The Role Of The Oil Seal:
The role of the skeleton oil seal is generally to isolate the parts that need to be lubricated in the transmission parts from the output parts, so as not to allow the lubricating oil to permeate. It is usually used for rotating shafts and is a rotating shaft lip seal. And there is a member of the skeleton oil seal, which is more reliable and durable than the general skeleton oil seal, that is, the reciprocating skeleton oil seal.
Structural features of reciprocating skeleton oil seal:
(1) Compared with the general type, the reciprocating skeleton oil seal has the characteristics of complex shape and high accuracy of external dimensions. Composed of 3 parts, including metal frame, spring ring (including main spring and auxiliary spring) and rubber body, the sealing lip is divided into main lip, secondary lip, dust lip and air sealing lip according to the different sealing parts. Among them, the main lip is the most important sealing part, which plays the most important role in preventing leakage.
(2) In the reciprocating skeleton oil seal, the main function of the metal skeleton is to increase the rigidity of the reciprocating skeleton oil seal, prevent plastic deformation, and facilitate installation. The main function of the spring ring is to provide appropriate radial holding force to the piston rod. After the lip wears out, it can automatically compensate to improve the sealing performance, but only the main spring function is considered in the article.
Working principle of reciprocating skeleton oil seal:
(1) The reciprocating skeleton oil seal is a sealing component that prevents the reciprocating shaft or piston from leaking. Its sealing principle is that the sealing lip is in direct contact with the shaft. On the one hand, an interference fit generates contact pressure, and on the other hand, an oil film is formed between the lubricating oil side and the air side to prevent leakage.
(2) Relying on the special pressure layout of the lip to produce a pumping effect during work. By making the oil film thickness of the inner stroke greater than the thickness of the outer stroke, and relying on the flow difference between the inner and outer strokes, the leaked lubricating oil is pumped back to the sealed cavity to achieve sealing.