JP2924370B2 - Flow control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control valve for controlling a flow rate of a fluid.

[0002]

2. Description of the Related Art Conventionally, there has been a flow control valve of this type as shown in FIG. 6, a valve having a coil 1, a plunger 2 that slides inside the coil 1, a first spring 3 that urges the plunger 2 in a direction to push the plunger 2 out of the coil, and an inflow path 4 and an outflow path 5 Today 6
And a cylinder 7 that slides inside the valve housing 6. The cylinder 7 has a plurality of adjustment holes 8 and is interlocked with the plunger 2. The flow rate of the liquid flowing toward the center from the circumferential direction of the cylinder 7 is adjusted by the area of the adjusting hole 8 of the cylinder 7 facing the inflow path 4. A piston 10 which is a pressure receiving body 9 provided in the cylinder 7 and a valve body 11 which constitutes an opening to the outflow passage 5
And the valve shaft 12 are integrally formed. A back pressure chamber 14 partitioned from the primary chamber 13 of the inflow passage 4 while leaking slightly from the periphery of the piston 10, and the valve shaft 12 is connected to the back pressure chamber 14 and the outflow passage 5 downstream of the valve element 11. A communication hole 16 communicating with the secondary chamber 15 is provided. The piston 10 is urged in a direction in which the valve body 11 contacts the corresponding valve seat 17.
Spring 18 is provided. A pilot valve 19 for opening and closing the communication hole 16 is provided on the back pressure chamber 14 side in the valve shaft 12, and the pilot valve 19 is connected to the plunger 2.

When the coil 1 is energized, the plunger 2 is attracted against the urging force of the first spring 3 and the pilot valve 19 lifts to open the communication hole 16. At that time, back pressure chamber 1
4, the piston 10 is pushed up against the second spring 18 due to the pressure difference between the back pressure chamber 14 and the primary chamber 13, and at the same time, the valve element 11 separates from the valve seat 17 and the outlet path 5 Is formed. When the energization of the coil 1 is further increased, the lift amount of the pilot valve 19 increases, the cylinder 7 is lifted, and the adjusting hole 8 of the cylinder 7 faces the inflow passage 4 and flows from the circumferential direction of the cylinder 7 toward the center. The flow rate of the flowing fluid starts to increase, that is, by changing the current value flowing through the coil 1, the change in the lift amount of the cylinder 7 becomes a change in the area where the adjustment hole 8 of the cylinder 7 faces the inflow path 5, It adjusts the flow rate.

[0004] As shown in FIG.
When the current I is supplied to the small AC signal ΔI, the driving current is I + ΔI. This is to reduce the hysteresis characteristic of the magnetic circuit including the coil 1 and the plunger 2 and the sliding resistance at the start of driving.

[0005]

However, in the above configuration, a small amount of the alternating current is always superimposed on the coil current. For this reason, the flow control valve may overshoot, generate vibration or hunting due to the superimposed small AC signal due to the characteristics and flow rate of the flow control valve, and furthermore, the pressure and the like.

The present invention solves such a conventional problem. When the current value to the electromagnetic force generating means is changed, the output of the AC signal generating means is superimposed on the drive signal for a predetermined time. A first object is to operate a flow control valve at high speed and with low power consumption.

A second object of the present invention is to stably operate the flow control valve by superimposing the output of the AC signal generating means on the drive signal at regular intervals during the operation of the flow control valve.

[0008]

In order to solve the above-mentioned problems, a flow control valve according to the present invention comprises an electromagnetic force generating means, a valve housing having an inflow path and an outflow path, and an urging force of the electromagnetic force generation means. A valve body for adjusting the flow rate inside the valve casing, a control means for adjusting the drive current of the electromagnetic force generating means, a setting means for setting the flow rate, and a small AC signal to the drive current output by the control means. When the control means changes the current value to the electromagnetic force generating means by the signal of the setting means, the control means superimposes the signal of the AC signal generating means and after a predetermined time elapses This superposition
And a valve control means for stopping the operation .

In order to further solve the above-mentioned problems, a flow control valve according to the present invention comprises an electromagnetic force generating means, a valve housing having an inflow path and an outflow path, and the valve housing having an urging force of the electromagnetic force generating means. A valve body for adjusting the flow rate inside, a control means for adjusting the drive current of the electromagnetic force generating means, a setting means for setting the flow rate, and an AC signal for superimposing a minute AC signal on the drive current output by the control means The control means comprises valve control means for superimposing the signal of the AC signal generating means on the output of the control means at predetermined intervals of a predetermined time.

[0010]

With the above arrangement, when the current value to the electromagnetic force generating means is changed by the signal of the setting means, the signal of the AC signal generating means is superimposed on the drive signal for a predetermined time .
Also, the signal of the AC signal generating means is superimposed on the output of the control means at regular intervals.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a flow control valve, and the same parts as those in FIG. 6 are denoted by the same reference numerals, detailed description thereof will be omitted, and different parts will be mainly described.

The coil 1 and the plunger 2 form an electromagnetic force generating means 21. The flow rate is detected by the flow rate detecting means 23. 22 is a setting means for setting the flow rate.

FIG. 2 shows an example of the control means 20. Reference numeral 24 denotes valve control means for calculating the drive amount of the flow control valve from the signals of the setting means 22 and the flow rate detection means 23. Means 26 are AC signal generating means for inputting the signal of the valve control means 24 and generating a minute AC signal to be superimposed on the drive signal.

Next, the operation of the configuration of the present invention will be described. The flow rate is adjusted by the current flowing through the electromagnetic force generating means 21 as described in the background art. The control means 20 receives the signal from the flow rate detecting means 22 and the signal from the setting means 23 so that the flow rate becomes the set flow rate.
The amount of flow of the fluid is adjusted by changing the area of the adjusting hole 8 of the cylinder 7 facing the inflow path 4 by varying the amount of current flowing through the cylinder 7 and changing the lift amount of the cylinder 7.

When a current is applied to the coil 1 to operate the cylinder 7, if a minute AC signal is always superimposed, the cylinder is driven by a minute AC signal which is heavier due to the characteristics, flow rate, and pressure of the flow control valve. 7 goes too far,
Vibration and hunting may occur. Further, power is additionally required for the superposition of the minute AC signal.

Therefore, the present invention employs the following means to prevent the above phenomenon. When the setting value of the flow rate is changed by the setting means 22, the valve control means 24
This signal is received to adjust the current to the electromagnetic force generating means 21. At that time, the valve control unit 24 outputs a signal to the AC signal generation unit 26, and the AC signal generation unit 26 superimposes the minute AC signal on the drive signal only when the drive signal changes.

For example, when the valve control means 24 inputs a signal for changing the flow rate from the setting means 22 at the time t1 in FIG. 3, the driving amount is calculated, the signal is transmitted to the driving amount setting means 25, and the AC signal generating means is provided. Signal to 26. The output signal of the normal drive amount setting means is as shown by I in FIG. The AC signal generation means 26 receives the signal from the valve control means 24 and superimposes a minute AC signal on the drive signal for a predetermined time as shown by ΔI in FIG.
5 to send a small signal. As a result, the drive signal becomes like I + ΔI in FIG. Similarly, when the flow rate increases or decreases as at times t2 and t3, the minute AC signal is superimposed.

By this operation, the output of the AC signal generating means 26 is superimposed on the drive signal only when the current value to the electromagnetic force generating means 21 is changed, so that the flow control valve can be operated with low power consumption. Further, when the flow rate is changed, the flow control valve is easily moved by the minute AC signal, and the flow rate can be changed at a high speed.

FIG. 4 shows another embodiment of the present invention.
This will be described with reference to FIG. In FIG. 4, when the set value of the flow rate is changed by the setting means 22, the valve control means 24 receives this signal from the setting means 22, and receives the signal from the electromagnetic force generating means 21.
Regulate the current to the. At that time, the valve control unit 24 outputs a signal to the AC signal generation unit 26, and the AC signal generation unit 26 superimposes the minute AC signal on the drive signal only when the drive signal changes. Further, the valve control means 24 also outputs a signal to the timer means 27. The timer means 27 starts operating when the valve control means 24 sends a signal for changing the flow rate to the drive amount setting means 25, and outputs a signal to the valve control means 24 every time a predetermined time elapses. When the signal from the timer means 27 is input, the valve control means 24 outputs a signal to the AC signal generating means 26 and superimposes a minute AC signal on the drive signal.

For example, when the flow rate is changed, the drive amount is calculated when the valve control means 24 inputs a signal for changing the flow rate from the setting means 22 at times t1, t2 and t3 in FIG. The signal is sent to the drive amount setting means 25 and a signal is sent to the AC signal generating means 26. The output signal of the normal drive amount setting means is as shown by I in FIG. The AC signal generation means 26 receives the signal from the valve control means 24 and superimposes a minute AC signal on the drive signal for a predetermined time as shown by ΔI in FIG.
5 to send a small signal. As a result, the driving signal becomes I in FIG.
+ ΔI. Further, when the flow rate is changed, the timer means 27 starts to operate for a certain period of time (here, T time).
A signal is sent to the valve control means 24 every time. When this signal is input, the valve control means 24 outputs a signal to the minute AC signal generating means 26. As a result, the minute AC signal generating means 26
A small AC signal ΔI is generated every time.

The position of the flow control valve is changed at the time of changing the current value to the electromagnetic force generating means 21 by this operation and at the time of normal operation to superimpose the output of the AC signal generating means 26 on the drive signal at regular intervals. At the time of correction, the valve is always easily operated by the minute AC signal, and the flow control valve can be operated stably. Further, since the minute AC current is not always superimposed by a fixed amount, the flow control valve does not generate vibration or hunting due to the minute AC signal.

[0022]

As described above, the flow control valve of the present invention superimposes the output of the AC signal generating means on the drive signal for a predetermined time only when changing the current value to the electromagnetic force generating means. The flow control valve can be operated with low power consumption. Further, when the flow rate is changed, the flow control valve is easily moved by the minute AC signal, and the flow rate can be changed at a high speed.

Also, since the output of the AC signal generating means is superimposed on the drive signal at regular intervals during the operation of the flow control valve, the valve is always operated by the minute AC signal when correcting the position of the flow control valve. Since it is in an easy state, it is possible to operate the flow control valve stably.

Further, since the minute AC current is not always superimposed by a constant amount, the flow control valve does not vibrate or hunt due to the minute AC signal.

[Brief description of the drawings]

FIG. 1 is a sectional view of a flow control valve according to an embodiment of the present invention.

FIG. 2 is a control block diagram of the flow control valve.

FIG. 3 is an output characteristic diagram of the control means.

FIG. 4 is a control block diagram of the second embodiment.

FIG. 5 is an output characteristic diagram of the control means of the second embodiment.

FIG. 6 is a sectional view of a conventional flow control valve.

FIG. 7 is an output characteristic diagram of a conventional control means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coil 2 Plunger 4 Inflow path 5 Outflow path 20 Control means 21 Electromagnetic force generation means 23 Setting means 26 AC signal generation means

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuo Kidouchi 1006 Ojidoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-60-57079 (JP, A) (58) Survey Field (Int.Cl. ⁶ , DB name) G05D 7/06 F16K 31/06 340

Claims (2)

(57) [Claims] An electromagnetic force generating means, a valve housing having an inflow path and an outflow path, a valve body for adjusting a flow rate inside the valve housing by the urging force of the electromagnetic force generating means, Control means for adjusting the drive current of the means, setting means for setting the flow rate, and AC signal generating means for superimposing a minute AC signal on the drive current output by the control means, wherein the control means is a signal of the setting means. A flow control valve having valve control means for superimposing a signal of the AC signal generating means when changing a current value to the electromagnetic force generating means and stopping the superimposition after a predetermined time has elapsed . 2. An electromagnetic force generating means, a valve housing having an inflow path and an outflow path, a valve body for adjusting a flow rate inside the valve housing by an urging force of the electromagnetic force generating means, and the electromagnetic force generating means. Control means for adjusting the drive current of the means, setting means for setting the flow rate, and AC signal generation means for superimposing a small AC signal on the drive current output by the control means, wherein the control means is for a predetermined period of time. A flow control valve having valve control means for superimposing a signal of the AC signal generation means on an output of the control means every time.