How to Install Hydraulic Cylinder Seals

Common hydraulic seals used in hydraulic cylinders include the following types: dust rings, piston rod seals, buffer seals, guide support rings, end cap seals, and piston seals.

A hydraulic cylinder is a hydraulic actuator that converts hydraulic energy into linear mechanical work. Before installation, the surface quality of the seals should be checked first. The geometric dimensions and precision of the seals must meet the standard requirements.

Installation method for hydraulic cylinder seals:

Before installation, the surface quality of the seals should be checked first. There should be no burrs, cracks, cut edges, porosity, or other defects. The geometric dimensions and precision of the seals must meet the standard requirements.

Combined seals for bores consist of an O-ring and a wear ring: Because O-rings have high elasticity, they are relatively easy to install; however, wear rings have poor elasticity. If installed directly, the steps and grooves of the piston can easily scratch the sealing surface, affecting the sealing effect. To ensure that the wear ring is not damaged during installation, certain installation measures should be taken. The wear ring is primarily made of polytetrafluoroethylene (PTFE), which is corrosion-resistant and has a high coefficient of thermal expansion. Therefore, before installation, it should be immersed in oil at 100℃ for 20 minutes to gradually soften it before being installed into the piston groove.

The tooling consists of a locating sleeve and an expansion sleeve. The locating sleeve has a 5° chamfer at the head to guide the O-ring and wear ring into the piston end groove. The expansion sleeve is made of high-elasticity 65Mn steel through heat treatment and machined into a uniformly symmetrical 8-lobed structure. It is important to note that when machining the small holes at the bottom of each lobe, the indexing should be uniform, and the saw cut should be aligned with the center of the small hole when milling each lobe to ensure that the expansion sleeve lobes expand evenly. Simultaneously, all parts should be chamfered (smoothly) to avoid damaging the sealing ring.

Each size of sealing ring should have a corresponding tooling to ensure its assembly requirements. After installation, the sealing ring must not have wrinkles, twists, scratches, or be installed backwards.

Threaded holes on cylinder barrels are often machined after the welding process, which inevitably results in burrs at the junction of the threaded hole outlet and the inner wall of the cylinder barrel. To remove these burrs, a special tool must be designed and manufactured to achieve a smooth transition. The structure of this special tool is as follows: In use, the tool holder is first inserted into the threaded hole, then the tool head is mounted on the tool holder from the side. Rotating the tool holder removes the burrs and produces a smooth, complete surface.