WO1998041765A1

WO1998041765A1 - Pressure oil supplying apparatus

Info

Publication number: WO1998041765A1
Application number: PCT/JP1998/001043
Authority: WO
Inventors: Nobumi Yoshida; Hiroshi Endo
Original assignee: Komatsu Ltd.
Priority date: 1997-03-14
Filing date: 1998-03-12
Publication date: 1998-09-24
Also published as: JPH10252705A; KR19980079912A

Abstract

A pressure oil supplying apparatus comprises variable displacement type hydraulic pump units (10) having a common drive shaft and a plurality of independent discharge ports (10a, 10b), a plurality of circuits (11, 12) connecting a plurality of actuators (17, 18), respectively, to the plurality of discharge ports, operating valves (13, 14) respectively provided on the plurality of circuits, pressure compensating valves (15, 16) respectively provided on the plurality of circuits and set at the highest load pressure for the plurality of actuators, and a confluence valve (19) provided between the plurality of circuits for shutting off the plurality of circuits when the plurality of discharge ports are equal in pressure to one another and for providing communication therebetween when pressure differences are produced between the discharge ports.

Description

Description Pressure oil supply device Technical field

The present invention relates to a pressure oil supply device that distributes and supplies pressure oil discharged from a hydraulic pump to a plurality of actuators. Background art

If the hydraulic pressure discharged from the hydraulic pump is supplied simultaneously to a plurality of factories with different loads, the pressure oil is supplied only to the factories with the smallest load, and the pressure oil is not supplied to other factories.

Therefore, as shown in FIG. 1, the first operating valve 2 and the second operating valve 3 are connected in parallel to the discharge path 1 a of the hydraulic pump 1, and the first and second operating valves 2 and 3 are connected to the first and second operating valves 2 and 3. The pressure compensating valves 6 and 6 are provided in the circuits connecting the second actuators 4 and 5, respectively, so that the load pressure of the first actuator 4 and the load pressure of the second It is known that the pressure is detected by a shuttle valve 7 and the detected pressure is supplied to a pressure receiving portion 6a of both pressure compensating valves 6,6.

In the case of the one shown in Fig. 1, both pressure compensating valves 6 and 6 are set at the highest load pressure, so the first and second flow compensating valves 6 and 6 have the first flow rate distribution ratio corresponding to the opening degree of the second operating valves 2 and 3. · With such a hydraulic oil supply device that can supply hydraulic oil to the second factories 4 and 5, the opening area of the low-pressure side pressure compensating valve 6 is small, and high-pressure fluid flows through the pressure compensating valve 6. So low Since the high-pressure fluid is throttled by the pressure compensating valve 6 on the pressure side, the loss is large.

Therefore, an object of the present invention is to provide a pressure oil supply device capable of solving the above-mentioned problem. Disclosure of the invention

A first aspect of the pressure oil supply device according to the present invention for achieving the above object is as follows.

A variable displacement hydraulic pump unit with a common drive shaft and multiple independent discharge ports,

A plurality of circuits respectively connecting a plurality of factories to the plurality of discharge ports;

Operating valves respectively provided in the plurality of circuits,

A pressure compensating valve provided in each of the plurality of circuits and set at the highest load pressure of the plurality of actuators; and a pressure compensating valve provided between the plurality of circuits and provided in the plurality of discharge ports. A pressure oil supply device comprising a plurality of circuits that are shut off when the pressures are equal, and a joining valve that communicates when a difference occurs in the pressures.

According to the first aspect, the pressure of each discharge port is independent and becomes a pressure corresponding to the external load of the actuator. When the load pressures of a plurality of actuators are different, the junction valve communicates. When the load compensating valve is set at the highest load pressure, the first actuating unit with a low load pressure and a large required flow rate and the load compensating valve are set at the highest load pressure. When simultaneously supplying hydraulic oil to the second actuator with a small required flow rate, the fluid supplied to the second Some will be supplied over the first night.

Therefore, since a part of the fluid supplied to the second actuator is only throttled when flowing through the junction valve, a loss when simultaneously operating a plurality of actuators is reduced.

In addition, when supplying pressure oil to the first actuator with a low load pressure and a small required flow rate and simultaneously supplying hydraulic oil to the second actuator with a high load pressure and a required flow rate of a dog, the merging valve is placed in the communication position and the shutoff position. They can only be switched alternately.

Therefore, a low-pressure fluid corresponding to the load pressure of the first actuator flows through the pressure compensating valve set at a high load pressure at the required flow rate, so that when operating multiple actuators simultaneously. Loss is reduced.

According to a second aspect of the present invention, in the above configuration,

The variable displacement hydraulic pump unit is configured such that a plurality of groups of a plurality of cylinder holes are concentrically arranged at positions near the outer circumference and the inner circumference of the cylinder block of the swash plate type hydraulic pump. A plurality of sets of high-pressure ports and low-pressure ports are formed circumferentially concentrically at positions close to the outer circumference and inner circumference of the valve plate. Device.

According to a third aspect of the present invention, in the above configuration,

The variable displacement hydraulic pump unit mechanically connects the drive shafts of the plurality of variable displacement hydraulic pumps and connects the swash plates of the plurality of hydraulic pumps so that the plurality of hydraulic pumps have the same capacity. This is a pressure oil supply device.

According to a fourth aspect of the present invention, in the above configuration, The merging valve includes a spring, a first pressure receiving unit connected to one of the plurality of circuits, and a second pressure receiving unit connected to the other of the plurality of circuits, and includes a force of the spring. A pressure oil supply device wherein the pressure oil supply device assumes a shut-off position, a first communication position by the pressure of the first pressure receiving portion, and a second communication position by the pressure of the second pressure receiving portion.

According to the fourth aspect, since the junction valve is directly switched by the pressure of the circuit, the switching operation of the junction valve is reliable, and the responsiveness is excellent.

According to a fifth aspect of the present invention, in the above configuration,

The merging valve has a spring and a solenoid, and becomes a shut-off position by the spring force, and a communication position by an external signal supplied to the solenoid.

First and second pressure sensors for respectively detecting one and the other pressures of the plurality of circuits,

A pressure oil supply device provided with a controller for supplying an external signal to the solenoid when there is a difference between pressures detected by the first and second pressure sensors.

According to the fifth aspect, by using the controller, the timing for switching the merging valve can be set arbitrarily. BRIEF DESCRIPTION OF THE FIGURES

The invention will be better understood from the following detailed description and the accompanying drawings illustrating an embodiment of the invention. The embodiments shown in the accompanying drawings are not intended to specify the invention, but merely to facilitate explanation and understanding. In the figure,

FIG. 1 is a hydraulic circuit diagram showing a conventional example.

FIG. 2 is a hydraulic circuit diagram showing a first embodiment of the pressure oil supply device according to the present invention.

FIG. 3 is a cross-sectional view of the double hydraulic pump according to the first embodiment.

FIG. 4 is a hydraulic circuit diagram showing a second embodiment of the pressure oil supply device according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a pressure oil supply device according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

First, a first embodiment will be described.

As shown in FIG. 2, the first and second circuits 11 and 12 connected to the first and second discharge ports 1Oa and 1Ob of the double hydraulic pump 10 are the first and second circuits, respectively. (2) Connected to the first and second factories (17, 18) via the control valves (13, 14) and the first and second pressure compensating valves (15, 16), respectively.

The first circuit 11 and the second circuit 12 are connected and disconnected by a merge valve 19. The merging valve 19 is held at the shut-off position a by the spring force. The connection position is switched between the first communication position b and the second communication position c by the pressure difference between the first pressure receiving portion 20 and the second pressure receiving portion 21. . The first pressure receiving section 20 is connected to the first circuit 11, and the second pressure receiving section 21 is connected to the second circuit 12. The higher of the load pressure of the first actuator 17 and the second 18 is detected by the shuttle valve 22 and the higher load is detected. The pressure acts on the first displacement control section 23 of the double hydraulic pump 10, and the higher pressure of the first and second discharge ports 10 a, 1 Ob is detected by the shuttle valve 24. The higher pressure acts on the second displacement control section 25 of the double hydraulic pump 10. As a result, the capacity of the double hydraulic pump 10 is controlled so that the differential pressure between the pump discharge pressure and the load pressure is kept constant. In addition, a third displacement control unit (not shown) is further provided in the double hydraulic pump 10 so that the pressures of the first and second discharge ports 10a and 1Ob are controlled by the second displacement control unit 25 and the third displacement control unit, respectively. The capacity of the double hydraulic pump 10 may be controlled so as to act on the capacity control unit so that the differential pressure between the pump discharge pressure and the load pressure becomes constant.

As shown in FIG. 3, the double hydraulic pump 10 includes a group including a plurality of first cylinder holes 31 at positions near the outer periphery and near the outer periphery of the cylinder block 30 of the swash plate type hydraulic pump. A group consisting of a plurality of second cylinder holes 32 is formed concentrically around each other, and the first high-pressure ports 34 and the first high-pressure ports 34 are located near the outer periphery and the inner periphery of the valve plate 33. A pair consisting of the low-pressure port 35 and a pair consisting of the second high-pressure port 36 and the second low-pressure port 37 are formed concentrically with each other to form an independent first hydraulic pump and a second hydraulic pump. The hydraulic pump is configured in the same block, and is configured as a variable displacement hydraulic pump unit having a common drive shaft and a plurality of discharge ports. And-the discharge part (first high pressure port 34) of the first hydraulic pump is the first discharge port 10a, and the discharge part (second high pressure port 36) of the second hydraulic pump is the second discharge port. The discharge port is 10b.

Next, the operation of the first embodiment will be described.

Negative pressurization at 1st factory overnight was low pressure and the required flow rate was large. When the negative pressure of 18 is high and the required flow rate is small.

Since the pressure P 1 in the first circuit 11 is lower than the pressure P 2 in the second circuit 12, the merging valve 19 is in the second communication position c, and a part of the fluid in the second circuit 12 is Flows into the first circuit 1 1. The load pressure of the second factory 18 acts on the capacity control unit 23, and the capacity of the double hydraulic pump 10 becomes a capacity corresponding to the load pressure of the second factory 18.

Thus, the pressure P 1 of the first circuit 11 is a low pressure commensurate with the magnitude of the external load of the actuator 17, and the pressure P 2 of the second circuit 12 is the pressure of the second actuator 18. The pressure is high corresponding to the magnitude of the external load, and a part of the fluid in the second circuit 12 is supplied to the first actuator 17 for support. Therefore, it is possible to supply a large amount of fluid to the first actuator 17 and operate it at high speed, and to operate the second actuator 18 at a higher pressure than the first actuator 17. Fluid can be supplied and operated with great power.

Although the opening area of the first pressure compensating valve 15 is small due to the load pressure on the high pressure side, the loss of the fluid is small because the pressure of the flowing fluid is low. It is throttled when flowing through the merging valve 19. Since the flow rate is small, the loss is small.

When the negative pressure of the 1st factory 17 is low pressure and the required flow rate is small, and when the negative pressure of the 2nd factory 18 is high pressure and the required flow rate is large.

As described above, the merging valve 19 is at the second communication position c, the first circuit 11 and the second circuit 12 are in communication, and the first pressure compensating valve 15 is throttled by the high-pressure side load pressure. Therefore, the pressure P 1 of the first circuit 11 and the pressure P 2 of the second circuit 12 are the same, and the junction valve 19 is at the shut-off position a. As a result, the pressure P 1 in the first circuit 11 is low and the pressure P 2 in the second circuit 12 is high. With the pressure, the merger valve 19 is again at the second communication position c. This operation is repeated.

FIG. 4 shows a second embodiment.

In this case, the drive shafts of the first hydraulic pump 40 and the second hydraulic pump 41 are mechanically connected, and the swash plate 42 of the first hydraulic pump 40 and the swash plate 4 of the second hydraulic pump 41 are connected. 3 are connected so that both pumps 40 and 41 have the same capacity, and are configured as a variable displacement hydraulic pump unit having a common drive shaft and a plurality of discharge ports ₍ No. 1 The output pressure of the shuttle valve 22 is supplied to the capacity control unit 44 of the hydraulic pump 40 and the capacity control unit 45 of the second hydraulic pump 41.

The first circuit 11 connected to the discharge port 40a of the first hydraulic pump 40 and the second circuit 12 connected to the discharge port 41a of the second hydraulic pump 41 connect the merging valve 19. Communication 'blocked. The merging valve 19 is held at the shut-off position a by the spring force, and becomes the communication position d when the solenoid 46 is energized. The pressure of the first circuit 11 is detected by a first pressure sensor 47, the pressure of the second circuit 12 is detected by a second pressure sensor 48, and input to the controller 49. The controller 49 energizes the solenoid 46 when there is a difference between the pressure detected by the first pressure sensor 47 and the pressure detected by the second pressure sensor 48.

Next, the operation of the second embodiment will be described.

If there is a difference between the pressure P i of the first circuit 11 and the pressure P 2 of the second circuit 12, the merging valve 19 becomes the communication position d, and the first and second hydraulic pumps 40, 4 Since the capacity of 1 is controlled to the same capacity, it operates in the same manner as in the first embodiment described above.

The merging valve 19 is made of pilot pressure oil supplied to the pressure receiving section. It may be the communication position d. In this case, the pilot pressure oil supply solenoid valve (not shown) is switched by the controller 49 to supply the pilot pressure oil to the pressure receiving portion of the merge valve 19.

Although the present invention has been described with reference to exemplary embodiments, it is to be noted that various modifications, omissions, and additions can be made to the disclosed embodiments without departing from the spirit and scope of the invention. It is obvious to those skilled in the art. Therefore, the present invention is not limited to the above embodiments, but should be understood as including the scope defined by the elements described in the claims and the equivalent scope thereof. Absent.

Claims

The scope of the claims

1. A variable displacement hydraulic pump unit having a plurality of independent discharge ports with a common drive shaft;

Operating valves respectively provided in the plurality of circuits,

A pressure compensating valve provided in each of the plurality of circuits and set at the highest load pressure of the plurality of actuators; and a plurality of discharge ports provided between the plurality of circuits. A pressure oil supply device, comprising: a plurality of circuits that are cut off when the pressures are equal to each other;

2. The variable displacement hydraulic pump unit has a plurality of groups of a plurality of cylinders and holes concentric with each other at positions closer to the outer circumference and inner circumference of the cylinder block of the swash plate type hydraulic pump. A plurality of sets each consisting of a high-pressure port and a low-pressure port are formed concentrically around the outer and inner circumferences of the valve plate. The pressurized oil supply device according to claim 1, which is provided.

3. The variable displacement hydraulic pump unit mechanically connects the drive shafts of the plurality of variable displacement hydraulic pumps and connects the swash plates of the plurality of hydraulic pumps so that the plurality of hydraulic pumps have the same capacity. The pressure oil supply device according to claim 1, wherein:

4. The junction valve connects to a spring and one of the plurality of circuits. A first pressure receiving portion, and a second pressure receiving portion connected to the other of the plurality of circuits, a breaking position by the force of the spring, a first communication position by the pressure of the first pressure receiving portion, The pressure oil supply device according to any one of claims 1 to 3, wherein the pressure oil supply device is set to a second communication position by a pressure of the second pressure receiving portion.

5. The merging valve has a spring and a solenoid, and assumes a shut-off position by the spring force and a communication position by an external signal supplied to the solenoid,

The pressure oil according to any one of claims 1 to 3, further comprising: a controller that supplies an external signal to the solenoid when there is a difference between the pressures detected by the first and second pressure sensors. Feeding device.