JPH0219845Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure control valve that can control the pressure on the fluid outlet side using an electric signal.

The conventional pressure control valve shown in FIG.
a valve seat 3 between the valve seat 3 and the fluid outlet 2;
A valve body 4 is provided coaxially with the valve body 4 , and a diaphragm 5 , a diaphragm contact plate 6 , and a permanent magnet 7 are fixed to the upper part of the valve body 4 , and the outer periphery of the diaphragm 5 is supported by a valve case 8 . The diaphragm 5 and the valve body 4 are formed so that their pressure receiving areas on the upstream side of the valve body, that is, within the primary pressure chamber 9, are approximately equal. A secondary pressure chamber 10 is located downstream of the valve body, and a flow nozzle (not shown) is connected further downstream of the fluid outlet 2. 11 is a primary pressure chamber 9 formed by a diaphragm 5
12 is a yoke fixed to the valve case 8; 1 is a communication hole for communicating the upper space partitioned with the atmosphere;
Reference numeral 3 indicates a fixed iron core provided at the center of the yoke 10 facing the permanent magnet 7, and 14 indicates an electromagnetic coil.

To explain the operation of such a conventional pressure control valve, fluid fed under pressure to the fluid inlet 1 at a predetermined supply pressure flows into the primary pressure chamber 9, and the valve body 4 and the valve seat 3
The fluid flows into the secondary pressure chamber 10 and flows into the fluid outlet 2 according to the gap between the fluid and the valve opening degree. 2 at this time
Let's take a look at the fluid pressure in the secondary pressure chamber 10, that is, the secondary pressure _P2 . First, the balance relationship of the forces acting on the valve body 4 is such that the pressure in the primary pressure chamber 9, that is, the primary pressure, is P ₁
The pressure receiving area of the diaphragm on the primary pressure chamber 9 side is
Similarly, when A _D is the pressure receiving area of the valve body and A _V is _the pressure receiving area of the valve body on the secondary pressure chamber 10 side, it is expressed by the following equation.

F + P ₁・A _V = P ₁・A _D +P ₂・A _V …(1) F is coil 14, fixed core 13, yoke 1
2. This is the force obtained by adding the weight W of the valve body 4 and the permanent magnet 7 to the magnetic force Fg caused by the permanent magnet 7, etc.

By the way, since P ₁ ·A _V and P ₁ ·A _D are formed to be approximately equal, equation (1) becomes as follows.

F= _P2・A _V ...(2) Therefore, the secondary pressure _P2 is determined by the attractive force or electromagnetic repulsion of the permanent magnet 7, regardless of the primary pressure _P1.In other words, it is determined by the electromagnetic repulsion force. Therefore, secondary pressure
P ₂ is controlled.

The characteristics of this conventional pressure control valve are shown in FIG. 2A. The horizontal axis of this characteristic diagram shows the current I flowing through the coil of the pressure control valve, and the vertical axis shows the secondary pressure _P2 . With this conventional characteristic, in order to control the secondary pressure P ₂ between 0 and _PT , the coil current I is controlled between I ₂ ' and I ₄ . However, this conventional pressure control valve has the disadvantage that variations in the characteristics of the permanent magnet 7 appear as variations in the characteristics of the pressure control valve. Further, in the conventional pressure control valve, when no electrical input is applied to the coil 14, that is, when the current is zero, an attractive force acts between the permanent magnet 7 and the fixed iron core 13, and the valve body 4 comes into contact with the valve seat 3. ing. That is, the valve is in a closed state. The secondary pressure P ₂ gradually increases the current in the coil 14, and the coil current I ₂ causes electromagnetic repulsion to begin to act between the fixed iron core 13 and the permanent magnet 7.
It finally begins to increase.

The electromagnetic force due to this coil current I ₂ is
This is the force necessary to cancel the attractive force acting between the permanent magnet 7 and the permanent magnet 7, and when reducing the operation starting current _I2 with the characteristics shown in Fig. 2A, the magnetic force of the permanent magnet 7 must be weakened. This can be achieved by However, this increases the gain of the control characteristics as shown in FIG. 2A'. In other words, the amount of change in the secondary pressure P ₂ with respect to the coil current I becomes large, and a slight variation in the coil current I results in a large change in the secondary pressure P ₂ .

When the magnetic force of the permanent magnet 7 is weakened, the fixed iron core 1
Fixed iron core 1 when permanent magnet 7 is displaced relative to 3
This is because the change characteristics of the magnetic force acting between the permanent magnet 3 and the permanent magnet 7 change, which is not practical. Therefore, the current is of no use in controlling the secondary pressure P ₂ from zero to I ₂ , and in other words, the disadvantage is that a relatively large current is required to obtain a predetermined secondary pressure. It was hot.

The present invention has been made in view of the above-mentioned conventional examples, and an object of the present invention is to provide a pressure control valve that can be operated with low electric power and has small variations in characteristics.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows a cross-sectional view of the pressure control valve according to the present invention, showing the fluid inlet 21 and fluid outlet 2 of the valve body 20.
A valve seat 23 is provided between the valve seat 2 and the valve seat 2. This valve seat 23
A valve body 24 is provided coaxially with the valve body 24, and a diaphragm 25 and a magnet seat 26 made of a non-magnetic material are provided above the valve body 24.
and a first permanent magnet 27 are attached. Further, a magnetic pole portion 29 of a fixed iron core 28 is provided opposite to the first permanent magnet 27, and a magnetic pole portion 29 of a fixed iron core 28 is provided at an upper end portion of the fixed iron core 28 in a direction that is weaker than the first permanent magnet 27 and repulsive to the first permanent magnet 27. A second permanent magnet 30 that produces a magnetic pole in the magnetic pole portion 29 is provided with a gap g formed therebetween. 31 is a yoke, 32 is an exciting coil, 3
3 is a coil bobbin, and an electromagnet is constituted by a fixed iron core 28, a second permanent magnet 30, a yoke 31, and an exciting coil 32. The second permanent magnet 30 is the yoke 3
It is suspended and fixed by an adjustment member 36 consisting of a screw 34 and a fixing nut 35 screwed into 1.
By inserting a tool such as a screwdriver into the groove 37 and rotating it, the relative position of the second permanent magnet 30 with respect to the fixed iron core 28 can be adjusted. In other words, it is possible to freely adjust the air gap g serving as a magnetic gap, and the repulsive force of the second permanent magnet 30 generated in the magnetic pole portion 29 can be adjusted.

Reference numeral 38 denotes an electromagnetic body which clamps the diaphragm 25 and is fixed to the valve body 20. Reference numeral 39 is a vent hole, and 40 is a lower cover, which is fixed to the valve body 20 through an O-ring 41 without leakage.

In the above configuration, when the excitation coil 32 is not energized, the first permanent magnet 27 and the fixed iron core 28 attract each other, the first permanent magnet 27 acts in an upward lifting direction, and the valve body 24 The valve is in a closed state. However, at this time, the force acting on the valve body 24 due to the action of the second permanent magnet 30 is smaller than when only the first permanent magnet 27 is used. For the sake of explanation, this attraction force will be referred to as Fa. Next, when the excitation coil 32 is energized, the above-mentioned attractive force Fa becomes smaller, and when the coil current is increased, the above-mentioned attractive force Fa becomes smaller.
Fa becomes zero, and when the coil current is further increased,
Fa transitions to repulsive force and the valve begins to open, and the valve opening increases in proportion to the current. A characteristic diagram of this invention is shown in curve B of FIG. The fluid outlet 22 side pressure _P2 starts to be controlled with the coil current _I1 , and the maximum control pressure is reached with _I3 .
Reach P _T. That is, pressure control is possible within the range of current I ₁ ' to _{I 3} .

In addition, since the relative position of the second permanent magnet 30 with respect to the fixed iron core 28 can be adjusted by the adjustment member 36, the first
The attractive force acting between the permanent magnet 27 and the magnetic pole part 29 can be adjusted, and the operation start current _I1 can be arbitrarily set between 0 and _I3 .

Furthermore, in the conventional example, when the operation start current is made small, it is necessary to weaken the magnetic force of the first permanent magnet 27, which causes a problem that the gain of the control characteristic becomes large, but in this example, the second permanent magnet 30 is provided. In order to reduce the attractive force acting between the first permanent magnet 27 and the magnetic pole part 29, the first permanent magnet 3
Magnetic pole part 29 and first permanent magnet 30 when 0 is displaced
The rate of change of the magnetic force acting during this period does not change significantly, and the operation start current value of the pressure control valve can be made smaller than in the conventional example without deteriorating the gain of control characteristics.

As mentioned above, the present invention replaces the second permanent magnet with the first permanent magnet.
By making the magnetic force acting between the permanent magnet and the fixed core magnetic pole part adjustable, the operation starting current value can be reduced without significantly changing the gain of the control characteristics, and operation can be performed with small electric power.

In addition, since an adjustment member is provided, the operation starting current can be increased or decreased with a simple operation, and it is possible to greatly reduce variations in the control characteristics of the pressure control valve due to variations in the characteristics of the permanent magnet, assembly errors, etc. Thus, a pressure control valve whose operation start current value can be set at an arbitrary point can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional pressure control valve, Fig. 2 is a characteristic diagram showing the relationship between coil current and secondary pressure,
FIG. 3 is a sectional view of a pressure control valve showing an embodiment of the present invention. 21...Fluid inlet, 22...Fluid outlet, 23...
...valve seat, 24...valve body, 25...diaphragm,
27...First permanent magnet, 28...Fixed iron core, 29
... Magnetic pole part, 30 ... Second permanent magnet, 31 ... Yoke, 32 ... Excitation coil, 36 ... Adjustment member.

Claims (1)

[Scope of utility model registration request] It has a valve seat provided between a fluid inlet and a fluid outlet, a valve body coaxially with this valve seat, a diaphragm and a first permanent magnet that operate in response to fluid pressure are attached to the valve body, and a first permanent magnet is attached to the valve body. A fixed iron core magnetic pole part is provided opposite to the first permanent magnet, and an excitation coil and a yoke are provided that generate a magnetic force in a direction repulsive to the first permanent magnet when energized, and the fixed iron core, the excitation coil, and the yoke are provided. a second permanent magnet forming a magnetic pole in a direction repulsive to the first permanent magnet in the fixed core magnetic pole part in a magnetic circuit consisting of; and a relative position between the second permanent magnet and the fixed core. A pressure control valve equipped with an adjustment member for adjustment.