JPH0451216Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is installed between the driving side and the driven side of various types of equipment to transmit power, and prevents slipping when an overload occurs on the driven side. This invention relates to a torque limiter that prevents overload from being transmitted to the drive side.

[Conventional technology]

As this type of torque limiter, for example, one developed by the present applicant and disclosed in Japanese Utility Model Application No. 129926/1988 is known. To explain this simply, this torque limiter is a first torque limiter that is fitted onto a rotating shaft on the driving side or driven side so that rotation with the shaft is restricted by spline fitting etc., so that it can slide freely in the axial direction. comprising a rotating body, and a second rotating body rotatably fitted on the rotating shaft with side surfaces facing the first rotating body and restricted from moving in the axial direction; A permanent magnet magnetized in the axial direction is attached to either one of these rotating bodies. Furthermore, an engaging member such as a ball, a recess, or teeth is provided between the two rotating bodies, and the engaging member is engaged or disengaged as the first rotating body slides.

With this configuration, the side surface of the first rotating body is pressed against the side surface of the second rotating body by the magnetic attraction force of the permanent magnet, and the engaging means engages to create a connection between the two rotating bodies. power is transmitted. When an overload occurs on the driven side, the engagement member is disengaged and slides in the circumferential direction, so that the overload on the driven side does not reach the driving side. In this case, the two rotors are separated by the action of the engaging member, and an air gap is formed in the magnetic circuit of the permanent magnet, so that the magnetic attraction force is reduced, the power is cut off, and the driven side is stopped.

This type of torque limiter is generally provided with a transmission torque fine adjustment device as disclosed in, for example, Japanese Utility Model Publication No. 13536/1983. In this device, a screw hole corresponding to the ball as an engager of the engaging means is provided on the rotating body side, an adjusting screw is screwed into the screw hole, and a compression coil spring is interposed between the adjusting screw and the ball. This is what I did. By doing this, when the adjustment screw is rotated, the pressure force of the ball against the recessed hole changes via the compression coil spring, and the transmitted torque is adjusted.

[Problem that the invention attempts to solve]

However, in such conventional torque limiters, when an overload occurs and a relative displacement occurs in the circumferential direction between the rotating bodies on the driven side and the driving side via the ball of the engagement means, the compression coil spring As the spring force corresponding to the ball increases as it is compressed, depending on the magnitude of the overload force, the connecting force may not be cut off smoothly, resulting in the problem that it cannot necessarily be expected to function as a satisfactory overload safety device. It was hot.

[Means for solving problems]

In order to solve these problems, in the present invention, a permanent magnet is installed in one of the two rotating bodies whose sides face each other, and an engaging means is interposed between the two rotating bodies. A screw member for forming a magnetic circuit air gap is provided, the tip of which is in contact with the engager of the magnetic circuit, and is screwed into one of the rotating bodies so as to be freely adjustable forward and backward.

[Effect]

The engaging means is engaged by the magnetic attraction force of the permanent magnet, and power is transmitted between both rotating bodies. When an overload occurs on the driven side, the engaging means is disengaged and an air gap is formed in the magnetic circuit of the permanent magnet, so the magnetic attraction force decreases, power is cut off, and the driven side stops. In this case, since an air gap is formed in the magnetic circuit by the screw member, the magnetic attraction force is weakened and even a weak overload can cause the connection to come off.

〔Example〕

Figures 1 to 3 show an embodiment of the torque limiter according to the present invention, with Figure 1 being a longitudinal sectional view thereof, Figure 2 being a longitudinal sectional view AA of Figure 1, and Figure 3 being an enlarged longitudinal sectional view of the main parts. It is a front view. This embodiment shows an example in which the present invention is implemented between the driving side and the driven side of an NC lathe. The torque limiter 1 is connected to the rotating shaft 2 on the drive side.
It is provided with a hub 4 which is key-fixed to and prevented from coming off with a snap spring 3, and the hub 4 is integrally formed in a cylindrical shape with a boss 4a and a flange 4b. 5 is a snap spring 6 fitted to the boss 4a of the hub 4;
It is a plurality of bearings that are fixedly fitted and prevented from coming out by a snap spring 8, and a field core 7 as a first rotating body is fitted and fixed to the outer ring of the bearing with its movement in the axial direction restricted by a snap spring 8. It is formed to be rotatable with respect to the rotating shaft 2 via a bearing 5.
The field core 7 is drivingly connected to the driven side by meshing the gear 9 fixed to the stepped portion with the gear on the driven side. 10 is a screw hole into which a screw for fixing the gear 9 is screwed. On the other hand, an annular leaf spring 11 is attached to the end surface of the flange 4b of the hub 4.
is fixed with a plurality of setscrews 12 together with a stopper plate 19, which will be described later, and on its outer periphery is an armature as a second rotating body formed in an annular shape and having side surfaces facing the field core 7. 13 is fixed and elastically supported by a plurality of set screws 14, and as a result, the armature 1
3 is formed such that its rotation with respect to the rotating shaft 2 is restricted and is movable in the axial direction. Note that the leaf spring 11 is provided with a plurality of arcuate slits (not shown) for increasing the amount of deflection.

A plurality of recesses 7a are provided on the side surface of the field core 7 on the side of the armature 13 at locations that divide the outer circumference into a plurality of equal parts in the circumferential direction, and each recess 7a
A plurality of permanent magnets 15 whose axial direction of magnetization is alternately changed according to the circumferential arrangement are fitted inside. Further, on the side surface of the field core 7 on the armature 13 side, a plurality of recesses 7b, three in this embodiment, are located between the recesses 7a and adjacent recesses 7a that are equally spaced on substantially the same circumference. Field core 7 of armature 13
A plurality of counterbore portions 13a are provided on the opposing side surface, corresponding to each recessed portion 7b. 16
is a ball disposed within a space formed by each corresponding concave portion 7b and counterbore portion 13a,
The tip of an adjustment screw 17 screwed into a screw hole in the field core 7 is in contact with this ball 16.
The position of the ball 16 is adjusted by rotating the adjustment screw 17 back and forth. Numeral 18 is a nut for fixing the adjustment screw 17 after rotation adjustment. Note that the recessed portion 7b is formed by the ball 16.
Sometimes the opening is caulked to form an internal protrusion to prevent it from falling off.

Since the adjusting screw 17 causes the ball 16 to protrude from the end surface of the field core 7, if the armature 13 is pushed slightly by the ball 16, a gap between the armature 13 and the field core 7 will be formed as shown in FIG. An air gap indicated by the symbol t is formed at the permanent magnet 1.
5's magnetic attraction force becomes weaker, and even a weak overload can cause the connection to come off.

The hub 4 is attached with the set screw 12 together with the leaf spring 11.
The stopper plate 19 fixed to is integrally formed with an annular mounting portion 19a and outer flange portions 19b protruding from equidistant positions on the outer periphery thereof, and a concave portion formed in each outer flange portion 19b has a A second permanent magnet 20 is fitted respectively. By doing so, when the armature 13 moves toward the stopper plate 19 due to the action of the ball 16 during overload, the permanent magnet 20 attracts the armature 13 and restricts its movement.

The operation of the torque limiter configured as above will be explained. When the motor is turned on and the rotating shaft 2 rotates, a magnetic circuit of the permanent magnet 15 is formed between the adjacent permanent magnet 15, the field core 7, and the armature 13, and the armature 13 is connected to the leaf spring 1.
The rotation shaft 2 is attracted to the field core 7 against the elastic force of the rotary shaft 2 and connected by the ball 16, so that the rotation of the rotary shaft 2 is transmitted to the driven side via the gear 9.

When an overload occurs on the driven side, for example, on the cutting tool of a lathe, the braking is applied to the field core 7 side, and the counterbore 13a of the armature 13 climbs over the ball 16 and rotates circumferentially against the field core 7. Since the field core 7 and the armature 13 are separated from each other due to the phase shift in the direction, an air gap is formed in the magnetic circuit of the permanent magnet 15, and the connection by the engagement of the ball 16, that is, the transmission of power, is immediately interrupted. . Furthermore, in this device, the ball 16 is pushed by the adjusting screw 17 to slightly push the armature 13, thereby creating an air gap t in the magnetic circuit as shown in FIG.
Since this air gap t weakens the magnetic attraction force of the permanent magnet 15, the connection can be broken even under a weak overload. Furthermore, in the retracted position of the armature 13, the magnetic attraction force of the second permanent magnet 20 acts on the armature 13, which causes the permanent magnet 1
Because it overcomes the magnetic attraction of 5, armature 1
3 is magnetically attracted to the stopper plate 19. This cuts off the power transmission between the drive side and the driven side, so the drive power is immediately turned off, but since the armature 13 is attracted and its movement is restricted, the power on the drive side disappears. There is no possibility of the armature returning and re-engaging the ball 16. The magnetizing force of the permanent magnet 15 is designed based on the force relationship between the self-returning force of the leaf spring 11 and the magnetizing force of the permanent magnet 15.
Since the amount of movement of the armature 13 due to the detachment of the armature 13 is large, it is possible to reduce the spring load and the magnetizing force of the permanent magnet 20 relative to the amount of deflection of the leaf spring 11 when the armature 13 is joined to the field core 7. There is no problem that would reduce the torque transmitted between the core 7 and the armature 13.

FIG. 4 is an enlarged vertical sectional view of the main part of a torque limiter showing another embodiment of the present invention corresponding to FIG. 3, and in this embodiment, the ball 16 in the previous embodiment is not provided. , the adjustment screw 17A also serves as this. That is, the tip of the adjustment screw 17A is formed into a hemispherical shape and engages with the counterbore 13a, and the same air gap t as in the previous embodiment is provided between the armature 13 and the field core 7.
is formed. By doing so, the magnetic attraction force of the permanent magnet 15 is weakened in the event of an overload, and the connection is disconnected even under a weak overload, which is the same effect as in the previous embodiment.

[Effect of idea]

As is clear from the above description, in the torque limiter according to the present invention, a permanent magnet is installed inside one of the two rotating bodies with their sides facing each other, and an engaging means is interposed between the two rotating bodies. By providing a screw member for forming a magnetic circuit air gap whose tip is in contact with the engaging element of the engaging means and is screwed into the rotary body on the side of the permanent magnet so as to be freely adjustable forward and backward, the magnetic circuit of the permanent magnet can be adjusted. Since an air gap is formed by pressing the armature of the engager, the torque can be adjusted, and variations in the torque of this type of device can be dealt with by fine adjustment of the screw member, so the function as a torque limiter is improved.

[Brief explanation of drawings]

1 to 4 show an embodiment of the torque limiter according to the present invention, FIG. 1 is a longitudinal sectional view thereof, FIG. 2 is a sectional view along AA of FIG. 1, and FIG. 3 is an enlarged sectional view of the main parts. 4 is an enlarged vertical sectional view of a torque limiter corresponding to FIG. 3, showing another embodiment of the present invention. 1... Torque limiter, 2... Rotating shaft, 4...
Hub, 5...Bearing, 7...Field core, 11
...Plate spring, 13... Armature, 13a...
Counterbore portion, 15...Permanent magnet, 16...Ball,
17...adjustment screw, 18...nut, t...air gap.

Claims (1)

[Scope of utility model registration request] A pair of rotating bodies coaxially arranged with their sides facing each other and one movable in the axial direction, and a permanent magnet installed inside one of these rotating bodies to form a magnetic circuit between both rotating bodies. and an engaging means that is interposed between the two rotary bodies and engages with the magnetic attraction force of the permanent magnet, and a tip of the engaging means is brought into contact with an engager of the engaging means to rotate one of the rotating bodies. A torque limiter characterized in that a screw member for adjusting a magnetic circuit air gap is screwed into the body so as to be freely adjustable forward and backward.