JPH06101960B2 - Control circuit of electromagnetic coupling device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control circuit for releasing an erroneous attraction of an electromagnetic coupling device including a permanent magnet.

[Conventional technology]

In electromagnetic coupling devices such as electromagnetic clutches and brakes, energization to the exciting coil is continued while the coupling state is maintained, but continuing energization is uneconomical because of large power consumption. Therefore, it is provided to face the member for adsorbing the permanent magnet via a predetermined gap, and the magnetic flux generated by this permanent magnet and the current in the direction of generating the magnetic flux in the assisting direction and the canceling direction are passed to the exciting coils for a short time, A method of adsorbing the adsorption member by generating magnetic flux in the assisting direction and holding the coupling state by the magnetic flux of the permanent magnet, while canceling the magnetic flux of the permanent magnet by generating magnetic flux in the canceling direction and releasing the coupling state. Has been recently developed, and the details thereof are presented in a separate application of the present applicant.

[Problems to be solved by the invention]

However, the facing gap between the attracting member and the permanent magnet is often small, and in this case, the member is permanently resisted against the bias of a leaf spring or the like that maintains the gap due to external impact or vibration. There is a problem that the magnet is erroneously attracted to the magnet and an unexpected connection state occurs.

[Means for solving problems]

In order to solve the above problems, the present invention is configured by the following means.

That is, in the control circuit for the above-mentioned electromagnetic coupling device, the induced voltage induced in the exciting coil is compared with the reference voltage, and a comparator that produces a comparison output when the induced voltage becomes equal to or higher than the reference voltage, A comparison operation prohibition means for giving a comparison operation prohibition command to the comparator when the coil is energized, and a pulse generator for generating a pulse for passing a current in a direction to generate a magnetic flux in a canceling direction to the exciting coil according to the comparison output generated by the comparator. Is provided.

[Action]

Therefore, when the excitation coil acts as a detection coil and the attracted member erroneously attracts, based on the change in the amount of magnetic flux due to the permanent magnet that responds to the decrease in the magnetic resistance of the magnetic path,
Since an induced voltage is generated in the exciting coil, this is detected by the comparator, and the pulse generator generates a pulse with a predetermined time width, which causes a current in the direction that creates a magnetic flux in the canceling direction to flow in the exciting coil, resulting in erroneous adsorption. The state is released immediately and automatically.

〔Example〕

Hereinafter, the details of the present invention will be described with reference to the drawings illustrating examples.

FIG. 2 is a cross-sectional view showing an electromagnetic clutch as an electromagnetic coupling device, in which a cylindrical member 4 is rotatably supported by a bearing 3 fixed to a housing 2 via a bearing holder 1, and this cross section has a substantially rectangular shape. A permanent magnet 7 held by a pair of magnetic plates 5 and 6 holds the magnetic plates 5 and 6 in a flange 4 of the cylindrical member 4 in an annular groove of the cylindrical member 4 having a V shape.
It is installed by being fixed to a and 4b.

Further, in the annular groove of the cylindrical member 4, the opening side of the field core 9 in which the exciting coil 10 is provided is partially inserted and arranged, and the cylindrical member 4 and the field core 9 are connected to each other. Bearing holder 1, Bearing 3, Washer 17a,
The nut 17b is concentrically integrated to form an exciting device.

On the other hand, a rotating member having an armature 11 as a member to be attracted which faces the exciting device through a predetermined gap in the axial direction, is provided with respect to an armature hub 14 axially mounted on the rotating shaft 13 concentric with the exciting device. The armature 11 is movably supported in the axial direction via a leaf spring 12.

Therefore, if an electric current is passed through the exciting coil 10 as a direction in which the magnetic flux generated by the permanent magnet 7 and the magnetic flux in the assisting direction are obtained, the generated magnetic flux causes the armature 11
Is attracted to the exciter against the restoring force of the leaf spring 12, and this magnetically attracted state is maintained by the magnetic flux generated by the permanent magnet 7.

On the other hand, when a reverse current is passed through the exciting coil 10,
Due to this, the magnetic flux generated and the magnetic flux of the permanent magnet 7 are offset, and the armature 11 is separated from the exciter by the restoring force of the leaf spring 12, and the connected state is released.

In this case, the cylindrical member 4 of the exciting device is configured to be rotatable and serves as an electromagnetic clutch, but when the cylindrical member 4 is fixed, it serves as an electromagnetic brake.

FIG. 1 is a block diagram, in which a surge absorber 101 such as a varistor is connected in parallel with the exciting coil 10 and switches 102, 10 for passing a current from the power source E ₁ to E ₂ .
3 and switches 104 and 105 for passing a current in the opposite direction are connected. When the switches 102 and 103 are turned on, the magnetic flux generated by the permanent magnet 7 and the magnetic flux in the assisting direction are generated by the exciting coil 10, and the armature 11 is attracted to the connected state. While becoming
When the switches 104 and 105 are turned on, the magnetic flux generated by the permanent magnet 7 and the magnetic flux in the canceling direction are generated by the exciting coil 10, and the armature 11 is released to release the connected state.

The terminal voltage of the exciting coil 10 is amplified by the amplifier 106 and then given to the comparator 107, where the voltage source 1
Compared with the reference voltage of 08, the amplifier 10
When the output voltage of 6 becomes equal to or higher than the reference voltage, the comparator 107 produces a comparison output, which drives the pulse generator 109 such as a monostable multivibrator to generate a pulse of a predetermined width. In response to this, the release command unit 110 turns on the switches 104 and 105 for a predetermined time via the drive circuit 111, and the excitation coil 1
The current in the direction of generating a magnetic flux in a canceling direction with the magnetic flux of the permanent magnet 7 is passed to 0.

However, the comparator 107 is designed to perform a comparison operation in response to a command from the control unit 112, the control unit 112 controls the suction command unit 113, and the switches 102, 10 are driven via the drive circuit 114.
While the switch 3 is turned on for a certain period of time, or the control unit 112 controls the release command unit 110, the switch 10 is switched via the drive circuit 111.
While 4,105 is turned on for a predetermined time, the control unit 112 gives a comparison operation prohibition command to the comparator 107, and the comparator 107 does not generate a comparison output due to the terminal voltage of the exciting coil 10 due to energization.

For this reason, the comparator 107 has switches 102, 103 or 104, 105.
The comparison operation is not performed during energization by turning on, and the comparison operation is performed only during non-energization.If the armature unit 11 does not erroneously adsorb due to external shock or vibration when the connection is released, The amount of magnetic flux by the permanent magnet 8 changes due to the decrease in the magnetic resistance of the magnetic path, and the voltage is excited in the exciting coil 10 according to this change, and the induced voltage via the amplifier 106 becomes equal to or higher than the reference voltage.
109 generates a pulse, and accordingly switch 104,1
05 is turned on for a predetermined time, the connection state due to erroneous adsorption is immediately released, and unexpected connection state occurrence due to continuation of erroneous adsorption is prevented.

The comparison operation prohibition command that the control unit 112 gives to the comparator 107 when the exciting coil 10 is energized is the switch 102, 103 or 10
It should be started immediately before turning on the 4,105, and should be finished in about 10 msec after turning off each switch, and the terminal voltage and surge voltage due to the turning on and off of each switch should not be detected. , A slight induced voltage is generated even in response to the slight vibration of the armature 11,
The reference voltage of the voltage source 108 may be set higher than the voltage corresponding thereto and lower than the voltage corresponding to the erroneous adsorption of the armature 11.

Further, the release command unit 110 and the suction command unit 113 include a control circuit 112.
According to the above control, a pulse generator that generates a pulse of each time width required for releasing and adsorbing the armature 11 may be used, and an equivalent pulse generator 109 may be used.

It should be noted that the switches 102 to 105 use mechanical contacts or semiconductor switching elements, etc., and drive circuits 111, 11 are correspondingly used.
The configuration of 4 should be defined.

Therefore, even if erroneous adsorption of the armature 11 is caused, the adsorption state is immediately and automatically released, the unexpected connection state is reliably prevented, and the exciting coil 10 is shared with the detection coil. The objective can be sufficiently achieved by a simple and inexpensive structure in which only some circuits are added.

However, depending on the ON period of the switches 102 to 105, the comparator 10
In order to prohibit the comparison operation of 7, finally the pulse generator 109
It does not matter if the pulse generator 109 does not send a pulse, and it is the same even if a gate circuit or a switching circuit is inserted on the input side or the output side of the pulse generator 109 and it is turned off by an operation prohibition command. And release command unit 110
Alternatively, a differentiating circuit may be inserted on the output side of the comparator 107 and then combined with the control output of the control unit 112 by an OR gate or the like to be given, and the control unit 112 to each command unit 11
Various modifications are possible, such as configuring 0, 113 with a microprocessor or the like is optional.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, the accidental attraction of the electromagnetically coupled device provided with the permanent magnet is immediately and automatically released by the simple and inexpensive structure, and the accidental attraction of the attracted member is caused. Since the occurrence of the state is reliably prevented, a remarkable effect can be obtained in the control circuit applied to various electromagnetic coupling devices including permanent magnets.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a block diagram, and FIG.
The figure is a cross-sectional view of an electromagnetic clutch. 7 ... permanent magnet, 10 ... excitation coil, 11 ... armature, 102-105 ... switch, 107 ... comparator, 108 ... voltage source, 109 ... pulse generator, 110 ... release command section, 111,
114 ... Drive circuit, 112 ... Control part, 113 ... Adsorption command part.

Claims (1)

[Claims] 1. A permanent magnet provided through a predetermined gap from a member to be attracted, and an exciting coil in which a magnetic flux generated by the permanent magnet and a current generating a magnetic flux in an assisting direction and a canceling direction are supplied to each of them. A control circuit of an electromagnetic coupling device including: a comparator that compares an induced voltage induced in the exciting coil with a reference voltage, and generates a comparison output when the induced voltage is equal to or higher than the reference voltage; A comparison operation prohibiting means for giving a comparison operation prohibition command to the comparator when the current is energized, and a pulse for generating a pulse for passing a current in the direction of generating the magnetic flux in the canceling direction to the exciting coil in accordance with the comparison output generated by the comparator. A control circuit for an electromagnetic coupling device, comprising a generator.