JP2006250283A - Torque limiter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost and to make it possible to connect a rotator and a permanent magnet without generating fragments, shaving powder or the like. <P>SOLUTION: The torque limiter 2 is constructed such that an internal rotator 12 is rotatably incorporated in an external rotator 4, the permanent magnet 18 is assembled in one of the external rotator 4 and the internal rotator 12, for example, in the rotator 12 and a semihard magnetic member 8 facing to the permanent magnet 18 is assembled in the other rotator 4. An elastic member 22 is provided between the rotator 12 and the permanent magnet 18 as a means for assembling the permanent magnet 18 in the rotator 12. The elastic member 22 presses both the rotator 12 and the permanent magnet 18 at least in the radial direction. As a result, the permanent magnet 18 is secured to the rotator 12 due to the elastic force of the elastic member 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a torque limiter using magnetic force.

2. Description of the Related Art Conventionally, a torque limiter using magnetic force is known in which a permanent magnet is fixed to a rotating member by bonding (see, for example, Patent Documents 1 and 2). Also, when a plurality of convex portions are provided on either the resin rotating body or the permanent magnet and the permanent magnet and the resin rotating body are fitted together, the tip of the convex portion is made of the resin rotating body or the permanent magnet. Conventionally known is one in which either one is in pressure contact (see, for example, Patent Document 3).
Japanese Patent Laid-Open No. 7-7919 JP-A-6-221341 JP 2004-308767 A

In order to fix the permanent magnet to the rotating member, it is easiest to fix the permanent magnet by press-fitting, and the number of manufacturing processes is small, and the manufacturing can be performed at low cost. However, a permanent magnet having a strong magnetic force is generally formed of a material having extremely low elasticity. Therefore, if the permanent magnet is press-fitted into the rotating member to fix them, the pressure applied to the permanent magnet becomes too large, and the permanent magnet will be cracked. The method of fixing by press fitting cannot be adopted.
In the prior art disclosed in Patent Documents 1 and 2, a permanent magnet is fixed to the rotating member by adhesion. However, in this method, high fitting accuracy between the rotating member and the permanent magnet is required, and high accuracy is required, so high cost is inevitable. Moreover, even in the manufacturing process, it is not easy to evenly interpose the adhesive between the rotating member and the permanent magnet manufactured with high fitting accuracy, and this is also a high cost factor. In addition, even after the adhesive is interposed, it is necessary to leave it for a certain period of time until it is completely bonded, and this is also a high cost factor.
In order to solve this, the prior art shown in Patent Document 3 has been proposed by the present applicant. In this prior art, when a shaft member for attaching a permanent magnet is made of resin, a protrusion is formed on one of the shaft member and the permanent magnet, and the protrusion is formed on the permanent magnet, the shaft member and the permanent magnet When the other resin shaft member is scraped off by this projection to fix both, and the projection is formed on the resin rotating member, the projection is formed by fitting the shaft member and the permanent magnet. Both ends are fixed by being scraped off. By adopting such a configuration, it becomes possible to incorporate a permanent magnet into the shaft member without taking a method by bonding, and solves the above-mentioned drawbacks of the method by bonding.
However, this prior art has been found to have the following drawbacks. That is, by scraping off a part of the shaft member as described above, the scraped pieces and shavings remain inside the case and adhere to the rotating bearing part, and thus the rotational friction resistance increases and fluctuates. As a result, the transmission torque as a torque limiter fluctuates.
The object of the present invention is to provide a torque limiter that eliminates the above-mentioned drawbacks of the prior art and enables the coupling of a shaft member and permanent ore that do not take a costly method of adhesion and does not generate debris or shavings. There is to do.

In order to achieve the above object, the present invention incorporates an inner rotator into an outer rotator so as to be relatively rotatable, and a permanent magnet is incorporated into one of the outer rotator and the inner rotator. In the torque limiter incorporating a semi-rigid magnetic body facing the permanent magnet in the rotating body, the means for incorporating the permanent magnet into the rotating body includes an elastic material interposed between the rotating body and the permanent magnet, The elastic material is configured to press both at least in the radial direction.
Moreover, this invention makes the said elastic material the cyclic | annular member arrange | positioned over the perimeter surface of the said rotary body.
Further, the present invention incorporates an inner rotating body into the outer rotating body so as to be relatively rotatable, and also incorporates a permanent magnet into one of the outer rotating body and the inner rotating body. In the torque limiter incorporating a semi-hard magnetic body facing the permanent magnet, the means for incorporating the permanent magnet into the rotating body includes an elastic material interposed between the rotating body and the permanent magnet. A pressing means for pressing at least in the radial direction, a first abutting surface in the rotational direction is formed on one side of the rotating body and the permanent magnet, and against the first abutting surface on the other side A second abutting surface facing the rotation direction is formed, and the first abutting surface and the second abutting surface are in contact with each other, thereby restricting relative movement of the rotating body and the permanent magnet in the rotating direction. Do And the rolling direction movement limiting means is made of an axial movement restricting means for restricting relative axial movement between the rotating body and the permanent magnet.

  According to the present invention, it is possible to couple a rotating body and a permanent magnet that do not increase costs and generate no debris or shavings.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
In FIG. 1, reference numeral 4 denotes an outer rotating body (housing) of the torque limiter 2, and a cap 6 and a semi-hard magnetic body (hysteresis ring) 8 are fixed to the inner diameter portion thereof.

The cap 6 is formed with a plurality of grooves 10 extending along the entire axial length. In the torque limiter composed of the permanent magnet and the semi-hard magnetic material that is the subject of the present invention, the opposed permanent magnets magnetize the semi-hard magnetic material and transmit a rotational force proportional to the area of the magnetic hysteresis loop. (Hysteresis torque) When the maximum transmission torque is exceeded, the permanent magnet and the semi-hard magnetic body rotate relative to each other while maintaining a constant torque. At that time, the semi-hard magnetic body generates heat, and the outer rotary body 4 (housing) The temperature rises. This increase in temperature causes the permanent magnet to demagnetize by the temperature coefficient of the permanent magnet, and as a result, the torque transmitted by the torque limiter decreases. The groove 10 formed in the cap 6 is formed between the inner peripheral surface of the outer rotating body 4 and the cap 6, and functions as an air vent hole 10 for releasing the heat in the outer rotating body 4 to the outside. And the magnetic force fall by the temperature rise in the outer side rotary body 4 is suppressed.

Reference numeral 12 denotes an inner rotating body (sleeve), and the vicinity of both ends is rotatably supported by the inner diameter portion of the outer rotating body 4 by bearings 14 and 16. A tubular permanent magnet 18 is fitted on the outer peripheral surface of the inner rotating body 12, and the outer peripheral surface of the permanent magnet 18 faces the inner peripheral surface of the semi-hard magnetic body 8 with a predetermined gap. .

As shown in FIG. 7, a concave portion 26 is formed on one end surface of the permanent magnet 18, and a convex portion 28 is formed on the collar portion 12 a of the inner rotating body 12 corresponding to the concave portion 26. The concave portion 26 and the convex portion 28 constitute abutting surfaces 26 and 28 that engage in the rotational direction and the axial direction. The abutting surfaces 26 and 28 are fitted to each other, thereby constituting a rotational direction movement restricting means for restricting relative movement in the rotational direction between the inner rotating body 12 and the permanent magnet 18.

This rotational direction movement restricting means restricts the movement in the forward and reverse two rotational directions, but when the relative rotational direction of the outer rotator 4 and the inner rotator 12 is only one direction, the relative rotational direction. The structure which restrict | limits rotation of only one direction may be sufficient. A retainer 20 is fixed to the inner rotating body 12, and an elastic material 22 made of an O-ring is fitted on the outer peripheral surface of the retainer 20.

The elastic material 22 is locked to the flange portion 20 a of the retainer 20, and is in pressure contact with the end portion of the permanent magnet 18 and the retainer 20. The permanent magnet 18 and the inner rotating body 12 are pressed in the radial direction, that is, in the direction perpendicular to the axial direction by the elastic force of the elastic material 22, and the permanent magnet 18 is free of play due to this pressing force. Thus, the inner rotating body 12 is fixed via an elastic material 22. Here, the elastic material 22 constitutes a pressing means that presses both the inner rotating body 12 and the permanent magnet 18 in the radial direction.

Due to the pressing force of the elastic material 22 in the axial direction, the abutting surface 26 formed on the end surface of the permanent magnet 18 abuts against the abutting surface 28 of the collar portion 12a of the inner rotating body 12, and the inner surface of the permanent magnet 18 is reached. The movement in the axial direction with respect to the rotating body 12 is locked. In the present embodiment, the abutting surfaces 26 and 28 and the elastic material 22 that urges the permanent magnet 18 in the axial direction with the retainer 20 as a fulcrum so that the abutting surfaces 26 and 28 come into contact with each other are the inner rotating body 12. And an axial movement restricting means for restricting the relative movement of the permanent magnet 18 in the axial direction.

  In the torque limiter 2 configured as described above, the relative rotation between the inner rotating body 12 and the outer rotating body 4 is restricted by the hysteresis torque generated between the permanent magnet 18 and the semi-hard magnetic body 8. When the rotational torque input to the rotator 12 or the outer rotator 4 becomes equal to or higher than the torque regulated by the hysteresis torque, the inner rotator 12 and the outer rotator 4 rotate relative to each other.

That is, if the input rotational torque is small, the rotation of the inner rotating body 12 or the outer rotating body 4 is transmitted to the outer rotating body 4 or the inner rotating body 12, but the input rotating torque exceeds a predetermined magnitude. Then, the inner rotator 12 and the outer rotator 4 rotate relative to each other so that an excessive load does not act on the outer rotator 4 or the inner rotator 12.

  In the first embodiment, the elastic material 22 is disposed only on one end side of the permanent magnet 18. However, as illustrated in FIG. 8, the elastic materials 24 and 22 made of O-rings are disposed on both ends of the permanent magnet 18. The elastic material 24 is locked by the collar portion 12b of the inner rotating body 12, the elastic material 22 is locked by the retainer 20, and both ends of the permanent magnet 18 are repelled by the elastic materials 24, 22 to rotate inward with the permanent magnet 18. It is good also as a structure which presses the body 12 to radial direction and an axial direction. In this case, the elastic materials 24 and 22 are pressing means for pressing both the inner rotating body 12 and the permanent magnet 18 in the radial direction, and at the same time, axial movement restriction means for restricting relative movement in the axial direction of the both. is there.

In the above embodiments, the permanent magnet 18 and the inner rotating body 12 are pressed both in the radial direction and in the axial direction by the elastic materials 22 and 24. As shown in FIG. The elastic material 22 locked between the flange portion 20a and the end surface 12c of the inner rotating body 12 is pressed against the inner peripheral surface of the permanent magnet 18 with the retainer 20 as a fulcrum, and perpendicularly to the inner surface of the permanent magnet 18. The rotating body 12 may be pressed only in the radial direction by the elasticity of the elastic material 22. In this case, the elastic material 22 constitutes a pressing means that presses both the inner rotating body 12 and the permanent magnet 18 in the radial direction.

In FIG. 9, the collar portion 20 a of the retainer 20 is in contact with the end surface of the permanent magnet 18 and locks the permanent magnet 18 so that the permanent magnet 18 does not shift in the axial direction with respect to the inner rotating body 12. In the present embodiment, the flange portion 20a of the retainer 20, the butting surface 28 of the collar portion 12a of the inner rotating body 12 and the butting surface 26 provided on the permanent magnet 18 are the axial directions of the inner rotating body and the permanent magnet. The axial direction movement restricting means for restricting the relative movement is configured.

  Further, as shown in FIG. 10, the elastic material 22 is compressed and disposed between the outer peripheral surface of the step 12 e of the inner rotator 12 and the inner peripheral surface of the permanent magnet 18, and the permanent magnet 18 and the inner rotator 12 are placed. It is good also as a structure pressed to radial direction. In FIG. 10, the elastic material 22 is locked between the wall surface 12 d of the step portion 12 e of the inner rotating body 12 and the collar portion 20 b of the retainer 20, and the collar portion 20 b of the retainer 20 is the end surface of the permanent magnet 18. This is locked against the inner rotating body 12 so as not to be displaced in the axial direction.

  In any of the above embodiments, an O-ring is used as the elastic material. However, the present invention is not particularly limited to the O-ring, and as shown in FIGS. A plurality of grooves 30 are provided on the outer peripheral surface along the axial direction thereof, a rod-shaped elastic material 32 is disposed in each groove 30, and the elastic material 32 is pressed against the inner peripheral surface of the permanent magnet 18. Also good.

Other configurations of the embodiment shown in FIG. 11 are substantially the same as those of the embodiment shown in FIG. Further, the present invention is not particularly limited to a configuration in which a semi-rigid magnetic body is incorporated in the outer rotating body and a permanent magnet is incorporated in the inner rotating body, and vice versa, that is, a permanent magnet is incorporated in the outer rotating body, It is good also as a structure which incorporated the semi-hard magnetic body in the inner side rotary body.

It is sectional drawing of the torque limiter concerning this invention. It is a right side surface of the torque limiter. This is the left side of the torque limiter. It is an expanded sectional view of the principal part of a torque limiter. It is a front view of an inner side rotary body. It is a right side surface of an inner side rotator. It is a left view of a permanent magnet. It is an expanded sectional view of the principal part of the torque limiter which shows other embodiment of this invention. It is an expanded sectional view of the principal part of the torque limiter which shows other embodiment of this invention. It is an expanded sectional view of the principal part of the torque limiter which shows other embodiment of this invention. It is sectional drawing of the torque limiter which shows other embodiment of this invention. It is the sectional view on the AA line which omitted the outside rotating body of the torque limiter.

Explanation of symbols

2 Torque limiter 4 Outer rotating body 6 Cap 8 Semi-rigid magnetic body 10 Air hole 12 Inner rotating body 14 Bearing 16 Bearing 18 Permanent magnet 20 Retainer 22 Elastic material 24 Elastic material 26 Abutting surface 28 Abutting surface 30 Groove 32 Elastic material

Claims (3)

An inner rotating body is incorporated into the outer rotating body so as to be relatively rotatable, and a permanent magnet is incorporated into one of the outer rotating body and the inner rotating body, and the other rotating body is opposed to the permanent magnet. In the torque limiter incorporating the semi-rigid magnetic body, the means for incorporating the permanent magnet into the rotating body includes an elastic material interposed between the rotating body and the permanent magnet, and the elastic material causes the both to at least radially. A torque limiter characterized by being configured to press. The torque limiter according to claim 1, wherein the elastic material is an annular member disposed over the entire circumference of the rotating body. An inner rotating body is incorporated into the outer rotating body so as to be relatively rotatable, and a permanent magnet is incorporated into one of the outer rotating body and the inner rotating body, and the other rotating body is opposed to the permanent magnet. In the torque limiter incorporating the semi-rigid magnetic body, the means for incorporating the permanent magnet into the rotating body includes an elastic material interposed between the rotating body and the permanent magnet, and the elastic material causes the both to at least radially. A first abutting surface in the rotational direction is formed on one side of the pressing means for pressing, the rotating body and the permanent magnet, and the other side is opposed to the first abutting surface in the rotational direction. A rotation direction movement control that forms a second abutting surface and restricts relative movement of the rotating body and the permanent magnet in the rotation direction by contacting the first abutting surface and the second abutting surface. It means a torque limiter, characterized in that it consists axial movement restricting means for restricting relative axial movement between the rotating body and the permanent magnet.

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