This application is the U.S. National Phase under 35 U.S.C. § 371 of International Application No. PCT/JP2020/009808, filed on Mar. 6, 2020, which claims the benefit of Japanese Application No. 2019-062892, filed on Mar. 28, 2019, the entire contents of each are hereby incorporated by reference.
The present invention relates to a driving work machine that performs a punching work or others to a workpiece by using a tip tool to apply a striking force to the workpiece.
Such a driving work machine is used to perform a punching work or others while using a tip tool to apply a striking force to a workpiece, and is also called hammer drill. The driving work machine has at least two work modes that are a drill mode that is a rotational mode and a rotational striking mode that is a hammer drill mode. In the drill mode, the machine performs the punching work by using the tip tool to transmit not the striking force but only the rotational force to the tip tool. In the hammer drill mode, the machine performs the punching work by applying the impact force to the workpiece while rotating the tip tool.
As described in a Patent Document 1, the driving work machine includes a striking element that is called a striker applying the striking force to the tip tool and a piston driving the striking element through a pneumatic pressure, and the striking element and the piston are embedded into a metallic cylinder. A second hammer that is an intermediate element that is driven by the striking element is embedded into the cylinder, and the striking force of the striking element is transmitted through the intermediate element to the tip tool attached to an end of the cylinder. The striking element, the intermediate element, the piston and the cylinder configure a striking mechanism. The cylinder is arranged in an inner case made of a metallic holder or case, and the inner case configures a part of a housing of the driving work machine.
Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2009-241195
At the time of the work using the driving work machine to apply the striking force to the workpiece, the striking element collides with a rear end surface of the intermediate element, so that the striking force is transmitted to the tip tool. The striking force applied from the tip tool to the workpiece is returned as a counteractive impact force from the workpiece to the intermediate element, and vibration applied to the tip tool is transmitted to the inner case. The inner case and the cylinder are embedded in a gear housing, the gear housing is connected to a motor housing, and the motor housing is provided with a handle.
Therefore, when the vibration applied to the tip tool is transmitted to the inner case, the vibration of the inner case is transmitted to the handle through the motor housing, and then, the vibration is applied to an operator's hand(s), and therefore, the workability is reduced.
A purpose of the present invention is to improve the workability of the driving work machine by reducing the vibration transmitted to the housing.
A driving work machine of the present invention includes: a cylinder configured to apply a rotational force to a tip tool; a piston attached to be able to reciprocate in an axis direction inside the cylinder and configured to apply a striking force to the tip tool; a driving source configured to generate a power for driving the cylinder and the piston; a switching part configured to make switching between at least two operational states including a rotational striking state of transmitting the power as a striking force and a rotational force to the tip tool and a rotational state of transmitting the power as the rotational force but not transmitting the power as the striking force to the tip tool; a housing configured to house the cylinder, the driving source and the switching part; and a spring member arranged between the housing and the switching part and configured to urge the switching part to move forward. The cylinder includes a pushing part pushing the switching part rearward when the cylinder is moved rearward by a reactive force of the pressing of the tip tool against a workpiece, the switching part is able to switch an operational state of the cylinder by using the rearward movement caused by the pushing force of the pushing part, the housing includes a preventing part configured to prevent an amount of the rearward movement of the switching part, and an anti-vibration part is arranged at least either between the pushing part and the switching part or between the switching part and the preventing part.
The cylinder that rotationally drives the tip tool is provided with the piston applying the striking force to the tip tool, and the striking force applied from the tip tool to the workpiece is returned as a counteractive force from the workpiece to the cylinder. However, since the anti-vibration part is arranged between the pushing part provided in the cylinder and the preventing part of the housing, the vibration and the impact force transmitted from the cylinder to the housing are reduced by the anti-vibration part. Since the vibration and the impact force transmitted to the housing are reduced, the workability of the driving work machine that is used when the operator performs the work while holding the handle can be improved.
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. As shown in
The gear housing 12a, the motor housing 12b and the handle part 12c configure a housing 12 of the driving work machine 10. When the gear housing 12a is assumed to be a front end of the driving work machine 10, the motor housing 12b is arranged at a rear end of the gear housing 12a. The handle part 12c that is arranged at a rear end of the motor housing 12b is almost at a right angle with respect to the motor housing 12b.
A sub handle 14 is attached to a front end of the gear housing 12a. The operator can perform such a work while holding the handle part 12c with his/her one hand and holding the sub handle 14 with the other hand, and also can perform such a work while holding only the handle part 12c.
A switch mechanism 15 is housed in the handle part 12c, and the switch mechanism 15 is connected to an external power supply by a power cable 16. When a trigger 17 connected to the switch mechanism 15 is operated, the power is supplied to the electric motor 13.
An inner case 18 is attached into the gear housing 12a. The inner case 18 has a radial-directional wall 18a fixed to the gear housing 12a and an axis-directional supporting part 18b protruding forward together with the radial-directional wall 18a. A cylinder 21 is attached to the axis-directional supporting part 18b of the inner case 18 to be movable and rotatable in the axis direction, and the cylinder 21 has a step form having a front end, a diameter of which is smaller than that of a rear end. The rear end of the cylinder 21 is supported by bearings 22 and 23, and the bearing 22 is attached to the inner case 18 while the bearing 23 is attached to a support ring 24 fixed to the gear housing 24. A sealing member 25 is mounted between the support ring 24 and the cylinder 21 so that entering of foreign substances such as dusts is suppressed.
A tool holding part 26 is attached to the front end of the cylinder 21, and the tool holding part 26 is mounted to the front end of the gear housing 12a to be movable. A rubber or a resin holding ring 27 is fitted with a gap between the tool holding part 26 and the front end of the cylinder 21, and a tip tool “T” is detachably mounted into a tool fitting part 20 arranged at the front end of the cylinder 21. A protrusion 28 that engages with a groove formed in the tip tool T to extend in the axis direction is arranged in the tool fitting part 20 of the cylinder 21. Further, a ball 29 that engages with a concave portion formed in the tip tool T is mounted to the cylinder 21. The ball 29 is stored in a storage groove 30 formed in the cylinder 21, and protrudes into the tool fitting part 20. An outside of the ball 29 is held by a ring 31, and a spring force in a direction heading to the tip tool T is applied to the ball 29 by a spring member 32. When the tip tool T is inserted into or detached from the front end of the cylinder 21, the spring force is applied as a damping force to the tip tool T.
A piston 33 is mounted into the rear end of the cylinder 21 to be able to reciprocate in the axis direction, and the piston 33 is provided with a capped cylindrical portion 34. A striker that is a striking element 35 is embedded into the cylindrical portion 34, and an air chamber 36 is made of the striking element 35 and the cylindrical portion 34. A second hammer that is an intermediate element 37 is fixed into the cylinder 21 by a fixing ring 38. A rear end of the intermediate element 37 is inserted into a concave portion 39 formed at a front end of the striking element 35. The cylinder 21, the piston 33, the striking element 35 and the intermediate element 37 configure the striking mechanism 11 for applying the rotational force and the striking force to the tip tool T.
As shown in
When the output shaft 42 is driven by the electric motor 13, the driving shaft 40 is driven to rotate around a rotational center axis O1, and the cylinder 21 is driven to rotate around a rotational center axis O2. In this manner, the rotational force is transmitted to the tip tool T. As described above, the driving shaft 40, the driving gear 44, the input gear 41 and the follower gear 45 configure a power transmitting part using the driving force of the electric motor 13 to transmit the rotational force to the cylinder 21, and the tip tool T is rotationally driven to rotate by the cylinder 21.
An axis-directional dimension of the driving gear 44 is longer than an axis-directional dimension of the follower gear 45 as shown in
A motion converting member 47 made of a spherical cam is mounted to the driving shaft 40 to be rotatable through a bearing, and a guide groove 48 that inclines to the rotational center axis O1 is formed in an outer circumferential surface of the motion converting member 47. A follower ring 49 is arranged outside the motion converting member 47, and a ball 52 is mounted to a gap between the guide groove 48 and a guide groove 51 that is formed in an inner circumferential surface of the follower ring 49. A driving rod 53 is fixed to the follower ring 49, and a rotational piece 54 that rotates around rotational center axis at a right angle with respect to a reciprocating direction of the piston 33 is attached to the piston 33. The driving rod 53 is fitted to be able to swing to a guide hole 55 that is arranged in the rotational piece 54 in a radial direction.
A cylindrically-shaped clutch 56 is mounted to the driving shaft 40 to be able to swing in the axis direction, and the clutch 56 rotates together with the driving shaft 40. A mesh part 57 is arranged in the clutch 56, and a mesh part 58 is arranged in the motion converting member 47 to correspond to this mesh part 57. In this manner, when the mesh part 57 and the mesh part 58 are meshed with each other by movement of the clutch 56 in the axis direction toward the motion converting member 47, the rotation of the driving shaft 40 is transmitted to the motion converting member 47 through the clutch 56. On the other hand, when the meshing is released, the transmission of the power to the motion converting member 47 is cut.
Therefore, when the driving shaft 40 is driven to rotate by the electric motor 13 to rotationally drive the motion converting member 47, the driving rod 53 swings around a center point “P” of the motion converting member 47, and the piston 33 is driven in the axis direction. In this manner, the rotational force of the driving shaft 40 is converted into the reciprocation force for the piston 33. When the piston 33 is driven toward a front side of the driving work machine 10, air in the air chamber 36 is compressed, and the striking element 35 is driven by the compressed air. When the striking element 35 is driven forward, the intermediate element 37 is driven by the striking element 35, and the impact force is applied to the tip tool T. Therefore, the driving shaft 40, the motion converting member 47 and the driving rod 53 configure a motion transmitting part that can transmit the forward striking force to the tip tool T by using the driving force of the electric motor 13.
Outside the rear end of the cylinder 21, a switching member 61 made of a thrust plate that is a plate member is mounted to be movable with respect to the cylinder 21 in the axis direction. As shown in
As shown in
In this case, the meshing part 57 of the clutch 56 is distant from the meshing part 58 of the motion converting member 47, and the rotational motion of the output shaft 42 of the electric motor 13 is not transmitted to the motion converting member 47 while the rotational motion is transmitted to only the cylinder 21 by the follower gear 45 meshing with the driving gear 44. Therefore, the driving work machine 10 is in the rotational state of rotationally driving the tip tool T. A rotational state of transmitting the rotational force but not transmitting the striking force to the tip tool is a rotational mode that is a drill mode.
On the other hand, when the meshing part 58 is meshed with the meshing part 57 by the pushing of the clutch 56 to the motion converting member 47, the rotational motion of the output shaft 42 is transmitted to the cylinder 21 and is also transmitted to the motion converting member 47. Because of the rotational driving of the motion converting member 47, the driving rod 53 swings around the swing center point P, and the piston 33 reciprocates in the axis direction. In this manner, the driving work machine 10 rotationally drives the tip tool T, and besides, is in a rotational striking state of applying the striking force. The rotational striking state of transmitting the rotational force and the striking force to the tip tool is a striking rotational mode that is a hammer drill mode.
Each of
A mode setting plate 67 is attached to the switch lever 66. As shown in
On the other hand, by the operation for the switch lever 66 to be in the hammer drill mode as shown in
A front end surface of the axis-directional supporting part 18b of the inner case 18 is a preventing part 71 on which the switching member 61 abuts, and the switching member 61 abuts on the preventing part 71 when the load heading rearward is applied to the cylinder 21. In this manner, an amount of the rearward movement of the switching member 61 is prevented when the switching member 61 abuts on the preventing part 71.
A rubber annular member 72 is arranged as an anti-vibration part in a gap between the pushing part 46 and the preventing part 71, the gap also being between the switching member 61 and the pushing part 46, and a thrust washer 73 is arranged between the annular member 72 and the switching member 61. In the arrangement of the rubber annular member 72 serving as the anti-vibration part between the pushing part 46 and the preventing part 71 that is the front end surface of the inner case 18 as described above, the impact vibration of the cylinder 21 is moderated by the annular member 72, and the switching member 61 is in contact with the preventing part 71 even when the switching member 61 made of the thrust plate collides with the preventing part 71 at the time of the reciprocation that is the vibration of the cylinder 21 in the axis direction as described in the hammer drill mode.
The cylinder 21 is a vibration generating source of the driving work machine 10 in the hammer drill mode. When the vibration generating source transmits the vibration to the inner case 18, the inner case 18 configuring a part of the housing 12 transmits the vibration to the handle part 12c and the sub handle 14. Therefore, the vibration is applied to an operator's hand (s) holding the handle part 12c, and therefore, the reduction in the workability cannot be avoided.
On the other hand, as shown in
Next, the punching work using the driving work machine 10 in the drill mode and the punching work using the same in the hammer drill mode of rotating the tip tool while using the tip tool to apply the impact force to the workpiece will be explained.
(Drill Mode)
When the driving work machine 10 is not driven while the switch lever 66 is operated to be in the driver mode as shown in
When the tip tool T is pressed against the workpiece in the state in which the drill mode is set as shown in
When the tip tool T is rotationally driven by the rotation of the cylinder 21 as described above, the punching work using the tip tool can be performed. At the time of this punching work, the vibration that is transmitted from the tip tool to the cylinder 21 is absorbed by the rubber annular member 72 arranged between the pushing part 46 and the switching member 61, and the vibration that is transmitted from the switching member 61 to the housing 12 through the return spring member 65 and the inner case 18 is damped. In this manner, the vibration that is transmitted to the operator's hand(s) holding the handle part 12c is reduced, so that the workability of the driving work machine 10 can be improved.
(Hammer Drill Mode)
On the other hand, in the work in the hammer drill mode, the switch lever 66 is operated to be at the position of the hammer drill mode by the operator as shown in
Therefore, when the cylinder 21 is moved rearward by the pressing of the tip tool T against the workpiece, the engagement avoiding groove 69 of the switching member 61 passes outside the engaging protrusion 68. In this manner, as shown in
The driving rod 53 is swung around the center point P by the rotation of the motion converting member 47, and the piston 33 is reciprocated in the axis direction by the swinging motion of the driving rod 53. In the reciprocation of the piston 33, the striking element 35 is driven to protrude forward by the compressed air inside the air chamber 36, and collides with the intermediate element 37. In this manner, the striking force is applied to the tip tool T. The cylinder 21 is rotationally driven by the driving shaft 40, the striking force and the rotational force are applied to the tip tool T, and the punching work is performed at the same time as the application of the striking force to the workpiece by the tip tool T.
In such a hammer drill mode, the striking force that has been applied from the tip tool T to the workpiece returns as a counteraction from the workpiece to the intermediate element 37, and is transmitted to the cylinder 21, and the cylinder 21 becomes the vibration generating source. Since the rubber annular member 72 that is the anti-vibration part is arranged between the pushing part 46 of the cylinder 21 and the switching member 61, the impact force and the vibration applied to the cylinder are absorbed by the rubber annular member 72 arranged between the pushing part 46 and the switching member 61, so that the impact force and the vibration transmitted from the switching member 61 to the housing 12 through the inner case 18 are damped. In this manner, the impact force and the vibration transmitted to the operator's hand(s) holding the handle part 12c are reduced, so that the workability of the driving work machine 10 can be improved.
Each of
In a driving work machine 10 shown in
Even when the annular member 72 has the fitting hole while the pushing part 46 has the fitting protrusion, the durability of the annular member can be similarly improved by the prevention of the movement of the annular member 72 with respect to to the cylinder 21.
In place of the annular member 72, a driving work machine 10 shown in
In a driving work machine 10 shown in
In a driving work machine 10 shown in
The present invention is not limited to the foregoing embodiments, and various modifications can be made within the scope of the present invention. For example, the driving work machine 10 of the embodiments can be switched between the two operational states that are the drill mode and the hammer drill mode. However, the present invention is also applicable to the driving work machine having the hammer mode as described in the Patent Document 1 in addition to these modes. In other words, the present invention is applicable to the driving work machine at least having the two modes that are the drill mode and the hammer drill mode.
10 . . . driving work machine, 11 . . . striking mechanism, 12 . . . housing, 12a . . . gear housing, 12b . . . motor housing, 12c . . . handle part, 13 . . . electric motor (driving source), 18 . . . inner case, 20 . . . tool fitting part, 21 . . . cylinder, 26 . . . tool holding part, 27 . . . holding ring, 32 . . . spring member, 34 . . . cylindrical part, 35 . . . striking element, 36 . . . air chamber, 37 . . . intermediate element, 40 . . . driving shaft, 46 . . . pushing part, 47 . . . motion converting member, 49 . . . follower ring, 52 . . . ball, 53 . . . driving rod, 54 . . . rotational piece, 56 . . . clutch, 61 . . . switching member, 62 . . . fitting hole, 63 . . . annular groove, 64 . . . engaging part, 65 . . . return spring member, 66 . . . switch lever, 67 . . . mode setting plate, 68 . . . engaging protrusion, 69 . . . engagement avoiding groove, 71 . . . preventing part, 72 . . . annular member, 73 . . . thrust washer, 74 . . . fitting hole, 75 . . . fitting protrusion, 76 . . . compression coil spring, 77 . . . wave washer
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2019-062892 | Mar 2019 | JP | national |
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WO2020/195725 | 10/1/2020 | WO | A |
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