Affect the sealing performance of the bearings. These physical properties including temperature, viscosity and surface hydrophilicity etc.. Temperature changes not only affect the sealing degree of relaxation and parts size change, also with the gas viscosity is closely related. Gas viscosity with temperature increasing or decreasing and increasing or decreasing. Therefore, in order to reduce the influence of temperature on the sealing performance of the bearings, we are sealing design, make the design into the elastic valve seat with thermal compensation SKF bearing. Viscosity and fluid penetration ability. When under the same conditions, higher viscosity, permeability of fluid is smaller. Hydrophilic surface refers to a film on metal surface, to get rid of this layer of film. Because of the thin layer of oil film, will destroy the hydrophilic surface, resulting in clogging fluid channel.
The sealing quality sealing quality mainly refers to material selection, matching, manufacturing accuracy control. For example, the valve flap and valve seat sealing surface is consistent, can improve sealing. Circumferential waviness many characteristics, the labyrinth seal performance is good.
Changes in temperature or sealing structure sealing force, sealing structure would be changed. But these changes will affect and change the seal force side each other, reduce performance so that the bearing seal. Therefore, in the selection of the seal, must choose the seal having elastic deformation. At the same time, also want to pay attention to the width of the sealing surface. The reason lies in the sealing contact surface cannot pair perfectly, when the width of the sealing surface increases, it is necessary to increase the force for sealing.
The service life of the sealing surface than the pressure sealing pressure than the size of the sealing performance of the bearings and SKF bearings. Therefore, a very important factors of sealing surface than the pressure is. In the same conditions, pressure too will cause bearing damage, but the pressure is too small will cause bearing leakage. Therefore, we need to give full consideration to the specific pressure to the appropriate degree at design time.
Improvement of sealing surface roughness can also affect the sealing pressure than the size. Only increase the pressure, to produce plastic deformation, in order to achieve the sealing effect. But to prevent leakage, only through the low method roughness to, I′m afraid not enough. Aiming at the influence factors bearing sealing performance, in addition to methods reduce the sealing surface roughness, we can make improvement measures as follows:
According to the principle of sealing liquid, in production, but also can reduce the diameter of the capillaries to achieve the sealing effect. Usually used to improve sealing planeness side to reduce surface roughness method or by increasing the sealing force, resulting in plastic deformation of the side surface sealing results, thereby preventing the medium through the.
According to the principle of sealing leakage channel, if the sealing surface is metal, when the salient points not smooth in the first surface appearance, only load with small can then the irregular convex points to produce plastic deformation. When the contact surface increases, the surface roughness will become plastic and elastic deformation. At this moment in the two concave roughness will exist. Applying a can make the underlying material loading severe plastic deformation, and the two surface contact closely, along the line and circumferential direction to make these remaining path.
The soft sealing elastic plastic materials, such as in the design of ball valve, butterfly valve, which can be designed ring elastic valve seat, in a stuffing box packing spring load compensation by plastic deformation to achieve sealing.
Combined with the foreign successful experience fitness and circumferential waviness, through fine car reached a certain degree of agreement and circumferential waviness, if you want to improve the sealing technology, technology will change the processing, so that the sealing surface roughness can reach 4～ Ra0 •Ra0 •8um, it can achieve the seal effect of.
In the sealed bearing grease, can be sealed in a sealing with grease, it can achieve the destruction of hydrophilic surface, thereby blocking the fluid channel.
In the range of materials within the permission, to increase the pressure, the sealing surface micro peak flat, resulting in plastic deformation, causing the liquid to pass through, to achieve the effect of sealing.