Oil Seal Check Before Installation, Clean And Intact
Oil seal (English name: oil seal) is used to seal the oil (oil is the most common lubrication medium transmission system) mechanical components, it will need to lubricate the parts and components of the transmission parts, and will not let the oil leakage The Sealing from the oil seal, features, structure type, working conditions and sealing mechanism can be divided into various forms and different names, but the habit of the general rotation of the shaft lip seal called oil seal.
The representative form of the oil seal is the TC oil seal, which is a rubber completely covered with a tight spring spring lip seal, the oil seal is generally referred to as the TC skeleton oil seal.
Oil commonly used materials are: nitrile rubber, fluorine rubber, silicone rubber, acrylic rubber, polyurethane, polytetrafluoroethylene and so on. When selecting the oil seal material, the compatibility of the material with respect to the working medium, the adaptability to the working temperature range, and the ability of the lip to rotate at high speed with respect to the rotary axis must be taken into account. General oil seal work when the lip temperature is higher than the working medium temperature 20 ~ 50 ℃, in the choice of oil seal material should be noted. The working range of the oil seal is related to the material used for the oil seal, for example, NBR is -40 to 120 ° C and the fluoro rubber (FPM) is -25 to 300 ° C.
The use of oil seal is quite extensive, with the engine as an example, some of the oil seal.
Hydraulic pump oil seal; oil seal; oil pump oil seal; camshaft oil seal; before and after the transmission seal; shift lever oil seal; before and after the transfer device seal; after the bridge half Shaft oil seal; differential (front) after the angle of the oil seal; wheel oil seal; direction of the oil seal; direction booster oil seal.
In short, all the operation of the body tank with liquid lubricants and connected with the external parts of the need for oil seal. Some are rubber, some are metal, mostly steel rubber, such as crankshaft oil seal, gearbox before and after the oil seal, left and right axle oil seal, the main reducer before the oil seal, air compressor crankshaft oil seal and other oil seal installation
1, the surface roughness of the shaft according to GB1801 with the oil seal in contact with the shaft surface, should be used grinding to surface roughness Ra0.2 ~ 0.63um, Rmax = 0.8 ~ 2.5um.
2, the shaft diameter tolerance according to GB1801 shall not exceed h11.
3, chamfer width according to GB13871-92 requirements.
4, the surface hardness: the material of the shaft with carbon steel and alloy steel is appropriate, the recommended hardness of HRC45 or more, when the media is dirty from the outside of contaminated impurities or shaft linear speed ≥ 12m / s, the shaft surface hardness Should be HRC50 ~ 60, quenching depth should be ≥ 0.3mm.
5, shaft chamfer 30 degrees (maximum), chamfer should not have burrs, sharp corners, and spiral processing traces, chamfer surface roughness Ra ≦ 3.2um, heat treatment of carbonation must be polished to clear.
(1) the surface roughness of the shaft is too high, oil seal easy to wear and leakage of oil.
(2) chamfer at the burr, sharp corners and spiral processing traces easy to scratch the oil seal lip seal caused by the initial seal failure.
(3) to avoid or reduce the shaft damage, trachoma, eccentricity and radial runout and other defects.
1, the surface of the surface roughness according to GB1301 provisions: outsourcing of plastic Ra3.2 ~ 6.3um, exposed skeleton Ra0.8 ~ 3.2um.
2, aperture tolerance according to GB1801 shall not exceed H8
3, chamfer length by GB13871-92, seat hole chamfer minimum 15 degrees, the maximum 25 degrees, chamfer surface roughness requirements and the same diameter.
Aperture chamfer angle greater than 45 degrees or no chamfering, easy to cause the oil seal caused by bite or scratches caused by oil seal diameter and assembly tilt and oil seal skeleton deformation, easy to oil seal machine early oil or oil leakage.
Check the oil seal before installation, if the oil seal clean and intact, and then pressed into the oil seal, one-way return line of the oil seal must be installed on the oil seal on the direction of the arrow and the axis of rotation in the same direction, do not install anti.
Protection of the main lip seal requirements
1, oil seal with a spline, keyway or hole of the shaft should be used when the warhead protection tooling.
2, warhead tooling surface roughness Ra max no more than 3.2um, not allowed to touch the burr and so on.
3, the outer diameter of the oil seal, the main lip assembly must be coated with a layer of lubricant.
4, oil seal assembly should be used in uniform speed and pressure to prevent the spring off.