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Let's talk about its five most basic components: cylinder barrel and cylinder head, piston and piston rod, sealing device, buffer device and exhaust device.

The working principle of each cylinder is almost the same. Take a manual jack as an example, the jack is actually the simplest cylinder.  The hydraulic oil enters the oil cylinder through a one-way valve through a manual pressurizing rod (hydraulic manual pump). At this time, the hydraulic oil entering the oil cylinder cannot be reversed again due to a single valve, forcing the cylinder rod upward. Then the hydraulic oil continues to enter the hydraulic cylinder continuously during the work, thus rising continuously. When lowering, the hydraulic valve is opened to return the hydraulic oil to the oil tank. This is the simplest working principle. The others are all improved on this basis. The principle of the cylinder and the oil cylinder are basically the same.