Installation of sealing ring of the hottest hydrau

Installation of hydraulic cylinder seal ring

before installation, the surface quality of the seal should be checked first, and there should be no flash, burr, crack and trimming. For defects such as pores and looseness, the geometric size and accuracy of the seal should meet the standard requirements

the combined seal ring for hole is composed of O-ring and wear ring, and the brand popularity is further expanded (see Figure 1). Due to the large elasticity of the O-ring, it is easy to install; The elasticity of the wear ring is poor. If it is installed directly, the steps and grooves of the piston are easy to scratch its sealing surface, affecting the sealing effect. In order to ensure that the wear ring will not be damaged during installation, certain installation measures should be taken. The wear ring is mainly made of filled polytetrafluoroethylene (PTFE) material, which has corrosion resistance and large thermal expansion coefficient. Therefore, before installation, soak it in 100 ℃ oil for 20min to gradually soften it, and then install it into the groove of the piston with the tooling shown in Figure 2

the tooling shown in Figure 2 is composed of positioning sleeve and expansion sleeve. There are 5 chamfers on the head of the positioning sleeve, which are used to guide the O-ring and wear ring into the groove at the end of the piston. The expansion sleeve is made of 65 Mn steel with good elasticity after heat treatment and processed into a uniform and symmetrical 8-lobe structure. It should be noted that when machining the small holes at the bottom of each valve, the graduation should be uniform. When milling each valve, the saw mouth should be aligned with the center of the small hole. The more important aspect is to record each fresh face of this group to ensure that each valve of the expansion sleeve can expand evenly. At the same time, all parts should be chamfered (smooth) to avoid damaging the sealing ring

each specification of sealing ring should have a set of corresponding tooling to ensure its assembly requirements. After installation, the sealing ring shall not be wrinkled, twisted, scratched or installed reversely

Figure 3 shows the hydraulic cylinder barrel. The threaded holes on the cylinder barrel are often processed after the welding process, so it is inevitable to produce burrs at the junction of the threaded hole outlet and the inner wall of the cylinder barrel. In order to remove burrs, special tools must be designed and made to process them, so as to achieve the purpose of smooth transition. The structure of the special tool is shown in Figure 4. When in use, first insert the cutter bar from the threaded hole, and then install the cutter head on the cutter bar from the side. The original coal production capacity of Jixi is 31 million tons. The rotating cutter bar can remove the burrs and process a smooth and complete surface

another kind of seal is the Y-shaped seal ring made of polyurethane, which is widely used in hydraulic cylinders because of its high hardness, high elasticity, oil resistance, wear resistance and low temperature resistance. Its inner and outer lips can be made into unequal height shapes according to the shaft or hole, so as to play the role of sealing and self-protection. Unequal height lip Y-ring, its short lip is in contact with the sealing surface, with small sliding friction resistance, good wear resistance and long service life; The long lip and the non relative moving surface have a large pre compression shrinkage, which is not easy to move when working

due to the high hardness and large pre compression shrinkage of the Y-ring made of polyurethane, the sealing ring is often crushed, rolled over, undercut and other damage phenomena during installation and replacement, so it cannot achieve the due sealing effect, or even fail. During assembly, we used a screwdriver to press the sealing lip inward along the cylinder diameter; Or bind the outer lip of the sealing ring tightly with fine wire to make its outer diameter less than the inner diameter of the cylinder, then send the sealing ring into the cylinder, and then pull out the fine wire. However, these two installation methods are easy to scratch the seal ring, resulting in seal failure and increasing maintenance time. In view of this situation, we use 0.1mm thick cold-rolled steel strip or copper sheet to cut it into a rectangle. The length of German reprap is equal to the perimeter of the outer diameter of the Y-shaped ring, and then use it to wrap the sealing ring tightly, and then send it into the hydraulic cylinder barrel bit by bit. After the outer lip is all entered into the cylinder barrel, we can extract it. The installation effect is good. (end)