Precision pressure control system and hydraulic machining method of servo pump control hydraulic machine

Abstract

The invention relates to a precision pressure control system and a hydraulic machining method of a servo pump control hydraulic machine. The hydraulic machine comprises a medium-flow servo pump and alarge-flow servo pump driven by a servo motor, outlet pipelines of two pumps are connected with a main cylinder upper cavity oil way through a seventh dynamic valve, and the main cylinder upper cavityoil way is further connected with an oil tank through a fourth dynamic valve and a proportional valve; a main cylinder lower cavity pipeline is connected with an outlet of a ninth cartridge valve, aninlet of the ninth cartridge valve is connected with the oil tank through a fifth cartridge valve and an eighth cartridge valve, the fifth cartridge valve supplies supporting force during deceleration and pressurization through an overflow valve, and the eighth cartridge valve is turned on during the return stroke. In hydraulic machining, each working cycle comprises the following actions of automatic pressure compensation for an energy accumulator, pressure supplementation stopping for the energy accumulator, rapid descending of a sliding block, deceleration pressurizing of the sliding block, pressure maintaining of the sliding block, pressure relief of the sliding block, and return and stopping of the sliding block. The servo driver is switched in two modes of flow control and PID regulation control, stable pressurization of the sliding block is achieved, the phenomenon that a part deforms due to pressurization overshoot is avoided, and pressure relief is stable.

Description

technical field [0001] The invention relates to a hydraulic machine, in particular to a precision pressure control system of a servo pump-controlled hydraulic machine. The invention also relates to a hydraulic processing method of a hydraulic machine, which belongs to the technical field of machine tool control systems. Background technique [0002] In the normal process mode of the hydraulic press, there are two control methods: fixed range and constant pressure. The fixed range state is controlled by the stop position of the slider, while the constant pressure state is the pressure value generated after the slider drives the upper mold and the lower mold to completely close. However, in the state of constant pressure, the rapid downward movement of the slider and the transition to the working movement are controlled by the position signal, so in the constant pressure mode, the position feedback is used to control at first, and then switch when the actuator is in contact wit...

AI Technical Summary

Problems solved by technology

When using servo pump control, there are both pump port pressure sensor and master cylinder upper chamber pressure sensor. The sensor uses voltage signal which is not only susceptible to interference but also difficult to troubleshoot.

Under high-frequency operation, the impact noise is louder when the pressure is released, which may easily cause loosening of the fixing parts

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