JPS5828023A - Electromagnetic coupling device - Google Patents

Abstract

PURPOSE:To decrease a decoupling time of an electromagnetic coupling device, by inverting supply voltage to an excitation coil for a very short time immediately before decoupling and removing residual magnetism after decoupling. CONSTITUTION:At decoupling of an electromagnetic coupling device 10, command signals S2, S3 are led out from a control circuit 18 to actuate switching elements 12, 13. Here electromotive force, stored in a coil 15, is absorbed by a varister 16. If this electromotive force becomes lower than power of a DC power source, a reverse excitation current of the electromagnetic coupling device 10 flows from a side of the DC power source to a side of the earth through the switching element 13, coil 15 and switching element 12. That is, in a route for the reverse excitation current to flow, a resistance element is not connected except the coil 15, and power of the DC power source is fully applied to the coil 15, then electromotive force at coupling is absorbed by the varister 16. Accorddingly, the reverse directional excitation current rises earlier.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic coupling device, and more particularly to an electromagnetic coupling bag ff& in an excitation method for speeding up the disconnection time of an electromagnetic coupling device such as a powder clutch.

As is well known, electromagnetic coupling devices are used, for example, in automobile clutches. For this reason, in the electromagnetic coupling device, two methods have been conventionally employed to speed up the disengagement time of the clutch and the like. One method is to install a surge absorption circuit element (for example, a varistor, Zener diode, resistor, capacitor, etc.) in parallel with the coil of the electromagnetic coupling device, and generate a high back electromotive force using a switching element such as a transistor, thereby increasing the excitation current. There is a way to speed up the shutoff time. Another method is to apply a reverse voltage to the coil using switching elements such as four transistors without providing a surge absorbing circuit element, and to apply a reverse excitation current to the coil to cause residual damage to the yoke of the electromagnetic coupling device. There is a way to eliminate magnetism. However, the former method has the disadvantage that the number of surge absorbing circuit elements is limited based on the withstand voltage of a switching element such as a transistor that controls the on/off or excitation current of the electromagnetic coupling device.

In addition, the latter method requires a considerable amount of time until the voltage corresponds to the reverse voltage due to the inductance of the electromagnetic coupling device, and while it is effective for reducing drag torque, it has the disadvantage that the disconnection time is not very quick.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electromagnetic coupling device which is inexpensive and has a simple circuit configuration, and which can shorten the disconnection time.

In summary, this invention is capable of reversing the voltage supplied to the excitation coil in a very short period of time from the time of disconnection to just before disconnection, thereby supplying the back electromotive force necessary to eliminate the residual magnetism after disconnection. This is what I did.

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 are connection circuit state diagrams of an electromagnetic coupling device according to an embodiment of the present invention, in particular, FIG. 1 is when the electromagnetic coupling device is coupled, and the negative S2 diagram is when the electromagnetic coupling device is disconnected. Third
The figure shows the electromagnetic coupling device after the coupling is released.

Although not shown, the electromagnetic coupling device io connects the first coupling portion and the second coupling portion using magnetic particles or the like.

A connecting circuit for connecting or disconnecting the first connecting part and the second connecting part is constructed as shown in FIGS. 1 to 3. In other words, between the - universal polarity and the other polarity of the DC power supply (not shown), in other words, between the DC power supply side and the ground side,
Switching element 11 as an example of first switching means
A series circuit of an excitation coil 15, which is an example of excitation means, and a switching element 14, which is an example of second switching means, is connected. A switching element 13, which is an example of third switching means, is connected in parallel to the series circuit of the switching element 11 and the excitation coil 15. Further, a switching element 12, which is an example of a fourth switching means, is connected in parallel to the series circuit of the switching element 14 and the excitation coil 15.

Further, a varistor 16, which is an example of a surge absorbing means, is connected in parallel to the exciting coil 15. Switching element 13
A resistor 17, which is an example of current control means, is connected in parallel.

Note that the switching elements 11 to 14 may be transistors, thyristors, or electromagnetic relays. The resistor 17 is set so as to obtain the current necessary to eliminate residual magnetism in the electromagnetic coupling device 10.

Next, the operation of this embodiment will be explained with reference to FIGS. 1 to 3. first,? The case where IJ magnetic coupling device 1...']0 is coupled will be explained. In this case, as shown in FIG. 1, the control circuit 8 derives a command signal s1°S4 to activate the switching elements 11, 14. Therefore, the excitation current of the electromagnetic coupling device 10 is transmitted from the DC power supply side to the switching element 11 and the coil 15 as shown by the dotted line in FIG.
, and flows to the ground side via the switching element 14. Therefore, the electromagnetic coupling device 10 connects the first coupling portion and the second coupling portion using the magnetic particles excited by the coil 15.

Next, the case when the electromagnetic coupling device 10 is disconnected will be described. In this case, as shown in Figure i2, the control circuit]8
derives the command signals s2 and s3 and switches the switching element 1
Activate 2.13. At this time, the electromotive force at the time of connection based on the energy stored in the coil 15 (i.e., 1& of the inductance and the square of the excitation current) is the electromotive force of the varistor 16.
absorbed by. The current of this electromotive force flows clockwise as shown by the dashed line in FIG. This electromotive force is DC 1
When the power becomes lower than 1i, the reverse excitation current of the electromagnetic coupling device 10 flows from the DC power supply side to the ground side via the switching element 13, the coil 15, and the switching element 12, as shown by the dotted line in FIG. That is, since no resistance element is connected to the path through which the reverse excitation current of the electromagnetic coupling device 10 flows, except for the coil 15, the DC power is directly applied to the coil 5, and the electromotive force at the time of coupling is reduced by the varistor 16. , the excitation current in the opposite direction rises earlier than in the conventional electromagnetic connection bag FIF. Therefore, the electromagnetic coupling device 10 uses the coil 15 to quickly release the coupling state between the first coupling portion and the second coupling portion.

Furthermore, a case after the electromagnetic coupling device 10 is disconnected will be described. In this case, the control circuit 18 as shown in FIG.
derives only the command signal S2 and activates the switching element 12. Therefore, the reverse excitation current of the ia magnetic coupling device
7, the coil 15, and the switching element 12 to the ground side. This resistor 17 is set so as to obtain the current necessary to eliminate the residual magnetism of the magnetic particles of the electromagnetic coupling device 10, the first coupling portion, and the second coupling portion.

For this reason, the first problem is due to residual magnetism. The rotating torque becomes smaller.

In the above embodiment, the electromagnetic coupling device is described as a clutch, but the present invention is not limited to this. Either the first coupling portion or the second coupling portion may be fixed and used as a brake. Also good.

As described above, according to the present invention, a coil and a varistor are connected in parallel, and a resistor is connected between the DC power supply side and the coil to erase the residual magnetism of the electromagnetic coupling device after the connection is released. As a result, the cost can be reduced and the disconnection time can be shortened with a simple circuit configuration.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 show circuit diagrams of an electromagnetic coupling device according to an embodiment of the present invention when the electromagnetic coupling device is coupled, when the coupling is released, and after the coupling is released. In the figure, 10 is an electromagnetic coupling device, 11 to 14 are switching elements, 15 is an exciting coil, 16 is a varistor, and 17
indicates a resistor, and 18 indicates a control circuit. Agent Shin Kuzuno - (1 other person) Figure 1 Figure 2 Figure 3

Claims (1)

Claims: An electromagnetic coupling device that connects the first coupling part and the second coupling part by magnetizing magnetic particles sealed between the first coupling part and the second coupling part, excitation means for magnetizing the magnetic particles and connecting the first connection part and the second connection part; a first switching means connected between the excitation means and one polarity of the power supply; the excitation; a second switching means connected between the excitation means and the other polarity of the power supply;
a third switching means connected in parallel to the switching means; a fourth switching means connected in parallel to the excitation means and the second switching means; a fourth switching means connected in parallel with the excitation means, and surge absorbing means for absorbing the electromotive force of the excitation means when the electromagnetic coupling device is coupled when the electromagnetic coupling device is disconnected; current control means having an impedance element capable of flowing a current necessary to eliminate residual energy in the electromagnetic coupling device; and a current control means having an impedance element capable of flowing a current necessary to eliminate residual energy in the electromagnetic coupling device, and switching between the first switching means and the second switching device when the electromagnetic coupling device is in a coupling mode. activate the means,
control for activating the third switching means and the fourth switching means in a "during-uncoupling mode" of the electromagnetic coupling device, and activating the fourth switching means in a "post-coupling mode" of the electromagnetic coupling device; An electromagnetic coupling device comprising means.