JP2887338B2 - Magnetic coupling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a pair of permanent magnets which are opposed to each other with a predetermined gap therebetween, and whose polarity is alternately changed in the circumferential direction. Field of the Invention The present invention relates to a magnetic coupling having a disk made of iron, and more particularly to a magnetic coupling capable of adjusting the magnetic force of the disk.

[0002]

2. Description of the Related Art A conventional magnetic coupling has a first yoke having a bottomed cylindrical shape, a side surface facing the bottom, and the first yoke.
A second yoke is detachably fitted and fixed to an opening of the yoke. Permanent magnets whose polarity is alternately changed in the circumferential direction are individually provided on the bottom of the first yoke and the side surface of the second yoke. The structure is fixed.

[0003] A disk made of a hysteresis material is interposed in the magnetic field of the pair of permanent magnets to induce magnetic induction, and is used as a hysteresis brake for braking a rotating shaft on which the disk is mounted (Japanese Patent Laid-Open No. Sho 52). -119747 gazette).

In such a magnetic coupling, when a pair of permanent magnets oppose each other with the same polarity, the magnetization of the disk becomes saturated, and the maximum braking torque is applied to the rotating shaft. When the pair of permanent magnets oppose each other with different poles, a minimum braking torque is applied to the rotating shaft.

[0005]

In recent years, such a magnetic coupling has been used as a load brake for applying a constant tension to a filament material such as a thread or a magnet wire. There is a problem that the adjustment work is difficult if the adjustment is for the force.

That is, the conventional magnetic coupling has a structure in which a second yoke is detachably fitted and fixed to an opening of a first yoke having a bottomed cylindrical shape, and the second yoke is formed by a magnetic force of a leakage magnetic circuit of each permanent magnet. The rotation load resistance of the second yoke with respect to one yoke increases. SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic coupling which can reduce the rotational load resistance to the adjustment of the magnetizing force of a disk and which can be easily adjusted.

[0007]

In order to achieve the above object, according to the present invention, there is provided a method in which a polarity is alternately changed in a circumferential direction.
A first yoke to which a permanent magnet is fixed, and a second permanent magnet which is arranged concentrically with the first yoke and opposed to the first permanent magnet with a predetermined gap and having the same pole arrangement are fixed. A second yoke, a rotary shaft rotatably supported by the first yoke and the second yoke via bearings individually fitted to the inner diameter surfaces of the yokes, A disk made of a hysteresis material rotatably interposed therein, and a non-magnetic material made of one of the first yoke and the second yoke integrally fixed to the other and detachably fixed to the other. And a coupling member.

According to another aspect of the present invention, an adjusting grip portion is provided on one of the yoke sides to which the coupling member is detachably fixed so as to face the end surface of the coupling member with a small gap. And

[0009]

Since the disk is magnetized in the magnetic field of the pair of permanent magnets, the rotation axis on which the disk is mounted rotates against the magnetic force of the disk. The magnetic force of the disk is
It is adjusted by changing the relative position of the pair of permanent magnets.

[0010]

1 is a sectional view, FIG. 2 is a side view, and FIG. 3 is a sectional view of FIG.
FIG. 3 is a sectional view taken along line A. The magnetic coupling shown in these drawings is used as a hysteresis brake for adjusting the tension of a linear material having a relatively small tension value such as a thread or a magnet wire.

Reference numeral 1 denotes a first yoke which is screwed to a front housing of a tension adjusting device (not shown). An annular flange 1a is formed on an outer peripheral surface on an outer side, and a first flange is formed on an inner side. An annular first permanent magnet 2 whose polarity is alternately changed in the circumferential direction is fixed. An annular second yoke 3 is disposed concentrically with the first yoke 1, and the second yoke 3, like the first yoke 1, has a flange as an adjustment grip portion on the outer peripheral surface on the outer surface side. A portion 3a is formed, and an annular second permanent magnet 4 having the same pole arrangement and fixed concentrically with the first permanent magnet 2 is fixed to the inner side surface.

Concave portions 1b and 3b are formed on the inner surfaces of the inner surfaces of the first yoke 1 and the second yoke 3, respectively, and a pair of bearings 5 in which outer rings are press-fitted into these concave portions 1b and 3b. Accordingly, the rotating shaft 6 is rotatably supported by the first yoke 1 and the second yoke 3. A hub 7 made of a non-magnetic material (synthetic resin material, aluminum material, or the like) is press-fitted and fixed to the rotating shaft 6. Cylindrical bosses 7 a and 7 b projecting from both sides of the hub 7 have bearings. 5 is in contact with the inner ring end face.

A disk 8 made of a hysteresis material is press-fitted and fixed to the outer peripheral surface of the hub 7.
The permanent magnet 4 is interposed at a predetermined gap. On the other hand, on the outer peripheral surface of the first yoke 1, a cylindrical coupling member 9 made of a non-magnetic material (synthetic resin material, aluminum material, or the like) fitted so that the end surface abuts on the flange portion 1a is integrated. Fixed.

An elongated hole 9a (see FIG. 2) in the circumferential direction is formed on the opposite side of the coupling member 9 from the first yoke 1, and an adjusting screw 10 inserted from the elongated hole 9a 2
The coupling member 9 is detachably fixed to the second yoke 3 by being screwed into the screw hole 3 c of the yoke 3.

In the magnetic coupling according to this embodiment, a coupling member 9 integrally fixed to the first yoke 1 in a state where the end faces of the boss portions 7a and 7b of the hub 7 are in contact with the inner ring end face of the bearing 5. A small gap S is formed between the end of the second yoke 3 and the flange 3a of the second yoke 3.

The magnetic joint having the above structure is the first type.
Since the disk 8 is magnetized in the magnetic field of the permanent magnet 2 and the second permanent magnet 4, when the rotating shaft 6 around which the disk 8 is pivoted rotates, the disk 8 changes its induced polarity while cutting off the magnetic field. Therefore, the braking torque of the rotating shaft 6 is set according to the magnetizing force of the disk 8 by the magnetic field of the first permanent magnet 2 and the second permanent magnet 4.

When the braking torque of the rotating shaft 6 is to be changed, the flange 3a serving as the adjusting grip of the second yoke 3 is gripped with one hand and held, and the adjusting screw 10 is loosened with the other hand.
Then, the first yoke 1 or the second yoke 3 is rotated to adjust the relative position between the first permanent magnet 2 and the second permanent magnet 4, and then the adjustment screw 10 may be retightened.

In this embodiment, the second yoke 3
The flange 3a as an adjustment grip is formed integrally with the
An adjustment grip portion made of, for example, a nonmagnetic material prepared in advance on the second yoke 3 may be integrally fixed.

[0019]

According to the magnetic joint of the present invention, the first yoke and the second yoke are joined by the joining member made of a non-magnetic material.
A leakage magnetic circuit bypassing the yoke to the second yoke is not formed, and the rotational load resistance of the second yoke with respect to the first yoke when adjusting the magnetic force of the disk is reduced, so that the adjustment operation is simplified.

In addition, an adjusting grip portion is provided on one of the yoke sides to which the coupling member is detachably fixed so as to oppose the end surface of the coupling member with a small gap, so that the magnetic force of the disk can be reduced. Adjustment work becomes easier. Furthermore, the end surface of the coupling member and the grip portion for adjustment are not in contact with each other, and it is possible to prevent an increase in rotational load resistance of the second yoke with respect to the first yoke due to sliding resistance between these members.

[Brief description of the drawings]

FIG. 1 is a sectional view of a magnetic coupling according to an embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st yoke 2 1st permanent magnet 3 2nd yoke 4 2nd permanent magnet 8 Disk 9 Coupling member 10 Adjustment screw

Claims (2)

(57) [Claims] 1. A first yoke to which first permanent magnets whose polarities are alternately changed in the circumferential direction are fixed, and which are arranged concentrically with the first yoke and opposed to the first permanent magnet with a predetermined gap. And a second yoke to which a second permanent magnet having the same pole arrangement is fixed, and which is rotatable to the first yoke and the second yoke via bearings individually fitted to the inner diameter surfaces of these yokes. A rotating shaft supported on the rotating shaft, a disk made of a hysteresis material axially mounted on the rotating shaft and rotatably interposed in the gap, and integrated with one of the first yoke and the second yoke And a coupling member made of a non-magnetic material, which is fixed to the other and detachably fixed to the other. 2. An adjusting grip portion, which is opposed to an end surface of the coupling member with a small gap, on one of the yoke sides to which the coupling member is detachably fixed. The magnetic joint according to claim 1, wherein