What are the basic structures of a hydraulic cylinder?
1 Answers
The main components of a hydraulic cylinder include the cylinder head, cylinder cap, cylinder barrel, piston, piston rod, guide sleeve, sealing elements, and tie rods. The specific details are as follows: 1. Cylinder head and cylinder cap: Typically made of rolled steel or cast iron. 2. Cylinder barrel: Usually constructed from seamless steel tubing, with the inner bore machined to a high surface finish to reduce friction and extend the lifespan of the sealing elements. The piston is mostly made of cast iron or steel and is secured to the piston rod using various methods. Exhaust and cushioning are valuable options on most cylinders and can often be added without altering the overall dimensions. 3. Piston rod: Generally made of high-strength steel, the piston rod undergoes surface carburizing, quenching, grinding, polishing, and hard chrome plating to enhance wear and corrosion resistance. Corrosive environments typically require stainless steel rods, which can be chrome-plated for wear resistance or first nickel-plated followed by hard chrome plating to meet corrosion resistance requirements. 4. Guide sleeve: Supports the piston rod during its back-and-forth movement. Most are made of nodular cast iron and can usually be removed without disassembling the entire cylinder. The rod sealing assembly typically includes an external wiper seal to remove dust and contaminants from the rod and prevent their ingress. A primary seal is used to contain the hydraulic pressure inside the cylinder. High-pressure cylinders also incorporate a pressure buffer ring before the primary seal to reduce the pressure on the main seal, thereby improving its sealing effectiveness and lifespan. 5. Sealing elements: Generally made of nitrile rubber, polyurethane, fluororubber, or filled PTFE. Typically, O-rings are used for static sealing applications such as between the cylinder barrel and guide sleeve or piston and rod, while Y-type seals, V-type seals, or composite seals are employed for sealing the piston and piston rod. The piston support ring is made from a special high-performance polymer material produced by Parker. In harsh operating conditions and high-dust environments, measures are taken to prevent contaminants and dust from settling on the piston rod. 6. Tie rods: Usually made of high-strength steel with cut or rolled threads. They are pre-tensioned with appropriate torque to prevent component separation under pressure and eliminate the need for locknuts, although locknuts are sometimes used.
