A hydraulic press is a device that uses hydraulic transmission technology for pressure processing, and can be used to complete various forging and press forming processing. For example, forging of steel, forming of metal structural parts, restrictions on plastic products and rubber products, etc. Hydraulic press is one of the first machines to use hydraulic transmission. At present, hydraulic transmission has become the primary transmission form of pressure processing machinery. In the heavy machinery manufacturing, aviation industry, plastics and non-ferrous metal processing industries, hydraulic presses have become the primary equipment.
The hydraulic transmission system of a hydraulic press is mainly based on pressure conversion, with high system pressure, large flow, and high power. Therefore, special attention should be paid to improving the power utilization rate of the prime mover and avoiding shock and oscillation when the pressure is relieved to ensure safety and reliability.
According to the technical requirements of the hydraulic press, the main cylinder can complete the basic operation cycle of fast down, deceleration limit, pressure hold delay, pressure relief return, and stop (any position), and the pressure, speed and pressure hold time need to be adjustable. The ejection hydraulic cylinder is mainly used to eject the workpiece, and it needs to be able to achieve ejection, retreat, and stop actions. For example, when the sheet is stretched, auxiliary actions such as lifting, stopping and pressure return of the ejector hydraulic cylinder are required. Sometimes it is necessary to press the blank with a blank holder to avoid wrinkles around it.
The hydraulic press takes the maximum pressure (tonnage) that may be output by the primary actuator (master cylinder) in the main motion as the primary standard of the hydraulic press, and it has been serialized. The tonnage of the ejector cylinder is often 20%-50% of the tonnage of the main cylinder. The ejector cylinder of the extruder can be selected at the order of 10% of the primary tonnage. The tonnage of the blanking cylinder of the double-acting hydraulic stretching press is usually about 60% of the tonnage of the stretching cylinder.
The speed of the master cylinder is determined by the pressure processing technology. Usually in the hydraulic system directly supplied by the pump, the working stroke speed does not exceed 50mm/s, the fast forward speed does not exceed 300mm/s, and the hydraulic press retreats and fast forwards. The speed is flat.
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