JPS6128541Y2 - - Google Patents

Description

[Detailed explanation of the idea] This invention relates to a crossover relief valve.

Conventionally, crossover relief valves have a common passage connected to both main circuits for supplying and discharging pressure to the actuator in the valve body, and a pair of pilot pressure control valves are placed facing each other across this common passage. It has been known. However, in order to obtain good override characteristics with this type of crossover relief valve, it is necessary to set a relatively small difference between the outer diameter of the valve and the diameter of the small diameter head that contacts the valve seat. When the diameter difference is set small in this way, the flow resistance during free flow increases. However, if the difference between the outer diameter of the main valve and the diameter of the small-diameter head that contacts the valve seat is set to be large in order to reduce free flow resistance, there is a problem that good override characteristics cannot be obtained. It was hot.

This invention was made to provide a crossover relief valve that reduces flow resistance during free flow without impairing good override characteristics.

Below, Figure 1 shows an example of this invention.
Let's talk about Figure 2.

FIG. 1 is a sectional view showing one embodiment of the present invention, in which 1 indicates a valve body of a crossover relief valve, and a common passage 4 is formed inside this valve body 1. This common passage 4 includes a pressure control valve 2,
2' are arranged facing each other, and the actuator 5
The high-pressure pressure fluid in the main circuit 6 or 7 is connected to the two main circuits 6, 7 for supplying and discharging pressure fluid to the pressure control valve 2 or 2' through the pressure control valve 2 or 2'. It is something that flows in through.

These pressure control valves 2 and 2' are both pilot type pressure control valves and have the same structure as shown in FIG.
One pressure control valve 2 will be explained with reference to FIGS. 1 and 2, and the other pressure control valve 2'
For the same parts, the same numbers will be used for the same parts, and the description will be omitted.

This pressure control valve 2 generally has a sleeve 8 embedded in the end of the common passage 4 of the valve body 1, and a main valve 9, an auxiliary valve 10, and these valves 9, 10 are pressed into the sleeve 8, respectively. The control valve is a control valve that is sealed with a screw cap member 14 that has springs 11, 12, etc. built-in and a pilot valve 13 provided inside. , a large-diameter inner hole 15b behind the large-diameter inner hole 15b, and a rear inner hole 15c further behind the different-diameter inner hole 15 are integrally formed. A first valve seat 16 for the main valve 9 is provided, and a second valve seat 17 for the auxiliary valve 10 is provided in the rear inner hole 15c. This different diameter inner hole 15
A plurality of through holes 8a formed in the peripheral wall of the sleeve 8 are communicated with the main circuit 6.

Large diameter inner hole 15 of the different diameter inner hole 15 of the sleeve 8
A main valve 9 is slidably fitted into the main valve 9, and the small diameter head 9a of the main valve 9 is pressed against the first valve by the pressing force of a spring 11 stretched between it and the auxiliary valve 10. He is seated on seat 16. This main valve 9 has a first valve seat 1
6 has a main valve inner hole 18 slightly larger in diameter than the first throttle 9b bored in the main valve small diameter head 9a.
The main valve inner hole 18 is communicated with the common passage 4 by.

An auxiliary valve 10 is slidably fitted into the main valve inner hole 18 from behind. The auxiliary valve 10 has a passage 20 that communicates the main valve inner hole 18 with a pilot chamber 19, which will be described later, and the inner hole 14 of the screw cap member 14.
Due to the pressing force of the spring 12 stretched between the spring seat body 21 fitted and fixed to the large diameter head portion 10a of the auxiliary valve 10, the large diameter head portion 10a is pushed into the sleeve 8.
It is seated on the second valve seat 17 of the rear inner hole 15c. A pressure chamber 22 is formed inside the sleeve 8 by the auxiliary valve 10, the main valve 9, and the inner hole 15 of different diameters. It communicates with the main circuit 6 via. Note that the spring 12 that presses the auxiliary valve 10 is
A spring 11 with a slightly stronger spring force than the spring 11 that presses the main valve 9 is used, so that the auxiliary valve 10 normally remains seated on the second valve seat 17 as shown.

Behind the auxiliary valve 10, the large diameter head 10a of the auxiliary valve 10, the aforementioned spring seat body 21, and the different diameter inner hole 15 are arranged.
A pilot chamber 19 is formed by the rear inner hole 15c, and the pilot valve 13 at the rear of the pilot chamber 19 has a spring 24 for pressing the pilot valve 13.
When opened against the
It communicates with the pilot valve chamber 26 via the valve 5, and also communicates with the pressure chamber 22 when the auxiliary valve 10 is opened. The pilot valve chamber 26 is connected to the screw cover material 14.
It communicates with a drain circuit 28 through a plurality of passages 27 formed in the drain circuit 28. In addition, 29 in the figure is a cap screw for adjusting the force of the spring 24 for pressing the pilot valve;
0 is the nut for fixing the cap screw 29, 31 is the cap screw 2
9 is a protective cap nut, and 3 in FIG. 1 is a counterbalance valve.

The operation of this embodiment will be explained below.

Now, in FIG. 1, the counterbalance valve 3 is in the switching position 3a on the right side of FIG. 1, and pressure fluid from a pressure fluid source (not shown) is supplied to the actuator 5 via the main circuit 6. 5 flows out into a tank (not shown) via the main circuit 7, the actuator 5 is driven in the direction of arrow A, and when the drive of the actuator 5 reaches a constant speed, the inertia of the driven member also decreases. So,
The fluid pressure in the main circuit 6 has decreased accordingly, and the fluid pressure in the common passage 4 has also become low.

In order to stop the actuator 5 from such a driving state of the actuator, the counterbalance valve 3 is switched to the neutral position 3b shown in FIG. 1 by switching the directional control valve (not shown) to the neutral position. When it falls, main circuit 6 and main circuit 7
The supply and discharge of pressure fluid to and from the actuator 5 is stopped through this. However, since the inertia force of the driven member that was previously driven by the actuator 5 acts on the actuator 5, the actuator 5
continues to rotate in the direction of arrow A even after the supply and discharge of pressure fluid is stopped, and as a result, the fluid pressure in the main circuit 7 begins to rise rapidly.

The fluid pressure in the main circuit 7 that has started to rise in this way acts on the main valve 9' through the through hole 8a' of the sleeve 8' of the pressure control valve 2', and also acts on the second throttle 23' of the sleeve 8'. It acts more on the pressure chamber 22'. When the fluid pressure acts on the pressure chamber 22, the auxiliary valve 10'
, the pressing force of the fluid pressure acting on the difference in pressure receiving area between the second valve seat 17' and the main valve inner hole 18', and the pressing force of the spring 12' and the pressure of the pilot chamber 19 acting on the pressure receiving area difference. The added value of the pressing force due to fluid pressure (fluid pressure of the common passage 4) acts in opposition. This additional value is determined by the auxiliary valve 1 because the pressing force of the spring 12' and the fluid pressure of the common passage 4 are low pressures.
0' is removed from the second valve seat 17' almost at the same time when the fluid pressure of the main circuit 7 is applied. Therefore, the fluid pressure in the pressure chamber 22' becomes the same as the fluid pressure in the pilot chamber 19', and thereafter the pressure fluid in the main circuit 7 continues to flow in through the second valve seat 23, but the flow rate is the same as that in the pilot chamber 19'.
Since it is throttled by the throttle 23, the fluid pressure within the pilot chamber 19 hardly increases. On the other hand, the main valve 9' is
It is unseated from the first valve seat 16' due to the pressing force due to the fluid pressure acting on the pressure receiving area difference between the first valve seat 16' and the large diameter inner hole 15b' (outer diameter of the main valve 9'), and Therefore, the pressure fluid in the main circuit 7 freely flows into the common passage 4.

In this way, when the pressure control valve 2' is free-flowing, the pressure in the pressure chamber 22' decreases as the auxiliary valve 10' moves, so that the main valve 9' changes its outer diameter and the diameter of the first valve seat 16'. Since the valve opens in response to the opening force corresponding to the difference in pressure receiving area based on the difference between the valve and the valve, the flow resistance during free flow is small.

When the pressure fluid that has freely flowed through the pressure control valve 2' as described above acts on the main valve 9 of the other pressure control valve 2 through the common passage 4, it passes through the first throttle 9b of the main valve 9 and passes through the common passage 4. a main valve inner hole 18 communicating with the
and the pilot chamber 19 communicating with the inner hole 18 through the passage 20 of the auxiliary valve 10 are both equal to the fluid pressure of the main circuit 7 and increase in pressure together with the main circuit 7.
During this pressure increase, the pressure receiving area of the main valve inner hole 18 is slightly larger than the pressure receiving area of the small diameter head 9a, and is also larger than the pressure receiving area of the auxiliary valve 10 which receives the fluid pressure of the main valve inner hole 18. Since the pressure receiving area of the large diameter head 10a of the auxiliary valve 10 that receives the fluid pressure of the pilot chamber 19 is larger, the main valve 9 and the auxiliary valve 1
0 does not operate. As the pressure in the main circuit 7 increases, the fluid pressure in the common passage 4, the main valve inner hole 18, and the pilot chamber 19 further increases, and when this fluid pressure overcomes the resistance of the spring 24 for pressing the pilot valve 13, the pilot valve 13 opens and the main valve inner hole 1
8 and the pilot chamber 19 are discharged to the drain circuit 28, the pressure fluid in the common passage 4 flows out to the drain circuit 28 via the first valve seat 9b of the main valve 9, the pilot chamber 19, and the pilot valve 13. do. At this time, the main valve 9 is pushed out from the first valve seat 16 by the pressing force due to the fluid pressure difference generated before and after the first throttle 9b. (At this time, pressure chamber 2
The fluid in pressure chamber 22, which is discharged through throttle 23, has an extremely small volume, so that there is almost no resistance to the operation of main valve 9. ) Also, main valve 9
Since the difference in pressure receiving area between the main valve inner hole 18 and the small diameter head 9a is made small, the main valve 9 responds quickly to the operation of the pilot valve 13.

In this way, when the pressure fluid in the main circuit 7 flows out to the main circuit 6 and the fluid pressure in the main circuit 7 decreases, the pressure in the main valve inner hole 18 and the pilot chamber 19 also decreases.
Pilot valve 13 is closed. Then, both the pilot chamber 19 and the main valve inner hole 18 are pressurized, and the main valve 9 is closed. In this way, the pressure control valve 2 performs a relief operation and maintains the fluid pressure in the main circuit 7 and the common passage 4 at a constant pressure value. Since the diameter of the main valve inner hole 18 that receives the force in the direction of pressing is only slightly larger than the diameter of the first valve seat 16, and the difference in pressure receiving area is small, the fluid pressure in the main valve inner hole 18 begins to drop slightly. Since the main valve 9 is pushed open against the spring 11 by the fluid pressure in the common passage 4, the override characteristic is good.

As mentioned above, when the pressure control valves 2 and 2' operate and the fluid pressure in the main circuit 7 flows out to the main circuit 6, and the fluid pressure in the main circuit 7 is maintained at a predetermined value, The braking force applied to the actuator 5 acts on the actuator 5, and thereby the actuator 5 and the driven member are braked and finally come to a stop.

Next, when the main circuits 6 and 7 are brought into contact with a pressure fluid source and a tank and the actuator 5 is started in the direction of arrow A, the driven member is driven from a stopped state, so the fluid pressure in the main circuit 6 is reduced from the pressure fluid source. However, the fluid pressure in the main circuit 6 acts on the pressure chamber 22 of the pressure control valve 2 and moves the auxiliary valve 10 off the second valve seat 17, causing the main valve 9 to rise to the second valve seat 17. 1 Remove from the valve seat. Therefore, the fluid pressure in the main circuit 6 acts on the pressure control valve 2' via the common passage 4 and is controlled to the control value of this pressure control valve. Further, when the main circuits 7, 6 are connected to a pressure fluid source and a tank, the pressure control valves 2, 2' are operated in the same manner as when the actuator 5 is stopped.

As can be understood from the above explanation, according to the crossover relief valve of this invention, when performing a relief action, the pressure receiving area of the main valve inner hole 18 that receives a force in a direction that prevents the main valve from opening is 1 valve seat 16
Since it is only slightly larger than the opening area of
If the override characteristics are good and there is free flow, the opening of the auxiliary valve causes the main valve to open in response to the large difference in pressure receiving area based on the difference between its outer diameter and the diameter of the first valve seat. Since the valve opens in response to valve force, it has the effect of reducing flow resistance during free flow.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of this invention, and FIG. 2 is an enlarged sectional view of a pressure control valve in the same embodiment. 1... Valve body, 2, 2'... Pressure control valve, 4...
...Common passage, 5...Actuator, 6,7...
...Main circuit, 8...Sleeve, 9...Main valve, 9a...
...Small diameter head, 10...Auxiliary valve, 10a...Large diameter head, 13...Pilot valve, 15...Different diameter inner hole,
15a...Small diameter inner hole, 15b...Large diameter inner hole, 15
c... Rear inner hole, 16... First valve seat, 17... Second valve seat, 18... Main valve inner hole, 19... Pilot chamber, 20... Passage, 22... Pressure chamber, 23... ...Second aperture.

Claims (1)

[Scope of utility model registration request] In the crossover relief valve, a pair of pressure control valves are provided facing each other across the common passage in a valve body having a common passage to which both main circuits for supplying and discharging pressure to the actuator are connected. The valve includes a different diameter inner hole that has a small diameter inner hole that communicates with the common passage and a large diameter inner hole that is connected to the back and is connected to one of the main circuits, and a large diameter inner hole of the different diameter inner hole. A main valve whose small diameter head is seated on a first valve seat that is slidably fitted and formed at a connecting portion between the small diameter inner hole and the large diameter inner hole, and a first throttle formed in the small diameter head. an auxiliary valve that is slidably fitted into a main valve inner hole that communicates with the common circuit and has a large diameter head seated on a second valve seat formed behind the large diameter inner hole of the different diameter inner hole; A pilot chamber behind the auxiliary valve communicates with the main valve inner hole through a passage bored in the auxiliary valve and is controlled by a pilot valve behind the auxiliary valve, and a pilot chamber between the main valve, the auxiliary valve, and a different diameter inner hole. and a pressure chamber formed in this way and connected to one of the main circuits via a second throttle.