JPH0337672B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a self-holding solenoid valve that has a permanent magnet in its magnetic circuit and is energized from an external power source only when it is necessary to operate, and does not cause any hindrance to the opening and closing operations of the valve. The purpose of this invention is to obtain a signal indicating the open/closed state of a valve without any mechanical operating parts, and to prevent incomplete operation.

Self-holding solenoid valves are used to reduce the power consumption of the solenoid valve drive circuit or to avoid generating heat from the solenoid valve, but since no power is required to maintain the open or closed state, the valve cannot be operated only from the drive circuit side. It is not possible to determine whether it is open or closed.

Therefore, in order to detect the open or closed state, means are generally used to open and close the switch in conjunction with the valve operation. Although FIG. 1 shows a conventional example, a micro switch is used here. The valve body I forms a valve seat D on the way from the inlet A to the outlet C, and a solenoid part is provided on the upper surface. A fixed iron core is formed by the U-shaped first yoke H, the flat plate-shaped second yoke H, and the magnetic pole T, and a permanent magnet H is located between the second yoke H and the magnetic pole T. The valve is supported by a movable iron core so as to be able to move up and down inside the guide tube.One end has a valve rubber corresponding to the aforementioned valve seat, and the other end corresponds to the magnetic pole. A spring is provided between the magnetic pole and the movable iron core in the direction of separation, and the attraction force is weaker than when the magnetic pole and the movable iron core are in the attracting position as shown in the figure, and the force of attraction is weaker than that when the magnetic pole and the movable iron core are wound around the coil bobbin. The spring strength is set to be stronger than the force that occurs when the coil wire is energized and the attraction force of the permanent magnet is reduced. The movement of the movable iron core is transmitted to the outside by the contact rod, and the micro switch opens and closes the electrical contacts in conjunction with the opening and closing of the valve.

When the valve is maintained in the open state due to the attractive force of the permanent magnet, if electricity is applied in a direction that reduces this attractive force even momentarily, the valve will be closed by the force of the spring, and the closed state will remain even after the electricity is cut off. Chill. At the same time, the micro switch can also be switched. When the valve is opened again, the contact rod is pulled up and attracted, and at the same time the contacts of the micro switch return to their original state.

By the way, since the self-holding solenoid valve utilizes the attractive force of a permanent magnet, there is a limit to the force of the spring that moves the movable iron core. Therefore, the influence of the seal friction of the part penetrating to the outside, such as the contact rod, and the friction caused by the force of the micro switch cannot be ignored. If the frictional force increases due to long-term use,
Even if the coil is energized, the valve may not close reliably. In addition, if the micro switch has poor contact or is installed loosely, not only will accurate signals of the valve open/close status not be obtained, but as a result, there is a danger that the valve will not close when it should. It's even possible. There is also a conventional example in which a secondary coil is provided with an AC electromagnet, and disconnection of the primary coil is detected by detecting the presence or absence of induced electromotive force in the secondary coil, but this is
This method was based on the premise that the electromagnet would operate reliably by energizing the next coil, and it was not possible to detect malfunctions due to deformation of structural parts or clogging with foreign objects.

The present invention aims to solve the above-mentioned problems associated with self-holding solenoid valves by obtaining reliable valve opening/closing signals over a long period of time without using switches that involve mechanical operation. It is. That is, a self-holding solenoid valve has a magnetic circuit consisting of a fixed iron core, a movable iron core, and a permanent magnet, and a drive/detection coil that is wound around the magnetic circuit to increase/decrease and detect the magnetic flux in the magnetic circuit, and the drive/detection coil. It consists of an excitation circuit that energizes the valve, and a detection circuit that works with the induced electromotive force of the drive/detection coil.The detection circuit has a polarity judgment circuit and a level judgment circuit for the induced electromotive force, and when the valve is operated. The operating state of the valve is detected based on the polarity and level of the induced electromotive force, and the excitation circuit is operated again when the electromotive force level is other than a preset value. This system determines whether the valve has opened or closed, and if the operation is incomplete, the excitation circuit is operated again to ensure reliable operation. be.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

FIG. 2 shows an embodiment of the present invention, in which a valve body 1 is formed with passages for an inlet 2, a valve seat 3, and an outlet 4. 1
The outer periphery is surrounded by a yoke 5 and a flat second yoke 6, and a magnetic pole 7 is placed in the center.
is taking shape. A movable iron core 9 is provided at a position facing the magnetic pole 7, and is guided and supported in the center so that it can move up and down. A permanent magnet 10 is provided between the magnetic pole 7 and the first yoke 5, and the permanent magnet 10, the movable iron core 9, and the fixed iron core 8 constitute a magnetic circuit 11. A spring 12 is biased in a direction to separate the magnetic pole 7 and the movable iron core 9. A drive coil 14 and a detection coil 15 wound around a coil bobbin 13 act on this magnetic circuit 11 . The coil bobbin 13 has a permanent magnet 10 and a magnetic pole 7
The center line of the movable iron core 9 is made to coincide with the center line of the movable iron core 9, and the vertical movement of the movable iron core 9 is guided and supported, and a fluid seal is also provided. A valve receiver 16 and a valve rubber 17 are swingably attached to the lower end of the movable iron core 9 and correspond to the valve seat 3. Further, an operation button 19 integrated with the operation shaft 18 is provided on the central lower surface of the body 1, and when pushed up, the movable iron core 9 is moved in the suction direction, thereby opening the valve. 20 is a return spring, and after operation, the operating shaft 1 is pressed so that the valve operation will not be affected.
It plays the role of pushing back 8. Further, the cover 21 prevents the operating shaft 18 from being bent due to external impact. These operating shaft 18, operating button 19, return spring 20, and cover 21 constitute an operating device 22 for manually opening the valve. In this way, the self-holding solenoid valve 23 includes the valve body 1, the magnetic circuit 11, the spring 12, the drive coil 14,
It is composed of a detection coil 15, a valve rubber 17, an operating device 22, and the like.

Next, the detection coil 15 is connected to a detection circuit 28 composed of a polarity determination circuit 24 , a level determination circuit 25 , an OR circuit 26 , and a self-holding display element 27 . On the other hand, the drive coil 14 is connected to an excitation circuit 32 having a one-shot power supply 29, a sensor 30, and an OR circuit 31.

Now, the self-holding solenoid valve 23 is the operating device 2.
2 pushes up the movable iron core 9, and when it approaches a position where the attractive force due to the magnetic flux of the permanent magnet 10 is superior to the repelling force of the spring 12, it is rapidly attracted, and thereafter the valve is in an open state. Next, when the drive coil 14 is energized in the direction of the magnetomotive force that reduces the magnetic flux of the permanent magnet 10, the attractive force becomes lower than the repelling force of the spring 12, and the movable iron core 9 is pulled at once by the force of the spring 12. The valve is then released, and the valve remains closed thereafter. The characteristics of the magnetic circuit 11 in this case are B-H of the permanent magnet.
This will be explained using FIG. 3 which shows a characteristic diagram. In the valve open state, that is, in the adsorption position, the magnetic resistance is low and the dimensional ratio line is as shown by A, and the magnetic flux density at this time is _B1 . Further, in the valve closed state, that is, in the separated position, there is a large air gap, so the magnetic resistance is high and the dimensional ratio line becomes B, and the magnetic flux density at this time is _B3 . Now,
When the drive coil 14 is energized in a direction that reduces the magnetic flux of the permanent magnet 10, and the magnetization strength is H _S , the magnetic flux density at that time is determined by the line C drawn by moving the dimension ratio line A by H _S. Then it becomes _B2 . Since the magnetic attraction force is determined by the magnetic flux density and the area of the attraction surface, the above-mentioned magnetic flux density indicates the attraction force in each state. However, since B ₃ is a separated position, it indicates the magnetic flux density of the permanent magnet 10, but does not indicate the magnetic flux density that generates an attractive force with the movable iron core 9.

As the magnetic flux density differs depending on the valve position, an electromotive force is generated in the detection coil 15 at the moment of operation from closing to opening or from opening to closing, and the polarity of the electromotive force varies depending on the direction of operation. . Now, when the operating device 22 is operated from the valve closed position to the valve open position, the magnetic flux density rapidly increases from _B3 to _B1 . If the polarity of the induced electromotive force due to this sudden change is positive, the polarity determination circuit 24 sends a signal to the self-holding type display element 27 through the OR circuit 26 to indicate that the valve is open. Therefore, when the valve opening operation is incomplete, for example when the pressing stroke is insufficient, the valve opening display does not appear, and it is possible to prompt the user to perform the valve opening operation again. Next, when the drive coil 14 is energized from the valve open state to close the valve, the magnetic flux density is
B ₁ temporarily decreases to B ₂ and then rapidly decreases to B ₃ .
The electromotive force at this time is determined to be negative, and the level determination circuit 2
At step 5, the magnitude is compared with a preset value, and if it is larger than the set value, a signal is sent to the self-holding display element 27 through the OR circuit 26 to indicate that the valve is closed. If the electromotive force value is smaller than the set value, for example, if the drive coil 14 is energized but does not close for some reason, the magnetic flux density will only momentarily decrease from _B1 to _B2 , and the amount of change will be small. . Therefore, the value of electromotive force becomes small. At this time, the one shot power supply 29 is operated again through the OR circuit 31 of the excitation circuit 32 to perform the valve closing operation once again. The sensor 30 is activated when the state of the controlled object using the self-holding solenoid valve 23 becomes abnormal, such as a temperature switch, a pressure switch, a proximity switch, etc. This sensor 3
A signal of 0 operates the one-shot power supply 29 through the OR circuit 31 to energize the valve in the valve closing direction. If a large electromotive force indicating that the valve is clearly closed is not obtained by the method described above, the valve is closed again.

The sensor 30 may be a timer or a manual switch, or may be a logic circuit that determines various phenomenon values according to predetermined procedures. The circuit also includes a noise prevention circuit, a waveform shaping circuit, etc., but these are omitted because they are not basic requirements of the present invention.

Now, FIG. 4 shows an example of the self-holding type display element 27. A valve open indicator coil 34 and a valve close indicator coil 35 are wound vertically on the coil bobbin 33, and an iron core 36 is installed in the center of the coil bobbin 33.
passes through it, and there is a yoke 37 on the outside of one side. A disk-shaped magnet 38 is placed on the upper end surface of the coil bobbin, and there is an inversion case 39 formed of a dome-shaped transparent body surrounding the disk-shaped magnet 38.
Now, when the valve is manually operated from the closed position to the open position, a valve open indication signal is sent, and the current flows to the valve open indication coil 34. Since the direction of the magnetic flux at this time is opposite to the polarity of the magnet 38 up to that point, the magnet 38 rises from the upper end of the coil bobbin 33, collides with the reversing case, reverses itself, and is attracted to the iron core 36 again and comes to rest. That is, magnet 38
The front and back sides of the figure were switched. Conversely, when a valve close indication signal is sent, the current flows through the valve close indication coil 35, and the winding direction is designed so that its polarity is opposite to that of the valve open indication coil 34. Therefore, the magnet 38, which had been stable until then, is again subjected to a repulsive force and is turned over by the reversing case 39, and comes to rest in the state shown in FIG. That is, by looking at the front or back side of the magnet 38, it is possible to determine whether the valve is currently open or closed. The self-holding type display element 27 requires electric power only at the moment when the magnet 38 is reversed, and after that, the magnet 38 remains attracted to the iron core 36 and does not reverse, so that the display can be maintained indefinitely. I can do it. Although FIG. 4 shows an example in which there are two reversely wound coils, there may be one coil and the polarity of the current according to the display signal may be reversed. Most simply, if the electromotive force of the detection coil 15 is directly applied to the coil of the display element, the polarity of the electromotive force when the valve is opened and when the valve is closed is reversed, so that a valve open or closed indication can be performed. However, in this case, it is necessary to generate the power necessary for displaying the reverse operation, so please check the coil specifications and magnet 3.
8 strength is required. In addition to the display element shown in FIG. 4, a display element that utilizes an electrochemical phenomenon to display a display even after electricity is removed can also be used in the present invention.

In addition to the configuration shown in FIG. 2, the self-holding solenoid valve 23 has the following features:
Modifications such as providing the permanent magnet 10 on a part of the first yoke 5 or on the movable iron core 9 side are also possible. or,
The drive and detection coils do not need to be split windings as shown in Figure 2; they can be wound in two layers (inner and outer), or a single coil with a tap taken out from the middle can be used to detect increases and decreases in magnetic flux and its changes. Any configuration that can be detected by induced electromotive force may be used. Furthermore, in Fig. 2, the valve is opened manually, but the polarity of the supply from the one-shot power supply 29 can be changed to enable the valve to be opened and disconnected.
It is also possible to energize and attract, and it is of course possible to detect the change in magnetic flux at that time with the detection coil 15 and display the open/closed state, or to restart the operation when the electromotive force value is small using the method described above. .

As described above in detail based on the embodiments, the present invention includes a magnetic circuit including a fixed core, a movable core, and a permanent magnet, and a drive/detection coil wound around the magnetic circuit to increase/decrease and detect the magnetic flux in the magnetic circuit. It is composed of a self-holding solenoid valve having a self-holding type electromagnetic valve, an excitation circuit that energizes the drive/detection coil, and a detection circuit that works by the induced electromotive force of the drive/detection coil, and the detection circuit is a polarity determination circuit for the induced electromotive force. It has a level judgment circuit that detects the operating state of the valve based on the polarity and level of the induced electromotive force when the valve is operated.
Since this is a self-holding solenoid valve control device that reactivates the excitation circuit when the level of electromotive force is below a preset value, it is possible to detect the valve position without any mechanical operating parts such as switches. Its reliability can be dramatically improved.

In particular, the detection circuit has a circuit that determines the polarity and level of the electromotive force, and if the electromotive force is below a predetermined level, the excitation circuit is activated again, so if it does not operate reliably, The valve can be re-energized to ensure valve closing or opening. In addition, since it is configured to display the open/closed status of the valve with a self-holding display element, not only is no electricity required to maintain the display, but when the valve is manually opened, the amount of operation is insufficient and the valve is held open. If the condition does not occur, the display does not change, which has the effect of notifying the operator of this fact and prompting him to perform the operation again.
In this way, it is possible to significantly improve the reliability of using the self-holding solenoid valve.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing valve position detection of a conventional self-holding solenoid valve, Fig. 2 is a sectional view and control block diagram of a self-holding solenoid valve according to an embodiment of the present invention, and Fig. 3 is a magnetic A B-H characteristic diagram showing the characteristics of the circuit, and FIG. 4 is a cross-sectional view of the self-holding type element. 8... Fixed iron core, 9... Movable iron core, 10... Permanent magnet, 11... Magnetic circuit, 14... Drive coil, 15... Detection coil, 23... Self-holding solenoid valve, 32... Excitation circuit, 28...Detection circuit, 2
4...Polarity judgment circuit, 27...Self-holding display element, 25...Level judgment circuit.

Claims (1)

[Scope of Claims] 1. A self-holding solenoid valve having a magnetic circuit consisting of a fixed iron core, a movable iron core, and a permanent magnet, and a drive/detection coil wound around the magnetic circuit to increase/decrease and detect magnetic flux in the magnetic circuit; It is composed of an excitation circuit that energizes the drive/detection coil, and a detection circuit that works with the induced electromotive force of the drive/detection coil.The detection circuit has a polarity judgment circuit and a level judgment circuit for the induced electromotive force, and A self-holding solenoid valve that detects the operating state of the valve based on the polarity and level of the induced electromotive force when it is operated, and that restarts the excitation circuit when the electromotive force level is below a preset value. Control device. 2. The self-holding system according to claim 1, wherein the detection circuit includes a self-holding type display element, and the self-holding type display element is driven depending on the polarity and level of the induced electromotive force to display the open/closed state of the valve. Type solenoid valve control device.