JPH0544739A - Torque control device for electromagnetic clutch and electromagnetic brake - Google Patents

Abstract

PURPOSE:To reduce electric power loss and exhibit maximum capacity in a light weighted torque control device by making a pulse train with a bridge type switching circuit after converting alternating current to direct current with a rectifier circuit, so as to control voltage and current supplied to an electromagnetic clutch or an electromagnetic brake. CONSTITUTION:This device is set by inputting operating condition from an operation panel 17. A pulse train having previously set period and duty ratio according to the set current command value is made with a PWM circuit 15. By the pulse of the pulse train, a drive transistor 26 is ON, current is supplied from a direct current power source 25 to a drive transformer 28, and a first switching transistor 23 is ON. The voltage of a plus power supply bus line (e) is raised with a control circuit 16 through a switch circuit 11 and a rectifier circuit 10. Then, by ON of the switching transistor 23, current is supplied from the plus power supply bus line (e) to a minus power supply bus line (f). When this pulse is cut off, the drive transistor 26 is OFF and accumulated energy is recovered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention supplies a predetermined drive torque to a load mechanism device or a predetermined brake torque from a mechanism having a driving force, which is used in various mechanical devices that start and stop relatively frequently. The present invention relates to a torque control device for absorbing an electromagnetic clutch and an electromagnetic brake. In particular, the function of the electromagnetic clutch and the electromagnetic brake can be effectively exhibited by supplying an overexciting current at the start of operation, and the operation of the electromagnetic clutch and the electromagnetic brake can be performed. The present invention relates to a torque control device for an electromagnetic clutch and an electromagnetic brake, which is capable of accurately controlling an appropriate torque or a braking torque without fear of mutual interference, and has a small loss.

[0002]

2. Description of the Related Art A controllable electromagnetic clutch is used as shown in FIG. 4 to supply a predetermined drive torque to a load mechanism device, and a controllable electromagnetic clutch can be controlled to absorb a predetermined brake torque from a mechanism having a driving force. An electromagnetic brake is used as shown in FIG. That is, in FIG. 4, for example, an output shaft a from a motor 1 which is a driving power source is connected to an input shaft of an electromagnetic clutch 2, and an output shaft of the electromagnetic clutch 2 is connected to an input shaft b of a predetermined load mechanism 3. Has been done. The electromagnetic clutch 2 is driven by a current supplied from a power supply device 5 having a control function of converting the AC power supply 4 into a current of a predetermined magnitude. Therefore, the torque supplied from the electric motor 1 to the load mechanism 3 is controlled to a desired value by the current value output from the power supply device 5 and supplied to the exciting coil of the electromagnetic clutch 2.

In FIG. 5, the output shaft c of the mechanical device 6 having a driving function is connected to the input shaft of the electromagnetic brake 7, and the fixed shaft of the electromagnetic brake 7 is connected to the shaft part d of the fixed portion 9. There is. The electromagnetic brake described above has a power supply device 5 having a control function of converting the AC power supply 4 into a current of a predetermined magnitude.
It is driven so as to absorb a desired brake torque by a current supplied from the. Therefore, the power supply device 5
The brake torque absorbed from the output shaft of the mechanical device 6 having a drive function is controlled to a desired value by the current value output from the motor and supplied to the exciting coil of the electromagnetic brake 7. In order to speed up the rising speed of the electromagnetic clutch / brake (hereinafter abbreviated as electromagnetic clutch / brake) when the electromagnetic clutch or brake as described above is activated, an overexcitation current is passed through the electromagnetic clutch / brake.

As described above, a conventional power supply device having a control function of causing an overexciting current to flow through the electromagnetic clutch / brake in order to increase the rising speed of the electromagnetic clutch / brake (hereinafter abbreviated as a control device). 5 is configured, for example, as shown in FIG. That is, in FIG. 7, the AC power supply 4 is converted into a predetermined voltage by the power supply transformer 40, and further converted into, for example, 90 V DC by the rectifier circuit 41 and the filtering capacitor 42. This DC voltage is supplied to the exciting coil of the electromagnetic clutch / brake 8 when the switching transistor 43 controlled by the command signal from the control device 45 is turned on. Further, the AC power supply 4 is converted into a predetermined voltage by the power supply transformer 50, and further converted into, for example, 24 V DC by the rectifying circuit 51 and the filtering capacitor 52. This DC voltage is supplied to the exciting coil of the electromagnetic clutch / brake 8 when the switching transistor 53 controlled by the command signal from the control device 45 becomes conductive. When the electromagnetic clutch / brake 8 is activated, the switching transistor 43 is turned on to apply a voltage of 90 V to the electromagnetic clutch / brake 8. Therefore, an overcurrent flows in the exciting coil of the electromagnetic clutch / brake and the electromagnetic clutch / brake operates rapidly. After the operation of the electromagnetic clutch / brake 8 is started, the switch transistor 43 is turned off and the transistor 53 is turned on so that the electromagnetic clutch / brake 8 is not burned or its life is shortened. The voltage applied to the clutch / brake 8 is switched from 90 volts to 24 volts. Therefore, this electromagnetic clutch / brake performs the desired operation.

[0005]

By the way, according to the electromagnetic clutch / brake control device as described above, it is necessary to provide two kinds of power supplies for supplying to the electromagnetic clutch / brake, and therefore two power supplies are required. Power transformer 4
The size of 0,50 is large and the weight is heavy. The voltage to be supplied to the electromagnetic clutch / brake can be switched between two types, but the voltage cannot be adjusted. Depending on the conditions of the load mechanism device, it may be effective to mount both the electromagnetic clutch and the electromagnetic brake as shown in FIG. That is, in FIG. 6, for example, the output shaft a from the electric motor 1 which is a driving power source is the electromagnetic clutch 2
Is connected to the input shaft of the electromagnetic clutch 2 and the output shaft of the electromagnetic clutch 2 is connected to the input shaft b of the predetermined load mechanism 3. The electromagnetic clutch 3 described above is driven by a current supplied from the control device 5a that converts the AC power supply 4 into a current of a predetermined magnitude. The output shaft c of the load mechanism 3 is connected to the electromagnetic brake 7
Of the electromagnetic brake 7, and the fixed shaft of the electromagnetic brake 7 is connected to the shaft portion d of the fixed portion 9. The electromagnetic brake described above is driven so as to absorb a desired brake torque by the current supplied from the power supply device 5b having a control function of converting the AC power supply 4 into a current of a predetermined magnitude.
In the case of the above-mentioned structure, it is difficult to control the operation of the electromagnetic clutch and the electromagnetic brake at high speed without interfering with each other and without delay. The present invention is capable of effectively exerting the maximum capacity of an electromagnetic clutch and / or an electromagnetic brake as a countermeasure for the above-mentioned conventional problems, is light in weight and has little power loss, and a torque control device for the electromagnetic clutch and the electromagnetic brake. The challenge is to obtain.

[0006]

In order to solve the above-mentioned problems, a torque control device for an electromagnetic clutch and an electromagnetic brake according to the present invention converts an AC power supply into a DC current by a rectifying circuit and then converts it into a pulse train by a bridge type switching circuit. To supply the electromagnetic clutch or electromagnetic brake. The switching operation of this switching circuit is operated by a predetermined setting signal that defines the torque to be supplied by the electromagnetic clutch or the torque to be absorbed by the electromagnetic brake. Further, the timing of supplying voltage or current to the electromagnetic clutch or brake is adapted to the operating status of the device including the electromagnetic clutch or brake. In the control described above, an overexciting current is supplied for a predetermined time at the start of operation of the electromagnetic clutch or electromagnetic brake, and
It is effective to stop the excitation current supply for a predetermined time when the operation of the electromagnetic clutch or the electromagnetic brake is completed. The voltage value applied to the electromagnetic clutch or the electromagnetic brake or the current value flowing through the electromagnetic clutch or the electromagnetic brake is detected and compared with the above setting signal to correct the operation of the switching circuit. It is effective to use a half bridge type for the above-mentioned bridge type switching circuit, and it is effective to use a PWM circuit for the pulse train generating circuit that operates the switching circuit. Further, it is effective that the rectifier circuit for converting the AC power supply into DC is capable of outputting at least two kinds of different DC voltages.

[0007]

With the configuration described above, the effective voltage of the voltage to be supplied to the electromagnetic clutch or brake is set by appropriately setting the cycle and duty ratio of the pulse train converted from direct current by the switch operation of the bridge type switching circuit. The value or the effective value of the current (the description of the effective value is omitted below) can be freely controlled. Therefore, when the electromagnetic clutch or electromagnetic brake is activated, an overexciting current is allowed to flow for a predetermined time, and after the electromagnetic clutch or electromagnetic brake has started to operate, an appropriate value of exciting current is allowed to flow and the electromagnetic clutch should transmit. The torque having a desired magnitude or the brake torque to be absorbed by the electromagnetic brake can be freely controlled. In addition, when the switching operation in the switching circuit and the timing at which a predetermined current is supplied to the electromagnetic clutch or the electromagnetic brake are activated by predetermined setting signals, in particular, when an overexciting current is supplied for a predetermined time at startup, the startup characteristics It is improved, and this over-exciting current does not flow for a long time to burn or deteriorate the electromagnetic clutch or brake. Further, if the exciting current supply is stopped for a predetermined time when the operation of the electromagnetic clutch or the electromagnetic brake is terminated, the operation of the electromagnetic clutch and the electromagnetic brake can be interlocked so as not to affect each other. Further, there is no possibility that the semiconductor or the like will be damaged or malfunction due to noise due to overvoltage generated by making the circuit non-conductive. Further, since the voltage value or the flowing current value applied to the electromagnetic clutch or electromagnetic brake is detected and compared with the above setting signal to correct the control of the switching circuit, the characteristics of this electromagnetic clutch or electromagnetic brake are adjusted in advance. Torque to be transmitted by the electromagnetic clutch by setting the setting signal indicating the corresponding voltage value or current value to indicate the torque to be transmitted by the electromagnetic clutch or the brake torque to be absorbed by the electromagnetic brake. Alternatively, the brake torque to be absorbed by the electromagnetic brake can be freely controlled. Further, since the torque control device for the electromagnetic clutch and the electromagnetic brake according to the present invention obtains the desired torque by switching as described above, the circuit frequency can be set to a high frequency, so that the transformer is lightweight and compact. By using the half bridge type for the switching circuit described above, a torque control device for an electromagnetic clutch / brake that is optimal for a normal large electromagnetic clutch / brake that allows a current of about 10 amperes to be obtained can be obtained. Further, by using the PWM circuit in the pulse train generating circuit that operates the switching circuit, the pulse train that operates the switching circuit can be easily obtained with high accuracy corresponding to the torque value desired for the electromagnetic clutch / brake. Further, when the rectifier circuit for converting the AC power supply into DC is capable of outputting at least two kinds of different DC voltages, the overexcitation current can be effectively created. On the contrary, the torque control device for the electromagnetic clutch and the electromagnetic brake can be used in any place where different AC voltage power supplies are supplied.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a torque control device for an electromagnetic clutch and an electromagnetic brake according to the present invention is applied to a device including an electromagnetic clutch and an electromagnetic brake, which are problems in FIG. , FIG. 3 will be described. FIG. 1 shows a circuit configuration of an embodiment of a torque control device for an electromagnetic clutch and an electromagnetic brake, and FIG. 2 is an electromagnetic clutch or an electromagnetic powder clutch which is a kind of an electromagnetic brake and is suitable for applying the present invention. Or it indicates an electromagnetic powder brake. In addition, in FIG.
5 shows an example of timing during operation according to the present invention. Since the basic structures of the electromagnetic powder clutch and the electromagnetic powder brake can be explained in common, they will be referred to as the electromagnetic powder clutch / brake hereinafter. Although there are various types of electromagnetic powder clutch / brake structures, FIG. 2 symbolically shows a cross section along the rotation axis of the diameter part of the basic structure of one type of electromagnetic powder clutch / brake. ..

In FIG. 2, reference numeral 8 denotes an electromagnetic powder clutch / brake, which is a donut-shaped fixed exciting core 8
An exciting coil 82 is provided inside the unit 1. Reference numeral 83 is a cylinder made of a magnetic material, leaving a part of the portion facing the exciting coil, and is connected to the input shaft 84. Further, 85 is a driven roller, which is connected to the output shaft 86. A magnetic powder (not shown) is enclosed in a space 87 between the cylinder 83 and the driven roller 85. As shown in FIG. 6, the input shaft 84 of the electromagnetic powder clutch / brake 8 having the above-described structure is coupled to the output shaft a of the driving power source 1 as the electromagnetic powder clutch 2, and the output shaft of the electromagnetic powder clutch 2 (see FIG. 2 is coupled to the input shaft b of the load mechanism 3 and no exciting current is supplied to the exciting coil 82 as shown in FIG. Since the magnetic powder is rotated by the source 1, the magnetic powder (not shown) enclosed in the space 87 is rotated by the centrifugal force accompanying the rotation of the cylinder 83 along the cylinder 83 wall in the space 87 according to the rotation of the cylinder 83. Since there is no coupling function between the cylinder 83 and the driven roller 85, the driven roller 8
The rotational force is not transmitted to 5 and the output shaft 86 does not rotate. Therefore, the rotational torque of the driving power source 1 is not transmitted to the load mechanism 3. When a current of a predetermined magnitude is applied to the exciting coil in the above-described state, the magnetic flux φ generated by this current causes the exciting core 81, the cylinder 83, the driven roller 85, the cylinder 83, and the exciting core 81 to move as shown in FIG. Bring to reflux. Therefore, the magnetic powder (not shown) sealed in the space 87 is attracted to the P portion by the attractive force of the magnetic flux φ. Therefore, the driven roller 85 rotates according to the rotation of the cylinder 83 by the attraction force via the magnetic powder of the P section. The attraction force described above changes depending on the value of the current flowing through the exciting coil 82. Therefore, the torque transmitted by the electromagnetic powder clutch 2 shown in FIG. 6 is controlled by the current supplied to the exciting coil 82.

As shown in FIG. 6, the input shaft 84 of the electromagnetic powder clutch / brake 8 having the above-mentioned structure is connected to the output shaft c of the load mechanism 3 as the electromagnetic powder brake 7, and the output shaft of the electromagnetic powder brake 7 (see FIG. 2 is coupled to the coupling shaft d of the fixed portion 9, and when the exciting current is not supplied to the exciting coil 82 shown in FIG. 2, the cylinder 83 coupled to the input shaft 84 has a driving function. Since it is rotated by the mechanical device 6 having
The magnetic powder (not shown) enclosed in 7 rotates with the rotation of the cylinder 83 along the wall of the cylinder 83 in the space 87 by the centrifugal force accompanying the rotation of the cylinder 83. Since there is no coupling function between the cylinder 83 and the driven roller 85, the electromagnetic powder clutch / brake 8 does not function as a brake even if the output shaft 86 is fixed. When a current of a predetermined magnitude is applied to the exciting coil in the above-described state, the magnetic flux φ generated by this current causes the exciting core 81, the cylinder 83, the driven roller 85, the cylinder 83, and the exciting core 81 to move as shown in FIG. Bring to reflux. Therefore, the magnetic powder (not shown) sealed in the space 87 is attracted to the P portion by the attractive force of the magnetic flux φ. Therefore, the driven roller 85 connected to the fixed portion 9 by the attraction force via the magnetic powder of the P portion functions as a brake for the cylinder 83. The attraction force described above changes depending on the value of the current flowing through the exciting coil 82. Therefore, the brake torque absorbed by the electromagnetic powder brake 7 shown in FIG.
2 controlled by the current supplied to it.

Next, referring to FIG. 1, a detailed description will be given of an embodiment of a torque control device for an electromagnetic clutch and an electromagnetic brake according to the present invention, which is applied to the combined control of the electromagnetic powder clutch and the brake described above with reference to FIG. .. FIG. 1 is a simplified view of main components for explaining the present invention, and detailed component parts such as a power supply circuit and a ground circuit and wiring are not shown. Also, snubber circuits, etc.
A circuit for element protection and noise elimination, and an auxiliary circuit for improving the stability and efficiency of the circuit are not shown. Further, the reference numerals of the common element circuit parts shown in the drawings of the conventional embodiment are commonly used. In FIG. 1, reference numeral 4 is an AC power supply supplied from an AC power supply bus, and the AC power supplied from this AC power supply is the switching circuit 1
A first rectifier circuit 10 having a switchable bridge-type rectifier circuit and a double voltage rectifier circuit converts the direct current supplied between the positive power source bus e and the negative power source bus f. This direct current is applied to the switching circuit 12
Is converted into a predetermined pulse train whose details will be described later.
The pulse train converted by the switching circuit 12 becomes a direct current by the second rectifier circuit 13 and is supplied to the electromagnetic powder clutch 2 or the electromagnetic powder brake 7. The switching circuit 12 is operated by a pulse train creating circuit 15, for example, a pulse train having a predetermined cycle and duty ratio created by a PWM circuit (hereinafter referred to as a PWM circuit). The switching circuit 12 includes capacitors 21, 22 and switching transistors 23, 24.
Is a half-bridge type switching circuit configured by. The first drive transistor 26, which is turned on and off by the pulse train having a predetermined cycle and duty ratio created by the PWM circuit 15, interrupts the DC voltage 25, for example, plus 15 V, to drive the first drive transformer 2
The base of the first switching transistor 23 is driven via 8. The primary winding of the first drive transformer 28 is also grounded by the first diode 27. Further, the second drive transistor 29 which is turned on and off by the pulse train having the predetermined cycle and the duty ratio created by the PWM circuit 15 connects and disconnects the DC voltage 25 described above at a timing different from that of the first drive transistor 26. , Drives the base of the second switching transistor 24 via the second drive transformer 31. The primary winding of the second drive transformer 31 is also grounded by the second diode 30.

Between the connection points of the capacitors 21 and 22 and the switching transistors 23 and 24, which form a bridge circuit connected between the positive and negative power supply buses e and f, and the connection points of the switching transistors 23 and 24, the primary of the switching transformer 32 is provided. The side winding 32a is connected. Switching transistor 2
When 3 and 24 are respectively driven, a current flows between the positive power supply bus e and the negative power supply bus f, which changes direction in the primary winding 32a of the switching transformer 32 and intermittently flows. Therefore, 2 of the switching transformer 32
A pulse current in both directions is output from the secondary winding 32b at a level according to the winding ratio. In the second rectifier circuit 13, the output of the center tap type secondary winding 32b of the switching transformer 32 is double-wave rectified by a pair of rectifying diodes 33 and 34, and the electromagnetic powder clutch 2 or the electromagnetic powder brake 7 is rectified. Supply to. The current is determined by whether the first switch transistor 35 connected in series to the electromagnetic powder clutch 2 or the second switch transistor 36 connected in series to the electromagnetic powder brake 7 is conductive or non-conductive. The switch transistor 35 and the second switch transistor 36 are controlled by a control signal from the control circuit 16 whose details will be described later. Electromagnetic powder clutch 2 or electromagnetic powder brake 7
The electric current flowing through is detected by a resistor 37 for electromagnetic powder clutch / brake current detection connected in series and is supplied to the PWM circuit 15. The PWM circuit 15 also includes exciting coils for each of the electromagnetic powder clutch 2 and the electromagnetic powder brake 7 (reference numeral 8 shown in FIG. 2).
2) Timing and magnitude of current to be supplied to, that is, P
A signal for controlling the timing at which the WM circuit 15 outputs the pulse train, the duty ratio of the pulse train, and, if necessary, the cycle of the pulse train is input from the control circuit 16. The operating conditions for realizing the above-mentioned functions, which the control circuit 16 has in its circuit, are set by an operation panel 17 which is a setting means, and a mechanical device provided with the electromagnetic powder clutch 2 and the electromagnetic powder brake 7 is set. Are sequentially controlled by a control signal 18 output from a higher-level control device (not shown). The operating torque set value input to the operation panel 17 is the exciting current versus operating torque characteristic of the electromagnetic powder clutch 2 and the electromagnetic powder brake 7, respectively.
It is set as an appropriate current command value corresponding to the characteristics of the switching circuit 12 and the signal value indicating the current of the electromagnetic powder clutch / brake detected by the resistor 35 for detecting the electromagnetic powder clutch / brake current. .. The timing set values that are input to the operation panel 17 and determine the above-mentioned operation timings of the electromagnetic powder clutch or the electromagnetic powder brake are the rising characteristics at startup of the electromagnetic powder clutch 2 and the electromagnetic powder brake 7, and the electromagnetic powder clutch 2 respectively. It also corresponds to the accumulated energy absorption time of each circuit including the electromagnetic powder clutch 2 or the electromagnetic powder brake 7 when the electromagnetic powder brake 7 is deactivated, that is, the time characteristic until the circuit current decays to a predetermined value. Is set as an appropriate timing command value determined by

Next, the operation of the above-mentioned circuit configuration will be described. The main operating conditions of the electromagnetic clutch 2 and the electromagnetic brake 7 are set and input from an operation panel 17 provided as a setting means by confirming the measurement when the electromagnetic clutch 2 and the electromagnetic brake 7 are installed in a higher-level machine. That is, each exciting current value determined by the transmission torque value of the electromagnetic powder clutch 2, the braking torque value to be absorbed by the electromagnetic powder brake 7, the overexciting current value to be supplied when the electromagnetic powder clutch 2 is started, and the required overexcitation time, Also, even after the power supply from the switching circuit 12 is stopped, the pulse voltage generated by the stored energy is safe even if the current circulating in the circuit of the electromagnetic powder clutch 2 cuts off the conduction of the switch transistor 35. Time to reach a certain value,
Also, the overexcitation current value to be supplied when the electromagnetic powder brake 7 is started and the required overexcitation time, and the current flowing through the circuit of the electromagnetic powder brake 7 after the power supply from the switching circuit 12 is stopped, Even when the conduction of the switch transistor 36 is cut off, the time until the pulse voltage regenerated by the accumulated energy reaches a safe value is set. The pulse width changes in proportion to the magnitude of the set excitation current value, that is, the pulse train having the preset cycle and duty ratio corresponding to this current command value is PW.
It is created by the M circuit 15. The pulse of this pulse train is the first
When the first driving transistor 26 is turned on by inputting it to the driving transistor 26 of
A current is caused to flow through the primary winding of the drive transformer 28, and the gate of the first switching transistor 23 is driven via this first drive transformer 28 to be turned on. Further, the control circuit 16 outputs a control signal to the switch circuit 11 to make the rectifier circuit a voltage doubler rectifier circuit and increase the voltage of the positive power supply bus e. When the first switching transistor 23 is turned on, a current flows from the positive power source bus e through the first switching transistor 23, the primary winding 32a of the switching transformer 32, and the second capacitor 22 to the negative power source bus f. When this pulse is cut off, the first drive transistor 26 is turned off, and the energy accumulated in the drive circuit while the first switching transistor 23 is on is promptly recovered by the first diode 27. After the first driving transistor 26 is turned off, the PWM circuit 15 then operates the second driving transistor 2
The pulse is input to the second driving transistor 29
Turn on. Therefore, by the same function as described above, the second
Switching transistor 24 is turned on. When the second switching transistor 24 is turned on, a current flows from the positive power source bus line e to the negative power source bus line f through the first capacitor 21, the primary winding 32a of the switching transformer 32, and the second switching transistor 24.
When this pulse is cut off, the second drive transistor 29 is turned off, and the energy accumulated in the drive circuit while the second switching transistor 24 is on is promptly recovered by the second diode 30. After that, the above-mentioned operation is repeated. Therefore, the pulse train causes a current to flow in the switching transformer 32 in alternating directions, and transmits the pulse power to the secondary winding 32b of the switching transformer 32. The pulse power output to the secondary winding 32b of the switching transformer 32 is the rectifying diode 3
Both waves are rectified by 3, 34. In the above process, when the switch transistor 35 is turned on by the signal from the control circuit 16, the rectifying diode 33,
The current that has undergone both-wave rectification by 34 flows into the exciting coil of the electromagnetic powder clutch 2 to rapidly operate the electromagnetic powder clutch 2. When the switch transistor 36 is in the conductive state by the signal from the control circuit 16, the current rectified by both waves by the rectifying diodes 33 and 34 flows into the exciting coil of the electromagnetic powder brake 7 to rapidly activate the electromagnetic powder brake 7. To do. Since the current flowing through the electromagnetic powder clutch 2 or the electromagnetic powder brake 7 flows through the resistor 37 connected in series to this circuit, the resistor 37
The voltage generated at both ends of, i.e., the voltage having a value proportional to the current flowing through the electromagnetic powder clutch 2 or the electromagnetic powder brake 7 is input to the PWM circuit 15. In the PWM circuit 15, the current command value input from the control circuit 16 corresponding to the torque value set by the setting panel 17 as the setting means and the electromagnetic powder clutch 2 or the electromagnetic powder brake 7 detected by the resistor 37 flows. Compare with the voltage showing the current value, according to the deviation value, according to the preset conditions,
The pulse width of the pulse train output from the PWM circuit is automatically changed so that this deviation becomes zero. Therefore, the electromagnetic powder clutch 2 or the electromagnetic powder brake 7 accurately transmits the torque set by the setting means 17 or absorbs the brake torque set by the setting means 17 by the circuit shown in FIG. Control circuit 16
When the preset over-excitation time has elapsed, the switch circuit 11 is controlled to switch the rectifier circuit to a bridge type rectifier circuit, and the signal to the PWM circuit is converted according to the preset command content to change the electromagnetic powder clutch 2 or The control voltage or current output to the electromagnetic powder brake 7 is used to generate a desired torque. Due to the function of the circuit described above, when each pulse width of the pulse train is wide, that is, when the modulation degree of PWM is large, the current flowing through the electromagnetic powder clutch 2 or the electromagnetic powder brake 7 becomes large. On the contrary, when each pulse width of the pulse train is narrow, that is, P
When the modulation degree of the WM is small, the current flowing through the electromagnetic powder clutch 2 or the electromagnetic powder brake 7 is small. That is, the current flowing through the electromagnetic powder clutch 2 or the electromagnetic powder brake 7 is large when the duty ratio of the pulse train is large, and the current flowing through the electromagnetic powder clutch 2 or the electromagnetic powder brake 7 is small when the duty ratio of the pulse train is small. Becomes small. As described above, when the current flowing through the electromagnetic powder clutch 2 is large, the torque transmitted is large, and the brake torque absorbed by the electromagnetic powder brake 7 is large. On the contrary, when the current flowing through the electromagnetic powder clutch 2 is small, the torque transmitted is small and the brake torque absorbed by the electromagnetic powder brake 7 is small. Therefore, a current corresponding to the desired torque value set by the setting panel 17 flows to the electromagnetic powder clutch 2 or the electromagnetic powder brake 7, and the desired torque is transmitted in the electromagnetic powder clutch 2 and desired in the electromagnetic powder brake 7. The braking torque is absorbed.

Next, the operation and action of the control device will be described in more detail with reference to FIG. FIG. 3 shows time-dependent changes in the electromagnetic powder clutch 2 and electromagnetic powder brake 7 associated with operation commands and the corresponding operating conditions. The upper side of the vertical axis shows the operating state of the clutch, and the lower side shows the operating state of the brake. It corresponds to the horizontal axis showing the time transition. However, for convenience of explanation corresponding to the drawing size, the time ratio of the time transition axis and the level ratio shown on the vertical axis are not correct. When the control signal 18 inputs the start command for the electromagnetic powder clutch 2 to the control circuit 16 at timing t1, the control circuit 16 sends a switching signal to the switch circuit 11 to increase the voltage output from the first rectifier circuit 10 and A preset value for commanding a preset overexciting current Ic1 is input to the PWM circuit 15 corresponding to this output voltage. In addition, the control circuit 1
6 outputs an operation signal to the switch transistor 35.
Therefore, a commanded overexciting current flows through the exciting coil of the electromagnetic powder clutch 2, so that the electromagnetic powder clutch 2 quickly rises and starts operating, and a predetermined torque is transmitted from the driving power source 1 to the load mechanism 3. Get started. The control circuit 16 outputs a set value designating the overexciting current Ic1,
At a timing t2 after a lapse of a predetermined time set in advance, a switching signal is sent to the switch circuit 11 so as to lower the output voltage from the first rectifier circuit 10, and the switch circuit 11 responds to the voltage output from the first rectifier circuit 10. Then the PWM circuit 15
The preset value for commanding the exciting current Ic2 set in advance is input in place of the preset value for commanding the overexciting current Ic1. Therefore, a commanded operating current flows through the exciting coil of the electromagnetic powder clutch 2, so that the electromagnetic powder clutch 2 continues to transmit a predetermined torque from the driving power source 1 to the load mechanism 3. When the control signal 18 inputs an activation command for the electromagnetic powder brake 7 to the control circuit 16 at timing t3 in place of the operation of the electromagnetic powder clutch 2, the control circuit 16 causes P
The input signal to the WM circuit 15 is stopped. Therefore, no current flows in the exciting coil of the electromagnetic powder clutch 2, so that the energy stored in the electromagnetic powder clutch 2 circulates through the secondary winding 32b of the switch transformer 32, and the energy is promptly increased by the circuit resistance. Decay. The control circuit 16 stops the input signal to the PWM circuit 15 and then elapses a predetermined time after a predetermined time elapses, thus timing t4.
Then, the operation signal output to the switch transistor 35 is stopped and the operation signal is output to the switch transistor 36 instead. Further, the control circuit 16 sends a switching signal to the switch circuit 11 so that the first rectifier circuit 1
The voltage output from 0 is increased and a set value for instructing the overexciting current Ib1 is output corresponding to this output voltage.
Therefore, the commanded overexcitation current flows through the exciting coil of the electromagnetic powder brake 7, so that the electromagnetic powder brake 7 quickly rises and starts to operate, and starts absorbing the predetermined brake torque from the load mechanism 3. Further, at a timing t5 after a lapse of a predetermined time set in advance, the control circuit 16 causes the switch circuit 11 to switch to the first rectifier circuit 10
A switching signal is sent so as to lower the output voltage from, and a preset value for instructing the exciting current Ib2 preset to the PWM circuit 15 is input instead of the set value for instructing the overexciting current Ib1. Therefore, the commanded operating current flows through the exciting coil of the electromagnetic powder brake 7, and the electromagnetic powder brake 7 continues to absorb the predetermined brake torque from the load mechanism 3. Hereinafter, according to the command of the control signal 18,
It works repeatedly. In the above description, the switching signal to the switch 11 and the operation signal to the PWM circuit 15 and the switch transistor 35 are simultaneously output at the timing t1, and the operation signal to the switch transistor 35 is stopped and the switch transistor 36 is output at the timing t4. And a switching signal to the switch 11 and the PWM circuit 15
It is explained that the operation signals are simultaneously output to the electromagnetic powder clutches, but the operation signals should be output and stopped appropriately in accordance with the electrical characteristics and circuit conditions of the electromagnetic powder clutch and electromagnetic powder brake. Alternatively, it is also possible to operate the electromagnetic powder clutch 2 or the electromagnetic powder brake 7 at any other arbitrary timing and level by setting them in advance from the operation panel or by inputting an appropriate control signal. Although it has been described that the output DC voltage from the first rectifying circuit 10 is increased by the switching operation by the switch 11 for overexcitation, this switching operation is performed according to the required level of overexcitation and the characteristics of this switching circuit. Except for this, the DC voltage output from the rectifier circuit 10 may be kept constant without changing. Further, at the timing t2, the switch 11 is switched and the pulse train output from the PWM circuit is changed at the same time. However, the switch timing of the switch 11 and the switching timing of both switches are changed in accordance with the characteristics of each circuit. It is also possible to make them different by presetting or by inputting a control signal. Although the first rectifier circuit 10 has been described above as being provided with a bridge type and a voltage doubler rectifier circuit, any rectifier circuit such as a full bridge type and a half bridge type may be provided. Further, two or more types of rectifying circuits may be provided so that two or more types of voltages can be output, and the switch 11 may be configured in accordance with the number of types of rectifying circuits and necessary conditions. Further, the first rectifier circuit 10 configured to output different DC voltages, except for the switch circuit 11, is connected to an AC power supply line of 200 V and a AC power supply line of 100 V, for example. It can be adapted to different AC power supplies.

The above description is for the basic structure and the basic implementation method of each of the embodiments of the present invention, and other application modifications are possible. For example, in the above description, an electromagnetic powder clutch or electromagnetic powder brake was used as the electromagnetic clutch or brake, but any torque that can be transmitted or absorbed by the supplied current or voltage can be controlled. For example, it can be applied to any clutch or brake. Also, in the above description, the case where the switching circuit is the half bridge type has been described, but when the current to be supplied to the electromagnetic clutch or the electromagnetic brake is about 10 amperes, the above half bridge circuit is suitable, but the electromagnetic clutch Alternatively, when the current to be supplied to the electromagnetic brake is larger, a full bridge type in which the capacitors 21 and 22 are replaced by switching transistors may be used. Further, the active element such as each switching element has been described as a transistor, but other switching elements such as FET may be used, and the driving circuit of the switching element may have a circuit configuration other than the above. .. Further, although the explanation has been given that the pulse train for switching is created by the PWM circuit, other means for changing the duty ratio of the pulse train in accordance with a predetermined set value may be used.
Alternatively, the pulse period may be changed.

Further, although no circuit component for filtering is shown after the first rectifying circuit or the second rectifying circuit, the filtering function is appropriately configured according to the electromagnetic clutch or electromagnetic brake to be used and other conditions of this circuit. Just do it. Also, although a resistor inserted in series with the circuit is used to detect the current value flowing through the electromagnetic powder clutch / brake, CT (current transformer for instrument) may be used. Further, even if the voltage control is performed by detecting the voltage across the electromagnetic powder clutch / brake according to the type of the electric signal corresponding to the set torque value in the setting means 17, the switching transformer 32 can detect the voltage. Other means such as providing a third winding may be used. Alternatively, the torque value may be directly detected. In addition, although it has been described that various settings are made on the operation panel, a semi-fixed switch may be provided in a predetermined circuit section in the torque control device, and the setting signal is set by a setting signal instructed by the host control device. Other suitable setting means can be used. Further, as described above, the first rectifier circuit 10 can be set to an electromagnetic clutch or an electromagnetic brake to expand the torque range that can be controlled by making the rectification system switchable. However, depending on the conditions, the means for obtaining two or more kinds of DC outputs in the first rectifier circuit may be omitted.
Further, although the control circuit 16 has been described as being sequentially controlled by the control signal 18 output from a higher-order control device (not shown), the control device itself has the entire control function and the sensor signal of the mechanical device is provided. And so on. In addition, the control circuit 16 and the PWM circuit 1
5 may be commonly used or the allocation of functions may be changed, or the like may be arbitrarily set according to the conditions of the device.

[0017]

As described above, the torque control device for the electromagnetic clutch and the electromagnetic brake according to the present invention is configured as described above, so that the following excellent effects can be obtained. 1) The torque transmitted by the electromagnetic clutch or the brake torque absorbed by the electromagnetic brake can be freely and accurately controlled. 2) The torque to be transmitted by the electromagnetic clutch or the brake torque to be absorbed by the electromagnetic brake can be freely set. 3) When the overexciting current is supplied for a predetermined time, the startup of the electromagnetic clutch and the electromagnetic brake can be accelerated. 4) When the excitation current supply is stopped for a predetermined time, it is possible to eliminate the possibility of mutual interference when switching the operation of the electromagnetic clutch and the electromagnetic brake. 5) When the supply of the exciting current is stopped for a predetermined time when the operation of the electromagnetic clutch or the electromagnetic brake is stopped, damage to the semiconductor or the like due to overvoltage when making the circuit non-conductive and malfunction due to noise can be prevented. 6) Since the circuit frequency can be high, the switching transformer becomes lightweight and compact. 7) Since the loss is reduced, the heat generation can be suppressed low even by a small heat dissipation mechanism. 8) A large-capacity electromagnetic clutch / brake control device can be made compact and lightweight. 9) When the half bridge type is used for the switching circuit, the optimum torque control device can be obtained for a normal large electromagnetic clutch / brake that allows a current of about 10 amperes to flow. 10) When a PWM circuit is used in the pulse train generation circuit, the pulse train that operates the switching circuit can be easily obtained with high accuracy corresponding to the torque value desired for the electromagnetic clutch / brake. 11) Torque control of electromagnetic clutches and brakes according to the present invention for different AC power supplies when the first rectifier circuit for obtaining DC power from the AC power supply is configured so as to obtain at least two types of DC voltage. Applicable device. 12) When the first rectifier circuit that obtains direct current from the alternating current power supply is configured to obtain at least two types of direct current voltage, a strong overexcitation function can be obtained.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing a circuit configuration in a torque control device for an electromagnetic clutch and an electromagnetic brake according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing the structure of an electromagnetic powder clutch / brake according to an embodiment of the present invention.

FIG. 3 is a timing chart for explaining overall operation of the electromagnetic clutch and the electromagnetic brake in the embodiment according to the present invention.

FIG. 4 is a schematic block diagram illustrating the usage of an electromagnetic clutch.

FIG. 5 is a schematic block diagram illustrating the usage of an electromagnetic brake.

FIG. 6 is a schematic block configuration diagram illustrating a usage when an electromagnetic clutch and an electromagnetic brake are mixedly used.

FIG. 7 is a block circuit diagram illustrating a configuration of a conventional electromagnetic clutch or electromagnetic brake control device.

[Explanation of symbols]

 1: Driving power source (electric motor) 2: Electromagnetic clutch 3: Load mechanism 4: AC power supply 6: Mechanism device having a driving function 7: Electromagnetic brake 9: Fixed part 10: First rectifying circuit 12: Switching circuit 13: Second rectifier circuit 15: Pulse train creation circuit (PWM circuit) 16: Control circuit 17: Setting means (operation panel) 21, 22: (for bridge) capacitor 23, 24: Switching element (transistor) 26, 29: Transistor 32 : Switching transformer 37: Current detection means (resistor)

Claims (6)

[Claims] 1. A torque control device for an electromagnetic clutch and / or an electromagnetic brake, wherein a predetermined drive torque is transmitted by an electromagnetic clutch, and a predetermined brake torque is absorbed by an electromagnetic brake. 1 rectifier circuit, a bridge type switching circuit that converts the direct current into a predetermined pulse train, a second rectifier circuit that rectifies the pulse train and supplies the pulse train to the electromagnetic clutch or electromagnetic brake, and the electromagnetic clutch or electromagnetic brake. A command to create the voltage or current is supplied according to the preset conditions corresponding to the operating condition of the device including the electromagnetic clutch and / or the electromagnetic brake, and is absorbed by the driving torque transmitted by the electromagnetic clutch and / or the electromagnetic brake. The electric power that regulates the braking torque A control circuit for instructing a voltage value or a current value to be supplied to a magnetic clutch or an electromagnetic brake in accordance with a preset condition, setting means for setting the control condition of the control circuit to a desired condition, and the setting means. And a pulse train creating circuit for creating a pulse train having a cycle and a duty ratio according to a predetermined condition corresponding to a voltage value or a current value supplied to the electromagnetic clutch or electromagnetic brake, and supplying the electromagnetic clutch and / or electromagnetic brake. The switching circuit is provided with a pulse train created by the pulse train creating circuit, comprising means for turning on and off a voltage or current to be applied by a command from the control circuit, and means for detecting an applied voltage or flowing current to the electromagnetic clutch or electromagnetic brake. Is activated and is detected by the detection means Obtained by the pulse train creating circuit so as to compare the voltage value or current value with the voltage value or current value created by the control circuit and zero the deviation value based on the deviation value obtained as a result of the comparison. While correcting the duty ratio of the pulse train,
By executing turning on and off of a voltage or a current supplied to the electromagnetic clutch and / or the electromagnetic brake according to a command from the control device, a driving torque transmitted by the electromagnetic clutch or a brake torque absorbed by the electromagnetic brake is set by the setting means. A torque control device for an electromagnetic clutch and an electromagnetic brake, wherein each timing and torque value of a set condition are maintained. 2. The control circuit of the torque control device for an electromagnetic clutch and an electromagnetic brake according to claim 1, wherein an overexcitation current is supplied for a predetermined time at the start of operation of the electromagnetic clutch and / or the electromagnetic brake, Alternatively, the torque control device for an electromagnetic clutch and an electromagnetic brake according to claim 1, wherein the electromagnetic brake and the electromagnetic brake are formed so as to shorten an activation time of the electromagnetic brake. 3. The control circuit of the torque control device for an electromagnetic clutch and an electromagnetic brake according to claim 1, wherein an exciting current stop time of a predetermined time length is provided at the end of operation of the electromagnetic clutch and / or the electromagnetic brake. 2. The torque control device for an electromagnetic clutch and an electromagnetic brake according to claim 1, wherein the electromagnetic clutch and the electromagnetic brake are formed so as to prevent mutual interference during mutual switching of the electromagnetic brake. 4. The torque control device for an electromagnetic clutch and an electromagnetic brake according to claim 1, wherein the bridge type switching circuit according to claim 1 is a half bridge type. 5. The pulse train generation circuit according to claim 1 is a PW.
The electromagnetic clutch and electromagnetic brake torque control device according to claim 1, wherein the torque control device is an M circuit. 6. The electromagnetic system according to claim 1, wherein the rectifier circuit for converting the AC power supply into DC according to claim 1 can switch at least two kinds of rectifier circuits that output different DC voltages. Torque control device for clutch and electromagnetic brake.