Design skills of hydraulic seal ring

    Chamfer seal is a junction of seal, the O-ring will be fitted to a produced by chamfering groove and then squeeze through the shell to create a seal. The design of the main considerations of the product must be carried out a slight tension, the amount of compression is appropriate to reduce, the filling rate is appropriate to increase. The chamfer is generally 15 degrees ~30, based on the working pressure of selection pressure, angle to converge to the small value. On the contrary, it takes a large value.

Joint hydraulic sealing ring is static seal, without considering the hydraulic sealing ring is arranged to O type hoop groove deformation and other assembly effect, a simple calculation joint diameter (d ") unilateral amount of interference for 10 to 20 wire can be that 0.1 ~ 0.2mm.

Of course considering the parts dimension tolerance (O-ring section diameter, diameter O-ring sealing surface diameter size, type O hoop groove size and groove sides size), the eccentricity of the coaxial degree and location of equipment can further calculate the assembly of unilateral move closer to the limit of time, ensure the loose side interference is not negative. In order to further determine the sealing surface and the O type ring slot, bank size and tolerance. Then calculate d 'values (O type sealing ring groove diameter) d' d2=d1/1.03-1.07D1--O 2H =d2 sealing ring diameter according to the sealing gap and pressure to select the appropriate hydraulic sealing ring hardness, hardness rubber should be with pressure level and gap size changes high pressure, large gap hardness should be slightly larger, on the other hand is slightly small.

Hydraulic seal ring damage is one of the important reasons is under the working pressure is squeezed into the gap in C, the gap of allowed values and work pressure, the hydraulic sealing is related to the hardness of the rubber ring and the cross section diameter d0, see Table 4.

Hydraulic sealing ring compression amount can directly influence to the performance and the service life of the seal, the amount of compression is too small, the sealing effect is not well; too much compression, is disadvantageous to the o - ring assembly, increase resistance to the movement of the friction, service life will be shortened. Therefore, in the design process, to reasonably control the compression of the O type ring, the compression rate of 7%~30% is generally. The section diameter compression of the hydraulic seal ring is 5%~3.5%, which is used to obtain the partial large value for the fixed seal, which is used for the small value of the moving seal.

To ensure a reasonable sealing performance, dynamic seal and static seal must have the appropriate surface roughness. General static seal Ra6.3 m~Ra3.2 mu m, dynamic seal Ra3.2 m~Ra1.6 mu m. But not the roughness is good, if the installation surface roughness is too high, poor flatness, there will be some ribs. On the one hand, the hydraulic seal ring O ring is compressed, and some face due to the tight seal and oil spills. On the other hand, O ring in the groove will be along with the high pressure to the direction of the low pressure sliding, resulting in the hydraulic seal ring O ring damage, causing leakage.

Hydraulic sealing ring of the tensile rate is too large, it will cause stress relaxation, resulting in the diameter of the hydraulic sealing ring O. A contact gap is formed between the shaft surface and the shaft surface, and the installation process can cause the vibration to fall off. At the same time, the hydraulic sealing ring O ring due to the uneven extrusion force, the impact of the O type circle of life. The tensile rate formula is as follows: delta = (d '-d1' /d1X100%) d '- nozzle diameter;