JP2000257744A - Solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solenoid valve which can use to an alternating current electric source and direct current electric source commonly and increase the attraction force at the plunger attraction time and also reduce the consumption of an unnecessary electric force. SOLUTION: In this solenoid valve 1, the control circuit for controlling the electrification to the coil 12 is provided, when the valve is opened from the valve closed state in which a valve element 27 is contacted to the valve seat 26 by attracting a plunger 17 integral with the valve element 27 to the core 16 by the electrification to the coil 12 and separating the valve element 27 from the valve seat 26. The control circuit flows the current needed to attract and hold the plunger 17 to the core 16 by repeating the electrification and electrification cut off to the coil 12, after electrifying the direct current to the coil 12 by a full wave rectification and flowing the current needed to attract the plunger 17 to the core 16 to the coil 12 for a prescribed time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve for controlling a current flowing through a coil for adsorbing and holding a plunger integral with a valve element on a core, and more particularly, to increasing an attraction force when the plunger is adsorbed and adsorbing the same. The present invention relates to a solenoid valve in which unnecessary current consumption is reduced by reducing a current flowing for holding the current.

[0002]

2. Description of the Related Art Solenoids used in solenoid valves have no change in the structure of a coil or the like irrespective of whether the drive current is direct current or alternating current, and are used in a control circuit used to connect to a power supply when energizing the coil. It only had a change. For this reason, in the conventional electromagnetic valve, a control circuit for alternating current or direct current is rearranged, and the opening and closing drive of the valve is performed by each energizing method.

[0003]

However, since a control circuit using alternating current and direct current is required, the cost of the solenoid valve is increased due to an increase in the number of different parts. In such a solenoid valve, in the case of a solenoid controlled by alternating current, the fluctuation of the generated magnetic field causes the strength of the attraction force between the plunger and the core to be unstable. Therefore, in particular, when dust is caught between the plunger and the core, the plunger separates from the core, causing chatter, which beats and generates noise. On the other hand, it has been difficult to apply a silent structure for suppressing such noise to the solenoid valve. Further, there is also a problem that the plunger is not surely attracted to the fixed core due to the clogged dust, and the current value does not decrease and the coil is burned. In addition, in the case of AC energization, the current value until the plunger is attracted to the core by suction is 1
Although it reaches 0 to 20 times, there are many losses due to the above-mentioned fluctuation of the magnetic field, so that all the current values do not work effectively.

On the other hand, in the case of direct current application, since the plunger is constant regardless of the state until the plunger is sucked and held, the unnecessary power is consumed during the suction holding. In addition, in the case of direct current conduction, a large current needs to flow to obtain a large force for attracting the plunger to the coil, but a large current flows even after being attracted and held. In addition to wasteful power consumption, the coil generates heat due to the large current, which requires care for burns and other inconveniences. Further, it is necessary to prepare a solenoid valve having a control circuit corresponding to each of the AC power supply and the DC power supply depending on the use.

[0005] In order to solve such a problem, the present invention can be used commonly for an AC power supply and a DC power supply, and provides a solenoid valve that increases the suction force during plunger suction and reduces unnecessary power consumption. The purpose is to do.

[0006]

In the solenoid valve of the present invention, the plunger integrated with the valve body is attracted to the core by energizing the coil from the closed state in which the valve body is in contact with the valve seat. An electromagnetic valve having a control circuit for controlling energization of the coil when the valve body is opened by separating the valve body, wherein the control circuit performs DC energization by full-wave rectification and adsorbs the plunger to the core. After a current required for causing the coil to flow for a predetermined time, a current necessary for causing the plunger to be attracted to and held by the core is supplied by repeatedly energizing and de-energizing the coil. Therefore, in the solenoid valve of the present invention, a current necessary for causing the plunger to be attracted to the core flows through the coil by direct current, and the plunger is attracted to the core excited by the magnetic field generated in the coil. Then, after the plunger is attracted to the core, energization / interruption to the coil is repeated, and the current flowing through the coil is controlled so that the current does not fall below a predetermined current value required to attract and hold the plunger to the core. You.
Therefore, according to the solenoid valve of the present invention, it can be used commonly for the AC power supply and the DC power supply, and when the plunger is attracted and held by the core, the current flowing through the coil is reduced to reduce unnecessary power consumption. You.

In the solenoid valve of the present invention, the plunger integrated with the valve body is attracted to the core by energizing the coil to separate the valve body from the valve seat from the closed state in which the valve body is in contact with the valve seat. A solenoid valve having a control circuit for controlling energization of the coil when the valve is opened, wherein the control circuit includes a full-wave rectification circuit unit that changes AC current to DC current and a full-wave rectification circuit unit. A power supply smoothing unit that extracts a voltage equal to or higher than a certain value from the DC power supply voltage and smoothes it, a comparison operation unit that operates to energize and de-energizes the coil, and energizes and energizes the coil by the output of the comparison operation unit A drive element for executing cutoff, a suction current indicating unit for instructing the comparison operation unit on the energization time so that the current necessary to cause the plunger to be attracted to the core flows to the coil, and a suction current holding unit for holding the plunger and the core. Current with coil An attraction / holding current instructing unit that instructs the comparison operation unit to energize and deenergize the coil so as to flow, and a drive current detection unit that executes the operations of the attraction / holding current instruction unit by the current flowing through the coil. It is characterized by having.

Therefore, in the solenoid valve according to the present invention, a current necessary for attracting the plunger to the core flows through the coil due to the direct current supplied by the full-wave rectifier circuit, and the core excited by the magnetic field generated in the coil. The plunger is adsorbed on. Then, energization and de-energization of the coil by the drive element part are operated based on the output from the comparison operation part, and after the current necessary for the plunger to be adsorbed to the core is passed and adsorbed, the energization is interrupted. The suction holding is performed by passing a current not less than a predetermined current value required for the suction holding. At that time, the energization time for flowing the current necessary for the first adsorption to the coil is determined by the adsorption current instruction unit,
The time required to energize and de-energize the coil with the current necessary for the suction and hold after the suction is determined by the suction and hold current instruction unit.
Therefore, according to the solenoid valve of the present invention, it can be used commonly for the AC power supply and the DC power supply, and when the plunger is attracted and held by the core, the current flowing through the coil is reduced to reduce unnecessary power consumption. You.

In the solenoid valve according to the present invention, the plunger integrated with the valve body is attracted to the core by energizing the coil to separate the valve body from the valve seat from the closed state in which the valve body is in contact with the valve seat. An electromagnetic valve provided with a control circuit for controlling energization of the coil when the valve is opened, wherein the control circuit includes a coil disposed between a power line and a ground line from a full-wave rectifier circuit connected to a power supply. A smoothing circuit having a zener diode and a capacitor connected in parallel with the RC circuit of a resistor and a capacitor, which is connected between a constant voltage line for flowing a constant voltage current obtained from the smoothing circuit and the ground line, And RC
A transistor circuit of a transistor having a base terminal connected to the circuit and a first resistor; a field effect transistor and a second resistor connected in series with a coil between a power supply line and a ground line; and an output to a gate terminal of the field effect transistor An operational amplifier having a non-inverting input terminal connected to a third resistor connected in parallel with the first resistor between the constant voltage line and the ground line, and an inverting input terminal connected to a capacitor between the terminal and the ground line; , A parallel circuit including a resistor connected to the second resistor and a capacitor, and having a diode for regulating a current flow on the second resistor side.

Therefore, in the solenoid valve according to the present invention, the coil is energized by the direct current through the full-wave rectifier circuit, and a current necessary for attracting the plunger to the core flows through the coil, and the coil is excited by the magnetic field generated in the coil. The plunger sticks to the core. At that time, the bias voltage to the field effect transistor is switched by the output from the operational amplifier, and the energization / interruption to the coil is operated, and the current necessary for the plunger to be adsorbed to the core is passed and adsorbed. Blocking is performed, and a current that does not fall below a predetermined current value required for suction holding is passed, and suction holding is performed. Therefore, according to the solenoid valve of the present invention, it can be used commonly for the AC power supply and the DC power supply, and when the plunger is attracted and held by the core, the current flowing through the coil is reduced to reduce unnecessary power consumption. You.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a solenoid valve according to the present invention will be described with reference to the drawings. FIG.
It is sectional drawing which shows an example of a solenoid valve. An electromagnetic valve (hereinafter simply referred to as an electromagnetic valve) 1 includes a solenoid 2 for driving the valve,
And a valve section 3 having a flow path through which fluid flows. The solenoid 2 is defined so that a coil 12 is wound around a cylindrical coil bobbin 11, and the periphery thereof is surrounded by a yoke 13. The solenoid 2 is formed in a resin case 14 and a nut 15 is attached to the resin case 14.
The core 16 fixed at the position is inserted into the coil bobbin 11. Coil bobbin 11, coil 12, and yoke 1
3 is molded and fixed in a resin case 14. A plunger 17 is inserted into the coil bobbin 11 from below, and is provided so as to be movable up and down. In the solenoid 2, a terminal box 18 on which a control circuit described later for controlling energization of the coil 12 is fixed to the resin case 14.

On the other hand, the valve portion 3 of the solenoid valve 1 has a body 21 integrally connected and fixed to the solenoid 2. Body 21
In the figure, an input port 22 and an output port 23 are opened at symmetrical positions on the side surface, and are connected to flow paths 24 and 25 that open to the upper surface. A valve seat 26 is provided at the opening of the flow path 25.
Is formed on the upper surface of the body 21, and the valve body 27 held at the lower end of the plunger 17 is configured to abut and separate from the valve seat 26 to open and close the valve. The solenoid valve 1 is a normally closed type in which the plunger 17 is biased toward the valve seat 26 by a spring 28 and is closed.

FIG. 2 is a diagram showing the operation concept of a control circuit for driving the solenoid valve 1. As shown in FIG. In the present embodiment, an example will be described in which a solenoid 2 that drives an electromagnetic valve 1 is operated using an AC power supply 5. The components of the solenoid 2 described below will be appropriately referred to FIG. Although the control circuit of the present embodiment can be used regardless of the AC power supply and the DC power supply, the control circuit is particularly configured so that the AC power supply is converted to a DC power supply. Thus, the coil 12 is energized by changing the AC energization by the AC power supply 5 to the DC energization via the full-wave rectification circuit unit 31, and the solenoid 2 is operated. At this time, the current flowing through the coil 12 is a current value necessary for attracting the plunger 17 to the core 16. This is because the attractive force for attracting the plunger 17 to the core 16 is proportional to the magnitude of the magnetic field, and the magnetic field is proportional to the magnitude of the current flowing through the coil 12. On the other hand, the voltage converted to DC by the full-wave rectifier circuit unit 31 is
The voltage equal to or higher than a certain value is extracted by the power supply smoothing unit 33, and the voltage applied to the comparison operation unit 34 is smoothed.

In the solenoid 2, the plunger 17 is attracted to the core 16 by energizing the coil 12.
At a predetermined timing when the attraction is completed, the attraction current instruction unit 35
, An operation signal is input to the comparison operation unit 34. And
In response to the input of the operation signal, the comparison operation unit 34 operates the drive element unit 36
Is operated to cut off the energization of the coil 12. When the solenoid 2 is de-energized, the current value of the current flowing for adsorption decreases with the inductance of the coil 12, but if the current value becomes zero, the plunger 17 falls. . Then, subsequently, an operation signal is input from the attraction current instructing section 37 to the comparison operation section 34, and a low current necessary for attraction and holding flows through the coil 12. In this low-current driving, the operation of the driving element unit 36 is performed by the comparison operation unit 34 in response to the input of the operation signal of the attraction current instructing unit 37, so that the coil 12 is energized and energized so that the current value does not become lower than necessary for the attraction and holding. The interruption is repeatedly executed. As described above, the coil 12 is energized and de-energized in order to perform the attraction and the attraction and holding of the solenoid 2. At this time, the drive current detection unit 38 causes the comparison calculation unit 34 and the operation of the suction holding current instruction unit 37 are executed.

FIG. 3 is a circuit diagram showing a control circuit mounted in the terminal box 18 of the solenoid valve 1. The control circuit is
A full-wave rectifier circuit section 31 for converting an AC component into DC is connected to the AC power supply 5. The full-wave rectifier circuit unit 31 is configured by a diode bridge circuit including diodes 51, 52, 53, and 54. And the full-wave rectifier circuit unit 3
Between the power line 50 and the ground line 70 connected to
The power supply smoothing unit 33 and the solenoid 2 are connected in parallel. The coil 12 and the flywheel diode 55 are connected in parallel to the solenoid 2. On the other hand, in the power supply smoothing unit 33, a diode 61, a resistor 62, and a Zener diode 63 are connected in series between a power supply line 50 and a ground line 70, and a capacitor 64 is connected in parallel with the Zener diode 63. In addition, to such a power supply smoothing unit 33, an attraction current instruction unit 35 is connected to a constant voltage line 60 connected to the high voltage side of the Zener diode 63.

The attracting current instructing section 35 first includes a resistor 66,
The resistor 67 and the capacitor 68 constituting the RC circuit are:
It is connected in series between the constant voltage line 60 and the ground line 70. A transistor 69 whose emitter terminal is connected to the constant voltage line 60 is configured by connecting a resistor 73 (corresponding to a first resistor in claim 3) to the collector terminal and connecting a base terminal to the resistor 67. . Note that the transistor 6
The resistor 9 and the resistor 73 correspond to the transistor circuit described in claim 3. A resistor 71 (corresponding to a third resistor of the third aspect) and a resistor 72 are connected in series between the constant voltage line 60 and the ground line 70, and a transistor circuit is connected in parallel with the resistor 71. Is connected to the resistor 72. Subsequently, the comparison operation unit 34 of the control circuit
Is composed of an operational amplifier 75, the non-inverting input terminal of which is connected to the low voltage side of the resistor 71, and the inverting input terminal is connected to the ground line 70 via the capacitor 76. Further, the output terminal of the operational amplifier 75 is connected to the gate terminal of the field effect transistor 73 which is the driving element section 36, and is subjected to positive feedback via the resistor 77. The constant voltage line 60 is connected to the gate terminal of the field effect transistor 73 via a resistor 78.

On the other hand, the solenoid 2 has its coil 12 connected to a ground line 70 via a drive element section 36 and a drive current detection section 38. The field effect transistor 73 constituting the drive element section 36 has a gate terminal connected to the comparison operation section 34, a drain terminal connected to the coil 12, and a source terminal connected to the resistor 7 constituting the drive current detection section 38.
4 (corresponding to a second resistor of claim 3). Further, a parallel circuit of a resistor 81, a diode 82, and a resistor 83 is connected between the capacitor 76 connected to the inverting input terminal of the operational amplifier 75 and the resistor 74. The capacitor 76, the resistor 81, the diode 82, and the resistor 83 constitute the suction holding current instruction unit 37.

Thus, the control circuit having such a configuration drives the solenoid 2 to operate the opening and closing of the solenoid valve 1 with low power consumption based on the operation described above with reference to FIG.
First, the AC power from the AC power supply 5 is supplied to the full-wave rectifier circuit unit 3.
The current is rectified from an alternating current to a direct current by the one diode 51 to 54, and the direct current is supplied. Therefore, the DC power supplied via the full-wave rectifier circuit unit 31 is applied to the coil 12. At this time, since a voltage difference occurs between the contact b to which the non-inverting input terminal of the operational amplifier 75 is connected and the contact c to which the inverting input terminal is connected, a voltage is applied to the gate terminal of the field effect transistor 73. ing. Therefore, the coil 12
Current flows through the plunger 17 due to the generated magnetic field.
Is pulled up to the core 16 to perform suction. Since the electromotive force is induced by the inductance of the coil 12, the pulsating current flowing through the coil does not become zero due to the function of the flywheel diode 55. Coil 1
2 flows through the resistor 74 constituting the drive current detecting unit 38, and the capacitor 76 is charged through the parallel circuit of the resistors 81 and 83. Therefore, the contact c to which the inverting input terminal of the operational amplifier 75 is connected has the same voltage as the contact d.

On the other hand, the DC component voltage obtained from the full-wave rectifier circuit section 31 is further smoothed by the power supply smoothing section 33 and is generated on the constant voltage line 60. In the power supply smoothing unit 33, a constant voltage equal to or higher than a predetermined value is obtained by the Zener diode 63 from the pulsating power supply voltage which is converted into DC by the full-wave rectifier circuit unit 31. Further, since the pulsating current is charged by the capacitor 64 and flows to the load side (constant voltage line 60), a smooth DC voltage and current can be obtained. Then, the attracting current instruction unit 35
Then, a current flows to the capacitor 68 through the resistor 67,
Transistor 6 with base terminal biased
9 is activated, and current flows between the collector and the emitter of the transistor 69 and through the resistor 73 to the resistor 72. On the other hand, between the low voltage line 60 and the ground line 70,
A current flows through the resistors 71 and 72, and the resistors 71 and 73 of the attracting current instruction unit 35 form a parallel circuit. Therefore, the voltage value of the contact b to which the non-inverting input terminal of the operational amplifier 75 is connected is determined by the voltage drop of the resistor 71 and the resistor 73 in a parallel circuit. Then, a voltage difference is output from the operational amplifier 75 due to the voltage difference between the b contact and the c contact generated in this state, and a current flows through the field effect transistor 36, thereby flowing a current through the coil 12.

FIG. 4 is a diagram showing a change in the value of the current flowing through the coil 12. As shown in FIG. In the attraction current instruction section 35, the energization time T1 for flowing the attraction current I1 is adjusted. The attraction current I1 indicates a current value required to attract the plunger 17 to the core 16 and attract it, and the energization time T1 indicates a time until the plunger 17 is attracted to the core 16. Thus, the energization of the AC power supply 5 causes the attraction current I1 to flow through the coil 12 for the time T1. The suction current I1 is set by measuring a DC current at the maximum operating pressure when the plunger 17 is pulled up to the core 16 side. The strength of the magnetic field for obtaining the attraction force required to attract the plunger 17 to the fixed core 16 depends on the coil 1
This is because it is determined by the number of turns of 2 and the current value flowing therethrough. The energization time T1 is about 200 to 500 msec.

The current supply time T1 is set by the time constant of an RC circuit composed of a resistor 67 and a capacitor 68. That is, when the capacitor 68 is charged, the voltage value at the contact a rises and the bias voltage does not work on the transistor 69. Therefore, no current flows between the emitter and the collector of the transistor 69, and the voltage at the contact b is switched from the parallel circuit of the resistors 71 and 73 to the voltage drop of the circuit using only the resistor 71. As a result, the voltage difference between the b-contact and the c-contact disappears, the output of the operational amplifier 75 is stopped, the current flow of the field-effect transistor 73 is cut off, and the energization of the coil 12 is cut off. After the power is cut off, the current flowing through the coil 12 is discharged according to the time constant of the coil 12 and decreases along a curve as shown in FIG.
However, if the current stops flowing through the coil 12, the attracted plunger 17 separates from the core 16 and falls. Therefore, it is necessary to continue to supply the coil 12 with an amount of current necessary for holding by suction. Therefore, in the control circuit according to the present embodiment, a low current as shown in a portion P in FIG. Here, FIG.
FIG. 5 is an enlarged view of a current waveform of a holding current shown in a P part of FIG. 4.

When the current stops flowing through the resistor 74 constituting the drive current detecting section 38, the current flows from the charged capacitor 76 through the resistor 83 and the resistor 74. As a result, a voltage difference occurs between the non-inverting input terminal (b contact) and the inverting input terminal (c contact) of the operational amplifier 75, a voltage is output from the output terminal of the operational amplifier 75, and a current flows through the field effect transistor 73 again, and the coil 12 is energized. The current flowing through the coil 12 rises during the time T2 as shown in FIG. Then, in the adsorption holding current instruction unit 37, the current flows through the parallel circuit of the resistors 81 and 83, and the capacitor 76 is charged. Figure 5
Is time T2 shown in FIG. Therefore, when the capacitor 76 is charged, the voltage difference between the non-inverting input terminal (b contact) and the inverting input terminal (c contact) of the operational amplifier 75 disappears again.
The current flowing through the field effect transistor 73 is cut off, and the energization of the coil 12 is cut off. Then, a current is discharged from the charged capacitor 76 through the resistor 83. The discharge time at this time is time T3 shown in FIG.

Such energization (T2) and interruption of energization (T
3) is set according to the inductance of the coil 12. Specifically, when energization is performed, the current is set by the time constant of the RC circuit including the capacitor 76 of the attraction / holding current instruction unit 37 and the resistors 81 and 83. It is set by the time constant of the RC circuit consisting of the resistor 83 and the resistor 83. The energization time T2 is about 1 msec, and the energization cutoff time T3 is about 5 msec. Further, such a current supply is set so as to be a current I2 which is about twice the minimum holding current required for causing the plunger 17 to be sucked and held on the core 16. Therefore, the coil 12 has the time T
The energization and the energization cutoff are repeated at 2 and T3, and a low current of about I2 for sucking and holding the plunger 17 flows constantly.

Therefore, in the solenoid valve 1 of the present embodiment, the attraction current I1 is maintained until the plunger 17 is attracted to the core 16.
After the suction, a low current of the suction holding current I2 is made to flow constantly, so that unnecessary power that has been consumed during the suction holding can be reduced. In particular,
The power consumption was reduced to one third of the power consumption of the conventional AC power supply. In addition, in the case of holding by suction, the current at the time of suction can be increased while the current is low, so that a large magnetic field for causing the plunger 17 to be sucked to the core 16 can be obtained. Responsiveness could be improved. When a large current is supplied by direct current, the calorific value of the coil 12 increases, but the calorific value is suppressed because the holding current is set to a low current. Further, since the solenoid 2 is driven by direct current, the attraction force does not change with time unlike the conventional alternating current, and the vibration between the plunger 17 and the core 16 (generation of a beat) is eliminated. Further, the structure of the solenoid valve itself is not changed between AC and DC, and the embodiment has been described using the AC power supply 5, but it can also be used for a DC power supply.
Can be shared by an AC power supply and a DC power supply. Also,
The constant current driving of the current I1 at the time of suction and the current I2 at the time of holding the suction enables power-saving driving of the solenoid valve even if the power supply voltage fluctuates.

The present invention is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present invention.

Next, the technical idea grasped from the above embodiment will be described below together with its effects. (1) Even if the diameter (orifice) of the valve seat 26 is increased (compared to the conventional one), the current necessary for the diameter and the energization time are measured, and the current I1 during suction is set. Since the attraction force of the plunger 17 is increased without replacing or enlarging the coil 12, an electromagnetic valve capable of controlling opening and closing of the increased fluid flow rate can be obtained. The current I1 at the time of the adsorption can be set within a range in which the coil 12 does not burn out or short-circuit. Moreover, since the low current of the suction holding current I2 is made to flow constantly after the suction, the power consumption is small. (2) Even if the pressure of the fluid controlled by the solenoid valve is increased, the current necessary for the pressure of the fluid and the energization time are measured, and the current I1 at the time of adsorption is set.
Since the attraction force of the plunger 17 is increased without replacing or enlarging the coil 12, an electromagnetic valve capable of controlling opening and closing of a fluid at a high pressure can be obtained. (3) Even if the resilience of the biasing spring 28 is enhanced to increase the force pressing the plunger 17 against the valve seat 26, the current required to overcome the strengthened biasing spring 28, and After actually measuring the energization time, the suction operation of the plunger 17 is performed by setting the suction current I1. Therefore, even if a so-called back pressure case occurs in which the fluid pressure of the downstream output port 23 fluctuates and becomes higher than the input port 22 side, a highly reliable solenoid valve that does not erroneously open the valve is provided. can get.

[0027]

According to the present invention, when the valve body is in contact with the valve seat, the plunger integral with the valve body is attracted to the core by energizing the coil to open the valve body apart from the valve seat. An electromagnetic valve provided with a control circuit for controlling energization of the coil when the valve is operated, wherein the control circuit performs DC energization on the coil by full-wave rectification, and supplies a current necessary for attracting the plunger to the core. After flowing through the coil for a predetermined time, a current necessary for causing the plunger to be sucked and held by the core is configured to flow by repeatedly energizing and de-energizing the coil. Therefore, according to the solenoid valve of the present invention, since the current flowing through the coil can be increased to the maximum, it is possible to control the opening and closing of a high pressure or a large flow rate without increasing the size of the coil of the solenoid valve, and Even fluids with fluctuations can be controlled stably. Moreover, according to the present invention, there is provided a solenoid valve which can be used in common for an AC power supply and a DC power supply, and when the plunger is attracted and held by the core, the current flowing through the coil is reduced to reduce unnecessary power consumption. It became possible to provide.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a solenoid valve according to the present invention.

FIG. 2 is a diagram illustrating an operation concept of a control circuit that drives the solenoid valve 1.

FIG. 3 is a circuit diagram showing a control circuit mounted in a terminal box 18 of the solenoid valve 1.

FIG. 4 is a diagram showing a change in a current value flowing through a coil 12;

FIG. 5 is an enlarged view of a current waveform of a holding current shown in a P part of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solenoid valve 2 Solenoid 3 Valve part 5 AC power supply 12 Coil 16 Core 17 Plunger 18 Terminal box 26 Valve seat 27 Valve element 31 Full-wave rectification circuit 33 Power supply smoothing part 34 Comparison operation part 35 Adsorption current instruction part 36 Drive terminal 37 Adsorption holding Current indicator 38 Drive current detector

Claims (3)

[Claims] When a valve body is brought into contact with a valve seat and a plunger integrated with the valve body is attracted to a core by energization of a coil to separate the valve body from the valve seat and open the valve when the coil is energized, An electromagnetic valve provided with a control circuit for controlling energization of the coil, wherein the control circuit performs DC energization to the coil by full-wave rectification, and applies a current necessary for adsorbing the plunger to the core to the coil for a predetermined time. An electromagnetic valve, characterized in that a current necessary for causing a plunger to be attracted to and held by a core is caused to flow by repeatedly energizing and de-energizing a coil after flowing. 2. When a plunger integrated with a valve element is attracted to a core by energizing a coil from a closed state in which the valve element is in contact with a valve seat and the valve element is separated from the valve seat to open the valve, An electromagnetic valve including a control circuit that controls energization of the coil, the control circuit comprising: a full-wave rectification circuit unit that changes AC energization to DC energization; and a power supply voltage that is DC-converted by the full-wave rectification circuit unit. A power supply smoothing unit that extracts and smoothes a voltage equal to or higher than a certain value, a comparison operation unit that operates to energize and de-energizes the coil, and a drive element unit that executes energization and de-energization to the coil based on the output of the comparison operation unit And a suction current instruction unit for instructing the comparison operation unit of the energization time so that a current required to cause the plunger to be attracted to the core is supplied to the coil, and a current required for attracting and holding the plunger and the core to the coil. To coil And a drive current detection unit for executing the operations of the comparison calculation unit and the suction holding current instruction unit by the current flowing through the coil. And a solenoid valve. 3. When the valve body abuts on the valve seat and the plunger integrated with the valve body is attracted to the core by energizing the coil to separate the valve body from the valve seat and open the valve when the coil is energized. An electromagnetic valve including a control circuit for controlling energization of the coil, wherein the control circuit is connected in parallel with the coil between a power supply line from a full-wave rectifier circuit connected to a power supply and a ground line, A smoothing circuit including a diode and a capacitor, an RC circuit of a resistor and a capacitor connected between a constant voltage line for flowing a constant voltage current obtained from the smoothing circuit and the ground line, and a base terminal for the RC circuit. A transistor circuit of a connected transistor and a first resistor; a field effect transistor and a second resistor connected in series with a coil between a power supply line and a ground line; The non-inverting input terminal is connected to the third resistor connected in parallel with the first resistor between the constant voltage line and the ground line, and the inverting input terminal is connected to the capacitor between the ground terminal and the ground line. An electromagnetic valve comprising: an operational amplifier that is connected to a second resistor and a capacitor; and a parallel circuit including a resistor that includes a diode that restricts a current flow on the second resistor side.