Hydraulic control system and method for passive type four-corner-leveling hydraulic press

Abstract

The invention discloses a hydraulic control system and method for a passive type four-corner-leveling hydraulic press. The hydraulic control system is provided with two oil sources, namely the high-pressure oil source P1 and the low-pressure oil source P2. The high-pressure oil source P1 can be provided by an energy accumulator control hydraulic system and provides a power source for pre-acceleration motion and mould micro-opening control; the low-pressure oil source P2 can be provided by a circulating cooling pump in a pump station and is manly used for supplementing oil in the upper cavity of a piston hydraulic cylinder in the leveling control process to prevent a rod cavity from being sucked empty. Furthermore, a high-frequency-response proportion servo valve with a closed position loop is adopted as a synchronous control element of a leveling hydraulic cylinder. The hydraulic control system is low in manufacturing cost, strong in anti-pollution capacity and capable of achieving automatic control easily, thereby being applicable to occasions with high power and high synchronous accuracy. Moreover, according to the control method, it is unnecessary that a certain leveling hydraulic cylinder is selected as a driving cylinder, and leveling errors caused by selecting the driving cylinder by experience are eliminated. In addition, the rapid descending / returning speed of the passive type four-corner-leveling hydraulic press can reach 1200mm / s, and the minimum leveling accuracy can reach 0.02mm.

Description

technical field [0001] The invention relates to a hydraulic control system, in particular to a hydraulic control system and a control method of a passive four-corner leveling hydraulic machine. Background technique [0002] The biggest feature of the fast and high-precision hydraulic press is its fast working speed (fast down / return speed up to 1200mm / s) and high leveling accuracy (the minimum leveling precision can reach 0.02mm). In order to meet this characteristic, this type of hydraulic machine uses a piston accumulator to control the hydraulic system. Generally speaking, the piston accumulator is used to quickly release the high-pressure oil that has been stored in advance, and then the high-pressure oil is pumped through the large-diameter proportional servo valve. Closed-loop adjustment of pressure, flow, etc., to complete a series of molding process actions such as "rapid downward, pre-pressurization, pressurization, pressure holding, pressure relief, demoulding, and...

AI Technical Summary

Problems solved by technology

However, the passive four-corner leveling system using the master-slave control method has certain problems in the selection of the active cylinder.

Generally, a certain leveling hydraulic cylinder is directly used as the active cylinder. During the descending process of the press, since the four leveling hydraulic cylinders may be in the pressing process, the force of each cylinder is different, and the selection of the active cylinder is only based on experience. , there will also be a large error, which affects the parallel accuracy of the pressing process, thereby affecting the production

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