Understanding of oil seals!
What is an oil seal?
An oil seal is a sealing element used to seal the rotating shaft in mechanical equipment, and the cavity is basically stationary (see the figure below), so the oil seal is also called a rotating shaft lip seal.
The friction part of the machine has oil entering when the machine is running. In order to prevent the oil from leaking from the gap of the machine, an oil seal is used. In addition to oil, it is also necessary to prevent the leakage of water and chemical liquids and the invasion of dust and sand from the outside. At this time, an oil seal is also used.
The sealing state of the oil seal is that the outer edge of the oil seal and the cavity are statically sealed, and at the same time, the outer edge of the oil seal is reliably positioned between the cavities. The second is the sealing state between the oil seal lip and the shaft. When the shaft rotates, it is a dynamic seal, and when the shaft is stationary, it is a static seal. The combined effect of various influencing factors and their interaction have a great impact on the sealing performance and service life of the oil seal.
Main uses of oil seals
Seals for engine crankshafts and camshafts
Seals for transmission systems (such as gearboxes, hubs, axles, differentials) of cars, motorcycles and commercial vehicles
Seals for transmission systems of agricultural machinery and engineering machinery such as forklifts and excavators
Seals for industrial gearboxes
Seals for hydraulic components (pumps, motors)
Seals for daily-use washing machines
Widely used in mechanical engineering and equipment processing industries
Main features of oil seals
The outer surface of the oil seal is cylindrical to ensure the static sealing of the cavity - the outer edge of the rubber with a metal skeleton inside; the outer edge of the exposed metal skeleton is mostly polished and plated with anti-corrosion coating.
The spring-loaded sealing lip ensures the sealing reliability of the dynamic and static sealing of the shaft. As a result of long-term development and research, the sealing lip structure of the oil seal has been improved to excellent performance, thereby improving the sealing reliability in a wider load range.
Adding dustproof lips, or multiple dustproof lips in special circumstances, can prevent external pollutants and dust from invading.
Rotary oil seals
Generally speaking, oil seals are skeleton oil seals, which are commonly used in rotating shafts of automobiles and motorcycles, that is, rotating shaft lip seals. The skeleton oil seals and Y-type dustproof rings produced by our factory are widely used in various rotating shafts. They are good rotating shaft lip seals with high quality and low price. Welcome to contact us.
Design requirements for rotating shafts
The surface hardness of rotating shafts is generally 30~40HRC. When installing the oil seal, in order to obtain the appropriate initial radial force, the interference requirement of the lip on the rotating shaft should be ensured, and the values are shown in the table:
The interference between the oil seal lip and the shaft
The maximum eccentricity of the oil seal during use should be strictly controlled to ensure the sealing effect. The eccentricity is shown in the table:
Notes on replacing oil seal and installation
Replacing oil seals:
1. When disassembling the installation part of the oil seal, be sure to replace it with a new one.
2. When removing the oil seal, please do not damage the inner surface of the cavity hole.
3. When replacing with a new oil seal, leave a gap of about 2mm in the cavity hole. When the lip end of the new oil seal contacts the shaft, the contact part of the old oil seal is removed.
How to install the oil seal:
1. First, apply a thin layer of lubricating oil or mineral oil on the surface and chamfer of the shaft. When inserting the shaft into the oil seal or while inserting it, prevent the lip part from rising.
2. Please carefully insert the shaft into the oil seal, keeping the center of the oil seal concentric with the center of the shaft.
3. When installing the shaft into a heavy cavity or inserting a long shaft into a cavity assembled on the machine when installing the oil seal, force is applied to a part of the lip and the end of the lip is damaged. Therefore, please assemble the shaft and the cavity before assembling the oil seal. When the oil seal cannot be installed later, please consider setting up a guide device for the cavity and the shaft.