JPH0562742U - Torque limiter - Google Patents

Abstract

(57) [Summary] [Purpose] To enhance the safety when returning the torque limiter from the disconnected state to the connected state. [Structure] A ball 6 is arranged in a field core 4 having a permanent magnet 5 provided therein, and a counterbore portion 13a which meshes with the ball 6 in an armature 13 supported by a hub 7 via a leaf spring 8.
Formed. An armature guide 10 is integrally fixed to the armature 13 with a bolt, and a return lever 1 that can be brought into contact with and separated from an end surface 10b of the armature guide 10.
4 is provided. When the driven shaft 3 is overloaded, the armature 10 withdraws the ball 6 against the magnetic attraction of the permanent magnet 5. The retracted armature 10 is moved to the field core 4 side by rotating the return lever 14 in the clockwise direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a torque limiter in which torque transmission is interrupted by disengagement of engagement of engagement means due to occurrence of overload.

[0002]

[Prior Art]

 In the torque limiter disclosed in Japanese Utility Model Publication No. 1-111923, a field core as a first rotating member having a permanent magnet installed therein is supported on a rotating shaft so as to be free to rotate, and spline-fitted on the rotating shaft. An armature as a second rotating member is magnetically attracted to the field core via a ball. A plunger whose tip is pressed against the outer peripheral surface of the rotary shaft by a compression coil spring is installed inside the boss of the armature.For example, the armature on the driven side is overloaded and resists the magnetic attraction force of the permanent magnet. When the engagement between the ball and the groove formed in the armature is released, the armature moves over the ball and retracts, so that the plunger moves to the D-shaped cut surface formed on the nut on the rotating shaft.

Therefore, the armature tries to move (return) to the field core side due to the external vibration or the magnetic attraction force of the permanent magnet, but since the plunger is hooked on the end surface of the step portion of the rotating shaft, the armature is in the retracted position. It is held stationary. When the nut is rotated to raise the plunger to the outer peripheral surface of the rotating shaft, the armature is ready to move to the field core side.

[0004]

[Problems to be solved by the device]

 Such a torque limiter is built into the drive mechanism of a machine tool and has a good reputation as a safety joint.However, when torque transmission is interrupted due to overload on the driven side, the operator is the drive source. There were cases where a tool was inserted into the drive mechanism in an attempt to connect the torque limiter without stopping the motor. Therefore, there is a risk of causing occupational accidents and safety measures must be dealt with immediately.

When the torque limiter is connected without stopping the drive source, the counterbore part of the armature forming the engaging means and the ball arranged in the field core are safely meshed with each other, and the armature is brought into the field core without being connected. I will turn around. Machine tools cause machining errors, so it is necessary to prevent such turning.

[0006]

[Means for Solving the Problems]

 In order to achieve the object, according to the present invention, the first rotating member supported by the rotating shaft so as to be free to rotate in the axial direction is supported, and the first rotating member has its front face opposed to the rotating shaft in the axial direction. A second rotating member integrally connected in a retractable manner, first engaging means interposed between the second rotating member and the rotating shaft, and between the first rotating member and the second rotating member At least one of the first rotating member and the second rotating member includes an intervening second engaging member and a permanent magnet provided in one of the first rotating member and the second rotating member. It is characterized in that one of the rotating members is provided with a pressing means that can be brought into and out of contact with the handle by operating it.

[0007]

【Example】

 1 to 3 show a torque limiter according to an embodiment of the present invention, FIG. 1 is a front view, FIG. 2 is a cross-sectional view of a state in which a second engaging means is engaged, and FIG. 3 is a second engaging means. FIG. 4 is a side view with a partial cross section in a state where the mesh is disengaged. The torque limiter 1 is mounted on the drive shaft 2 and the driven shaft 3 in the drive mechanism of the machine tool, and is configured as a butt shaft type which is different from the conventional through shaft type (actual Kaihei 1-1119923).

A field core 4 as a first rotating member is integrally attached to the drive shaft 2 by a span ring (not shown), and a plurality of permanent magnets 5 are provided in the field core 4 at circumferential intervals. Has been done. In addition, a plurality of balls 6 are disposed between the permanent magnets 5 so as to be rollable in the recesses 4a. A hub 7 is fitted into a concave portion at the center of the field core 4 via a bearing, and the hub 7 is attached to the hub 7 by a spun ring (not shown) together with a boss 9 fixed by a bolt via a base portion of a leaf spring 8. It is integrally attached to the driven shaft 3.

An armature holder 10 is slidably fitted to the outer periphery of the boss 9 via a first engaging means, and a groove 10a formed in an inner peripheral surface of the armature holder 10 constituting the first engaging means. The ball 11 arranged in the recess of the boss 9 is meshed with the spring force of the compression coil spring 12. An armature 13 is fixed to the armature holder 10 with a bolt through a free end portion of a leaf spring 8. The armature holder 10 and the armature 13 can rotate integrally with the hub 7 and can move in the axial direction.

On the plane of the armature 13 facing the field core 4, a counterbore 13a is formed at the same position as the recess 4a formed on the field core 4, and the counterbore forming these second engaging means. The air gap between the armature 13 and the field core 4 becomes zero due to the engagement of the ball 13 with the ball 13a. When the driven shaft 3 is overloaded and the engagement between the counterbore 13a and the ball 6 is disengaged against the magnetic attraction of the permanent magnet 5, the armature 13 gets over the ball 6 and retreats, causing the armature to move backward. An air gap is formed between 13 and the field core 4, and the magnetic force of the permanent magnet 5 that magnetically attracts the armature 13 to the field core 4 side suddenly weakens. Further, the ball 11 on the boss 9 side meshes with the groove 10a of the armature guide 10 by the spring force of the compression coil spring 12, and the armature 13 is held stationary in the retracted position as shown in FIG.

Next, a description will be given of the return lever 14 as a pressing means which is an essential part of the present invention. A pair of mounting plates 15 are fixed inside the housing of the machine tool, and a support shaft is provided between these mounting plates. 16 is fixed. A leg 17 bent into a substantially U-shape is rotatably supported on the support shaft 16, and a handle 18 extended to the outside of the machine tool casing is fixed to the leg 17. ing. The return lever 14 including the leg portion 17 and the handle 18 is normally tilted as shown in FIG. 3 by a tension spring (not shown), and a pair of rollers 19 rotatably attached to the leg portion 17 is provided on the armature guide 10. It faces the end surface 10b of the cylindrical boss portion with a gap.

In the torque limiter having such a configuration, the armature 13 is magnetically attracted to the field core 4 via the second engaging means composed of the spot facing 13 a and the ball 6, so that the drive shaft 2 and the driven shaft are driven. The shaft 3 rotates together. Here, when an overload occurs on the driven shaft 3 side and the armature 13 goes over the ball 6 and retreats against the magnetic attraction force of the permanent magnet 5, the magnetic force of the permanent magnet 5 suddenly weakens and Since the first engaging means composed of the groove 10a of the armature holder 10 and the ball 11 mesh with each other, the armature 13 is held stationary in the retracted position. Therefore, torque transmission from the drive shaft 2 to the driven shaft 3 is cut off.

After removing the cause of the overload on the driven shaft 3 side, as shown in FIG. 3, the return lever 14 tilted by the spring force of the unillustrated tension spring is moved by the handle 18 to move as shown in FIG. When raised in this way, the roller 19 of the return lever 14 hits the end surface 10b of the armature guide 10, and the groove 10a of the armature guide 10 and the ball 11 arranged on the boss 9 are disengaged. Then, the armature 13 returns to the field core 4 side by the restoring force of the leaf spring 8 and the magnetic attraction force of the permanent magnet 5, and the groove 6a of the armature 13 and the ball 6 arranged in the field core 4 as shown in FIG. And are meshed and connected to each other, so that torque can be transmitted. In the above description, the return lever 14 is exemplified as the pressing means in which the pair of rollers 19 is rotatably attached to the leg portion 17, but the pair of discs to which the friction plates are fixed is fixed to the leg portion 17. As a result, it can be used as a turning prevention lever described later.

Next, a torque limiter according to another embodiment of the present invention will be described. 4 to 6 show another embodiment of the torque limiter, FIG. 4 is a front view, FIG. 5 is a sectional view showing a state in which the second engaging means are engaged, and FIG. 6 is a state before the second engaging means is engaged. It is sectional drawing of a state. Like the torque limiter 1 described above, the torque limiter 20 is mounted on the drive shaft 2 and the driven shaft 3 in the drive mechanism of the machine tool, and the components having substantially the same constituents are designated by the previously used reference numerals. The explanation is attached by attaching and the explanation is not repeated.

In this torque limiter 20, the boss 9 has a shape composed of a large-diameter disk portion 9a and a small-diameter cylindrical portion 9b, and the disk portion 9a is provided with a plurality of recesses 9c that open toward the side opposite to the hub 7. A compression coil spring 21 is provided in the recess 9c, and a spline boss 23, which is movable only in the axial direction with a key 22, is fitted into the cylindrical portion 9b to prevent the snap ring 24 from coming off. The spline boss 23 is pressed against the hub 7 side by the compression coil spring 21, and the friction plate 25 fixed to the side surface comes into contact with and separates from the end surface 10b of the armature holder 10.

A lever 27 for preventing continuous rotation as a pressing means, which is composed of a leg portion 27a to which a pair of pins 26 inserted into the groove of the spline boss 23 are fixed and a handle 27b fixed to the leg portion 27a. Is swingably supported by a support plate 28 fixed inside the housing of the machine tool, and the entrainment prevention lever 27 is in a standing state as shown in FIG. 5 by the spring force of the tension spring 29. In this state, the spline boss 23 is moved to the snap ring 24 side by the spring force of the compression coil spring 21.

The torque limiter 20 having such a structure operates in the same manner as the torque limiter 1 described above, but here, it is provided in the counterbore 13 a of the armature 13 and the recess 4 a of the field core 4. When the armature 13 is returned from the disengaged state of the ball 6 by operating the handle 27b as shown in FIG. 6, the flat surface of the armature 13 may be hit by the ball 6 and magnetically attracted to the field core 4. In such a case, when the drive shaft 2 rotates, the armature 13 rotates together with the field core 4 by the magnetic attraction force of the permanent magnet 5. Therefore, when the armature 13 is returned, the handle 27b is always rotated counterclockwise to press the friction plate 25 against the end surface 10b of the armature holder 10 to brake the rotation of the armature 13. When the counterbore 13a of the armature 13 and the ball 6 arranged in the recess 4a of the field core 4 mesh with each other and the armature 13 is magnetically attracted to the field core 4, the handle 27a is set in a free state, so that the spline is free. Since the boss 23 is separated from the armature holder 10 by the spring force of the compression coil spring 21, the braking of the armature 13 is released.

In the above description, the torque limiter is a butt shaft type, but it may be a through shaft type, and the second engaging means may be formed by engaging teeth instead of a spot facing portion and a ball. Furthermore, the armature and the hub may be connected by a spline groove instead of the leaf spring connection, and the first engaging means is for holding the opening as disclosed in Japanese Utility Model Laid-Open No. 63-178633. The armature and the second permanent magnet may be used, and the pressing means may be brought into contact with or separated from the open-holding armature.

【effect】

 As described above, according to the present invention, since the torque limiter is provided with the pressing means so that the handle is moved so as to change from the disengaged state to the connected state, it is possible to prevent the occurrence of the industrial accident as in the past. Further, it is possible to prevent rotation of the driven member, which is the driven side, until the engagement means engages with each other, and prevent machining error of the machine tool.

[Brief description of drawings]

FIG. 1 is a front view of a torque limiter of the present invention.

FIG. 2 is a cross-sectional view of a state in which the second engaging means of FIG. 1 is connected.

FIG. 3 is a side view showing a partial cross section of a state in which a second engaging means corresponding to FIG. 2 is disengaged.

FIG. 4 is a front view of a torque limiter according to another embodiment of the present invention.

5 is a cross-sectional view of a state in which the second engaging means of FIG. 4 is connected.

FIG. 6 is a sectional view showing a state in which a second engaging means corresponding to FIG. 5 is disengaged.

[Explanation of symbols]

 1 torque limiter 4 field core (first rotating member) 5 permanent magnet 6 ball 8 leaf spring 13 armature (second rotating member) 14 return lever 20 torque limiter 27 anti-rotation lever

Claims (1)

[Scope of utility model registration request] 1. A first rotating member, which is supported by a rotating shaft so as to be free-rotating and whose axial movement is restricted, and a front face facing the first rotating member, which is integrally connected to the rotating shaft so as to be axially retractable. A second rotating member, a first engaging means interposed between the second rotating member and the rotating shaft, and a second engaging member interposed between the first rotating member and the second rotating member. And a permanent magnet provided inside either the first rotating member or the second rotating member, and the handle is provided on at least one rotating member of the first rotating member and the second rotating member. A torque limiter characterized by comprising a pressing means that can be brought into and out of contact with an operation.