What is the working principle of piston hydraulic cylinder?

Piston hydraulic cylinders can be divided into single-rod and double-rod structures, with two fixed methods: cylinder body fixing and piston rod fixing. According to the action of hydraulic pressure, there are single-acting and double-acting types. In a single-acting hydraulic cylinder, the pressure oil is supplied to only one chamber of the cylinder, and the cylinder achieves one-way movement by hydraulic pressure. The reverse movement is achieved by external forces such as spring force, self-weight, or external load. In a double-acting hydraulic cylinder, the piston's movement in both directions is achieved by alternating oil inlet to the two chambers, relying on the action of hydraulic pressure.

It has only one piston rod on one side of the piston, so the effective working area of the two chambers is different. When the oil supply is the same, the piston's movement speed is different depending on the chamber being supplied with oil. When the load force to be overcome is the same, different oil inlets to the chambers require different oil supply pressures, or in other words, the load force that the hydraulic cylinder of a sanitation garbage truck can overcome in two directions is different after the system pressure is adjusted.

One more point: Hydraulic transmission principle - using oil as the working medium to transmit motion by changing the sealed volume and transmitting power through internal oil pressure.

1. Power section - converts the mechanical energy of the prime mover into hydraulic pressure energy (hydraulic energy). For example, hydraulic pumps.

2. Execution section - converts the hydraulic pressure energy input by the hydraulic pump into mechanical energy that drives the working mechanism. For example, hydraulic cylinders, hydraulic motors.

3. Control section - used to control and adjust the pressure, flow rate, and flow direction of the oil. For example, pressure control valves, flow control valves, and directional control valves.

4. Auxiliary section - connects the previous three sections together to form a system, and performs functions such as oil storage, filtration, measurement, and sealing. For example, pipelines and fittings, oil tanks, filters, accumulators, seals, and control instruments, etc.