In the bearing seal assembly quality problem reason and solution

Bearing seal ring is bearing the assembly structure of a part, is commonly used in the assembly of the sealing ring quality stand or fall will directly affect the bearing sealing performance, or use will affect the service life of bearing. Bearing when use a lot of damage will be bearing seal assembly is good or not, that, in our daily common bearing seal assembly quality problems have? The bearing network ( Hereinafter referred to as: bearing network) According to the understanding of the bearing assembly knowledge to share about the reason and solution. Normally, the reason of quality problem in the process of bearing seal assembly has the following kinds: (1) seal belt; (2) seals don't fit; (3) sealing ring is easy to fall off; (4) lead bearing outer ring crack is larger; (5) bearing inner ring stuck; 6 seal lip in bearing rotation and flip it, and so on. 1 round of bearing seal belt, bearing seal belt is: refers to the bearing inner and outer ring in the process of rotating seal ring are also relative motion in the radial direction, usually seal, seal ring groove can't rotate. Existence reason mainly is the small size bearing seal guard, seal lip and inner ring within the sphere of interference quantity is greater than the seal ring with outer ring seal groove guard steps of interference, namely sealing ring and the steps of friction is less than the friction force of seal ring with outer spherical, the solution is: increasing bearing seal guard size and increased under the premise of guarantee the quality of seal assembly seal lip in size. 2, bearing seal joint bearing seal joint is: refers to the sealing ring assembled in labial ministry not against outside spherical cock, is usually called a bell mouth. Sealing ring is not fit will make bearing sealing performance is reduced, thus affecting the quality of products. The reasons for this phenomenon are: (1) the sealing ring in labial ministry interference quantity is too small; (2) the seal lip is too thin in easy deformation; (3) sealing ring can't reset after loading. According to the causes of different processing respectively: (1) within the bearing seal lip bell mouth caused by interference quantity is too small, must increase the sealing ring in labial ministry interference, the unilateral interference quantity according to the following formula to calculate F ( See figure 1) ； F＝( D2-D1) / 2 + e type: D2 - Seal lip diameter size; D1 - Inner ring cross section diameter size; e- The seal lip under conventional unilateral interference. (2) within the bearing seal lip deformation caused by the bell mouth, mainly within the lip is too thin to seal in the discharge process of plastic injection caused seal lip deformation, therefore, this kind of circumstance must increase the seal lip thickness ( As shown in figure 2 the shaded part) ； (3) the bearing sealing ring are no longer A bell mouth, sealing ring, in the process of bearing swing its head A point card within the seal groove, not return to original state ( See figure 3) Must be reduced or decrease the size of seal head width sealing ring outside diameter size. 3, bearing sealing ring is easy to fall off bearing seal off is: refers to seal off out of the seal groove. Seal assembly after the drop test is adopted to verify the strong degree and the causes of sealing ring off is: seal ring with outer ring seal groove guard steps, small amount of interference seal head by the length of the straight segment small guard. Therefore by increasing sealing ring guard size and long seal head straight length a (close to guard See figure 4) The method to increase its strong degree of assembly, at the same time, the existing seal groove appropriate increase sealing ring inside limited space, rim width b, increase the contact area of sealing ring in the groove, the greater the contact area, the greater the friction force of seal ring and outer ring, bearing oscillation, sealing ring is not easy to loose, rotation, sealing ring strong degree. 4, lead bearing outer ring crack is larger with the need of assembly, bearing outer ring diameter, there is a axial gap seal after loading, due to interference of the outer ring with axial joints increases, when the outer ring axial gap increases to a certain degree, will cause the user bearing installation difficulties, so the size of the outer ring gap should be strictly controlled, usually take 0. It is advisable to about 5 mm. For bearing guard position, in does not affect the assembly quality under the premise of reduced range of the seal ring with outer ring seal groove guard steps, to reduce the gap of outer diameter. , the bearing inner ring card five die after loading seals, bearing inner ring can't turn flexibly and even turn to be not moved, the phenomenon known as the inner ring. Is mainly used to reduce seal lip and the inner ring of the spherical volume, which increase sealing ring diameter d ( See figure 5) Reduce the amount, make the seal lip contact with the sphere. E, the second is to reduce the sealing ring of the waist size to seal the lips more elastic, reduce the sealing ring and the inner ring of the spherical contact pressure. In the seal design, ctoa alpha shoulds not be too big, can be see from figure 5, ctoa increase gradually from alpha and beta, linear distance from point A to point B, line BC contact with inner ring area of S1 + S2 than the straight line AC contact with inner ring area of S1 for large contact area of S2. In labial ministry interference quantity under the same conditions, the inner ring of the spherical sealing ring contact area, the greater the bearing rotational resistance, the greater the more easily jammed. At the same time, also can cause seal lip serious wear and tear, can't normal use. Thus decrease the ctoa alpha, also can increase the flexibility of the bearing rotation. According to the practical application of validation, ctoa alpha general about 45 ° is advisable. 6, sealing lip in bearing rotation and flip it bearing in the process of turning over its swinging Angle, reset the seal lip into the outer ring in the sphere of the phenomenon, referred to as sealing ring back. For this kind of phenomenon, the main solution is to reduce the inner ring and the seal lip of the spherical; Followed by the appropriate increase the sealing ring in the lips of rigidity and flexibility, which increase the thickness of the lip part ( As shown in figure 6 shadows (S) And to decrease the size of ring waist e. Only the lip seals have enough rigidity and elasticity, when bearing swing it won't happen.