JPS6097414A - Pressure reducing valve - Google Patents

Abstract

PURPOSE:To stop pressure reducing operation when entrance side pressure exceeds a set value, and hold exit side pressure as high as the entrance side pressure by providing an intake valve which opens a back pressure intake passage when the pressure in an inflow passage exceeds the set value to the back pressure intake valve. CONSTITUTION:When pressure higher than the set value set with a compression spring 31 for releasing is applied to the inflow passage 14 of a pressure reducing valve 10, an intake piston 30 is pressed down and the back pressure intake valve 37 leaves a back pressure intake valve seat. Consequently, the pressure in the inflow passage 14 is guided to the back pressure chamber 27 behind the differential piston 13 to rough a valve chamber 19, valve seat 36, intake cylinder chamber 28, and passage 29. Consequently, the area ratio to pressure operating on the differential piston 13 vertically becomes almost 1:1 and both pressures Pi and Po are balanced on the basis of the area ratio. Therefore, pressure reducing operation is stopped and the pressure Po in an outflow passage 15 rises as the pressure Pi in the inflow passage 14 rises.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure reducing valve, and more specifically to a valve that reduces outlet pressure at a predetermined ratio to inlet pressure. This invention relates to a pressure reducing valve that is effective when incorporated into a vehicle.

Trailer towing trucks are sometimes equipped with an anti-jackknife device that prevents the relative bending phenomenon (jackknife phenomenon) between the truck and trailer during braking.
For example, a friction brake device using a cylinder mechanism is built into the connection between the truck and the trailer, and the cylinder mechanism is configured to operate using the pilot pressure output from the brake valve in the truck, so that the connection is activated during braking. It is conceivable that the bending motion is prevented by restraint.

However, in such an anti-jackknife device, the output of the brake valve is directly used as the pilot pressure, so during normal gentle braking, the restraint force on the connecting part pressure becomes excessive and the flexibility of the connecting part becomes A shortcoming was discovered in that it was damaged.

For this reason, it has been considered to operate the cylinder mechanism by reducing the pressure of the brake pulp output at a fixed ratio. However, there is a risk that the restraining force will be insufficient during sudden braking, which requires a true pressure anti-jackknife function, and the trailer and truck may bend.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to reduce the pressure on the outlet side at a predetermined ratio to the pressure on the inlet side, and to
It is an object of the present invention to provide a pressure reducing valve capable of increasing the outlet side pressure to be equal to the inlet side pressure by canceling the pressure reducing action when the inlet side pressure reaches a set value or more.

Hereinafter, the present invention will be described with reference to embodiments shown in the drawings.

FIG. 1 is a vertical cross-sectional view showing a pressure reducing valve according to an embodiment of the present invention, a second view, (B) is a schematic cross-sectional view showing its operation, and FIG. 3 is a characteristic diagram.

In this embodiment, the pressure reducing valve 10 includes a main body 11, and inside the main body 11, a differential cylinder chamber 12 is formed in a cylindrical hollow shape with different diameters. The formed differential piston 13 is fitted so as to be slidable in the vertical direction. In the upper part of the main body 11, an inflow passage 14 is provided for the differential piston 1 in the differential cylinder chamber 12.
It is bored so as to face the large-diameter lower surface space corresponding to the smaller effective area of No. 3. This inflow path 14 is connected, for example, to an output port of a brake valve. An outflow passage 15 is formed on the ceiling wall of the main body 11 to connect the differential piston 1 in the differential cylinder chamber 12.
The trap is drilled so as to face the upper surface space of the large diameter part corresponding to the large effective area of No. 3. This outflow path 15 is connected to the primary side of a pressure converter or the like that converts air pressure into hydraulic pressure in an anti-jackknife device, for example. An exhaust passage 16 is vertically bored approximately in the center of the ceiling wall of the main body 11, and one end of the exhaust passage 16 is opened to the atmosphere via a filter 17. The other end of the exhaust passage 16 projects downward from the ceiling surface of the differential cylinder chamber 12, and an annular exhaust valve seat 18 is formed at the projecting end.

A valve chamber 19 is formed in the center of the upper part of the differential piston 13, and the valve chamber 19 has a passage 20 formed on its side surface and is opened at its ceiling surface, thereby forming an inflow path of the working cylinder chamber 12. 14 and the outflow path 15 substantially constitute a passage. At the top of the valve chamber 19,
Pulp plate 2 with air supply port 21 formed in the center
2 is fitted and fixed by a retaining ring 23.

An air supply valve seat 2 is provided at the periphery of the air supply port 21 of the valve plate 22.
4 protrudes concentrically with the exhaust valve seat 18.

A supply/exhaust valve 25 is built into the valve seat 19 with a compression spring 26 interposed between it and the bottom surface of the valve chamber, and the differential piston 13 of the supply/exhaust valve 25 is located at the upper limit. At this time, the exhaust valve seat 18 is seated and the intake valve seat 24 is unseated.

A back pressure chamber 21 is formed in a small diameter lower surface space corresponding to the back surface of the spool portion of the differential histone 13 in the differential cylinder chamber 12 . In the lower part inside the differential piston 13, a back pressure introduction cylinder chamber (hereinafter referred to as an introduction cylinder chamber) 2B is opened to the valve chamber 19 at the upper end surface 7t,
The side surface is formed to communicate with the back pressure chamber 21 via a passage 29, and therefore, this chamber 28 substantially constitutes a back pressure introduction passage that communicates the inflow passage 14 and the back pressure chamber 27. It turns out. An introduction piston 30 is fitted into the introduction cylinder chamber 28 so as to be slidable in the vertical direction.
A spring fitting chamber 32 is formed in the space behind the piston 30 in the cylinder chamber 28 and is fitted with a compression spring 31 that urges the piston 30 upward. A guide portion 33 protruding from the lower end of the differential piston 13 is slidably inserted into a guide hole 34 formed in the bottom wall of the differential cylinder chamber 12, and the guide portion 33 is slidably inserted into a guide hole 34 formed in the bottom wall of the differential cylinder chamber 12.
is communicated with the atmosphere through an air vent hole 35 formed in the guide portion 33.

A back pressure introduction valve seat 36 is provided in the middle part of the introduction cylinder chamber 28 in an annular shape and protrudes downward, and a back pressure introduction valve 31 is provided at a position opposite to this on the introduction piston 30 so as to be seated and separated. It is being This valve 3T normally has a compression spring 31
The valve seat 36 is pushed up against the introduction piston (capital).
The piston 30 is seated on the piston 30 in response to the pressure in the inflow passage 14, and is disengaged when the push-down blade that acts on the piston 30 reaches the pushing force of the compression spring 31 or higher. A bypass passage 38 is formed in the upper part of the introduction piston 30 so as to bypass the introduction valve 37 and communicate the valve chamber 19 and the back pressure chamber 28.
A check valve 39 formed in a substantially cylindrical shape and made of an elastic material such as rubber is fitted onto the opening of the detour path 38 on the valve chamber 19 side, so that the back pressure chamber 28 is connected to the valve chamber. It is provided to allow flow only in the direction of 19.

Next, the effect will be explained.

1 Pol pressure reduction operation In the state shown in FIG. 1, the pressure in the inflow passage 14 is equal to
The difference lυ1 is sent out from the outflow passage 15 via the upper part of the cylinder chamber 12.

When the pressure in the outflow path 15 reaches a pressure corresponding to the area ratio between the upper surface and the lower surface in the large diameter portion of the differential piston 130 as the pressure in the inflow path 14 increases, the air supply valve seat 24 integrated with the differential piston 13 and the supply/exhaust valve 25 contact each other, and the air supply port 21 is closed, resulting in a balanced state as shown in FIG. The pressure is increased at a predetermined pressure reduction ratio.For example, in a characteristic curve as shown in FIG.

When the pressure in the inflow passage 14 is lowered, the pressure of the supply and exhaust valve 25 is released and attached to the exhaust valve seat 18 in a balanced state due to the force acting on the differential piston 13 according to the area ratio, as in the case of increasing the pressure. As a result, the pressure in the outflow channel 15 is reduced to the pressure in the inflow channel 14.
The pressure is reduced at a predetermined pressure reduction ratio. Therefore, in the POL depressurization straight line portion 11 of the characteristic broken line in FIG. 3, the pressure increase and pressure decrease exhibit characteristics in substantially opposite directions.

■ When a pressure higher than the appropriately set value set by the pressure reduction release operation release compression spring 31 is supplied to the inflow path 14 of the pressure reduction valve 10,
As shown in FIG. 2, the introduction piston 30 is pushed down against the compression spring 31, and the back pressure introduction valve 37 is separated from the back pressure introduction valve seat 36. However, the valve chamber 19, the valve seat 36, the introduction cylinder chamber 28,
Back pressure chamber 27 on the back side of differential piston 13 via passage 29
be guided by. As a result, the area ratio to the pressure acting in the vertical direction on the differential piston 13 becomes approximately 1:1, and based on this area ratio, the flesh pressures PI and Pa create a balanced relationship.

Therefore, after the pressure IJi in the inflow path 14 reaches the set value Pid or more defined by the compression spring 31 pushing up the introduction piston 30, the decompression release portion 1, on the broken line shown in FIG. As shown, outflow channel 1
The pressure Po of 5 maintains a value substantially equal to the pressure Pi of the inflow path 14 and increases by 11 as the pressure of Pi increases. In other words, the pressure reduction operation has been canceled. This results in
For example, in an anti-jackknife device, sufficient pressure is supplied during sudden braking, so the desired anti-jackknife is ensured.

After the pressure reduction operation is released, the pressure on the inflow path 14 side is reduced, and when the pressure Pi becomes less than the set value pid, the introduction piston 30 is pushed up by the compression spring 31, and the back pressure introduction valve 3
7 is seated on the valve seat 36. Furthermore, as the pressure P1 in the inflow path 14 is lowered, the residual pressure in the back pressure chamber 2T is also gradually lowered. That is, when the pressure Pi of the inflow path 14 decreases, the residual pressure in the back pressure chamber 27 becomes higher, so the check valve 3
9 opens, and the residual pressure escapes to the valve chamber 19 through the passage 38.

Even after the introduction valve 37 is seated on the valve seat 36, the back pressure chamber 27 is maintained at a pressure equal to the pressure Pi of the inflow chamber 14, so the pressure Po of the outflow path 15 and the pressure P1 of the inflow path 14 are as follows.
The voltage is lowered while maintaining the l:1 relationship.

Therefore, in σ) pressure reduction after the decompression operation is released, the third
In the broken line shown in the figure, as shown by the pressure decreasing part 13 after the depressurization operation is released, the pressure PO in the outflow path 15 maintains a value approximately equal to the pressure Pi in the inflow path 14, and the pressure decreases according to the decrease in pressure Pi. I'm going to be done.

According to this embodiment, the pressure on the outlet side can be reduced at a predetermined ratio to the pressure on the inlet side, and therefore, when incorporated into an anti-jackknife device, excessive restraint force can be avoided during gentle braking. This can be prevented and appropriate flexibility can be ensured at the connection between the truck and trailer.

In addition, when the inlet side pressure reaches a set value or higher, the depressurization operation for the output side pressure can be canceled.
When incorporated into an anti-jackknife device,
At the time of sudden braking, sufficient restraining force can be ensured at the connection between the truck and the trailer, and bending phenomena between the truck and the trailer can be reliably prevented.

Note that the present invention is not limited to the above embodiments,
Various changes can be made without departing from the gist! E.I.
It goes without saying that it is J-Noh.

For example, the back pressure introduction path that communicates the back pressure chamber and the inflow path and the introduction valve that opens and closes this are not limited to being provided inside the differential piston, but may also be provided within the wall of the differential cylinder chamber. .

By appropriately selecting the effective area of the back pressure chamber with respect to the differential piston, the relationship between the outlet side pressure and the inlet side pressure after release is not limited to 1:1;
As shown in 4, the pressure can be reduced at a ratio different from that of the POL reduced pressure portion It before release.

In the above embodiments, the pressure reducing valve incorporated in the anti-jackknife device was explained, but the application of the pressure reducing valve according to the present invention is not limited thereto.As described above, according to the present invention, the pressure reducing valve according to the present invention It is possible to reduce the side pressure at a predetermined ratio to the inlet side pressure and send it out, and when the inlet side pressure reaches a set value or more, the ratio of the outlet side pressure to the inlet side pressure is different from before. The ratio can be changed arbitrarily.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view showing a pressure reducing valve as an embodiment of the present invention, Fig. 2 (Al, (Bl) is each schematic sectional view for explaining the action, and Fig. 3 is the same <characteristic diagram. 10...Pressure reducing valve, 11...Main body, 12...Differential cylinder chamber, 13...Differential piston, 14...Inflow path, 15...Outflow path, 16... Exhaust path, 17... Filter, 1800. Exhaust valve seat, 19... Valve chamber, 20...
...Passway, 21...Air supply port, 22...Pulp blade, 23...Retaining ring. 24... Air supply valve seat, 25... Supply and exhaust valve, 26...
Compression t-1', 21...back pressure chamber, 2B...introduction cylinder chamber (back pressure introduction path), 29...passage, 30...
- Piston for introduction, 31... Compression spring, 32... Compression spring fitting chamber, 33°°'' guide part, 34... Guide hole, 35... Nitrogen vent hole. 36... Back Pressure introduction valve seat, 37... Back pressure introduction valve, 38
...Detour. Patent applicant: Miwa Seiki Co., Ltd. Representative: Tatsuya Kajihara

Claims (1)

[Claims] +11 A differential cylinder chamber with an inflow passage on the small effective area side and an outflow passage and an exhaust passage on the large effective area side, and a differential cylinder chamber that is internally installed in this cylinder chamber and reciprocates in response to the pressure of the inflow passage. The movement of the differential piston causes air supply valve seats and exhaust valve seats formed between the differential piston and the inlet and outlet passages, and between the inlet and exhaust passages to be individually or simultaneously A supply/exhaust valve to be attached and separated, a back pressure chamber formed on the back surface of the differential piston in the differential cylinder chamber, a back pressure introduction path communicating the back pressure chamber and the inflow path, and A pressure reducing valve that is interposed in the passenger passageway and is equipped with a back pressure introduction valve that opens the introduction passage when the pressure in the inflow passage reaches a set value or more.