JP2924568B2 - Electromagnetic coupling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro electromagnetic coupling device used for OA equipment and the like.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view in the axial direction showing a conventional electromagnetic coupling device of this kind, and FIG. 4 is a view of FIG. In the figure, 1 is a disk-shaped yoke made of a magnetic material, 2 is a bobbin having a built-in excitation coil 3, 4 is a rotor made of a magnetic material having an L-shaped cross section, and 5 is connected to the excitation coil 3. A lead wire 6 is a rotary shaft of a magnetic material which is integral with the rotor 4 and serves as a first connection main body, and 7 has a gap g in the axial direction with the rotor 4 and is movable in the axial direction via a spring described later. Of a magnetic material supported by a rotating member, and 8
Has a second gear 9 for meshing with a gear (not shown).
The rotating member 10, which is the main body of connection, is a spring, and is fixed to the armature 7 and the rotating member 8 by rivets (not shown), respectively. It is provided as possible. 11 is a holder fixed to the yoke 1 to prevent the yoke 1 from rotating together with the rotating shaft 6, 12 is a retaining ring provided on an end face of the rotating shaft 6 to prevent the rotating member 8 from coming off,
Reference numeral 13 denotes a flange portion provided on the rotating shaft 6 for preventing the bobbin 2 from coming out of the inside of the rotor 4.

[0003] The electromagnetic coupling device configured as described above operates as follows. That is, when a voltage is applied from a power source (not shown) to the exciting coil 3 via the lead wire 5, a magnetic flux Φ is generated in a magnetic path shown by a dotted line, and the armature 7 overcomes the elastic force of the spring 10 by the attraction force, and Is sucked. Therefore, the power transmitted to the gear 9 in contact with the rotor 4 is transmitted to the rotating member 8, the armature 7, the rotor 4, the rotating shaft 6.
Through a load (not shown). When the voltage of the exciting coil 3 is removed, the magnetic flux Φ disappears, the armature 7 returns to the original position by the elastic force of the spring 10, the gap g with the rotor 4 is maintained, and the transmission of power is stopped.

[0004]

In the conventional electromagnetic coupling device, the yoke 1 and the rotary shaft 6 slide directly without providing an air gap as described above, so that the magnetic flux Φ easily passes and the exciting coil 3 is reduced in size. However, since the yoke 1 and the rotating shaft 6 are made of a magnetic material, a suction force acts on the sliding portion, and the surface pressure of the sliding portion increases. For this reason, the allowable number of rotations of the yoke 1 and the rotating shaft 6 is reduced, and it is necessary to reduce the number of rotations used in order to secure the life, and there is a problem that the application is limited.

If the rotational speed exceeds the allowable rotational speed, seizure may occur between the yoke 1 and the rotating shaft 6 to cause a loss of power or, in the worst case, to lock. Will no longer serve as a connecting device,
Further, there is a problem that the holder 11 is damaged or the lead wire 5 is cut due to the lock. Further, there is a problem that the total rotation speed is limited even if the rotation speed is lower than the allowable rotation speed described above, and the life cannot be extended.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a structure in which the yoke does not directly slide on the rotating shaft and the rotor. An object of the present invention is to obtain an electromagnetic coupling device that can be manufactured for a long time and at low cost.

[0007]

SUMMARY OF THE INVENTION The electromagnetic coupling device according to the invention, between the convex portion becomes the rotation axis integrally with the rotor,
Place the yoke respectively rotor and protrusion be a clearance
The yoke is fixed to the bobbin, and the yoke,
It is obtained as over data and not directly slid by.

[0008]

According to the present invention, since the yoke does not slide directly, the allowable rotational speed can be increased.

[0009]

【Example】

Embodiment 1 FIG. One embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view in the axial direction.
In the figure, reference numeral 14 denotes a yoke having a cylindrical portion 14a, which is manufactured by pressing a steel plate material. 14b is a holder integrated with the yoke 14, 15 is a bobbin, which is mechanically connected to the yoke 14 and is made of plastic. The bobbin 15 is fixed to an external fixing member (not shown) via a holder 14b of the yoke 14, and prevents the bobbin 15 from rotating together with the rotating shaft 6. Reference numeral 16 denotes a disk-shaped plate which is a protrusion formed integrally with the rotating shaft 6 from a sintered magnetic material and constituting a part of a magnetic circuit. The cylindrical portion 14a of the yoke 14 has a gap with the inner periphery of the rotor 4, and a gap is also provided between the yoke 14 and the plate 16, so that none of them slides directly.

If the rotating shaft 6 made of a magnetic material and the bobbin 15 made of a different material such as plastic are directly slid in this way, there is no sticking as in the prior art and stable sliding characteristics. Is obtained, the permissible rotation speed can be greatly increased, and the life is prolonged.

Further, if the yoke 14 is provided with a cylindrical portion 14a extending along the inside of the rotor 4, the area where the rotor 4 and the yoke 14 face each other due to the gap can be made very large, and the plate 16 can be attached to the rotating shaft 6. When integrally formed of an iron-based sintered alloy, there is no air gap between the both 6 and 16, so that the magnetic resistance is reduced and the magnetomotive force is reduced. This leads to a reduction in the size of the coil 3, so that the device itself can be made smaller and can be manufactured at a significantly lower cost together with the press manufacturing of the yoke 14. Furthermore, since the holder 14b can also be formed integrally with the yoke 14, the number of parts can be reduced and the holder 14b can be manufactured at low cost. Needless to say, the thickness of the yoke 14 is slightly larger than the outer diameter of the lead wire 5 so that the yoke 14 can be held by the lead wire 5. Further, if the bobbin 15 and the rotating shaft 6 are made of oil-impregnated material, the slidability is greatly improved and the effect is enormous.

Embodiment 2 FIG. In the first embodiment, the yoke 14 having the cylindrical portion 14a is shown. However, as shown in FIG. 2, a dish-like portion 14c is provided to form the yoke 14A, and the dish-like portion 14c of the yoke 14A is located inside the plate 16 of the rotating shaft 6. Bobbin 15
The same effect can be obtained by inserting the cable between them and fixing it to the side surface of the bobbin 15. Also in this case, a gap is provided between the plate-like portion 14c of the yoke 14A and the plate 16 so as to prevent direct sliding.

[0013]

As described above, according to the present invention, since the yoke and the rotary shaft do not slide directly, the allowable number of rotations of the rotary shaft can be greatly increased, the service life can be prolonged, and the manufacturing cost can be reduced. Is obtained.

[Brief description of the drawings]

FIG. 1 is an axial sectional view showing Embodiment 1 of the present invention.

FIG. 2 is an axial sectional view showing Embodiment 2 of the present invention.

FIG. 3 is an axial sectional view showing a conventional device.

FIG. 4 is a view of FIG. 3 as viewed from the left.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 Coil 4 Rotor 5 Lead wire 6 Rotating shaft 8 Rotating member 14 Yoke 14a Yoke cylinder part 14A Yoke 15 Bobbin 16 Plate

Claims (3)

(57) [Claims] 1. A rotating shaft of a magnetic material serving as a first connecting main body, a rotating member serving as a second connecting main body rotatably loosely fitted to the rotating shaft, and an opening opening in a friction surface and an axial direction. A rotor made of a cylindrical magnetic material having a portion and fixed at least in the rotational direction to the rotating shaft, facing a friction surface of the rotor via an axial gap g, and at least rotating the rotor in the rotating direction. Armature, a bobbin inside the rotor, rotatably disposed on the rotary shaft and wound with an exciting coil, and an end face of the rotary shaft for holding the bobbin in the rotor. And magnetic circuit
A convex portion protruding from the outer periphery, and a gap is provided between the outer peripheral surface of the convex portion and the inner peripheral surface of the opening of the rotor, and is inserted and disposed so as to be relatively rotatable with the convex portion. And a yoke made of a magnetic material for preventing rotation of the bobbin. 2. The yoke according to claim 1, wherein the yoke is formed in a cylindrical shape, surrounds the outer periphery of the bobbin, is fixed to the bobbin, and is disposed between the inner periphery of the rotor and the convex portion of the rotating shaft. Electromagnetic coupling device. 3. A yoke according to claim 1, wherein said yoke is provided with a dish-shaped portion extending in a radial direction, said dish-shaped portion being inserted between a projection of a rotating shaft and a bobbin and fixedly supported by said bobbin. Empty between the department
An electromagnetic coupling device , wherein a gap is provided so that sliding is performed between the convex portion and the bobbin .