JP3815686B2 - Electric tool - Google Patents

Description

  The present invention relates to an electric power tool such as an impact driver or an oil pulse driver.

  A conventional power tool will be described with reference to FIG. FIG. 8 is a partially omitted vertical side view showing an impact tool for applying a rotational force and a striking force to the tip tool 20 such as a bit. In general, in a housing 1 or a case 10 that forms an impact tool body, a motor 2 that is a drive source, a speed reduction mechanism portion 8 that transmits rotational power of a pinion 4 that is an output shaft of the motor 2, and a speed reduction mechanism portion A spindle 14 that transmits rotational power from the spindle 8, a hammer 15 that is rotatable through a steel ball 16 inserted in a cam groove 14a formed in the spindle 14 and that is movable in the direction of the axis of rotation; An anvil 17 having an anvil claw 17b that is struck and rotated by a plurality of hammer claws 15b, a tip tool 20 that is attachable to and detachable from the anvil 17, and a spring 12 that constantly urges the hammer 15 toward the anvil 17 are housed. Yes. The speed reduction mechanism section includes a fixed gear support jig 7, a fixed gear 6, a planetary gear 8, and a spindle 14 that are supported by a rotation stopper in the housing 1, and are planets supported by the spindle 14. A needle pin 9 serving as a rotation shaft of the gear 8 is provided, and the gear 8 and the needle pin 9 form a part of the spindle 14.

  One end of the spindle 14 is pivotally supported by a bearing 11 and the other end is pivotally supported in a central hole 17a of an anvil 17 rotatably supported by a metal bearing 18.

  A pulse-like impact (impact) applied to a screw, nut, or the like that is tightened by the tip tool 20 supplies electric power to the motor 2 by operating the trigger switch 3 to rotate the motor, and then uses the rotational power of the motor 2 to rotate. The rotation is transmitted to the planetary gear 8 through the pinion 4 connected to the tip of the motor 2, and the rotational power of the pinion 4 is transmitted to the spindle 14 through the needle pin 9 by meshing with the planetary gear 8 and the fixed gear 6. The rotational force of the spindle 14 is transmitted to the hammer 15 via a steel ball 16 (steel ball) disposed between the cam groove 14a of the 14 and the cam groove 15a of the hammer 15, and the planetary gear 8 of the spindle 15 and the spindle 14 The hammer claw 15b of the hammer 15 urged forward (bit side) by the spring 12 disposed between It generated by striking the anvil claw 17b of Nbiru 17.

  After the impact, when the impact energy of the hammer 15 decreases and the torque of the anvil 17 decreases, the hammer 15 repels from the anvil 17, so the hammer 15 moves in the direction of the planetary gear 8 along the cam grooves 15 a and 14 a. Before the hammer 15 hits the stopper 22, the hammer 15 is pushed back along the cam grooves 15a and 14a again in the direction of the anvil 17 by the compression force of the spring 12, and further between the cam groove 14a of the spindle 14 and the cam groove 15a of the hammer 15. The hammer 15 is accelerated by the rotation of the spindle 14 through the steel balls 16 arranged on the surface. Since the spindle 14 continues to rotate while the hammer 15 reciprocates along the cam grooves 14a and 15a up to the stopper 22, the hammer pawl 15b of the hammer 15 gets over the anvil pawl 17b of the anvil 17, and the hammer pawl 15b again When hitting the anvil claw 17b, the anvil 17 is hit with the hammer 15 rotated 180 °. In this way, by repeatedly hitting the anvil 17 by the axial movement and rotation of the hammer 15, the screws and the like are tightened while continuously applying impact torque.

  As described above, the hammer's hammer claws and the anvil's anvil claws repeatedly collide with each other due to the rotation and axial movement of the hammer, thereby giving impact torque to the anvil. However, when a screw is tightened on hard wood or a bolt is tightened on an iron plate, the repulsive force from the anvil at the time of a collision is so great that the hammer has moved backward until it hits the stopper provided on the spindle. For this reason, every time the hammer hits the stopper, a force that instantaneously locks (presses) the rotating spindle acts. Therefore, even if the locking action is applied to the spindle, the pinion of the motor is rotating, so a large load (rotational impact force) is applied to the gear part of the reduction mechanism arranged between the motor and the spindle. There has been a problem that the speed reduction mechanism and the housing that holds the speed reduction mechanism are damaged.

  Further, since the locking action of the spindle works even when the hammer pawl and the anvil pawl collide, there has been a problem that the speed reduction mechanism and the housing holding the speed reduction mechanism are damaged.

  An object of the present invention is to provide a long-life power tool that can improve the durability by solving the above problems and buffering the rotational impact force of the speed reduction mechanism.

In order to achieve the above object, the present invention provides a motor as a drive source, a speed reduction mechanism, a striking mechanism that converts rotational power of the speed reduction mechanism into striking force, the motor, and the speed reduction mechanism. An electric power tool having a planetary gear to which the rotational power of the motor is transmitted and a fixed gear meshing with the planetary gear. A fixed gear supporting member that covers the surface is mounted on the housing, a first protrusion is provided on the fixed gear, and a second protrusion is provided at a position symmetrical to the first protrusion with respect to the center of the fixed gear. The fixed gear support member is provided with a hole portion into which the first protrusion and the second protrusion are inserted, and an impact cushioning material is interposed between each of the protrusions and the hole portion to thereby fix the fixed gear. The fixed gear support part And having one of the features that were over the impact cushioning material is secured to the housing.

  According to the present invention, the durability of the jig or housing supporting the speed reduction mechanism is improved by reducing the rotational impact force of the speed reduction mechanism against the sudden acceleration of the impact mechanism, and the tool life is improved. Can be increased. Moreover, since the load of each part is reduced, the material of each part can be changed to an inexpensive lower material. Further, by inserting the shock-absorbing material between the bearing of the impact mechanism part or the speed reduction mechanism part and the housing, it can be made smaller and more compact.

  Furthermore, by reducing the sudden rotational impact force, vibrations to the motor connected to the housing or the speed reduction mechanism are reduced, and workers with impact tools are lightly fatigued even when used for a long time. Improvement can be achieved and noise generated from vibration can be reduced.

  The impact tool in a present Example is demonstrated using FIGS. 1 and 2 show a first embodiment, FIG. 1 is a partially omitted vertical side view showing an impact tool, and FIG. 2 is an exploded view showing an impact relaxation mechanism mounted on the impact tool. 1 and 2, the impact tool is a deceleration that transmits the rotational power of a motor 2 as a drive source and a pinion 4 as an output shaft of the motor 2 in a housing 1 or a case 10 forming an impact tool body. A hammer that is rotatable and movable in the axial direction of the rotary shaft via a mechanism part 8, a spindle 14 that transmits rotational power from the speed reduction mechanism part 8, and a steel ball 16 inserted in a cam groove 14a formed in the spindle 14. 15, an anvil 17 having an anvil claw 17 b that is struck and rotated by a plurality of hammer claws 15 b provided on the hammer 15, a tip tool 20 that is detachable from the anvil 17, and the hammer 15 is always biased toward the anvil 17 side. The spring 12 is accommodated.

  The striking mechanism is mainly composed of a spring 12, a spindle 14, a hammer 15, a steel ball 16, and an anvil 17. The speed reduction mechanism section includes a fixed gear support jig 7, a fixed gear 6, a planetary gear 8, and a spindle 14 that are supported by a rotation stopper in the housing 1, and are planets supported by the spindle 14. A needle pin 9 serving as a rotation shaft of the gear 8 is provided, and the gear 8 and the needle pin 9 form a part of the spindle 14.

  One end of the spindle 14 is pivotally supported by a bearing 11 and the other end is pivotally supported in a central hole 17a of an anvil 17 rotatably supported by a metal bearing 18.

  A pulse-like impact (impact) applied to a screw, nut, or the like that is tightened by the tip tool 20 supplies electric power to the motor 2 by operating the trigger switch 3 to rotate the motor, and then uses the rotational power of the motor 2 to rotate. The rotation is transmitted to the planetary gear 8 through the pinion 4 connected to the tip of the motor 2, and the rotational power of the pinion 4 is transmitted to the spindle 14 through the needle pin 9 by meshing with the planetary gear 8 and the fixed gear 6. The rotational force of the spindle 14 is transmitted to the hammer 15 via a steel ball 16 (steel ball) disposed between the cam groove 14a of the 14 and the cam groove 15a of the hammer 15, and the planetary gear 8 of the spindle 15 and the spindle 14 The hammer claw 15b of the hammer 15 urged forward (bit side) by the spring 12 disposed between It generated by striking the anvil claw 17b of Nbiru 17.

  After the impact, when the impact energy of the hammer 15 decreases and the torque of the anvil 17 decreases, the hammer 15 repels from the anvil 17, so the hammer 15 moves in the direction of the planetary gear 8 along the cam grooves 15 a and 14 a. Before the hammer 15 hits the stopper 22, the hammer 15 is pushed back along the cam grooves 15a and 14a again in the direction of the anvil 17 by the compression force of the spring 12, and further between the cam groove 14a of the spindle 14 and the cam groove 15a of the hammer 15. The hammer 15 is accelerated by the rotation of the spindle 14 through the steel balls 16 arranged on the surface. Since the spindle 14 continues to rotate while the hammer 15 reciprocates along the cam grooves 14a and 15a up to the stopper 22, the hammer pawl 15b of the hammer 15 gets over the anvil pawl 17b of the anvil 17, and the hammer pawl 15b again When hitting the anvil claw 17b, the anvil 17 is hit with the hammer 15 rotated 180 °. In this way, by repeatedly hitting the anvil 17 by the axial movement and rotation of the hammer 15, the screws and the like are tightened while continuously applying impact torque.

  For the impact tool operating in this way, as shown in FIG. 2, the rotation direction of the rotation stopper 25 a is fixed in the housing 1, the outer peripheral portion is circular, and the fixed gear supporting jig whose center position is held with respect to the housing 1 is fixed. The fixed gear 6a engages with the tool 7a, the fixed gear 6a that holds the center position on the inner periphery of the fixed gear support jig 7a and is held so as to be minutely rotatable, and the protrusion 6b provided on the side surface of the fixed gear 6a. An impact mitigation mechanism comprising shock-absorbing materials 5a and 5b inserted into holes 7b provided in the support jig 7a is mounted.

  When the hammer 15 is moved in the direction of the planetary gear 8 along the cam grooves 15a and 14a by the impact relaxation mechanism and hits the stopper 22, the pinion 14 is always rotating, but the claw 6b of the fixed gear 6a Since the materials 5a and 5b are compressed, the rotational force in the rotational direction can be buffered by the minute rotation of the fixed gear 6a. Further, in this configuration, the shock absorbing members 5a and 5b are arranged in the gap between the bearing 11 which is the rear shaft support of the spindle 14 and the housing 1, so that the shock absorbing device is effectively provided without increasing the overall tool length. Can do. Further, since the shock absorbing materials 5a and 5b are arranged in the rotational load direction of the fixed gear 6a and on both sides of the projection 6b, it is possible to cope with forward / reverse rotation of the motor 2 and vibration of the load. Note that the number of the protrusions 6b is not limited to two as shown in the figure, and it is sufficient to have at least one protrusion.

  3 and 4 show a second embodiment, FIG. 3 is a partially omitted vertical side view showing an impact tool, and FIG. 4 is an exploded view showing an impact relaxation mechanism mounted on the impact tool. The impact tool shown in FIG. 3 has a protrusion 6d on the outer surface of the fixed gear 6c as shown in FIG. 4, and the fixed gear support jig 7c mounted on the housing 1 has a protrusion 6d on the outer surface of the fixed gear 6c. An impact mitigating mechanism having a hole 7d into which the shock absorbing materials 5c and 5d are inserted is mounted at a portion corresponding to the above.

  Since the fixed gear 6c is combined with the fixed gear support jig 7c so that the protrusion 6d of the fixed gear 6c is inserted between the shock buffers 5c and 5d by this shock relaxation mechanism, the shock relaxation mechanism shown in FIGS. Since the load is supported on the outer diameter side of the fixed gear 6c, the load can be buffered more effectively. However, the effect of the outer diameter of the fixed gear supporting jig 7c and the housing 1 becoming slightly larger can be sufficiently obtained.

  5 and 6 show a third embodiment, FIG. 5 is a partially omitted vertical side view showing an impact tool, and FIG. 6 is an exploded view showing an impact relaxation mechanism mounted on the impact tool. As shown in FIG. 6, the impact gear shown in FIG. 5 is fixed with a fixed gear 6 and a fixed gear support jig 7 e, and on both sides of a protrusion 7 f that is a rotation stop portion between the fixed gear support jig 7 e and the housing 1. An impact mitigating mechanism in which the shock absorbing materials 5e and 5f are arranged is mounted.

  By this shock relaxation mechanism, the side of the shock absorbing material 5e, 5f facing the projection 7f is pressed by the rib 1a of the housing 1 of the main body, and the shock absorbing materials 5e, 5f are interposed between the bearing 11 and the housing 1. Therefore, the rotational impact force can be buffered without increasing the overall length shape.

  FIG. 7 shows a fourth embodiment and is an external perspective view showing an impact relaxation mechanism mounted on an impact tool. As shown in FIG. 7, the fixed gear 6 and the fixed gear support jig 7g are fixed, and a projection 7h is provided on the outer surface of the fixed gear support jig 7g, and the rotation direction of the projection 7h and a rib (not shown) of the housing 1 are provided. An impact mitigation mechanism in which the shock absorbing materials 5g and 5h are arranged is mounted.

  Since this shock relaxation mechanism is a load support on the outer diameter side than the shock relaxation mechanism shown in FIG. 6, it can buffer the load more effectively than FIG. However, the effects of the outer diameter of the fixed gear supporting jig 7g and the main body housing 1 becoming large can be sufficiently obtained.

  By combining the above-described impact mitigation mechanism, the rotational shock between the fixed gear 6 and the housing 1 can be further reduced, and the shock absorbing material 5 to be used has various damping rubbers and soft plastics having a damping effect. It is desirable to use felt and the like.

It is a partially omitted vertical side view showing an impact tool according to the present invention. It is an exploded view which shows the 1st Example of the impact mitigation mechanism mounted in the impact tool of FIG. It is a partially omitted vertical side view showing an impact tool according to the present invention. FIG. 4 is an exploded view showing a second embodiment of the impact relaxation mechanism mounted on the impact tool of FIG. 3. It is a partially omitted vertical side view showing an impact tool according to the present invention. FIG. 6 is an exploded view showing a third embodiment of the impact relaxation mechanism mounted on the impact tool of FIG. 5. It is an external appearance perspective view which shows the 4th Example of the impact mitigation mechanism mounted in the impact tool which becomes this invention. It is a partially omitted vertical side view showing a conventional impact tool.

Explanation of symbols

1 is a housing, 2 is a motor, 5 is a shock absorbing material, 6a and 6c are fixed gears, 6b and 6d are protrusions, 7 is a fixed gear support jig, 9 is a planetary gear, 10 is a hammer case, 11 is a bearing, 14 Is a spindle, 15 is a hammer, 17 is an anvil, 20 is a cross screw driver bit, and 22 is a stopper.

Claims (1)

A motor as a drive source;
A deceleration mechanism,
A striking mechanism for converting the rotational power of the speed reduction mechanism to striking force;
A housing that houses the motor and the speed reduction mechanism;
In the electric tool having a planetary gear to which the rotational power of the motor is transmitted, and a fixed gear meshing with the planetary gear,
A fixed gear support member that covers the outer peripheral surface of the fixed gear with a circular outer peripheral portion is mounted on the housing, and
A first protrusion is provided on the fixed gear, a second protrusion is provided at a position symmetrical to the first protrusion with respect to the center of the fixed gear , and the first protrusion and the second protrusion are provided on the fixed gear support member. 2 is provided with a hole portion into which the projection is inserted, and an impact cushioning material is interposed between each projection and the hole portion to thereby fix the fixed gear to the housing via the fixed gear support member and the impact cushioning material. An electric tool characterized by being fixed to.

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