JP2004249422A - Rotary hammer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary hammer provided with durability with a socket by relieving a speed for a hammer to impact an anvil when tightening a bolt in the rotary hammer having a rotary impact generating mechanism part and a speed reduction mechanism part for tightening a screw and the bolt. <P>SOLUTION: This rotary hammer has the hammer movable in the shaft direction to a rotatably driven spindle and a hammer claw to which torque is transmitted from the spindle, and the anvil having an anvil claw to which rotary impact force is applied by the hammer claw, and is characterized by applying a nonslip member to a head part of the anvil claw and a head part of the hammer claw. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary impact tool that includes a rotary impact generating mechanism that is rotationally driven by a motor such as electricity or air to generate an impact force, and a deceleration mechanism, and fastens a screw or a bolt.
[0002]
[Prior art]
Conventionally, general rotary impact tools include a hammer and anvil, which are rotary impact mechanisms, a spindle, a planetary gear, and a ring-shaped fixed gear and a pinion which are fixed to a housing as a reduction mechanism, and a drive unit. There are tools with motors.
[0003]
FIG. 1 illustrates a conventional rotary hitting mechanism of a rotary hitting tool.
[0004]
An electric motor 2 fixed in a housing 1, a fixed gear supporting jig 7, a fixed gear 6, a planetary gear 8, and a spindle 14, which are supported with a detent in the housing 1, are arranged in a hammer case 10. The hammer 15 and the anvil 17 are arranged, the spring 12 is arranged between the planetary gear 8 side of the spindle 14 and the hammer 15, and the anvil 17 is a tightening tool such as a cross screwdriver bit 20 or a hexagon bolt socket 23 shown in FIG. Attached tip tool can be connected.
[0005]
The reduction mechanism includes a pinion 4 attached to the motor 2, a fixed gear 6, a planetary gear 8, and a needle pin 9 supported on a spindle 14 by a rotation shaft of the planetary gear 8. Is a part of the spindle 14. The spindle 14 is rotatably supported at its rear end by a bearing 11 and at its front end by a center hole 17 a of an anvil 17 supported by a bearing 18.
[0006]
The operation of generating a pulsed rotary impact torque applied to the anvil 17 is performed when the motor 2 supplied with power is turned on when the switch 3 is turned on, and the power of the motor 2 is transmitted via the pinion 4 connected to the tip of the motor 2. And transmitted to the planetary gear 8. Since the planetary gear 8 meshes with the fixed gear 6, the power of the pinion 4 drives the spindle 14 to rotate via the needle pin 9, and rotates the ball 16 disposed between the cam groove 14 a of the spindle 14 and the cam groove 15 a of the hammer 15. Via this, the rotation of the spindle 14 is transmitted to the hammer 15. The hammer 15 is urged forward by a spring 12 disposed between the hammer 15 and the planetary gear 8 of the spindle 14, and is pushed forward along the cam grooves 14a, 15a. Thereafter, the hammer claw 15b of the hammer 15 having energy due to the spring force, the rotation speed, and the moment of inertia hits the anvil claw 17b of the anvil 17 so that the anvil 17 rotates and the bit 20 or the socket connected to the anvil 17 is driven. A torque is applied to the screw 24 shown in FIG. 3 or the bolt 25 shown in FIG.
[0007]
Thereafter, 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, and the hammer 15 moves toward the planetary gear 8 along the cam grooves 15a and 14a. Thereafter, the hammer 15 is pushed back along the cam grooves 15a, 14a again in the direction of the anvil 17 by the compressive force of the spring 12, and further through the ball 16 arranged between the cam groove 14a of the spindle and the cam groove 15a of the hammer. By the rotation of 14, the hammer 15 is accelerated. Since the spindle 14 continues to rotate while the hammer 15 reciprocates along the cam grooves 14a, 15a up to the stopper 22, the claw 15b of the hammer 15 climbs over the claw 17b of the anvil 17, and again the hammer claw 15b Strikes the anvil 17 with the hammer 15 rotated about 180 °. By repeatedly hitting the anvil 17 by the axial movement and rotation of the hammer 15, pulse-like impact torque is continuously generated, and the screw 24 or the bolt 25 is tightened.
[0008]
FIG. 7 shows the head 15c of the hammer claw 15b of the hammer 15 and the head 17c of the spindle claw 17b of the spindle 17. Both the hammer claw head 15c and the spindle claw head 17c are flat and have a forged skin or When the hammer claw head 15c is in contact with the spindle claw head 17c, the hammer claw 15b hits the spindle claw 17b without substantially reducing the rotation speed of the hammer.
[0009]
[Problems to be solved by the invention]
In the conventional rotary impact tool, when the screw 24 is tightened to wood or the like, the hammer 15 hits the anvil 17, and the rotation energy of the hammer 15 causes the anvil 17 to rotate. Tighten. Thereafter, the hammer 15 repels from the anvil 17 and the hammer 15 moves in the direction of the planetary gear 8 along the cam grooves 15a and 14a. However, since most of the energy of the hammer 15 is used for screw tightening, the rebound is small.
[0010]
Referring to FIG. 5, the operation of the hammer 15 in the case of screw tightening will be described. After the hammer 15 rotates down along the cam groove and the hammer claw 15b hits the anvil claw 17b (A1 in the figure), the hammer 15 repels. However, the hammer claw 15b strikes the anvil 17b again without reaching the stopper 22 (A2 in the figure) (B2 in the figure).
[0011]
The operation of the above-described hammer 15 is typically repeated in screw tightening.
[0012]
On the other hand, when the bolt 25 is tightened using the socket 23, the bolt 25 is often tightened for a while even after sitting on an iron plate or the like. In such a case, the bolt 25 is hardly rotated and the hammer 15 Since energy is stored in the socket 23 and the hammer 15 repels from the anvil 17 when the energy of the socket 23 is released, the repulsion is greater than when the screw 24 is tightened to wood.
[0013]
FIG. 6 shows the operation of the hammer 15 in this case.
[0014]
The hammer claw 15b strikes the anvil 17b (A2 in the figure), and the hammer 15 repels from the anvil claw 17, but the repulsion is large and the hammer 15 hits the stopper 22 (A3 in the figure). Further, since the repulsion from the stopper 22 and the spindle 14 are constantly rotating, the hammer 15 is rapidly accelerated through the ball in the cam groove of the spindle 14, and the hammer 15 descends along the cam groove, and the hammer claw is moved. The head 15c of 15b collides with the head 17c of the anvil claw 17b (A4 in the figure). Further, the hammer claw head 15c slides on the anvil claw head 17c and moves to the cam bottom while slightly falling (B1 in the figure), and thereafter, the hammer 15 again strikes the anvil claw 17b (B2 in the figure).
[0015]
When the bolt 25 is tightened for a while after sitting on an iron plate or the like, the above-described operation of the hammer 15 may occur.
[0016]
Here, in the case of the above-described tightening, the energy stored in the socket 23 is large, the socket 24 is damaged at an early stage, and the inconvenience of increasing the number of socket replacements has occurred, or the rotation having a higher power has occurred. Tightening of bolts using sockets is not recommended for hammering tools, and it is described as "only for wood screws" so that only screws are tightened. Workers who want to tighten bolts using sockets should use this tool. Must be avoided.
[0017]
An object of the present invention is to provide a rotary impact tool having a rotary impact generating mechanism for tightening screws and bolts and a speed reducing mechanism, by reducing the speed at which the hammer hits the anvil when tightening the bolt, thereby providing a more durable socket. It is an object of the present invention to obtain a rotary hitting tool capable of performing the following.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a non-slip surface for the head of the anvil claw and the head of the hammer claw, or forms a plurality of irregularities, or forms the head of the anvil claw on a convex surface and the other hammer claw. Is characterized in that its head is formed in a concave surface.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
[0020]
FIG. 8 shows the surface of the hammer claw head 15c and the spindle claw head 17c formed by a rough shot or an uneven forging die.
[0021]
FIG. 9 shows a case in which several triangular grooves are formed on the spindle claw head 17c along the long axis of the claw, and a similar groove is also formed in the hammer claw head 15c. The shape of the groove may be square, and the direction of the groove may be a groove along the radial axis from the central axis of the spindle 17.
[0022]
8 and 9 show the rotational speed of the hammer when both the hammer claw head 15c and the spindle claw head 17c are positively non-slip and the hammer claw head 15c contacts the spindle claw head 17c. Can be reduced, and the energy when the hammer claw 15b strikes the spindle claw 17b thereafter can be reduced.
[0023]
FIG. 10 shows a hammer claw head 15c having a convex surface and a spindle claw head 17c having a concave surface.
[0024]
FIG. 11 shows the trajectory of the hammer operation. After the hammer claw head 15c hits the spindle claw head 17c, the hammer 15 conventionally moves with 26 trajectories. Draw the trajectory of Therefore, a friction loss occurs because the hammer 15 is lifted upward, and the impact force on the spindle decreases due to a decrease in the rotation speed.
[0025]
【The invention's effect】
As described above, according to the present invention, it is possible to reduce the rotation speed of the hammer when the rebound of the hammer is large, such as when bolting, and the head of the hammer comes into contact with the head of the spindle claw. Therefore, by reducing the rotational energy when the hammer claw strikes the spindle claw, the load on the socket is reduced and the life of the socket is improved.
[0026]
In addition, notation such as “only for wood screws” becomes unnecessary, and anxiety to the worker is also eliminated.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of a rotary impact tool.
FIGS. 2A and 2B are representative socket diagrams of the rotary impact tool shown in FIG. 1 when bolts are tightened, wherein FIG. 2A is a left side view, FIG. 2B is a partially broken front view, and FIG. FIG.
FIG. 3 is a perspective view of a representative screw tightened with the rotary impact tool of FIG. 1;
FIG. 4 is a perspective view of a representative bolt tightened with the rotary impact tool of FIG. 1;
FIG. 5 is an operation diagram of a typical hammer when a screw is tightened by the rotary impact tool of FIG. 1;
FIG. 6 is an operation diagram of a typical hammer when a screw is tightened with the rotary impact tool of FIG. 1;
FIG. 7 is a perspective view of a conventional hammer and anvil, wherein (a) shows a hammer and (b) shows an anvil.
FIG. 8 is a perspective view of a hammer and an anvil in the embodiment of the present invention, wherein (a) shows a hammer and (b) shows an anvil.
FIG. 9 is a perspective view of a hammer and an anvil in another embodiment of the present invention, wherein (a) shows a hammer and (b) shows an anvil.
FIG. 10 is a perspective view of a hammer and an anvil in still another embodiment of the present invention, wherein (a) shows a hammer and (b) shows an anvil.
11 is a trajectory diagram of the hammer operation in FIG.
[Explanation of symbols]
1 is a housing, 2 is a motor, 9 is a planetary gear, 10 is a hammer case, 14 is a spindle, 14a is a spindle side cam groove, 15 is a hammer, 15a is a hammer side cam groove, 15b is a hammer claw, and 15c is a hammer claw head. Part, 16 is a ball, 17 is an anvil, 17b is an anvil claw, 17c is an anvil claw head, 20 is a cross screw bit, 22 is a stopper, 23 is a bolt tightening socket, 24 is a cross screw, and 25 is a bolt.

Claims (3)

A rotation provided with a hammer having a hammer claw that is axially movable to a rotationally driven spindle and that transmits a rotational force from the spindle, and an anvil having an anvil claw that is given a rotary impact force by the hammer claw. A rotary impact tool, wherein the head of the anvil claw and the head of the hammer claw are non-slip. A rotation provided with a hammer having a hammer claw that is axially movable to a rotationally driven spindle and that transmits a rotational force from the spindle, and an anvil having an anvil claw that is given a rotary impact force by the hammer claw. A rotary impact tool, wherein a plurality of irregularities are formed on a head of the anvil claw and a head of the hammer claw. A rotation provided with a hammer having a hammer claw that is axially movable to a rotationally driven spindle and that transmits a rotational force from the spindle, and an anvil having an anvil claw that is given a rotary impact force by the hammer claw. A rotary impact tool, wherein the head of the anvil claw is formed in a convex surface, and the head of the hammer claw is formed in a concave surface.

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