JPH0553653A - Pressure control valve - Google Patents

Abstract

PURPOSE:To provide a pressure control valve which can control the pressure With high accuracy. CONSTITUTION:A valve housing 1 is provided with an input port 2, an output port 3, and an exhaustion port 4, and these ports 2-4 are connected to each other via a path 5. The path 5 includes a supply valve body 8, an exhaust valve body 9, and a displacement transmission rod 16. A diaphragm 15 is fixed to the rod 16 and separates a control pressure room 18 from a feedback room 19, and the rod 16 is displaced by the counteraction of pressure caused between both rooms 18 and 19 via the diaphragm 15. Then both bodies 8 and 9 are closed with displacement of the rod 16. A back pressure path 22 is formed in the rod 16 and an open port 16a links the inside of the path 5. The path 22 functions to secure the linkage between the port 3 and a back pressure room 7a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention accommodates a supply valve body, an exhaust valve body, and a displacement transmission rod in a connection passage that connects an input port, an output port, and an exhaust port provided in a housing, and at the same time, transmits displacement. A pressure receiving body is connected to one end of the rod, the neutral state where both valve bodies and their valve seats are joined together, the supply valve body and its valve seat are separated, and the exhaust valve body and its valve seat are separated. Displacement transmission between the displacement transmission rod and both valve bodies so that the supply state to be joined and the supply valve body and its valve seat are joined and the exhaust valve body and its valve seat can be switched to an exhaust state in which they are separated from each other The present invention relates to a pressure control valve that sets a relationship and controls the displacement of the displacement transmission rod by pressure opposition between the pressure of the control pressure chamber via the pressure receiving body and the output pressure of the feedback chamber communicating with the output port side.

[0002]

2. Description of the Related Art A pressure control valve of this kind is disclosed in Japanese Utility Model Publication No. 3-189.
No. 72 publication. In this conventional device, a dynamic pressure passage hole is provided in the exhaust valve body, and the back pressure chamber defined by the exhaust valve body and the output port side are communicated by the dynamic pressure passage hole.
When the supply valve body is open, the input air flows from the space between the supply valve body and its valve seat to the output port side, and the pressure (dynamic pressure) of this flow air flows through the dynamic pressure passage hole into the back pressure chamber. Act on. This dynamic pressure acts on the exhaust valve body as a back pressure to prevent the exhaust valve body from opening (blowing) when the supply valve body is open.

[0003]

The inventor of the present application has found that when the supply valve body is opened, the pressure in the vicinity of the pressure receiving surface of the exhaust valve body fluctuates depending on the opening degree of the supply valve body, that is, the flow rate. It has been found that the pressure in the chamber also fluctuates. The fluctuation of the pressure received in the exhaust valve body tends to increase as the flow rate increases, and the fluctuation of the back pressure also tends to increase, but the fluctuation of the pressure received and the fluctuation of the back pressure do not match. Due to such a discrepancy between the received pressure and the back pressure, it is not possible to reliably prevent the reduction of blow-through in the exhaust valve.

An object of the present invention is to provide a pressure control valve capable of providing such blow-through prevention.

[0005]

Therefore, according to the present invention,
A back pressure chamber is defined by an exhaust valve body, the feedback chamber and the back pressure chamber are shut off, and a back pressure introducing passage that connects the back pressure chamber and the output pressure region on the output port side is provided in the displacement transmission rod. Provided.

[0006]

By providing the back pressure introducing passage in the displacement transmitting rod, the opening position of the back pressure introducing passage with respect to the output pressure region on the output port side can be selected along the length direction or the circumferential direction of the displacement transmitting rod. By setting the opening of the back pressure introducing passage at a position where the back pressure in the exhaust valve body produces a pressure distribution that exceeds the received pressure, blow-through in the exhaust valve body is reliably prevented. The back pressure introducing passage is opened at a position where the back pressure in the exhaust valve body is lower than the pressure receiving pressure, and the pressure difference is lower than the spring force of the exhaust valve body return spring housed in the back pressure chamber. By setting, the open / close response of the exhaust valve body is improved, and the control accuracy of constant output pressure is improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will now be described with reference to FIGS.
Description will be given based on FIG. 7. An input port 2, an output port 3 and an exhaust port 4 are formed in the valve housing 1, and the ports 2, 3 and 4 are connected by a connection passage 5. The connection passage 5 connects the input port 2 and the output port 3
They are arranged opposite to each other. A lower lid 6 and an upper lid 7 are fitted and housed in the connection passage 5, and the lower lid 6 is provided with a supply valve body 8
Is slidably fitted, and an exhaust valve body 9 is fitted and housed in the upper lid 7.

An accommodation chamber 6a of the lower lid 6 for accommodating the supply valve body 8
The return spring 10 is housed in the valve, and the supply valve body 8 is biased toward the valve seat 11 by the return spring 10. The storage chamber 6a is connected to the connection passage 5 via the through hole 8a on the supply valve body 8.
And the output pressure on the output port 3 side is stored in the storage chamber 6a.
Will be introduced to.

A housing chamber 7a of the upper lid 7 for housing the exhaust valve body 9
The return spring 12 is housed in the exhaust valve body 9, and the exhaust valve body 9 is biased toward the valve seat 13 by the return spring 12. A cover 14 is joined to the upper lid 7, and a diaphragm 15 is interposed between the upper lid 7 and the cover 14. A displacement transmission rod 16 is fixed to the diaphragm 15, and one end of the displacement transmission rod 16 penetrates the upper lid 7 and projects into the connection passage 5. The displacement transmission rod 16 slidably penetrates the exhaust valve body 9 and reaches the vicinity of the pressure receiving surface 8b of the supply valve body 8. An engagement ring 17 is provided on the circumferential surface of the displacement transmission rod 16.
Is fastened. The engagement ring 17 is engageable with the pressure receiving surface 9 a of the exhaust valve body 9, and the distance from the end of the displacement transmission rod 16 in the connection passage 5 to the engagement ring 17 is the valve seat 1.
It is slightly shorter than the interval of 1,13. That is, if the displacement transmission rod 16 moves to the lower lid 6 side in the state of contacting the pressure receiving surface 8a of the supply valve body 8, the supply valve body 8 separates from the valve seat 11, and the engagement ring 17 causes the exhaust valve body 9 to move. If the displacement transmission rod 16 moves to the upper lid 7 side while being engaged with the pressure receiving surface 9a of the above, the exhaust valve body 9 separates from the valve seat 13.

One of the pair of chambers 18, 19 defined by the diaphragm 15 is connected to the input port 2 via a pressure reducing valve and a passage 20 (not shown), and the other chamber 1
9 is connected to the output port 3 side via the passage 21.
That is, the chamber 18 becomes a control pressure chamber to which a constant pressure is supplied, and the chamber 19 becomes a feedback chamber for introducing the output pressure. The feedback chamber 19 and the accommodating chamber 7a are completely blocked by the seal 23 from leaking pressure along the circumferential surface of the displacement transmitting rod 16.

The pressure of the control pressure chamber 18 and the feedback chamber 1
The pressure of 9 is opposed via the diaphragm 15, and the displacement transmission rod 16 is displaced by the opposition of both pressures. Due to this displacement, both the valve bodies 8 and 9 are closed, and the supply valve body 8 is opened and the exhaust valve body 9 is closed.
When the exhaust valve body 9 is opened and the supply valve body 8 is closed, three states are obtained: an exhaust state.

A back pressure introducing passage 22 is provided in the displacement transmitting rod 16.
Are provided in the axial direction. The back pressure introducing passage 22 opens into the accommodation chamber 7a, and further communicates with the connection passage 5 through the opening 16a on the peripheral surface of the displacement transmitting rod 16. Therefore, the pressure in the connection passage 5 is introduced into the accommodation chamber 7a through the back pressure introduction passage 22, and this introduction pressure is applied to the exhaust valve 9
Acts as back pressure on the back of the. That is, the accommodation chamber 7a becomes a back pressure chamber for the exhaust valve body 9.

Curve C in FIG.₁, C₂, C₃, C_Four, C_Five
Represents the relationship between the flow rate and the output pressure, and the output pressure curve C₁Is set
Pressure 1kgf / cm²In case of, output pressure curve C₂Is set pressure 2kgf / cm
²In case of, output pressure curve C₃Is set pressure 3kgf / cm²in the case of,
Output pressure curve C_FourIs set pressure 4kgf / cm², The output pressure curve
C_FiveIs set pressure 5kgf / cm²Is the case. Curve C₁~ C _Five
As is clear from the figure, the output pressure does not depend on the flow rate.
It is constant.

Curve D₁, D₂, D₃, D_Four, D_FiveIs exhaust
Relationship between the pressure receiving pressure Pf on the pressure receiving surface 9a of the valve body 9 and the flow rate
Represents the output pressure curve D₁Is the set pressure 1kgf / cm²If
Force curve D₂Is set pressure 2kgf / cm²In case of, output pressure curve D
₃Is set pressure 3kgf / cm²In case of, output pressure curve D_FourIs the set pressure
4kgf / cm²In case of, output pressure curve D_FiveIs set pressure 5kgf / cm ²
Is the case. Curve D₁~ D_FiveAs apparent from
The force tends to increase as the flow rate increases.

The curve E in FIG. 6 is near shown in FIG. 1, for example the opening 16a is, and represents the relationship between the pressure Pb and the flow rate in the back pressure chamber 7a when pressure force is represented by the curve D _3.
The fluctuation of the back pressure Pb in this case does not match the fluctuation of the received pressure.

FIG. 7 is a graph showing the relationship between the pressure difference obtained by subtracting the received pressure Pf from the back pressure Pb in the exhaust valve body 9 and the arrangement position of the opening 16a. The horizontal axis represents the distance L from the tip of the displacement transmission rod 16 to the opening 16a as shown in FIG. 1, and the vertical axis represents the differential pressure (kgf / cm ² ) ΔP.

The circles in FIG. 7 are the measured data when the opening 16a faces the input port 2 side as shown in FIG. 1, and the triangles show the opening 16a in the output port 3 side as shown in FIG. It is the actual measurement data when facing. The □ mark is the actual measurement data when the opening 16a faces the direction perpendicular to the input port 2 and the output port 3 as shown in FIG. The solid line connects the circles, the chain line connects the triangles, and the broken line is the squares.
It connects the marks.

As shown in FIG. 7, when the distance from the tip of the displacement transmitting rod 16 to the opening 16a is Lx, for example,
Two of each of the marks, Δ marks and □ marks are plotted, which represents the two values of the maximum differential pressure and the minimum differential pressure based on the difference in flow rate. That is, in the example shown in FIG. 6, the maximum differential pressure is ΔP.
= ΔP _max > 0, and the minimum differential pressure is ΔP = ΔP _min <0.

As shown in FIG. 2, the position of the opening 16a is the distance.
When L = 0, as is clear from the graph of FIG.
6a direction is input port 2, output port 3 and right angle direction
The differential pressure ΔP is positive regardless of the direction of
And it is almost constant, 1kgf / cm ²It is a high value above
It Such a differential pressure causes the exhaust valve body 9 and the valve seat 13 to be joined together.
To ensure that the supply valve body 8 is separated from the valve seat 11.
Of the exhaust valve body 9 due to the dynamic pressure when
Certainly prevented. Such a stable high back pressure setting
If done, the spring force of the return spring 12 can be reduced, and
The opening / closing control accuracy of the exhaust valve body 9 for force control is further improved.
It

The pressure value Ps in FIG. 7 represents the spring force of the return spring 12. To the extent that the differential pressure ΔP slightly exceeds this spring force Ps,
For example, in the range shown by H in FIG. 7, the dead zone of supply / exhaust becomes smaller. Therefore, the exhaust valve body 9 can quickly respond to a sudden change in the output pressure, and good output pressure constant control can be achieved.

As described above, the back pressure introducing passage 22 is provided in the displacement transmitting rod 16, and the opening 16a of the back pressure introducing passage 22 for the output pressure region is provided on the circumferential surface of the displacement transmitting rod 16 so that the position of the opening 16a can be adjusted. By appropriately selecting based on the differential pressure characteristic of FIG. 7, it is possible to select the pressure control according to the usage status of the pressure control valve.

Of course, the present invention is not limited to the above-mentioned embodiment. For example, a piston may be used instead of a diaphragm, and a displacement transmission rod can slide on a supply valve body as shown in Japanese Utility Model Publication No. 3-18972. The present invention can also be applied to a pressure control valve configured to be fitted in.

[0023]

As described in detail above, according to the present invention, the back pressure chamber is partitioned by the exhaust valve body, and the feedback chamber and the back pressure chamber are shut off from each other, and the back pressure chamber and the output pressure region on the output port side are separated from each other. Since the back pressure introducing passage communicating with and is provided in the displacement transmitting rod, the opening position of the back pressure introducing passage with respect to the output pressure region on the output port side can be selected along the length direction or the circumferential direction of the displacement transmitting rod. By this selection method, there is an excellent effect that blow-through prevention or high output pressure constant control can be achieved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment embodying the present invention in a case where an opening of a back pressure introducing passage faces an input port side.

FIG. 2 is a vertical cross-sectional view in the case where the opening of the back pressure introducing passage is at a position at a distance of zero from the tip of the displacement transmission rod.

FIG. 3 is a vertical cross-sectional view of a main part when the opening of the back pressure introduction path faces a direction perpendicular to the input port and the output port.

FIG. 4 is a longitudinal cross-sectional view of a main part when the opening of the back pressure introduction path faces the output port side.

FIG. 5 is a graph showing a relationship between an output pressure, a receiving pressure and a flow rate.

FIG. 6 is a graph showing the relationship between the received pressure and the back pressure.

FIG. 7 is a graph showing the relationship between the differential pressure between the received pressure and the back pressure and the distance from the tip of the displacement transmission rod to the opening of the back pressure introduction passage.

[Explanation of symbols]

1 ... Valve housing, 2 ... Input port, 3 ... Output port, 4 ... Exhaust port, 5 ... Connection passage, 7a ... Back pressure chamber, 8
... Supply valve body, 9 ... Exhaust valve body, 11, 13 ... Valve seat, 15 ...
Diaphragm as pressure receiving body, 16 ... Displacement transmission rod,
16a ... Opening, 18 ... Control pressure chamber, 19 ... Feedback chamber, 22 ... Back pressure introducing passage.

Claims (3)

[Claims] 1. A supply valve body, an exhaust valve body, and a displacement transmission rod are housed in a connection passage that connects an input port, an output port, and an exhaust port provided in a housing, and a pressure is received at one end of the displacement transmission rod. A neutral state in which the bodies are connected and both valve bodies and their valve seats are joined together; and a supply state in which the supply valve body and its valve seat are separated from each other, and the exhaust valve body and its valve seat are joined, A displacement transmission relationship is set between the displacement transmission rod and both valve bodies so that the supply valve body and its valve seat are joined and the exhaust valve body and its valve seat are switchable to an exhaust state in which they are separated from each other. In a pressure control valve for displacement control of the displacement transmission rod by pressure opposition between the pressure of the control pressure chamber via the pressure receiving body and the output pressure of the feedback chamber communicating with the output port side, the back pressure chamber is partitioned by the exhaust valve body. Together with the above A pressure control valve, characterized in that a back pressure introducing passage is provided in the displacement transmitting rod, which shuts off the feedback chamber and the back pressure chamber and connects the back pressure chamber and the output pressure region on the output port side. 2. The pressure control valve according to claim 1, wherein the opening of the back pressure introducing passage for the output pressure region is set at a position that provides a pressure distribution such that the back pressure in the exhaust valve body exceeds the pressure receiving pressure. .. 3. The opening of the back pressure introducing passage for the output pressure region is provided with a return spring for an exhaust valve body in which a pressure received by the exhaust valve body exceeds the back pressure and the pressure difference is contained in the back pressure chamber. The pressure control valve according to claim 1, wherein the pressure control valve is set to a position that provides a pressure distribution that is lower than a spring force.