JP2004092754A - Solenoid valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and properly set the time of carrying current to an attracting coil using a simple control system, in a solenoid valve comprising two electromagnet coils. <P>SOLUTION: An attracting cable run 4 provided with an attracting coil 5 and a holding cable run 6 provided with a holding coil 7 are provided to be parallel-connected to a coil feed line 3 comprising one switch 8 which conducts open/close movements based on valve-open/valve-close commands, and a drive circuit 11 comprising a field-effect transistor 12 and a capacitor-resistor coupled circuit 13 is mounted in the attracting cable run 4. The current is carried to the attracting coil 5 for a set time by the capacitor and resistor of the drive circuit 11. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a two-coil solenoid valve using a coil of an electromagnet as a suction coil and a holding coil, and more particularly, to a solenoid valve provided with a drive circuit capable of setting an energization time to the suction coil extremely easily.
[0002]
[Prior art]
An electromagnetic valve that attracts a valve body by electromagnetic force to open or shut off a fluid passage attracts the valve body by energizing a coil of an electromagnet as an actuator and holds the valve body at a predetermined suction position. For example, in a normally-closed solenoid valve, in addition to the weight of the valve body and the plunger and the spring load of the valve-closing spring, the pressure difference between the front and rear of the valve body and the frictional resistance of the sliding portion are overcome to attract and open the valve. Therefore, depending on the valve diameter and the primary side pressure, a considerably large suction force is required as compared with the holding force.
[0003]
For this reason, if a single coil is used to perform suction and holding, unnecessary large current flows at the time of holding, which causes inconveniences such as power consumption and high-temperature heat generation.Therefore, two coils are provided and one of them is sucked. There is provided an electromagnetic valve using an electromagnet for holding and another for holding as an actuator.
[0004]
FIG. 3 is a diagram schematically showing a general electric circuit of an electromagnet having two coils, in which a coil power supply line 52 having a suction electric circuit 53 and a holding electric circuit 54 in parallel is connected to a power supply 51, A suction coil 55 and a switch 57 are provided in a suction electric circuit 53, and a holding coil 56 and a switch 58 are provided in a holding circuit 54. The switches 57 and 58 use switches, relays, or transistors, and perform opening and closing operations in accordance with instructions from the control unit 59.
[0005]
For example, when a valve opening command is given to a normally closed solenoid valve, the control unit 59 closes the switch 57 of the suction electric circuit 53 to energize the suction coil 55, excites the electromagnet, and moves the valve body to the valve opening position. Let it be sucked. When a sufficient amount of time has elapsed for suction to the valve opening position, the control unit 59 closes the switch 58 of the holding circuit 54 and energizes the holding coil 56, while the switch 57 of the suction circuit 53 closes. To stop the energization of the suction coil 55, and the electromagnet excited by the holding coil 56 holds the valve body at the valve opening position, that is, the suction position. Alternatively, when a valve opening command is given, the two switches 57 and 58 are closed simultaneously to suck the valve body to the valve opening position, and when a sufficient time for suction has passed, the switch of the suction electric circuit 53 is opened. Open 57. When a valve closing command is given, the switch 58 of the holding circuit 54 is opened to demagnetize the electromagnet.
[0006]
[Problems to be solved by the invention]
In the conventional electric circuit, dedicated switches 57 and 58 are provided for the suction coil 55 and the holding coil 56, respectively, and these switches are opened and closed by a control unit 59, and the suction circuit 53 is opened by a timer. Since the opening and closing are performed according to the command or the closing command of the holding circuit 54 in addition to this, it is unavoidable that the whole becomes complicated and large, and the control unit 59 which is a driving circuit is assembled and integrally mounted. And could not be used as a convenient solenoid valve for transportation, installation and inspection. Further, the time required for suction is extremely short even if a sufficient time is taken from the start to completion of suction, and there is a system in which a timer capable of setting an appropriate time must be used.
[0007]
According to the present invention, the conventional electric circuit, in which the control unit with a timer controls two switches to open and close as required to control all of the suction and holding of the valve body and the opening and closing of the valve, is provided. The present invention has been made in order to solve the above-mentioned problems, and has a simple and small size as a whole, and particularly facilitates setting of an exciting time, that is, an attraction time of an attraction coil, and is integrated with a solenoid valve. The object is to provide a possible drive circuit.
[0008]
[Means for Solving the Problems]
The present invention relates to an electromagnetic valve in which the coil of the electromagnet is a suction coil for sucking the valve element and a holding coil for holding the valve body at the suction position. Solved.
[0009]
That is, a coil power supply path for supplying current to the coil, a switch installed in the coil power supply path to open and close based on a valve opening command and a valve closing command, and a suction coil having a suction coil connected in parallel to the coil power supply path. A holding circuit having an electric circuit and a holding coil, and a drive circuit provided on the suction circuit to set a current supply time to the suction coil are provided. The drive circuit comprises a field effect transistor and a capacitor / resistance coupling circuit, and energizes the attraction coil for a time set by the capacitor and the resistor.
[0010]
When a switch is closed by a valve opening command for a normally closed solenoid valve or a closing command for a normally open solenoid valve, current flows through the coil power supply path, and electricity is supplied to the suction coil and holding coil to attract the valve body. Let it. A current flows through the holding circuit until the switch is opened by a valve closing command or a valve opening command, and the valve body is held at the suction position. On the other hand, the current flowing through the suction circuit is cut off when a time set in advance by the capacitor and the resistance of the drive circuit has elapsed from the start of energization.
[0011]
Therefore, by selecting a capacitor and a resistor to be used assuming a sufficient time required for suctioning the valve element, it is possible to easily and accurately set such that it can appropriately cope with an extremely short suction time in practice. Further, since the drive circuit has a simple and small structure having a timer function, it is very easy to assemble the drive circuit to form an integrated electromagnetic valve.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. An electromagnetic coil serving as an actuator of an electromagnetic valve 1 includes a suction coil 5 for sucking a valve body and a holding coil 7 for holding the valve body at a suction position. A suction circuit 4 provided with a suction coil 5 and a holding circuit 6 provided with a holding coil 7 are connected in parallel to a coil power supply path 3 connected to a power supply 2. Further, a switch 8 formed of a switch, a relay, or a transistor is provided in the coil power supply path 3. The switch 8 closes the coil feed line 3 by operating a valve opening command (or valve closing command), and opens the coil feeding channel 3 by opening the coil feed line 3 (or valve opening command). It is.
[0013]
The suction circuit 4 includes a drive circuit 11 on the ground side of the suction coil 5. As shown in FIG. 2, the driving circuit 11 includes a field effect transistor (FET) 12 and a capacitor / resistance coupling circuit (CR circuit) 13. The field effect transistor 12, which is a MOS type in this embodiment. The source S and the drain D of the field effect transistor are connected to the suction coil 5 side of the suction circuit 4 and the ground side via the switch 8, respectively.
[0014]
The capacitor / resistance coupling circuit 13 includes a circuit 14 having a resistor 15 and a capacitor 16 in series, branched from the coil upstream side of the coil feed line 3 and connected to the gate G of the field effect transistor 12, and a resistor 18. It comprises a circuit 17 branched from between the capacitor 16 of the circuit 14 and the gate G and connected to the ground side of the coil feed path 3. Circuits not directly related to achieving the object of the present invention, such as protection circuits, are not shown in the drawings.
[0015]
When the switch 8 is closed, a current flows through the coil feed path 3, and the energizing of the attraction coil 5 and the holding coil 7 excites the electromagnet to attract the valve body. On the other hand, a current also flows through the capacitor / resistance coupling circuit 13, and when a time set by the capacitor 16 and the two resistors 15 and 18 has elapsed, a reverse voltage is applied between the gate G and the drain D, and The current flowing between the source S and the drain D is cut off.
[0016]
The time required to suck the valve element from the valve closing position (or valve opening position) to the valve opening position (or valve closing position) is in the unit of millisecond, and it is assumed that the time required to reach the suction position is sufficiently long. It is very short. Such time can be arbitrarily and accurately set by the capacity of the capacitor 16 and the resistance values of the resistors 15 and 18. When the set time elapses after the switch 8 is closed and the current starts to flow through the suction circuit 4 The field effect transistor 12 functions as a circuit breaker for interrupting the flow of current in the attraction circuit 4.
[0017]
On the other hand, since the current continues to flow through the holding electric circuit 6, even if the energizing of the attraction coil 5 is stopped, the electromagnet maintains the excited state by energizing the holding coil 7, and the valve body is moved to the attraction position. Hold. When the switch 8 is opened, no current flows through the coil feed path 3, the electromagnet is demagnetized, and the valve returns to the valve closing position (or valve opening position).
[0018]
According to the present embodiment, there is one switch 8 that opens and closes so as to close and open the coil power supply path 3 based on the valve opening command and the valve closing command. It is set by the capacitor 16 and the resistors 15 and 18 of the drive circuit 11. This eliminates the need for a complicated and large-sized device for preparing a control unit with a timer to control the opening / closing operation of the two switches and a complicated control system, and also makes the field effect transistor 12 and the capacitor / resistive coupling unnecessary. The drive circuit 11 composed of the circuit 13 is a small-sized, independent component having a timer function and performing a required operation by itself, so that it can be easily assembled to the electromagnet of the solenoid valve 1 or the valve body.
[0019]
In the present embodiment, as can be easily understood from FIG. 1, the drive circuit 11 is assembled to the solenoid valve 1 and integrally provided, and therefore the whole solenoid valve is compact and convenient for transportation, installation, inspection, and the like. There is an advantage that it becomes.
[0020]
【The invention's effect】
As described above, according to the present invention in which the energization time to the attraction coil is set by the drive circuit including the field effect transistor and the capacitor / resistance coupling circuit, the energization to the attraction coil is performed by a very simple control system. The valve body can be suctioned to a predetermined suction position by appropriately performing the above operation. In addition, since the drive circuit is a small independent part having a timer function and performing required operations independently, it is possible to easily assemble the drive circuit and integrally install it to provide a convenient solenoid valve for handling.
[Brief description of the drawings]
FIG. 1 is a layout diagram showing an embodiment of the present invention.
FIG. 2 is a circuit diagram of the drive circuit of FIG.
FIG. 3 is a layout diagram of a conventional example.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 solenoid valve, 3 coil feed path, 4 suction circuit, 5 suction coil, 6 holding circuit, 7 holding coil, 8 switch, 11 drive circuit, 12 field effect transistor, 13 capacitor / resistance coupling circuit, 15 and 18 Resistance, 16 capacitor,

Claims (3)

In an electromagnetic valve in which the coil of the electromagnet is a suction coil for sucking the valve element and a holding coil for holding the valve at the suction position,
A coil power supply path for supplying a current to the coil, a switch installed in the coil power supply path and opening and closing based on a valve opening command and a valve closing command, and the suction coil connected in parallel to the coil power supply path. A holding circuit having the suction circuit and the holding coil, and a drive circuit installed in the suction circuit to set a current supply time to the suction coil,
The drive circuit includes a field-effect transistor and a capacitor / resistance coupling circuit, and is configured to energize the attraction coil for a time set by a capacitor and a resistor.
An electromagnetic valve characterized by the above. 2. The solenoid valve according to claim 1, wherein the drive circuit is assembled and integrally provided. The field effect transistor of the drive circuit passes the attraction circuit between the source and the drain, and the capacitor / resistance coupling circuit has a capacitor / resistance and is connected to a gate of the field effect transistor. 2. A circuit which is branched and has a resistance and is connected to the drain side of the attraction circuit, and the energization time to the attraction coil is set by the capacitor and the two resistors. Solenoid valve.

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