KR950014497A - Automatic sequential boosting system of hydraulic circuit - Google Patents

Abstract

According to the present invention, when the overload is activated, the relief is first released to the first set pressure of the two-stage safety valve, after which the discharge oil of the hydraulic pump is reduced after a predetermined time and then released to the second set pressure that is higher than the first set pressure. By reducing the peak pressure at the time of relief to improve hydraulic equipment durability, the controller also inputs the first set pressure signal from the discharge pressure detector and then discharges the hydraulic pump after a predetermined time. At a reduced time point, the second set pressure signal higher than the first set pressure is output to the set pressure converter to control the set pressure of the safety valve to be sequentially raised.

Description

Automatic sequential boosting system of hydraulic circuit

Since this is an open matter, no full text was included.

1 is a diagram showing a control circuit of the hydraulic excavator in the embodiment of the present invention.

FIG. 2 is a diagram showing details of the controller in the control circuit of FIG.

3 is a diagram showing the relationship between the discharge pressure P of the hydraulic pump and the pump capacity in the control circuit of FIG. 4 is a diagram showing changes over time of the discharge pressure P of the hydraulic pump in FIG.

Claims (8)

A safety valve for setting the maximum pressure of the hydraulic circuit in multiple stages, a relief operating time detector for detecting a time when the safety valve is continuously released at a predetermined set pressure, and the relief operating time detector is used for the low pressure side. And a set pressure switching means for detecting a predetermined time relief at a set pressure, and changing the set pressure to a set pressure on the high pressure side. A variable displacement hydraulic pump 2 for driving an actuator, a capacity control device 8 of the hydraulic pump, a control pressure source of the capacity control device, a discharge pressure detector 18 of the hydraulic pump described above, and the discharge pressure The pressure of the above-mentioned control pressure source is reduced and supplied to the above capacity control device 8 so that the forging reduction function in which the amount of the hydraulic pump is basically determined with respect to the discharge pressure of the hydraulic pump detected by the detector 18 is reduced. A hop water torque manufacturing valve 10, a two-stage safety valve 5 for setting the maximum pressure of the hydraulic pump in two stages, a set pressure converter of the two-stage safety valve 5, and a set pressure converter. In the control apparatus of the hydraulic circuit which consists of a controller 19 etc. which control the switching signal to supply, the said controller 19 inputs a 1st set pressure signal from the discharge pressure detector 18, and then after a predetermined time. A second higher than the first set pressure to the set pressure transducer; An automatic sequential boosting system of a hydraulic circuit, characterized by outputting a set pressure setting signal. A variable displacement hydraulic pump 2 for driving an actuator, a capacity control device 8 of the hydraulic pump, a control pressure source of the capacity control device, a discharge pressure detector 18 of the hydraulic pump described above, and a predetermined absorption In the torque signal, the first hop number torque curve in which the capacity of the hydraulic pump is essentially determined with respect to the discharge pressure of the hydraulic pump detected by the discharge pressure detector 18 becomes the monotonic reduction function, and the predetermined hop number is By changing the torque signal, the second absorption torque curve, which is basically determined at a capacity smaller than the capacity in the first absorption torque curve described above, with respect to the same discharge pressure of the hydraulic pump, becomes a monotonic reduction function. An absorption torque control valve 10 for reducing the source pressure of the control pressure source and supplying it to the capacity control device, and a two-stage safety valve 5 for setting the maximum set pressure of the hydraulic pump in two stages And a hydraulic pressure comprising a set pressure converter of the two-stage safety valve and a converter 19 for controlling a conversion signal supplied to the solenoid 10a of the hop water torque control valve 10 and the set pressure converter of the two-stage safety valve. In the controller of the circuit, when the controller receives a pressure signal of less than the first maximum set pressure from the discharge pressure detector 18, the controller returns a specified hop torque signal that draws the first absorption torque curve. When the pressure signal of the first setting '17 is inputted to the reduced absorption torque signal that draws the hop number torque curve, the controller 19 sets a higher pressure than the first set pressure to the set pressure converter after a predetermined time. 2. An automatic sequential boosting system of a hydraulic circuit, characterized by outputting a set pressure setting signal. 4. The controller according to claim 3, wherein the release switch for releasing the reduced hop torque signal to return to the specified absorption torque signal and the release signal from the release switch are input by the controller. An automatic sequential boosting system of a hydraulic circuit, characterized in that to release a reduced absorption torque signal to a solenoid (10a) of one hop torque control valve (10) to output a specified absorption torque signal. The automatic sequential boosting system of a hydraulic circuit according to claim 2, wherein the forging reduction force is a product of a capacity of the hydraulic pump and a discharge pressure of the hydraulic pump. The automatic booster boosting system of a hydraulic circuit according to claim 2, wherein the two forging reduction functions are a product of a capacity of a hydraulic pump and a discharge pressure of the hydraulic pump. The pressure of the above-mentioned control pressure source is reduced so that the horsepower solid state in which the discharge flow rate of the hydraulic pump is essentially determined with respect to the discharge pressure of the hydraulic pump detected by the discharge pressure detector is reduced. An automatic sequential boosting system of the hydraulic circuit, characterized in that the supply to the capacity control device (8). 4. A predetermined hop number torque signal supplied to the solenoid 10a of the hop number torque control valve 10 of the hydraulic pump according to claim 3, wherein the discharge flow rate is essentially determined with respect to the discharge pressure of the hydraulic pump. The first horsepower curve becomes a forging reduction function, and the discharge flow is lowered by a predetermined amount smaller than the discharge flow rate in the first horsepower curve described above for the same discharge pressure of the hydraulic pump by changing the predetermined hop number torque signal. In the main circuit of the hydraulic circuit, characterized in that the source pressure of the control pressure source is reduced and supplied to the capacity control device (8) so that the second horsepower curve which is basically determined is the monotonic reduction function. ※ Note: The disclosure is based on the initial application.