Hydraulic overload protecting device and pressing machine with hydraulic overload protecting device

Abstract

The invention discloses a hydraulic overload protecting device of a gas spring energy accumulator with a manual oil pumping function. The hydraulic overload protecting device and a slide block hydraulic cushion form a closed loop. A plunger is driven by a pneumatic proportional pressurizing piston to extrude oil liquid in a system, so that the pressure of the oil liquid of the slide block hydraulic cushion reaches the required working pressure value from the initial pressure. When a pressing machine is overloaded, a pressure indicator transmits a signal to enable an electromagnetic valve to act to switch an air channel, the proportional pressurizing piston drives the plunger to quickly move to restore, a pressurizing cavity is communicated with a pressure-releasing cavity, and the oil liquid in the slide block hydraulic cushion is quickly released to the gas spring energy accumulator. After a pressing machine slide block is overloaded to surpass a bottom dead centre, the oil liquid of the gas spring energy accumulator can be automatically supplemented back into the slide block hydraulic cushion, and the initial working state is quickly restored. Once an overload failure is cleared, the pressing machine can immediately normally work again according to a program. The pressing machine with the hydraulic overload protecting device is reliable in work and long in maintenance-free period.

Description

technical field [0001] The invention relates to overload protection of a press, in particular to a hydraulic overload protection device for a mechanical press. The invention also relates to a press equipped with such a device. Background technique [0002] A press is a metal forming machine. In actual use, due to various reasons, the working pressure of the slider will exceed the allowable range. Such as: Improper selection of presses, inaccurate mold adjustment, overlapping blanks, increased material strength, blunt die blades, and foreign objects falling into the die cavity, etc. This often results in equipment damage or personal injury. [0003] In order to solve this problem, various forms of overload protection devices are commonly used in presses. Take the common hydraulic overload protection device with air pressure as the power source in my country's press industry as an example. It is mainly composed of pneumatic oil pressure booster pump, overload pressure unloa...

AI Technical Summary

Problems solved by technology

[0005] (1) The pneumatic oil pressure booster pump moves frequently and is easily damaged;

[0006] (2) The time interval from the occurrence of overload to the return of the press to normal work is long, and the work efficiency is low;

[0007] (3) Difficult maintenance and high cost, it is difficult to be widely used by small and medium-sized presses with large quantities and wide areas

[0010] (1) Compressed air is passed inside the closed oil tank, which makes the air easily mixed into the hydraulic oil and reduces the elastic modulus of the oil, making the oil-air proportional valve work unstable and reducing the rigidity of the press

[0011] (2) Only use the digital display pressure gauge to output the overload alarm signal to control the solenoid valve to release the pressure of the hydraulic oil. When the digital display pressure gauge fails or has a large error, the overload hydraulic oil has no pressure relief channel, and the press has potential safety hazards

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