JPS6174306A - Driving circuit for solenoid - Google Patents

Abstract

PURPOSE:To shorten the rise time of a current flowing to a first coil, by impressing on the first coil a surge voltage generated when the current of a second coil is interrupted. CONSTITUTION:When a control signal is given to an input terminal 24, a switch 17 operates to open or close according to this signal. The control signal given to the terminal 24 is given also to a switch 19 through an inverter circuit 25, and thereby the switch 19 operates reversely to the switch 17. By the opening and closing operations of the switches 17 and 19, solenoid coils 12 and 12a are excited alternately. When the switch 17 turns open, a surge voltage is generated in the coil 12. This surge voltage is applied to the coil 12a through a varistor 23.

Description

[Detailed description of the invention] The present invention aims to solve the following problems.

(Industrial Application Field) The present invention relates to a solenoid drive circuit for driving a solenoid coil for operating a mover in a solenoid valve or other electromagnetic device.

(Prior art) In the conventional solenoid drive circuit,
A switch is interposed in the energizing circuit from the power source to the solenoid coil, and the switch is turned on and off to open and close the energization to the above coil, thereby controlling the operation of the mover. When the solenoid coil is too hot, it is difficult for current to flow through the solenoid coil, and as a result, it takes a long time for a predetermined current to flow through the solenoid coil, causing a problem in that the operation of the movable element is delayed.

(Problems to be Solved by the Invention) This invention eliminates the above-mentioned conventional problems, and of course can control the energization and de-energization of the coil by opening and closing a switch, and can move the mover forward and backward in response. An object of the present invention is to provide a solenoid drive circuit that can instantaneously start up the current flowing through the coil when the switch is closed to move the movable element forward, thereby quickly moving the movable element forward. It is something to do.

The configuration of the present invention is as follows.

(Means for Solving the Problems) The present invention takes the measures as described in the claims above, and its effects are as follows.

(Operation) When the first switch is closed, current attempts to flow through the switch to the first coil. At this time, since the second switch opens at the same time, a reverse power is generated in the second coil, and the reverse voltage is applied to the first coil through the surge current passing element. As a result, the current flowing through the first coil rises instantaneously.

(Embodiments) The drawings showing the embodiments of the present application will be explained below. In FIG. 1, ■ indicates a well-known valve device, in which 2 is the valve body, 3 is the spool, 4 is the pump port,
5 is a tank boat, 6 and 7 are ports connected to a controlled device, 10 is a well-known solenoid, 11 is a yoke, 12 is a solenoid coil, 13 is a movable core, and 14 is an interlocking rod, which is a movable core. 13 and the spool 3. Note that the solenoid 10a shown on the right side of the figure has the same structure as the above solenoid, so
Functionally equivalent parts are marked with the same reference numeral and alpha vent a.
will be added to omit duplicate explanations. In this specification, the solenoid coil 12 is also referred to as a first coil, and the solenoid coil 12a is also referred to as a second coil.

Next, 16 indicates a power supply, for example, a 24V DC power supply is used. Reference numeral 17 denotes a first switch, which is composed of a transistor. Reference numeral 18 indicates a diode for preventing current from flowing in the opposite direction to the transistor. Reference numeral 19 indicates a second switch, which is composed of a transistor.

20 is a diode similar to the diode 18 described above.

21 and 22 are surge absorbers, respectively, and the above switch 1
This is to protect the transistor used as 7°19, and a varistor is used. 23 is a surge current passing element, for example a varistor is used. This surge! A capacitor can also be used as the flow passage element 23. The varistor voltage and voltage i1[16
The relationship with the voltage of the surge current passing element 23 is such that the varistor voltage of the surge current passing element 23 is selected to be higher than the ta voltage (and lower than the surge voltage generated in the coil 12.123, and the varistor voltage of the surge absorber 21. higher than that of element 23 (and lower than the withstand voltage of transistor 17. It is connected to the base of the transistor used as the switch 19 through the circuit 25 and the coupling circuit 26.The coupling circuit 26 is for separating the inverting circuit 25 and the switch 17 in terms of direct current, and for example, a photocoupler is used. Next, the operation of the above structure will be explained with reference to Fig. 2. First, when a control signal is applied to the input terminal 24 as shown in Fig. 2(a),
The switch 17 opens and closes accordingly. On the other hand, the control signal is also applied to the switch 19 through the inverting circuit 25 and the coupling circuit 26, so that the switch 19 operates in the opposite direction to that of the switch 17.

That is, when switch 17 is open, switch 19 is closed, and when switch 17 is closed, switch 19 is closed.
is open (as mentioned above, since the switches 17 and 19 operate to open and close, the first solenoid coil 12 and the second solenoid coil 12a are connected alternately as shown in FIGS. 2(b) and 2(c)). A voltage is applied to the solenoids, and current flows alternately through the solenoids as shown in FIGS. Then, the mover 13 moves to the position shown in FIG. 1, and the spool 3 moves to the shown position via the interlocking rod 14.

As a result, oil flowing into port 4 flows out from port 7 and oil returning to port 6 returns to the tank from port 5. On the other hand, when a current flows through the coil 12a, an electromagnetic force is applied to the movable element 13a, and the movable element 13a moves to the left in FIG. This movement is controlled by the spool 3 via the interlocking rod 14a.
As a result, oil flowing into the boat 4 flows out from the port 5, and oil returning to the boat 7 returns to the tank from the port 6. Such an operation is repeated each time the current alternately flows through the coil 12.12a.

When switching from a state where current flows through the first coil 12 to a state where current flows through the second coil tZa as described above, or vice versa, the following operation is performed. When the switch 17 is opened, a large reverse voltage (also called surge voltage) is generated in the coil 12. This reverse voltage passes through the surge current passing element 23 to the second coil 12a.
join.

As a result, the surge current due to the surge voltage is transferred to the coil 1.
2 and the coil 12a.

Therefore, a current Io/2, which is approximately 1/2 of the current value 1o that had been flowing through the first coil 12, flows through the coil 12a. At the same time or immediately after that, the switch 19 is closed, so that the current flowing through the second coil 12a starts to increase from the above-mentioned 1/2 current value, that is, the value at point (a) shown in FIG. 3. Therefore, the time required for the current flowing through the coil 12a to reach a value sufficient to operate the movable element 13a as described above (see FIG. 3 TI) is longer than that of the conventional circuit section
The time T2 is much shorter than the above-mentioned time T2 in a circuit in which the current to 2a is only opened and closed by a switch, and as a result, the movable element 13a can be operated very quickly. Similarly, when the coil 12a is opened, the surge voltage generated in the coil 12a passes through the surge current passing element 23 and is applied to the first coil 12, so that the current flowing through the coil 12 rises quickly.

As a result, the mover 13 can be operated quickly.

Next, FIG. 4 shows a different embodiment of the present application, and in FIG. I'm trying to get it back in the right direction. Also, only one solenoid is used so that the spool 3e
It should be activated. Further, as the second coil, an arbitrary coil 32 (for example, a chiller coil) can be used instead of the solenoid coil described above. Furthermore, the first and second switches 17e and 19s are mechanically interlocked switches that are alternately opened and closed by pushing and pulling the operating piece 33.

Even with this configuration, as in the previous embodiment, the current flowing through the coil 12e can be opened and closed by opening and closing the switch 17e by operating the operating piece 33.
Furthermore, when the switch 17e closes and current starts flowing through the coil 12e, the reverse voltage generated in the coil 32 can be applied to the coil 12g through the surge current passing element 23e, and the current in the coil 12e is instantaneously changed as in the previous case. can be launched. Note that the above switches 17e and 19e
is constructed using contacts that operate in conjunction with the relay coil 34, and the energization of the relay coil is controlled by a switch 35.
The contacts 17g and 19e may be alternately opened and closed by opening and closing the switch 35.

It should be noted that parts that are considered to be functionally the same or equivalent to those in the previous figure are given the same reference numerals as in the previous figure with the letter e, and redundant explanations are omitted.

(Effects of the Invention) As described above, in the present invention, when it is desired to operate the mover, the first coil 12 is energized or de-energized by controlling the opening and closing of the first switch 17.
It has the advantage that the mover 13 can be moved forward and backward in response to this.

Furthermore, in the case described above, when the first switch 17 is closed to move the mover 13 forward, when the first switch 17 is closed, current flows through it to the first coil 12, and at the same time, the second switch 17 is closed. When the switch 19 is opened, the reverse voltage of the second coil 12a at that time is applied to the surge current passing element 23.
It has the feature that the current flowing through the first coil 12 can be instantaneously increased. This means that the first coil 12 can quickly apply a large electromagnetic force to the mover 13.
This has the effect of allowing the mover 13 to move forward quickly.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and Fig. 1 schematically shows the structure of a solenoid valve and the related configuration of the solenoid valve and the drive circuit. Fig. 2 is an operating waveform diagram of the circuit in Fig. FIG. 3 is a graph showing the relationship between time and coil current, and FIG. 4 is a diagram similar to FIG. 1 showing a different embodiment. 12...first coil, 12...second coil, 1
7... first switch, 19... second switch,
23... Surge current passing element. Figure 1 Figure 3 (61″%Z) A1 Shinoden 1 Otsu 84m Work rlr Work L

Claims (1)

[Claims] One end and the other end of a first coil for operating the mover are connected to one end and the other end of a series circuit of a first switch and a power source, respectively, so as to correspond to the closing and opening of the switch. In the solenoid drive circuit in which the current from the power source is energized or de-energized to the first coil, a connection point between the first coil and the power source has an operation opposite to that of the first switch. one end on the second switch side of a series circuit of the second switch and the second coil is connected, and the other end of the series circuit is connected to the connection point between the first switch and the power source, and , a solenoid characterized in that a surge current passing element is interposed between a connection point between the first coil and the first switch and a connection point between the second switch and the second coil. drive circuit.