JP3910137B2 - Hydraulic motor drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a hydraulic motor driving apparatus that drives a plurality of hydraulic motors in a composite manner.
[0002]
[Prior art]
An example of a conventional hydraulic motor driving device is shown in FIG. Explaining this, pressurized hydraulic fluid discharged from a single pump 3 is supplied to a plurality of motors 1, 2,... Via flow control valves 11, 12,. The The flow rate control valves 11, 12,... Adjust the flow rate of the hydraulic fluid supplied to the motors 1, 2,. The pressure compensation valves 21, 22,... Keep the differential pressure across the flow control valves 11, 12,.
[0003]
The pump 3 includes a variable capacity mechanism 4 that makes the displacement volume variable, and a pump regulator 5 that adjusts the pressure for driving the variable capacity mechanism 4. The pump regulator 5 is guided by selecting the maximum load pressure among the load pressures of the motors 1, 2,... By the high pressure selection valves 31, 32,. Load sensing control for changing the displacement volume of the pump 3 is performed. Thereby, the amount of surplus hydraulic fluid discharged from the pump 3 is suppressed, and energy consumption is reduced.
[0004]
Further, the hydraulic motor driving device of the hydraulic excavator disclosed in Patent Document 1 has a configuration that suppresses the occurrence of saturation in load sensing control.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 4-31628 [0006]
[Problems to be solved by the invention]
However, in the conventional hydraulic motor driving apparatus shown in FIG. 2, the motor 1, 2... Has a lower load pressure due to the pump discharge pressure based on the highest load pressure. In order to drive the motor 1, 2,... Having a low load pressure, there was an energy loss that was discarded as heat generation in the pressure compensation valves 21, 22,.
[0007]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a hydraulic motor driving device that reduces energy loss that occurs when a plurality of hydraulic motors are driven in combination.
[0008]
[Means for Solving the Problems]
The first invention provides a supply passage for supplying hydraulic fluid discharged from the pump to the first and second motors, and first and second flow rates for adjusting the amounts of hydraulic fluid supplied to the first and second motors, respectively. The present invention is applied to a hydraulic motor driving device including a control valve.
[0009]
Then, the high pressure selection means for selecting and guiding a higher load pressure from the first and second motors, and adjusting the displacement of the pump according to the differential pressure between the selected high load pressure and the pump discharge pressure. A pump regulator and first and second motor regulators that adjust the displacement of the first and second motors according to the differential pressure between the selected high load pressure and the load pressures of the first and second motors, respectively. It was characterized by the provision.
[0010]
Operation and effect of the invention
According to the first invention, the pump regulator performs load sensing control for changing the discharge flow rate of the pump in accordance with the selected high load pressure. As a result, the amount of surplus hydraulic fluid discharged from the pump is suppressed and energy consumption is reduced.
[0011]
The first and second regulators adjust the displacement volume of the first and second motors according to changes in the differential pressure between the selected high load pressure and their own load pressure, so that the respective drive torques are substantially equal. Perform load sensing control.
[0012]
For example, when the load pressure of the first motor is higher than that of the second regulator, the displacement volume of the first motor is adjusted to be large via the first motor regulator, and the load pressure of the first motor is reduced. On the other hand, the displacement volume of the second motor is adjusted via the second motor regulator so that the displacement volume of the second motor is reduced so that the differential pressure between the two load pressures is reduced.
[0013]
As a result, the pressure compensation element provided with the flow rate control valve in the conventional apparatus can be eliminated, and the energy loss discarded as heat generation in the pressure compensation element can be reduced.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0015]
The hydraulic motor driving device shown in FIG. 1 is used to drive an air conditioner system mounted on a vehicle, for example, and drives a hydraulic pump 3 driven by an engine, a compressor that compresses refrigerant, a blower fan, and the like. To a plurality of hydraulic motors 1, 2,..., Supply passages 13, 14,... For supplying hydraulic fluid discharged from the pump 3 to the motors 1, 2,. The flow control valves 11, 12,... For adjusting the amount of hydraulic fluid supplied are provided.
[0016]
The pump 3 is constituted by a variable displacement piston pump whose displacement is variable according to the tilt angle of the swash plate, and includes a pump regulator 5 that changes the tilt angle of the swash plate via the variable capacity mechanism 4.
[0017]
The pump regulator 5 guides the discharge pressure of the pump 3 through the pilot pressure passage 6, and also selects each high-pressure selection valve (high-pressure selection means) from among the load pressures of the motors 1, 2,. ) 31, 32,... Are selected and guided, and load sensing control is performed in which the displacement volume of the pump 3 is changed according to the differential pressure between the maximum load pressure and the discharge pressure of the pump 3.
[0018]
Each of the motors 1, 2,... Is constituted by a variable displacement type piston motor whose displacement is variable according to the inclination angle of the swash plate, and the motor that changes the inclination angle of the swash plate via the variable capacity mechanisms 41, 42,. Regulators 51, 52,...
[0019]
In the motor regulators 51, 52,..., The load pressures of the motors 1, 2,... Are guided through the pilot pressure passages 8, 9,. The highest load pressure is selected and guided by the high pressure selection valves 31, 32,..., And the motors 1, 2,... Are displaced according to the differential pressure between the maximum load pressure and the own load pressure. Perform load sensing control to change volume.
[0020]
Each of the flow control valves 11, 12,... Adjusts the flow rate of the hydraulic fluid supplied to each of the motors 1, 2,. The controller 10 reads the rotational speeds of the motors 1, 2,... Detected by a sensor (not shown), and sets the opening degree of the flow control valves 11, 12, ... so that the rotational speeds of the motors 1, 2,. Control.
[0021]
Next, the operation will be described.
[0022]
The pressurized hydraulic fluid discharged from the single pump 3 is supplied to the motors 1, 2,... Via the flow control valves 11, 12,.
[0023]
The pump regulator 5 changes the discharge flow rate of the pump 3 according to the maximum load pressure of each motor 1, 2,..., And adjusts the discharge pressure of the pump 3 to be higher than the maximum load pressure by a certain differential pressure. Performs sensing (load sensitive) control. Thereby, the amount of surplus hydraulic fluid discharged from the pump 3 is suppressed, and energy consumption is reduced.
[0024]
The motor regulators 51, 52,... Adjust the displacement volumes of the motors 1, 2,... According to the difference in pressure between the maximum load pressure of the motors 1, 2,. Perform load sensing control to equalize the load pressure. For example, when the load pressure of the motor 1 becomes the highest, the displacement volume of the motor 1 is adjusted to the maximum via the motor regulator 51, and the load pressure of the motor 1 is reduced. At this time, the displacement volume of the other motors 2,... Is reduced so that the differential pressure between the load pressure of the motor 1 and each load pressure is reduced via the motor regulators 52,. As a result, each load pressure increases.
[0025]
As a result, the pressure compensation element provided with the flow control valve in the conventional device can be eliminated, and the energy loss discarded as heat generation in the pressure compensation element can be reduced.
[0026]
The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.
[Brief description of the drawings]
FIG. 1 is a hydraulic circuit diagram of a hydraulic motor driving apparatus showing an embodiment of the present invention.
FIG. 2 is a hydraulic circuit diagram of a hydraulic motor driving apparatus showing a conventional example.
[Explanation of symbols]
1, 2 Motor 3 Pump 5 Regulator 11, 12 Flow rate control valve 31, 32 High pressure selection valve (high pressure selection means)
41, 42 Variable capacity mechanism 51, 52 Regulator

Claims (1)

A fluid comprising a supply passage for supplying hydraulic fluid discharged from the pump to the first and second motors, and first and second flow control valves for adjusting the amounts of hydraulic fluid supplied to the first and second motors, respectively. In the pressure motor drive device,
High pressure selection means for selecting and guiding a higher load pressure from the first and second motors, and adjusting the displacement volume of the pump according to the differential pressure between the selected high load pressure and the pump discharge pressure A pump regulator and first and second motor regulators that adjust the displacement of the first and second motors according to the differential pressure between the selected high load pressure and the load pressures of the first and second motors, respectively. A hydraulic motor driving device comprising:

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