Hydraulic system is a part of hydraulic machinery, the design of hydraulic transmission system should be synchronized with the overall design of the host. When designing, it is necessary to combine various transmission forms organically, and strive to design a hydraulic transmission system with reliable operation, simple structure, high efficiency, low cost, simple operation and convenient maintenance, and give full play to the advantages of hydraulic transmission.

1. Develop speed regulation scheme. After the hydraulic actuator is determined, the direction control is realized by the reversing valve or logic control unit, and the control of its movement direction and speed is the core problem of the hydraulic circuit. Generally, for high pressure and large flow hydraulic systems, most of the logic combination of cartridge valves and pilot control valves is used to achieve, for small and medium flow hydraulic systems, the required actions are mostly achieved through the organic combination of reversing valves.

2. Create a continuous action plan. Depending on the type of device, some of the host's actuators are random or artificial, and some run according to fixed procedures. The control mechanism of construction machinery is mostly manual, and it is generally controlled by manual multi-way reversing valve. When the working part moves to a certain position, the electric travel switch sends an electrical signal to the electromagnet to push the solenoid valve or directly press the travel valve to control the subsequent action. Stroke control is usually used for the sequential action of each mechanical actuator. The stroke switch is easy to install, and the stroke valve needs to be connected to the corresponding oil circuit, so it is only suitable for occasions where the pipeline connection is convenient. For example, when the hydraulic pump starts without load, the pump runs normally for a period of time, the delay relay sends an electrical signal, closes the unloading valve, and establishes the normal working pressure. Pressure control is used for extruding machines with hydraulic clamps, machine tools and other occasions, when a certain actuator completes a predetermined action, the pressure in the loop reaches a certain value, through the pressure relay to send an electrical signal or open the sequence valve to make the pressure oil pass, start the next action.

3, choose the hydraulic power source. The core of the hydraulic source is the hydraulic pump, and the working medium of the hydraulic system is completely provided by the hydraulic source. Usually, the oil supply of the hydraulic pump is greater than the oil supply of the system. In the absence of other auxiliary oil sources, the excess oil flows back to the tank through the relief valve, and the gas throttle control system uses a fixed pump to supply oil, which also plays the role of controlling and stabilizing the oil source pressure. Volume control system is mostly supplied by variable pump, system pressure is limited by safety valve. The oil supply of the hydraulic pump should match the flow required by the system as much as possible, in order to save energy and improve its efficiency. When the required flow rate of the system in each stage of the working cycle is small for a long time, an accumulator can be added as an auxiliary oil source, and when the amount of oil changes greatly, multi-pump oil supply or variable pump oil supply is generally used.

The general pump inlet is equipped with a coarse filter, the oil purification device is indispensable in the hydraulic source, and the oil entering the system is filtered again by the corresponding fine filter according to the requirements of the protected parts. Magnetic filters or other types of filters can be installed on the oil return channel, according to the requirements of the environment and temperature rise of the hydraulic equipment, in order to prevent impurities in the system from returning to the tank, heating and cooling measures should also be considered.