JPS63140188A - Driving and controlling circuit for proportional valve - Google Patents

Abstract

PURPOSE:To make the capacity of a transformer for a proportional valve circuit small by applying individual power supplied to the proportional valve control circuit and a valve driving circuit through a process of transmitting signals of a proportional valve control circuit and the proportional valve driving circuit with a photocoupler or the like. CONSTITUTION:Together with providing a proportional valve driving circuit 2 having an electric current control circuit 7 connected to a proportional valve 6 for deciding a driving current according to an input signal V1 and an input signal forming circuit 8 for forming input signal V1 and a proportional valve control circuit 4 having a pulse signal generating circuit 16 having the pulse width according to opening/closing quantity of the proportional valve an electrically insulated signal transmitting means 20 like a photocoupler 20 is interposed between the proportional valve driving circuit 2 and the proportional valve control circuit 4. Thereby, it can be achieved to apply individual power supplies to the proportional valve driving circuit 2 and the proportional valve control circuit 4 for making capacity of a transformer 3 small through feeding only electric power to the control circuit 4 from the transformer 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a proportional valve drive control circuit for driving a proportional valve that opens in proportion to the magnitude of current.

(Prior Art) Fig. 4 shows a conventional proportional valve drive control circuit. This proportional valve drive control circuit includes a transformer (103) and a rectifier circuit (
105), and a control circuit (104) for controlling a proportional valve (10B) and the opening degree of this proportional valve (108) by this power supply circuit (+00).
It is designed to be driven directly.

That is, the control circuit (104) is equipped with a microcomputer, etc., and determines the opening degree of the proportional valve (10G) from various human input data, and applies a voltage corresponding to this determined value to the operational amplifier circuit (112).
), transistor (113) and resistor (R's)
This current control circuit (107) sends a current according to the input voltage value from the power supply circuit (100) to the proportional valve (10B) and the collector emitter of the transistor (+13). The proportional valve (10B) is driven and controlled by flowing through the gap and the resistance (R's).

(Problems to be Solved by the Invention) As described above, since the conventional proportional valve drive control circuit drives the control circuit (104) and the proportional valve (10B) on the secondary side, the power supply voltage is Due to limitations imposed by each element such as a microcomputer included in the control circuit (104), the voltage must be considerably lower than the commercial voltage (AClooV) (for example, DC 32V), and for this reason, the power supply circuit (100) must use a proportional valve. In order to drive (toe), the capacity of the transformer (103) must be increased because its current consumption is large, and it is difficult to make the entire circuit smaller and simpler.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a proportional valve drive control circuit that can reduce the size of the transformer, thereby easily achieving miniaturization and simplicity.

(Means and effects for solving the problem) A proportional valve (6) that opens in proportion to the size of the drive current, and a proportional valve (8) that is connected to the A proportional valve drive circuit (2) comprising a current control circuit (7) that determines the current (7) and an input signal formation circuit (8) that forms the input signal in this current control circuit (7); 6) Pulse width T1 according to the opening/closing amount to be operated
a proportional valve control circuit (4) comprising a pulse signal generation circuit (16) that generates a pulse signal P having a constant period;
The proportional valve drive circuit (2) and the proportional valve control circuit (4) are provided between the proportional valve drive circuit (2) and the proportional valve control circuit (4) while electrically insulating both circuits, and input the input signal Vl in the current control circuit (7) to the pulse width T!
The control signal transmitting means (20) is configured to cause the input signal forming circuit (8) to form a control signal according to the input signal forming circuit (8).

According to such a configuration, the power source for the proportional valve drive circuit (2) and the power source for the proportional valve control circuit (4) are separate power sources, and the proportional valve (6) and the proportional valve drive circuit (2) are connected to the power source side ( As a result, the current consumption on the secondary side can be reduced and the transformer capacity can be easily reduced.
As a result, the transformer can be made smaller and lighter.

(Embodiments of the Invention) A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a diagram showing a proportional valve drive circuit according to the present invention.
In the figure, (1) indicates the commercial power supply (AClooV),
A proportional valve drive circuit (2) and a proportional valve control circuit (4) are connected to this power source (1) via a transformer (3), respectively.

The proportional valve drive circuit (2) includes a proportional valve (6) connected via a full-wave rectifier circuit (5), and a drive current flowing from the rectifier circuit (5) to the proportional valve (6) based on its input signal. It consists of a current control circuit (7) for controlling and an input signal forming circuit (8) for forming this input signal.

Is this input signal forming circuit (8) connected to the output end of the aftereffect rectifier circuit (5)? 1iIi, a diode (9) that regulates the flow in one direction, resistors R1, R2, for current regulation or voltage division,
A phototransistor (10), which will be described later, is connected via R3, and a precision circuit consisting of a resistor R4 and a capacitor CI is connected between the phototransistor (lO) and the resistor R3, and the voltage between the resistors R2 and R3 is A constant voltage diode (1
1), and a smoothing capacitor C2 is provided between the resistors R+ and 12 and the ground.

The current control circuit (7) includes an operational amplifier (12) and a switching transistor (13) that causes a proportional valve drive current I to flow when the output signal of the operational amplifier (12) becomes positive.
The proportional valve drive current is adjusted so that the voltage drop due to this proportional valve electrodynamic lit I, that is, the potential at the inverting input terminal 7 (12b) of the operational amplifier (12), becomes equal to the potential at the non-inverting input terminal (12a). The non-inverting input terminal (12a) of the operational amplifier (12) is connected between the resistor R4, which is the output terminal of the input signal forming circuit (8), and the capacitor C1, and the output terminal (12c ) is connected to the base (13e) of the switching transistor (13), and the inverting input terminal (12b) is connected to the emitter (13b) of the transistor (13).

Further, the collector (13a) and emitter (13b) of the transistor (13) are connected to the proportional valve (8) and the resistor R5, respectively.

According to the proportional valve drive circuit (2) having the above configuration, when the phototransistor (10) is turned off by the light emitting diode (1B) described later, the resistor R1
As a result of charge being accumulated in the capacitor Cr via ~R4, the potential Vl at the output end of the input signal forming circuit (8) rises due to a time constant determined from these values, and this potential V! The proportional valve drive current I increases until the potentials of the inverting input terminal (12b) and the inverting input terminal (12b) become equal, and the proportional valve (6)
The opening degree of becomes larger. On the other hand, when the phototransistor (10) is in the on state, the capacitor C! As a result, the potential V1 at the output terminal of the input signal forming circuit (8) increases with a time constant determined by the capacitor C+ and the resistor R4.
As a result, the drive current also decreases, and the opening degree of the proportional valve (6) also decreases.

On the other hand, the proportional valve control circuit (4) converts the commercial power source (1) to, for example, direct voltage of 1i24V using the transformer (3), the rectifier circuit (14), and the smoothing capacitor C3, and uses this as a power source. This proportional valve control circuit (4) includes a pulse signal generation circuit (16), a switching transistor (17)
and a light emitting diode (18) which will be described later.

The pulse signal generation circuit (16) has a built-in microcomputer, etc., and determines the opening/closing amount to be operated for the proportional valve (6) from various input signals, and based on this determined value, the proportional 3F (8)
), for example, the pulse signal generating circuit (16) generates a pulse signal P to control the proportional valve (6) in order to control the proportional valve (6) using the duty ratio of the pulse signal. A pulse corresponding to the opening/closing value to be operated, that is, when increasing the opening degree of the proportional valve (6), use a pulse with a short width of "HI" time, and conversely, decreasing the opening degree of the proportional valve (θ). At this time, a long-width pulse of "old" time is generated at a constant cycle.The pulse signal P output by this pulse signal generation circuit (!6) is input to the base (17c) of the switching transistor (17). , this transistor (17) conducts between the collector (17a) and the emitter (+7b) over each pulse intensity of the pulse signal P, and causes current to flow through one light emitting diode (18), thereby lighting it up.

This light emitting diode (18) and the above-mentioned phototransistor (lO) are constituted by a photocoupler (20), and the phototransistor (lO) is in an on state while the light emitting diode (18) is lit. Thus, the phototransistor (10) is in an on state throughout the pulse intensity of the pulse signal P output from the pulse signal generation circuit (16), and the photocoupler (20) constitutes a signal transmission means in the present invention.

The operation of this embodiment described above will be briefly explained below.

First, when the microcomputer determines that the opening degree of the proportional valve (6) should be increased to 5 degrees based on various input conditions, the pulse signal generation circuit (16) outputs the output as shown in Fig. 2 (a). In order to reduce the duty ratio of the pulse signal P, its pulse width TI is reduced. Accordingly, the time during which the switching transistor (17) is turned on becomes shorter, and the lighting time of the light emitting diode (18) also becomes shorter. Therefore, the time that the phototransistor (10) in the proportional valve drive circuit (2) is in the ON state is shortened, the amount of charge accumulated by the capacitor C1 is large, and the potential v1 at the output end of the input signal forming circuit (8) is The height increases as shown in Figure (b). Therefore, the opening degree of the proportional valve (6) is increased by the action of the current control circuit (7) as described above.

On the other hand, on the other hand, the microcomputer uses a proportional valve (
6), the pulse signal generating circuit (16) increases the duty ratio of the pulse signal P, contrary to the above, as shown in FIG. 4(a). In order to do so, the pulse width T1 of 7 is increased. Therefore, in this case, the time period during which the phototransistor (lO) is in the on state becomes longer through the same process as described above, and the potential V1 becomes lower as shown in FIG. 3(b). Therefore, the proportional valve drive circuit becomes smaller, and the opening degree of the proportional valve (8) becomes smaller.

Although one embodiment of the present invention has been described above, the present invention is not limited to the embodiment. For example, the signal transmission means may be replaced with a photocoupler and may use a relay switch, a transformer, etc. .

Other configurations are also not limited to the embodiments.

(Effects of the Invention) As is clear from the above description, according to the present invention, the proportional valve can be driven and controlled by using the power source of the proportional valve control circuit and the power source of the proportional valve drive circuit as separate power sources, so that the proportional valve For example, it can be driven by commercial power without using a transformer, and the transformer required for the proportional valve control circuit can be reduced to one, thereby easily making the entire circuit smaller and lighter.

According to the present embodiment, the duty ratio of the proportional valve can be controlled using a substantially direct current through the actions of the capacitor C1, the current control circuit (7), etc., so that the proportional valve can be driven stably.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a proportional valve drive control circuit according to the implementation side of the present invention, and FIGS. 2 and 3 are diagrams showing signals for each part, (a)
4 is a diagram showing the pulse signal P, (b) is a diagram showing the potential Vl, and FIG. 4 is a diagram showing the prior art. In the drawings, (2) is a proportional valve drive circuit, (4) is a proportional valve control circuit, (8) is a proportional valve, (7) is a current control circuit,
(8) is an input signal forming circuit, (lO) is a phototransistor, (16) is a pulse signal generating circuit, (18) is a light emitting diode, and (20) is a signal transmission means (photocoupler).

Claims (2)

[Claims] (1) A proportional valve that opens in proportion to the magnitude of the drive current;
a proportional valve drive circuit comprising: a current control circuit connected to the proportional valve and determining the drive current based on an input signal thereof; and an input signal forming circuit forming the input signal in the current control circuit; A proportional valve control circuit equipped with a pulse signal generation circuit that generates a pulse signal having a pulse intensity corresponding to the opening/closing amount to be operated at a constant cycle, and a dual circuit between the proportional valve drive circuit and the proportional valve control circuit. and a control signal transmission means that is provided while electrically insulating the current control circuit and causes the input signal forming circuit to form an input signal in the current control circuit in accordance with the pulse intensity. control circuit. (2) The control signal transmission means includes a light emitting diode provided on the output side of the pulse signal generation circuit in the proportional valve control circuit, and a phototransistor provided in the input signal forming circuit in the proportional valve drive circuit. 2. The proportional valve drive control circuit according to claim 1, wherein the proportional valve drive control circuit is constituted by a photocoupler.