JPS6128540Y2 - - Google Patents

Description

[Detailed explanation of the idea] This invention relates to a pressure control valve.

Conventionally, a crossover relief valve has a body with an inner hole to which two main circuits for supplying and discharging pressure fluid to the actuator are connected, and a pair of pilot-type pressure control valves are provided in the body inner hole facing each other. It has been known. However, in this type of crossover relief valve, in order to obtain good override characteristics, the difference between the outer diameter of the main valve of the pressure control valve and the diameter of the small diameter head that contacts the valve seat must be set small. However, when the difference in diameter 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 its valve seat is set to be large in order to reduce free flow resistance, there is a problem in that good override characteristics cannot be obtained.

This invention provides a pressure control valve with reduced free flow resistance without sacrificing good override characteristics.

Hereinafter, FIG. 1, which shows a sectional view of an embodiment of a crossover relief valve using a pressure control valve according to this invention, will be described.

Reference numeral 1 denotes a body, and a body inner hole 2 is formed inside the body 1 to penetrate therethrough. This body inner hole 2 is provided with pressure control valves 6, 6' arranged facing each other, and two main circuits 4, 5 for supplying and discharging pressure fluid to the actuator 3 are connected to the pressure control valves 6, 6'. Connect via.

Since these pressure control valves 6 and 6' have the same configuration, only one pressure control valve 6 will be explained.
Regarding the other part, the same parts are simply indicated by the same numbers with dashes, and the explanation thereof will be omitted. In this pressure control valve 6, a fixed sleeve 7 is fitted and fixed into the body inner hole 2, and the sleeve inner hole 8 of the fixed sleeve 7 is connected to the sleeve through a first hole 9 and a second hole 10 formed in the sleeve peripheral wall. and communicates with one main circuit 4.

11 is a movable sleeve that is slidably fitted into the tip of the sleeve inner hole 8;
1 has a valve seat part 12 formed at its fitting end (rear end), and a locking part 1 on the outer periphery of the other end (tip part).
3 is formed. A spring 14 is tensioned between the locking portion 13 of this movable sleeve 11 and the locking portion 13' of the movable sleeve 11' of the other pressure control valve 6'. As a result, the locking portion 13 of the movable sleeve 11 is press-fitted to the open end of the fixed sleeve 7. This movable sleeve 1
1 closes the first hole 9 in the locked state, but opens the first hole 9 when it slides forward (to the left in the figure) against the spring 14.

15 is a small diameter inner hole 8 located approximately in the center of the sleeve inner hole 8.
This main valve 15 is slidably fitted into a.
is constantly pressed toward the movable sleeve 11 by a spring 17 tensioned inside the pilot chamber 16 behind it, and its small diameter head 18 is pressed against the movable sleeve 1.
The main valve 15 is seated on the valve seat portion 12 of the main valve 15, and the rear end locking portion 19 of the main valve 15 abuts and locks on the step portion 20 at the rear end of the small diameter inner hole 8a of the sleeve inner hole 8. This main valve 15
An annular chamber 2 is formed around the small-diameter head 18 of the main valve 15, the movable small sleeve 11, and the sleeve inner hole 8.
1 is formed, and this annular chamber 21 is connected to the fixing sleeve 7
It communicates with the main circuit 4 through a second hole 10 .
In addition, the main valve 15 has a portion of the small-diameter head 18 that contacts the valve seat portion 12 that is slightly smaller in diameter than the outer diameter of the portion that is slidably fitted into the small-diameter inner hole 8a.
A throttle 22 is provided, and this throttle 22 communicates between the pilot chamber 16 and the body inner hole 2.

The pilot chamber 16 is formed by the main valve 15, the sleeve inner hole 8, and the spring seat 23 fitted and fixed to the rear end of the sleeve inner hole 8.
Spring 3 stretched inside the pilot valve chamber 26 at the back
When the pilot valve 24 opens against the pressure 5, it communicates with a pilot valve chamber 26 behind it through a throttle hole 25 formed in the spring seat body 23. This pilot valve chamber 26 is formed by screwing into the spring seat 23, an inner hole 28 of a screw cap 27 screwed into the open end of the body inner hole 2, and the inner hole 28 of the screw cap 27 from the outside. Cap screw 30 fixed with nut 29
A plurality of through holes 31 formed in the screw cap member 27 communicate with the tank 34 through an annular discharge chamber 32 and a drain circuit 33.

In the figure, 36 is a cap nut that protects the cap screw 26, and 37 is a counterbalance valve. Further, in the other pressure control valve 6', the annular chamber 21' is connected to the second hole 1.
It has exactly the same configuration as the pressure control valve 6 described above, except that it communicates with the other main circuit 5 via 0'.

The operation of the pressure control valve configured as described above will be explained using an example in which the rotation of the actuator 3 in the direction of arrow A is stopped.

When the counterbalance valve is switched to the neutral position 37a as shown in FIG. 1 by switching the directional control valve (not shown) to the neutral position in order to stop the actuator 3, the main circuit 5 and the main Although the supply and discharge of pressure fluid to and from the actuator 3 through the circuit 4 is stopped, the driven member (not shown) that had been driven by the actuator 3 until then is stopped.
Since the inertial force acts on the actuator 3, the actuator 3 continues to rotate in the direction of arrow A, and the fluid pressure in the main circuit 4 thereby starts to rise.

The fluid pressure in the main circuit 4 that has started to rise in this way is
It is transmitted through the hole 10 to the annular chamber 21 and acts on both the movable sleeve 11 and the main valve 15. Then, when the pressure difference between the annular chamber 21 and the body inner hole 2 overcomes the resistance of the spring 14 of the movable sleeve 11, the movable sleeve 11 starts moving toward the other pressure control valve 6', and the annular chamber 21 and At the same time that the body inner hole 2 is communicated with, the first hole 9 of the fixing sleeve 7 also begins to open. Therefore, the fluid pressure from the main circuit 4 passes through the body inner hole 2 to the main valve 1 of the other pressure control valve 6'.
5'.

In this way, the fluid pressure from the main circuit 4 acting on the main valve 15' of the other pressure control valve 6' is transferred to the main valve 15' of the other pressure control valve 6'.
The pilot valve 2 is then
4', and when the resistance of the spring 35' of the pilot valve 24' is overcome, the pilot valve 24' begins to open. Thus, when the pilot valve 24' opens, the pressure in the pilot chamber 16' decreases, creating a pressure difference across the main valve 15', and this pressure difference causes the main valve 15' to move against its pressing spring 17'. Since it is opened, the body inner hole 2 communicates with the other main circuit 5 via the annular chamber 21' and the second hole 10'.

By operating both pressure control valves 6,6' as described above, the pressure fluid from the main circuit 4 is
Free flow passes through the first hole 9 and second hole 10 of one pressure control valve 6 to the body inner hole 2, and flows through the second hole 10' of the other pressure control valve 6' to the other main circuit 5.
leaks to. This outflow causes the main circuit 4
When the fluid pressure in the body bore 2 drops, the pilot valves 24, 2 of both pressure control valves 6, 6'
4' closes and the fluid pressure in the pilot chambers 16, 16' increases, so that the main valves 15, 15' return to their original positions.
At this time, the main valve 15' of the other pressure control valve 6' which is performing the relief action is moved by the movable sleeve 11'.
However, since the movable sleeve 11 has been moved and displaced as described above, the main valve 15 of one pressure control valve 6 does not immediately sit on the valve seat 12' of the other pressure control valve 6. The movable sleeve 11 is seated only when the movable sleeve 11 is returned by the spring 14 after the main valve 15' of the main valve 15' is closed and the body inner hole 2 and the other main circuit 5 are cut off. As a result, communication between the main circuit 4 and the body inner hole 2 via the first hole 9 and the second hole 10 is cut off.

As described above, when the pressure control valves 6 and 6' operate and the pressure fluid from the main circuit 4 flows out to the other main circuit 5 to maintain the fluid pressure in the main circuit 4 at a predetermined value, the pressure reaches that pressure value. A corresponding braking force will be applied to the actuator 3, whereby the actuator 3 and the driven member will be braked and finally come to a stop. Next, when the main circuits 5 and 4 are connected to a pressure fluid source and a tank to start the actuator 3 in the direction of arrow A, the driven member is driven from a stopped state, so the fluid in the main circuit 5 is The pressure tries to rise to the discharge fluid pressure of the pressure fluid source, but in the process of increasing the fluid pressure in the main circuit 5, the fluid pressure in the main circuit 5 causes the movable sleeve 11' of the pressure control valve 6' to move against the spring 14. Since the fluid pressure in the main circuit 5 acts on the pressure control valve 6 through the first hole 9 and the second hole 10, it is controlled to the control value of the pressure control valve 6. In addition, the main circuits 4 and 5 are connected to the pressure fluid source and the tank, and the actuator 3 is connected to the arrow A.
When starting in the opposite direction, the fluid pressure in the main circuit 4 tries to rise in the same way as described above, but since the sleeve 11 of the pressure control valve 6 is moved against the spring 14, the first hole 9 , acts on the pressure control valve 6 through the second hole 10, and is controlled to the control value of the pressure control valve 6'.

FIG. 2 is a partial sectional view showing another embodiment of this invention, and according to this embodiment, the sleeve 11
A hole 38 is further bored in the movable sleeve 1.
1 moves against the pressure spring 14, the main circuit 4
and the body inner hole 2 communicate through the second hole 10 and the annular chamber 21, and also communicate through the first hole 9 and the hole 38 of the movable sleeve 11, which overlap each other as the movable sleeve 11 moves. It has been done. The other configurations are the same as those of the previous embodiment, so the explanation will be omitted.

As mentioned above, this invention makes the diameter of the part where the small diameter head comes into contact with the valve seat slightly smaller than the outer diameter of the part that slidably fits into the small diameter inner hole of the main valve.
The valve seat portion on which the small-diameter head of the main valve comes into contact is formed into a movable sleeve having a diameter larger than the diameter of the portion forming the pilot chamber of the main valve, and when pressure fluid acts on this movable sleeve, the small-diameter head of the main valve Since the valve seat portion is spaced from the head and the hole for free flow is opened, it has the effect of maintaining good override characteristics and reducing flow resistance during free flow.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of this invention, and FIG. 2 is a partial sectional view of another embodiment of this invention. 1...Body, 2...Body inner hole, 3...
Actuator, 4, 5... Main circuit, 6, 6'...
...Pressure control valve, 7,7'...Fixing sleeve, 8,
8'... Sleeve inner hole, 9, 9'... First hole, 1
0, 10'... Second hole, 11, 11'... Movable sleeve, 12, 12'... Valve seat, 13, 13'...
Locking part, 15, 15'... Main valve, 16, 16'...
Pilot chamber, 18, 18'...Small diameter head, 2
2, 22'... Throttle, 24, 24'... Pilot valve.

Claims (1)

[Scope of utility model registration request] In a pressure fluid circuit having two main circuits for supplying and discharging pressure fluid to an actuator, the two main circuits are fitted and fixed into the connecting body inner holes, and one of the main circuits is connected to the first hole and the second main circuit. A fixed sleeve having a sleeve inner hole that communicates with the fixed sleeve through a hole, and a fluid pressure in the other main circuit that is slidably fitted into the sleeve inner hole of the fixed sleeve and that is applied to the fixed sleeve. A valve seat portion is formed by opening and closing the second hole and the locking portion in contact with the first hole.
a movable sleeve having an end on which the fluid pressure in the one main circuit acts through the hole; and a small diameter head abutting the valve seat of the movable sleeve; A pressure control valve consisting of a main valve acting through a throttle and forming a pilot chamber controlled by a pilot valve.