JPH0524523B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a pilot pressure reducing valve having a pilot valve equipped with a nozzle flapper mechanism.

Prior Art As shown in FIG. 5, a pilot type pressure reducing valve having a pilot valve equipped with a nozzle flapper mechanism is known as, for example, the IR series precision pressure reducing valve manufactured by SMC.

In this valve, the movement of the diaphragm 51 causes
A flapper 52 of the pilot valve opens and closes the nozzle 53, varying the pressure in the diaphragm chamber 54. At this time, fluid is supplied to the diaphragm chamber 54 from the inlet port (primary side chamber) 57 via the flow path 55 and the fixed throttle 56, and the fluid passes through the opening nozzle 53 to the secondary side chamber 60 via the flow path 59. It flows out into the feedback chamber 58 which is in communication. When the pressure in the diaphragm chamber 54 increases, the diaphragm 5
1 descends, the main valve body 61 descends, and the primary side chamber 57
and the secondary side chamber 60 are opened. If the secondary side pressure rises too much, the diaphragm 51 will rise against the force of the spring 62, and the flapper 52 will close the nozzle 53.
Since the diaphragm chamber 54 is opened, the pressure in the diaphragm chamber 54 decreases. As a result, the drive diaphragm 63 rises, and the main valve body closes between the primary chamber 57 and the secondary chamber 60. When the pressure in the secondary chamber 60 rises too much, the exhaust diaphragm 64 rises and opens the exhaust valve 65.
The fluid is discharged from the exhaust port 66.

In this type of pressure reducing valve, in order to improve sensitivity and responsiveness, the nozzle/flapper part of the pilot valve is made large, and the flow rate of the pilot valve part that drives the main valve body 61 is increased to increase the gain of the pilot valve part. It is necessary to increase it. However, looking at the characteristics of this type of pressure reducing valve in a high frequency range, it is possible to accumulate the output flow of the pilot valve section in the diaphragm chamber 54 in which the diaphragm connected to the main valve body 61 is housed, or to discharge it from the diaphragm chamber 54. As a result, the opening degree of the main valve body 61 changes, and the main valve body 61 responds in the form of a delay in filling and discharging the pilot valve output pressure due to time integration of the pilot valve flow rate and the like. For example, if we consider an example in which the flapper opening of the pilot valve changes in a sinusoidal manner due to input, the flow rate of the pilot valve in the diaphragm chamber 54 also changes in a substantially sinusoidal manner. However, since the pilot valve flow rate fills and discharges the diaphragm chamber 54, and the main valve body 61 is opened and closed according to the pressure change in that chamber, the pressure change to the main valve body 61 is equal to the integral value of the pilot valve flow rate. handle. Therefore, the opening degree of the main valve pair 61 changes simply in the form of a cosine wave, which is an integral value with respect to a sine wave. In other words, the phase of the opening of the main valve body lags the phase of the flapper opening of the pilot valve by a maximum of 90 degrees. Similarly, the pressure change in the secondary chamber 59 of the main valve, that is, the pressure change in the feedback chamber 62, with respect to the opening degree of the main valve body 61 corresponds to the integral value with respect to the change in the opening degree of the main valve body. The pressure response of the secondary chamber 59 of the main valve lags the opening degree of the main valve element by up to 90 degrees. Based on the change in the flapper opening of the pilot valve, the secondary side chamber 5 of the main valve is opened via the change in the opening of the main valve.
9, that is, a feedback pressure change occurs, but this change is ultimately the sum of the phase delay in the opening degree of the main valve body 61 and the phase delay in the pressure change in the secondary side chamber 59.

For this reason, the phase of the pressure in the secondary side chamber, that is, the phase of the feedback pressure, is delayed by 180 degrees at most with respect to the opening degree phase of the flapper. If delay elements such as friction are added to this, the phase delay of the feedback pressure becomes closer to 180°, and the phase of the feedback pressure becomes in phase with the input, so the system becomes a divergent body.

A pilot type pressure reducing valve with characteristics in the high frequency range as described above becomes stable when the gain of the pilot valve section is small because the amplitude becomes sufficiently small until the response delay reaches 180 degrees, but when the gain is If it increases, there is a problem in that a hunting state occurs in which disturbance or the like becomes a driving force and continues self-transmission.

In the conventional pressure reducing valve described above, it is unavoidable that the feedback pressure has a phase delay of up to 180° with respect to the displacement of the flapper. Therefore, it is impossible to avoid the risk of a hunting situation occurring.

Purpose The present invention aims to solve the above-mentioned conventional problems and provide a pilot type pressure reducing valve that does not cause oscillation.

Configuration The present invention achieves the above-mentioned objects by: an inlet port, a primary side chamber communicating with the inlet port, an outlet port, a secondary side chamber communicating with the outlet port, and a space between the primary side chamber and the secondary side chamber. a main valve body having a main valve seat formed in the main valve seat and a pilot pressure chamber, a main valve body that can be seated on the main valve seat, and a main valve body that is connected to the main valve body by a valve stem and that is connected to the secondary side chamber and the pilot a drive member that is arranged in a sealed and movable manner so as to form a boundary between the pilot pressure chamber and the pilot pressure chamber; a pilot valve portion that opens into the pilot pressure chamber; and a nozzle flapper mechanism that adjusts the pressure of the pilot valve portion. . A pilot pressure reducing valve having a feedback passage connecting the secondary side pressure chamber to the pilot valve portion, wherein the pilot valve portion is connected to a pilot valve body formed as the flapper;
It has a feedback chamber connected to the feedback flow path with the pilot drive member in between, and a drive chamber provided on the opposite side of the feedback chamber, the drive chamber being open to the outside through a throttle,
This is achieved by a pilot type pressure reducing valve characterized in that the fluid in the pilot pressure chamber can flow into the drive chamber when the flapper opens.

Effect According to the present invention, when the pilot valve body is clogged and the flapper opens the pilot pressure chamber, the discharge fluid flows from the pilot pressure chamber into the drive chamber. It acts as a back force against the feedback pressure on the drive member. This back pressure has the effect of reducing the phase lag of the feedback pressure, and thus has the effect of preventing the phase lag of the feedback pressure from becoming 180° with respect to the fluctuating phase of the flapper.

Embodiments The details of the structure and operation of the present invention will be explained based on embodiments shown in the drawings.

In Fig. 1, the main valve body 1 has an inlet port 2.
, a primary side chamber 3 communicating with the inlet port 2, an outlet port 4, and a secondary side chamber 5 communicating with the outlet port 4.
, a valve seat 6 formed between the primary chamber 3 and the secondary chamber 5, and a pilot pressure chamber 7.

A main valve body 8 can be seated on the valve seat 6, and a driving member 10 is connected to the main valve body 8 by a valve rod 9.

The drive element 10 is, for example, designed as a diaphragm, as shown in FIG. 1, in which case the pilot pressure chamber 7 forms a diaphragm chamber. In another example, the drive element 10 can be designed as a piston, in which case the pilot pressure chamber 7 is designed as a piston chamber.

A port 12 of a pilot valve 11 opens into the pilot pressure chamber 7. The pilot valve 11 has a pilot valve body 14 that can be seated on a pilot valve seat 13 provided in the port 12. Pilot valve body 1
4 is connected to a pilot drive member 16 by a valve stem 15. The pilot drive member 16 is the drive means 1
7, the pilot valve body 14 is pressed against the pilot valve seat 13. The driving means 17 is accommodated in a spring chamber 19 which is formed in the pilot body 18 and serves as an adjustment pressure chamber that accommodates the pilot driving member 16. The driving means 17 includes a spring 20 whose one end is pressed against the pilot driving member 16, and a spring 20 which is housed in the spring chamber 19. 20
The spring seat 21 whose other end is articulated, and the pilot body 1
8 and adjust the position of the spring seat 21 to remove the spring 2.
Includes a pressure adjustment screw 22 for adjusting zero force.

The pilot drive member 16 is shown as a diaphragm, but it can also be designed as a piston.

The surface of the pilot drive member 16 opposite to the surface on which the drive means 17 acts faces a feedback chamber 23, which is connected to the
It communicates with the next chamber 5, and pressure fluid from the second chamber 5 is introduced therein.

The pilot valve 11 is a nozzle flapper mechanism 2
5. The nozzle flapper mechanism 25 has a flapper made of the pilot valve body 14 itself that opens and closes the port 12, and a fixed nozzle 26. The fixed nozzle 26 has a flapper that opens and closes the port 12.
an inlet passage 2 connecting the fluid source or the primary chamber 3;
It is formed as part of 7. The discharge fluid passing through the port 12 opened and closed by the flapper 14 is discharged through the discharge passage 2.
8 into the spring chamber 19 and exerts a force on the pilot drive member 16 that is opposite to the force of the feedback chamber 23. The spring chamber 19 is opened to the outside through a throttle 29, and the discharge fluid of the nozzle flapper mechanism is discharged to the outside through the throttle 29. In the example shown in FIG. 1, the discharge passage 28 is formed as a passage passing through the valve stem 15.

The pilot fluid passes through the inlet passage 27 to the nozzle 2.
6 into the diaphragm chamber 7, pressure is applied to the pilot valve pair (flapper) 14 and the drive member 10.
Act _P2 .

When the pressure P ₁ in the secondary chamber 5 is below a predetermined pressure, the pilot drive member 16 presses the pilot valve pair 14 against the valve seat 13 by the force of the drive means 17 and holds the port 12 closed. There is. Therefore, the pressure _P2 in the diaphragm chamber 7 pushes the drive member 10, and the main valve body 8 separates from the valve seat 6, opening the valve seat 6. As a result, the fluid at the pressure P ₀ in the primary chamber 3 flows into the secondary chamber 5, and the pressure P ₁ in the secondary chamber increases.

The pressure fluid in the secondary chamber 5 is transferred to the feedback chamber 23.
Since the pressure _P3 in the feedback chamber 23 increases, the pressure in the feedback chamber 23 increases.
When P ₃ reaches a predetermined pressure, the pilot drive member 16
is pushed against the force of the drive means 17, and the pilot valve body 14, or flapper, is moved to open the port 12.
opens. As a result, the fluid in the diaphragm chamber 7 is discharged to the outside through the spring chamber 19, the drive member 10 returns, and the main valve body 8 closes the valve seat 6.

If the flapper 14 is configured so that when it falls in the direction of the arrow as the position When increasing the output pressure, the spring chamber 19
Since fluid does not flow into the spring chamber 19 but rather tends to exit through the throttle 29, the back pressure generated in the spring chamber 19 tends to decrease. This means that the back pressure is in opposite phase (±180°) to the output generated by the flapper. That is, the delay in the phase α of the pressure in the spring chamber 19 is −180°≦α ₃ ≦0°.

However, due to the displacement of the flapper 14, the spring chamber 19
There is a delay of up to 90° in the pressure change, so when these are combined, the actual phase delay of the pressure in the spring chamber 19 is −180°≦α ₃ ≦−90°, resulting in a phase that is more than 90° advanced. .

Since the acting direction of the back pressure in the spring chamber 19 is opposite to the acting direction of the pressure in the feedback chamber 23, when converted to the same direction as the acting direction of the feedback chamber 23, the phase α ₃ ' of the back pressure in the spring chamber 19 is The phase is opposite to α ₃ and is given by α ₃ +180°, and the phase delay is 0≦α ₃ ′≦90°.

Feedback pressure obtained through the main valve body,
That is, the pressure in the feedback chamber 23 and the spring chamber 1
The phase lag α ₀ α ₀ = α ₂ + α ₃ ' of _the overall feedback pressure acting on the pilot drive member, which is a combination of the back pressures of If the
Decreases in the direction of lag of 180° or less.

Figure 2 shows the pressure fluctuations in each of the above parts, where the horizontal axis shows time, the vertical axis shows pressure and the opening degree (displacement x) of the flapper, and curve A shows the change in the opening degree of the flapper. Curve B shows the variation in pressure _P3 in the feedback chamber, curve C shows the pressure variation in the spring chamber in the same direction of action as the feedback chamber, and curve D shows the pressure variation in the feedback chamber and the spring chamber. In FIG. 2, it can be seen that by applying another small feedback to the spring chamber, the phase lag of the pressure in the feedback chamber is reduced by α ₄ .

According to the present invention, by adding a small feedback in addition to the feedback caused by the movement of the main valve body, the phase delay of the pressure fluctuation acting on the pilot drive member can be made smaller than 180°, and the occurrence of self-oscillation can be prevented. It became possible.

By appropriately setting the area of the diaphragm that connects the spring chamber that adds another small feedback to the outside, the back pressure, that is, the amplitude of the small feedback can be adjusted, and the delay in the composite phase can also be adjusted.

Therefore, even if there is a delayed pressure reflection from equipment connected to the secondary side of the main valve, this adjustment can increase the back pressure and provide vibration isolation.

The modification of the present invention shown in FIG. 3 differs from the embodiment shown in FIG. 1 only in the flow path of the nozzle flapper mechanism of the pilot valve portion and the configurations of the pilot valve body and the pilot valve seat. The same or corresponding parts as in the example of FIG. 1 are given the same reference numerals, and the parts that are different from the example of FIG. 1 will be explained.

In FIG. 3, the pressing force exerted by the driving means 17 on the pilot driving member 16 separates the pilot valve body 14 from the pilot valve seat 13, thereby opening the pilot valve seat 13. Due to this change in configuration, the inflow channel 27 communicates with the port 12 at the open end on the opposite side from the diaphragm chamber 7, and as the pilot valve body 14, that is, the flapper moves open, the pilot fluid flows into the port 12. The water flows into the diaphragm chamber 7 from there.

The diaphragm chamber 7 is connected to a discharge passage 28' via a fixed nozzle 26, and the discharge passage 28 is temporarily connected to the preliminary chamber 3.
The preliminary chamber 30 is connected to the spring chamber 19 via an intermediate diaphragm 31. Compared to the example shown in FIG. 1, a preliminary chamber 30 and an intermediate diaphragm 31 are additionally provided.

When the flapper moves downward against the pressure in the feedback chamber 23 according to the force of the driving means, when the port 12 is opened, the output pressure is increased by cooperation with the fixed nozzle 26, and when the flapper is raised, the port 12 closes and the output is reduced. Pressure decreases.

The phase delay due to pressure fluctuation is caused by the diaphragm chamber 7.
As for the secondary pressure chamber 5, that is, the feedback chamber 23, 0≦α ₁ ≦90° and 0≦α ₂ ≦180°, just as in the example shown in FIG.

Regarding the discharged fluid led to the spring chamber 19, in the example of FIG. 1 there was a phase lag of 90 degrees from the flapper to the spring chamber 19, but in FIG. Preparatory room 3
0 and an intermediate aperture 31 are provided. In the preliminary chamber, the phase delay is 0≦α ₃ ≦180°, and the spring chamber 19
The back pressure at is 0≦α ₃ ′≦270°. Since the back pressure is in the opposite phase to the feedback pressure, when converted into the same direction of action as the feedback pressure, it becomes α ₃ −180°, and −180°≦α ₃ ″≦90°.

Therefore, in the combination of feedback pressure and back pressure, the phase delay is -180°≦α ₀ ≦180°. In other words, the same effect as the example of FIG. 1 can be obtained in the example of FIG. 3 as well.

FIG. 4 shows, as a modification of FIG. 3, a pusher 32 that contacts the pilot drive member 16 and pushes the pilot drive member 16, and an adjustment drive member 33 that is connected to the pusher and moves the pusher. An example is shown in which a fluid pressure drive means 17' having a diaphragm or a piston, for example, and an adjustment port 34 into which adjustment fluid for pressing an adjustment drive part 33 flows. The other parts are exactly the same as the example shown in FIG. Similarly, the first
Fluid pressure drive means 1 instead of drive means 17 in the example shown in the figure.
7' can also be used. The pressure of the pressure reducing valve can be adjusted by adjusting the flow rate or fluid pressure of the regulating fluid.

In the example shown in FIG. 3, a pressurizing chamber 19' is used as a back pressure generating chamber for feedback pressure instead of the spring chamber 19 as the regulating pressure chamber.

Effects According to the present invention, it has become possible to prevent hunting, which continues self-oscillation, with a simple structure.

The amplitude of the additional back pressure added to the feedback can be adjusted by simply adjusting the throttle area, and the pressure is reflected more slowly from the equipment connected to the secondary side of the main valve. It is now possible to measure vibration isolation by increasing the back pressure even in cases where the

By installing a volumetric system in the exhaust flow path of the nozzle flapper, for example, as a preliminary chamber, and adding one orifice, the phase can be delayed by 90 degrees, and by changing the number, it is suitable for vibration isolation against the phase delay of the main valve. Ta
It is possible to create a backpressure phase advanced by 90°.

In addition to the two-port valve having the inlet and outlet ports shown in the figure, it can also be used as a valve that has a discharge port or the like and can switch and connect the secondary side chamber to the discharge port.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a pressure reducing valve according to the present invention, and FIG.
The figure shows a pressure fluctuation state, FIGS. 3 and 4 are cross-sectional views of modified examples, and FIG. 5 is a cross-sectional view of a conventional pressure reducing valve. 1...Main valve body, 2...Inlet port, 3...1
Next side chamber, 4...Exit port, 5...Secondary side chamber, 6
... Main valve seat, 7 ... Diaphragm chamber, 8 ... Main valve body, 9 ... Valve stem, 10 ... Drive member, 11 ... Pilot valve section, 12 ... Port, 13 ... Pilot valve seat, 14... Pilot valve body (flapper), 15... Valve stem, 16... Pilot drive member, 17, 17'... Drive means, 19... Spring chamber,
23... Feedback chamber, 25... Nozzle flapper mechanism, 26... Nozzle, 27... Inflow path, 28... Outlet path, 29... Throttle.

Claims (1)

[Claims] 1. An inlet port 2, and 1 leading to the inlet port 2.
A downstream chamber 3, an outlet port 4, a secondary chamber 5 communicating with the outlet port 4, a main valve seat 6 formed between the primary chamber 3 and the secondary chamber 5, and a pilot pressure chamber 7. a main valve body 1 having a main valve body 1, a main valve body 8 that can be seated on the main valve seat, and a boundary between the secondary side chamber 5 and the pilot pressure chamber 7, which is connected to the main valve body 8 by a valve rod 9. A drive member 10 which is arranged in a sealed and movable manner so as to form a valve, a pilot valve part 11 that opens into the pilot pressure chamber 7, and a nozzle flapper mechanism 2 which adjusts the pressure of the pilot valve part 11.
5, and the secondary side pressure chamber is connected to the pilot valve section 11.
In the pilot pressure reducing valve having a feedback passage 24 connected to the flapper 14, the pilot valve portion 11 is connected to the flapper 14.
A pilot drive member 16 connected to a pilot valve body formed as a pilot valve body, a feedback chamber 23 connected to the feedback passage 24 with the pilot drive member 16 in between, and a feedback chamber 23 provided on the opposite side from the feedback chamber 23. Adjustment pressure chamber 19
The adjusting pressure chamber 19 is opened to the outside through a throttle 29, and when the flapper 14 is opened, the fluid in the pilot pressure chamber 7 flows into the adjusting pressure chamber 19.
A pilot type pressure reducing valve characterized in that it is formed to allow inflow into the air.