JPH04102777A - Flow quantity control valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

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

2. Description of the Related Art Conventionally, there has been a flow control valve of this type as shown in FIG.

In FIG. 4, a valve having a coil 1, a plunger 2 that slides inside the coil 1, a first spring 3 that biases the plunger 2 in a direction to push the plunger 2 to the outside, an inflow path 4 and an outflow path 5. There is a housing 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 from the circumferential direction toward the center of the cylinder 7 is adjusted by the area of the adjustment 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
, a valve body 11 constituting an opening to the outflow passage 5, and a valve shaft 1.
2 are integrated. A back pressure chamber 14 is partitioned off from the primary chamber 13 of the inflow passage 4 while leaking slightly from around the piston 10;
A communication hole 16 is provided that communicates the two fire chambers 15 that are connected to the downstream outlet passage 5. The piston 10 is provided with a second spring 18 that biases the valve seat 17 to which the valve body 11 corresponds in the corresponding direction. Further, a pilot valve 19 is provided within the valve shaft 12 on the back pressure chamber 14 side to open and close the communication hole 16, and the pilot valve 19 is connected to the plunger 2.

When the coil 1 is energized, the plunger 2 is attracted against the biasing force of the first spring 3, and the pilot valve 19 is lifted to open the communication hole 16. At that time, the pressure in the back pressure chamber 14 decreases, and the piston 10 is pushed up by the pressure difference between the back pressure chamber 14 and the first fire chamber 13, overcoming the second spring 18.
At the same time, the valve body 11 separates from the valve seat 17 and an opening 8 to the outflow passage 5 is formed. When the energization to the coil 1 is further increased, the lift amount of the pilot valve 19 increases, and the cylinder 7 is lifted, so that the 1ii1 nodal hole 8 of the cylinder 7 faces the inflow passage 4, and the cylinder 7 moves from the circumferential direction toward the center. The flow rate of the inflowing fluid starts to increase. In other words, by adjusting the current value flowing to the coil 1, the lift amount of the cylinder 7 can be changed.
The area of the adjustment hole 8 of the cylinder 7 facing the inflow path 5 changes to adjust the flow rate of the fluid.

The control means 20 superimposes a minute alternating current signal when passing current through the coil 1. (FIG. 5) This is to reduce the hysteresis characteristic of the magnetic circuit consisting of the coil 1 and the plunger 2 and the sliding resistance at the start of driving.

Problems to be Solved by the Invention However, in the above configuration, the minute alternating current superimposed on the coil current is constant regardless of the magnitude of the coil current.

Therefore, when the coil current is small, the amplitude of the minute alternating current signal is larger than the coil current value, and the flow rate may not be reduced to a desired level, or vibration or hunting may occur.

The present invention solves these conventional problems! The purpose is to stably operate a flow rate control valve by changing the amplitude of the AC signal generating means in accordance with the current value to the magnetic force generating means.

Means for Solving the Problems In order to solve the above problems, the flow control valve of the present invention comprises: a valve body having an inflow path and an outflow path; an electromagnetic force generating means;
The valve body operates inside the valve body to adjust the flow rate using the biasing force of the magnetic force generating means, and the control means adjusts the current of the electromagnetic force generating means, and the control means uses an alternating current signal as a drive signal. The alternating current signal generating means includes an alternating current signal generating means for superimposing the above! The structure is such that the amplitude changes depending on the current value applied to the magnetic force generating means.

Effect: With the above configuration, the amplitude of the superimposed alternating current signal generating means is changed in accordance with the TK and 'lX values applied to the electromagnetic force generating means.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. Note that FIG. 1 is a sectional view of the flow control valve, and the same parts as in FIG. 4 are designated by the same numbers. Coil 1 is plunger 2
This forms the electromagnetic force generating means 21.

The flow rate is detected by a flow rate detection means 22. 23 is a setting means for setting the flow rate.

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

Next, the operation of the configuration of the present invention will be explained.

1 is replaced by magnetic force generating means 21 in the same way as explained in the conventional technology.
The flow rate is adjusted by the current flowing through the tube. The control means 20 inputs the signal from the flow rate detection means 22 and the signal from the setting means 23 to vary the current flowing through the electromagnetic force generation means 21 and change the lift amount of the cylinder 7 so that the flow rate becomes the set flow rate. The flow rate of the fluid is adjusted by changing the area of the adjustment hole 8 facing the inflow path 4.

At this time, if the current flowing through the electromagnetic force generating means 21 is a direct current, it is difficult to move the cylinder 7 quickly and adjust the flow rate due to the hysteresis characteristics of the magnetic circuit consisting of the coil 1 and the plunger 2 and the sliding resistance at the start of driving. .

Furthermore, even if an AC signal with a constant amplitude and a constant frequency is simply superimposed on the current flowing through the IIT magnetic force generating means 21, the hysteresis characteristic of the magnetic circuit and the sliding resistance at the start of driving will be reduced, but the regular AC signal will cause the valve body to 11 resonance vibration or hunting may occur.

Furthermore, when the flow rate is reduced to a small level, the flow rate adjustment may become unstable, or if the amplitude of the minute AC signal is larger than the coil current, the flow rate may not be reduced to the desired flow rate.

Means for preventing the above phenomenon will be explained below.

Flow control valves have slightly different characteristics depending on their shape and other factors. For example, the sensitivity varies depending on changes in the area of the adjustment hole 8 of the cylinder 7 facing the inflow passage 4, and the influence of the superimposed alternating current signal is not constant.

Therefore, the main control means 24 sends a signal to the AC signal generation means 26 in accordance with the output to the drive amount setting means 25 (according to the current value to the electromagnetic force generation means 21), and the AC Make the amplitude of the signal vary. The output of the AC signal generating means 26 is input to the driving amount setting means 25 in order to be superimposed on the driving signal.

For example, when the drive current is small and the flow rate is restricted, the sensitivity of the valve body is high. Therefore, as the drive current becomes smaller, the superimposed alternating current signal also becomes smaller as shown in FIG. 3(a). In a region where the flow rate is large, even if the minute alternating current signal is constant, it does not affect the sensitivity of the valve body 11 much. Therefore, when the drive current exceeds a certain value (FIG. 3 (aJ x point)), the amplitude of the minute alternating current signal may be kept constant.The combined drive current becomes as shown in FIG. 3(b).

In this way, the amplitude of the alternating current signal superimposed on the drive current can be freely changed by the signal from the main control means 24. Therefore, resonance of the valve body 11 is suppressed and the most efficient AC signal is superimposed, so that the valve body 11 can be operated stably and quickly.

In the above embodiment, only the amplitude of the superimposed AC signal is changed, but the frequency may be changed, or both the amplitude and frequency may be changed simultaneously.

Further, in the above embodiment, a coil and a plunger are used as the electromagnetic force generating means, but a structure using a coil and an iron core may be used, and a magnet may be provided in the cylinder to transmit the biasing force in a non-contact manner.

A second embodiment will be described next.

When the flow rate is completely throttled and the flow rate control valve is closed, even if the drive current is reduced to zero, a minute alternating current signal may remain and the valve body 11 may not be fully closed.

In this case, when the drive current becomes smaller than a preset value (determined by the main control means 24 or the setting means 23), the main control means 24 sends a signal to the minute AC signal generation means 26 to stop the AC signal superimposed on the drive current. . The superimposed AC signal is as shown in FIG. 3(c). Here, the drive current value set in advance is assumed to be point y in FIG. 3(c).

Therefore, when closing the flow rate control valve, as the flow rate is reduced, there is no alternating current signal superimposed on the way, so there is no vibration due to the alternating current signal or the valve body 11 is not closed, and a stable closing operation is possible.

On the other hand, when opening the flow control valve, the alternating current signal is superimposed after the drive current exceeds a certain value, so there is no instability when the valve body 11 begins to open. The combined drive current is as shown in FIG. 3(d).

A third embodiment will be described next.

When the drive current is small, if the amplitude of the minute alternating current signal is approximately equal to or larger than the magnitude of the drive current, the influence of the minute alternating current signal will be greater and the operation of the valve body 11 will become unstable.

Therefore, the minute alternating current signal generating means 26 receives the value of the drive current from the main control means 24, and generates a third signal with an amplitude smaller than this value.
An alternating current signal like the one shown in the figure (el) is superimposed.

Therefore, the drive current is small (as the influence of the minute AC signal is also reduced, the valve body 11 can stably control the flow rate at a small flow rate).

Effects of the Invention As described above, the flow control valve of the present invention includes a valve body having an inflow path and an outflow path, an electromagnetic force generating means, and an urging force of the electromagnetic force generating means to operate the inside of the valve body. The valve body that adjusts the flow rate and the above! control means for adjusting the current of the magnetic force generation means; the control means includes AC signal generation means for superimposing an AC signal on the drive signal; and the AC signal generation means adjusts the amplitude according to the current value to the electromagnetic force generation means. As the drive current becomes smaller, the superimposed minute alternating current signal also becomes smaller, so even if the flow rate is reduced to a small flow rate, the flow rate can be controlled stably.

In addition, if the AC generating means is configured to stop generating an AC signal when the current value to the electromagnetic force generating means is less than a predetermined value, the flow rate will be throttled down when the flow rate is fully throttled and the flow rate control valve is closed. Since there is no alternating current signal superimposed on the way, there is no vibration caused by the alternating current signal or the valve body is not closed, and stable closing operation is possible.

On the other hand, when opening the flow control valve, the alternating current signal is superimposed after the drive current exceeds a certain value, so there is no instability when the valve body begins to open.

In addition, if the AC generating means is configured to superimpose an AC signal with a smaller amplitude than the current value to the tm force generating means on the drive signal, as the drive current becomes smaller, the influence of the minute AC signal also becomes smaller, so that the valve body can be stably reduced. Flow rate control becomes possible.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a flow control valve according to an embodiment of the present invention, and FIG.
The figure is a control block diagram of the flow control valve, Figure 3 is an output characteristic diagram of the control means of the flow control valve, Figure 4 is a sectional view of a conventional flow control valve, and Figure 5 is a conventional AC signal characteristic diagram. It is. 1... Coil, 2... Plunger, 3
. . . ] spring, 4 . . . Inflow path, 5 . . . Outflow path, 6 . . . Valve body,
7...Cylinder, 9...Pressure receiving body, 11
... Valve body, 12 ... Valve shaft, 14 ...
...Back pressure chamber, 16...Communication hole, 18...
... Second spring, 19 ... Pyro 7) valve, 20 ... Control means, 21 ... Electromagnetic force generation means, 23 ... Setting means , 26...
- AC signal generation means. Name of agent: Patent attorney Shigetaka Awano Haka 1 person No. 21! ! Fig. ■ Fig. (6L) Fig. M

Claims (3)

[Claims] (1) A valve body having an inflow path and an outflow path, an electromagnetic force generating means, a valve body that operates inside the valve body with the urging force of the electromagnetic force generating means to adjust the flow rate, and the electromagnetic force generating means. and control means for adjusting the current of the means, the control means having an AC signal generation means for superimposing an AC signal on the drive signal, and the AC signal generation means controlling the amplitude according to the current value to the electromagnetic force generation means. Variable flow control valve. (2) The flow control valve according to claim 1, wherein the alternating current generating means is configured to stop generating the alternating current signal when the current value to the electromagnetic force generating means becomes less than a predetermined value. (3) The flow control valve according to claim 1, wherein the alternating current generating means is configured to superimpose an alternating current signal having a smaller amplitude than the current value to the electromagnetic force generating means on the drive signal.