What exactly is an oil seal?

The lip of the Oil Seal contacts the shaft of the motor, and under the operation of the motor shaft, a layer of oil film will be formed at the contact between the lip and the shaft. The Sealing ability of the oil Seal depends on the thickness of the oil film on the sealing surface. If the thickness is too large, the oil seal will leak; If the thickness is too small, dry friction may occur, causing wear between the oil seal and the shaft. If there is no oil film between the sealing lip and the shaft, it is easy to cause heating, wear, and other conditions.

Therefore, during installation, some oil will be applied to the sealing area of the oil seal. At the same time, during installation, it is necessary to ensure that the Skeleton Oil Seal is perpendicular to the shaft, so that it is ideal for operation. Overall, when applying oil seals, it is important to strictly follow their technical requirements and pay attention to the following points:

1) Oil seals have requirements for rotational speed. High speed motors should use high-speed oil seals, while low speed motors should use low-speed oil seals.
2) There should be no impurities at the lip where the oil seal comes into contact with the motor, otherwise the oil seal may easily fail.
3) The surface finish of the motor shaft directly affects the service life of the oil seal. If the shaft has a high finish, the service life of the oil seal will be longer.
4) During assembly, ensure good concentricity and verticality, especially in areas of high-speed operation, otherwise it may lead to leakage.
5) Oil seals also have pressure requirements, and when applied in high-pressure fields, pressure resistant oil seals with pressure resistant support rings are required. If a general oil seal is used in a high-pressure environment, the oil seal will deform when the pressure is too high, leading to leakage.
6) Considering the environmental temperature, when the temperature is high, polypropylene ester or silicone, fluorine, or silicone fluorine rubber should be selected. And efforts should be made to reduce the oil temperature in the fuel tank. When the temperature is too low, cold resistant rubber should be used.
Generally speaking, an oil seal is a skeleton oil seal, which acts as a reinforcing steel bar in concrete. And enable the oil seal to maintain its shape and tension.
In our daily pump products, we use a skeleton oil seal, which consists of three parts: the oil seal body, the skeleton, and the self tightening spiral spring. Generally, in a free state, the inner diameter of the skeleton oil seal is smaller than the shaft diameter, and there will be a certain amount of interference when assembled. At the same time, when the pump drives the fluid to do work, the pressure inside the pump and the contraction force of the self tightening spiral spring generate a certain radial pressure on the shaft, which can prevent fluid leakage. After a certain period of operation of the pump, the interference will decrease, and the self tightening coil spring can supplement the self tightening force of the oil seal at any time.