KR20030058377A - apparatus for controlling hydraulic pumps in an excavator - Google Patents

Abstract

PURPOSE: A hydraulic pump controller of an excavator is provided to precisely control the flux of the pump. CONSTITUTION: A first detector(32-1) detects a high signal pressure during pilot signal pressures to be generated from remote control valves to control first operators. A second detector(32-2) detects a high signal pressure during pilot signal pressures to be generated from remote control valves to control second operators. A third detector(32-3) detects a high signal pressure during pilot signal pressures to be generated from remote control valves to control third operators. First, second and third transducers(34a,34b,34c) convert the detected signal pressures to electric signals. A control unit(35) feeds the highest signal value among the electric signals of the first and the second transducers to a pump regulator(3) of a first hydraulic pump(1) as a control signal. The control unit feeds the highest signal value among the electric signals of the second and the third transducers to a pump regulator(4) of a second hydraulic pump as a control signal. Thereby, the structure is simplified and a pump is controlled more precisely.

Description

Hydraulic pump control device for excavators {apparatus for controlling hydraulic pumps in an excavator}

The present invention relates to an apparatus for controlling a hydraulic pump of an excavator.

Conventional excavators usually use a variable displacement hydraulic pump as the main pump and control the discharge flow rate of the variable displacement hydraulic pump according to the increase or decrease of the negative-cone pressure caused by the change in the flow rate of the main pump passing through the center bypass line of the main control valve. "Negative Control" (hereinafter referred to simply as "negacon" control method) is adopted.

That is, the hydraulic control device of the conventional excavator as described above, as shown in Figure 1, the front working devices such as the boom cylinder 14, the arm cylinder 13, the bucket cylinder 15, or the traveling motor (11, 16) Alternatively, when the remote control valve 30 is operated to operate the swing motor 12, the corresponding control spool 21-28 of the main control valve 20 is the corresponding pilot signal pressure AL of the remote control valve 30. Since the oil is switched from the neutral position to the operating position, the hydraulic oil does not flow through the center bypass lines 7a and 7b so that the pressure (negacon pressure) of the negative cone valves 8a and 8b is lowered. Pi1 and Pi2 act on the pump regulators 3 and 4 to increase the discharge flow rates of the variable displacement hydraulic pumps 1 and 2.

As such, the conventional negative control system does not use a separate control device other than the negative cone valves 8a and 8b and controls the pump only by the bypass flow rate of the control valve, so the structure is simple and the control is easy. It is widely applied. However, such a negative control system has a disadvantage in that precise control is difficult and a so-called hunting phenomenon is caused when the bypass flow changes rapidly.

In order to solve the shortcomings of the negative control system, a method of generating a corresponding electronic control signal according to the operation of the remote control valve and directly controlling the flow rate of the pump as the electronic control signal has been proposed, but this is detected for each control signal of the remote control valve. There is a disadvantage that the price increases because a sensor is required.

Accordingly, an object of the present invention is to provide a hydraulic pump control device of an excavator that can control the flow rate of the pump with a simple structure.

1 is a schematic hydraulic circuit diagram of a conventional hydraulic pump control device of the negative control method;

2 is a schematic hydraulic circuit diagram of a first embodiment of a hydraulic pump control apparatus according to the present invention;

3 is a schematic hydraulic circuit diagram of a second embodiment of a hydraulic pump control apparatus according to the present invention;

4 is a schematic hydraulic circuit diagram of a third embodiment of a hydraulic pump control apparatus according to the present invention.

※ Explanation of code about main part of drawing ※

1: variable displacement first hydraulic pump 2: variable displacement second hydraulic pump

3,4: pump regulator

5: auxiliary hydraulic pump 11,16: left and right driving motor

12: slewing motor 13: arm cylinder

14: boom cylinder 15: bucket cylinder

16: space motor 20: control valve

21 ~ 28: Control spool 30: Remote control valve

30-1: Remote control valve for left driving control 30-2: Remote control valve for turning control

30-3: Remote control valve for arm control 30-4: Remote control valve for boom control

30-5: Remote control valve for bucket control 30-6: Space control remote control valve

31a, 31b, 31c, 31d, 31e, 31f: shuttle valve

A, B, C, D, E, F, G, H, I, J, K, L: Pilot Signal Pressure

32-1, 32-2, 32-3: first, second, third detection means 34a, 34b, 34c: first, second, third transducer

35: control unit 35a, 35b: fourth and fifth transducer

36a, 36b: switching valve 41: shuttle valve

42: shuttle valve 43, 44: pilot euro

The present invention for achieving the above object is a first variable displacement hydraulic pump and a second variable displacement hydraulic pump, an electronic proportional control valve type pump regulator for controlling the discharge flow rate of the first and second hydraulic pump, respectively, A plurality of first actuators which are operated by receiving only the hydraulic oil of the first hydraulic pump, a plurality of second actuators which are operated by receiving only the hydraulic oil of the second hydraulic pump, and the first and second hydraulic pumps. A plurality of third actuators operated by receiving the hydraulic oil, control spools for controlling the flow of the hydraulic oil supplied from the first and second hydraulic pumps, and the hydraulic pressure of the auxiliary hydraulic pump to reduce the pressure; An hydraulic pump control apparatus of an excavator having a remote control valve for generating a pilot signal for switching spools, the pilot signal generated from the remote control valves for controlling the first actuators. First detecting means for detecting a high signal pressure, second detecting means for detecting a high signal pressure among pilot signal pressures generated from remote control valves controlling the second actuators, and controlling the third actuators. Third detecting means for detecting a high signal pressure among pilot signal pressures generated from remote control valves, and first and second converting signal pressures detected by the first, second and third detecting means into electrical signals, respectively. Selects a signal value having a high value from among the three transducers and the electrical signals of the first and second transducers and applies the signal value as a control signal of a pump regulator of the first hydraulic pump, and the electrical signal of the second and third transducers. And a control unit for selecting a signal value having a high value among them and applying it as a control signal of a pump regulator of the second hydraulic pump.

In addition, the present invention, the first variable displacement hydraulic pump and the second variable displacement hydraulic pump, the hydraulic and electric combined pump regulator for controlling the discharge flow rate of the first and second hydraulic pump, respectively, the pressure of the first hydraulic pump A plurality of first actuators operated by receiving only oil, a plurality of second actuators operated by receiving only the hydraulic oil of the second hydraulic pump, and operated by receiving pressure oil jointly from the first and second hydraulic pumps A plurality of third actuators, control spools for controlling the flow of the pressurized oil supplied from the first and second hydraulic pumps, and the pressure oil of the auxiliary hydraulic pump to switch the control spools. A hydraulic pump control system of an excavator having remote control valves for generating a lot signal, wherein the pilot signal pressure generated from the remote control valves for controlling the first actuators is high. A first detecting means for detecting a pressure, a second detecting means for detecting a high signal pressure among pilot signal pressures generated from the remote control valves for controlling the second actuators, and a remote control for controlling the third actuators Third detection means for detecting a high signal pressure among pilot signal pressures generated from the valves, and first, second, and third transformers for converting the signal pressure detected from the first, second, and third detection means into electrical signals, respectively. A signal value having a high value among the electrical signals of the first and second transducers is selected and applied as a control signal of the pump regulator of the first hydraulic pump, and the value of the electrical signals of the second and third transducers. Selecting this high signal value and applying it as a control signal of the pump regulator of the second hydraulic pump is a shuttle valve for detecting a high signal pressure among the signal pressures detected from the first and second detection means. And a shuttle valve for detecting a high signal pressure among the signal pressures detected by the second and third detection means, and each pilot signal detected from the shuttle valve is a pump regulator and a pilot of the first and second hydraulic pumps, respectively. It is hydraulically connected via a flow path, but includes a switch valve for opening and closing the pilot flow path by receiving an electrical signal from the controller on the pilot flow path.

According to the present invention configured as described above, by operating the corresponding control valve for the front work device or traveling device, it detects this and applies an electrical signal or pilot hydraulic signal directly to the pump regulator of the hydraulic pump to increase the discharge flow rate of the pump. As it increases, it can be controlled quickly with a simple structure. In particular, by controlling the operation of the control valve and controlling the discharge flow rate of the pump by the electrical signal according to it can be more precise control than the negative control method.

Hereinafter, embodiments of the hydraulic pump control apparatus of an excavator according to the present invention will be described in detail according to the accompanying drawings.

Figure 2 shows a schematic hydraulic circuit diagram of a first embodiment of the present invention.

As shown in FIG. 2, the first embodiment of the present invention includes a first variable displacement hydraulic pump 1 and a second variable displacement hydraulic pump 2, wherein the first and second hydraulic pumps ( The discharge flow rates 1 and 2 are respectively controlled by the electromagnetic proportional control valve type pump regulators 3 and 4, respectively.

The first hydraulic pump 1 and the second hydraulic pump 2 supply hydraulic oil to a plurality of actuators. The plurality of actuators, like the left driving motor 11 or the turning motor 12, The first actuator that operates by receiving oil pressure from the hydraulic pump 1 alone, and like the space motor 16 or the bucket cylinder 15, operates by receiving oil pressure from the second hydraulic pump 2 alone. From the second actuator and the first hydraulic pump 1 and the second hydraulic pump 2, such as the boom cylinder 14 or the arm cylinder 13, which need to increase or increase the relative force for operation. It is classified as a third actuator which is jointly supplied with oil.

The pressure oil discharged from the first and second hydraulic pumps 1 and 2 is controlled in a flow direction in each control spool 21-28 of the control valve 20 to be supplied to the actuators. The remote control valve 30 includes a left driving control remote control valve 30-1, a turning control remote control valve 30-2, an arm control remote control valve 30-3, a boom control remote control valve 30-4. ), A bucket control remote control valve (30-5) and a space control remote control valve (30-6), each of these remote control valves to reduce the pressure of the auxiliary hydraulic pump (5) to control the spool for controlling the actuator Generate a pilot signal to switch between (21-28).

In addition, the present exemplary embodiment is configured to detect a high signal pressure among pilot signal pressures A, B, C, and D generated from the remote control valves 30-1 and 30-2 controlling the first actuators. The higher signal among pilot signal pressures (I, J, K, L) generated from the first detecting means (32-1) and the remote control valves (30-5, 30-6) for controlling the second actuators. Pilot signal pressures E, F, G, H generated from the second detecting means 32-2 for detecting the pressure, and the remote control valves 30-3, 30-4 for controlling the third actuators. And third detecting means 32-3 for detecting the high signal pressure.

The signal pressures detected by the first, second and third detection means 32-1, 32-2 and 32-3 are converted into electrical signals through the first, second and third transducers 34a, 34b and 34c, respectively. And input to the control unit 35. The controller 35 selects a signal value having a high value among electrical signals of the first and second transducers 34a and 34b and applies it as a control signal of the pump regulator 3 of the first hydraulic pump 1. In addition, a signal value having a high value is selected from the electrical signals of the second and third transducers 34b and 34c and applied as a control signal of the pump regulator 4 of the second hydraulic pump 2.

In the present embodiment, the first, second and third detection means 32-1, 32-2, and 32-3 are shuttle valves 31a for detecting a high signal pressure among pilot signal pressures output from the respective remote control valves. And 31b, 31c, 31d, 31e, and 31f, and the signal pressure detected from these shuttle valves 31a, 31b, 31c, 31d, 31e, and 31f to control the remote control valves corresponding to the first, second and third actuators. These are composed of shuttle valves 32a, 32b, and 32c which are combined by group to detect the high signal pressure again.

The first embodiment of the present invention configured as described above is for driving an actuator belonging to the first actuator or the second actuator, for example, the left driving motor 11, which is sufficient to receive pressure oil from one hydraulic pump for operation alone. When operating the remote control valve 30-1, the remote control valve 30-1 generates the pilot signal A or B and uses either of the left driving control spools 21 as the pilot signal. The oil pressure of the first hydraulic pump 1 is controlled by the left driving control spool 21 and is supplied to the left driving motor 11 to operate.

At the same time, the pilot signal A or B generated by the remote control valve 30-1 passes through two shuttle valves 31a and 32a of the first detection means 32-1, in order to pass through the first transducer ( Flows into 34a). The first transducer 34a converts the introduced pilot signal into an electrical signal and applies it to the controller 35. The controller 35 applies an electrical signal applied from the first transducer 34a to the first. It is applied to the pump regulator 3 of the hydraulic pump 1 to appropriately increase the discharge flow rate of the first hydraulic pump 1 to supply the required flow rate to the left running motor 11.

On the other hand, when driving the actuator belonging to the first actuator and the actuator belonging to the second actuator at the same time, the two hydraulic pumps (1, 2) should be controlled to operate. For example, in the so-called combined operation in which the boom rises while turning, the pressure oil of the first hydraulic pump 1 is supplied to the swing motor 12 and the pressure oil of the second hydraulic pump 2 is supplied to the boom cylinder 14. shall. For such a hybrid turning operation, when the swing control remote control valve 30-2 and the boom control remote control valve 30-4 are operated at the same time to generate the corresponding pilot signal E or F (G or H), The pilot signals control the corresponding control spools 22 and 26, respectively, to supply the hydraulic oil of the first hydraulic pump 1 to the turning motor 12, and at the same time, boom the hydraulic oil of the second hydraulic pump 2 to the boom cylinder 14. These actuators are operated by supplying

At the same time, the pivot control pilot signal E or F and the boom control pilot signal G or H pass through the shuttle valves 31b and 32a of the first detection means 32-1, respectively. ) Is converted into an electrical signal by the second transducer 34b via the shuttle valves 31d and 32b of the third detection means 32-3, and then applied to the control unit 35 to be controlled by the control unit 35. The discharge flow rates of the two hydraulic pumps 1 and 2 are increased by being applied to the first pump regulator 3 and the second pump regulator 4, respectively.

Figure 3 schematically shows a hydraulic circuit diagram of a second embodiment of the hydraulic pump control apparatus of the excavator according to the present invention. As shown in FIG. 3, the second embodiment of the present invention provides a high signal pressure among the signal pressures detected by the first and second detection means 32-1 and 32-2 in the first embodiment of the present invention. The shuttle valve 41 for detecting, the shuttle valve 42 for detecting a high signal pressure among the signal pressures detected by the second and third detection means 32-2, 32-3, and the shuttle valve 41, And fourth and fifth transducers 35a and 35b for converting the respective signal pressures detected from 42 into electrical signals, and the control unit 35 controls the first and second transducers 34a and 34b. The high signal value among the electrical signals and the high signal value among the electrical signals of the fourth transducer 35a are applied as a control signal of the pump regulator 3 of the first hydraulic pump 1, and the second and third transducers are applied. The high signal value among the electrical signals of the 34b and 34c and the high signal value of the electrical signal of the fifth transducer 35b are set by the pump regulator 4 of the second hydraulic pump 2. It is characterized in the configuration in which the signal applied to.

In the third embodiment of the present invention, as shown in the schematic hydraulic circuit diagram of FIG. 4, a high signal pressure is detected among the signal pressures detected by the first and second detection means 32-1 and 32-2. Shuttle valve 41, a shuttle valve 42 for detecting a high signal pressure among the signal pressures detected from the second and third detection means, and each pilot signal (detected from the shuttle valves 41, 42) Pi1 and Pi2 are hydraulically connected to the pump regulators 3 and 4 of the first and second hydraulic pumps 1 and 2 through pilot flow paths 43 and 44, respectively, and the pilot flow paths 43 and 44 ) Is composed of switching valves (36a, 36b) for opening and closing the pilot flow path (43, 44) by receiving an electrical signal from the control unit (35).

The controller 35 may be any one of a failure discrimination unit for determining whether the first, second, and third transducers 34a, 34b, and 34c are faulty, and the first and second transducers 34a and 34b. A switching signal is applied to the switching valve 36a when a failure occurs, and a switching signal is applied to the switching valve 36b when any one of the second and third transducers 34b and 34c fails. .

As described in detail above, the hydraulic pump control apparatus of the present invention uses the pilot signal generated to control the actuator directly as a control signal of the hydraulic pump or converts these pilot hydraulic signals into an electrical signal and converts the electrical signal into an electrical signal. By controlling the discharge flow rate of the hydraulic pump according to the value of, the structure is much simpler than the so-called negative cone control method that controls the pump discharge amount according to the flow rate passing through the bypass line of the conventional control valve, and makes the pump much more precise. There is an advantage to control.

Claims (6)

Electro-proportional control valve type pump regulator for controlling discharge flow rates of the first variable displacement hydraulic pump 1 and the second variable displacement hydraulic pump 2 and the first and second hydraulic pumps 1 and 2, respectively. 3 and 4, a plurality of first actuators operated by receiving only the hydraulic oil of the first hydraulic pump 1, and a plurality of second actuators operated by receiving only the hydraulic oil of the second hydraulic pump 2; Actuators, a plurality of third actuators which are operated by being fed with pressure oil from the first and second hydraulic pumps 1 and 2, and from the first and second hydraulic pumps 1 and 2 to the actuators. Control spools 21-28 for controlling the flow of pressure oil supplied, and a remote control valve for generating a pilot signal to switch the control spools 21-28 by reducing the pressure of the auxiliary hydraulic pump 5 In the excavator hydraulic pump control device provided with (30), First detecting means (32-1) for detecting a high signal pressure among pilot signal pressures generated from the remote control valves for controlling the first actuators; Second detecting means (32-2) for detecting a high signal pressure among pilot signal pressures generated from the remote control valves for controlling the second actuators; Third detecting means (32-3) for detecting a high signal pressure among pilot signal pressures generated from the remote control valves for controlling the third actuators; First, second and third transducers 34a, 34b and 34c for converting the signal pressures detected by the first, second and third detection means into electrical signals, respectively; A signal value having a high value is selected from the electrical signals of the first and second transducers 34a and 34b and applied as a control signal of the pump regulator 3 of the first hydraulic pump 1. Excavator characterized in that the control unit 35 is selected from the electrical signal of the transducer (34b, 34c) of the high value of the control unit 35 for applying as a control signal of the pump regulator 4 of the second hydraulic pump (2) Hydraulic pump control system. The shuttle valves 31a, 31b, 31c, 31d, 31e, and 31f of claim 1, wherein the first, second, and third detection means detect a high signal pressure among pilot signal pressures output from the respective remote control valves. ) And the shuttle valves 32a, 32b, and 32c which combine the signal pressures detected from these shuttle valves for each of the remote control valve groups corresponding to the first, second and third actuators, to detect the higher signal pressure again. Hydraulic pump control device of the excavator. The shuttle valve (41) according to claim 1, further comprising: a shuttle valve (41) for detecting a high signal pressure among the signal pressures detected by said first and second detection means; A shuttle valve 42 for detecting a high signal pressure among the signal pressures detected by the second and third detection means; And fourth and fifth transducers 35a and 35b for converting the signal pressures detected from the shuttle valves 41 and 42 into electrical signals. The controller 35 may generate a high signal value among the electrical signals of the first and second transducers 34a and 34b and a high signal value among the electrical signals of the fourth transducer 35a of the first hydraulic pump 1. It is applied as a control signal of the pump regulator 3, and a high signal value among the electrical signals of the second and third transducers 34b and 34c and a high signal value among the electrical signals of the fifth transducer 35b are second. Hydraulic pump control device of the excavator, characterized in that applied to the control signal of the pump regulator (4) of the hydraulic pump (2). Hydraulic and electric combined pump regulators 3 for controlling discharge flow rates of the first variable displacement hydraulic pump 1 and the second variable displacement hydraulic pump 2 and the first and second hydraulic pumps 1 and 2, respectively. And a plurality of first actuators operated by being supplied with only the hydraulic oil of the first hydraulic pump 1, and a plurality of second actuators being operated by being supplied with only the hydraulic oil of the second hydraulic pump 2. And a plurality of third actuators which are operated by receiving pressure oil jointly from the first and second hydraulic pumps 1 and 2 and supplied from the first and second hydraulic pumps 1 and 2 to the actuators. In the hydraulic pump control system of an excavator provided with control spools for controlling the flow of the pressure oil and a remote control valve for generating a pilot signal for reducing the pressure oil of the auxiliary hydraulic pump (5) to switch the control spools , First detecting means (32-1) for detecting a high signal pressure among pilot signal pressures generated from the remote control valves for controlling the first actuators; Second detecting means (32-2) for detecting a high signal pressure among pilot signal pressures generated from the remote control valves for controlling the second actuators; Third detecting means (32-3) for detecting a high signal pressure among pilot signal pressures generated from the remote control valves for controlling the third actuators; First, second and third transducers 34a, 34b and 34c for converting the signal pressures detected by the first, second and third detection means into electrical signals, respectively; A signal value having a high value is selected from the electrical signals of the first and second transducers 34a and 34b and applied as a control signal of the pump regulator 3 of the first hydraulic pump 1. The control unit 35 selects a signal value having a high value among electrical signals of the transducers 34b and 34c and applies it as a control signal of the pump regulator 4 of the second hydraulic pump 2. A shuttle valve 41 for detecting a high signal pressure among the signal pressures detected by the first and second detection means; A shuttle valve 42 for detecting a high signal pressure among the signal pressures detected by the second and third detection means; Each of the pilot signals Pi1 and Pi2 detected from the shuttle valves 41 and 42 is pump regulators 3 and 4 and pilot flow paths 43 and 44 of the first and second hydraulic pumps 1 and 2, respectively. It is hydraulically connected through the), consisting of a switching valve (36a, 36b) for opening and closing the pilot flow path (43,44) by receiving an electrical signal from the control unit 35 on the pilot flow path (43,44) Hydraulic pump control device of the excavator. 5. The control unit (35) of claim 4, wherein the control unit (35) includes a failure discrimination unit for determining whether the first, second, and third transducers (34a, 34b, 34c) are faulty, and the first and second transducers (34a, 34b). ), The switching signal is applied to the switching valve 36a when any one of them is broken, and the switching signal is applied to the switching valve 36b when any one of the second and third transducers 34b and 34c is broken. Hydraulic pump control device of the excavator. 5. The hydraulic pump control apparatus of claim 4, wherein the first, second and third detection means are shuttle valves.