JPH1061608A - Hydraulic driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly distribute a discharge flow rate from the hydraulic pump of a merge supplying side to the discharge circuit of the merge supplying side and the discharge circuit of a merged side at the time of merging, to properly supply hydraulic oil to the hydraulic actuator of the merge supplying side and to also supply the merged hydraulic oil to the discharge circuit of the merged side. SOLUTION: A merging circuit 100 is provided between the discharge circuit 11 of a hydraulic pump 1 and the discharge circuit 12 of a hydraulic pump 6, the merging circuit 100 includes tow merging lines 13a and 13b for connecting the discharge circuits 11 and 12, two merging/separating switch valves 14a and 14b respectively provided in the merging lines 13a and 13b and two pressure control valves 47 and 48 respectively installed in the merging lines 13a and 1b, the pressure control valve 47 controls the pressure of the exist side of the merging/separating switch valve 14a to be equal to that of a sensing line 28 and the pressure control valve 48 controls the pressure of the exit side of the merging/separating switch valve 14b to be equal to that of a sensing line 27.

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, and more particularly to a hydraulic drive device capable of supplying hydraulic oil to a plurality of hydraulic actuators at the junction of two pumps by connecting the discharge circuits of two hydraulic pumps by a joining circuit. About.

[0002]

2. Description of the Related Art There have been proposed various prior arts of a joining / dividing system of two hydraulic pumps in a hydraulic drive system, and one example thereof is described in Japanese Patent Application Laid-Open No. Hei 1-3316502. FIG. 10 shows the prior art, in which a variable displacement hydraulic pump 1 driven by a power source such as an engine, hydraulic actuator groups 2 and 3 driven by pressure oil discharged from the hydraulic pump 1, and hydraulic pressure Direction switching units 301a and 301b for switching the direction in which hydraulic oil is sent from the hydraulic pump 1 to the hydraulic actuator groups 2 and 3 between the pump 1 and the speed for setting the speeds and driving directions of the hydraulic actuator groups 2 and 3 Setting device 307
a, 307b, and a variable aperture unit 303a that changes the opening area according to the set amount of the speed setting units 307a, 307b.
303b, and pressure control valves 43a and 43b for controlling the differential pressure across the variable throttle portions 303a and 303b to a predetermined value regardless of the magnitude of the load pressure of the hydraulic actuator groups 2 and 3 are provided. Also, as described above, the hydraulic pump 6
Between the hydraulic pumps 6 and the hydraulic actuator groups 7 and 8 driven by the hydraulic oil discharged from the hydraulic pump 6, the switching direction of the hydraulic oil sent from the hydraulic pump 6 to the hydraulic actuator groups 7 and 8 is switched. Direction switching unit 302
a, 302b and speed setting devices 308a, 308b for setting the speed and driving direction of the hydraulic actuator groups 7, 8
And variable aperture units 304a and 304b that change the opening area according to the set amounts of the speed setting units 308a and 308b;
Pressure control valves 46a and 46b are provided for controlling the differential pressure across the variable throttle portions 304a and 304b to a predetermined value regardless of the magnitude of the load pressure of the hydraulic actuator groups 7 and 8. Further, a sensing line 27 for detecting the maximum load pressure of the hydraulic actuator groups 2 and 3, a sensing line 28 for detecting the maximum load pressure of the hydraulic actuator groups 7 and 8, a branch from the discharge circuit 11 and a tank via a throttle 84. And a bypass line 88 connected to the
8, a bypass valve 110 that switches to the opening direction when the difference between the discharge pressure of the hydraulic pump 1 and the pressure detected by the sensing line 27 is equal to or greater than a predetermined value.
A pilot line 86 that guides the pressure on the outlet side of the hydraulic pump 1 (hereinafter referred to as the negative control pressure on the hydraulic pump 1 side) to the hydraulic pump 1
A bypass line 89 branched from the discharge circuit 12 and connected to the tank via the throttle 85, and a difference between the discharge pressure of the hydraulic pump 6 and the pressure detected by the sensing line 28 is equal to or more than a predetermined value. And a pilot line 87 that guides the pressure on the outlet side of the bypass valve 111 (hereinafter referred to as the negative control pressure on the hydraulic pump 6 side) to the hydraulic pump 6.

Here, as the difference between the discharge pressure of the hydraulic pump 1 and the pressure detected at the sensing line 27 becomes lower than a predetermined value, the bypass valve 110 operates in the closing direction. Similarly, as the difference between the discharge pressure of the hydraulic pump 6 and the pressure detected at the sensing line 28 becomes lower than a predetermined value,
Since the bypass valve 111 acts in the closing direction, the negative control pressure on the hydraulic pump 6 side decreases.

The hydraulic pump 1 is of a variable displacement type, and is provided with a servo mechanism 29 for controlling the discharge flow rate. The servo mechanism 29 presets a negative control pressure on the hydraulic pump 1 side guided by a pilot line 86. Negative flow control is performed to control the tilting of the hydraulic pump 1 so that the pump discharge flow rate is reduced when the value exceeds the set value, and the pump discharge flow rate is increased when the value becomes lower than the set value. Similarly, the hydraulic pump 6 is provided with a servo mechanism 42 as a discharge amount control means.
The servo mechanism 42 reduces the pump discharge flow rate when the negative control pressure on the hydraulic pump 6 side guided by the pilot line 87 is equal to or higher than a preset value, and increases the pump discharge flow rate when the negative control pressure is lower than the preset value. The negative flow rate control for controlling the tilt of the hydraulic pump 6 is performed.

[0005] Between the discharge circuit 11 of the hydraulic pump 1 and the discharge circuit 12 of the hydraulic pump 6, a merge / divide switch valve 140a,
The connection / disconnection switching valve 140a is connected via a merging line 13 via a 140b, and a diverting position for shutting off between the discharge circuit 11 and the discharge circuit 12;
The discharge circuit 11 and the discharge circuit 12 communicate with each other via a check valve 51 and a variable throttle 150a that allow only the flow of the pressure oil toward the side, and the hydraulic pump 1 side is connected to the merge / divide flow switching valve 140a. Merging line 13 and sensing line 2
4 port 2 that can be switched to the merging position to connect 8
A position switching valve, and a joining / diverting switching valve 140b is also a branching position for shutting off between the discharge circuit 11 and the discharge circuit 12, and a check valve allowing only the flow of the hydraulic oil from the hydraulic pump 1 side to the hydraulic pump 6 side. The discharge circuit 11 and the discharge circuit 12 are communicated with each other via the variable aperture 52 and the variable throttle 150b.
This is a four-port two-position switching valve that can be switched to a merging position where the merging line 13 on the hydraulic pump 6 side and the sensing line 27 are connected to the diversion switching valve 140b.

[0006] The merge / shunt switch valve 140a is connected to the hydraulic pump 1
The valve is operated by the balance between the negative control pressure on the side and the spring 78. The spring 78 has a shortage of the discharge flow rate with respect to the required flow rate of the hydraulic actuator groups 2 and 3 corresponding to the hydraulic pump 1, and can supply the required flow rate. When the hydraulic pump 1 is in a non-existing state, that is, when the hydraulic pump 1 is in a saturation state, the setting is made such that the merge / shunt switch valve 140a is switched to the merge position. Also, the merge / shunt switch valve 140b is a valve that operates according to the balance between the negative control pressure on the hydraulic pump 6 side and the spring 79. The spring 79 adjusts the required flow rate of the hydraulic actuator groups 7, 8 corresponding to the hydraulic pump 6. On the other hand, when the discharge flow rate is insufficient and the required flow rate cannot be supplied, that is, when the hydraulic pump 6 is in the saturation state, the merge / divide switch valve 140b is switched to the merge position.

That is, when the negative control pressure on the hydraulic pump 1 side becomes lower than the set value of the spring 78, the merge / divide switch valve 140a switches to the merge position, and the merge / divide switch valve 140b adjusts the negative control pressure on the hydraulic pump 6 side. When it becomes lower than the set value of 79, it switches to the merging position.

The variable throttle 150a is provided with the hydraulic pump 1
The opening area of the hydraulic actuators 2 and 3 is adjusted so that an insufficient flow rate with respect to the required flow rate is supplied from the hydraulic pump 6. That is, the hydraulic pump 1 is in the saturation state, and the hydraulic actuator groups 2, 3
As the required flow rate increases and the negative control pressure on the hydraulic pump 1 side decreases, the opening area of the variable throttle 150a increases, and the insufficient flow rate is supplied from the hydraulic pump 6 to the discharge circuit 11 on the hydraulic pump 1 side.

The opening area of the variable throttle 150b is also adjusted so that an insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 7 and 8 corresponding to the hydraulic pump 6 is supplied from the hydraulic pump 1. That is, as the hydraulic pump 6 is in the saturation state, the required flow rate of the hydraulic actuator groups 7 and 8 increases, and the negative control pressure on the hydraulic pump 6 side decreases, the opening area of the variable throttle 150b increases, and the hydraulic pump 1 reduces the insufficient flow rate. To the discharge circuit 12 on the hydraulic pump 6 side.

Here, for example, when there is a margin for the required flow rate of the hydraulic actuator groups 2 and 3 corresponding to the hydraulic pump 1, the merge / divide flow switching valve 140a is located at the branch position.
The hydraulic pump 1 side is a circuit independent of the hydraulic pump 6 side.

On the other hand, for example, when the required flow rate is insufficient for the required flow rate of the hydraulic actuator groups 2 and 3 corresponding to the hydraulic pump 1, and the required flow rate cannot be supplied, that is, the hydraulic pump 1 is in the saturation state. At this time, the joining / diverting switching valve 140a is switched to the joining position, and the pressure oil can be supplied from the discharge circuit 12 of the hydraulic pump 6 to the discharge circuit 11 of the hydraulic pump 1 via the variable throttle 150a. Is also supplied to the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side, and the required flow rate can be secured. At the same time, since the merging line 13 on the hydraulic pump 1 side and the sensing line 28 are connected, the higher of the discharge pressure of the hydraulic pump 1 and the maximum load pressure of the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side becomes higher. The pump discharge flow rate of the hydraulic pump 6 is controlled by acting on the bypass valve 111.

[0012]

However, the above-mentioned conventional merging / splitting method has the following problems.

For example, when the hydraulic pump 1 is in a saturation state, the merge / shunt switch valve 140a is switched to the merge position, and the hydraulic oil is transferred from the discharge circuit 12 on the hydraulic pump 6 side to the discharge circuit 11 on the hydraulic pump 1 side. Supply is possible, and the supply flow rate depends on the negative control pressure on the hydraulic pump 1 side, that is, according to the required flow rate of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side, 3 is adjusted by the opening area of the variable throttle 150a so that the insufficient flow rate can be supplied.

However, even if the opening area of the variable throttle 150a is constant, the lower the pressure of the discharge pressure 11 on the hydraulic pump 1 side from the pressure of the discharge circuit 12 on the hydraulic pump 6 side, the more the hydraulic pump 6 is supplied to the discharge circuit 11 on the hydraulic pump 1 side, and the hydraulic oil supplied from the hydraulic pump 6 to the hydraulic actuator groups 7 and 8 is supplied to the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side. Since the remaining flow rate that cannot pass through the variable throttle 150a is supplied until the required flow rate is satisfied, the circuit configuration is led by the discharge circuit 11 on the hydraulic pump 1 side which is the merging side, and the merging and supply is performed by merging. The required flow rate of the hydraulic oil is not supplied to the hydraulic actuator groups 7 and 8 on the side.

Even if the opening area of the variable throttle 150a is constant as described above, the change in the pressure difference between the discharge circuit 11 on the hydraulic pump 1 side and the discharge pressure 12 on the hydraulic pump 6 causes Since the flow rate of the pressure oil supplied from the hydraulic pump 6 to the discharge circuit 11 on the hydraulic pump 1 side changes, the speed control and the position control of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side which is the merging side are performed. In such a case, it is not possible to grasp an accurate supply flow rate to the hydraulic actuator groups 2 and 3.

An object of the present invention is to provide a hydraulic drive device capable of joining the discharge flow rates of two hydraulic pumps and supplying the combined flow rates to a plurality of hydraulic actuators. Hydraulic drive that can appropriately distribute pressure oil to the circuit and the discharge circuit on the merging side to supply hydraulic oil appropriately to the hydraulic actuator on the merging supply side, and also merge and supply pressure oil to the discharging circuit on the merging side It is to provide a device.

[0017]

[Means for Solving the Problems]

(1) In order to achieve the above object, the present invention provides first and second variable displacement hydraulic pumps and a first and a second hydraulic pumps, each of which is driven by hydraulic oil discharged from the first and second hydraulic pumps.
And the second hydraulic actuator group, and the first and second hydraulic actuators.
First and second directional control valve groups for controlling the flow of pressure oil supplied from the hydraulic pump to the first and second hydraulic actuator groups, and detecting the maximum load pressure of the first hydraulic actuator group A first sensing line, a second sensing line for detecting a maximum load pressure of the second hydraulic actuator group, and a pressure on an outlet side of the first direction switching valve group for the first sensing line. A first pressure control valve that controls the same pressure as a pressure; and a second pressure control valve that controls the pressure on the outlet side of the second direction switching valve group to be the same as the pressure of the second sensing line. A hydraulic drive device for controlling a discharge flow rate of the first and second hydraulic pumps according to a required flow rate of the first and second hydraulic actuator groups, wherein a discharge circuit of the first hydraulic pump and a second Hydraulic pressure A merging line that connects the discharge circuit of the pump and a merging / distributing switching valve that is arranged in the merging line and that can be switched between a merging position where both the discharging circuits are shut off and a merging position where the two discharging circuits communicate with each other via a throttle. And a third pressure control valve for controlling the pressure on the outlet side of the merge / shunt switch valve to be the same as the pressure of the sensing line corresponding to the other hydraulic pump when switched to the merge position. And when one of the first and second hydraulic pumps cannot supply the required flow rate of the hydraulic actuator group on the hydraulic pump side,
A diverting / diverting switching control means for switching the diverting switching valve to the merging position is provided.

In the present invention constructed as described above, the third pressure control valve for controlling the pressure on the outlet side of the merge / shunt switch valve to be equal to the pressure on the sensing line on the merge supply side is provided in the merge line. Therefore, even if the pressure difference between the discharge circuit on the merging side and the discharge circuit on the merging supply side changes, the pressure on the outlet side of the merging / shunting switching valve will remain at the outlet side of the direction switching valve group on the merging supply side. The pressure difference is always the same as the pressure, and the differential pressure across the diverting / diverting selector valve is always the same as the differential pressure across the directional switching valve group on the merging supply side. The hydraulic actuator group on the merging supply side and the discharge circuit on the merging side are appropriately distributed according to the opening area of the directional switching valve group on the side and the opening area of the merging / shunting switching valve. With the proper supply of pressure oil to the actuator, Can be supplied also joins the pressure oil to discharge circuit of the confluence side.

Further, since the discharge circuits of the hydraulic pumps 1 and 6 are communicated via the throttle at the merge position of the merge / divide flow switching valve, the independence of the discharge flow control of the first and second hydraulic pumps is maintained. When the first and second hydraulic pumps are controlled by horsepower, the pump discharge flow rate on the surplus side can be used to the maximum.

(2) In the above (1), preferably,
The merge / shunt switch valve is a valve that changes a stroke position according to a required flow rate of the hydraulic actuator group,
The diaphragm is a variable diaphragm that increases the opening area according to the stroke position.

With the above configuration, the flow rate of the pressure oil supplied from the hydraulic pump on the merging supply side to the discharge circuit on the merging side varies depending on the degree of saturation of the hydraulic pump on the merging side. Thus, a flow rate corresponding to the insufficient flow rate of the hydraulic actuator group on the merging side can be supplied.

(3) In the above (1) or (2), preferably, the discharge flow rate of the first hydraulic pump is controlled so that the pump discharge pressure is higher than the pressure of the first sensing line. A second discharge amount control means;
A second discharge amount control means for controlling a discharge flow rate of the second hydraulic pump so that a pump discharge pressure is higher than a pressure of the sensing line. When the pressure difference between the discharge pressure of the hydraulic pump and the pressure of the sensing line on the one hydraulic pump side becomes smaller than a predetermined value, the merge / divide switch valve is switched to the merge position.

(4) In the above (1) or (2), preferably, the first and second bypass lines branched from the discharge circuits of the first and second hydraulic pumps and connected to the tank, respectively. A first variable throttle provided in the first bypass line, the opening of which is reduced when the operation amount of the first direction switching valve group increases, and a first variable throttle provided in the second bypass line, A second variable throttle for reducing the opening area when the operation amount of the second directional control valve group is increased, and a second variable throttle provided at an outlet side of each of the first and second variable throttles, and a pressure is generated at each of the outlet sides. First and second throttles to be provided and provided between the first variable throttle and the first throttle, and the pressure on the outlet side of the first variable throttle is made equal to the pressure of the first sensing line. 4th pressure to control the same A fifth control valve is provided between the second variable throttle and the second throttle, and controls the pressure on the outlet side of the second variable throttle to be the same as the pressure on the second sensing line. A pressure control valve, a first discharge amount control means for detecting a pressure generated in the first throttle, and controlling a discharge flow rate of the first hydraulic pump in accordance with the pressure;
A second discharge amount control means for detecting a pressure generated in the second throttle and controlling a discharge flow rate of the second hydraulic pump in accordance with the pressure; When the pressure generated by the throttle provided in the bypass line on the one hydraulic pump side becomes lower than a predetermined value, the merge / divide switch valve is switched to the merge position.

(5) In the above (3) or (4), preferably, the merge / divide switch valve is connected to the discharge circuit of the one hydraulic pump with respect to the merge / divide switch valve at the merge position. The other hydraulic pump side is connected to the sensing line.

With the above arrangement, even when the discharge pressure of the hydraulic pump on the merging supply side is lower than the discharge pressure of the hydraulic pump on the merging side, the sensing line on the merging supply side is stepped up to supply the merging supply. The discharge pressure of the hydraulic pump on the side can be made higher than the discharge pressure of the hydraulic pump on the side to be joined, and hydraulic oil can be supplied from the hydraulic pump on the side of the merged supply to the discharge circuit on the side of the merged side.

(6) In the above (1) or (2), preferably, the first and second operation lever groups for operating the first and second directional control valve groups, respectively, and the first operation A first discharge amount control means for detecting a command signal from a lever group and controlling a discharge flow rate of the first hydraulic pump according to the command signal, and detecting a command signal from the second operation lever group And a second discharge amount control means for controlling a discharge flow rate of the second hydraulic pump in accordance with the command signal, wherein the merge / divide flow switching control means comprises an operating lever on the one hydraulic pump side. The required flow rate of the hydraulic actuator group on the hydraulic pump side is determined by the group command signal, and when the determined required flow rate is greater than the discharge flow rate of the one hydraulic pump, the merge / divide switch valve is switched to the merge position. thing To.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention is shown in FIG.
This will be described below.

In FIG. 1, a hydraulic drive device according to a first embodiment of the present invention includes a hydraulic pump 1 driven by a prime mover 38 and hydraulic actuators 2 and 3 driven by hydraulic oil discharged from the hydraulic pump 1. (Hereinafter referred to as hydraulic actuator groups 2 and 3), and a hydraulic pump 1 and hydraulic actuator groups 2 and 3
Directional control valve group (hereinafter, directional control valve group) including directional control valves 4 and 5 provided between the hydraulic pumps 1 to control the flow rate of the hydraulic oil sent from the hydraulic pump 1 to the hydraulic actuator groups 2 and 3 and switch the feed direction of the hydraulic oil. Switching valve groups 4 and 5), a sensing line 27 including check valves 27a and 27b for detecting the highest load pressure (hereinafter referred to as a maximum load pressure) of the hydraulic actuator groups 2 and 3, and a pressure of the sensing line 27. Acts, and a pressure control valve group (hereinafter, referred to as a pressure control valve group) including pressure control valves 43 and 44 for controlling the outlet pressure of the meter-in variable throttle incorporated in each of the direction switching valve groups 2 and 3 to be equal to the pressure of the sensing line 27. Pressure control valve groups 43 and 44). Similarly, the prime mover 38
Hydraulic pump 6 driven by
A hydraulic actuator group including hydraulic actuators 7 and 8 driven by pressure oil discharged from the hydraulic pumps (hereinafter referred to as hydraulic actuator groups 7 and 8), and a hydraulic pump provided between the hydraulic pump 6 and the hydraulic actuator groups 7 and 8; 6 directional control valves 9, 1 for controlling the flow rate of the pressure oil sent to the hydraulic actuator groups 7, 8 and for switching the feed direction of the pressure oil.
A directional switching valve group including 0 (hereinafter referred to as directional switching valve groups 9 and 10) and check valves 28a and 28b for detecting the highest load pressure (hereinafter referred to as maximum load pressure) of the hydraulic actuator groups 7 and 8 are included. The pressure of the sensing line 28 and the pressure of the sensing line 28 act to control the outlet pressure of the meter-in variable throttle incorporated in each of the direction switching valve groups 9 and 10 to be the same as the pressure of the sensing line 28. , 46 (hereinafter, referred to as a pressure control valve group)
Pressure control valve groups 45 and 46).

The hydraulic pump 1 is of a variable displacement type, and is provided with an LS control valve 20 and a servo mechanism 29 as discharge amount control means. The LS control valve 20 is connected to a pilot line 18 and a sensing line 27 branching from the discharge circuit 11 of the hydraulic pump 1, and the servo mechanism 2 controls the discharge pressure of the hydraulic pump 1 to be higher than the maximum load pressure by a predetermined value.
9 controls the tilting of the hydraulic pump 1.

The hydraulic pump 6 is also of a variable displacement type, and is provided with an LS control valve 24 and a servo mechanism 42 as its discharge amount control means. The LS control valve 24 is connected to a pilot line 23 and a sensing line 28 branching from the discharge circuit 12 of the hydraulic pump 6, and controls the servo mechanism 4 so that the discharge pressure of the hydraulic pump 6 becomes higher than the maximum load pressure by a predetermined value.
2 controls the tilting of the hydraulic pump 6.

That is, the discharge flow rate of the hydraulic pumps 1 and 6 is controlled by load sensing control.

A merge circuit 100 is provided between the discharge circuit 11 of the hydraulic pump 1 and the discharge circuit 12 of the hydraulic pump 6. The merging circuit 100 includes two merging lines 13a and 13b connecting the two discharge circuits 11 and 12, and two merging / diverting switching valves 14a and 14b disposed on the two merging lines 13a and 13b, respectively. And two pressure control valves 47 and 48 arranged on the two merging lines 13a and 13b, respectively. Combination / diversion switching valve 14
a is a branch position where the junction line 13a is interrupted, and
a two-port two-position switching valve that can be switched to a merging position where the merging line 13a is communicated through the a. A merging / shunting switching valve 14b is also connected to the merging line via the throttle 50b. 13b is a two-port two-position switching valve that can be switched to a merging position where the valve 13b communicates. The pressure control valve 47 is provided on the merging line 13a on the hydraulic pump 1 side (hereinafter, simply referred to as the merging line 13a on the hydraulic pump 1 side) with respect to the merging / shunting switching valve 14a, and the pressure of the sensing line 28 is reduced. The pressure of the merging line 13a on the hydraulic pump 1 side
8 and the pressure control valve 48 is connected to the merging line 13 on the hydraulic pump 6 side with respect to the merging / shunting switching valve 14b.
b (hereinafter simply referred to as the merging line 13b on the hydraulic pump 6 side), the pressure of the sensing line 27 acts, and the pressure of the merging line 13b on the hydraulic pump 6 side is controlled to be the same as the pressure of the sensing line 27. . The pressure control valve 47 includes a check mechanism that allows only the flow of the pressure oil from the hydraulic pump 6 to the hydraulic pump 1.
Has a check mechanism that allows only the flow of the pressure oil from the hydraulic pump 1 to the hydraulic pump 6.

The merge / shunt switch valve 14a is of a hydraulic pilot switching type, and operates by the balance between the spring 76 and the differential pressure between the discharge pressure of the hydraulic pump 1 and the maximum load pressure detected by the sensing line 27. When the differential pressure between the discharge pressure and the maximum load pressure is maintained at the set value of the spring 76 (load sensing set differential pressure), the flow is at the shunt position, and when the differential pressure becomes smaller than the set value of the spring 76, the merging occurs. Switch to position. Also, the merge / shunt switch valve 14b is of a hydraulic pilot switching type, and operates by the balance between the spring 77 and the differential pressure between the discharge pressure of the hydraulic pump 6 and the maximum load pressure detected by the sensing line 28, and the pump discharge is performed. The pressure difference between the pressure and the maximum load pressure is the spring 77
When the differential pressure is smaller than the set value of the spring 77, the switch is made to the merging position. That is, the discharge circuits 11 or 12 and the sensing lines 27 and 28 are connected to the drive units at both ends of the merge / divide flow switching valves 14a and 14b.
The pilot line connected to the above constitutes a joining / shunt switching control means as the switching means.

The switching control of the merge / shunt switch valves 14a and 14b will be described below.

When the differential pressure between the discharge pressure of the hydraulic pump 1 and the maximum load pressure of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side becomes lower than the load sensing set differential pressure, the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side. The hydraulic pump 1 is determined to be in a saturation state in which the discharge flow rate is insufficient to supply the required flow rate with respect to the required flow rate, and the merge / shunt switch valve 14a is switched to the merge position to change the discharge pressure of the hydraulic pump 6. Is higher than the discharge pressure of the hydraulic pump 1, the pressure oil from the hydraulic pump 6 is supplied to the discharge circuit 11 on the hydraulic pump 1 side. At this time, the hydraulic pumps 1, 6
Since the discharge circuits 11 and 12 communicate with each other through the throttle 50a, the independence of the load sensing control by the LS control valves 20 and 24 of the hydraulic pumps 1 and 6 is maintained. Further, the pressure on the outlet side of the merge / shunt switch valve 14a is controlled to be the same as the pressure on the sensing line 28 by the pressure control valve 47, and the pressure control valves 45 and 46 control the outlet side of the directional switch valve groups 9 and 10 on the outlet side. Since the pressure is also controlled to be equal to the pressure of the sensing line 28, the differential pressure across the diverting / diverting switching valve 14a is always the same as the differential pressure across the directional switching valve groups 9 and 10, and the discharge flow rate from the hydraulic pump 6 The opening area of the directional control valve groups 9 and 10 and the opening of the restrictor 50a of the merge / divide valve 14a are changed even if the pressure difference between the discharge circuit 12 of the hydraulic pump 6 and the discharge circuit 11 of the hydraulic pump 1 changes. The hydraulic fluid is distributed to the hydraulic actuator groups 7, 8 on the hydraulic pump 6 side, which is the merging supply side, and the discharge circuit 11 on the hydraulic pump 1 side, which is the merging side, according to the area. Is properly supplied Also supplied joins the pressure oil to discharge circuit 11 of the hydraulic pump 1 side.

When the discharge pressure of the hydraulic pump 6 is lower than the discharge pressure of the hydraulic pump 1, the pressure oil from the hydraulic pump 6 is not supplied to the discharge circuit 11 on the hydraulic pump 1 side. The check mechanism prevents the pressure oil from the hydraulic pump 1 from flowing back into the discharge circuit 12 on the hydraulic pump 6 side.

When the differential pressure between the discharge pressure of the hydraulic pump 1 and the maximum load pressure of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side is maintained at the load sensing set differential pressure, the merge / divide switch valve 14a is turned on. Keep in shunt position.

Similarly, when the pressure difference between the discharge pressure of the hydraulic pump 6 and the maximum load pressure of the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side becomes lower than the load sensing set differential pressure, the hydraulic actuator on the hydraulic pump 6 side A state where the discharge flow rate is insufficient for the required flow rate of the groups 7 and 8 and the required flow rate cannot be supplied, that is, the hydraulic pump 6 is determined to be in the saturation state, and the merge / divide switch valve 14b is switched to the merge position to change the hydraulic pump. When the discharge pressure is higher than the discharge pressure of the hydraulic pump 6, the hydraulic oil from the hydraulic pump 1 is supplied to the discharge circuit 12 on the hydraulic pump 6 side. At this time, since the discharge circuits 11 and 12 of the hydraulic pumps 1 and 6 communicate with each other through the throttle 50b, the LS control valves 20 and 2 of the hydraulic pumps 1 and 6 are connected.
4 keeps the load sensing control independent. Further, the pressure on the outlet side of the merge / shunt switch valve 14b is controlled to be the same as the pressure on the sensing line 27 by the pressure control valve 48. Since the pressure is also controlled to be the same as the pressure of the sensing line 27, the differential pressure across the diverting / diverting switching valve 14b is always the same as the differential pressure across the directional switching valve groups 4 and 5,
Even when the pressure difference between the discharge circuit 11 of the hydraulic pump 1 and the discharge circuit 12 on the hydraulic pump 6 side changes, the discharge flow rate from the hydraulic pump 1 changes with the opening areas of the directional control valve groups 4 and 5 and the merge / divide flow. The hydraulic actuators are distributed to the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side, which is the merging supply side, and the discharge circuit 12 on the hydraulic pump 6 side, which is the merging side, according to the opening area of the throttle 50b of the valve 14b. The pressure oil is appropriately supplied to the groups 2 and 3, and the pressure oil is also supplied to the discharge circuit 12 on the hydraulic pump 6 side by merging.

When the discharge pressure of the hydraulic pump 1 is lower than the discharge pressure of the hydraulic pump 6, the pressure oil from the hydraulic pump 1 is not supplied to the discharge circuit 12 on the hydraulic pump 6 side. The check mechanism prevents the pressure oil from the hydraulic pump 6 from flowing back to the discharge circuit 11 on the hydraulic pump 1 side.

When the differential pressure between the discharge pressure of the hydraulic pump 6 and the maximum load pressure of the corresponding hydraulic actuator group 7, 8 is maintained at the load sensing set differential pressure, the junction / division switching valve 14b is set to the division position. keep.

As described above, according to this embodiment, since the pressure control valves 47 and 48 are provided in the merging lines 13a and 13b, respectively, the discharge circuit of the hydraulic pump on the merging side and the hydraulic pump on the merging supply side are provided. Even if the pressure difference with the discharge circuit changes, the pressure on the outlet side of the diverting / diverting switching valve is always controlled to be the same as the pressure on the outlet side of the directional switching valve group on the merging supply side. The front-rear pressure difference is always the same as the front-rear pressure difference of the directional switching valve group on the merging supply side, and the discharge flow rate from the hydraulic pump on the merging supply side depends on the opening area of the directional switching valve group on the merging supply side and merging / diverting. The hydraulic fluid is appropriately distributed to the hydraulic actuator group on the merging supply side and the discharge circuit on the merging side according to the opening area of the valve. As a result, the hydraulic oil can be appropriately supplied to the hydraulic actuator group on the merging supply side, and To the discharge circuit on the side It is possible to feed.

Further, since the discharge circuits 11 and 12 of the hydraulic pumps 1 and 6 are communicated through the throttles 50a and 50b respectively at the merging positions of the merge / divide flow switching valves 14a and 14b, the LS control valves of the hydraulic pumps 1 and 6 are connected. The independence of the load sensing control by the control units 20 and 24 is maintained, and the pump discharge flow rate on the surplus side when the hydraulic pumps 1 and 6 are controlled by horsepower can be used to the maximum.

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

In FIG. 2, the discharge circuit 1 of the hydraulic pump 1
A merging circuit 100 </ b> A is provided between the hydraulic circuit 1 and the discharge circuit 12 of the hydraulic pump 6 and between the sensing line 27 and the sensing line 28. The merging circuit 100A is shown in FIG.
In the merging circuit 100 of the first embodiment shown in FIG.
A and 14B are respectively provided, branch from the sensing line 28, and a merging line 74a connected to the merging line 13a on the outlet side of the pressure control valve 47, and a merging line 74a branching from the sensing line 27, and merging line 13a and the outlet of the pressure control valve 48. Line 74b, which is connected on the side, and is provided on the merging line 74a, and is connected to the sensing line 28a from the merging line 13a.
And a check valve 54 provided on the merging line 74b and allowing only the flow of the pressurized oil from the merging line 13b to the sensing line 27.
Are further provided.

The merge / shunt switch valve 14A is connected to the merge line 13
a and 74a, and a variable throttle 150
This is a four-port two-position switching valve that can be switched to a merging position where the merging line 13a is communicated via a and the merging line 74a is communicated through the a.

The diverging / diverting switching valve 14B is also connected to the convergence line 13
b and 74b, and a variable flow restrictor 150
This is a four-port two-position switching valve that can be switched to a merging position where the merging line 13b communicates with the merging line 13b and the merging line 74b communicates with the merging line 13b.

The merge / divide switch valve 14A is of a hydraulic pilot switching type, and has a load sensing difference between the discharge pressure PS1 of the hydraulic pump 1 and the maximum load pressure PLm1 of the actuator group on the hydraulic pump 1 side for one side. Pressure ΔP1
Through the discharge circuit 11 and the sensing line 27, respectively, and discharge pressure PS2 of the hydraulic pump 6 to the opposite side.
And the maximum load pressure P of the actuator group on the hydraulic pump 6 side
The load sensing differential pressure ΔP2 with Lm2 is led through the discharge circuit 12 and the sensing line 28, respectively, and the load sensing differential pressure ΔP1 becomes the load sensing differential pressure ΔP2.
In the above case, it is at the branch position and the load sensing differential pressure Δ
When P1 becomes smaller than the load sensing differential pressure ΔP2, it switches to the merging position. The merge / divide flow switching valve 14B is also of a hydraulic pilot switching type, and the load sensing differential pressure ΔP1 between the discharge pressure PS1 of the hydraulic pump 1 and the maximum load pressure PLm1 of the actuator group on the hydraulic pump 1 side for one side.
Through the discharge circuit 11 and the sensing line 27, respectively, and discharge pressure PS2 of the hydraulic pump 6 to the opposite side.
And the maximum load pressure P of the actuator group on the hydraulic pump 6 side
The load sensing differential pressure ΔP2 with Lm2 is led through the discharge circuit 12 and the sensing line 28, respectively, and the load sensing differential pressure ΔP2 becomes the load sensing differential pressure ΔP1.
In the above case, it is at the branch position and the load sensing differential pressure Δ
When P2 becomes smaller than the load sensing differential pressure ΔP1, it switches to the merging position. That is, when ΔP1 <ΔP2, the merge / divide switch valve 14A is switched to the merge position and the merge / divide switch valve 14B is maintained at the branch position. When ΔP1> ΔP2, the merge / divide switch valve 14A is switched to the merge position. Is switched to the merging position, and when .DELTA.P1 = .DELTA.P2, both the merging / diverting switching valves 14A and 14B are maintained at the diverging position.

Therefore, in the present embodiment, similarly to the first embodiment, a pilot line connecting the drive units at both ends of the merge / shunt switch valves 14A and 14B to the associated discharge circuit 11 or 12 and the sensing lines 27 and 28 is provided. A merge / shunt switching control means as the switching means is constituted.

The opening area of the variable throttle 150a increases as the load sensing differential pressure ΔP1 becomes smaller than the load sensing differential pressure ΔP2, that is, as the required flow rate of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side increases. , Hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side
The variable throttle 150b is set so that the load sensing differential pressure ΔP2 becomes smaller than the load sensing differential pressure ΔP1, that is, the hydraulic actuator group 7, 7 on the hydraulic pump 6 side.
As the required flow rate of the hydraulic pump 8 increases, the opening area thereof is increased so that the insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side is set. Therefore, the merge / divide flow switching valve 14A changes the stroke position in accordance with the required flow rate of the hydraulic actuator groups 2 and 3, and increases the opening area of the built-in variable throttle 150a in accordance with the stroke position. Switching valve 1
4B also changes the stroke position according to the required flow rates of the hydraulic actuator groups 7 and 8, and increases the opening area of the built-in variable throttle 150b according to the stroke position.

In this embodiment configured as described above, when the hydraulic pump 1 enters the saturation state and cannot supply the required flow rates of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side, the load sensing difference is reduced. Pressure Δ
P1 decreases, and the merge / shunt switch valve 14A is set to the variable throttle 150
a to the merging position where the merging line 13a and the merging line 74a communicate with each other via the
50a is a group of hydraulic actuators 2, 3 on the hydraulic pump 1 side according to the degree of reduction of the load sensing differential pressure ΔP1.
The opening area is set so that the insufficient flow rate with respect to the required flow rate passes.

Here, when the discharge pressure of the hydraulic pump 6 is higher than the discharge pressure of the hydraulic pump 1, the merging line 13a and the sensing line 28 are shut off by the check valve 53, and the pressure of the sensing line 28 is reduced by the hydraulic actuator group 7, 8, the discharge pressure of the hydraulic pump 6 remains the same as before the merge / divide switch valve 14A switches to the merge position. Then, the pressure is controlled by the pressure control valve 47.
The pressure on the outlet side of the branch flow switching valve 14A is equal to the sensing line 2
8 and the pressure control valves 45, 46
As a result, the pressure on the outlet side of the directional control valve groups 9 and 10 is also controlled to be the same as the pressure on the sensing line 28. The discharge flow rate from the hydraulic pump 6 is always the same, and even if the pressure difference between the discharge circuit 12 on the hydraulic pump 6 side and the discharge circuit 11 on the hydraulic pump 1 side changes, the opening areas of the directional control valve groups 9 and 10 And the hydraulic actuator groups 7, 8 on the hydraulic pump 6 side, which is the merging supply side, and the discharge circuit 11 on the hydraulic pump 1 side, which is the merging side, according to the opening area of the variable throttle 150a. 7,
The pressure oil is supplied to the discharge circuit 11 on the hydraulic pump 1 side in accordance with the insufficient flow rate.

On the other hand, when the discharge pressure of the hydraulic pump 6 is lower than the discharge pressure of the hydraulic pump 1, the merging line 13a and the sensing line 28 are communicated by the check valve 53,
The pressure of the sensing line 28 rises to the discharge pressure of the hydraulic pump 1, and the discharge pressure of the hydraulic pump 6 becomes higher than the discharge pressure of the hydraulic pump 1 by the load sensing control, so that the supply of pressure oil from the hydraulic pump 6 becomes possible. . The pressure control valve 47 controls the pressure on the outlet side of the merge / shunt switch valve 14A to be the same as the pressure on the sensing line 28. The pressure control valves 45 and 46 control the pressure on the outlet side of the directional control valve groups 9 and 10. Is also controlled to be the same as the pressure of the sensing line 28, the differential pressure across the diverting / diverting switching valve 14A is always the same as the differential pressure across the directional switching valve groups 9 and 10, and the discharge flow rate from the hydraulic pump 6 is Discharge circuit 1 on hydraulic pump 6 side
Even if the pressure difference between the hydraulic circuit 1 and the discharge circuit 11 on the hydraulic pump 1 side changes, the opening areas of the directional control valve groups 9 and 10 and the variable throttle 150
The hydraulic actuator groups 7, 8 are distributed to the hydraulic actuator groups 7, 8 on the hydraulic pump 6 side, which is the merging supply side, and the discharge circuit 11 on the hydraulic pump 1 side, which is the merging side, in accordance with the opening area of a. Is supplied to the discharge circuit 11 on the hydraulic pump 1 side in accordance with the insufficient flow rate.

Similarly, when the hydraulic pump 6 enters the saturation state and cannot supply the required flow rate of the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side, the load sensing differential pressure ΔP2 decreases, and Flow switching valve 1
4B switches to a merging position where the merging line 13b is communicated via the variable throttle 150b and the merging line 74b is communicated, and the variable throttle 150b is connected to the hydraulic pump 6 side according to the degree of decrease in the load sensing differential pressure ΔP2. The opening area of the hydraulic actuator groups 7 and 8 is set so that the insufficient flow rate with respect to the required flow rate passes.

Here, when the discharge pressure of the hydraulic pump 1 is higher than the discharge pressure of the hydraulic pump 6, the merging line 13b and the sensing line 27 are shut off by the check valve 54, and the pressure of the sensing line 27 is reduced by the hydraulic actuator group 2, 3, and the discharge pressure of the hydraulic pump 1 is the same as before the merge / divide switch valve 14B switches to the merge position. Then, the pressure is controlled by the pressure control valve 48.
The pressure on the outlet side of the branch flow switching valve 14B is the sensing line 2
7 and the pressure control valves 43 and 44
Thus, the pressure on the outlet side of the directional control valve groups 4 and 5 is controlled to be the same as the pressure on the sensing line 27. Therefore, the differential pressure across the diverting / diverting switching valve 14B is different from the differential pressure across the directional switching valve groups 2 and 3. The discharge flow rate from the hydraulic pump 1 is always the same, and even if the pressure difference between the discharge circuit 11 on the hydraulic pump 1 side and the discharge circuit 12 on the hydraulic pump 6 side changes, the opening area of the directional control valve groups 4 and 5 becomes smaller. Hydraulic actuator groups 2, 3 on the hydraulic pump 1 side, which is the merging supply side, according to the opening area of the variable throttle 150b.
Is distributed to the hydraulic circuit 6 and the discharge circuit 12 on the hydraulic pump 6 side. The flow rate of the corresponding pressure oil is supplied.

On the other hand, when the discharge pressure of the hydraulic pump 1 is lower than the discharge pressure of the hydraulic pump 6, the check valve 54 allows the joining line 13b and the sensing line 27 to communicate with each other.
The pressure of the sensing line 27 increases to the discharge pressure of the hydraulic pump 6, and the discharge pressure of the hydraulic pump 1 becomes higher than the discharge pressure of the hydraulic pump 6 by the load sensing control, so that the supply of pressure oil from the hydraulic pump 1 becomes possible. . Then, the pressure on the outlet side of the diverging / diverting switching valve 14B is controlled to be the same as the pressure on the sensing line 27 by the pressure control valve 48, and the pressure on the outlet side of the directional switching valve groups 4 and 5 is controlled by the pressure control valves 43 and 44. Is also controlled to be equal to the pressure of the sensing line 27, the differential pressure across the diverting / diverting switching valve 14B is always the same as the differential pressure across the directional switching valve groups 2 and 3, and the discharge flow rate from the hydraulic pump 1 is Even if the pressure difference between the discharge circuit 11 on the hydraulic pump 1 side and the discharge circuit 12 on the hydraulic pump 6 side changes,
The hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side, which is the merging supply side, and the hydraulic pump 6 on the merging side, according to the opening areas of the direction switching valve groups 4 and 5 and the opening area of the variable throttle 150b.
The hydraulic fluid is appropriately supplied to the hydraulic actuator groups 2 and 3, and the hydraulic fluid is supplied to the hydraulic pump groups 6 and 3 in accordance with the insufficient flow rate. You.

When neither the hydraulic pump 1 nor the hydraulic pump 6 is in the saturation state, the load sensing differential pressure .DELTA.P1 and the load sensing differential pressure .DELTA.P2 become equal. It keeps and shuts off both the merging lines 13a and 13b.

Therefore, according to the present embodiment, the same effects as in the first embodiment can be obtained. In addition, variable throttles 150a and 150b are provided in the merge / diverge switching valves 14A and 14B, and are supplied to the discharge circuit on the merged supply side from the hydraulic pump on the merged supply side according to the degree of saturation of the hydraulic pump on the merged side. Since the flow rate of the pressure oil is changed, it is possible to supply a flow rate corresponding to the insufficient flow rate of the hydraulic actuator group on the merging side.

Further, a merging line 74 branched from the sensing line on the merging supply side and connected to the discharge circuit on the merging side.
a, 74b are provided, and when the merge / diverge switching valves 14A, 14B are switched to the merge position, the merge lines 74a, 7b are provided.
4b also communicates, so even if the discharge pressure of the hydraulic pump on the merged supply side is lower than the discharge pressure of the hydraulic pump on the merged side, the sensing line on the merged supply side is boosted and the hydraulic pump on the merged supply side The discharge pressure can be made higher than the discharge pressure of the hydraulic pump on the merging side, and pressure oil can be supplied from the hydraulic pump on the merging supply side to the discharge circuit on the merging side.

Also, the merge / divide flow switching valves 14A and 14B are
Load sensing differential pressure ΔP1 and load sensing differential pressure Δ
When the hydraulic pump 1 and the hydraulic pump 6 are in substantially the same saturation state, both the merge / divide flow switching valves 14A and 14B can be maintained at the branch positions, so that there is no margin when the hydraulic pump 1 and the hydraulic pump 6 are both in the same saturation state. Regardless of the merging, the hydraulic actuator group on the merging supply side does not run out of the supply flow rate, so that a more appropriate merging can be performed.

A third embodiment of the present invention will be described with reference to FIG. In the figure, the same members as those shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 3, this embodiment is different from the second embodiment shown in FIG. 2 in that an operation lever group including operation levers 26a and 26b for operating the directional control valve groups 4 and 5 (hereinafter referred to as "operation lever group").
Operating lever groups 26a and 26b), operating lever groups including operating levers 26c and 26d for operating the directional switching valve groups 9 and 10 (hereinafter referred to as operating lever groups 26c and 26d), and operating lever groups 26a and 26b. A pilot line 98 for detecting the highest pilot pressure among the pilot pressures respectively generated according to the operation amount, and a highest pilot pressure among the pilot pressures respectively generated for the operation amounts of the operation lever groups 26c and 26d are detected. A pilot line 99, a bypass line 88 branched from the discharge circuit 11 of the hydraulic pump 1 and connected to the tank 180,
Branching from the discharge circuit 12 of the hydraulic pump 6
And a pressure control valve 55, 56 instead of the LS control valve 20, 24.

The bypass line 88 is provided with a variable throttle 80 in which the pilot pressure of the pilot line 98 acts and the opening area decreases as the pilot pressure increases.
, Which is located at the exit side of the variable aperture 80 and generates pressure on the exit side of the variable aperture 80, and is located between the variable aperture 80 and the aperture 84, and the pressure of the sensing line 27 acts on the exit side of the variable aperture 80. And a pressure control valve 82 that controls the same pressure as the pressure of the sensing line 27.

Similarly, the bypass line 89
Also, a variable throttle 81 which has a smaller opening area as the pilot pressure of the pilot line 99 acts and the pilot pressure is higher, and which is located at the outlet side of the variable throttle 81,
A throttle 85 that generates pressure on the outlet side of the
And a pressure control valve 83 which is located between the diaphragm 85 and the pressure of the sensing line 28 and controls the pressure on the outlet side of the variable diaphragm 81 to be the same as the pressure of the sensing line 28.

The discharge amount control means of the hydraulic pump 1 in this embodiment is a pressure detection valve 55 and a servo mechanism 29A. The pressure detection valve 55 is connected to a pilot line 86 branched from the inlet side of the throttle 84, and The pressure generated at 84 (hereinafter referred to as the negative control pressure on the hydraulic pump 1 side) is detected, and the servo mechanism 29A controls the tilting of the hydraulic pump 1 according to the negative control pressure detected by the pressure detection valve 55.

Further, the discharge amount control means of the hydraulic pump 6 in the present embodiment includes the pressure detection valve 56 and the servo mechanism 42A.
The pressure detection valve 56 is connected to a pilot line 87 branched from the inlet side of the throttle 85, detects the pressure generated in the throttle 85 (hereinafter, referred to as a negative control pressure on the hydraulic pump 6 side), and the servo mechanism 42A The tilt of the hydraulic pump 6 is controlled in accordance with the negative control pressure detected by the pressure detection valve 55.

That is, in this embodiment, the discharge flow rates of the hydraulic pumps 1 and 6 are controlled by negative flow rate control.

Further, between the discharge circuit 11 of the hydraulic pump 1 and the discharge circuit 12 of the hydraulic pump 6 and the sensing line 2
7 and the sensing line 28 are provided with a merging circuit 100B.
Is provided. The merging circuit 100B is a combination of the merging / shunting switching valve 14A, 14A in the merging circuit 100A of the second embodiment.
14B is replaced with a merge / shunt switch valve 14C, 14D.
Same as 00A.

The merging / shunting switching valve 14C is connected to the merging line 13
a and 74a, and a variable throttle 150
This is a four-port two-position switching valve that can be switched to a merging position where the merging line 13a is communicated via a and the merging line 74a is communicated through the a.

The merge / divide switch valve 14D is also connected to the merge line 13
b and 74b, and a variable flow restrictor 150
This is a four-port two-position switching valve that can be switched to a merging position where the merging line 13b communicates with the merging line 13b and the merging line 74b communicates with the merging line 13b.

The merge / divide switch valve 14C is of a hydraulic pilot switching type, in which the negative control pressure of the hydraulic pump 1 is guided to one side and the spring 65 is switched to the other side.
When the negative control pressure on the hydraulic pump 1 side is maintained at a predetermined value (set pump control pressure) set by the spring 65, the hydraulic pump 1 is at the branch position, and the negative control pressure on the hydraulic pump 1 side is reduced by the spring 65. When it becomes lower than the predetermined value (set pump control pressure) set in the above, it switches to the merge position. Combination
The diversion switching valve 14D is also of a hydraulic pilot switching type, in which a negative control pressure on the hydraulic pump 6 side is guided to one side, and a spring 66 is provided on the other side, and the negative control pressure on the hydraulic pump 6 side is controlled by a spring. When it is maintained at the predetermined value (set pump control pressure) set at 66, it is at the branch position, and when the negative control pressure on the hydraulic pump 6 side becomes lower than the predetermined value (set pump control pressure) set by the spring 66. Switches to the merging position. That is, the merge / shunt switch valve 1
The pilot lines 86 and 87 associated with the drive units at both ends of 4C and 14D constitute merge / shunt switching control means as switching means for these.

The variable throttle 150a is connected to the hydraulic pump 1
The opening area is increased as the negative control pressure on the side of the hydraulic pump 1 becomes lower than the set pump control pressure, so that an insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side is set. Is set so that the opening area is increased as the negative control pressure on the hydraulic pump 6 side becomes lower than the set pump control pressure, so that the insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side passes. I have. Therefore,
The merge / divide flow switching valve 14C is provided with the hydraulic actuator groups 2 and 3
In accordance with the required flow rate, the stroke position is changed, and the opening area of the built-in variable throttle 150a is increased in accordance with the stroke position. By changing the stroke position, the opening area of the built-in variable diaphragm 150b is increased in accordance with the stroke position.

In the present embodiment configured as described above, when the hydraulic pump 1 enters the saturation state and cannot supply the required flow rate of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side, the hydraulic pump 1 Side negative control pressure becomes lower than the set pump control pressure, and the merge / divide switch valve 14C is connected to the merge line 13 via the variable throttle 150a.
a and the converging line 74a is switched to the converging position, and the variable throttle 150a requests the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side according to the degree of decrease in the negative control pressure on the hydraulic pump 1 side. The opening area is set so that the insufficient flow rate with respect to the flow rate passes.

As in the second embodiment, the discharge flow rate from the hydraulic pump 6 changes even when the pressure difference between the discharge circuit 12 on the hydraulic pump 6 side and the discharge circuit 11 on the hydraulic pump 1 side changes. According to the opening areas of the direction switching valve groups 9 and 10 and the opening area of the variable throttle 150a, the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side which is the merging supply side and the discharge circuit on the hydraulic pump 1 side which is the merging side. Therefore, the pressure oil is appropriately supplied to the hydraulic actuator groups 7 and 8 and the flow rate of the pressure oil corresponding to the insufficient flow rate is supplied to the discharge circuit 11 on the hydraulic pump 1 side.

Similarly, when the hydraulic pump 6 enters the saturation state and cannot supply the required flow rate of the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side, the negative control pressure on the hydraulic pump 6 side sets the pump control. When the pressure becomes lower than the pressure, the merge / divide switch valve 14D connects the merge line 13b through the variable throttle 150b and the merge line 74b.
b to the converging position where the b
In b, the opening area is set according to the degree of reduction of the negative control pressure on the hydraulic pump 6 side so that the insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side passes.

In the same manner as in the second embodiment, the discharge flow rate from the hydraulic pump 1 changes even if the pressure difference between the discharge circuit 11 on the hydraulic pump 1 side and the discharge circuit 12 on the hydraulic pump 6 side changes. Opening area of directional control valve groups 4 and 5 and variable throttle 15
Hydraulic pump 1 on the merging supply side according to the opening area of 0b
The hydraulic fluid is distributed to the hydraulic actuator groups 2 and 3 and the discharge circuit 12 of the hydraulic pump 6 which is the merging side, so that the hydraulic oil is appropriately supplied to the hydraulic actuator groups 2 and 3 and the hydraulic pump 6 is discharged. The flow rate of the pressure oil corresponding to the insufficient flow rate is supplied to the circuit 12.

When neither the hydraulic pump 1 nor the hydraulic pump 6 is in the saturation state, the negative control pressure on the hydraulic pump 1 side and the negative control pressure on the hydraulic pump 6 side are both maintained at the set pump control pressure. -Both the diversion switching valves 14A and 14B are maintained at the diversion position, and the merging line 1
Both 3a and 13b are shut off.

Therefore, the present embodiment can provide the same effects as those of the second embodiment.

A fourth embodiment of the present invention will be described with reference to FIGS. In the figure, the same members as those shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 4, the present embodiment is different from the second embodiment shown in FIG. 2 in that pressure sensors 34 and 35 for detecting the discharge pressures of the hydraulic pumps 1 and 6 and pressures in the sensing lines 27 and 28 respectively. Sensors 37 and 37, respectively, and a merging / diverting switching control circuit 200 including the electromagnetic switching valves 15a and 15b and the controller 17 as switching means of the merging / diverting switching valves 14E and 14F of the merging circuit 100C described below. In addition, the LS control valve 20,
24, and the pressure sensors 34 to 37
Is input to the controller 17.

The control of the discharge flow rate of the hydraulic pumps 1 and 6 in this embodiment is load sensing control as in the second embodiment, but the control is an electrical control. The amount control means includes a pressure sensor 3
4, 36, the controller 17, and the servo mechanism 29B.
5, 37, the controller 17, and the servo mechanism 42B.

Also, between the discharge circuit 11 of the hydraulic pump 1 and the discharge circuit 12 of the hydraulic pump 6 and the sensing line 2
7 and the sensing line 28 are connected by a merging circuit 100C.
The merging circuit 100C is provided with merging / diverting switching valves 14E, 14F instead of the merging / diverting switching valves 14A, 14B in the second embodiment, and the other configuration is the same as that of the second embodiment. This is the same as the merge circuit 100A in the embodiment.

The merging / diverting switching valve 14E is connected to the merging line 13
a and 74a, and a variable throttle 150
This is a four-port two-position switching valve that can be switched to a merging position where the merging line 13a is communicated via a and the merging line 74a is communicated through the a.

The junction / shunt switching valve 14F is also connected to the junction line 13
b and 74b, and a variable flow restrictor 150
This is a four-port two-position switching valve that can be switched to a merging position where the merging line 13b communicates with the merging line 13b and the merging line 74b communicates with the merging line 13b.

The diverging / diverting switching valves 14E and 14F are switched from the diverting position to the merging position by the pilot pressure sent from the hydraulic pilot pump 16 via the electromagnetic switching valves 15a and 15b, and the solenoids of the electromagnetic switching valves 15a and 15b are controlled by the controller. It is excited by the output current from 17.

The switching control of the merge / divide switch valves 14E and 14F by the merge / divide switch control circuit 200 will be described below with reference to FIG. Here, FIG. 5 is a diagram showing processing contents in the controller 17.

As shown in FIG. 5, in the controller 17, the discharge pressure of the hydraulic pump 1 and the sensing line 27 on the hydraulic pump 1 side are determined by signals from the pressure sensors 34 and 36.
When the pressure difference .DELTA.PLS from the set pressure is smaller than a predetermined value (load sensing set differential pressure), the hydraulic pump 1 is determined to be in the saturation state, and the difference .DELTA..DELTA.PLS between the load sensing set differential pressure and the differential pressure .DELTA.PLS is calculated, and the difference is calculated. The variable throttle 150 is adjusted so that an insufficient flow rate corresponding to the required flow rate of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side passes from ΔΔPLS.
a is calculated, and the calculated opening area A is calculated.
The current value I of the current output to the electromagnetic switching valve 15a is calculated so that
output to a.

As a result, the diverging / diverting switching valve 14E is switched to the merging position, and the opening area of the diverting / diverting switching valve 14E is changed to the variable throttle 150a.
Is set such that the insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side passes.

In the same manner as in the second embodiment, the discharge flow rate from the hydraulic pump 6 changes even when the pressure difference between the discharge circuit 12 on the hydraulic pump 6 side and the discharge circuit 11 on the hydraulic pump 1 side changes. According to the opening areas of the direction switching valve groups 9 and 10 and the opening area of the variable throttle 150a, the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side which is the merging supply side and the discharge circuit on the hydraulic pump 1 side which is the merging side. Therefore, the pressure oil is appropriately supplied to the hydraulic actuator groups 7 and 8 and the flow rate of the pressure oil corresponding to the insufficient flow rate is supplied to the discharge circuit 11 on the hydraulic pump 1 side.

Similarly, in the controller 17,
When the pressure difference ΔPLS between the discharge pressure of the hydraulic pump 6 and the pressure of the sensing line 28 on the hydraulic pump 6 side becomes smaller than a predetermined value (load sensing set differential pressure) by the signals from the pressure sensors 35 and 37, the hydraulic pump 6 is saturated. State is determined, and the load sensing set differential pressure and differential pressure Δ
The difference .DELTA..DELTA.PLS from the PLS is calculated, and according to the difference .DELTA..DELTA.PLS, the variable throttle 1 is adjusted so that the insufficient flow with respect to the required flow of the hydraulic actuator groups 7, 8 of the hydraulic pump 6 passes.
The opening area A of the solenoid valve 50b is calculated, the current value I of the current output to the electromagnetic switching valve 15b is calculated so that the calculated opening area A is obtained, and the current of the current value I is output to the electromagnetic switching valve 15b. I do.

As a result, the diverging / diverting switching valve 14F is switched to the merging position, and the opening area of the diverting / diverting valve 14F is changed by the variable throttle 150b.
Is set such that the insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side passes.

In the same manner as in the second embodiment, the discharge flow rate from the hydraulic pump 1 changes even when the pressure difference between the discharge circuit 11 on the hydraulic pump 1 side and the discharge circuit 12 on the hydraulic pump 6 side changes. Opening area of directional control valve groups 4 and 5 and variable throttle 15
Hydraulic pump 1 on the merging supply side according to the opening area of 0b
The hydraulic fluid is distributed to the hydraulic actuator groups 2 and 3 and the discharge circuit 12 of the hydraulic pump 6 which is the merging side, so that the hydraulic oil is appropriately supplied to the hydraulic actuator groups 2 and 3 and the hydraulic pump 6 is discharged. The flow rate of the pressure oil corresponding to the insufficient flow rate is supplied to the circuit 12.

Further, the differential pressure between the discharge pressure of the hydraulic pump 1 and the pressure of the sensing line 27 is maintained at the load sensing differential pressure, and the differential pressure between the discharge pressure of the hydraulic pump 6 and the pressure of the sensing line 28 is also loaded. When the differential pressure is maintained at the sensing set pressure, the controller 17 controls the hydraulic pump 1
And the hydraulic pump 6 are not in the saturation state, the solenoids of the electromagnetic switching valves 15a and 15b are not energized, and the diverting / diverting switching valves 14E and 14F are both kept at the diverting position, and the convergence lines 13a and 13b are both shut off. I do.

Therefore, the present embodiment can provide the same effects as the second embodiment, and in this embodiment, the load sensing control and the switching control of the merge / divide switching valve are performed by electric control. It is possible to easily detect the saturation state of the pump and set the opening area of the variable throttle of the merge / shunt switch valve.

Further, both the load sensing control and the switching control of the merge / shunt switching valve are not limited to only the hydraulic pressure or only the electric power, but may be a combination of the hydraulic pressure and the electric power.

A fifth embodiment of the present invention will be described with reference to FIGS. In the figure, the same members as those shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 6, this embodiment is different from the third embodiment shown in FIG. 3 in that pressure sensors 39 and 40 for detecting the negative control pressures on the hydraulic pumps 1 and 6 side, respectively, and a merging circuit 100D described later. Merging / shunting switching valves 14G, 14H
/ Shunt switching control circuit 20 including electromagnetic switching valves 15a, 15b and controller 17A as switching means
0A and electromagnetic switching valves 15c and 15d for operating the variable throttles 80 and 81, respectively.
56 and the pressure sensors 39, 40
Are input to the controller 17, and signals generated respectively by the operation lever groups 26 a, 26 b, 26 c, and 26 d according to the operation amounts are also input to the controller 17.

The variable throttles 80 and 81 change their opening areas according to the magnitude of the pilot pressure sent from the hydraulic pilot pump 16 via the electromagnetic switching valves 15c and 15d, respectively, and the electromagnetic switching valves 15c and 15d The pilot pressure to be sent to the variable throttles 80 and 81 is changed according to the magnitude of the output current from the controller 17A, and the output current from the controller 17A to the electromagnetic switching valve 15c is changed by the controller 17 according to the signals from the operation lever groups 26a and 26b.
A, the output current from the controller 17A to the electromagnetic switching valve 15d is also calculated by the controller 17A in accordance with signals from the operation lever groups 26c, 26d.
That is, the variable throttles 80 and 81 are controlled by the controller 17 and the electromagnetic switching valves 15c and 15d such that the opening area decreases as the operation amount of the corresponding operation lever group increases.

The control of the discharge flow rate of the hydraulic pumps 1 and 6 in the present embodiment is negative flow rate control as in the third embodiment, but the control is an electrical control. The amount control means includes a pressure sensor 39
And the controller 17A and the servo mechanism 29C. The discharge amount control means of the hydraulic pump 6 is the pressure sensor 40, the controller 17A and the servo mechanism 42C.

Also, between the discharge circuit 11 of the hydraulic pump 1 and the discharge circuit 12 of the hydraulic pump 6 and the sensing line 2
7 and the sensing line 28 are connected to a merging circuit 100D.
The merging circuit 100D is provided with merging / shunting switching valves 14G, 14H instead of the merging / shunting switching valves 14C, 14D in the third embodiment, and the other configuration is the same as that of the third embodiment. This is the same as the merging circuit 100B in the embodiment.

The merge / divide switch valve 14G is connected to the merge line 13
a and 74a, and a variable throttle 150
This is a four-port two-position switching valve that can be switched to a merging position where the merging line 13a is communicated via a and the merging line 74a is communicated through the a.

The merge / divide switch valve 14H is also connected to the merge line 13
b and 74b, and a variable flow restrictor 150
This is a four-port two-position switching valve that can be switched to a merging position where the merging line 13b communicates with the merging line 13b and the merging line 74b communicates with the merging line 13b.

[0102] The joining / diverting switching valves 14G and 14H are switched from the dividing position to the joining position by the pilot pressure sent from the hydraulic pilot pump 16 via the electromagnetic switching valves 15a and 15b, respectively, and the solenoids of the electromagnetic switching valves 15a and 15b are switched. It is excited by the output current from the controller 17A.

The switching control of the merge / divide switch valves 14G, 14H by the merge / divide switch control circuit 200A will be described below with reference to FIG. Here, FIG. 7 is a diagram showing processing contents in the controller 17A.

As shown in FIG. 7, when the negative control pressure on the hydraulic pump 1 side becomes lower than a predetermined value (set pump control pressure) by the signal from the pressure sensor 39, the controller 17A determines that the hydraulic pump 1 is in the saturation state. Difference Δ between the set pump control pressure and the negative control pressure
PN is calculated, and according to the difference ΔPN, the opening area A of the variable throttle 150a is adjusted so that the insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side passes.
Is calculated, the current value I of the current output to the electromagnetic switching valve 15a is calculated so that the calculated opening area A is obtained, and the current having the current value I is output to the electromagnetic switching valve 15a.

As a result, the diverging / diverting switching valve 14G is switched to the merging position, and the opening area of the diverting / diverting valve 14G is changed to
Is set such that the insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side passes.

In the same manner as in the third embodiment, the discharge flow rate from the hydraulic pump 6 changes even when the pressure difference between the discharge circuit 12 on the hydraulic pump 6 side and the discharge circuit 11 on the hydraulic pump 1 side changes. According to the opening areas of the direction switching valve groups 9 and 10 and the opening area of the variable throttle 150a, the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side which is the merging supply side and the discharge circuit on the hydraulic pump 1 side which is the merging side. Therefore, the pressure oil is appropriately supplied to the hydraulic actuator groups 7 and 8 and the flow rate of the pressure oil corresponding to the insufficient flow rate is supplied to the discharge circuit 11 on the hydraulic pump 1 side.

Similarly, in the controller 17A, when the negative control pressure on the hydraulic pump 6 side becomes lower than a predetermined value (set pump control pressure) by the signal from the pressure sensor 40, the hydraulic pump 6 is determined to be in the saturation state, and the set pump Difference ΔP between control pressure and the negative control pressure
N is calculated, and the opening area A of the variable throttle 150b is calculated in accordance with the difference ΔPN so that an insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side is calculated. The current value I of the current output to the electromagnetic switching valve 15b is calculated so that the opening area A is obtained.
The current having the current value I is output to the electromagnetic switching valve 15b.

As a result, the diverging / diverting switching valve 14H is switched to the merging position, and the opening area of the diverting / diverting valve 14H is changed to
Is set such that the insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side passes.

In the same manner as in the third embodiment, the discharge flow rate from the hydraulic pump 1 changes even if the pressure difference between the discharge circuit 11 on the hydraulic pump 1 side and the discharge circuit 12 on the hydraulic pump 6 side changes. Opening area of directional control valve groups 4 and 5 and variable throttle 15
Hydraulic pump 1 on the merging supply side according to the opening area of 0b
The hydraulic fluid is distributed to the hydraulic actuator groups 2 and 3 and the discharge circuit 12 of the hydraulic pump 6 which is the merging side, so that the hydraulic oil is appropriately supplied to the hydraulic actuator groups 2 and 3 and the hydraulic pump 6 is discharged. The flow rate of the pressure oil corresponding to the insufficient flow rate is supplied to the circuit 12.

When the negative control pressures of the hydraulic pumps 1 and 6 are both maintained at the set pump control pressure, the controller 17A determines that neither the hydraulic pump 1 nor the hydraulic pump 6 is in the saturation state, and the electromagnetic switching valve Fifteen
a / Diversion switching valve 1 without exciting solenoids a and 15b
4G and 14H are both kept at the branching position,
Both a and 13b are shut off.

Therefore, the present embodiment can provide the same effects as those of the second embodiment, and in this embodiment, the negative flow rate control and the switching control of the diverting / diverting switching valve are performed by electric control. It is possible to easily detect the saturation state of the pump and set the opening area of the variable throttle of the merge / shunt switch valve.

Further, the negative flow rate control and the switching control of the merge / divide flow switching valve are not limited to only the hydraulic pressure or only the electric power, but may be a combination of the hydraulic pressure and the electric power.

The sixth embodiment of the present invention will be described with reference to FIGS. In the figure, members that are the same as those shown in FIG. 6 are given the same reference numerals, and descriptions thereof will be omitted.

In FIG. 8, the present embodiment is different from the fifth embodiment shown in FIG. 6 in that bypass lines 86 and 87 and pressure sensors 39 and 40 are employed.

The control of the discharge flow rate of the hydraulic pumps 1 and 6 in this embodiment is different from that of the fifth embodiment in that the operation lever groups 26a, 26b and 2 input to the controller 17B are controlled.
This is a positive flow rate control that determines the discharge flow rate of the hydraulic pumps 1 and 6 according to the operation amounts of 6c and 26d. In this embodiment, the discharge amount control means of the hydraulic pump 1 is the controller 17B and the servo mechanism 29D, and the discharge amount control means of the hydraulic pump 6 is the controller 17B and the servo mechanism 42D.
It is.

The switching control of the merge / divide switch valves 14G and 14H by the merge / divide switch control circuit 200B will be described below with reference to FIG. Here, FIG. 9 is a diagram showing the processing contents in the controller 17B.

As shown in FIG. 9, the controller 17B calculates the required flow rate Qa of the hydraulic actuator 2 based on a signal from the operation lever 26a,
From the hydraulic actuator 3 by the signal from the
Is calculated, and the required flow rate Qa and the required flow rate Qb are added to obtain the required flow rate Q1 of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side. The tilting position of the hydraulic pump 1 and the prime mover 3
The discharge flow rate Q1 'of the hydraulic pump 1 is obtained from the number of revolutions of 8, and the required flow rate Q1 is compared with the discharge flow rate Q1'. If the required flow rate Q1 is larger than the discharge flow rate Q1 ', the hydraulic pump 1
Is determined to be in the saturation state, and the opening of the variable throttle 150a is adjusted so that the insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side passes according to the difference ΔQP between the required flow rate Q1 and the discharge flow rate Q1 '. The area A is calculated, the current value I of the current output to the electromagnetic switching valve 15a is calculated so that the calculated opening area A is obtained, and the current having the current value I is output to the electromagnetic switching valve 15a.

As a result, the diverging / diverting switching valve 14G is switched to the merging position, and the opening area of the diverting / diverting valve 14G is changed by the variable throttle 150a.
Is set such that the insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side passes.

As in the fifth embodiment, the discharge flow rate from the hydraulic pump 6 changes even when the pressure difference between the discharge circuit 12 on the hydraulic pump 6 side and the discharge circuit 11 on the hydraulic pump 1 side changes. According to the opening areas of the direction switching valve groups 9 and 10 and the opening area of the variable throttle 150a, the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side which is the merging supply side and the discharge circuit on the hydraulic pump 1 side which is the merging side. Therefore, the pressure oil is appropriately supplied to the hydraulic actuator groups 7 and 8 and the flow rate of the pressure oil corresponding to the insufficient flow rate is supplied to the discharge circuit 11 on the hydraulic pump 1 side.

Similarly, in the controller 17B, the required flow rate Qc of the hydraulic actuator 7 is calculated based on the signal from the operating lever 26c, and the required flow rate Qd of the hydraulic actuator 8 is calculated based on the signal from the operating lever 26d. And the required flow Qd are added to obtain the required flow Q2 of the hydraulic actuator groups 7, 8 on the hydraulic pump 6 side, and the tilting position of the hydraulic pump 6 and the prime mover 38
The discharge flow rate Q2 'of the hydraulic pump 6 is obtained from the rotation speed of the hydraulic pump 6, and the required flow rate Q2 is compared with the discharge flow rate Q2'. When the required flow rate Q2 is larger than the discharge flow rate Q2 ', the hydraulic pump 6
Is determined to be in a saturation state, and the opening of the variable throttle 150b is adjusted so that the insufficient flow with respect to the required flow of the hydraulic actuator groups 7, 8 on the hydraulic pump 6 side passes according to the difference ΔQP between the required flow Q2 and the discharge flow Q2 '. The area A is calculated, the current value I of the current output to the electromagnetic switching valve 15b is calculated so that the calculated opening area A is obtained, and the current having the current value I is output to the electromagnetic switching valve 15b.

As a result, the diverging / diverting switching valve 14H is switched to the merging position, and the opening area of the diverting / diverting valve 14H is changed by the variable throttle 150b.
Is set such that the insufficient flow rate with respect to the required flow rate of the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side passes.

In the same manner as in the fifth embodiment, the discharge flow rate from the hydraulic pump 1 changes even if the pressure difference between the discharge circuit 11 on the hydraulic pump 1 side and the discharge circuit 12 on the hydraulic pump 6 side changes. Opening area of directional control valve groups 4 and 5 and variable throttle 15
Hydraulic pump 1 on the merging supply side according to the opening area of 0b
The hydraulic fluid is distributed to the hydraulic actuator groups 2 and 3 and the discharge circuit 12 of the hydraulic pump 6 which is the merging side, so that the hydraulic oil is appropriately supplied to the hydraulic actuator groups 2 and 3 and The flow rate of the pressure oil corresponding to the insufficient flow rate is supplied to the circuit 12.

The required flow rate Q 1 of the hydraulic actuator groups 2 and 3 on the hydraulic pump 1 side is equal to the discharge flow rate Q of the hydraulic pump 1.
When the required flow rate Q2 of the hydraulic actuator groups 7 and 8 on the hydraulic pump 6 side is smaller than 1 'and the discharge flow rate Q2' of the hydraulic pump 6, both the hydraulic pump 1 and the hydraulic pump 6 are brought into the saturation state by the controller 17B. If not, the solenoids of the electromagnetic switching valves 15a and 15b are not energized, and the diverging / diverting switching valves 14G and 14H are both kept at the diverting position, and the convergence lines 13a and 13b are both shut off.

Therefore, according to the present embodiment, the same effects as those of the fifth embodiment can be obtained.

[0125]

According to the present invention, in a hydraulic drive device capable of merging the discharge flow rates of two hydraulic pumps and supplying them to a plurality of hydraulic actuators, the discharge flow rate of the hydraulic pump on the merging supply side at the time of merging is determined. Pressure oil can be appropriately supplied to the hydraulic actuator on the merging supply side, and the hydraulic oil can also be merged and supplied to the discharging circuit on the merging side. can do.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a hydraulic control circuit of a hydraulic drive device according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a hydraulic control circuit of a hydraulic drive device according to a third embodiment of the present invention.

FIG. 4 is a diagram illustrating a hydraulic control circuit of a hydraulic drive device according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing control contents of a controller 17 shown in FIG.

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

FIG. 7 is a block diagram showing control contents of a controller 17A shown in FIG.

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

FIG. 9 is a block diagram showing control contents of a controller 17B shown in FIG.

FIG. 10 is a diagram showing a merging / diverting system of a plurality of hydraulic pumps in a conventional hydraulic drive device.

[Explanation of symbols]

1,6 Hydraulic pump 2,3,7,8 Hydraulic actuator 4,5,9,10 Directional switching valve 11,12 Discharge circuit 13,13a, 13b Merging line 14a, 14b, 14A-14H Merging / diverting switching valve 15a- 15d Electromagnetic switching valve 16 Hydraulic pilot pump 17, 17A, 17B Controller 18, 23 Pilot line 26a-26d Operating lever 27, 28 Sensing line 27a, 27b, 28a, 28b Check valve 20, 24 LS control valve 29, 29A-29D Servo Mechanism 34-37 Pressure sensor 38 Prime motor 39, 40 Pressure sensor 43-48 Pressure control valve 50a, 50b Restriction 51, 52, 53, 54 Check valve 55, 56 Pressure detection valve 65, 66 Spring 70, 70a, 70b Merging line 71 Merging line 74a, 74b Merging line 76,77 Spring 80,81 Variable throttle 82,83 Pressure control valve 84,85 Throttle 86,87 Pilot line 88,89 Bypass line 98,99 Pilot line 100,100A-100D Merging circuit 110,111 Bypass valve 150a, 150b Variable Restrictors 180, 181 Tanks 200, 200A, 200B Combination / diversion switching control circuits 301a, 301b, 302a, 302b Direction switching sections 303a, 303b, 304a, 304b Variable restrictors 307a, 307b, 308a, 308b Speed setting devices

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideyo Kato 650 Kandamachi, Tsuchiura-shi, Ibaraki Pref.

Claims (6)

[Claims] A first and a second variable displacement hydraulic pump; a first and a second hydraulic actuator group respectively driven by pressure oil discharged from the first and the second hydraulic pump; From the first and second hydraulic pumps to the first
A first and a second direction switching valve group for controlling a flow of pressure oil supplied to a second and a second hydraulic actuator group;
To detect the maximum load pressure of a group of hydraulic actuators
, A second sensing line for detecting the maximum load pressure of the second hydraulic actuator group, and a pressure on the outlet side of the first directional control valve group,
A first pressure control valve that controls the same pressure as the sensing line pressure, and a second pressure control valve that controls the outlet side pressure of the second direction switching valve group to the same pressure as the second sensing line pressure.
A pressure control valve for controlling a discharge flow rate of the first and second hydraulic pumps according to a required flow rate of the first and second hydraulic actuator groups, wherein the first hydraulic pump A merging line that connects the discharge circuit of the second hydraulic pump and the discharge circuit of the second hydraulic pump, a merging position that is arranged in the merging line and that interrupts both the discharge circuits, and a merging position that communicates the two discharge circuits via a throttle. And a third switch for controlling the pressure on the outlet side of the merge / shunt switch to be the same as the pressure of the sensing line corresponding to the other hydraulic pump when switched to the merge position. A confluence circuit including a pressure control valve, and that one of the first and second hydraulic pumps cannot supply the required flow rate of the hydraulic actuator group on the hydraulic pump side. , The hydraulic drive system, characterized in that it comprises a case-shunt switching control means for switching said multiplexer-diversion switching valve to the merge position. 2. The hydraulic drive according to claim 1, wherein
The merge / shunt switch valve is a valve that changes a stroke position according to a required flow rate of the hydraulic actuator group,
The hydraulic drive device according to claim 1, wherein the aperture is a variable aperture that increases an opening area according to a stroke position. 3. The hydraulic drive device according to claim 1, wherein a discharge flow rate of the first hydraulic pump is controlled so that a pump discharge pressure is higher than a pressure of the first sensing line. Discharge amount control means, and second discharge amount control means for controlling a discharge flow rate of the second hydraulic pump so that a pump discharge pressure is higher than a pressure of the second sensing line. The diversion switching control means switches the merging / diverting switching valve to the merging position when the pressure difference between the discharge pressure of the one hydraulic pump and the pressure of the sensing line on the one hydraulic pump side is smaller than a predetermined value. A hydraulic drive device characterized by the above-mentioned. 4. The hydraulic drive device according to claim 1, wherein the first and second hydraulic pumps each have a first and a second bypass line branched from a discharge circuit and connected to a tank. A first variable throttle provided on one bypass line and reducing an opening area when the operation amount of the first direction switching valve group is increased; and a second variable switch provided on the second bypass line and provided on the second bypass line. A second variable throttle that reduces the opening area when the operation amount of the valve group increases, and first and second variable throttles that are respectively provided at the outlet sides of the first and second variable throttles and generate pressure at their outlet sides. A second throttle, which is provided between the first variable throttle and the first throttle, controls the pressure on the outlet side of the first variable throttle to be the same as the pressure on the first sensing line. A fourth pressure control valve; A fifth pressure control valve provided between the second variable throttle and the second throttle to control the pressure on the outlet side of the second variable throttle to be equal to the pressure of the second sensing line. A first discharge amount control means for detecting a pressure generated in the first throttle, and controlling a discharge flow rate of the first hydraulic pump in accordance with the detected pressure;
And a second discharge amount control means for detecting a pressure generated by the throttle and controlling a discharge flow rate of the second hydraulic pump in accordance with the detected pressure. A hydraulic drive device that switches the merge / shunt switch valve to the merge position when a pressure generated by a throttle provided in a bypass line on the hydraulic pump side becomes lower than a predetermined value. 5. The hydraulic drive device according to claim 3, wherein the merge / shunt switch valve is located at the merge position.
A hydraulic drive device, wherein a discharge circuit of the one hydraulic pump and a sensing line on the other hydraulic pump side are connected to the merge / shunt switch valve. 6. The hydraulic drive device according to claim 1, wherein the first and second operation lever groups respectively operate the first and second direction switching valve groups, and the first operation lever group. A first discharge amount control means for controlling a discharge flow rate of the first hydraulic pump in accordance with the command signal, and a command signal from the second operation lever group, And a second discharge amount control means for controlling a discharge flow rate of the second hydraulic pump in accordance with the command signal, wherein the merge / divide flow switching control means includes an operation lever group of the one hydraulic pump side. A required flow rate of the hydraulic actuator group on the hydraulic pump side is determined by a command signal, and when the determined required flow rate is greater than the discharge flow rate of the one hydraulic pump, switching the merge / divide switch valve to the merge position. Special Hydraulic drive system according to.