JPS5830973Y2 - Actuator drive circuit - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an actuator drive circuit that drives a plurality of actuators using a plurality of pressure fluid sources.

Conventionally, this type of technology was shown in Fig.
No. 0156).

The conventional actuator drive circuit shown in FIG. 1 includes a first switching valve 3' to which a first actuator 2' is connected to the discharge side of a first pump 1' and a second pump 4'; The second actuator 5' is connected to the second switching valve 6'.

The first switching valve 5'' has a neutral position 19' and a switching position 21'.
, 23', and the second switching valve 6' is in the neutral position 30',
Switching position 31'.

33' and merging switching positions 32' and 34'.

The first switching valve 3' and the second switching valve 6' are the first switching valve 1
Unload passage 1 connecting the discharge side of ' to tank 17'
1', and is branched from this unloading passage 11', is provided with a check valve 13', bypasses the second switching valve, and connects to the discharge side of the second pump 4'.
・It is equipped with ′.

This actuator drive circuit, as shown in Figure 1,
The first switching valve 3' and the second switching valve 6' are in a neutral position 19',
30', the discharge pressure fluid of the first pump 1' and the second pump 4' is discharged into the tank 17'.

When the first switching valve 3' is operated to either the switching position 21' or 23', the discharge pressure fluid of the first pump 1' is supplied to the second actuator 2', and the fluid of the second actuator 2' is transferred to the tank 17'. to drive the second actuator 2'.

When the first switching valve 6' is operated to the switching position 31' or 33', the unload passage 11' is connected to the tank 17', and the discharge pressure fluid of the second pump 4' is transferred to the second actuator 5'. The fluid for the second actuator is supplied to tank 1.
7'.

Therefore, the discharge pressure fluid of the first pump 1' flows out to the tank 17' via the first switching valve 3', the unload passage 11' and the second switching valve 6'.

Then, the second switching valve 6' is set to the merging switching position 32' or the sea bream'
When the operation is performed, the unload passage 11' is closed, so the discharge pressure fluid of the first pump 1' is transferred to the first switching valve 3',
It flows into the discharge side of the second pump 4' via the unload passage 11' and the merging circuit 7', and is supplied to the second actuator 5'.

Therefore, the second actuator 5' has the first pump 1'.
and the discharge pressure fluid of the second pump 4' are combined and supplied.

In the actuator drive circuit having such a configuration, the second actuator 5' can switch between non-merging operation and merging operation by changing the operating position of the second switching valve 6'.
The first actuator 2' is not capable of merging operation.

Further, when the second actuator 5' is switched from non-merging operation to merging operation, a sudden change in speed occurs.

The present invention combines the discharge pressure fluids of the first pump and the second pump, connects the first switching valve and the second switching valve in parallel to the circuit after this merging, and connects the first switching valve and the second switching valve in parallel. 1. by pressure compensation responsive to the load pressure on the high pressure side of the actuator connected to each of the valves. A technical problem is to control the pressure of the merging fluid of the discharge pressure fluid of the second pump to enable merging operation of both the first switching valve and the actuator connected to the second switching valve.

A technical means for solving this technical problem is provided in a circuit connecting the first pump to the first actuator, which includes a first bypass port to which the first pump is connected, a second bypass port, and a first bypass port to which the first pump is connected. The pump includes a pump port to which the pump is connected via a first check valve, and an actuator port to which the first actuator is connected, and the first and second bypass ports communicate with each other, and the pump port communicates with the actuator port. a neutral position in which the first and second bypass ports are closed and the pump port is in communication with the actuator port; and a first switching position in which the first and second bypass ports are closed and the pump port is in communication with the actuator port. a first switching valve having two switching positions; disposed in a circuit connecting the second pump to the second actuator;
a third bypass port connected to the second bypass port; a fourth bypass port connected to the tank; a pump port connected to the second pump; and an actuator port connected to the second actuator; a second switching valve having a neutral position in which the four bypass ports are communicated and the pump port and the actuator port are closed; and a switching position in which the third and fourth bypass ports are closed and the pump port is communicated with the actuator port; a confluence circuit connecting the second pump between the pump port of the first switching valve and the check valve; A pilot section is connected to each actuator port of the second switching valve via a second check valve, and the pressure in the merging circuit is controlled to a value higher than the pressure acting on the pilot section by a certain value. It consists of a pressure compensating valve installed between the merging circuit and the tank.

FIG. 2, which shows one embodiment of this invention, will be described below.

The actuator drive circuit shown in the figure includes a first pump 1 and a second pump 4, a first switching valve 3 disposed between the first actuator 2 and the first pump 1, and a second actuator 5.
and a second pump 4, and a merging circuit 7 that connects the discharge side of the second pump 4 and the discharge side of the first pump 1.

A first switching valve 3//'i is disposed in a circuit connecting the first pump 1 to the first actuator 2, a first bypass port 10 is connected to the first pump 1, and a second bypass port 10 is connected to the pipeline 11. Bypass port 12, first pump 1 is first check valve 13
and the pump port 14 to which the second pump 4 is connected via the merging circuit 7, the first actuator 2
It has two actuator ports 15, 16 to which it connects, a tank port 18 to which a tank 17 connects, and connects the first bypass port 10 and pump port 14 to the second bypass port 12, closes the actuator port 15, and connects the actuator a neutral position 19 (position shown) connecting port 16 to tank port 18;
Connect the bypass port 10 to the second pihame port +12, and also connect the pump port 14 and the actuator port 15.
, the first switching position 20a1 on the right connecting the tank board 18 and the actuator port 16, respectively. In addition to connecting the second bypass ports 14 and 12, the pump port 14, the actuator port 16, and the tank port 18
The left first switching position 20b1 connects the first bypass port 10 and the second bypass port 12, and connects the pump port 14, the actuator port 15, and the tank port 18.
The right second switching position 21a1 connects to the actuator □, g-) 16, respectively. 2nd bypass port 10
and 12 and ", and a left switching position 21b which connects the pump port 14 and the actuator port 15, and the tank port 18 and the actuator port 15, respectively. Runao,
22a and 22b are throttles formed between the pump port 14 and the actuator port 15, 16, which change depending on the operating amount of the first switching valve.

- The second switching valve 6 disposed in the circuit connecting the second pump 4 to the second actuator 5 is connected to the third switching valve 6 connected to the first switching valve '3O second valve 1 passport 12 via the conduit 11.
It has a bypass port 24, a fourth bypass port 26 connected to the tank 17□, two actuator ports 27, 28 connected to the second actuator 5, a tank port 29 connected to the tank 17, and a third bypass port 24. A neutral position 30 (position shown) connects the fourth bypass port 25, closes the actuator port 2γ and the pump port 26, and connects the actuator port 28 to the tank port 29, and the third bypass port 24 and the fourth bypass port. 25 is closed □, and the pump port 2'6 and the actuator port 27 are connected, and the tank port 29 and the actuator port 28 are connected, respectively, and the operation amount of the second switching valve 6 is connected between the pump port 26 and the actuator port 27. a first switching position 31a on the right having an aperture 33a corresponding to the diaphragm 33a; The fourth bypass ports 24 and 25 are closed, and the pump port 26 and actuator port 28 are connected, and the tank port 29 and actuator port 27 are connected, respectively.
The first switching position 31b on the left side, which has a throttle 33b depending on the operation amount of the second switching valve 6 between the actuator port 28 and the first switching position 31a on the right side, is in the same connection state, The diaphragm 3 is in the same connection state as the second switching position 32a on the right without the diaphragm 33a and the first switching position 31b on the left.
3b and a second switching position 32b on the left.

The merging circuit I connects the port 14 of the first switching valve 3 and the check valve 13.
This is a conduit that connects the second pump 4 between the two pumps.

The pressure compensation valve 8 has an inlet 8a connected to the discharge sides of the first pump 1 and the second pump 4, and an outlet 8b connected to the tank 17.
1. A pilot port 40 on which the discharge fluid pressures of the first pump 1 and the second pump 4 act.

and a pilot portion 39 provided at a position opposite to the fluid pressure acting on the pilot port 40 and having a spring.

This pilot section 39 has check valves 35a, 35b,
Connect via 36a and 36b.

These check valves 3"5a, 35b, 36a, 36b are operated by pressure (load pressure) corresponding to the load acting on each of the actuator ports 15, 16, 27. ) has a high pressure selection effect that applies the highest load pressure to the pilot section 39.

Therefore, the pilot port 40 and the pilot part 39 of the pressure compensating valve 8 have the first switching valve 3 and the second switching valve 6, respectively.
The fluid pressure on the upstream and downstream sides when operating the
1st. It has a function of compensating the discharge fluid pressure of the second pumps 1 and 4 to a fluid pressure higher than the highest load pressure on the downstream side by the fluid pressure corresponding to the pressing force of the spring of the pilot part 39.

Note that both the first and second actuators 2 and 5 are configured to operate in both forward and reverse directions.

The actuator drive circuit configured in this way is
As shown in the figure, when the first and second switching valves 3 and 6 are in the neutral positions 19 and 30, respectively, the discharge pressure fluids of the first and second pumps 1 and 4 merge in the first switching valve '3, Pipe line 11, third and fourth bypass ports 1-24, 25 of second switching valve 6
It flows out into tank 17 through.

When the first switching valve 3 is switched from the illustrated neutral state to the first switching position 20a on the right, the discharge pressure fluid of the first pump 1 is transferred to the first switching position 20a of the first switching valve 3. 2nd bypass port 10,1
2, the pipe line 11, and the 3rd one of the second switching valve 6. It flows out into the tank 17 through the fourth bypass port 24, 25.

That is, the first pump 1 has existed until the unloading period.

The discharge pressure fluid of the second pump 4 flows into the first actuator 2 through the confluence circuit 7, the pump port 14 of the first switching valve 3, and the actuator port 15.

The fluid flowing out from the actuator 2 passes through the actuator port 16 and the tank port 18 of the first switching valve 3 and flows out into the tank 17 .

In this way, the first actuator 2 is actuated in one direction by the discharge pressure fluid of the second pump 4.

At this time, the pressure compensation valve 8 is operated on the upstream side of the first switching valve 3, that is, the fluid pressure of the merging circuit 7 and the load pressure of the first actuator 2 are acting oppositely, and the discharge fluid pressure of the second pump 4 is acting on the pressure compensating valve 8. is held at a pressure greater than the load pressure by a constant value corresponding to the tension of the spring of the pilot part 39, so the first
The actuator 2 has a speed corresponding to the operation amount of the first switching valve 3 regardless of the load.

Next, when the first switching valve 3 is switched to the second switching position 21a on the right, the first switching valve 3 is switched to the second switching position 21a on the right. 2nd bypass port 1
0 and 12, the discharge pressure fluid of the first pump 1 flows into the merging circuit 7 via the check valve 13.

Therefore, the first actuator 2 includes the first and second pumps 1,
4 discharge pressure fluids will be supplied.

In addition, when the first switching valve 3 is operated to the left first switching position 20b1 and the second switching position 21b, the operation is the same as in the above case except that the operation of the first actuator 2 is in the opposite direction. be.

Next, when the first switching valve 3 is set to the neutral position 19, the second
When the switching valve 6 is operated to the right first switching position 31a, the third. Since the fourth bypass ports 1-24 and 25 are closed, the discharge pressure fluid of the first pump 1 merges with the discharge pressure fluid of the second pump 4 via the check valve 13 and the merging circuit 7, and the second
Pump port 26 of switching valve 6, actuator port 2
7 through the second actuator port 27
It flows into the actuator 5.

The fluid flowing out from the second actuator 5 flows into the tank 17 via the actuator port 28 and the tank port 29 of the second switching valve 6 .

At this time, the pressure compensating valve 8 has an upstream side of the second switching valve 6 acting on the pilot port 40 and the pilot part 39, and an upstream side of the second switching valve 6 acting on the load pressure of the second actuator 5. The fluid pressure is kept high by a constant value corresponding to the tension of the spring of the pilot part 39. Therefore, the operating speed of the second actuator 5 becomes a value corresponding to the operation amount of the second switching valve 6.

Next, when the second switching valve 6 is operated to the right second switching position 32a, the first switching valve 6 is moved to the right second switching position 32a. The discharge fluid pressure of the second pump flows into the second actuator 5 in the same manner as described above, but at this time, the second
Pump port 26 and actuator port 2 of switching valve 6
7, the speed of the second actuator 5 is the same as that of the first actuator 5 regardless of the operation amount of the second switching valve 6.
．． The value corresponds to the flow rate of the pressure fluid discharged from the second pumps 1 and 4.

Note that when the second switching valve is operated to the left first switching position 31b1 second switching position 32b, the second attituent 5
The operation is the same except that the operation is in the opposite direction to that in the previous case.

The case where the first and second switching valves 3 and 6 are operated separately has been described above, but when they are operated simultaneously, the second switching valve 6 closes the bypass circuit, so the first switching valve 3 and the second switching valve 3 close the bypass circuit.
Regardless of the switching position of the switching valve 6, the combined flow rate of the discharge pressure fluids of the first and second pumps 1 and 4 is supplied to the first and second actuators 2 and 5 in the housing.

At this time, the pilot part 39 of the pressure compensation valve 8 has a first
The highest load pressure among the load pressures of the actuator 2 and the second actuator 5 is the check valve 35 a t 35 b
> 36a > 36b is selected and acts, so
1st. The discharge fluid pressure of the second pump 1.4 is kept at a value higher than the maximum load pressure.

In addition, in the above embodiment, if the second switching valve 6 does not need to accurately control the operating speed of the second actuator 5, the second switching valve 6 may be a switching type in which the right and left first switching positions 31a and 31b are omitted. It can also be used as a valve.

Further, although the first actuator 2 and the second actuator 5 are of a double-acting type, they may be of a single-acting type.

According to this drive circuit, the first pump 1 is unloaded when the first actuator 2 operates under high load and at low speed and the second actuator 5 is at rest.

When the second actuator 5 starts to operate at high speed from this state, the discharge pressure fluids of the first and second pumps 1 and 4 are appropriately merged, resulting in the effect that power can be used efficiently. has.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an example of the configuration of a conventional actuator drive circuit, and FIG. 2 is a circuit diagram showing the configuration of an embodiment of this invention. 1...First pump, 2...First actuator, 3...First switching valve, 4...
Second pump, 5...Second actuator, 6.
...Second switching valve, 7...Merge circuit, 8.
...Pressure compensation valve, 10...First bypass port, 11...Circuit, 12...Second
Bypass port, 14...Pump port, 15
, 16... Anti-1 Eta port, 19...
...neutral position, 20a. 20b...First switching position, 21a, 21b...
...Second switching position, 24...Third bypass port, 25...Fourth bypass port, 26.
... Pump port, 27.28 ... Actuator port, 30 ... Neutral position, 31a
, 31b...first switching position, 32ay32b.
...Second switching position.

Claims (1)

[Claims for Utility Model Registration] The first pump is arranged in a circuit connecting the first actuator, and the first pump is connected to the first bypass port, the second bypass port, and the first bypass port. A pump port connected via a check valve and a first actuator, -
1. 1st and 2nd? <A neutral position in which the pump port is communicated with the pump port and the actuator port 1 is closed;
The first step is to connect the pump hoard to the actuator port.
, one switching position, and a second position that closes the pump port and communicates the pump port with the actuator port.
and a switching position. 1st, 1st switching valve, and: 2nd valve to 2nd actuator (
A third piper port connected to the second bypass port, a fourth piper port connected to the tank, and a pump port connected to the second pump; A second actuator, L-L, is provided with an actuator boat to which the motor is connected, and a neutral position in which the third and fourth bypass ports are communicated and the pump boat steams and the actuator port is closed; a second switching valve having a switching position that closes the passport and communicates the pump port with the actuator port; a confluence connecting the second pump between the pump port of the first switching valve and the check valve; Circuit: Said 1. The merging circuit has a pilot section connected to each actuator port of the second switching valve via a check valve, and the merging circuit controls the pressure of the merging circuit to a value higher than the pressure acting on the pilot section by a certain value. The actuator drive circuit consists of a pressure compensation valve installed between the tank and the tank.