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The Structure and the Components of the Hydraulic Cylinder

The hydraulic cylinder is a hydraulic actuator that converts hydraulic energy into mechanical energy and performs linear reciprocating motion (or swing motion). It has simple structure and reliable work. When it is used to achieve reciprocating motion, the deceleration device can be eliminated, and there is no transmission gap, and the motion is stable. Therefore, it is widely used in various mechanical hydraulic systems. Next, I will introduce the structure and cylinder assembly of the hydraulic cylinder.


1. The structure of hydraulic cylinder


The hydraulic cylinder is usually composed of the main parts of the back end cover, cylinder barrel, piston rod, piston assembly, front end cover, etc.; in order to prevent oil leakage to the outside of the hydraulic cylinder or from the high pressure cavity to the low pressure cavity, the cylinder and the end cover, piston Sealing devices are installed between the piston rod, the piston and the cylinder, the piston rod and the front end cover. On the outside of the front end cover, there is also a dustproof device; in order to prevent the piston from hitting the cylinder head when it quickly retracts to the stroke end, the hydraulic cylinder end The department is also equipped with a buffer device; sometimes an exhaust device is required.


2. Hydraulic cylinder components


The sealed cavity formed by the hydraulic cylinder components and the piston assembly bears the action of oil pressure. Therefore, the hydraulic cylinder components must have sufficient strength, high surface accuracy and reliable sealing.


(1) Flange type connection, simple structure, convenient processing, reliable connection, but requires sufficient wall thickness at the end of the cylinder barrel to install bolts or screw in screws. It is a commonly used connection form.


(2) Half-ring connection is divided into outer half-ring connection and inner half-ring connection. The half-ring connection has good manufacturability, reliable connection and compact structure, but it weakens the strength of the cylinder. Half-ring connection applications are very common, often used in the connection of seamless steel tube cylinders and end covers.


(3) Threaded connection, there are two kinds of external thread connection and internal thread connection. It is characterized by small size, light weight and compact structure, but the structure of the cylinder barrel end is complicated. This connection form is generally used for small size, lightweight occasions.


(4) Tie rod type connection, simple structure, good manufacturability, and strong versatility, but the volume and weight of the end cap are large, and the tie rod will stretch and become longer after being stressed, which will affect the effect. Only suitable for medium and low pressure hydraulic cylinders with a small length.


(5) Welding connection has high strength and simple manufacture, but it is easy to cause deformation of the cylinder during welding.