JPH0435768B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] In order to realize a pressure control mechanism with high sensitivity and high response, and to enable application to fields that require high precision, such as balancers and pressure servo valves that utilize air pressure,
By significantly improving the exhaust mechanism, which was a drawback of conventional pressure control valves, we were able to reduce the pressure extremely quickly and with high sensitivity.

[Industrial application field]

The fields of application of air pressure range from the simple field of operating conventional cylinders to balancers for heavy objects, tension control for cloth and film, etc.
It is beginning to spread into fields that require high precision, such as high precision cylinder positioning and high precision pneumatic robots. Therefore, a highly accurate pressure control valve that can arbitrarily control the compressibility of air pressure is required. Therefore, it is necessary to improve the area of the relief part. The present invention is not limited to conventional valves, and by significantly improving the mechanism, it is possible to control both pressure rise and fall with high sensitivity, high response, and high accuracy, and it is possible to control pressure rise and fall with high sensitivity, high response, and high precision. It was designed so that it can also be applied to

[Conventional technology]

FIG. 2 is a longitudinal sectional view of a conventional pressure control valve.
To set the pressure, first operate the knob 1 to rotate the adjusting screw 2, lower the nut 3, and apply force to the set spring 4.

Then, the valve stem 6 and valve body 6v that are in contact with the diaphragm assembly 5 are pushed down against the bottom spring 7, and the high pressure fluid on the IN (inlet) side flows into chambers A and B.
It passes through the chamber and flows into the OUT (exit) side.

On the other hand, when the fluid pressure on the OUT side and in the B chamber increases, the set spring 4 is compressed via the diaphragm assembly 5. As a result, the valve body 6v is pushed up by the bottom spring 7 and closes the valve hole 8, so that the amount of high-pressure fluid flowing in from the IN side is reduced. By repeating this action,
The supply pressure to the OUT side is constant. The balance relationship at that time is approximately expressed by the following equation.

P ₂ = f/s...(1) However, P ₂ : Fluid pressure supplied to the OUT side f: Spring force applied to the set spring 4 s: Pressure receiving area of the diaphragm assembly 5 Next, in some condition, the OUT When the fluid pressure on the side rises above the set pressure _P2 , the diaphragm assembly 5 is pushed up against the set spring 4, so that the relief seat surface 9 of the diaphragm assembly 5 and the tip of the valve stem 6 are The pressure fluid in chamber B is released to the outside from the relief port 10 until the pressure reaches the set pressure _P2 .

In this way, the supply fluid is controlled by the pressure control valve to a constant pressure _P2 .

[Problem that the invention seeks to solve]

The pressure control speed is set to the set pressure P ₂ in an extremely short time when the flow flows from the IN side to the OUT side via chambers A and B, since the cross-sectional area of the passage is large. On the other hand, if the pressure on the OUT side is in some condition,
When the pressure becomes higher than the set pressure _P2 , fluid is released from the OUT side through the B chamber and the relief port 10. However, since the passage cross-sectional area of the relief port 10 is small, it usually takes a considerable amount of time to reach the set pressure _P2 , which poses a problem when used for high-speed response and high-precision pressure control.

The technical problem of the present invention is to solve these problems with conventional pressure control valves and to realize a pressure control valve structure in which the cross-sectional area of the relief port can be extremely large, so that when the pressure rises above the set pressure, the fluid The purpose is to escape in a short time and to be able to control fluid pressure at high speed and with high precision.

[Means for solving problems]

The technical means of the present invention taken to solve this problem includes a first piston 17 and a second piston 27, as shown in FIG.
The first piston 17 is slidably disposed on the outer periphery of the guide tube 15 communicating with the inlet 14, and is pressed by a pressure means such as a spring 19.

The second piston 27 is arranged to face the first piston 17 and is pressed toward the first piston 17 by a pressure means such as a spring 24.

A cylindrical shaft 22 is provided in the center of the second piston,
A control valve section is configured between the cylindrical shaft 22 and the tip of the guide tube 15. The cylindrical shaft 22 and the second
The passage 23 between the piston of
→ Passage 23 → Cylinder chamber 20 → Outlet 25.

When the first piston 17 moves away from the second piston 27, a gap is created between the two, and this gap serves as a relief valve.

[Effect]

When the pressure setting spring 19 is adjusted and the pressure is set, the first piston 17 and the second piston are pushed down by the spring 19.
Since the cylindrical shaft 22 is separated from the valve seat C at the tip of the guide tube 15, the compressed air flowing in from the inlet 14 flows into the outlet 25 side and is supplied to pneumatic equipment and the like. The compressed air flowing out from the valve seat C acts in a direction to increase the supply pressure. When the supply pressure increases, the first piston 17 is pushed up against the spring 19, and the second piston approaches the valve seat C, acting in the direction of narrowing the gap, reducing the passing flow rate, and increasing the flow rate on the outlet side. Keep the supply pressure constant. When the pressure on the outlet side falls below the set pressure _P2 again, the first piston 17 and the second piston are pushed down by the set spring 19, expanding the gap between the valve seats C, increasing the flow rate and reducing the pressure on the outlet side. enhance By repeating such operations, the outlet 25 side is always maintained at the set pressure _P2 .

For some reason, the outlet 25 side is now at the set pressure.
When the pressure becomes higher than P ₂ , the first piston 17 is pushed up by the pressure, and the cylindrical shaft 2 of the second piston is pushed up.
2 comes into contact with the valve seat C and cannot rise any further.
Therefore, only the first piston 17 rises, and the second
The relief valve part G opens away from the piston 27,
leak to the outside. Then, when the spring force becomes lower than the spring force of the set spring 19, the first piston 17 descends and the relief valve portion G closes.

〔Example〕

Next, examples will be used to explain how the pressure control valve according to the present invention is actually implemented. FIG. 1 is a longitudinal sectional view showing an embodiment of the pressure control valve according to the present invention. The upper cover 11, the main body 12, and the bottom cover 13 are integrated, an operation panel 16 is screwed into the upper half of a guide cylinder 15 communicating with the inlet 14, and an upper piston, which is a first piston, is screwed into the lower half of the guide cylinder 15. 17 is slidably mounted via a seal member 18. A set spring 19 is attached between the upper piston 17 and the operation panel 16, and presses the upper piston 17 downward.

In the cylinder chamber 20 formed in the main body 12,
A bottom piston 27 serving as a second piston is built-in and sealed with a seal member 21. This bottom piston 27 is integrally provided with a cylindrical shaft 22 in the shape of a piston rod. A through hole 23 is formed between the cylindrical shaft 22 and the bottom piston 27, and an end surface of the cylindrical shaft 22 A control valve part C is formed with the tip of the guide cylinder 15, and the bottom piston 27
The end face of the piston 17 and the end face of the top piston 17 form a relief valve G. A bottom spring 24 having a weaker spring force than the set spring 19 is built into the cylinder chamber 20 and presses the bottom piston 27 toward the upper piston 17 side. bottom cover 1
The outlet 25 opened in the cylinder chamber 20 and the through hole 23 of the bottom piston 27 communicate with each other via the through hole 26 opened in the cylinder chamber 20 and the main body 12.

The high pressure fluid on the IN side cannot flow to the OUT side when the valve seat C at the tip of the guide cylinder 15 and the bottom piston 27 are in contact with each other. If you now rotate the operation panel 16 and strengthen the spring force of the set spring 19, the top piston 17 will move to the bottom piston 27.
is pressed down against the bottom spring 24, the valve seat C opens and the high pressure fluid on the IN side flows into chamber D and E.
After passing through the room and F room, it flows to the OUT side. On the other hand, the pressure fluid in the D chamber pushes up the top piston 17 against the set spring 19, so the bottom piston 27 is also pushed up by the bottom spring 24 and tends to come into contact with the valve seat C, causing the supply of high pressure fluid from the IN side. quantity decreases. By repeating this operation, compressed air at a constant pressure is constantly supplied from OUT.

The balance relationship in this case is as in the case of Fig. 2, P ₂ = f/s (2) where P ₂ : Fluid pressure supplied to the OUT side f : Spring force applied to the set spring 19 s: Pressure receiving area of the upper piston 17 Next, if the fluid pressure on the OUT side rises above the set pressure _P2 for some reason, the upper piston 17
is pushed up against the set spring 19. On the other hand, when the bottom piston 27 comes into contact with the valve seat C at the tip of the guide cylinder 15, it cannot rise any further, so only the top piston 17 rises and the OUT
The side pressure fluid passes through chambers F, E, and D, and is discharged to the outside from the relief valve G between the top piston 17 and the bottom piston 27. The area of this discharge part is the outer circumference of the bottom piston 27 (the outer diameter is D ₁ on the plate).
Then, the product (πD ₁ × δt) of πD ₁ ) and the amount of rise of the atsuppa piston 17 due to pressure increase (temporarily assumed to be δt)
Therefore, its discharge cross-sectional area is extremely large, and even if the atspa piston 17 rises by a minute amount, the pressure can be instantly discharged and returned to the set pressure _P2 .
Therefore, it was possible to create a pressure control valve with extremely high sensitivity, high response, and high accuracy.

Note that the through hole H provided in the cylindrical shaft 22 is
By guiding the high-pressure fluid on the side to the J chamber on the lower side of the cylindrical shaft 22, the IN applied to the bottom piston 27 is
It has been devised to reduce the influence of side pressure, and therefore d ₁ and d ₂ are made approximately equal.

FIG. 3 is a longitudinal sectional view showing another embodiment of the present invention. In this embodiment, the operation panel 16 and set spring 19 shown in FIG. 1 are omitted, and the upper piston 17 is built in the cylinder chamber 28 on the upper cover 11 side.
The upper piston 17 can be driven by the fluid pressure supplied from the boat 29, and is configured as a pilot type pressure control valve using an external pressure signal.

In the embodiment, the pressure control valve is vertical, but it goes without saying that it can be made horizontally or upside down.

〔Effect of the invention〕

As described above, according to the present invention, since the relief port can be enlarged when the pressure on the outlet side rises above the set pressure, pressure control when the pressure rises above the set pressure can be performed in a short time, and the response is fast. Pressure control becomes possible. Also, compared to the conventional pressure control valve shown in Figure 2, the fluid flow direction and pressure adjustment knob are in the same direction, making it smaller and allowing it to be handled like a part of the piping. becomes.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a pressure control valve according to the present invention, FIG. 2 is a longitudinal sectional view of a conventional pressure control valve, and FIG. 3 is a longitudinal sectional view showing another embodiment of the present invention. FIG. 4 is a plan view of the pressure control valve of FIG. 1. In the figure, 15 is a guide cylinder, 17 is an upper piston, 19 is a set spring, 22 is a cylindrical shaft, 24 is a bottom spring, 25 is an outlet, 27
indicates the bottom piston, C indicates the valve seat (control valve section), and G indicates the relief valve section.

Claims (1)

[Claims] 1. A first piston 17 that slides in the axial direction is disposed on the outer periphery of a guide cylinder 15 that communicates with the inlet 14, and a pressurizing means for setting pressure is used to press the second piston 27.
The second piston 27 is arranged to face the first piston 17, and the second piston 27 is pressed against the first piston 17 side by a pressurizing means weaker than the pressure setting pressurizing means. The structure is such that the first piston 17 and the second piston 27 are pressed against each other.
A relief valve part G is formed between the second piston 27 and the cylindrical shaft 22 is provided in the center of the second piston 27 so as to move integrally with the cylindrical shaft 22 and the tip of the guide cylinder 15. A pressure control valve comprising: a control valve portion formed between the cylindrical shaft 22 and the second piston 27; and a passage between the cylindrical shaft 22 and the second piston 27 communicating with the outlet 25.