JPH04119205A - Operation controller of multiple actuator with single variable capacity pump - Google Patents

Abstract

PURPOSE:To prevent sudden change in speed of other actuators by providing a signal circuit of maximum load pressure selected by a shuttle valve with a second relief valve of set pressure lower than the relief pressure of an actuator or pressure reduction valve. CONSTITUTION:The maximum load pressure signals of respective actuators such as a backet cylinder and the like selected by shuttle valves 42-47 are led to a flow control valve 57 by means of a signal circuit 65 while a main relief valve 63 is provided at a discharge circuit 61. A second changeover device 70 for changing over the signal pressure of the signal circuit 65 is composed of second changeover valve 72 and second relief valve 73, and the relief pressure of the second relief valve 73 is set lower than those of relief valves 21A, 21B-26A, 26B. With the constitution, even one of the actuators which operate in parallel by proper operation of the second relief valve 73 is stopped, abrupt change in speed of others can be prevented.

Description

Detailed Description of the Invention (Field of Industrial Application) This invention relates to an operation control device for a plurality of actuators using a single variable displacement pump, and in particular a control device for controlling the operation of a plurality of actuators using a single variable displacement pump, and in particular, a control device for controlling the operation of a plurality of actuators using a single variable displacement pump. The present invention relates to an operation control device for a plurality of actuators using a single variable displacement pump, in which the actuators can be activated by a single variable displacement pump.

(Prior art) As an operation control device for multiple actuators using a single variable displacement pump, it is possible to drive multiple actuators installed in conventional industrial machinery such as construction machinery and loading machinery with a single variable displacement pump. For example, JP-A-1-17
There is one as shown in Publication No. 6.803.

This device connects a plurality of actuators (for example, two) in parallel to the discharge circuit of a single variable displacement pump through flow control valves each having a convensator valve, and connects the plurality of actuators selected by a shuttle valve to the discharge circuit of a single variable displacement pump. In a pump control device that controls the discharge amount of the variable displacement pump by comparing the maximum load pressure of Control cylinders are each provided with a piston that is acted upon by the discharge pressure of the variable displacement pump in the opposite direction, and when the force in the opposite direction becomes dominant over the pressing force in the one direction. , the control cylinder is connected to a compensator valve such that a piston rod of the control cylinder deflects the compensator spring.

In this case, the compensator spring pressure of the compensator valve provided around the flow rate control valve is determined in advance by the differential pressure between the selected maximum load pressure of the plurality of actuators and the discharge pressure of the variable displacement pump. By providing a control cylinder that weakens the spring force of the spring when the value falls below a set value, the total flow rate passing through each flow control valve that controls the operation of the plurality of actuators is reduced, and high load The pressure side actuator can be operated continuously without stopping its movement.

(Problem to be Solved by the Invention) However, in this device, the compensator spring of the compensator valve provided in the flow control valve is connected to the selected maximum load pressure of the plurality of actuators and the discharge pressure of the pump. By providing a control cylinder that weakens the spring force of the spring when the differential pressure becomes less than a set value, the total flow rate of each flow control valve that controls the operation of the plurality of actuators is reduced, and one high load While the controllability is improved over the previous model in that the pressure actuator can continue to operate without stopping its movement, on the other hand, when multiple actuators are in operation,
When going from operating only the high pressure actuator to operating it simultaneously with the low pressure actuator, the working speed of the low pressure actuator becomes extremely slow, and when you stop operating the high pressure actuator and shift to operating only the low pressure actuator, the low pressure The oil flow to the actuator side increases rapidly, causing a sudden change in the speed of the low-pressure actuator.
There was a problem in that there was a risk of accidents occurring for operators and others working around the low-pressure actuator.

The present invention has been made by focusing on the problems in the conventional example, and includes an operation control device for a plurality of actuators installed in parallel in a discharge circuit of a single variable displacement pump.
A second circuit is provided in the signal circuit for the selected maximum load pressure to operate at a timely setting pressure lower than the relief pressure of the actuator.
The present invention aims to provide an operation control device for a plurality of actuators using a single variable displacement pump that can solve the above problems by providing a relief valve or a pressure reducing valve directly or via a second switching valve.

(Means for Solving the Problems) In order to solve the problems of the conventional example as described above, the present invention connects a plurality of actuators in parallel to the discharge circuit of a single variable displacement pump via a directional control valve with a compensator valve. and controls the operation of the plurality of actuators by adjusting the discharge capacity of the variable displacement pump by comparing the maximum load pressure of each of the actuators selected by the shuttle valve with the discharge pressure of the variable displacement pump. In the control device, the signal circuit for the selected maximum load pressure is provided with a second relief valve or a pressure reducing valve having a set pressure lower than the relief pressure of the actuator.

(Function) Since the present invention has the above-described configuration, a plurality of actuators connected in parallel to the discharge circuit of a single variable displacement pump can be controlled by switching the directional valves of the pressure oil supply and discharge circuits to each of them. In addition to being able to be operated simultaneously or separately, a second relief valve or pressure reducing valve is provided directly in the signal circuit for controlling the discharge amount of the single variable displacement pump, with or without a second switching valve. The signal pressure of the signal circuit is lowered, and the discharge amount is controlled by comparing the signal pressure with the discharge pressure of the variable displacement pump, thereby preventing sudden changes in the speed of the low-pressure side actuator.

(Example) Hereinafter, an example of the operation control device for multiple actuators using a single variable displacement pump according to the present invention will be described with reference to FIGS. 1 to 3.

(First Embodiment) FIG. 1 is an explanatory diagram of a control circuit according to a first embodiment of the present invention, and FIG. 2 is an explanatory diagram of its characteristic curve.

In FIG. 1.2, reference numerals 6 to 6 indicate a plurality of actuators such as a packet cylinder, a boom cylinder, and a left travel motor driven by a single variable displacement pump 51;
These are the right travel motor, swing motor, and arm cylinder.

Reference numeral 10 denotes a directional control valve block, and 11 to 17 indicate a packet cylinder 1, a boom cylinder 2, a left travel motor 3, a right travel motor 4, which are provided in the direction change valve block 10. Directional switching valves for switching the direction of supply and discharge of pressure oil to the swing motor 5, arm cylinder 6, etc., 11A to 17A are drive circuits for each actuator 7 (actuator 7 is not shown), 21A, 21B, 22A, 22B, 26A,
26B is a relief valve provided in the drive circuits 11A to 16A for supplying and discharging pressure oil to the packet cylinder 1, boom cylinder 2, arm cylinder 6, etc.

31 to 37 are a packet cylinder 1, a boom cylinder 2, a left travel motor 3, a right travel motor 4, a swing motor 5,
Compensator valves 31A to 37A are provided in the connection circuit (pressure oil supply circuit) between the arm cylinder 6 and the discharge circuit 61 of the variable displacement pump 51, which will be described later.
Adjustment cylinders 1 to 37 adjust the conveyor spring pressure, 42 to 47 are maximum load pressures generated in the packet cylinder 1, boom cylinder 2, left travel motor 3, right travel motor 4, swing motor 5, arm cylinder 6, etc. 52 is a tilting plate of the variable displacement pump 51, 53 is a tilting cylinder, 54 is an arm interlocked with the cylinder rond of the tilting cylinder 53, 57 is a flow rate control valve,
58 and 55 form a horsepower control valve. 59 is a remote control valve, 62 is a discharge circuit, 63 is a main relief valve provided in the discharge circuit 61, 65 is a signal circuit, 67 is an unload valve, and T is a tank.

70 is a second circuit for switching the signal pressure (upper limit value) of the signal circuit 65;
A switching device, 71 is a second signal circuit branched from the vicinity of the flow control valve 57 of the signal circuit 65, 72 is a second switching valve provided in the second signal circuit 71, and 73 is provided in series with the second switching valve 72. With the second relief valve.

The relief pressure of this second relief valve is
It is set lower than the relief pressure of 1A to 26B.

Note that the second switching valve 72 and the second relief valve 73 are
The relief pressure of the main relief valve 63, which may be provided in a reverse relationship to the embodiment of FIG. 1, is set higher than that of these relief valves 21A to 26B.

(Operation of the first embodiment) First, pressure oil supplied from the discharge circuit 61 of the variable displacement pump 51 is passed through the compensator valves 31 to 37 and the directional control valves 11 to 17 to the packet cylinder 1. Boom cylinder 2, left travel motor 3, right travel motor 4. Swivel motor 5. It is supplied to actuators such as the arm cylinder 6 and discharged from the discharge circuit 62 to the tank T, thereby driving each of the actuators 6 to 6 in a desired direction.

At that time, the load pressure of each actuator 1 to 6 etc. is transmitted to the shuttle valve 42 by a signal circuit 65 based on the respective load pressure.
The flow control valve 5 selects the highest load pressure by connecting via 47 to 47, and operates based on the differential pressure between the selected highest load pressure and the discharge pressure of the variable displacement pump 51.
7, the tilting angle of the tilting plate 52 of the variable displacement pump 51 is adjusted by supplying and discharging pressure oil to the tilting cylinder 53 (upper tilting cylinder 53 in FIG. 1). Adjust the discharge amount.

In addition, the horsepower control valves 55 and 58 control the horsepower of the variable displacement pump 51 to prevent overload on the engine, and the single variable displacement pump 51 simultaneously controls the operation of multiple actuators, etc. The discharge amount of pressure oil necessary for driving is ensured, and these operations themselves are substantially the same as those of conventional devices of this type.

However, in this first embodiment, the maximum value of the load pressure of the plurality of actuators 41 to 4 is set to
The tilting angle of the tilting plate 52 (therefore, its discharge amount) is adjusted by the flow rate control valve 57 which is operated based on the comparison between the maximum load signal of the signal circuit 65 selected by 8 and the discharge pressure of the variable displacement pump 51. At the same time, the second switching valve 72 of the second signal circuit 71 branched from the signal circuit 65 is switched to 1, for example, before operation of a high-pressure actuator such as the fork grab cylinder 1, and the second relief valve 73 of the second signal circuit is switched.
By setting the relief pressure of the variable displacement pump 51 to a desired value in advance, the discharge amount of the variable displacement pump 51 is controlled, and by stopping the operation of some high pressure actuators (for example, fork grab cylinder 1), other low pressure actuators (for example, , prevents the occurrence of an unexpected sudden speed change (rapid rotation) of the swing motor 5).

This effect will be explained below for each operating state.

(Second switching valve 72 open position W) Relief valves 21A to 26A, 21B to 26B
Set pressure of the second relief valve 73 + Set pressure difference of the unload valve 67 (1) When the fork grab is gripping an object, the fork grab cylinder 1 is in a relief state.

At this time, the discharge pressure of the pump 51 tries to rise to the relief pressure PR1 of the relief valve 21B + the set differential pressure of the flow rate control valve 57. Since the differential pressure is set at the load valve 67, the discharge pressure from the variable displacement pump 51 is
The relief pressure becomes the sum of the pressure difference set between the relief valve 73 and the unload valve 67, and is discharged from the unload valve 67 to the retank T. The set differential pressure of the unload valve 67 is the flow rate control valve 57.
Since the differential pressure is larger than the set differential pressure of the pump 5, the flow control valve 57
1 is maintained at the minimum value (left position).

Therefore, power loss is smaller than in the conventional example. At this time, the oil flow to packet (fork grab) cylinder 1 is approximately 0.
However, the pressure is guaranteed.

(1') If this second switching circuit 71 is not provided, the discharge pressure of the variable displacement pump 51 will be the relief pressure PR of the relief valve 21B + the set differential pressure of the flow rate control valve 57, The flow rate becomes the spool set flow rate, and within the flow rate range set by the horsepower control valve 55.58, the relief pressure PR set by the relief valve 21B,
Relieve with.

(2) In the state of (1) above, when the swing motor 5 is operated to swing, the operating pressure of the swing motor 5 (set pressure PR1 set by the relief valve 21B of the packet cylinder 1), and the unload valve 67 + set pressure of the second relief valve 73 ), the unload valve 67 is closed and the pressure oil discharged from the variable displacement pump 51 flows to the swing motor 5 side via the directional control valve 15 .

At this time, due to the flow rate control action of the compensator valve 35 on the swing motor 5 side, the set flow rate tends to flow to the swing motor 5 (low pressure actuator), so the discharge pressure P of the variable displacement pump 51 tends to decrease. Since the differential pressure is set to be constant due to the action of the flow rate control valve 57, the flow rate required by the swing motor 5 is within the flow rate range set by the horsepower control valves 55 and 58.

The discharge amount of the variable flow rate pump 51 is increased.

Therefore, the amount of pressure oil supplied to the swing motor 5 satisfies the set flow rate of the swing motor 5.

(2') If the second switching valve 72 of the second switching circuit 71 of this first embodiment is not provided, the discharge pressure of the pump 51 will be equal to or equal to the relief pressure PR set by the relief valve 21B of the packet cylinder 1. Within the flow rate range set by the horsepower control valves 55 and 58, the discharge flow rate of the pump 51 becomes the set flow rate for the packet (fork grab) cylinder 1 and the swing motor 5. is the sum of

These relationships can be summarized as follows.

(1) (1') pressure crab
(Set pressure of second relief valve 73 + set differential pressure of unload valve 67) < P Rx flow rate: Pump minimum flow rate (Set flow rate (2) (2') Pressure =
(Setting pressure of second relief valve 73 + setting differential pressure of flow rate control valve 57) <PR1 + setting differential pressure of flow rate control valve 57 Flow rate: swing setting flow rate + fork grab cylinder circuit flow rate (actual flow amount) + swing circuit Flow rate (actual flow rate) In conventional examples, power excavators, etc.
- When fishing on a boat, the sum of the set flow rates of each port of the directional switching valve becomes larger than the maximum value of the discharge flow rate of the variable displacement pump 51.

To summarize the above, according to the first embodiment, the following effects can be expected.

(Comparison between the first embodiment and the conventional example) (A) State PL of grasping the object with the fork grab
(Example) Setting of second relief valve 73 Setting differential pressure pg of indenter unloading valve 67 (Conventional example) Relief pressure PR of relief valve 21B,
If the set differential pressure of the flow control valve 57 is the set differential pressure of the flow control valve 57, the discharge amount of the pump 51 when P□ <P2 Q□ Pi Qz The discharge amount of the pump 51 when P2, > Q.

However, in this state.

Pl　　　P.

= (Setting pressure of the second relief valve 73 + Setting differential pressure of the flow rate control valve 57) Therefore, the flow rate control valve 57 reaches the left position in FIG. 1, and the variable displacement pump 51 maintains the minimum discharge amount Q1. Hold.

Q, (Setting flow rate QF of packet (fork grab) cylinder circuit) Note that this Q is relieved by the unload valve 67.

In the conventional example, Q2 is relieved by relief valve PR1.

Q,　<　Q.

(B) In the state of (A) above, the circuit of the swing motor 5 is opened, and the compensator valve 3 of the same swing motor 5 circuit is opened.
Since the pressure oil flows through the directional control valve 15 and the directional control valve 15,
The discharge pressure of the variable displacement pump 51 decreases to P3, the unload valve 67 is closed, and the variable displacement pump 51 discharges the flow rate necessary to maintain the operating pressure P3.

Further, in this state, no pressure oil flows to the packet (fork grab) cylinder 1 side, and only pressure is maintained.

The discharge amount of the pump 51 at P3 is determined by Q in the control diagram in Fig. 2.
6, then Q, >Qs'=Q.

Packet (fork grab) cylinder circuit flow rate (actual flow rate) Q: 0 Swing motor 5 circuit setting flow rate ” = Qs Swing motor 5 circuit flow rate (actual flow rate) = Q4 The pump 51 discharge amount at this time is 4 Qs, and the set flow rate of the 5 circuits of the swing motor can be sufficiently secured.

Note that the set flow rate Qs of the drive circuit 15A of the swing motor 5 is smaller than the limit value of the discharge amount by the horsepower control valve 58.55.

(Conventional example) Qf = Swing circuit flow rate (actual flow rate) The drive circuit of the swing motor 5 opens and its compensator valve (swivel)
Because pressure oil flows through.

The flow rate of the pump 51 is to be increased to maintain P2, but due to the horsepower control valve 58.55, the flow rate of the pump 51 is increased.
1 can only discharge a flow rate Q2.

QF: Set flow rate of packet (fork grab) cylinder, then Q2 < QS + QF Since there is an anti-saturation mechanism, Q2 = Q
sx%10QFX%. Note that in the above formula, % is the set flow rate reduction rate during anti-saturation operation.

Due to the above, Qs:>QsX%=Q.

Therefore, the swirl circuit flow rate (the actual flow rate) is much smaller than the set flow rate.

The above is a comparison between the embodiment of the present invention and the conventional example. In the present invention as well, if the second switching valve 72 is set to the closed position, the packet (fork grab) cylinder 1
The drive circuit 11A is set to high pressure by relief valves 21A and 21B.

Although the second switching valve 72 is constructed as a solenoid valve in this embodiment, it may be constructed of a type that switches between hydraulic pressure and pneumatic pressure.

(Second Embodiment) Next, a second embodiment of a system for controlling the operation of multiple actuators by a single variable displacement pump according to the present invention, particularly a second switching device thereof, will be described with reference to FIG. do. Note that the same names and symbols are used for parts common to the first embodiment shown in FIGS. 1 and 2.

In FIG. 3, reference numeral 80 denotes a second switching device similar to the second switching device 70 in the first embodiment;
0 is the same as in the first embodiment.

A second electromagnetic switching valve 8 is connected to a second signal circuit 71 that branches from the vicinity of the flow rate control valve 57 (near the position just before the signal circuit 65).
2 and a second relief valve 73, and this second electromagnetic switching valve 82 is automatically operated by an electromagnetic signal based on the operation of any one of the actuators 1 to 6, for example, a packet (fork grab) cylinder. The switching is performed by detecting that the directional switching valve 11 of the arm cylinder 1 is operated and the directional switching valve 15 or 16 of the swing motor 5 or the arm cylinder 6 is operated.

The remaining structure and operation are substantially the same as those of the first embodiment including the second switching device 70.

(Third Embodiment) Next, a third embodiment of the operation control device for multiple actuators using a single variable displacement pump according to the present invention will be described with reference to FIG. 4. Note that the same names and symbols are used for parts common to those of the first embodiment shown in FIGS. 1 and 2.

In this third embodiment, as shown in FIG. 4, an electromagnetic proportional relief valve 92 is provided in a second signal circuit 91 branching from a signal circuit 65 that controls a variable displacement pump 51.

The relief pressure of the electromagnetic proportional relief valve 92 of this third embodiment is controlled by an electric signal so that the set pressure is lower than that of the port relief valve 21B of the drive circuit 11A of the packet (fork grab) cylinder 1. Due to the operation of the proportional relief valve 92, the second switching valve 72 in the first embodiment is in an open state. Almost similarly to the second relief valve 73 of the signal circuit 65, the upper limit value of the signal pressure of the signal circuit 65 is lowered.

In addition, the relief pressure of the electromagnetic proportional relief valve 92 is
The second switching valve in the first embodiment is set higher than the relief pressure of the relief valve 21B of the drive circuit 11A of the high-pressure actuator (packet: fork grab cylinder 1 in this embodiment) of the operation control device for the plurality of actuators. 72 is in the same state as the closed state.

The remaining structure and operation are substantially the same as those of the first embodiment.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIG. Note that the same names and symbols are used for parts common to those in the first embodiment shown in FIGS. 1 and 2.

In this fourth embodiment, a variable pressure reducing valve 101 is provided in the signal circuit 65 itself, and the set pressure of the variable pressure reducing valve 101 of this fourth embodiment is determined by a pressure oil signal to its pilot section. The degree of pressure reduction is controlled.

Then, the set pressure of the pressure reducing valve 101 is adjusted to the set pressure of the pressure reducing valve 101 in the packet (
Fork grab) Cylinder 1 port relief valve 21B
By setting the pressure lower than the set pressure, the same state as when the second switching valve 72 is opened in the first embodiment is achieved. Further, by not reducing the pressure, the situation is the same as when the second switching valve 72 is closed in the first embodiment.

The remaining structure and operation are substantially the same as those of the first embodiment.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described with reference to FIG. 6. Note that the same names and symbols are used for parts common to the fourth embodiment shown in FIG.

In this fifth embodiment, the pilot signal of the variable pressure reducing valve of the fourth embodiment is changed from pressure oil to an electric signal.

The remaining structure and operation are substantially the same as those of the first embodiment.

(Effects of the Invention) 7 Since the present invention has the above-described configuration, it has the same functions and effects as the conventional operation control device for multiple actuators using a single variable displacement pump of the same type, and also has the following effects. is obtained.

(1) In a multiple actuator operation control device in which multiple actuators can be driven simultaneously or individually by a single variable displacement pump, a signal of the selected maximum load pressure of the multiple actuators that commands the operation of the variable displacement pump. Since the circuit is provided with a second relief valve or a pressure reducing valve that can be operated at a set pressure lower than the relief pressure of the signal circuit, by operating the second relief valve or pressure reducing valve in a timely manner, one of the multiple actuators operating in parallel can be controlled. Even when the operation of the actuator is stopped, stable operation can be performed without fear of sudden changes in the speeds of other actuators.

(2) If the second relief valve provided in the signal circuit is an electromagnetic proportional relief valve, by adjusting the relief pressure of the electromagnetic proportional relief valve in a timely manner, some of the multiple actuators operating in parallel (high pressure actuator) Even when the operation of the actuator is stopped, there is no risk of sudden changes in the speed of the remaining (low pressure) actuator.

(3) If the signal circuit is provided with a pressure reducing valve that reduces the relief pressure of the signal circuit in a timely manner using a hydraulic signal or an electrical signal, the pressure reducing valve can be operated to reduce the pressure in a timely manner using a hydraulic signal or an electrical signal. , during simultaneous movement of multiple actuators. When some actuators are stopped, there is no risk of sudden speed changes of the low-pressure actuators.

(4) If a second relief valve with a low relief pressure is provided via a second switching valve in the second signal circuit branching from the signal circuit that commands the operation of the variable displacement pump, switching operation of the second switching valve is possible. Accordingly, the discharge amount of the variable displacement pump can be adjusted by the relief pressure of the second relief valve, and even if the operation of some of the plurality of actuators operating in parallel is stopped, there is no risk of sudden changes in the speeds of other actuators.

(5) By closing the second switching valve 72 provided in the second switching device branching from the signal circuit, it is possible to increase the discharge pressure of the variable displacement pump to the setting of the main relief valve 63. When driving the left and right travel motors 3.4, the required high output is obtained.

(6) If the second switching valve of the second signal circuit has an automatic operating structure such as an electromagnetic or hydraulic type that responds to the operation of an actuator such as a swing motor, the switching of the second switching valve of the second switching device There is no risk of forgetting to operate (7) An electromagnetic proportional relief valve or pressure reducing valve that operates in a timely manner is provided in the signal circuit of the operation control device for multiple actuators using an existing variable displacement pump, or a The operation control device for multiple actuators using a single variable displacement pump of the present invention can be implemented by a simple structural change of just providing a second switching valve and a second relief valve in the two-signal circuit.

[Brief explanation of drawings]

The drawings show an embodiment of the operation control device for multiple actuators using a single variable displacement pump according to the present invention, and FIG. 1 is an explanatory diagram of the control circuit of the first embodiment, and FIG. 2 is an explanation of its characteristic curve. 3 are explanatory diagrams of a second signal circuit according to a second embodiment of the present invention, and FIGS. 4 to 6 are explanatory diagrams of control circuits according to third to fifth embodiments of the present invention. 1...Fork (packet) cylinder, 5...
...Swivel motor. 11-17... Directional switching valve, 21A-26A... Relief valve, 21B-26
B...Relief valve, 31-36...
...Convensator valve, 42-48...Shuttle valve, 51...Variable displacement pump, 55.58...Horsepower (pressure) control valve, 57...
...Flow control valve, 61.Old...Discharge circuit, 62
...Discharge circuit, 65...Signal circuit, 71.91...Second signal circuit, 72.8
2... Second switching valve, 73... Second relief valve, 92... Electromagnetic proportional relief valve, 101...
...Pressure reducing valve (variable pressure type), 111...Pressure reducing valve (electromagnetic variable pressure type).

Claims (4)

[Claims] (1) A plurality of actuators are connected in parallel to the discharge circuit of a single variable displacement pump via a directional control valve with a compensator valve, and the maximum load pressure of each of the actuators selected by the shuttle valve and the variable displacement pump In the control device that controls the operation of the plurality of actuators by adjusting the discharge capacity of the variable displacement pump in comparison with the discharge pressure of the selected maximum load pressure, An operation control device for multiple actuators using a single variable displacement pump, characterized in that a second relief valve or pressure reducing valve with a low set pressure is provided. (2) The single variable displacement pump according to claim (1), wherein the signal circuit is provided with a pressure reducing valve that operates to reduce the pressure signal of the drive circuit of the actuator at appropriate times. Operation control device for multiple actuators. (3) A plurality of actuators are connected in parallel to the discharge circuit of a single variable displacement pump via a directional control valve with a compensator valve, and the maximum load pressure of each of the actuators selected by the shuttle valve and the variable displacement pump In the control device that controls the operation of the plurality of actuators by adjusting the discharge capacity of the variable displacement pump by comparison with the discharge pressure of the variable displacement pump, the second signal circuit is branched from the signal circuit of the selected highest load pressure. , an operation control device for a plurality of actuators using a single variable displacement pump, characterized in that a second relief valve having a set pressure lower than the relief pressure of the actuator is provided in the second signal circuit via a second switching valve. . (4) Claim (3) characterized in that the second relief valve provided in the second signal circuit is configured as an electromagnetic proportional relief valve so that its relief pressure can be adjusted.
A device for controlling the actuation of multiple actuators using a single variable displacement pump as described.