Working principle of hydraulic system

The characteristics of hydraulic transmission systems are high pressure, high power, and suitable for high-speed and heavy-duty applications. In some precision machinery and instruments, hydraulic transmission plays a crucial role. The hydraulic transmission system consists of three major parts: liquid, hydraulic pump, and actuator. The hydraulic circuit mainly consists of oil tank, overflow valve, one-way throttle valve, safety valve, etc.

Liquid flow mode: The liquid enters the cylinder through a one-way valve from the oil tank, and then returns to the tank through a one-way valve. The oil returns to the tank through an overflow valve, and the system pressure is reduced through a safety valve. Then, the system pressure is reduced to the working pressure through a throttle valve. The hydraulic pump sends the high-pressure oil that has been throttled into the working chamber of the actuator, causing the actuator to move under the pressure difference. The actuator drives the motor to rotate and drives the machinery to do work.

Liquid flow state: The system is filled with high-pressure oil. After inputting a certain amount of hydraulic oil into the actuator, the oil begins to flow. When the oil cylinder piston moves downwards, the oil flows into the oil tank under the action of gravity; When the piston moves upwards, the oil is sucked out of the tank. During the upward and downward movement of the piston, the hydraulic oil is continuously heated and cooled to a certain temperature; When the temperature drops to a certain level, the hydraulic oil is pumped back to the oil tank; When the temperature rises to a certain level, hydraulic oil is pumped to another working chamber. In this cyclic process, the oil is heated, cooled, and repeatedly recycled. Due to the fact that this cycle process relies on hydraulic oil to transmit energy, it is called hydraulic transmission.