JP3187155B2 - Control valve device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control valve device for holding a load on an actuator via a lock valve mechanism.

[0002]

2. Description of the Related Art A switching valve 1 in a conventional control valve device shown in FIG. 5 is switched by the pressure action of pilot chambers 2 and 3 on both sides thereof. And one actuator port 4
Is connected to the bottom chamber 6 of the cylinder C via the lock valve 5, and the other actuator port 7 is directly connected to the rod chamber 8 of the cylinder C. The lock valve 5 has a switching valve connection port 9 connected to one actuator port 4 and an actuator connection port 10 connected to the bottom chamber 6.

When the poppet 11 of the lock valve 5 is at the position shown in the drawing, communication between the two connection ports 9 and 10 is cut off. At this time, the pressure of the bottom chamber 6 is led to the back pressure chamber 12 of the lock valve 5, so that the lock valve 5 is completely closed. On the other hand, the pressure action on the switching valve connection port 9 side
If the pressure action of the back pressure chamber 12 is overcome, the poppet 11 opens. The back pressure chamber 12 is connected to the tank T via an on-off valve 13.
Is in communication with The pilot chamber 14 of the on-off valve 13
Communicates with the pilot chamber 3 of the switching valve 1. When the on-off valve 13 is closed as shown, the pressure of the bottom side chamber 6 acts on the back pressure chamber 12. However, when the on-off valve 13 is opened by the pressure action of the pilot chamber 14, the back pressure chamber 12 communicates with the tank T via the on-off valve 13, and the pressure therein also becomes the tank pressure.

When the pilot pressure is applied to the pilot chamber 3 to switch the switching valve 1 to the right position in the drawing, the pressure oil from the pump P is directly supplied to the rod side chamber 8 through the actuator port 7. At this time, since the pilot pressure also acts on the pilot chamber 14 of the on-off valve 13, the on-off valve 13 is kept open, and the back pressure chamber 1 of the lock valve 5 is opened.
2 becomes the tank pressure. Therefore, the lock valve 5 is opened by the pressure action of the return oil from the bottom side chamber 6 of the cylinder C,
The return oil is returned from the actuator port 4 to the tank T. As a result, the cylinder C contracts.

On the other hand, when the switching valve 1 is switched to the left position in the drawing by applying a pilot pressure to the pilot chamber 2, pressure oil from the pump P acts on the poppet 11 of the lock valve 5 from the actuator port 4. If the acting force on the poppet 11 overcomes the acting force on the back pressure chamber 12 side, the lock valve 5 opens. Therefore, the discharge oil of the pump P is supplied to the bottom chamber 6 of the cylinder C. The return oil from the rod side chamber 8 at this time is returned to the tank T via the actuator port 7, and the cylinder C is extended.

[0006]

In the conventional apparatus as described above, since the on-off valve 13 is in direct communication with the tank T, when a malfunction occurs in the poppet 11 or the on-off valve 13, the bottom chamber 6 is opened. Since the tank C communicates with the tank T via the lock valve 5 and the on-off valve 13, there is a problem that the cylinder C cannot hold the load. An object of the present invention is to provide a control valve device capable of holding a load on a cylinder even when a malfunction occurs in a lock valve mechanism.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided a valve block having a pair of actuator ports communicating with an actuator, and one of the actuator ports communicating with a pump, and the other actuator port communicating with a tank. And a lock valve mechanism provided on one actuator port side and configured to allow the supply oil to the actuator to flow freely and return oil from the actuator to flow only when an operating force is applied. The control valve device provided is assumed. While assuming such a control valve device,
The control valve device of the present invention includes the above actuator and a lock.
A relay passage for communicating with the valve mechanism is provided, and the lock valve mechanism further includes a poppet that opens and closes the one actuator port side, and a back pressure applied to the poppet to close the valve. A pressure chamber to be maintained, a pilot poppet for connecting the pressure chamber to the relay passage when a pilot pressure is applied, and a spool formed in the spool and connecting the relay passage to the tank passage when the pilot poppet is opened. It is characterized by having a switching unit.

[0008]

According to the present invention, the pressure oil in the pressure chamber is not returned to the tank unless the spool is switched to connect the relay passage to the tank passage.

Therefore, according to the control valve device of the present invention, even if the lock valve mechanism malfunctions, the cylinder can hold the load unless the spool is switched.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of the present invention shown in FIGS. 1 to 4, a valve block a is composed of a first block portion 21 and a second block portion 22.
22 are continuously integrated in the thickness direction of the block a. A spool 23 is slidably provided in the first block portion 21, and both ends of the spool 23 face the pilot chambers 24 and 25.

When the spool 23 is at the neutral position shown in the figure, the pump passages 26 and 27 communicate with the neutral flow passage 28, and the opening on both sides of the supply passage 29 is closed by the spool. The relay passage 30 is also closed by the spool 23, and the communication between the relay passage 30 and the tank passage 31 is also cut off. An actuator port 32 is formed in the first block portion 21, and the actuator port 32 communicates with a connection port 34 via a passage 33. A relief valve 35 is provided at the junction of the passage 33 and the tank passage 31.

An actuator port 36 is also formed in the second block portion 22, and an upstream side of a passage 37 communicating with the actuator port 36 communicates with a connection port 38 formed in the first block portion 21.
A lock valve mechanism v is provided in the passage 37, and a downstream side of the lock valve mechanism v is communicated with a relief port 39 formed in the first block portion 21.
This relief port 39 is provided with the other relief valve 40.

As shown in FIG. 3, the lock valve mechanism v has a main poppet 41 and a pilot poppet 42, and a spring 44 is interposed in a pressure chamber 43 between the poppets 41 and 42. The main poppet 41 maintains the closed position shown in the normal state,
The valve is opened by the action of the pressure guided from the connection port 38 to the passage 37. Further, when a pressure is generated on the actuator port 36 side, the pressure acts on the pressure chamber 43, so that the main poppet 41 is kept closed with the action of the spring 44. In this state, when a pilot pressure acts on the pilot chamber 45, the pilot piston 46 pushes the pilot poppet 42 to open the seat portion 47, and the pressure chamber 4
3 and the return passage 48 are communicated.

The pilot chamber 45 communicates with the pilot chamber 25 with one end of the spool facing. Therefore, when pressure acts on the pilot chamber 25, the spool 23 moves to the left in the drawing, and the relay chamber 30 and the tank passage 31 are in communication with each other via the annular groove 49. The annular groove 49 formed in the spool 23
Corresponds to the switching section of the present invention. Further, since the return passage 48 communicates with the relay passage 30 as shown in FIG. 1, the pressure chamber 43 and the return passage 48 communicate with each other. Therefore, the pressure chamber 43 communicates with the tank passage 31 via the return passage 48 → the relay passage 30 → the annular groove 49,
The pressure in the pressure chamber 43 is maintained at the tank pressure. Therefore, the actuator port 36 acting around the main poppet 41
The side pressure overcomes the pressure action in the pressure chamber 43 and causes the main poppet 41 to open.

Next, the operation of this embodiment will be described. By applying pilot pressure to the pilot chamber 24, the spool 23
Is moved rightward from the neutral position in FIG.
8 is closed, and the supply passage 29 and the connection port 38 communicate with each other. Therefore, the pressure oil from the pump P flows into the passage 37 via the pump passage 27 → the supply passage 29 → the connection port 38. The pressure oil flowing into the passage 37 is supplied to the bottom chamber 50 of the cylinder C from the actuator port 36 while pushing and opening the main poppet 41 of the lock valve mechanism v. When the spool 23 is moved rightward as described above, the connection port 34 and the tank passage 31 communicate with each other. Therefore, the return oil from the rod side chamber 51 of the cylinder C is transferred to the actuator port 32 →
The cylinder C is extended by being returned to the tank T through the passage 33 → the connection port 34 → the tank passage 31.

If the spool 23 is returned from this state to the neutral position shown in the figure, the actuator ports 32 and 36 are closed, and the cylinder C stops at that position. At this time, since the pressure of the bottom chamber 50 of the cylinder C acts on the pressure chamber 43 of the lock valve mechanism v, the main poppet 41 maintains the valve closed state as shown in FIG. When a pilot pressure is applied to the pilot chambers 25 and 45, the spool 23 moves to the left in FIG. 1, and the pilot piston 46 pushes the pilot poppet 42 to open the seat portion 47. When the spool 23 moves to the left as described above, the connection port 34 and the supply passage 29 communicate with each other, and the connection port 38 and the tank passage 3
1 and the relay passage 30 communicates with the tank passage 31 via the annular groove 49.

Accordingly, the discharge oil of the pump P is supplied to the rod side chamber 51 of the cylinder C through the supply passage 29 → the connection port 34 → the passage 29 → the actuator port 32. At this time, since the return passage 48 communicates with the tank passage 31 via the relay passage 30 and the annular groove 49, the inside of the pressure chamber 43 is connected to the tank. Therefore, the actuator port 36 acting around the main poppet 41
The side pressure overcomes the pressure action in the pressure chamber 43 and causes the main poppet 41 to open. When the main poppet 41 is opened, the return oil from the bottom chamber 50 of the cylinder C is returned to the tank T through the actuator port 36 → the lock valve mechanism v → the passage 37 → the connection port 38 → the tank passage 31. The cylinder C contracts.

According to the control valve device described above, the pressure chamber 43 of the lock valve mechanism v does not communicate with the tank T as long as the spool 23 is kept at the neutral position. Therefore, even if a malfunction occurs in the lock valve mechanism v, if the spool 23 is returned to the neutral position, no inconvenience such as movement of the cylinder C occurs.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first block portion and a second block portion of a cylinder block separately.

FIG. 2 is a front view of a cylinder block.

FIG. 3 is an enlarged sectional view of a lock valve mechanism.

FIG. 4 is a circuit diagram.

FIG. 5 is a circuit diagram of a conventional control valve device.

[Sign]

 P pump T tank a valve block 23 spool 30 relay passage 31 tank passage 32 actuator port 36 actuator port v lock valve mechanism 41 main poppet 43 pressure chamber

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F15B 11/00-11/22

Claims (1)

(57) [Claims] 1. A valve block having a pair of actuator ports communicating with an actuator and one of the actuator ports communicating with a pump,
A spool for communicating the other actuator port with the tank, and a spool provided on one actuator port side, allow the supply oil to the actuator to flow freely, and the return oil from the actuator is used only when an operating force is applied. In a control valve device including a lock valve mechanism configured to circulate, the actuator and the lock
The lock valve mechanism is provided with a main poppet for opening and closing the one actuator port side, and a pressure for applying a back pressure to the main poppet to maintain a valve closed state. A pilot poppet for communicating the pressure chamber with the relay passage when a pilot pressure is applied, and a switching unit formed on the spool and communicating the relay passage with the tank passage when the pilot poppet is opened. A control valve device.