JP6455227B2 - Impact tool - Google Patents

Description

  The present invention relates to an impact tool that transmits power of a power source to a tip tool holding portion.

  2. Description of the Related Art Conventionally, hitting tools that transmit power from a power source to a tip tool holding unit are known, and an example of the hitting tool is described in Patent Document 1. The impact tool described in Patent Document 1 is an impact driver, and the impact driver has an impact tool main body (housing) as a first case and a hammer case as a second case. An electric motor having an output shaft and a speed reducer to which the rotational force of the output shaft is transmitted are housed in the housing. The reduction gear is constituted by a planetary gear, and is connected to an input shaft of the planetary gear mechanism, and a spindle is connected to an output shaft of the planetary gear mechanism.

  The hammer case is attached to the open end of the housing, and supports the anvil that transmits the rotational force output from the spindle to the hammer case, the anvil that transmits the rotational force of the hammer and serves as a tip tool holding portion, and the anvil. Contains metal bearings. A part of the anvil is disposed outside the hammer case, and a tip tool is attached to the anvil. Further, a support hole is provided in the anvil, and an end portion of the spindle is inserted into the support hole so that the spindle is rotatably supported. And the grease is hold | maintained in the support hole. A cylindrical metal bearing is provided in the hammer case, and the anvil is rotatably supported by the metal bearing.

  In the impact driver described in Patent Document 1, the rotational force of the electric motor is transmitted to the anvil via the speed reducer, the spindle, and the hammer, and a fastening member such as a screw is tightened by a tip tool attached to the anvil. When the screw tightening load increases, the hammer moves in a direction away from the anvil, and the hammer rotates within a predetermined angle range with respect to the anvil. When the hammer's claws get over the anvil's claws, the hammer moves in a direction approaching the anvil, and a hammering force in the rotational direction is applied from the hammer to the anvil.

JP 2004-174656 A

  In the striking tool described in Patent Document 1, when the hammer strikes the anvil, the hammer is tilted by impact due to the striking, and a force is generated in the anvil so as to tilt with respect to the output shaft.

  Therefore, the anvil also rotates in a tilted state by the hammer tilted at the time of striking. When the anvil is rotated in a tilted state, the surface pressure between the anvil and the metal bearing becomes higher than usual, which may cause galling.

  The objective of this invention is providing the impact tool which suppresses the inclination of the hammer at the time of impact.

  The present invention includes a tip tool holding portion that holds a tip tool, and a first protrusion that is provided on the rear side of the tip tool holding portion and projects toward the tip tool holding portion and strikes the tip tool holding portion. A hammering tool comprising a hammer and a hammer case for accommodating the hammer so as to be reciprocally movable, wherein the hammer has a second projecting portion projecting forward from the first projecting portion, and the hammer In the reciprocating direction, the second projecting portion overlaps the tip tool holding portion.

  According to the present invention, it is possible to suppress the inclination of the hammer at the time of hitting.

It is a fragmentary sectional view of the impact tool used as an embodiment of the invention. It is a figure which shows the hammer of the impact tool used as embodiment of this invention, (a) is a front view, (b) is AA sectional drawing of (a). It is a fragmentary sectional view of an impact tool used as another embodiment of the present invention.

  Embodiments of the present invention will be described in detail with reference to the drawings. The impact tool 10 shown in FIG. 1 is an impact driver used for tightening or loosening screws. The striking tool 10 has a hollow tool body 11. The tool body 11 includes a housing 12 and a hammer case 13 fixed to an opening end on the front side of the housing 12 in the front-rear direction (left-right direction in the figure). An electric motor 14 serving as a drive source is provided in the internal space A of the housing 12, and a rotating shaft 15 of the electric motor 14 extends in the front-rear direction and is rotatably supported by two bearings 16 and 17. The rotation direction of the rotating shaft 15 of the electric motor 14 can be switched by operating a forward / reverse selector switch (not shown). In FIG. 1, the side where the hammer case 13 is located with respect to the housing 12 is the front side, and the opposite side is the rear side.

  A partition wall 18 that partitions the internal space A of the housing 12 and the internal space B of the hammer case 13 is provided. The partition wall 18 is formed in an annular shape, and a bearing 17 is disposed between the inner peripheral surface of the partition wall 18 and the outer peripheral surface of the rotary shaft 15. A bearing 16 is disposed between the housing 12 and the rotating shaft 15. The rotation shaft 15 rotates about the center line C.

  The hammer case 13 has a shaft hole 19, and a metal bearing 20 (metal) serving as a support portion that rotatably supports the anvil 23 is attached to the shaft hole 19. The metal 20 is pressed into the shaft hole 19 of the hammer case 13 and fixed. The metal 20 includes a support portion 20a that supports the outer peripheral portion of the anvil 23, and a flange 21 that is provided continuously at the end of the support portion 20a and projects outward in the radial direction. An elastic body 22, for example, resin is integrally formed on the outer periphery of the flange 21 over the entire outer periphery of the flange 21. An anvil 23 as a tip tool holding portion is rotatably disposed inside the metal 20. The anvil 23 can rotate around the center line C. The anvil 23 is provided from the internal space B of the hammer case 13 to the outside of the tool body 11 (hammer case 13), and a tool holding hole 24 centered on the center line C of the anvil 23 is provided. ing. The tool holding hole 24 is opened to the outside of the tool body 11, and a tip tool 54 such as a bit is attached to and detached from the tool holding hole 24.

  The anvil 23 is provided with a support hole 23 a concentric with the tool holding hole 24. The support hole 23 a is opened toward the internal space B of the hammer case 13. The support hole 23 a is not connected to the tool holding hole 24. Furthermore, two protrusions 25 (anvil claw portions) are provided on the outer peripheral surface of the anvil 23 at locations arranged in the internal space B of the hammer case 13. The two protrusions 25 are arranged at intervals of 180 degrees in the circumferential direction of the anvil 23.

  On the other hand, a reduction gear 26 is provided in the internal space B of the hammer case 13. The reduction gear 26 is disposed between the bearing 17 and the anvil 23 in a direction along the center line C. The reduction gear 26 is a power transmission device that transmits the rotational force, that is, torque, of the electric motor 14 to the anvil 23, and the reduction gear 26 is configured by a single pinion type planetary gear mechanism.

  The reduction gear 26 includes a sun gear 27 disposed concentrically with the rotary shaft 15, a ring gear 28 provided so as to surround the outer peripheral side of the sun gear 27, a plurality of pinion gears 29 engaged with the sun gear 27 and the ring gear 28, and a plurality of gears. And a carrier 30 that supports the pinion gear 29 so as to be capable of rotating and revolving. The sun gear 27 is formed on the outer peripheral surface of the intermediate shaft 31 attached to one end side of the rotary shaft 15, and the intermediate shaft 31 rotates integrally with the rotary shaft 15. The ring gear 28 is fixed to the partition wall 18. Furthermore, in order to seal between the outer peripheral surface of the ring gear 28 and the inner peripheral surface of the hammer case 13, an O-ring 32 serving as a sealing device is interposed therebetween.

  The carrier 30 includes a pinion pin 33 to which the pinion gear 29 is attached, and a first component piece 34 and a second component piece 35 respectively connected to both ends of the pinion pin 33 in the longitudinal direction. The first component piece 34 has an annular shape, and a part of the intermediate shaft 31 is disposed inside the first component piece 34. A bearing 36 is provided between the partition wall 18 and the first component piece 34, and the first component piece 34 is rotatably supported by the bearing 36.

  The second component piece 35 is disposed between the anvil 23 and the first component piece 34 in the direction along the center line C. A spindle 37 that rotates together with the carrier 30 around the center line C is provided. The spindle 37 is disposed between the anvil 23 and the bearing 36 in the direction along the center line C, and the second component piece 35 is continuously provided at the end of the spindle 37 near the bearing 36. It has been. That is, the second component piece 35 is an outward flange formed on the outer peripheral surface of the spindle 37.

  An annular plate 38 that surrounds the spindle 37 is provided. Further, a stopper 39 is provided on the outer periphery of the spindle 37 and inside the plate 38. The stopper 39 is a damper that absorbs or relaxes an impact force, and is a rubber-like elastic body.

  On the other hand, a shaft portion 40 protruding in the direction along the center line C is formed at the end portion of the spindle 37 on the anvil 23 side. The shaft portion 40 is disposed in the support hole 23 a, and the spindle 37 is rotatably supported by the metal 20 through the anvil 23. A substantially V-shaped cam groove 41 is provided on the outer peripheral surface of the spindle 37 between the shaft portion 40 and the stopper 39.

  A hammer 42 is accommodated in the internal space B of the hammer case 13, and the hammer 42 is provided so as to surround the spindle 37. The hammer 42 has a substantially annular shape and a substantially cylindrical shape. The hammer 42 is disposed between the speed reducer 26 and the anvil 23 in the direction along the center line C. The hammer 42 can rotate relative to the spindle 37 and can move relative to the spindle 37 in a direction along the center line C. That is, the hammer 42 can reciprocate in the front-rear direction along the center line C, in other words, can reciprocate.

  The hammer 42 has an outer cylinder part 43 and an inner cylinder part 44, and the outer cylinder part 43 is arranged outside the inner cylinder part 44. A cam groove 45 is formed on the inner peripheral surface of the inner cylinder portion 44. The rear end face of the inner cylinder portion 44 and the rear end face of the outer cylinder portion 43 are at the same position in the direction along the center line C.

  A steel ball (steel ball) 46 is held by the cam groove 41 of the spindle 37 and the cam groove 45 of the hammer 42. For this reason, the hammer 42 is movable in the front-rear direction along the center line C within a range in which the steel ball 46 can roll with respect to the spindle 37. Further, the hammer 42 is movable in the circumferential direction (rotating direction) about the center line C within a range in which the steel ball 46 can roll with respect to the spindle 37.

  Further, the hammer 42 has a holding groove 47 formed between the outer cylinder portion 43 and the inner cylinder portion 44. The holding groove 47 is opened toward the speed reducer 26. The holding groove 47 is provided in an annular shape around the center line C. A steel ball 48 is provided at the bottom of the holding groove 47. A plurality of steel balls 48 are arranged in the circumferential direction so as to fill the bottom of the holding groove 47. An annular plate 49 is provided at a location closer to the plate 38 than the steel ball 48 in the holding groove 47.

  Further, a compression spring 50 is interposed between the plate 38 and the plate 49 in the direction along the center line C. A part of the compression spring 50 is disposed in the holding groove 47, and the pressing force of the compression spring 50 is applied to the hammer 42 via the plate 49 and the steel ball 48. That is, the hammer 42 is pressed toward the anvil 23 in the direction along the center line C by the pressing force of the compression spring 50.

  A projecting portion 51 (hammer claw portion) serving as a first projecting portion projecting in a direction along the center line C is provided on the anvil 23 side of the hammer 42. Two protrusions 51 are provided at intervals of 180 degrees in the circumferential direction of the hammer 42. The protrusion 51 of the hammer 42 and the protrusion 25 of the anvil 23 are arranged on the same circumference around the center line C. When the hammer 42 moves in the direction along the center line C, the protrusion 51 and the protrusion 25 is engaged or released.

  Further, an annular projecting portion 52 serving as a second projecting portion projecting in the direction along the center line C is provided on the end portion on the anvil 23 side of the hammer 42 over the entire circumference. The inner peripheral surface of the annular protrusion 52 of the hammer 42 overlaps the outer peripheral surface of the flange 21 of the metal 20 in the direction along the center line C. The annular projecting portion 52 projects further to the anvil 23 side than the projecting portion 51 (hammer claw portion).

  Next, the operation of the impact driver 10 serving as an impact tool will be described. In a state where the electric motor 14 is stopped, the hammer 42 pressed by the compression spring 50 is in contact with the anvil 23 and stopped. When electric power is supplied to the electric motor 14 from a power source (not shown) (battery pack or commercial power supply) and the rotary shaft 15 rotates, the torque of the rotary shaft 15, that is, the rotational force, is transmitted to the sun gear 27 of the speed reducer 26. When the rotational force is transmitted to the sun gear 27, the ring gear 28 becomes a reaction force element, and the carrier 30 becomes an output element. That is, when the rotational force of the sun gear 27 is transmitted to the carrier 30, the rotational force of the ring gear 30 is reduced with respect to the rotational speed of the sun gear 27, thereby amplifying the rotational force.

  When the rotational force is transmitted to the carrier 30, the spindle 37 rotates together with the carrier 30. The rotational force of the spindle 37 is transmitted to the hammer 42 through the steel ball 46. The rotational force of the hammer 42 is transmitted to the anvil 23 by the engaging force between the protrusion 51 of the hammer 42 and the protrusion 25 of the anvil 23, and the anvil 23 rotates. The rotational force of the anvil 23 is transmitted to the screw through the tip tool 54, and the screw is screwed into an object, for example, wood.

  Thereafter, when the screw is screwed into the wood, the frictional resistance between the wood and the screw increases, and the torque necessary to rotate the tip tool 54 increases, the rotation of the anvil 23 stops, and the anvil 23 and the hammer 42 And relative rotation. Then, the hammer 42 moves in a direction away from the anvil 23 due to the reaction force generated at the contact surface between the steel ball 46 and the cam groove 45. The movement of the hammer 42 in a direction away from the anvil 23 is called retreat.

  The hammer 42 moves rearward along the center line C against the pressing force of the compression spring 50. Then, the steel ball 46 moves in a direction approaching the end of the cam groove 41, the engagement between the protrusion 51 and the protrusion 25 is released, and the rotational force of the hammer 42 is not transmitted to the anvil 23.

  Further, the end portion of the hammer 42 in the reciprocating direction, that is, the end portion of the inner cylinder portion 44 collides with the stopper 39, and the steel ball 46 reaches the end portion of the cam groove 41. When the end of the inner cylinder 44 collides with the stopper 39, the stopper 39 is elastically deformed, and the stopper 39 absorbs kinetic energy when the hammer 42 moves away from the anvil 23. The stopper 39 restricts a range in which the hammer 42 operates in a direction away from the anvil 23 along the center line C.

  Further, when the rotation of the hammer 42 is continued and the protruding portion 51 gets over the protruding portion 25, the pressing force applied to the hammer 42 by the compression spring 50 is higher than the force in the direction of moving the hammer 42 away from the anvil 23. Become. Then, the steel ball 46 rolls along the cam grooves 41 and 45, whereby the hammer 42 and the spindle 37 rotate relative to each other, and the hammer 42 moves along the center line C in a direction approaching the anvil 23. . The movement of the hammer 42 in the direction approaching the anvil 23 is called forward movement.

  Thereafter, the projecting portion 51 of the rotating hammer 42 collides with the projecting portion 25 of the stopped anvil 23, and a striking force in the rotational direction is applied to the anvil 23. It should be noted that the screw can be loosened by reversing the direction of rotation of the rotating shaft 15 of the electric motor 14 in contrast to when the screw is tightened.

  Here, the structure for suppressing galling between the anvil 23 and the metal 20 according to the present embodiment will be described. In the direction along the center line C, the region where the hammer 42 is supported by the spindle 37 is short (small). Therefore, the hammer 42 is easy to tilt in the direction intersecting the center line C with respect to the spindle 37. When the anvil 23 is hit with the hammer 42 tilted, the anvil 23 tilts with respect to the metal 20 and galling occurs.

  Therefore, according to the present embodiment, even when the hammer 42 is tilted with respect to the spindle 37, the hammer 42 is configured to suppress the tilt. Specifically, as described above, an annular projecting portion 52 projecting toward the anvil 23 side along the center line C is provided at the end portion of the hammer 42 on the anvil 23 side over the entire circumference. Further, the annular protrusion 52 overlaps the flange 21 of the metal 20 in the direction along the center line C.

  With this configuration, when the hammer 42 is inclined with respect to the spindle 37, the inner peripheral surface of the annular protrusion 52 abuts on the outer peripheral surface of the flange 21. Since the metal 20 is press-fitted into the shaft hole 19 of the hammer case 13, the metal 20 does not tilt with respect to the hammer case 13. That is, even if the hammer 42 (annular protrusion 52) contacts the flange 21 of the metal 20, the flange 21 does not tilt with respect to the hammer case 13, so that the flange 21 serves as a stopper and prevents the hammer 42 from tilting further. can do.

  Therefore, even when the hammer 42 and the metal 20 (flange 21) are engaged (contacted) immediately before the hammering during the forward movement of the hammer 42 during the screw tightening operation, the inclination of the hammer 42 due to the impact of the hammering is suppressed. Can do. Thereby, only the force in the rotational direction, that is, the torque is transmitted to the anvil 23. As a result, since the tilting force does not act on the anvil 23, it becomes possible to suppress the galling that has occurred in the anvil 23 and the metal 20.

  Further, by providing the elastic body 22 on the outer peripheral surface of the flange 21, it is possible to reduce vibration and noise generated when the hammer 42 is inclined and abuts on the flange 21, and the force applied to the flange 21.

  Next, the structure which suppresses the inclination of the hammer 42 in 2nd Embodiment is demonstrated using FIG. An elastic body 53 such as a resin is integrally formed on the inner peripheral surface of the hammer case 13. The elastic body 53 is provided so as to overlap with the annular protrusion 52 in the direction along the center line C. In the impact tool 10 of the present embodiment, the hammer 42 and the elastic body 53 on the inner peripheral surface of the hammer case 13 can be engaged (contacted) only immediately before impact during the forward movement of the hammer 42 during the screw tightening operation. It has become. With this configuration, as in the first embodiment, it is possible to suppress the inclination of the hammer 42 due to impact of impact. That is, the inclination of the anvil 23 due to the inclination of the hammer 42 can be reduced, and it is possible to suppress galling that has occurred in the anvil 23 and the metal 20. Also with this configuration, it is possible to reduce the vibration and noise generated when the hammer 42 is tilted and comes into contact with the flange 21 and the force applied to the flange 21.

  While the present invention has been described based on the embodiments, it is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, the configuration in which the elastic body 22 is provided on the flange 21 shown in FIG. 1 and the configuration in which the elastic body 53 is provided on the hammer case 13 shown in FIG. 3 can be combined. In addition, the annular protrusion 52 is formed in an annular shape (cylindrical shape) over the entire periphery, but the protrusions 52 may be provided at a plurality of locations on the entire periphery. That is, any shape that can contact the flange 21 when the hammer 42 is tilted may be used. In the second embodiment, the elastic body 53 may be provided so as to be in contact with the rear end portion of the hammer 42.

  In the above-described embodiment, the tip tool is directly attached to the anvil. However, the tip tool may be indirectly attached to the anvil via an adapter or an extension bar. Further, although the center line of the rotating shaft of the electric motor coincides with the center line in which the hammer reciprocates, the center line may be configured to be substantially parallel or intersect. Furthermore, the present invention can be applied to any configuration that hits an anvil with a hammer, such as an impact wrench.

  10 is an impact tool (impact driver), 11 is a tool body, 12 is a housing, 13 is a hammer case, 14 is an electric motor, 15 is a rotary shaft, 16 is a bearing, 17 is a bearing, 18 is a partition, 19 is a shaft hole , 20 is a metal, 20a is a support portion, 21 is a flange, 22 is an elastic body, 23 is an anvil, 23a is a support hole, 24 is a tool holding hole, 25 is a protrusion, 26 is a reduction gear, 27 is a sun gear, and 28 is Ring gear, 29 is a pinion gear, 30 is a carrier, 31 is an intermediate shaft, 32 is an O-ring, 33 is a pinion pin, 34 is a first component piece, 35 is a second component piece, 36 is a bearing, 37 is a spindle, and 38 is a plate , 39 is a stopper, 40 is a shaft, 41 is a cam groove, 42 is a hammer, 43 is an outer cylinder, 44 is an inner cylinder, 45 is a cam groove, 46 is a steel ball, 47 is a holding groove, and 48 is a steel ball. , 9 the plate, the compression spring 50, 51 protrusion, 52 annular protrusion, 53 the elastic body 54 is tool bit.

Claims (7)

A tip tool holding portion for holding the tip tool;
A hammer provided on the rear side of the tip tool holding portion, and having a first projecting portion that projects toward the tip tool holding portion and strikes the tip tool holding portion;
A hammer case for accommodating the hammer in a reciprocating manner;
A bearing portion supported by the hammer case and rotatably supporting the tip tool holding portion;
A striking tool comprising
The hammer has a second projecting portion projecting forward from the first projecting portion,
In the reciprocating direction of the hammer, the second projecting portion overlaps the bearing portion. The bearing portion includes a support portion that supports the tip tool holding portion, and a flange portion that projects from the support portion to the radially outer side of the tip tool holding portion,
The impact tool according to claim 1, wherein the second projecting portion overlaps the flange portion in a reciprocating direction of the hammer.   The impact tool according to claim 2, wherein an inner peripheral portion of the second projecting portion can contact an outer periphery of the flange portion.   The impact tool according to claim 2, wherein an elastic body is provided on an outer peripheral surface of the flange portion.   The striking tool according to claim 1, wherein an elastic body capable of contacting the second projecting portion is provided on an inner peripheral surface of the hammer case. A tip tool holding portion for holding the tip tool;
A hammer provided on the rear side of the tip tool holding portion, and having a first projecting portion that projects toward the tip tool holding portion and strikes the tip tool holding portion;
A hammer case for accommodating the hammer in a reciprocating manner;
A bearing portion supported by the hammer case and rotatably supporting the tip tool holding portion;
A striking tool comprising
Inside the hammer case is provided an elastic body that contacts the hammer when the hammer is tilted in a direction intersecting the reciprocating direction of the hammer,
The hammer has a second projecting portion projecting forward from the first projecting portion,
The bearing portion includes a support portion that supports the tip tool holding portion, and a flange portion that projects from the support portion to the radially outer side of the tip tool holding portion,
In the reciprocating direction of the hammer, the second projecting portion overlaps with the flange portion, and the elastic body is provided on an outer periphery of the flange portion and can contact the second projecting portion. Blow tool. A tip tool holding portion for holding the tip tool;
A hammer provided on the rear side of the tip tool holding portion, and having a first projecting portion that projects toward the tip tool holding portion and strikes the tip tool holding portion;
A hammer case for accommodating the hammer in a reciprocating manner;
A bearing portion supported by the hammer case and rotatably supporting the tip tool holding portion;
A striking tool comprising
Inside the hammer case is provided an elastic body that contacts the hammer when the hammer is tilted in a direction intersecting the reciprocating direction of the hammer,
The hammer has a second projecting portion projecting forward from the first projecting portion,
The impact tool according to claim 1, wherein the elastic body is provided on an inner peripheral surface of the hammer case so that the second projecting portion can come into contact therewith.