JP3074701B2 - Flow control valve - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a flow control valve for controlling a flow rate of a fluid according to the present invention.

2. Description of the Related Art FIG. 5 shows a conventional flow control valve of this type.

In FIG. 5, 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 to the outside, and an inflow path 4 and an outflow path 5 is provided. There is a housing pair 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 serving as a pressure receiving body 9 provided in the cylinder 7, a valve body 11 forming an opening to the outflow passage 5, and a valve shaft 12 are integrally formed. The primary chamber of the inflow passage 4 while slightly leaking from around the piston 10
The back pressure chamber 14 separated from the valve 13 and the valve shaft 12 are provided with a communication hole 16 for communicating the back pressure chamber 14 with the secondary chamber 15 connected to the outflow passage 5 downstream of the valve element 11. The piston 10 has a second spring in which the valve element 11 urges the corresponding valve seat 17 in the corresponding direction.
18 are provided. Further, a pilot valve 19 is provided on the back pressure chamber 14 side of the valve shaft 12 to open and close the communication hole 16,
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, the pressure in the back pressure chamber 14 decreases,
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 body 11 separates from the valve seat 17 to form an opening to the outflow passage 5. You.
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 path 4 and flows from the circumferential direction of the cylinder 7 toward the center. The flow rate of the starting fluid begins to increase. That is, by adjusting the value of the current flowing through the coil 1, the change in the lift amount of the cylinder 7 changes the area of the adjustment hole 8 of the cylinder 7 facing the inflow path 5, and adjusts the flow rate of the fluid.

The control means 20 superimposes a minute AC signal when a current flows through the coil 1. (FIG. 6) This is to reduce the hysteresis characteristic of the magnetic circuit composed of the coil 1 and the plunger 2 and the sliding resistance at the start of driving.

However, in the above-described configuration, since the minute AC current superimposed on the coil current is constant irrespective of the magnitude of the coil current, the flow control valve operates to operate the flow control valve. Are superimposed on the drive current. For this reason, when the coil current is changed due to the characteristics and flow rate of the flow control valve, the pressure, and the like, the flow control valve may overshoot, and vibration or hunting may occur due to the superimposed minute AC signal.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problem and provides a flow rate control for temporarily changing at least one of an amplitude and a frequency of an AC signal output from an AC signal generating means when changing a current value to an electromagnetic force generating means. An object is to operate a valve at high speed and stably.

Means for Solving the Problems In order to solve the above problems, a flow control valve of the present invention comprises an electromagnetic force generating means, a valve housing having an inflow path and an outflow path, and the urging force of the electromagnetic force generating means. A cylinder for adjusting the flow rate by sliding inside the valve housing, a control means for adjusting the drive current of the electromagnetic force generating means, a setting means for setting the flow rate, and an electromagnetic force generating means output by the control means. AC signal generating means for superimposing a minute AC signal on the drive signal of the AC signal generating means when the control means changes a current value to the electromagnetic force generating means by a signal of the setting means to change a flow rate. And a main control means for temporarily changing at least one of the amplitude and the frequency of the AC signal output from the means.

When the current to the electromagnetic force generating means is changed by the signal of the setting means in order to change the flow rate by the above configuration, at least one of the amplitude or frequency of the AC signal output from the AC signal generating means is temporarily changed. Operate the valve stably.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of the flow control valve, and the same parts as those in FIG. 4 are denoted by the same reference numerals.

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 22. 23 is a setting means for setting the flow rate.

FIG. 2 shows an example of the control means 20. 24 is the main control means,
25 is a drive current setting means, and 26 is an AC signal generation means.

 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 inputs a signal from the flow rate detecting means 22 and a signal from the setting means 23 to change the current flowing through the electromagnetic force generating means 21 so that the flow rate becomes the set flow rate, thereby changing the lift amount of the cylinder 2, and The adjustment hole 8 adjusts the flow rate of the fluid by changing the area facing the inflow path 4.

If the superimposed minute AC current is constant even when the current flowing through the coil 1 for operating the cylinder 2 is constant, when the coil current is changed due to the characteristics of the flow control valve, the flow rate, and the pressure, etc. The AC signal may cause the cylinder 2 to go too far, or cause vibration or hunting.

 Means for preventing the above phenomenon will be described below.

When the setting value of the flow rate is changed by the setting means 23, the main control means 24 receives this signal from the setting means 23 and adjusts the current to the electronic force generating means 21.

The flow control valve has slightly different characteristics depending on its shape and the like. Therefore, the sensitivity differs depending on the drive current, and the influence of the superposed AC signal is not constant.

For example, in FIG. 3, when the coil current is changed, the operation of the valve body 11 is slow and the flow rate does not readily change from Q1 to Q2 (FIG. 3 (a) (1)). When the flow rate changes from Q1 to Q2 due to the operation of the body 11, overshoot occurs (Fig. 3 (a) (2))
Etc.

Therefore, when the flow rate is changed, the valve element 11 is operated stably and quickly, so that when the flow rate is changed by the setting means 23, the main control means 24 issues a signal requesting the drive current setting means 25 to change the drive current. Together with the AC signal generating means 26
To change the amplitude and frequency of the AC signal superimposed on the drive current. The output of the AC signal generating means 26 is input to the driving current setting means 25 to be superimposed on the driving current.

For example, when the coil current is changed from I1 to I2, the valve body 11
The case where the operation is slow and the flow rate does not readily change from Q1 to Q2 (FIG. 3 (a) (1)) will be described.

When the drive current is changed (point T1 in FIG. 3 (b)), the main control means 24 outputs a signal to the AC signal generation means 26 to increase the amplitude of the superimposed small AC signal. With this, the electromagnetic force generating means
The current flowing through 21 becomes large, and the electromagnetic force generated causes the valve
11 works fast too. Since the current flowing through the electromagnetic force generating means 21 only temporarily exceeds the current I2 for maintaining Q2, the valve body 11
It doesn't go too far even if you work quickly.

When the coil current changes from I1 to I2, the valve 11
Is operated (FIG. 3 (a) (1)) when the flow rate is overscheduled.

When the drive current is changed (point T1 in FIG. 3 (c)), the main control means 24 outputs a signal to the AC signal generation means 26 to reduce the amplitude of the superimposed small AC signal. With this, the electromagnetic force generating means
The current flowing through 21 becomes smaller, and the operation of valve body 11 is reduced by the generated electromagnetic force. Although the current flowing through the electromagnetic force generating means 21 changes only slowly from I1 to I2, the flow rate can be changed stably without overshooting because the sensitivity of the valve body 11 is high.

As described above, the amplitude of the AC signal to be superimposed when the flow rate is changed by the signal of the main control means 24 can be freely changed. Therefore, the valve element 11 can be operated stably and quickly to superpose the most efficient AC signal.

In the above embodiment, only the amplitude of the AC signal to be superimposed is changed.
May change simultaneously. Also, when the flow rate is reduced, the minute AC signal is similarly adjusted.

When the set value of the flow rate is changed by the setting means 23 at the point T1 as shown in FIG. 3 (c), the main control means 24 receives this signal from the setting means 23 and outputs the AC signal generating means.
Stop generating 26 AC signals. Thereafter, at point T2, the current value of the drive current generating means 25 is changed. After the current value changes, the main control means 24 outputs a signal to the AC signal generation means 26 to adjust the superimposed small AC signal so as to start from point T2.

As a result, when the flow rate of the superimposed minute AC signal is changed, the operation is temporarily stopped for a sensitive valve, and the control algorithm is simplified.

FIG. 4 shows a second embodiment. FIG. 4 (a)
Fig. 4 (b) shows the time change of the current value, and Fig. 4 (b) shows the time change of the current derivative. A method of adjusting the drive current of the electromagnetic force generating means 21 when changing the flow rate by the setting means or when matching the signal of the flow rate detecting means 22 with the flow rate set by the setting means 23 will be described below.

First, when the drive current is reduced, the drive current is reduced when the current derivative becomes negative and large. (Fig. 4 (x)
(Point) When the drive current is increased, the drive current is increased when the current derivative becomes positive and large. (Fig. 4 (y)
As a result, the plunger and the valve element vibrate minutely due to the minute AC signal, so that when the drive current is changed at a point where the acceleration of the vibration is large (the point where the absolute value of the current derivative is large), the valve element operates at high speed. be able to.

Further, when a highly sensitive valve element is used, the valve element operates stably if the drive current is changed at the time when the current differentiation is zero (point (z) in FIG. 4).

In the above-described embodiment, the coil and the plunger are used as the electromagnetic force generating means. However, a configuration using a coil and an iron core may be used, and a magnet may be provided in the cylinder to transmit the urging force in a non-contact manner.

Further, when changing the drive current, the main control means 24 determines the difference between the current before the change (FIG. 3 (a) I1) and the current which maintains the flow rate changed by the setting means 23 (FIG. 3 (a) I2). Therefore, at least one of the amplitude and the frequency of the AC signal generating means 26 is changed in accordance with the condition (2), and the driving can be performed with higher efficiency. Further, since the phenomenon at the time of changing the flow rate is detected by the flow rate detecting means 22, when the following of the valve becomes slow, the response time can be adjusted by increasing the minute AC signal or the like.

Effect of the Invention As described above, the flow control valve of the present invention slides inside the valve housing by the electromagnetic force generating means, the valve housing having the inflow path and the outflow path, and the urging force of the electromagnetic force generating means. A cylinder for adjusting the flow rate, a control means for adjusting the drive current of the electromagnetic force generating means, a setting means for setting the flow rate, and a minute AC signal output from the control means to the drive signal to the electromagnetic force generating means. AC signal generating means for superimposing a signal, wherein the control means changes the current value to the electromagnetic force generating means according to the signal of the setting means to change the flow rate. And a main control means for temporarily changing at least one of the amplitude and the frequency of the AC signal. When the flow rate is changed, if the flow rate is changed by the setting means, the AC signal generating means superimposes the AC on the driving current. To temporarily change the amplitude and frequency of the signal,
The AC signal to be superimposed on the drive current can be changed, and the most efficient AC signal can be superimposed, and the valve element can operate stably and quickly.

In addition, by temporarily stopping the superposed minute AC signal when the flow rate is changed, the operation of a sensitive valve can be stabilized, and the control algorithm can be simplified.

Furthermore, even if the characteristics of the valve change due to aging or the like, the phenomenon can be detected by the flow rate detecting means, and the output of the minute AC signal generating means can be changed to improve the response.

[Brief description of the drawings]

FIG. 1 is a sectional view of a flow control valve according to an embodiment of the present invention, and FIG.
Fig. 3 is a control block diagram of the flow control valve, Fig. 3 is an output characteristic diagram of the control means, Fig. 4 is an output characteristic diagram of the control means of the second embodiment, and Fig. 5 is a conventional flow control valve. Sectional view of the sixth
The figure is a conventional AC signal characteristic diagram. DESCRIPTION OF SYMBOLS 1 ... coil, 2 ... plunger, 3 ... 1st spring, 4 ... inflow path, 5 ... outflow path, 6 ... valve housing, 7
... Cylinder, 9 ... Pressure receiving body, 11 ... Valve body, 12 ... Valve shaft, 14 ... Back pressure chamber, 16 ... Communication hole, 18 ... Second spring, 19 ... Pilot valve, 20 ... control means, 21 ... electromagnetic force generation means, 23 ... setting means, 26 ... AC signal generation means.

Continued on the front page (72) Inventor Yukio Nagaoka 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yasuo Kidouchi 1006 Oji Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 56) References JP-A-60-10078 (JP, A) JP-A-1-229180 (JP, A) JP-A-1-193486 (JP, A) JP-A-1-307578 (JP, A) JP-A-56-38606 (JP, A) JP-A-62-49084 (JP, A) JP-A-62-288784 (JP, A) Full-scale application Sho-57-193468 (JP, U) (58) Fields investigated (Int) .Cl. ⁷ , DB name) F16K 31/06-31/11

Claims (1)

(57) [Claims] An electromagnetic force generating means, a valve housing having an inflow path and an outflow path, a cylinder for adjusting a flow rate by sliding inside the valve housing by an urging force of the electromagnetic force generating means, Control means for adjusting the drive current of the electromagnetic force generating means, setting means for setting the flow rate, and AC signal generating means for superimposing a minute AC signal on a drive signal to the electromagnetic force generating means output by the control means. The control means temporarily changes at least one of the amplitude and the frequency of the AC signal output from the AC signal generating means when changing the current value to the electromagnetic force generating means by the signal of the setting means to change the flow rate. A flow control valve having a main control means that changes gradually.