JPH04304194A - Motor control circuit - Google Patents

Abstract

PURPOSE:To reverse rotational direction of motor and opening/closing direction of valve by switching contact switches and limit switches, connected to the positive and negative pole sides of a motor control circuit disposed between a DC power supply and a DC motor, by means of a voltage to be applied on a solenoid. CONSTITUTION:Contact switches CR1, CR2 and limit switches LS1, LS2 are connected in series with the positive pole P side and negative pole N side of a motor control circuit 1. The limit switches LS1, LS2 detect displacement of a pushing means (not shown) which is driven by a linear motion converted from the rotary motion of a motor 40. When the switch SW1 of a sequencer 2 is turned ON, a solenoid SL is excited and the contact switches CR1, CR2 are connected, respectively, with positive and negative poles P, N, contrary to the case shown on the drawing, and thereby the motor 40 rotates forward to close a valve (not shown). Upon turn OFF of the switch SW1, the SL is de-energized and the CR1, CR2 are connected as shown on the drawing and thereby the motor 40 rotates reversely to open the valve. The operation is reversed when the polarities of the power supply terminals T1, T2 are reversed. According to the invention, ON/OFF control of valve is facilitated.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a motor control circuit.
In particular, the present invention relates to a motor control circuit that controls the direction of current applied to a DC motor.

0002

2. Description of the Related Art A valve mechanism as shown in FIGS. 4 and 5 has been proposed as a valve mechanism constituting a flow path system of a bio-related device or the like. FIGS. 4 and 5 are schematic cross-sectional views of main parts for explaining the operation of a conventional valve mechanism. Further, FIG. 6 is a diagram showing the main parts of the DC motor that drives this valve mechanism and its control circuit.

In FIGS. 5 and 6, the flow path of a flexible tube 22 placed on a base 21 moves up and down via a rotatable shaft 23 as the DC motor rotates. It is opened and closed by the pressing body 24. That is, a threaded portion 25a is formed at the lower part of the shaft 23 rotated by a DC motor, and the threaded portion 2 of the pressing body 24 is attached to this threaded portion 25a.
5b are screwed together. In order to restrict the rotation of the pressing body 24, a guide groove 27 is formed in the axial direction on the inner wall of the cylindrical casing 26 that accommodates the shaft portion of the pressing body 24, and a guide groove 27 is formed in the axial direction on the inner wall of the cylindrical casing 26 that accommodates the shaft portion of the pressing body 24. A protrusion 28 that is slidable along the guide groove 27 in the axial direction is formed. The threaded portions 25a, 25b, the guide groove 27 and the convex portion 28 are
It functions as a conversion mechanism that converts the rotation of the shaft 23 into vertical movement. When the DC motor 40 shown in FIG. 6 rotates forward, the pressing body 24 descends as the shaft 23 rotates, closing the flow path of the flexible tube 22. When the DC motor 40 rotates in reverse, the pressing body 24 rises as the shaft 23 rotates, and the flow path of the flexible tube 22 opens.

[0004] The opening and closing of the flow path by the pressing body 24 is detected by a detection means. This detection means includes the pressing body 2
4, and limit switches 30a and 30 for switching the rotation and stop of the DC motor 40 in response to the vertical movement of the switch operating member 29.
0b. That is, when the pressing body 24 is lowered to close the flow path of the flexible tube body 22, as shown in FIG. is detected. On the other hand, when the pressing body 24 is raised to open the flow path of the flexible tube body 22, the switch operating member 29 comes into contact with the upper limit switch 30b, and the flow path is opened, as shown in FIG. An open position is detected.

Such a valve mechanism is mainly controlled by a sequencer 20 shown in FIG. 7, and the direction of rotation of the DC motor 40 is switched by the operation of a relay in the motor control circuit 10.

The motor control circuit 10 includes a relay consisting of a solenoid SL and contact switches CR1 and CR2. One power terminal T1 of the motor control circuit 10 is connected to the positive pole of the DC power supply 30 via the positive power line P, and the other power terminal T2 is connected to the negative pole of the DC power supply 30 via the negative power line N. . Further, a signal terminal T3 for switching the rotation direction of the DC motor 40 is connected to the signal line S. This signal line S is connected to the positive power supply line P via a switch SW1 in the sequencer 20. On the other hand, the DC motor 40
is connected between output terminals T4 and T5 of the motor control circuit 10.

In this motor control circuit, the sequencer 20
When switch SW1 inside is open, no current flows through solenoid SL and the relay does not operate. Therefore,
Contact switches CR1 and CR2 of the relay are connected to the contact b side, as shown in FIG. In this case, the current flows from the power terminal T1 to the DC motor 40 via the contact switch CR2 and the output terminal T5, and further the current flows from the output terminal T4 to the power terminal T2 via the contact switch CR1. Therefore, the DC motor 40 reverses, thereby opening the valve.

On the other hand, the switch S in the sequencer 20
When W1 is closed, current flows from the positive power line P to the negative power line N via the switch SW1, the signal line S, and the solenoid SL. Thereby, the relay operates, and the contact switches CR1 and CR2 are switched to the contact a side. in this case,
The current flows from the power supply terminal T1 to the DC motor 40 via the contact switch CR1 and the output terminal T4, and further the current flows from the output terminal T5 to the power supply terminal T2 via the contact switch CR2. Therefore, the DC motor 40 rotates normally, thereby closing the valve.

[0009]

As described above, in the motor control circuit 10 shown in FIG. 7, the valve closes when the relay operates, and opens when the relay does not operate.

In this motor control circuit 10, temporarily,
As shown in FIG. 8, when the connections of the positive power line N and the negative power line P are reversed, current flows in the DC motor 40 in the opposite direction. However, even if the switch SW1 in the sequencer 20 is closed, no current flows through the solenoid SL of the relay, and the relay does not operate. In this case, if the switch SW1 is somehow connected to the negative power supply line N, a current in the opposite direction will flow through the solenoid SL.

In this manner, the motor control circuit 10 shown in FIG. 7 is capable of closing the valve when the relay operates and opening the valve when the relay does not operate. It is not possible to have the valve open at times and close when the relay is not working without changing the wiring of the relay. Changing the wiring of this relay generally involves changing the entire sequencer 20, which is impractical.

In the motor control circuit 10, if the relay stops operating due to an accident such as a disconnection of the signal line S, it becomes impossible to close the valve. In such cases, it is convenient to close the valve if the reverse operation is possible.

Therefore, an object of the present invention is to reverse the relationship between the operation of the relay and the direction of rotation of the DC motor by simply reversing the connection of the positive and negative power supply lines from the normal connection. An object of the present invention is to provide a motor control circuit.

[0014]

[Means for Solving the Problems] A motor control circuit according to the present invention is a motor control circuit that controls the direction of current provided to a DC motor from a DC power supply, and includes a first power supply terminal, a second power supply terminal, and a second power supply terminal. terminal, switching means, signal terminal, excitation means,
A first rectifying means and a second rectifying means are provided.

[0015] The first power supply terminal is connected to one terminal of the DC power supply, and the second power supply terminal is connected to the other terminal of the DC power supply. The switching means switches the connection between the first and second power supply terminals and the DC motor. The signal terminal is selectively set to a coupled state or an open state to a predetermined potential. The excitation means has a first terminal and a second terminal connected to the signal terminal, and drives the switching means.

The first rectifying means causes current to flow from the second terminal of the excitation means to the first power supply terminal. The second rectifying means is
A current is passed from the second terminal of the excitation means to the second power supply terminal.

Preferably, the switching means comprises contacts of an electromagnetic relay, and the excitation means comprises a solenoid of the electromagnetic relay.

Preferably, the first rectifying means includes a first diode having an anode connected to the second terminal of the excitation means and a cathode connected to the first power supply terminal, The second rectifying means includes a second diode having an anode connected to the second terminal of the excitation means and a cathode connected to the second power supply terminal.

Preferably, the motor control circuit further includes discharge means connected between the first rectifier means and the second rectifier means.

The motor control circuit is a valve motor having a member connected to the DC motor via a conversion mechanism that converts rotational motion into reciprocating motion, and a flexible pipe body opened and closed by this member. Suitably applied to a control circuit, this motor control circuit includes a detection means for detecting the open/closed position of the flexible tube, a notification means for notifying information detected by the detection means, and the notification means. and a resistance element connected to the second terminal of the excitation means.

[0021]

[Operation] When the signal terminal is set to the open state with the first power terminal and the second power terminal connected to the positive terminal and the negative terminal of the DC power source, respectively, the excitation means does not operate. Therefore, the switching means is not driven and the DC motor rotates normally. When the signal terminal is coupled to a predetermined potential in this state, a current flows from the signal terminal to the second power supply terminal via the excitation means and the second rectification means, and the excitation means is operated. Therefore, the switching means is driven and the DC motor is rotated in reverse.

Conversely, when the signal terminal is set to an open state with the first power terminal and the second power terminal connected to the negative terminal and the positive terminal of the DC power source, respectively, the excitation means is activated. Do not work. Therefore, the switching means is not driven. However, since the current flowing through the DC motor is opposite to that in the above case, the DC motor reverses. In this state, when the signal terminal is coupled to a predetermined potential, a current flows from the signal terminal to the first power supply terminal via the excitation means and the first rectification means, and the excitation means is operated. Therefore, the switching means is driven and the DC motor rotates normally.

[0023]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of a motor control circuit according to an embodiment of the present invention.

The motor control circuit 1 has power terminals T1 and T2.
, and has a signal terminal T3 and output terminals T4 and T5. Normally, one of the power terminals T1 is connected to a positive power line P, and the other power terminal T2 is connected to a negative power line N. The positive power line P is connected to the positive electrode of the DC power source 3, and the negative power line N is connected to the negative electrode of the DC power source 3. Further, the signal terminal T3 is connected to the signal line S. This signal line S is connected to the positive power supply line P via a switch SW1 in the sequencer 2. Regarding the sequencer 2, only the switch SW1 is shown, and other circuit elements are omitted. On the other hand, a DC motor 40 is connected between the output terminals T4 and T5.

A first terminal N1 of a solenoid SL of an electromagnetic relay is connected to the signal terminal T3. The second terminal N2 of the solenoid SL serving as an excitation means is connected to the one power supply terminal T1 via a diode D1 serving as a first rectifying unit, and is connected to the one power supply terminal T1 via a diode D2 serving as a second rectifying unit. It is connected to the other power supply terminal T2. The diode D1 is connected to the solenoid SL.
and a cathode connected to the first power supply terminal T1. Further, the diode D2 has an anode connected to the second terminal N2 of the solenoid SL and a cathode connected to the second power terminal T2. A diode D3 for noise removal is connected between the first terminal N1 and the second terminal N2 of the solenoid SL.

Furthermore, one contact a of a contact switch CR1 of the relay is connected to the one power supply terminal T1,
The other power supply terminal T2 is connected to the contact switch CR1.
The other contact b is connected. In addition, power terminal T2
One contact a of the contact switch CR2 of the relay is connected to the power supply terminal T1, and the other contact b of the contact switch CR2 is connected to the power supply terminal T1. The contact switch CR
1, CR2 are the power terminals T1, T2 and the DC motor 4.
It functions as a switching means for switching the connection with 0.

The terminal c of the contact switch CR1 is connected to the terminal COM of one limit switch LS1, and the terminal c of the contact switch CR2 is connected to the terminal COM of the other limit switch LS2. The contact switches CR1 and CR2 are normally set on the contact b side, and are switched to the contact a side when the solenoid SL is excited. The limit switches LS1 and LS2 are
As shown in FIGS. 5 and 5, the displacement of the switch operating member 29 of the pressing body 24 connected to the DC motor 40 is detected through a conversion mechanism that converts rotational motion into reciprocating motion. It functions as a switch means constituting the detection means.

A contact NC of the one limit switch LS1 is connected to the one output terminal T4, and a contact NC of the other limit switch LS2 is connected to the other output terminal T5. Said limit switch LS1
A light emitting diode D8 as a notification means is connected between the contact NO and the connection point N3, and the limit switch LS
A light emitting diode D9 serving as a notification means is connected between the light emitting diode D9 and the connection point N3. Limit switch LS1
, LS2 are usually set on the contact NC side.

The limit switch LS1 switches to the contact NO side when the pressing body 24 shown in FIGS. 5 and 6 descends and the valve is completely closed. On the other hand, the limit switch LS2 is switched to the contact NO side when the pressing body 24 is raised and the valve is completely opened.

The connection point N3 is connected via a resistor R to a connection point N4. A diode D4 is connected between the connection point N4 and the terminal c of the contact switch CR1, and a diode D5 is connected between the connection point N4 and the terminal c of the contact switch CR2. Also, limit switch L
A diode D6 is connected between the terminal NC of S1 and the terminal c of the contact switch CR1, and a diode D7 is connected between the terminal NC of the limit switch LS2 and the terminal C of the contact switch CR2.

The normal operation of the motor control circuit 1 will be explained below.

When the switch SW1 in the sequencer 2 is turned on, current flows from the positive power line P to the negative power line N via the switch SW1, solenoid SL and diode D2, as shown in FIG. As a result, solenoid S
L is excited, and contact switches CR1 and CR2 are switched to the contact a side. Therefore, current flows from the power supply terminal T1 to the DC motor 40 via the contact switch CR1, limit switch LS1 and output terminal T4, and the current flows to the power supply terminal via the output terminal T5, limit switch LS2 and contact switch CR2. Flows to T2. Then, the DC motor 40 rotates normally and the valve closes.

When the valve is completely closed, the limit switch LS1 is switched to the contact NO side. As a result, a current flows from the power supply terminal T1 to the light emitting diode D8 via the contact switch CR1, and the current further flows to the power supply terminal T2 via the resistor R, the diode D5, and the contact switch CR2. As a result, the light emitting diode D8 emits light to notify that the bulb is closed. At this time, since no current flows through the DC motor 40, the rotation of the DC motor 40 stops.

On the other hand, the switch SW in the sequencer 2
When solenoid SL is turned off, no current flows through solenoid SL. Therefore, the solenoid SL is not excited, and the contact switches CR1 and CR2 return to the contact b side. Thereby,
Current flows from power supply terminal T1 to DC motor 40 via contact switch CR2, limit switch LS2 and output terminal T5, and the current further flows to power supply terminal T2 via output terminal T4, diode D6 and contact switch CR1. . Then, the DC motor 40 rotates in reverse, and the valve opens. Thereby, the limit switch LS1 is switched to the contact NC side.

When the valve is completely opened, the limit switch LS2 is switched to the NO contact side. As a result, a current flows from the power supply terminal T1 to the light emitting diode D9 via the contact switch CR2, and the current further flows to the power supply terminal T1 via the resistor R, the diode D4, and the contact switch CR1. As a result, the light emitting diode D9 emits light to notify that the valve has opened. At this time, since no current flows through the DC motor 40, the DC motor 40
rotation stops.

When the switch SW1 in the sequencer 2 is turned on again, current flows through the solenoid SL, and the contact switches CR1 and CR2 are switched to the contact a side. The current flows from the power supply terminal T1 to the contact switch CR1 and the limit switch L.
The current flows to the DC motor 40 via S1 and the output terminal T4, and the current further flows to the power supply terminal T2 via the output terminal T5, the diode D7, and the contact switch CR2. Then, the DC motor 40 rotates forward and the valve opens. Thereby, the limit switch LS2 is switched to the contact NC side.

In this way, the switch SW in the sequencer
1 is on, the DC motor 40 rotates forward, and the switch S
When W1 is off, the DC motor 40 rotates in reverse.

Further, the operation when the power terminal T1 is connected to the negative power line N and the current terminal T2 is connected to the positive power line P will be described.

In this case, as shown in FIG. 3, when switch SW1 in sequencer 2 is on, current flows from positive power line P to negative power line N via switch SW1, solenoid SL and diode D1. Thereby,
Solenoid SL is energized and contact switches CR1, CR
2 switches to the contact a side. The current flows from the power supply terminal T2 to the DC motor 40 via the contact switch CR2, limit switch LS2 and output terminal T5, and the current flows to the power supply terminal T1 via the output terminal T4, limit switch LS1 and contact switch CR1. flows. Then, the DC motor 40 rotates in reverse, and the valve opens.

On the other hand, when the switch SW1 in the sequencer 2 is off, no current flows through the solenoid SL. Therefore, the solenoid SL is not excited, and the contact switches CR1 and CR2 return to the contact b side. Therefore, the current is
The current flows from power supply terminal T2 to DC motor 40 via contact switch CR1, limit switch LS1 and output terminal T4, and further flows to power supply terminal T1 via output terminal T5, limit switch LS2 and contact switch CR2. As a result, the DC motor 40 rotates normally and the valve closes.

In this way, the switch S in the sequencer 2
When W1 is on, the DC motor 40 rotates in reverse, and when switch SW1 is off, the DC motor 40 rotates in the normal direction.

According to the motor control circuit 1 of this embodiment,
Even if the connections of the power terminals T1 and T2 to the positive power line P and the negative power line N are reversed, the direction of the current flowing through the solenoid SL of the relay does not change, and the relationship between the operation of the relay and the rotation direction of the DC motor 40 is can be reversed.

Therefore, even if an accident such as disconnection of the signal line S occurs, the DC motor 40 can be reversed by simply reversing the connections of the positive power line P and the negative power line N.

Note that in the control circuit of the above embodiment, diodes D1 and D2 for relay operation and diodes D4 and D
5 is used for the same purpose of rectifying the current, so there is no cost advantage. Also, sequencer 2
When switch SW1 is off, diodes D1 and D2
A high voltage is charged during this time.

FIG. 4 is a circuit diagram showing the configuration of a motor control circuit according to another embodiment of the present invention.

The difference from the control circuit shown in FIG. 1 is as shown in FIG.
The diodes D4 and D5 shown in are omitted, and the connection point N3 between the light emitting diodes D8 and D9 and the second terminal N2
The point where the solenoid S is connected to the
The point is that the second terminal N2 of L and the power supply terminal T1 of the positive power supply line P are connected via the discharge resistor R1. Further, a capacitive element C is connected between the output terminals T4 and T5.

In this case, the diodes D4, D5
Even if omitted, the limit switch LS1
, LS2 detect the open/close position of the flexible tube, and based on this detection information, the light emitting diodes D8, D9 can notify the opening/closing of the flexible tube and control the rotational direction of the DC motor 40. Further, the discharge resistor R1 prevents charging between the diodes D1 and D2 as the first and second rectifying means, and the capacitor does not break down.

Note that the pressing body 2 is connected to the DC motor 40 via a conversion mechanism that converts rotational motion into reciprocating motion.
The detection means for detecting the displacement of No. 4 does not need to be composed of the switch operating member and the limit switch, and for example,
It may be composed of a switch operating member and an optical sensor that detects the position of the switch operating member, or it may be composed of a pressure sensor interposed between the flexible tube and the pressing body.

[0050]

According to the present invention, the excitation means can be operated even if the connections to the positive and negative power supply lines are reversed, and the operation of the excitation means and the switching means and the rotation direction of the DC motor can be changed. The relationship can be reversed. Therefore, when the signal terminal is opened, the DC motor can be rotated forward or reverse.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the configuration of a motor control circuit according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the normal operation of the motor control circuit of the embodiment shown in FIG. 1;

FIG. 3 is a diagram for explaining the operation of the motor control circuit when the connections of the positive power line and the negative power line are reversed.

FIG. 4 is a circuit diagram showing the configuration of a motor control circuit according to another embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of main parts for explaining the operation of the valve mechanism.

FIG. 6 is a schematic cross-sectional view of main parts for explaining the operation of the valve mechanism.

FIG. 7 is a circuit diagram showing the configuration of main parts of a conventional motor control circuit.

FIG. 8 is a diagram for explaining the operation of a conventional motor control circuit.

[Explanation of symbols]

1...Motor control circuit 2...Sequencer 3...DC power supply T1, T2...Power terminal T3...Signal terminal SL...Solenoid N1...first terminal N2...Second terminal CR1, CR2...Contact switch D1, D2...Diode D8, D9...Light emitting diode R...Resistance R1...Discharge resistance 40...DC motor

Claims (5)

[Claims] [Claim 1] A motor control circuit for switching the direction of current supplied from a DC power source to a DC motor, comprising:
A first power terminal connected to one terminal of the DC power source, a second power terminal connected to the other terminal of the DC power source, and a connection between the first and second power terminals and the DC motor. a signal terminal selectively set to a coupled state or an open state to a predetermined potential; a first terminal and a second terminal connected to the signal terminal; excitation means for driving the switching means; first rectification means for causing current to flow from a second terminal of the excitation means to the first power supply terminal; and from a second terminal of the excitation means to the second power supply terminal. A motor control circuit comprising a second rectifying means for passing current to the terminals. 2. The motor control circuit according to claim 1, wherein the switching means comprises a contact of an electromagnetic relay, and the excitation means comprises a solenoid of the electromagnetic relay. 3. The first rectifying means comprises a first diode having an anode connected to the second terminal of the excitation means and a cathode connected to the first power supply terminal;
2. The motor control circuit according to claim 1, wherein the rectifying means comprises a second diode having an anode connected to the second terminal of the excitation means and a cathode connected to the first power supply terminal. 4. The motor control circuit according to claim 1, further comprising discharging means connected between the first rectifying means and the second rectifying means. 5. A valve motor control circuit comprising: a member connected to the DC motor via a conversion mechanism that converts rotational motion into reciprocating motion; and a flexible tube body opened and closed by the member. a detecting means for detecting the open/closed position of the flexible tube; a notifying means for notifying information detected by the detecting means; and a resistor connecting the notifying means and the second terminal of the excitation means. 2. The motor control circuit according to claim 1, further comprising: an element.