JPH11158941A - Hydraulic driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To freely switch discharge flow rate of a plurality of pumps to confluence/diversion by simple control in a closed center circuit capable of supplying discharge flow rate of a plurality of pumps switched to confluence/ diversion to a plurality of actuators and, at the same time, to control accurate flow rate by simple control irrespective of difference in load pressure of the actuators in the case of composite control. SOLUTION: Pressure control valves 20 and 21 and auxiliary valves 15a, 15b, 16a and 16b for ON/OFF operation are provided to directional control valves 9 and 10, and the auxiliary valves are switched in accordance with control conditions and switch confluence/diversion of pressure oil from pumps 1a and 1b. Signal selector valves 15c, 15d, 16c and 16d monolithically formed of the auxiliary valves are provided, and linkage with the maximum load pressure sensing lines 32a, 32b and load pressure sensing lines 40a, 41a and 40b and 41b of actuators 3 and 4 is switched by the signal selector valves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic drive device provided in a hydraulic machine such as a hydraulic excavator that drives a plurality of actuators by a plurality of hydraulic pumps, and more particularly to a hydraulic circuit having a closed center type directional control valve group. The present invention relates to a hydraulic drive device capable of combining and branching discharge flow rates of a plurality of pumps and supplying the combined flow rates to a plurality of actuators.

[0002]

2. Description of the Related Art A hydraulic drive device capable of joining / dividing discharge flow rates of a plurality of pumps and supplying them to a plurality of actuators by a hydraulic circuit having a closed center type directional control valve group (hereinafter, appropriately referred to as a "closed center circuit"). Japanese Unexamined Patent Application Publication No. 6-40406 and Japanese Unexamined Patent Application Publication No. 9-79212 disclose such methods. FIG. 13 shows a hydraulic drive device described in Japanese Utility Model Laid-Open No. 6-40406.

In FIG. 13, the capacity of a variable displacement hydraulic pump (hereinafter referred to as a pump) 201a, 201b is controlled by regulators 202a, 202b, respectively. The pump 201a is connected to a group of actuators (actuators 203 and 204), and these actuator groups are driven by pressure oil discharged from the pump 201a. Closed center type directional control valves 209 and 210 are provided between the pump 201a and the actuator group, and the direction and the flow rate of each pressure oil sent from the pump 201a to the actuator group are switched and controlled. The pump 201b includes an actuator group (actuator 20).
5, 206), and these actuator groups are driven by pressure oil discharged from the pump 201b. Similarly, closed center type directional control valves 211 and 212 are provided between the pump 201b and these actuator groups, and the direction and flow rate of each pressure oil sent from the pump 201b to the actuator groups are switched and controlled.

[0004] Between the discharge circuit 230a of the pump 201a and the discharge circuit 230b of the pump 201b, there is provided a joining / dividing switching valve 226. As a switching control system of the joining / dividing switch valve 226, operating levers 280, 281 are used. The switching method is adopted according to the operation status of. That is, the operation signals of the operation levers 280 and 281 are transmitted to the controller 284.
And the direction control valves 209, 210, 211, 212
And branching switching valve 22 according to the detection result of the switching control status of
6, the pumps 201a, 201b
Of the discharge circuits 230a and 230b are joined and divided to supply pressure oil to the actuator. As another method, a state where one of the pump discharge circuits cannot supply the required flow rate of the actuator (referred to as a saturation state) is detected.
Based on the detection result, the discharge circuits 230a and 230b of the pumps 201a and 201b may be combined and divided to supply the pressure oil to the actuator.

In FIG. 13, 220, 221, 222, 22
Reference numeral 3 denotes a pressure control valve for performing load compensation.
1b is a pump discharge pressure sensing line, and 232
a, 232b are the maximum load pressure sensing lines,
235a and 235b are load sensing control valves,
236 is a signal switching valve.

Japanese Patent Application Laid-Open No. 9-79212 discloses that at least two hydraulic pumps, first and second,
At least two actuators, a first closed-center directional control valve connected to the first and second hydraulic pumps for controlling the flow rate of pressure oil supplied to the first actuator, and at least the first A second closed center type directional control valve connected to the hydraulic pump and controlling the flow rate of the pressure oil supplied to the second actuator. First and second feeder lines for connecting the first and second hydraulic pumps are provided, and auxiliary valves controlled by a proportional solenoid valve are provided on the first and second feeder lines, respectively. It describes that the discharge flow rates of two hydraulic pumps are switched between merging and branching and the degree of merging is controlled by controlling the degree of throttle and the degree of restriction. Here, the switching of the auxiliary valve is controlled in accordance with the operation state of the operation lever. That is, the operation signal (pilot pressure) of the operation lever is detected, the detection signal is input to the controller, and the operation state of the operation lever is determined to control the opening / closing of the auxiliary valve and the degree of throttle. As a result, the merging circuit and the priority circuit can be realized with a simple structure in the closed center circuit hydraulic system, and the priority and the metering characteristics in the combined operation of the actuators can be independently set.

[0007]

However, the above prior art has the following problems.

In the prior art described in Japanese Utility Model Laid-Open Publication No. 6-40406 shown in FIG. 13, when the actuator 203 and the actuator 204 are operated in a combined operation, the discharge from the pump 201a is set by setting the merge / divide flow switching valve 226 to the branch position. It is possible to switch between supplying the flow rate and supplying the discharge flow rates of the pumps 201a, 201b by setting the merge / divide switch valve to the merge position. However, when the difference between the load pressures of the actuators 203 and 204 is large, considering the independence of the actuator operation during the combined operation, it is necessary to supply the flow rates to the actuators 203 and 204 separately from the pumps 201a and 201b. Is desirable. Such supply of the pressure oil cannot be realized by the switching control of the merge / shunt switching valve as shown in FIG.

The pumps 201a and 201b have different dischargeable capacities.
In the case where the maximum flow rate of 01b is smaller, and when the required flow rate of the actuator 205 is larger than that of the actuator 203 in the combined operation of the actuator 203 and the actuator 205, the discharge flow rate of the pump 201a is supplied to the actuator 205, It is desirable to supply the discharge flow rate of the pump 201b to the actuator 203. Such supply of pressure oil cannot be realized by the switching control of the merge / shunt switching valve as shown in FIG.

In the prior art described in Japanese Patent Application Laid-Open No. 9-79212, a considerably complicated merging is achieved by controlling the opening / closing of an auxiliary valve provided on a feeder line of a directional control valve and the degree of throttle in accordance with the operating condition of an operating lever.・ Switching control of branch flow is possible. However, the control of the degree of throttle of the auxiliary valve is proportional control, and the control is complicated.

Further, since load compensation is not performed in the flow control of the directional control valve and the auxiliary valve, when there is a difference between the load pressures of the two actuators in a combined operation in which the pressure oil is supplied to the two actuators from the same pump. However, there is also a problem that a large amount of pressure oil is supplied to the actuator on the low pressure side, and the flow rate cannot be controlled in accordance with the ratio of the operation amount (required flow rate) of the operation lever.

Here, in order to compensate the load in the hydraulic system described in Japanese Patent Application Laid-Open No. 9-79212, it is sufficient to detect the load pressure of the actuator and control the degree of throttle of the auxiliary valve, but the load pressure frequently increases. Because of the change, it is extremely difficult to control the degree of aperture, and it is difficult to put it to practical use.

SUMMARY OF THE INVENTION An object of the present invention is to provide a closed center circuit in which the discharge flow rates of a plurality of pumps can be combined and divided and supplied to a plurality of actuators. It is another object of the present invention to provide a hydraulic drive device capable of performing accurate flow control with simple control regardless of a difference in load pressure of an actuator in a combined operation.

[0014]

(1) In order to achieve the above object, the present invention provides at least a first and a second at least two hydraulic pumps, and the pressure discharged by the first and the second hydraulic pumps. A hydraulic actuator group driven by oil, a closed center type directional control valve group for controlling a flow of hydraulic oil supplied from the first and second hydraulic pumps to the hydraulic actuator group, and the first hydraulic pressure Means for detecting a first maximum load pressure which is the highest load pressure among the load pressures of the actuator group to which the pump supplies the pressure oil, and a load pressure of the actuator group to which the second hydraulic pump supplies the pressure oil. Means for detecting a second maximum load pressure, which is the maximum load pressure, and an actuator group which is provided in each of the directional control valve groups and operates by the first and second maximum load pressures In the hydraulic drive system including a pressure control valve unit which enables the flow rate distribution of the first and second
A first position for supplying only the pressure oil from the first hydraulic pump and a second position for supplying only the pressure oil from the second hydraulic pump, which is disposed between the hydraulic pumps and the respective directional control valves. An auxiliary valve group that can be switched on / off to any one of a third position in which the hydraulic oil from the first and second hydraulic pumps is joined and supplied, and the first maximum load pressure is set to a first position. Pressure control valve group related to the actuator group to which the hydraulic oil is supplied from the hydraulic pump, and the second maximum load pressure to the pressure control valve group related to the actuator group to which the hydraulic oil is supplied from the second hydraulic pump. A signal switching valve group switchable in conjunction with the auxiliary valve group and a switching position pattern of the auxiliary valve group are determined so as to guide the auxiliary valve group, and the auxiliary valve group is turned on / off so as to obtain this pattern. Off for automatic switching control Shall and control means.

The auxiliary valve group disposed between the first and second hydraulic pumps and each directional control valve can be switched on and off, so that the control is simple and the auxiliary valve group is switched. By performing the on / off switching control by the control means, it is possible to freely switch the merging / dividing of the discharge flow rates of a plurality of pumps with simple control.

Further, since the auxiliary valve is provided for the directional control valve with load compensation by the pressure control valve, even in the case of simple control that only switches the auxiliary valve on and off, two operations are required in a combined operation. Accurate flow control can be performed according to the ratio of the operation amount (required flow rate) of the operation lever regardless of the difference in the load pressure of the actuator.

(2) In the above (1), preferably,
The switching control means includes: a command means group for outputting a command signal for operating the direction control valve group; and a command signal from the command means group for switching the auxiliary valve group in accordance with an operation state of the actuator group. Means for determining a position pattern.

[0018] Thus, it is possible to freely switch the merging / shunting of the discharge flow rates of the plurality of pumps in accordance with the operation status of the actuator.

(3) In the above (1), preferably, the switching control means includes a command means group for outputting a command signal for operating the directional control valve group, and a setting signal for a working mode of the actuator group. And a means for inputting a command signal from the commanding means group and a setting signal from the setting means to determine a switching position pattern of the auxiliary valve group in accordance with an operation state of the actuator group. Have.

Thus, it is possible to freely switch between the merging and branching of the discharge flow rates of the plurality of pumps in accordance with the operation state of the actuator and in consideration of the setting state of the mode of the setting means.

(3) Further, in the above (1), preferably, the switching control means includes a command means group for outputting a command signal for operating the directional control valve group, and a work mode setting signal for the actuator group. And a pressure sensor group for detecting a load pressure of the actuator group, a command signal from the command means group, a setting signal from the setting means, and a detection signal from the pressure sensor group. Means for determining a switching position pattern of the auxiliary valve group according to the operation state of the actuator group.

With this arrangement, it is possible to freely switch the merging / shunting of the discharge flow rates of a plurality of pumps in accordance with the operation state of the actuator and in consideration of the setting state of the mode of the setting means and the load state of the actuator.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

First, a first embodiment of the present invention will be described with reference to FIGS.

In FIG. 1, the hydraulic drive system of the present embodiment comprises first and second variable displacement hydraulic pumps 1a, 1b.
And actuators 3 and 4 driven by pressure oil discharged from the pumps 1a and 1b, and closed-center directional control valves 9 and 10 for switching and controlling the direction and flow rate of each pressure oil sent to the actuators 3 and 4. And pressure control valves 20 and 21 located downstream of the meter-in variable throttles incorporated in the directional control valves 9 and 10.

The direction control valves 9 and 10 are switched by pilot pressure signals 91a and 91b and 101a and 101b, respectively. Also, pilot pressure signals 91a, 91
There are provided pressure sensors 92a, 92b and 102a, 102b for detecting the pressures of 1b, 101a, 101b.

The pressure control valves 20, 21 are installed downstream of the meter-in variable throttles of the respective directional control valves, and are operated by the highest load pressures (described later) led to the control lines 50a, 50b and 51a, 51b, and are operated by the meter-in. This is a load compensation valve that controls the outlet pressure of the variable throttle to be substantially equal to the maximum load pressure.

Auxiliary valves 15a and 15b are provided on the feeder line upstream of the direction control valve 9, and the auxiliary valves 15a and 15b
Switching control is performed by a and 151b. Similarly, auxiliary valves 16a and 16b are provided upstream of the direction control valve 10, and the auxiliary valves 16a and 16b are controlled to be switched by pilot pressure signals 161a and 161b, respectively.

Auxiliary valves 15a, 16a, 15b, 16
Reference numeral b denotes an on / off opening / closing valve which is fully opened at the position A and fully closed at the position B.

A pump discharge pressure sensing line 31a for detecting a discharge pressure of the pump 1a, a maximum load pressure sensing line 32a for detecting a maximum load pressure of an actuator supplied with a discharge flow rate from the pump 1a, and a discharge pressure of the pump 1b. And a maximum load pressure sensing line 32b for detecting the maximum load pressure of the actuator to which the discharge flow rate from the pump 1b is supplied.

The sensing lines 31a and 32a are connected to a load sensing control valve 35a for controlling the discharge flow rate of the pump 1a by load sensing control, and the load sensing control valve 35a controls the regulator 2a.
Performs tilt control of the pump 1a such that the discharge pressure of the pump 1a becomes higher than the maximum load pressure detected by the sensing line 32a by a predetermined value. Similarly, the sensing lines 31b and 32b are connected to a load sensing control valve 35b for controlling the discharge flow rate of the pump 1b by load sensing control, and the regulator 2b senses the discharge pressure of the pump 1b by the load sensing control valve 35b. The tilt control of the pump 1b is performed so as to be higher than the maximum load pressure detected by the line 32b by a predetermined value.

The load pressure sensing line 40a of the actuator 3 is connected to the maximum load pressure sensing line 32a via a signal switching valve 15c integrated with the check valve 60a and the auxiliary valve 15a, and the check valve 61a and the auxiliary valve 16a. Signal switching valve 16c integral with
The load pressure sensing line 41a of the actuator 4 is connected via the. The maximum load pressure sensing line 32a is connected to the signal switching valve 15c and the check valve 7
0a, is connected to the pressure control valve control line 50a via the signal switching valve 16c and the check valve 71a, and is connected to the pressure control valve control line 51a. Are connected to the pressure receiving chambers of the pressure control valves 20 and 21.

Similarly, the check valve 60b and the auxiliary valve 15b are connected to the maximum load pressure sensing line 32b.
The load pressure sensing line 40b of the actuator 3 is connected via a signal switching valve 15d integrated with
The load pressure sensing line 41b of the actuator 4 is connected via a signal switching valve 16d integrated with the check valve 61b and the auxiliary valve 16b. The maximum load pressure sensing line 32b is connected to the pressure control valve control line 50b via the signal switching valve 15d and the check valve 70b, and is connected to the signal switching valve 16d and the check valve 71b.
The pressure control valve control lines 51b are connected to the pressure control valve control lines 51b via the b, and the pressure control valve control lines 50b and 51b are connected to the pressure receiving portions of the pressure control valves 20 and 21, respectively.

Signal switching valves 15c, 16c, 15d, 16
d denotes auxiliary valves 15a, 16a, 15b, 16 respectively.
b in conjunction with the auxiliary valves 15a, 16a, 15
The opening / closing valve is fully open at the position A of b and 16b and fully closed at the position B.

The operation of the signal switching valve by switching the position of the auxiliary valve will be described.

It is assumed that the pump 1a supplies a flow rate to the actuators 3 and 4, and the pump 1b supplies a flow rate only to the actuator 3. To make this state,
The auxiliary valves 15a, 15b, 16a are controlled to be switched to the A position, and the auxiliary valve 16b is switched to the B position. At this time, by switching the auxiliary valves 15a, 16a to the position A, the signal switching valves 15c, 16c are fully opened, and the load pressure detection line 40
a and 41a are communicated with the maximum load pressure detection line 32a.
The higher load pressure of the actuators 3, 4 to which the pressure oil from a is supplied is selected and guided by the check valves 60a, 61a. Similarly, when the auxiliary valve 15b is switched to the position A, the signal switching valve 15d is fully opened and the load pressure detection line 40b is connected to the maximum load pressure detection line 32b. The load pressure of the actuator 3 to which the pressure oil from 1b is supplied is selected and guided by the check valve 60b.

The auxiliary valves 15a, 15b, 16a
Is switched to the position A by switching the signal switching valves 15c, 15
d and 16c are fully opened, the maximum load pressure detection line 32a is communicated with the pressure control valve control lines 50a and 51a, and the maximum load pressure detection line 32b and the pressure control valve control line 5 are connected.
0b is communicated. Here, when the load pressure of the actuator 3 is higher than the load pressure of the actuator 4,
Since the highest load pressure sensing line 32a and the highest load pressure sensing line 32b have the same pressure, the check valves 70a, 71a, 70b control the pressure control valves 20,2.
1 is controlled by the load pressure of the actuator 3. That is, load compensation is performed so that the outlet pressures of the meter-in variable throttles of the directional control valves 9 and 10 are both substantially equal to the load pressure of the actuator 3.

When the load pressure of the actuator 4 is higher than the load pressure of the actuator 3, the maximum load pressure sensing line 32a has a higher pressure than the maximum load pressure sensing line 32b. The pressure control valves 20 and 21 are controlled by the load pressure of the actuator 4 by 71a. That is, the load compensation is performed so that the outlet pressures of the meter-in variable throttles of the direction control valves 9 and 10 are both substantially equal to the load pressure of the actuator 4.

Next, the auxiliary valves 15a, 15b, 16
The configuration of the switching control between a and 16b will be described.

In FIG. 2, an operation lever 80 is an operation lever for the actuator 3. When the operation lever 80 is operated, pilot pressure signals 91a and 91b are generated according to the operation direction and the operation amount, and the direction control valve 9 is operated. Control switching. Similarly, the operation lever 81 is an operation lever for the actuator 4, and when the operation lever 81 is operated, the pilot pressure signal 10 is controlled according to the operation direction and the operation amount.
1a and 101b are generated, and the direction control valve 10 is switched and controlled.

Auxiliary valves 15a, 15b, 16a, 16
b and the signal switching valves 15c, 15d, 16c, 16d (hereinafter represented by auxiliary valves 15a, 15b, 16a, 16b) are controlled by the controller 84 in FIG. As shown in FIG. 3, the controller 84 includes an input unit 84a, a recording unit 84b that stores preset characteristics, an operation unit 84c that reads the characteristics from the storage unit 84b and performs a predetermined operation, Arithmetic unit 84
an output unit 84d that converts the command signal calculated in step c into a drive signal and outputs the drive signal. The controller 84 includes a pressure sensor 92a for detecting the pilot pressure signal,
Signals from 92b and 102a, 102b, pressure sensors 93, 103 provided on the load pressure sensing lines 40a, 41a for detecting the load pressure of the actuators 3, 4 and a work mode setting button 83 are given, and an input section 84a
A / D convert these signals and input them. Output unit 84
d denotes a drive signal from the electromagnetic proportional pressure reducing valves 85a, 85b, 86
a, 86b to output the pilot pressure signal 151a, 1
51b, 161a and 161b are generated, and the auxiliary valve 15a is switched by the pilot pressure signal 151a, the auxiliary valve 15b is switched by the pilot pressure signal 151b, the auxiliary valve 16a is switched by the pilot pressure signal 161a, and the auxiliary valve 16b is switched by the pilot pressure signal 161b. Control.

The storage unit 84b of the controller 84 stores a program for executing a processing procedure as shown in FIG. 4, for example. Hereinafter, with reference to FIG.
An example of switching control of a, 15b, 16a, and 16b will be described.

<Case 1> When the actuator 3 or 4 is normally driven alone.

When an operation signal for only the actuator 3 is input from the operation lever 80, the auxiliary valve 15
The positions a and 15b are respectively set to the position A so that the pumps 1a and 1b can be joined to supply the pressure oil (step S1 →
S2 → S3 → S14). Thereby, the actuator 3
The maximum supply flow rate to the can be increased. Similarly,
When the operation signal of only the actuator 4 is input from the operation lever 81, the auxiliary valves 16a and 16b are respectively set to the A position, and the pumps 1a and 1b are joined to supply the pressure oil (step S1 → S2 → S4 → S5 →
S12). Thereby, the maximum supply flow rate to the actuator 4 can be increased.

<Case 2> When the actuator 3 or 4 is independently driven by a minute operation.

When an operation signal for only the actuator 3 is input from the operation lever 80 and the operation amount is small, the auxiliary valve 15a is set to the A position, the auxiliary valve 15b is set to the B position, and the pump 1a is operated. Only the pressurized oil can be supplied (step S1 → S2 → S3 → S
15). Similarly, when the operation signal of only the actuator 4 is input from the operation lever 81, and the operation amount is small, the auxiliary valve 16a is set to the A position, the auxiliary valve 16b is set to the B position, and the pump 1a is turned on. (Step S1 → S2 → S4 →
S5 → S13). Thus, Case 3
The same effects as those described later can be obtained.

<Case 3> When both the actuators 3 and 4 are driven, the fine operation mode is selected by the work mode setting button 83, and fine operation is required for driving the actuator.

Under these conditions, the supply flow rate to the actuator can be reduced, so that the flow rate supply to the actuators 3 and 4 is made only from the pump 1a and the auxiliary valve 15
a is position A, 15b is position B, 16a is position A, 16b
Is the B position (step S1 → S6 → S21). By doing so, the pump 1b only needs to be driven with the minimum tilt, or the pump 1b can be stopped.
Energy efficiency of the entire hydraulic system is improved. Especially 2
In a system in which two pumps are driven by different engines, the speed of one of the engines can be reduced, thereby improving fuel efficiency.

<Case 4> When both the actuators 3 and 4 are driven and the differential pressure between the pressure sensors 93 and 103 for detecting the load pressures of the actuators 3 and 4 is large, that is, the load pressure of the actuators 3 and 4 When the difference is large.

Under these conditions, the auxiliary valve is switched to a flow supply position from the pump 1a to the actuator 3 and from the pump 1b to the actuator 4. That is, the auxiliary valve 15a is at the position A, the auxiliary valve 15b is at the position B,
The auxiliary valve 16a is switched to the B position and the auxiliary valve 16b is switched to the A position (steps S1 → S6 → S7 → S20).
By doing so, a state in which the discharge flow rate of the pump depends on the larger load pressure difference and the higher load pressure (PQ
Even in the state of being stuck in the diagram, the flow rate can be firmly supplied to the actuator having a low load pressure but requiring a large flow rate.

<Case 5> When the actuator 3 is driven by a small operation and the actuator 4 is also driven by a small operation.

Under these conditions, the actuators 3,
Actuator 3, because the supply flow to 4 is small.
4 is supplied only from the pump 1a, the auxiliary valve 15a is at the A position, the auxiliary valve 15b is at the B position, the auxiliary valve 16a is at the A position, and the auxiliary valve 16b is at the B position (step S1 → step S6 → step S7 → Step S8 → Step S10 → Step S19). The effect is
Same as Case 3.

<Case 6> When the actuator 3 is driven by a minute operation and the actuator 4 is driven normally.

Under these conditions, the supply flow rate to the actuator 3 is small, and it is desired to supply a large flow rate to the actuator 4. Therefore, the flow rate supply to the actuator 3 is made only from the pump 1a. , The auxiliary valve is switched so that the flow rate can be supplied by merging the two pumps 1a and 1b. That is, the auxiliary valve 15a is at the position A, the auxiliary valve 15b is at the position B,
The auxiliary valve 16a is set to the A position, and the auxiliary valve 16b is set to the A position (Step S1 → Step S6 → Step S7 →
Step S8 → Step S10 → Step S18).

<Case 7> When the actuator 3 is driven normally and the actuator 4 is driven by a minute operation.

Under this condition, it is desired that a large flow rate be supplied to the actuator 3 and a small flow rate is supplied to the actuator 4. Therefore, the flow rate is supplied to the actuator 3 by a combination of the two pumps 1a and 1b. The auxiliary valve is switched so that the supply flow rate to the actuator 4 can be made only from the pump 1a. That is, the auxiliary valve 15a is at the position A, the auxiliary valve 15b is at the position A,
The auxiliary valve 16a is at the position A, and the auxiliary valve 16b is at the position B (step S1 → step S6 → step S7 →
Step S8 → Step S9 → Step S17).

<Case 8> When the actuators 3 and 4 are driven normally.

Under these conditions, the actuator 3,
Since it is desired to supply a large amount of flow to the pump 4, the pumps 1a and 1b are joined and the auxiliary valve is switched to a position where the flow can be supplied to the actuators 3 and 4. That is, the auxiliary valve 15a is set to the A position, the auxiliary valve 15b is set to the A position, the auxiliary valve 16a is set to the A position, and the auxiliary valve 16b is set to the A position (step S1 → step S6 → step S7 → step S8 → step S9 → step S16). .

As described above, according to the present embodiment, it is possible to freely switch between the merging and branching of the discharge flow rates of a plurality of pumps with a simple control, and in a combined operation, regardless of the load pressure of the actuator. Accurate flow control can be performed with simple control.

Further, it is possible to freely switch the merging / shunting of the discharge flow rates of a plurality of pumps in accordance with the operation state of the actuator and in consideration of the setting state of the mode of the setting means and the load state of the actuator.

A second embodiment of the present invention will be described with reference to FIG. In FIG. 5, members that are the same as the members illustrated in FIG. 1 are given the same reference numerals, and descriptions thereof will be omitted.

In this embodiment, the functions of the auxiliary valves 15a and 15b in FIG. 1 of the above embodiment are replaced with the auxiliary valve 15 which is a three-position switching valve, and the auxiliary valves 16a and 16b are replaced.
The function b is replaced by an auxiliary valve 16 which is a three-position switching valve.

That is, the auxiliary valve 15 has three positions A, B, and C, and the signal switching valves 15Ac, 15A
d also has three switching positions, and the auxiliary valve 15 and the signal switching valves 15Ac and 15Ad
When switched to the position, the auxiliary valve 15 in FIG.
a and the signal switching valve 15c, when the auxiliary valve 15b is switched to the A position and the auxiliary valve 15b is switched to the A position.
When the auxiliary valve 15 is switched to the position A, the auxiliary valve 15a in FIG.
Position, auxiliary valves 15a and 15b and signal switching valves 15c and 15d when the auxiliary valve 15b is switched to the B position.
When the auxiliary valve 15 is switched to the position B, the auxiliary valve 15a in FIG.
The same function as the auxiliary valves 15a and 15b and the signal switching valves 15c and 15d when the auxiliary valve 15b is switched to the position A is performed.

Similarly, A, B, C
And the signal switching valves 16Ac,
The 16Ad also has three switching positions, and these auxiliary valves 1
6 and the signal switching valves 16Ac and 16Ad are the auxiliary valves 1
6 is switched to the C position, the auxiliary valves 16a and 16b and the signal switching valve 1 when the auxiliary valve 16a is switched to the A position and the auxiliary valve 16b is switched to the A position in FIG.
Performs the same function as 6c and 16d, and sets the auxiliary valve 16 to A
When switched to the position, the auxiliary valve 16 in FIG.
a, the auxiliary valves 16a, 16b and the signal switching valve 16c, when the auxiliary valve 16b is switched to the B position.
When the auxiliary valve 16 is switched to the position B, the auxiliary valve 16a in FIG.
Position, auxiliary valves 16a, 16b and signal switching valves 16c, 16d when auxiliary valve 16b is switched to position A
Performs the same function as.

According to this embodiment configured as described above, the same effect as that of the first embodiment shown in FIG. 1 can be obtained.

In this embodiment, since the auxiliary valve for each direction control valve is integrated into one, the configuration of the hydraulic circuit is simplified.

A third embodiment of the present invention will be described with reference to FIGS. In FIG. 6, members that are the same as the members illustrated in FIG. 1 are given the same reference numerals, and descriptions thereof will be omitted.

In the present embodiment, a positive flow rate control is used as a pump control method for a variable displacement pump in a closed center circuit.

In FIG. 6, a bypass passage 57 extending from the discharge circuits 30a, 30b of the pumps 1a, 1b to the tank is provided.
a, 57b are branched, and the bypass passages 57a, 57b
Are provided with bleed valves 27a and 27b, respectively.

The bleed valves 27a and 27b are controlled by the controller 84A so that the opening degree becomes narrower from the fully opened state as the operation amount of the operation levers 80 and 81 increases. At this time, the operation amount of the operation levers 80 and 81 may be the sum or the maximum value thereof, or may be determined by calculating by some function. Further, the auxiliary valve 15
a, 15b and 16a; the ratio of the required flow rate to the pump 1a to the required flow rate to the pump 1b is calculated from the switching status of the 16b, and the sum of the manipulated variables is divided by the ratio to obtain the pump 1a.
And a portion relating to the pump 1b.

The positive control valve 3 is provided to the pumps 1a and 1b.
5Aa and 35Ab are provided, and the positive control valves 35Aa and 35Ab are also controlled by the controller 84A according to the operation amounts of the operation levers 80 and 81 when the actuator 3 or 4 is driven independently and when the actuators 3 and 4 are combined and driven. 1b is controlled so as to discharge the required amount of pressure oil.

FIG. 7 is a functional block diagram showing an example of the processing performed by the controller 84A.

In FIG. 7, pressure sensors 92a and 92b
The operation status of the actuator 3 is determined based on the signal from the controller, and the signal corresponding to the actuator in the operation state is selected from the signals from the pressure sensors 92a and 92b (block F1). Similarly, the pressure sensors 102a, 10
The operation state of the actuator 4 is determined based on the signal from 2b, and the signal corresponding to the actuator in the operation state is selected from the signals from the pressure sensors 102a and 102b (block F2).

Next, since the actuator for supplying the pressure oil from the pump 1a is determined by the switching state of the auxiliary valves 15a and 16a, the switching state of the auxiliary valves 15a and 16a is grasped from the internal information of the controller 84A. , The pressure sensors 92a, 92b and 102a,
A signal corresponding to the actuator supplying the pressure oil from the pump 1a is selected from the signals from 102b (blocks F3 and F4), and the larger one of the signals is selected (block F7). To perform control calculations,
The target opening of the bleed valve 27a is calculated (block F
8).

Similarly, for the tilt control of the pump, a signal corresponding to the actuator for supplying the pressure oil from the pump 1a is selected from the signals from the pressure sensors 92a and 92b and 102a and 102b (blocks F3 and F4). The required flow rate is calculated for each actuator in accordance with this signal (blocks F9 and F10), the sum of the calculated flow rates is obtained (block F11), and a control operation is performed in accordance with this value to obtain the target tilt of the pump 1a. Calculate the roll (Block F
12).

Similarly, since the actuator for supplying the pressure oil from the pump 1b is determined by the switching state of the auxiliary valves 15b and 16b, the switching state of the auxiliary valves 15b and 16b is grasped from the internal information of the controller 84A, and this switching is performed. Pressure sensors 92a, 92b and 10 depending on the situation
From the signals from 2a and 102b, a signal corresponding to the actuator supplying the pressure oil from the pump 1b is selected (blocks F5 and F6), and the larger one of the signals is selected (block F13). , And the target opening of the bleed valve 27b is calculated (block F14).

Similarly, for the tilt control of the pump, a signal corresponding to the actuator for supplying the pressure oil from the pump 1b is selected from the signals from the pressure sensors 92a and 92b and 102a and 102b (blocks F5 and F6). According to this signal, the required flow rate is calculated for each actuator (blocks F15 and F16), the sum of the calculated flow rates is obtained (block F17), and a control operation is performed according to this value to perform the target tilt of the pump 1b. Inversion is calculated (block F18).

The target opening and target tilt obtained as described above are converted into drive signals, respectively, and output to the electromagnetic proportional pressure reducing valves 87a, 87b, 88a, 88b shown in FIG. 6 to generate pilot pressure signals. , The bleed valve 27a and the positive flow control valve 3
5Aa, bleed valve 27b and positive flow control valve 3
The switching control of each of the 5 Abs is performed.

As described above, according to the present embodiment, the present invention is applied to a hydraulic system that employs positive flow control as a pump control method in a closed center circuit,
An effect similar to that of the first embodiment shown in FIG. 1 is obtained.

Although the auxiliary valve in this embodiment is the same as that shown in FIG. 1, a similar effect can be obtained by using the auxiliary valve shown in FIG.

A fourth embodiment of the present invention will be described with reference to FIG. In FIG. 8, members that are the same as the members shown in FIGS. 1 and 6 are given the same reference numerals, and descriptions thereof will be omitted.

This embodiment uses negative flow rate control as a pump control method for a variable displacement pump in a closed center circuit.

In FIG. 8, a bypass passage 57 extending from the discharge circuits 30a, 30b of the pumps 1a, 1b to the tank is provided.
a, 57b are branched, and the bypass passages 57a, 57b
Are provided with bleed valves 27a and 27b, respectively. In addition, the bleed valve 2 of the bypass passages 57a and 57b
The throttles 28a, 28b for generating the control pressure are provided downstream of the throttles 7a, 27b.
Pressure sensing lines 33a and 33b, which are lines for detecting the control pressure, are connected upstream of b. The pressure sensing lines 33a and 33b are led to negative flow control valves 35Ba and 35Bb, and the negative flow control valves 35Ba and 35Bb perform negative flow control based on the control pressure values detected by the pressure sensing lines 33a and 33b. The pump tilting position is controlled by 2a and 2b, and the pumps 1a and 1b discharge a flow rate.

The bleed valves 27a and 27b are controlled by a controller 84B as in the embodiment shown in FIG.

As described above, according to the present embodiment, the present invention is applied to a hydraulic system employing negative flow rate control as a pump control method in a closed center circuit,
An effect similar to that of the first embodiment shown in FIG. 1 can be obtained.

In this embodiment, the auxiliary valve is the same as that shown in FIG. 1. However, the same effect can be obtained by using the auxiliary valve shown in FIG.

FIGS. 9 and 10 show a fifth embodiment of the present invention.
This will be described below. 9 and 10, the same reference numerals are given to the same members as those shown in FIG. 1, and the description is omitted.

In the present embodiment, the present invention is applied to a hydraulic system using a closed center circuit of a hydraulic shovel.

In FIGS. 9 and 10, actuators 3, 4, 5, 6, 7, and 8 are a boom cylinder, a bucket cylinder, an arm cylinder, a swing motor, a first travel motor, and a second travel of a hydraulic shovel, respectively. The direction and flow rate of each pressure oil sent to the actuators 3, 4, 5, 6, 7, 8 are controlled by closed center type directional control valves 9, 10, 11, 12, 13, 14 corresponding to motors. On the downstream side of the meter-in variable throttles of these directional control valves, pressure control valves 20, 21, and 22 for load compensation are provided.
2, 23, 24, and 25 are provided.

The directional control valves 9, 10, 11, 12, 13,
14 are pilot pressure signals 91a; 91b,
101a; 101b, 111a; 111b, 121a;
Switching control is performed by 121b, 131a; 131b, 141a; 141b. Also, the pilot pressure signal 9
1a; 91b, 101a; 101b, 111a; 111
b, 121a; 121b, 131a; 131b, 141
a; pressure sensor 92a for detecting the pressure of 141b;
b, 102a; 102b, 112a; 112b, 122
a; 122b, 132a; 132b, 142a; 142
b is provided.

On the feeder lines upstream of the directional control valves 9, 10, 11, and 13, auxiliary valves 15a; 15b, 16a;
17a; 17b, 18a; 18b are provided, and the auxiliary valves 15a; 15b, 16a; 16b, 17a;
7B, 18a and 18B are pilot pressure signals 1 respectively.
51a; 151b, 161a; 161b, 171a; 1
Switching control is performed by 71b, 181a and 181b.

The highest load pressure sensing line 32a of the actuator group that supplies the pressure oil from the pump 1a has:
A load pressure sensing line 40a for the actuator 3;
A load pressure sensing line 41a for the actuator 4;
A load pressure sensing line 42a for the actuator 5;
A load pressure sensing line 43a for the actuator 6,
The load pressure sensing line 44a of the actuator 7 is connected to the check valves 60a, 61a, 62a, 63a,
64a and auxiliary valves 15a, 16a, 17a, 18a
And a signal switching valve 15c, 16c, 17c, 18c integral with the
The pressure guided to 2a is the check valve 70a, 71a, 7
2a, 73a, 74a and signal switching valves 15c, 16c,
The pressure control valve control lines 50a,
The liquid is guided to 51a, 52a, 53a, and 54a, and is introduced into the pressure receiving chambers of the pressure control valves 20, 21, 22, 23, and 24.

Similarly, the highest load pressure sensing line 32b of the actuator group that supplies the pressure oil from the pump 1b includes the load pressure sensing line 40b of the actuator 3, the load pressure sensing line 41b of the actuator 4, and the load pressure of the actuator 5 The pressure sensing line 42b, the load pressure sensing line 44b of the actuator 7, and the load pressure sensing line 45b of the actuator 8 are check valves 60b, 61b, 62, respectively.
b, 64b, 65b and auxiliary valves 15b, 16b, 1
Signal switching valves 15d, 16d, 17 integral with 7b, 18b
d, 18d, and the pressure guided to the maximum load pressure sensing line 32b is a check valve 70
b, 71b, 72b, 74b, 75b and the signal switching valve 15
The pressure control valves are guided to pressure control valve control lines 50b, 51b, 52b, 54b, and 55b via d, 16d, 17d, and 18d, and are introduced into pressure receiving chambers of the pressure control valves 20, 21, 22, 24, and 25.

The signals from the pressure sensors 92a to 142b for detecting the pilot pressure are supplied to a controller (not shown) in the same manner as in the first embodiment shown in FIG. Switching valve 15c ~
18d (hereinafter represented by auxiliary valves 15a to 18b)
Are switched by this controller.

An example of switching control of the auxiliary valve according to the operation state of the actuator will be described below.

First, when only the boom is driven as a single operation of the front system actuator (boom, arm, bucket), the auxiliary valve 15a is switched to the A position and the auxiliary valve 15b is switched to the A position. By this switching, the boom cylinder 3 is supplied with a flow rate by the pumps 1a and 1b, and the maximum supply flow rate to the boom cylinder 3 can be increased.

Next, regarding the combined operation of the boom and the arm, the auxiliary valve 15a is at the A position, the auxiliary valve 15b is at the B position, the auxiliary valve 17a is at the B position,
To the A position. By this switching, the boom cylinder 3 is supplied with a flow rate to the pump 1a, and the discharge circuit of the pump 1a is load-compensated under the load pressure of the boom. Similarly, the arm cylinder 5 is connected to the pump 1
b, and the discharge circuit of the pump 1b is load-compensated by the load pressure of the arm. Thereby, the independence of the boom cylinder 3 and the arm cylinder 5 can be maintained.

Next, when the swing and the boom are driven as a combined operation of the swing and the front system actuator (boom, arm, bucket), the auxiliary valve 15a
To the B position and the auxiliary valve 15b to the A position. By this switching, the boom cylinder 3 is supplied with a flow rate to the pump 1b, and the discharge circuit of the pump 1b is load-compensated under the load pressure of the boom. Similarly, the flow rate of the swing motor 6 is supplied to the pump 1a, and the discharge circuit of the pump 1a is load-compensated by the load pressure of the swing motor. Thereby, the boom cylinder 3
And the turning motor 5 can be kept independent.

Next, when the driving operation is performed,
The auxiliary valve 18a is switched to the a position and the auxiliary valve 18b is switched to the B position. By this switching, the first traveling motor 7
The flow rate is supplied to the pump 1a, and the discharge circuit of the pump 1a is subjected to load compensation control by the load pressure of the first traveling motor. Similarly, the flow rate of the second traveling motor 8 is supplied to the pump 1b, and the discharge circuit of the pump 1b is load-compensated by the load pressure of the second traveling motor. Thereby, the independence of the first traveling motor 7 and the second traveling motor 8 can be maintained.

Next, when the traveling and the boom are driven as a combined operation of the traveling and the front actuator (boom, arm, bucket), the auxiliary valve 15a
At position A, auxiliary valve 15b at position B, auxiliary valve 18
a is switched to the B position and the auxiliary valve 18b is switched to the A position.
By this switching, the boom cylinder 3 is supplied with a flow rate to the pump 1a, and the discharge circuit of the pump 1a is load-compensated by the load pressure of the boom. Similarly, the swing motors 7, 8 are supplied with a flow rate to the pump 1b,
In addition, the discharge circuit of the pump 1b is subjected to load compensation control by the load pressure of the traveling motor. Thereby, the boom cylinder 3 and the traveling motors 7 and 8 can be kept independent.

As described above, according to the present embodiment, by switching the auxiliary valve depending on the operation state of the actuator, which pump is used to supply the flow rate, and by combining the discharge flow rates from both pumps, the flow rate is supplied. It can be done or set freely.

The pump control method of the variable displacement pump according to the present embodiment uses load sensing control as in the embodiment shown in FIG. 1, but is the pump control method in FIGS. 6 and 8 described above. A positive flow control method or a negative flow control method may be used.

Further, the switching control of the auxiliary valve is not limited to the operation state of the operation lever in the present embodiment, and a work mode setting button is provided similarly to the embodiment in FIG. Alternatively, it is also possible to provide a pressure sensor for detecting the load pressure, and switch between the pressures based on the magnitude of the difference between the load pressures.

FIG. 11 and FIG. 1 show a sixth embodiment of the present invention.
2 will be described. In FIGS. 11 and 12, members that are the same as the members shown in FIGS. 1, 9, and 10 are given the same reference numerals, and descriptions thereof are omitted.

This embodiment is different from the embodiment shown in FIGS. 9 and 10 in that the auxiliary valves 15a; 15b, 16a;
6b, 17a; 17b, 18a; 18b and the signal switching valve 15c; 15d, 16c; 16d, 17c; 17d, 1
8c and 18d are replaced by auxiliary valves 15, 16, 17, 18 and signal switching valves 15Ac; 15Ad, 16Ac; 16Ad, 17 in the same manner as the auxiliary valves and signal switching valves in FIG.
Ac; 17Ad, 18Ac; 18Ad.

According to the present embodiment, FIGS.
The same effects as in the embodiment shown in FIG. In addition, since the auxiliary valves for each directional control valve are combined into one,
The configuration of the hydraulic circuit is simplified as in the embodiment shown in FIG.

The pump control method of the variable displacement pump according to the present embodiment employs the load sensing control as in the embodiment shown in FIG. 1. However, the pump control method shown in FIGS. A certain positive flow rate control method or a negative flow rate control method may be used.

Further, the switching control of the auxiliary valve is not limited to the operation state of the operation lever in the present embodiment, but is provided with a work mode setting button as in the embodiment in FIG. Alternatively, it is also possible to provide a pressure sensor for detecting the load pressure, and switch between the pressures based on the magnitude of the difference between the load pressures.

[0109]

According to the present invention, in a closed center circuit in which the discharge flow rates of a plurality of pumps can be joined and divided and supplied to a plurality of actuators, the discharge flow rates of a plurality of pumps can be freely joined and divided by simple control. Can be switched, and accurate flow control can be performed with simple control regardless of the difference in the load pressure of the actuator during the combined operation.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a hydraulic drive device according to a first embodiment of the present invention.

FIG. 2 is a schematic view of an operation lever device of the hydraulic drive device shown in FIG.

FIG. 3 is a configuration diagram of a controller of the hydraulic drive device shown in FIG.

FIG. 4 is a flowchart showing processing contents in a controller of the hydraulic drive device shown in FIG. 1;

FIG. 5 is a circuit diagram of a hydraulic drive device according to a second embodiment of the present invention.

FIG. 6 is a circuit diagram of a hydraulic drive device according to a third embodiment of the present invention.

7 is a functional block diagram of a part related to a pump control and a bleed valve control among processing contents in a controller of the hydraulic drive device shown in FIG. 6;

FIG. 8 is a circuit diagram of a hydraulic drive device according to a fourth embodiment of the present invention.

FIG. 9 is a part of a circuit diagram showing a hydraulic drive device according to a fifth embodiment when the present invention is applied to a hydraulic shovel.

FIG. 10 shows a fifth example in which the present invention is applied to a hydraulic excavator.
FIG. 6 is a remaining part of the circuit diagram showing the hydraulic drive device according to the embodiment.

FIG. 11 shows a sixth example in which the present invention is applied to a hydraulic excavator.
FIG. 4 is a part of a circuit diagram illustrating a hydraulic drive device according to an embodiment.

FIG. 12 shows a sixth example in which the present invention is applied to a hydraulic excavator.
FIG. 6 is a remaining part of the circuit diagram showing the hydraulic drive device according to the embodiment.

FIG. 13 is a circuit diagram of a hydraulic drive device provided with a combined / divided flow switching device for a plurality of pumps in a closed center system according to the related art.

[Explanation of symbols]

1a, 1b Hydraulic pump 2a, 2b Regulator 3, 4, 5, 6, 7, 8 Hydraulic actuator 9, 10, 11, 12, 13, 14 Directional control valve 15, 15a, 15b, 16, 16a, 16b, 17,
17a, 17b, 18, 18a, 18b Auxiliary valve 15c, 15d, 16c, 16d, 17c, 17d, 1
8c, 18d Signal switching valve 20, 21, 22, 23, 24, 25 Pressure control valve 27a, 27b Bleed valve 28a, 28b Restrictor 30a, 30b Pump discharge circuit 31a, 31b Pump discharge pressure sensing line 32a, 32b Maximum load pressure sensing Line 33a, 33b Pressure sensing line 35a, 35b Load sensing control valve 35Aa, 35Ab Positive flow control valve 35Ba, 35Bb Negative flow control valve 40a, 40b, 41a, 41b, 42a, 42b, 4
3a, 44a, 44b, 45b Load pressure sensing lines 50a, 50b 51a, 51b, 52a, 52b, 53
a, 54a, 54b, 55b Pressure control valve control lines 60a, 60b, 61a, 61b, 62a, 62b, 6
3a, 64a, 64b, 65b, 70a, 70b, 71
a, 71b, 72a, 72b, 73a, 74a, 74
b, 75b Check valve 80, 81 Operating lever 83 Work mode setting button 84 Controller 84a Controller input unit 84b Controller storage unit 84c Controller calculation unit 84d Controller output unit 91a, 91b, 101a, 101b, 111a, 11
1b, 121a, 121b, 131a, 131b, 14
1a, 141b, 151a, 151b, 161a, 16
1b, 171a, 171b, 181a, 181b Pilot pressure signals 92a, 92b, 102a, 102b, 112a, 11
2b, 122a, 122b, 132a, 132b, 14
2a, 142b Pressure sensor 93, 103 Pressure sensor

Claims (4)

[Claims] 1. A first and a second hydraulic pump, a group of hydraulic actuators driven by hydraulic oil discharged from the first and the second hydraulic pumps, and the first and the second hydraulic pumps A closed-center type directional control valve group for controlling the flow of hydraulic oil supplied to the hydraulic actuator group from the first hydraulic pump, and the highest load pressure among the load pressures of the actuator groups for supplying hydraulic oil to the first hydraulic pump. Means for detecting a certain first maximum load pressure, means for detecting a second maximum load pressure that is the highest load pressure among the load pressures of the actuator groups that supply the hydraulic oil by the second hydraulic pump, Provided in each of the direction control valve group,
A hydraulic drive device comprising: a pressure control valve group that operates at the first and second maximum load pressures and enables a flow rate distribution to an actuator group; wherein the first and second hydraulic pumps and each direction control valve are provided. A first position for supplying only pressure oil from the first hydraulic pump, a second position for supplying only pressure oil from the second hydraulic pump, the first and second positions. One of the 3rd positions where the hydraulic oil from the hydraulic pump is joined and supplied
An auxiliary valve group that can be switched off, and the first maximum load pressure is led to a pressure control valve group related to an actuator group to which pressure oil from a first hydraulic pump is supplied, and the second maximum load pressure is set. A signal switching valve group switchable in conjunction with the auxiliary valve group so as to guide the pressure control valve group to an actuator group to which pressure oil is supplied from the second hydraulic pump; And a switching control means for determining a position pattern and controlling on / off switching of the auxiliary valve group so as to obtain this pattern. 2. The hydraulic drive device according to claim 1, wherein the switching control means includes: a command means group for outputting a command signal for operating the directional control valve group; and a command signal from the command means group. Means for determining a switching position pattern of the auxiliary valve group in accordance with an operation state of the actuator group. 3. The hydraulic drive system according to claim 1, wherein said switching control means outputs a command signal group for operating a command signal for operating said directional control valve group and a setting signal for a work mode of said actuator group. Setting means for inputting a command signal from the commanding means group and a setting signal from the setting means, and determining a switching position pattern of the auxiliary valve group in accordance with an operation state of the actuator group. A hydraulic drive device characterized by the following. 4. The hydraulic drive device according to claim 1, wherein said switching control means outputs a command signal group for operating a command signal for operating said directional control valve group, and outputs a work mode setting signal for said actuator group. Setting means, a pressure sensor group for detecting a load pressure of the actuator group, a command signal from the commanding means group, a setting signal from the setting means, and a detection signal from the pressure sensor group to input the actuator group. Means for determining a pattern of the switching position of the auxiliary valve group in accordance with the operating condition of the hydraulic drive device.