50, and the washer 51 are both annular, and a part of the intermediate element 42 is disposed in the damper holder 49, the damper 50, and the washer 51. The damper 50 is disposed between the damper holder 49 and the washer 51 in the direction of the center line A1. The large diameter portion 43 of the meson 42 is disposed between the washer 51 and the inclined surface 39 in the direction of the center line A1.

  The cylinder holder 34 supports the stopper ring 52, and the gear case 16 supports the stopper ring 53. The cylinder 35 is disposed between the stopper ring 53 and the damper holder 49 in the direction of the center line A1. The stopper rings 52 and 53 determine the positions of the cylinder 35, the retainer sleeve 36, the damper holder 49, the damper 50, and the washer 51 in the direction of the center line A1.

  Next, a usage example of the impact work machine 10 will be described. Here, an example will be described in which the striking work machine 10 is used in a state where the meson 42 is positioned above the tip tool 11 in the direction of gravity. When an operator grasps the handle portion 18 and holds the striking work machine 10 and presses the tip tool 11 against the object 12 as shown in FIG. 1, the reaction force against the pressing force is transmitted to the intermediate element 42, and the large diameter portion 43 is washed. The tip tool 11 and the intermediate element 42 are stopped by being pressed against 51.

  Further, the position where the O-ring 46 comes into contact with the inner peripheral surface of the cylinder 35 in a state where the tip tool 11 is pressed against the object 12 is the first breathing hole 47 and the piston 44 in the center line A1 direction as shown in FIG. Between. For this reason, the O-ring 46 blocks the pressure chamber B <b> 1 and the first breathing hole 47. Further, the position where the O-ring 65 contacts the inner peripheral surface of the cylinder 35 is between the second breathing hole 48 and the crankshaft 28 in the direction of the center line A1 regardless of the position of the piston 44.

  When the operator operates the trigger 21 to turn on the trigger switch 22 and the rotating shaft 25 of the electric motor 17 rotates, the piston 44 reciprocates in the direction of the center line A1. When the piston 44 moves away from the retainer sleeve 36 as shown in FIG. 3, the pressure in the pressure chamber B1 becomes lower than the pressure in the space C1, and the air in the space C1 passes through the second breathing hole 48 and enters the pressure chamber B1. Inhaled. Further, the striker 45 is separated from the retainer sleeve 36 after the time when the piston 44 is separated from the retainer sleeve 36.

  After the piston 44 reaches the position farthest from the retainer sleeve 36, that is, the top dead center, the piston 44 operates so as to approach the retainer sleeve 36. The pressure in the pressure chamber B <b> 1 increases rapidly in a stroke in which the piston 44 operates in a direction approaching the retainer sleeve 36. In the stroke in which the piston 44 moves toward the retainer sleeve 36, a part of the air in the pressure chamber B1 passes through the second breathing hole 48 and is discharged into the space C1.

  The striker 45 is driven in a direction approaching the retainer sleeve 36 due to a rapid increase in the pressure in the pressure chamber B1, and strikes the intermediate element 42. The striking force received by the meson 42 is transmitted to the tip tool 11, and the tip tool 11 crushes the object 12. After reaching the position where the piston 44 is closest to the retainer sleeve 36, that is, the bottom dead center, the piston 44 moves away from the retainer sleeve 36.

  Thereafter, the striking work machine 10 repeats the operation of transmitting the striking force of the striking element 45 to the tip tool 11 while the piston 44 reciprocates in the direction of the center line A1 while the rotating shaft 25 of the electric motor 17 is rotating. .

  When the operator removes the tip tool 11 from the object 12, the intermediate element 42 moves by its own weight in the direction of the center line A1, the large diameter portion 43 contacts the inclined surface 39, and the intermediate element 42 stops. Further, the striker 45 comes into contact with the intermediate element 42 by the pressure of the pressure chamber B1 and stops as shown in FIG. When the striker 45 stops at the position shown in FIG. 4, the O-ring 46 comes into contact with the inner peripheral surface of the cylinder 35 between the first breathing hole 47 and the retainer sleeve 36 in the direction of the center line A1, and the pressure chamber B1 Connected to one breathing hole 47.

  For this reason, even if the electric motor 17 is driven and the piston 44 reciprocates in the cylinder 35, the air in the pressure chamber B1 is discharged from the first breathing hole 47 to the space C1, and the pressure in the pressure chamber B1 increases rapidly. Never do. Therefore, it is possible to prevent the striker 45 from hitting the tip tool 11 in a state where the tip tool 11 is away from the object 12, that is, idling.

  By the way, when the impact force of the striker 45 is transmitted to the tip tool 11 while the tip tool 11 is pressed against the object 12, the reaction force is generated by the intermediate element 42, the washer 51, the damper 50, the damper holder 49, and the cylinder 35. And transmitted to the housing 13 via the stopper ring 53. Further, when the piston 44 reciprocates within the cylinder 35, the inertial force due to the reciprocating motion of the cylinder 35 is transmitted to the housing 13 via the connecting rod 29, the pin 33, the crankshaft 28 and the bearing 30. For this reason, the housing 13 vibrates in the direction of the center line A1.

  The impact work machine 10 has a vibration reduction mechanism 54. The vibration reduction mechanism 54 suppresses vibration of the housing 13, and the vibration reduction mechanism 54 includes a mass body 55 disposed in the space C <b> 1 and elastic members 56 and 57 disposed in the space C <b> 1. The elastic members 56 and 57 are both compression coil springs. The elastic members 56 and 57 can be compressed in the direction of the center line A1. The mass body 55 is made of metal and has a cylindrical shape. The mass body 55 is arranged on the outer side of the cylinder 35 in the radial direction with the center line A1 as the center, and the mass body 55 is movable in the direction of the center line A1 with respect to the cylinder 35.

  The mass body 55 has grooves 58 and 59 provided at both ends in the direction of the center line A1. The grooves 58 and 59 are annularly provided on the inner periphery of the mass body 55, and the contact portion 60 is provided between the groove 58 and the groove 59. That is, the grooves 58 and 59 are disposed on both sides of the contact portion 60 in the direction of the center line A1. The inner diameters of the grooves 58 and 59 are the same, and the inner diameters of the grooves 58 and 59 are larger than the inner diameter of the contact portion 60. The contact portion 60 contacts the outer surface of the cylinder 35 and suppresses the mass body 55 from moving in the radial direction of the cylinder 35. The total length of the mass body 55 in the direction of the center line A1 is larger than the total length of the contact portion 60. The total length of the mass body 55 in the center line A1 direction is smaller than the shortest distance between the first breathing hole 47 and the second breathing hole 48.

  Both of the elastic members 56 and 57 are metal compression coil springs and can be expanded and contracted in the direction of the center line A1. Further, the elastic members 56 and 57 have the same spring constant. A snap ring 61 is attached to the inner periphery of the cylinder holder 34, and the elastic member 56 is disposed between the mass body 55 and the snap ring 61 in the direction of the center line A1. An annular plate 62 is provided in the cylinder holder 34. The plate 62 is disposed between the damper holder 49 and the mass body 55 in the direction of the center line A1. A ring 63 is disposed between the plate 62 and the damper holder 49.

  The elastic members 56 and 57 are both disposed in the space C1 in a state where they have received a compressive force in the direction of the center line A1. The elastic members 56 and 57 are provided on both sides of the mass body 55 in the direction of the center line A1. The elastic member 56 urges the mass body 55 in a direction to approach the retainer sleeve 36. The elastic member 57 urges the mass body 55 in a direction away from the retainer sleeve 36.

  The operation of the vibration reduction mechanism 54 will be described. When the housing 13 does not vibrate in the direction of the center line A1, the mass body 55 is positioned between the first breathing hole 47 and the second breathing hole 48 in the direction of the center line A1, as shown in FIG. That is, the first breathing hole 47 is connected to the space C1, and the second breathing hole 48 is connected to the space C1.

  When an impact work is performed by the impact work machine 10 and the housing 13 vibrates in the direction of the center line A1, the mass body 55 moves in a phase opposite to the direction in which the housing 13 moves. For example, when the housing 13 moves away from the object 12, the mass body 55 moves in a direction approaching the retainer sleeve 36 against the urging force of the elastic member 57 as shown in FIG. 5.

  In a state where the mass body 55 is closest to the retainer sleeve 36, a part of the mass body 55 overlaps with the arrangement region of the first breathing hole 47 in the radial direction of the cylinder 35. For example, as shown in FIG. 5, when the elastic member 57 is in a fully compressed state, the mass body 55 is closest to the retainer sleeve 36. The total compression state of the elastic member 57 means a state in which the elastic deformation amount of the elastic member 57 is maximized with respect to the compression load in the direction of the center line A1. In other words, even if a more compressive load is applied to the elastic member 57, it does not elastically deform beyond the fully compressed state. The state in which the mass body 55 is closest to the retainer sleeve 36 is a temporary state during vibration of the housing 13, and the mass body 55 does not stop at the position shown in FIG.

  Further, the fact that a part of the mass body 55 overlaps with the arrangement region of the first breathing hole 47 in the radial direction of the cylinder 35 has the following meaning. That is, when the arrangement area of the mass body 55 and the arrangement area of the first breathing hole 47 are projected in the radial direction of the cylinder 35, a part of the arrangement area of the mass body 55 and the arrangement area of the first breathing hole 47 overlap. It means that. It is also possible to grasp that a part of the arrangement region of the mass body 55 in the direction of the center line A1 overlaps with the arrangement region of the first breathing hole 47 in the direction of the center line A1.

  However, the place where the contact portion 60 contacts the outer surface of the cylinder 35 is between the first breathing hole 47 and the second breathing hole 48 in the direction of the center line A1. In other words, regardless of the position of the piston 44 in the direction of the center line A1, the contact portion 60 contacts the outer surface of the cylinder 35 between the piston 44 and the first breathing hole 47. That is, the contact part 60 does not block the first breathing hole 47, and the first breathing hole 47 is connected to the space C <b> 1 by the groove 59. For this reason, when the tip tool 11 is moved away from the object 12 and the striker 45 moves in a direction closer to the retainer sleeve 36 from the position shown in FIG. 5, the pressure chamber B1 is connected to the first breathing hole 47, so Can be prevented.

  On the other hand, when the housing 13 moves in the direction approaching the object 12 during the striking work by the striking work machine 10, the mass body 55 resists the urging force of the elastic member 56 as shown in FIG. Move away from.

  In the impact working machine 10 of the embodiment, even when the mass body 55 is farthest from the retainer sleeve 36, the contact portion 60 is located between the first breathing hole 47 and the second breathing hole 48 in the direction of the center line A1. To do. That is, the contact portion 60 does not block the second breathing hole 48, and the second breathing hole 48 is connected to the space C1 by the groove 58. For this reason, the mass body 55 does not hinder the action of the air in the space C1 being sucked into the pressure chamber B1 through the second breathing hole 48 in the stroke in which the piston 44 moves away from the retainer sleeve 36. Further, in the stroke in which the piston 44 moves toward the retainer sleeve 36, the mass body 55 does not hinder the action of a part of the air in the pressure chamber B1 passing through the second breathing hole 48 and being discharged into the space C1. Therefore, the mass body 55 does not prevent the second breathing hole 48 from adjusting the pressure in the pressure chamber B1.

  The state in which the mass body 55 is farthest from the retainer sleeve 36 is, for example, a state in which the elastic deformation amount of the elastic member 56 is maximized as shown in FIG. The state in which the mass body 55 is farthest from the retainer sleeve 36 is a temporary state during the vibration of the housing 13, and the mass body 55 does not stop at the position shown in FIG.

  The total length of the mass body 55 in the direction of the center line A <b> 1 is larger than the total length of the contact portion 60, and the mass body 55 does not block the first breathing hole 47 and the second breathing hole 48. For this reason, according to the vibration mode or natural frequency of the housing 13, the total length of the mass body 55 in the direction of the center line A1 can be changed, and the mass of the mass body 55 can be set. Therefore, the vibration reduction effect by the vibration reduction mechanism 54 can be enhanced.

  Furthermore, a lubricant, for example, grease for lubrication or lubricating oil is enclosed in the housing 13. The lubricant lubricates the meshing position of the gear 27 and the gear 31, the operating position of the bearings 26 and 30, the sliding position of the piston 44 and the cylinder 35, and the sliding position of the mass body 55 and the cylinder 35. Since the grooves 58 and 59 provided in the mass body 55 can hold the lubricant, the performance of lubricating the sliding portion between the mass body 55 and the cylinder 35 can be improved.

  As described above, in the impact work machine 10, the space C1 is connected to the first breathing hole 47 regardless of the position of the mass body 55 with respect to the cylinder 35 in the direction of the center line A1, and the space C1 is pressurized by the second breathing hole 48. Connected to room B1. A space C1 is provided between the cylinder 35 and the cylinder holder 34, and the vibration reducing mechanism 54 is disposed in the space C1. For this reason, the space for providing the vibration reduction mechanism 54 does not have to be provided exclusively in the housing 13. Therefore, the housing 13 can be prevented from becoming large in the direction of the center line A1, that is, in the operation direction of the piston 44.

  Another example of a stopper that restricts the range in which the mass body 55 operates in the direction of the center line A1 is shown in FIG. A stopper 64 is provided between the first breathing hole 47 and the second breathing hole 48 on the outer peripheral surface of the cylinder 35. A groove along the circumferential direction is provided on the outer peripheral surface of the cylinder 35, and the stopper 64 is attached to the groove. The stopper 64 is a metal annular body, and the outer diameter of the stopper 64 is smaller than the inner diameter of the groove 59 and larger than the inner diameter of the contact portion 60. When the mass body 55 moves in the direction of the center line A1, the stopper 64 enters and exits the groove 59. When the mass body 55 operates in a direction approaching the retainer sleeve 36 and the contact portion 60 comes into contact with the stopper 64, the mass body 55 cannot approach the retainer sleeve 36 any more.

  When the mass body 55 is closest to the retainer sleeve 36, that is, when the contact portion 60 comes into contact with the stopper 64, the first breathing hole 47 is connected to the space C <b> 1 by the groove 59. For this reason, when the mass body 55 is in the state closest to the retainer sleeve 36, when the tip tool 11 moves away from the object 12 and the striker 45 moves in a direction approaching the retainer sleeve 36, the pressure chamber B1 is The first breathing hole 47 is connected to the space C1. Therefore, even if the piston 44 moves in a direction approaching the retainer sleeve 36, it is possible to prevent idling. In FIG. 7, the state in which the mass body 55 is closest to the retainer sleeve 36 is a temporary state during the vibration of the housing 13, and the mass body 55 does not stop at the position shown in FIG. In FIG. 7, the inner diameter of the compression coil spring used as the elastic member 57 is larger than the outer diameter of the stopper 64. Therefore, when the stopper 64 comes out of the groove 59, the stopper 64 does not contact the elastic member 57. In this case, by making the inner diameters of the elastic members 56 and 57 the same, the spring constants of the elastic members 56 and 57 are made the same.

  Further, FIGS. 5 to 7 are views for explaining the position of the mass body 55 with respect to the first breathing hole 47 and the second breathing hole 48 in the direction of the center line A1. For this reason, during the operation of the piston 44, the relative position between the piston 44 and the mass body 55 may not coincide with the relative position between the piston 44 and the mass body 55 shown in any of FIGS. Further, the position where the striker 45 moves and the O-ring 46 contacts the inner surface of the cylinder 35 may be between the piston 44 and the second breathing hole 48.

  The striking work machine is not limited to the above embodiment, and various modifications can be made without departing from the gist thereof. For example, the notch provided in the mass body to connect the breathing hole and the space includes a chamfered portion provided at a corner of the inner peripheral end of the mass body in addition to the grooves 58 and 59. The chamfered portion has a slope inclined with respect to the center line A1. Moreover, the regulating member that regulates the range in which the mass body operates in the direction approaching the retainer sleeve includes a stopper attached to the inner peripheral surface of the cylinder holder in addition to the stopper attached to the outer peripheral surface of the cylinder.

  The tip tool may rotate by receiving the rotational force of the electric motor. In this case, it is possible to set a plurality of modes such as an impact mode in which the tip tool is operated by the impact force of the striker, a rotation mode in which the tip tool rotates by receiving the rotational force of the electric motor, and a mode in which the tip tool performs the impact while rotating . The operator can switch between a plurality of modes.

  Further, the electric motor may be either a brush motor or a brushless motor. The power supply unit that supplies power to the electric motor is not only an AC power supply or DC power supply that is provided separately from the impact work machine, but also a DC power supply provided inside the housing or provided outside the housing, and is detachable from the housing. Including a direct current power supply. The crankshaft and connecting rod are conversion mechanisms that convert the rotational force of the motor into the reciprocating force of the piston. As the conversion mechanism, a cam mechanism can be used instead of the crankshaft and the connecting rod.

  As the power source, an engine can be used instead of the electric motor. The engine is a power source that burns fuel and converts heat energy into kinetic energy, and the engine includes a gasoline engine, a diesel engine, and a liquefied propane gas engine.

  DESCRIPTION OF SYMBOLS 4 ... Piston, 10 ... Blow working machine, 11 ... Tip tool, 12 ... Object, 13 ... Housing, 14 ... Motor case, 15 ... Blow case, 16 ... Gear case, 17 ... Electric motor, 18 ... Handle part, 19 ... Power cable, 20 ... Controller, 21 ... Trigger, 22 ... Trigger switch, 23 ... Stator, 24 ... Rotor, 25 ... Rotating shaft, 26, 30 ... Bearing, 27, 31 ... Gear, 28 ... Crankshaft, 29 ... Connecting rod, 32 ... disc part, 33 ... pin, 34 ... cylinder holder, 35 ... cylinder, 36 ... retainer sleeve, 37 ... large diameter hole, 38 ... small diameter hole, 39 ... inclined surface, 40 ... front cover, 41 ... grip, 42 ... meson, 43 ... large diameter part, 44 ... piston, 45 ... striker, 46 ... O-ring, 47 ... first breathing hole, 48 ... second breathing hole, 49 ... damper holder 50 ... damper, 51 ... washer, 52, 53 ... stopper ring, 54 ... vibration reduction mechanism, 55 ... mass body, 56, 57 ... elastic member, 58, 59 ... groove, 60 ... contact portion, 61 ... snap ring, 62 ... Plate, 63, 65 ... Ring, 64 ... Stopper, A1 ... Center line, B1 ... Pressure chamber, C1 ... Space.

Claims (10)

A cylindrical support member for supporting a tip tool, a cylinder disposed concentrically with the support member, a piston disposed in the cylinder so as to be movable in a center line direction of the cylinder, and an interior of the cylinder A striking work that is arranged so as to be movable in the direction of the center line, and that strikes the tip tool, and a pressure chamber formed between the piston and the striking element inside the cylinder. Machine,
A first breathing hole that penetrates the cylinder in a radial direction and connects the inside and the outside of the cylinder;
A mass body arranged outside the cylinder and movable in the direction of the center line;
A contact portion provided on the mass body and in contact with an outer surface of the cylinder;
An elastic member disposed outside the cylinder and biasing the mass body in the direction of the center line;
Have
When the mass body is closest to the support member in the centerline direction, the location where the contact portion contacts the outer surface of the cylinder in the centerline direction is between the first breathing hole and the piston. There is a blow work machine. The cylinder has a second breathing hole that connects the inside and the outside of the cylinder,
The first breathing hole is disposed between the second breathing hole and the support member in the center line direction,
The striking work machine according to claim 1, wherein a portion where the contact portion contacts the outer surface of the cylinder in the center line direction is between the first breathing hole and the second breathing hole.   The striking work machine according to claim 1 or 2, wherein a total length of the mass body in the center line direction is larger than a total length of the contact portion in the center line direction.   The striking work machine according to claim 3, wherein when the mass body is closest to the support member in the center line direction, a part of the mass body overlaps the first breathing hole in the radial direction. The mass body includes notch portions arranged on both sides of the contact portion in the center line direction,
The striking work machine according to claim 1, wherein an inner diameter of the notch is larger than an inner diameter of the contact portion.   The impact work machine according to claim 1, wherein the elastic member is provided on both sides of the mass body in the center line direction.   The elastic member is a spring compressible in the center line direction, and the mass body is closest to the support member when the spring is in a fully compressed state. The hitting work machine described. A restricting member is provided for restricting the mass body from approaching the support member in the center line direction,
When the mass body is closest to the support member in the direction of the center line, the restricting member is configured such that the position where the contact portion contacts the outer surface of the cylinder is the first breathing hole and the position in the direction of the center line. The striking work machine according to any one of claims 1 to 7, wherein the striking work machine is between the piston.   The striking work machine according to claim 8, wherein the restriction member includes the elastic member.   The impact work machine according to claim 8, wherein the restriction member includes a stopper attached to an outer surface of the cylinder.

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