Hydraulic cylinder is a kind of energy conversion hydraulic actuator which converts hydraulic energy into linear motion mechanical work. Before installation, the surface quality of the seal should be checked first, and the geometric dimension and accuracy of the seal should meet the standard requirements.
Installation method of hydraulic cylinder sealing ring:
Before installation, the surface quality of the seal should be checked first, without flash, burr, crack and trimming. The geometric dimension and accuracy of the seal should meet the requirements of the standard.
The combined sealing ring for hole is composed of O-ring and wear ring
The O-ring is easy to install because of its high elasticity; However, the elasticity of the wear ring is poor. If it is installed directly, the steps and grooves of the piston are easy to scratch the sealing surface, which affects the sealing effect. In order to ensure that the wear ring will not be damaged during installation, some installation measures should be taken. The wear ring is mainly made of filled polytetrafluoroethylene (PTFE) material, which has the characteristics of corrosion resistance and high coefficient of thermal expansion. Therefore, before installation, soak it in 100 ℃ oil for 20 minutes to make it soften gradually, and then install it into the groove of the piston with the tooling shown in Figure 2.
The tooling is composed of positioning sleeve and expanding sleeve. There is a 5O chamfer on the head of the positioning sleeve, which is used to guide the O-ring and wear ring into the groove of the piston end. The expansion sleeve is made of 65 Mn steel with good elasticity by heat treatment, and processed into a symmetrical 8-petal structure. It should be noted that when processing the small holes at the bottom of each flap, the graduation should be uniform, and when milling each flap, the saw should be aligned with the center of the small hole, so as to ensure that each flap of the sleeve can be expanded evenly. At the same time, all parts should be (smooth) chamfered to avoid damaging the sealing ring.
Each type of seal ring should have a set of corresponding tooling to ensure its assembly requirements. After installation, the seal ring shall not be wrinkled, twisted, scratched or reversed.
For the hydraulic cylinder, the threaded hole on the cylinder is usually processed after the welding process, so it is inevitable to produce burr at the junction of the outlet of the threaded hole and the inner wall of the cylinder. In order to remove the burr, the special tool must be designed and made to process it to achieve the purpose of smooth transition. Structure of special tool. When in use, insert the tool bar from the threaded hole, then install the tool head on the tool bar from the side, and rotate the tool bar to remove the burr and process a smooth and complete surface.
Another kind of seal is Y-ring made of polyurethane, which is widely used in hydraulic cylinder because of its high hardness, high elasticity, oil resistance, wear resistance and low temperature resistance. The inner and outer lips of the utility model can be made into unequal height shapes according to the shaft or the hole, so as to play the role of sealing and self-protection. Unequal high lip Y-ring, its short lip contact with the sealing surface, small sliding friction resistance, good wear resistance, long service life; There is a large amount of pre compression between the long lip and the non relative moving surface, so it is not easy to move when working.
Due to the high hardness and large amount of pre compression of polyurethane Y-ring, the seal ring is often broken, rolled and undercut during installation and replacement, which can not achieve the proper sealing effect or even fail. During assembly, we used a screwdriver to press the sealing lip inward along the cylinder bore; Or the outer lip of the sealing ring is tightly tied with a thin iron wire to make its outer diameter smaller than the inner diameter of the cylinder, and then the sealing ring is sent into the cylinder, and then the thin iron wire is drawn out. But these two methods are easy to scratch the seal ring, leading to seal failure and increasing maintenance time. In view of this situation, we use 0.lmm thick cold-rolled steel strip or copper sheet to cut it into a rectangle, the length of which is equal to the circumference of the outer diameter of the Y-ring, and then use it to wrap the sealing ring tightly, and then send it into the hydraulic cylinder bit by bit, and then pull it out after the outer lip is all in the cylinder, so the installation effect is better.
Contact: David Song
Add: Room 603,Xinsheng building 2#, Xinluo Road, Gaoxin district, Jinan, Shandong province, China