JPH0323769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic powder clutch that is used in automobiles and various industrial machines, and which uses magnetic powder as a medium to transmit torque.

This type of electromagnetic powder clutch forms an operating gap between a drive member, which is a rotating body on the driving side, and a driven member, which is a rotating body on the driven side, and fills this operating gap with magnetic particles. It is known that the magnetic particles are bound by electromagnetic force, and the torque of the drive member is transmitted to the driven member by the magnetic attractive force between the magnetic particles and the friction between the magnetic particles and the operating surface.

In this type of clutch, the amount of magnetic particles as a working medium within the working gap greatly influences torque transmission performance. However, in a non-excited state, there is a problem in that the magnetic particles separate from the operating gap and the amount of magnetic particles in the operating gap decreases, which tends to cause a decrease in torque transmission ability. For this reason, in the past, a structure has been adopted in which a labyrinth seal is used to prevent the magnetic particles from falling out in a discrete manner. In either case, high processing and assembly precision is required, which increases costs and makes it difficult to prevent leakage of magnetic particles.

For this reason, conventionally, for example,
As described in Publication No. 2668, permanent magnets are installed in gaps and labyrinths where there is a risk of leakage, falling off, or scattering of magnetic particles, and this permanent magnet creates a magnetic field to prevent leakage or scattering of magnetic particles. Measures have been proposed.

In this type, leakage and scattering of magnetic particles are prevented by the magnetic force of the permanent magnet, so a predetermined amount of magnetic particles can be stored in the operating gap, and the torque transmission ability can be maintained at a high level.

However, since the conventional permanent magnet described above uses magnetic force to attract approaching magnetic particles and prevents them from scattering to the outside, more magnetic particles than necessary gather in this seal area, resulting in less magnetic particles than the required amount within the operating gap. There is a concern that the magnetic flux may decrease, and in a non-excited state, the magnetic particles that are attracted to and gathered at this seal portion are dragged around, causing a problem of generating idling torque.

Therefore, an object of the present invention is to maintain high torque transmission ability by preventing leakage, falling off, and scattering of magnetic particles, and also to prevent the magnetic particles from reducing in the non-excited state without worrying about reducing the amount of magnetic particles required within the operating gap. The purpose of the present invention is to provide an electromagnetic powder type clutch that prevents problems such as slipping torque caused by the clutch being twisted around.

The present invention provides annular permanent magnets at two locations on opposing surfaces of a drive member and a driven member, at the closest positions between the two excluding the operating gap, and at two locations sandwiching the operating gap. , and the opposing poles of these permanent magnets are the same. With this configuration, a magnetic field is formed by the annular permanent magnets provided on the opposing surfaces, so leakage of magnetic particles is prevented. and scattering,
Falling off is prevented, and the required amount of magnetic particles can be secured within the operating gap. Moreover, in this case, since the opposing poles of both annular permanent magnets are the same, the magnetic particles are repelled by these permanent magnets, and the magnetic particles are not attracted to the sealing part and collect, so that tangling is prevented and the gap torque is reduced. Occurrence is prevented.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In the figure, 1 is a drive member which is a rotating body on the drive side, and this drive member 1 accommodates an excitation coil 3 in yokes 2a and 2b made of magnetic material divided into left and right halves, and one yoke 2a. The flange 4 and the front cover 5 are attached, and a driven holder 6 is attached to the other yoke 2b, a rear labyrinth 7 is fixed to the driven holder 6, and a slip ring 8 as a current supply part is also attached to the driven holder 6. 8
It is constructed by integrally attaching.

When used as a vehicle clutch, the ring gear 1 is attached to the flange 4 through bolts 9...
0, and the ring gear 10 is connected to the crankshaft 11.
It is now connected to.

Brushes 12, 1 are attached to the slip rings 8, 8.
2 are in sliding contact with each other, and these brushes 12, 12 are attached to a brush holder 13. The brush holder 13 is fixed to a clutch cover (not shown).

The driven member 20 as a driven rotating body is made of a magnetic material, and has a hub 21 in the center.
are integrally fixed by bolts (not shown). An input shaft 22 on the transmission side is engaged with the hub 21 via a spline 23, so that the driven member 20 and the input shaft 22 rotate integrally. The hub 21 includes a bearing 26 fixed by circlips 24 and 25, and the bearing 26 supports the driven holder 6 rotatably but not axially.

Inner peripheral surface of drive member 1 and driven member 2
An operating gap 27 is formed between the outer circumferential surface of the magnet 0 and the operating gap 27, and this operating gap 27 is filled with magnetic particles 28. When the magnetic particles 28 are excited by the excitation coil 33, the rotational torque of the drive member 1 is driven by the magnetic attraction force between the magnetic particles 28 and the frictional force between the magnetic particles 28 and the operating surfaces of the drive member 1 and the driven member 20. It is transmitted to the member 20 and rotates both of them together.

The front cover 5 and the rear labyrinth 7 are made of a non-magnetic material such as aluminum, and the front cover 5
and tips 5a and 7a of rear labyrinth 7
are opposed to the inner peripheral surface of the driven member 20. And on the inner peripheral surface of the driven member 20,
Permanent magnets 15 and 16, as shown in detail in FIG. 2, are provided opposite the front end 5a of the front cover and the rear labyrinth end 7a.
The permanent magnets 15 and 16 are preferably rubber magnets, and are annular over the entire inner peripheral surface of the driven member 20. Opposed to these permanent magnets 15 and 16, permanent magnets 6 are also placed at the tip 5a of the front cover and the tip 7a of the labyrinth, respectively.
1,62 are provided. These permanent magnets 6
1 and 62 also have an annular shape over the entire outer peripheral surface of the front cover tip 5a and the labyrinth tip 7a, and are preferably made of rubber magnets.
In this case, the permanent magnets 15 and 16 on the driven member 20 side and the permanent magnets 61 and 62 on the front cover 5 and labyrinth 7 sides face each other with their opposing surfaces having the same magnetic pole. That is, the permanent magnets 15 and 61 have their south poles facing each other, and the permanent magnets 16 and 62 have their north poles facing each other. And these permanent magnets 15, 16
There is a minute gap 15 between the permanent magnets 61 and 62.
a, 16a are secured.

Note that 27a and 27b indicate gaps that are continuous with the operating gap 27 and located on both sides of the operating gap 27.

The operation of the embodiment with such a configuration will be explained.

In FIG. 1, power from the engine is transmitted from the ring gear 10 to the drive member 1 via the crankshaft 11, and therefore the drive member 1
rotates as the engine rotates.

When the electromagnetic coil 3 is energized to generate magnetic flux in the operating gap 27 where the magnetic particles 28 are present, the magnetic particles 2
8 is magnetized, and engine power is transmitted to the driven member 20 by the magnetic coupling force between the magnetic particles and the frictional force between the magnetic particles 28 and the operating surface. Therefore, engine power is transmitted from the hub 21 to the input shaft 22 of the transmission via the spline 23. The coil 3 that generates magnetic flux in the operating gap 27 is supplied with power from the brushes 12, 12 via the slip rings 8, 8, and as a result of current flowing through the coil 3, the yokes 2a, 2
b. A magnetic circuit passing through the operating gap 27 and the driven member 20 is formed to generate magnetic flux. Therefore, depending on the presence or absence of excitation current to the coil 3, it is determined whether rotational torque can be transmitted. When the coil 3 is energized, the magnetic particles 28 are most strongly magnetized within the operating gap 27, but when the energization is cut off, the magnetic particles 28 become open and are pressed against the inner surface of the drive member 1 by centrifugal force, completely disconnecting them. Cut off.

However, when the engine speed is very low or the engine is stopped, the magnetic particles 28 that have fallen off from the operating surface will travel from the operating gap 27 to the nearby gaps 27a and 27b to the front cover 5 and rear labyrinth. It accumulates in each of the recesses 5b and 7b, and further tends to leak out through the gaps 15a and 16a. However, the gap 15a,
Permanent magnets 15, 16 and 61, 62 are attached to the inner circumferential surface of the driven member 20 and the outer circumferential surfaces of the front cover tip 5a and the labyrinth tip 7a, respectively. 61 and 62 are opposed to each other with their opposing surfaces forming the same magnetic pole, so that magnetic fields that repel each other are formed in these gaps 15a and 16a. Therefore, these gaps 15a, 1
The magnetic particles 28 that try to approach the gap 6b are repelled by this magnetic field, and therefore the magnetic particles 28 that try to leak through the gaps 15a and 16a are prevented from passing through, thereby preventing them from leaking, falling off, or scattering. The magnetic particles in the front cover 5 and rear labyrinth 7 near the permanent magnets 15 and 16 are fed into the air gaps 27a and 27b by centrifugal force as the engine rotates at high speed, and returned to the operating air gap 27.

Therefore, according to the above configuration, since the magnetic particles are completely sealed, the magnetic particles can be effectively used for power transmission, and the amount of magnetic particles does not decrease and a high torque transmission ability is maintained over a long period of time. .

Furthermore, the permanent magnets 15 and 16 provided on the inner circumferential surface of the driven member 20 and the permanent magnets 61 and 62 provided on the outer circumferential surfaces of the front cover tip 5a and the labyrinth tip 7a, respectively, are arranged on opposing surfaces. Since these magnets form the same magnetic pole and face each other, a repulsive force is generated between these magnets, and the magnetic particles 28 are repelled and do not adhere to these permanent magnets.
Therefore, the magnetic particles do not collect on these magnets, and problems such as the magnetic particles 28 in the working gap 27 collecting in the gaps 15a and 16a, resulting in insufficient amount of magnetic particles in the working gap 27, are eliminated. This eliminates drag and prevents the generation of gap torque.

Note that when rubber magnets are used as the permanent magnets 15 and 16, it becomes easier to obtain a shape that follows the inner peripheral surface of the driven member 20 and the outer peripheral surfaces of the front cover tip 5a and the labyrinth tip 7a. Assembling is also facilitated since it is possible to use

The permanent magnet of the present invention is not limited to a rubber magnet, but may also be a ferrite magnet, etc.
Furthermore, the means for fixing the magnet is not limited to adhesive, but may also be caulking, screwing, or the like.

Furthermore, the present invention is not limited to installing a permanent magnet between each front end surface of the front cover and rear labyrinth and the driven member 20, but any permanent magnet may be provided between the opposing surfaces of the drive member and the driven member. It can be configured at the minimum separation position except for.

As described in detail above, according to the present invention, at the closest position between the opposing surfaces of the drive member and the driven member, excluding the operating gap, and at two locations sandwiching the operating gap, both sides of these opposing surfaces are provided. An annular permanent magnet is provided on each side, and the opposite poles of these permanent magnets are made the same pole, so that a magnetic field is formed by the annular permanent magnets provided on the opposing surfaces, which prevents magnetic particles from leaking, scattering, or falling off. , it is possible to secure the required amount of magnetic particles within the operating gap. Therefore, magnetic particles can be effectively utilized for torque transmission, and high torque transmission capability can be maintained over a long period of time. Moreover, since the opposing poles of both annular permanent magnets are the same, magnetic particles are discarded by these permanent magnets, and the magnetic particles do not collect in the seal area, which prevents tangling and the generation of air gap torque. be done.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a sectional view of the entire clutch, and FIG. 2 is a sectional view of the main parts. 1... Drive member, 3... Excitation coil, 5
...Front cover, 7...Labyrinth, 20...
...Driven member, 27... Operating gap, 28...
Magnetic powder, 15, 16, 61, 62...Permanent magnet.

Claims (1)

[Claims] 1. A working gap is formed between a drive member which is a driving side rotating body and a driven member which is a driven side rotating body, this working gap is filled with magnetic particles, and the magnetic particles are driven by electromagnetic force. In an electromagnetic powder type clutch that connects and disconnects a drive member and a driven member by being connected to the operating gap, the position where the drive member and the driven member are opposite to each other and the closest position between the two excluding the operating gap is Moreover, an electromagnetic powder type clutch is characterized in that annular permanent magnets are provided on both opposing surfaces at two locations sandwiching the operating gap, and the opposing poles of these permanent magnets are the same.