In the four-column hydraulic machine speed change system, the common speed control control loops include the stepless speed control loop and the stepped speed control loop. Among them, the stepless speed control loop can be divided into a saving speed control loop and a stepless speed control loop according to the different speed change methods. Capacity variable speed control loop.
Secondly, the system pressure cannot be higher than the pump pressure, unless it is a four-column hydraulic machine with a pressure pump. The actual working pressure of the pump depends on the load size, which is automatically formed rather than adjusted. It is normal for a four-column hydraulic machine to give a working pressure When working under high pressure, reduce the pressure of the speed control valve, close the pump inlet and outlet of the four-column hydraulic machine, the relief valve, the hydraulic reversing valve, etc., adjust the speed control valve, and the pump inlet and outlet pressure rises until it reaches the required value.
The hydraulic control system of a four-column hydraulic press consists of a driving force organization, a control device, an actuator, an auxiliary mechanism and a medium. Generally, a gasoline pump is used as the driving mechanism, and an accumulator gasoline pump is generally used as the driving mechanism. Use one gasoline pump or several gasoline pumps to meet the relative speed requirements of the actuator. Low voltage (steam pressure below 2.5MP) uses a gear pump; high voltage (steam pressure below 6.3MP) uses an axial piston pump; high pressure (steam pressure below 32.0MP) uses a hydraulic piston pump. Pressure processing and molding of various plastic materials, such as stainless steel plate extrusion molding, bending, stretching, cold extrusion molding of metal parts, and can also be used to suppress powder products, grinding wheels, bakelite powder, and epoxy resin thermosetting plastic products.
