The main difference between servo hydraulic press and ordinary hydraulic press is the difference of power source. One is to use the hydraulic oil cylinder in the hydraulic system to generate pressure; the other is to use compressed air as the power source and use the pneumatic cylinder to execute the device, which is the essential difference between them.
The development of servo hydraulic press is greatly influenced by servo motor. At present, the hydraulic press driven by servo motor is mainly some small tonnage presses. In order to break through the limitation of servo motor, hybrid drive mode is a direction of the development of press at present. The structure of the hybrid driven press adopts differential wheel to realize the mixed input of ordinary motor and servo motor, and adopts two degree of freedom bar system to realize the hybrid closed double point press. Its characteristics are as follows:
(1) It has high versatility, flexibility and intelligence.
Because of its servo function, the slider motion curve is no longer just a sine curve, but any curve that can be optimized according to the process requirements.
(2) High precision.
Due to the use of linear grating ruler to detect the position of the slider, the slider has the whole working process of the press; high motion control accuracy, especially near the bottom dead center, can ensure the accuracy of the slider changes within ± 0.01mm; thus, the accuracy of the press's closing height in the production process is stable, the burr of the product is suppressed, and the defective products are prevented.
(3) High productivity.
Because the servo hydraulic press retains the advantages of crank press, especially the productivity is much higher than hydraulic press, it reflects the "processing quality of hydraulic press and the production efficiency of mechanical press". In addition, the crank press driven by servo motor can also adjust the stroke of slide block according to the different workpiece. In one working cycle, it is not necessary to complete 360 degree rotation, but only swing at a certain angle to complete the stamping work, which further shortens the cycle time. It reduces the unnecessary journey to the maximum extent and greatly improves the productivity.
Compared with the mechanical press driven by conventional AC asynchronous motor.