JPH07139653A - Combination valve - Google Patents

Abstract

PURPOSE:To provide a combination valve which is provided with three functions of a relief valve, a stop valve and a blowout preventing valve, and can appropriately control the flow rate even in the case of the mixed fluid of the liquid with the gas. CONSTITUTION:In a combination valve, an inlet side variable throttling part 136 provided with an inlet side valve 135 is provided on the inlet 130 side of a flow passage 132 of a valve box 104, and an outlet side variable throttling part 110 provided with a differential pressure actuating valve 118 is provided on the outlet 131 side of a flow passage 132 of the valve box 104. The inlet side valve 135 is energized in the closing direction by a spring SP provided on a push-rod 140, and moved in the opening direction by the rearward movement of the push-rod 140 through an opening adjusting cylindrical body 122. The differential pressure actuating valve 118 is energized in the opening direction by a spring 117 provided on a spring chamber 115 and provided with a spool 200 to be abutted on the inlet side valve 135. A back pressure chamber communicating with the primary side F2 of the valve is provided on the back side of the spool 200, and the spring chamber communicates with the secondary side S2 of the valve through the secondary side passage 146.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite valve used in a hydraulic circuit equipped with an accumulator,
More specifically, the present invention relates to a combined valve having the functions of a stop valve, a relief valve and a jetting prevention valve.

[0002]

2. Description of the Related Art In a hydraulic circuit such as an accumulator, a relief valve for preventing an abnormal pressure rise in the hydraulic circuit,
Although a stop valve for discharging the drain of the pipeline is provided separately, the present inventor has developed a relief stop combined valve that combines both of these valves into one, and the production cost is reduced. We have reduced the number and facilitated the mounting work.

This composite valve is constructed as follows. In a relief valve in which a valve body is pressed into contact with a valve chamber by a spring to close the valve, and the valve body is opened when a pressure exceeding the valve closing force of the spring acts, A relief-stop composite valve characterized by connecting a screw for adjusting pressure and pulling up a spring case (see JP-A-1-176870).

This compound valve is normally closed and opens when the pressure of the fluid on the primary side exceeds a predetermined value, and discharges the fluid to the secondary side. It does not have the function of a valve that closes the valve when it opens and prevents high-pressure gas from being discharged to the secondary side. However, if this compound valve is used when the liquid in the accumulator is stored in the tank during maintenance of the accumulator, the inside of the tank may be damaged due to the high pressure inside the tank because it does not function as a jetting prevention valve. Therefore, it is conceivable to separately provide the combined valve and the ejection preventing valve to solve the above problem.

As shown in FIG. 5, the conventional ejection preventive valve 6 has a differential pressure between the primary side chamber 11 and the secondary side chamber 12 when the liquid W of a prescribed amount or more passes through the variable throttle portion 10. Occurs, and the pressure in the primary side chamber 11 is transmitted to the back pressure chamber 14 through the through hole 13. The pressure of the secondary chamber 11 that has received a pressure loss is transmitted to the spring chamber 15 through the passage 16.

When this differential pressure becomes larger than the spring force of the spring 17 which urges in the direction opposite to the arrow A18, the spool 18 moves in the direction of arrow A18, and the variable throttle portion 10 is moved.
Is closed and the supply of the liquid to the tank 7 is stopped.

In FIG. 5, 19 is a spool 14
With a push pin that adjusts the throttle amount, lock nut 20
It is fixed by.

[0008]

The conventional jet-prevention valve is
When only the liquid flows, the spool 17 moves in the valve closing direction and the valve closes when the flow rate exceeds the specified amount. However, when gas is mixed in the liquid and becomes a mixed fluid, for example, when the bladder B of the accumulator ACC is damaged and the gas in the gas chamber 21 leaks into the liquid chamber 5, the flow rate increases above the specified amount. However, due to the following reason, the spool 18 does not move in the direction of the arrow A18, which makes it difficult to regulate the flow rate.

That is, since the pressure loss of gas is smaller than that of liquid, even if the flow rate exceeds the specified amount, in the case of mixed fluid, the differential pressure between the primary side chamber 11 and the secondary side chamber 12 is only liquid. It is much smaller than the spring force and smaller than the spring force. Therefore, the spool 18 cannot be moved in the valve closing direction.

In view of the above circumstances, an object of the present invention is to obtain a composite valve having three functions of a relief valve, a stop valve, and a jetting prevention valve, and capable of appropriately controlling the flow rate even with a mixed fluid of liquid and gas. .

[0011]

According to the present invention, an inlet side variable throttle portion having an inlet side valve is provided on the inlet side of a flow path of a valve housing,
A composite valve having an outlet side variable throttle portion provided with a differential pressure actuating valve on the outlet side of the flow path of the valve housing; the inlet side valve is biased in a closing direction by a spring provided on a push rod. Along with the push rod, it moves in the opening direction via the opening adjusting member by backward movement of the push rod; the differential pressure actuating valve is biased in the opening direction by a spring provided in a spring chamber, and a spool abutting on the inlet side valve is A back pressure chamber communicating with the primary side of the valve is provided on the back side of the spool; the spring chamber communicates with the secondary side of the valve through a secondary passage. The valve aims to achieve the above-mentioned object.

[0012]

[Operation] When the inlet side valve is adjusted to the open state, the differential pressure actuated valve is opened. In this case, when the fluid flows into the inlet of the flow path of the valve housing, the fluid sequentially passes through the inlet side variable throttle portion and the outlet side variable throttle portion and is discharged from the outlet. When the gas of the mixed fluid passes through the inlet-side variable throttle portion, the pressure loss of the gas is smaller than that of the liquid when the amount of the gas is the same as that of the liquid.

Therefore, the liquid in the flow path receives the pressing force of the gas, the hydraulic pressure increases, and the differential pressure between the primary side and the secondary side in the outlet side variable throttle portion increases, so that the differential pressure actuated valve is It operates in the valve closing direction, closes the outlet side variable throttle part, and fulfills the function of an ejection preventive valve.

When the inlet side valve is pressed against the valve seat with a spring to adjust the valve closed state, when the primary side pressure of the inlet side valve becomes higher than the set pressure, the valve is pushed in the valve opening direction to open and The pressure-operated valve also opens, and the liquid is discharged from the outlet of the combined valve to function as a relief valve / stop valve.

[0015]

Embodiment An embodiment of the present invention will be described with reference to FIG. The accumulator ACC is connected to the hydraulic circuit 2 via a connecting pipe 1. The connecting pipe 1 is connected to an oil drain tank 107 via a compound valve 106.

The composite valve 106 has an inlet 130 and an outlet 13
1 is provided with a flow path 132. A frustoconical inlet-side valve 135 is provided on the inlet 130 side of the flow path 132.
Inlet side variable throttle portion 13 including a valve and a cylindrical valve seat 134
6 is provided, and the differential pressure operating valve 1 is provided on the outlet 131 side.
An outlet side variable throttle unit 110 whose flow rate is controlled by 18 is provided. The volume of the flow path 132 is formed in a range that can hold a liquid volume larger than the liquid flow until the differential pressure actuated valve 118 is closed.

One end of the inlet valve 135 is connected to the stopper portion 138 via the connecting portion 137, and the guide portion 137a of the connecting portion 137 is fitted to the cylinder 141.

Since the guide portion 137a is a cylindrical body and is subjected to water pressure in the direction opposite to the inlet side valve 135, the water pressures to the inlet side valve 135 in the same pressure receiving area as the guide portion 137a are mutually different. Canceled.

At the other end of the inlet valve 135, a ring-shaped fitting groove 135a and a spring locking portion 135b are provided. The tip projection 122a of the opening degree adjusting cylinder 122, which is movably provided, is loosely fitted in the fitting groove 135a. The thickness (width) of the tip projection 122a and the width of the groove of the fitting groove 135a are appropriately determined as needed.

At the rear end 122b of the opening adjusting cylinder 122, a spring locking portion 123b is provided at the front end and a free connecting portion 123a is provided at the rear end, and a spring locking body 123 is movably supported. A spring SP for urging the inlet side valve 135 in the closing direction is stretched between the spring locking portion 125b and the spring locking portion 123b. The flexible connecting portion 123a is the holding portion 140 of the push rod 140.
supported by a. The push rod 140 is screwed to a bolt 108 fixed to the housing 104.

The differential pressure operated valve 118 is the inlet side valve 135.
And the central axes of both valves are located on the same straight line C.

The differential pressure actuated valve 118 includes a spool 200,
It is composed of a spring locking portion / stopper portion 145 and a connecting portion 201 for connecting these. The spool 200 is fitted in the cylinder 141, and the spool 2
00 is in contact with the stopper portion 138 of the inlet valve 135. A back pressure chamber 143 is provided between the stopper portion 138 and the spool 200 of the differential pressure operation valve 118, and the back pressure chamber 143 is provided with the differential pressure operation valve 11 via the primary side through hole 144.
8 to the primary side F2.

In the spring chamber 115, the differential pressure actuated valve 11
A spring 117 for urging the valve 8 toward the inlet valve 135 is provided. This spring chamber 115 is a differential pressure operated valve 1
It communicates with the secondary side S2 through 18 secondary side passages 146.

Next, the operation of this embodiment will be described. When the push rod 140 is rotated in the direction of arrow A140, the spring locking body 123 is moved to the direction of arrow A through the pinching portion 140a.
It moves in the 123 direction and presses the spring SP. Therefore, the inlet-side valve 135 moves in the direction of arrow A135 and comes into contact with the valve seat 134, so that the valve is closed. The spring force that presses the inlet valve 135 is appropriately determined as needed.

When the inlet valve 135 is moved, the stopper portion 138 of the inlet valve 135 causes the spool 200 to move toward the arrow A.
It is moved in the 118 direction to close the valve. in this way,
The inlet side valve 135 and the differential pressure actuated valve 118 are interlocked with each other, and the differential pressure actuated valve 118 is automatically adjusted by adjusting the inlet side valve 135. However, the differential pressure operated valve may not be completely sealed.

The fluid in the hydraulic circuit 2 is the accumulator ACC.
Bladder B is pushed up and the pressure in the gas chamber 21 rises when the pressure in the connecting pipe 1 rises extremely at this time, the primary side F1 of the inlet side valve 135 of the composite valve 106 is changed. It becomes larger than the spring force of the spring SP and presses the inlet side valve 135 in the direction opposite to the arrow A135, and at the same time, the force of the spring 117 presses the variable throttle valve 118 in the direction opposite to the arrow A118.

Therefore, the inlet side variable throttle section 136 and the outlet side variable throttle section 110 are opened, and the state shown in FIG.
The fluid W from the connecting pipe 1 passes through the inlet side variable throttle portion 136 and the outlet side variable throttle portion 110 of the composite valve 106, and the oil drain tank 10
It is discharged to 7. In this embodiment, the inlet valve 135 serves as a relief valve / stop valve.

Next, at the time of maintenance of the accumulator ACC, when the push rod 140 is rotated in the direction opposite to the arrow A140, the spring locking body 123 abuts on the opening adjusting cylinder 122 while the tip of the cylinder 122 is in contact. The protrusion 122a causes the valve 135 to move in the direction opposite to the arrow 135. Then, the inlet valve 135 is opened and the differential pressure actuated valve 118 is also opened, so that the throttle portions 136 and 110 are in the state shown in FIG.

As described above, the differential pressure actuated valve 118 adjusts the throttle amount in conjunction with the inlet side valve 135, and the flow rate of the outlet side variable throttle section 110 is 1 to 1 of the flow rates of the inlet side variable throttle section 136. It is adjusted to be 1.2 times. It is because the throttle amount of the inlet side variable throttle unit 136 is equal to the outlet side variable throttle unit 110.
If smaller than that, the gas is at the inlet side variable throttle unit 1
Even when passing through 36, since the pressure loss of the outlet side variable throttle portion 110 is not so large, the differential pressure operating valve 118 does not move,
In the opposite case, the pressure loss is so large that the differential pressure operating valve 118 immediately operates and closes.

After adjusting the throttle portion as described above, the valve 1
When opening 35, the liquid W in the accumulator ACC becomes
It flows into the inlet 130 of the compound valve 106, and flows from the primary side F1 to the secondary side S1 while the flow rate is adjusted by the inlet side variable throttle portion 136.

The liquid W flowing into the secondary side S1 of the inlet side valve 135 flows from the primary side F2 of the differential pressure operated valve 118 to the secondary side S2 while the flow rate is adjusted by the outlet side variable throttle portion 110,
It is discharged from the outlet 131 into the tank 107. This time,
A part of the liquid W on the primary side F2 of the differential pressure actuated valve 118 passes through the primary side through hole 144 and reaches the back pressure chamber 143 to press the differential pressure actuated valve 118 in the direction of arrow A118.

The liquid W on the secondary side S2 is transferred to the secondary side passage 146.
After reaching the spring chamber 115, the spring engaging portion 145 is pressed in the direction opposite to the arrow A118.

When the accumulator ACC is arranged vertically, that is, when the gas chamber 21 is located above the liquid chamber 5, the bladder B of the accumulator ACC is damaged and the gas G in the gas chamber 21 is replaced by the gas G. When leaking in, the fluid in the liquid chamber 5 is discharged from the inlet / outlet of the accumulator ACC by the expansion force of the gas G due to the specific gravity, and then the gas G
Flows into the flow path 132 by its own expansion force.

That is, when gas is mixed in the fluid discharged from the accumulator ACC, the liquid W is always discharged before the gas G is discharged.

Therefore, a gas having a smaller pressure loss than the liquid starts to flow through the inlet side variable throttle portion 136 of the composite valve 106,
When a prescribed amount or more of fluid flows to the secondary side S1, the fluid is pressed by the fluid and the pressure of the liquid located on the primary side F2 of the outlet side variable throttle unit 110 rapidly rises.

As a result, the flow rate at the throttle portion increases rapidly and the differential pressure between the primary side F2 and the secondary side S2 of the outlet side variable throttle portion 110 increases. This differential pressure is spring 1
Since it is larger than the spring force of 17, the differential pressure actuated valve 118 moves away from the inlet side valve 135 in the direction of arrow A118 to close the outlet side variable throttle portion 110, as shown in FIG.

Therefore, the drainage of the liquid W to the tank 107 is stopped and the gas G is not discharged, so that the inside of the drainage tank 107 does not have an abnormally high pressure.

[0038]

EFFECTS OF THE INVENTION Since the present invention is configured as described above, it has three functions of a relief valve, a stop valve, and a jetting prevention valve, and the mixed fluid exceeds the specified amount and passes through the inlet side variable throttle portion and the outlet. The liquid on the primary side of the side variable throttle portion is pressed by the fluid and the hydraulic pressure rapidly rises, the flow rate of the throttle portion suddenly increases, and the pressure loss also increases. Therefore, since the differential pressure in the throttle portion becomes large, the differential pressure actuating valve moves in the closing direction to close the throttle portion. Therefore, even if gas is mixed with the liquid, there is no fear that the fluid of a specified amount or more is inadvertently ejected.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing another state of FIG.

FIG. 3 is a vertical sectional view showing another embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view showing another state of FIG.

FIG. 5 is a vertical sectional view showing a conventional example.

[Explanation of symbols]

 104 housing 106 composite valve 110 outlet side variable throttle section 115 spring chamber 117 spring 118 differential pressure actuating valve 130 inlet 131 outlet 132 flow path 134 valve seat 135 inlet side valve 136 inlet side variable throttle section 143 back pressure chamber 144 primary side passage Hole 145 Spring locking part 146 Secondary side passage F1 Primary side F2 Primary side S1 Secondary side S2 Secondary side

Claims (7)

[Claims] 1. An inlet side variable throttle portion having functions of a relief valve and a stop valve is provided on an inlet side of a flow path of a valve housing, and a jetting prevention valve function is provided on an outlet side of a flow path of the valve housing. A composite valve having an outlet side variable throttle section. 2. An outlet side variable throttle section provided with an inlet side valve on the inlet side of the flow path of the valve casing, and an outlet side variable throttle section provided with a differential pressure actuated valve on the outlet side of the flow path of the valve casing. The inlet side valve is biased in the closing direction by a spring provided on the push rod and is moved in the opening direction by the backward movement of the push rod via the opening adjustment member; The pressure actuated valve has a spool biased in the opening direction by a spring provided in the spring chamber and abuts against the inlet side valve; a back pressure chamber communicating with the primary side of the valve is provided on the back side of the spool. A compound valve characterized in that the spring chamber communicates with the secondary side of the valve via a secondary passage. 3. The opening adjusting member is an opening adjusting cylinder whose tip is loosely fitted in a fitting groove of the inlet valve and whose rear end is loosely fitted with a spring locking body. The composite valve according to claim 2, wherein 4. The combined valve according to claim 3, wherein the spring locking body is loosely fitted to the grip portion of the push rod. 5. The composite valve according to claim 2, wherein the inlet side valve includes a cylindrical guide portion and a stopper portion that abuts against the differential pressure actuated valve. 6. The composite valve according to claim 2, wherein the push rod is screwed to the valve casing. 7. The composite valve according to claim 2, wherein the flow passage has a liquid volume larger than that of the liquid flow until the differential pressure actuated valve is closed.