Principle and application of the framework oil seal

Skeleton oil seal is a typical representative of the oil seal, the general said, referring to the Seal is the skeleton oil seal. Oil seal role is generally to transmission parts that need lubrication of components isolated from the output components, and will not allow the lubricant leakage. Play an enhanced role on the skeleton as the reinforcement of concrete structures inside and oil seals to maintain the shape and tension.

The skeleton oil seal, widely used in aerospace, automotive, motorcycle, railway vehicles, ships, home appliances, construction machinery and other industries. Applicable to the sealing of rotary motion and reciprocating motion. Installed in the re-model engines, transmissions, axles, ships, cylinders and other parts. Mainly to prevent the sealing medium (gas and liquid) permeability and external foreign objects into the body.

Form of the structure can be divided into single-lip skeleton oil seal lips skeleton oil seal. Vice lips skeleton oil seal lip from the dust and to prevent outside dust and other impurities from entering the inside of the machine. Skeleton type can be divided within the package skeleton oil seal, exposed skeleton oil seal and assembly of oil seal. Working conditions can be divided into the rotation skeleton oil seal and reciprocating skeleton oil seal. For gasoline engine crankshaft, diesel engine crankshaft, gearbox, differentials, shock absorbers, engine, axles and other parts.

Skeleton oil seal structure has three parts: oil seal body, strengthening the skeleton and tight coil spring. The seal body is divided into the bottom, according to the different parts of the lumbar skeleton oil seal structural map department, cutting edge and the sealing lip. Typically, the skeleton oil seal in the free state, the diameter is smaller than the shaft diameter, that is, a certain amount of interference. Therefore, when the oil seals after loading the oil seal seat and the shaft oil seal edge of the pressure and force of contraction of the coil spring from the tight on the shaft a certain radial tightening force, the pressure decreases rapidly after a period of time to run and even disappear, and thus, together with the spring can always compensate for oil seal from the tightening force.

Sealing principle: oil seal edge to control the oil film between the oil seal and the shaft, this film has a fluid lubrication characteristics.

Skeleton oil seal role in the stiffness of the film happens to make the film in contact with air-side to form a crescent surface to prevent the leakage of working medium in order to achieve the rotation axis of the seal. Oil seal sealing ability, depending on the thickness of the sealing surface of the film thickness is too large, the oil seal leak; the thickness is too small, dry friction may occur, causing the oil seal and shaft wear; no oil film between the seal lip and the shaft, you could easily cause heat, wear and tear. Therefore, during installation, you must put some oil in the ring skeleton oil seal and the vertical axis line, if not vertical, oil seal lubricant seal lip will be drained from the shaft will cause the sealing lip excessive wear. In operation, the lubricant in the housing slightly oozing a little, in order to achieve the ideal state form a film at the sealing surface.

The role of the skeleton oil seal is generally required in the transmission parts lubricated components and output components of isolation, will not let the oil leak, usually for the rotation axis, a rotary shaft lip seal. Skeleton like inside reinforced concrete structures, play an enhanced role, and the oil seal to maintain the shape and tension. Skeleton type can be divided into within the framework oil seal, outer skeleton oil seal, inside and outside the gel skeleton oil seal. Skeleton oil seal is a high quality nitrile rubber and steel made, stable quality, long life. Widely used in automobile, motorcycle crankshaft, camshaft, differentials, shock absorbers, engine, axle, front and rear wheels and other parts.

1, to prevent sand, dust, water vapor intrusion from the outside bearings;

2, the limit bearing lubricant leakage. The requirements of the oil seal is the size (diameter, diameter and thickness) should be required; require appropriate flexibility, can axis properly stuck, play a role in sealing; heat resistance, wear resistance, strength, resistance to media (oil or water, etc.), long service life.

Rational use of oil seals, should note the following:

(1) shaft speed due to the design and structural reasons, the high number of revolutions of the shaft should use the high speed oil seal, the low speed shaft using a low speed oil seal can not be low-speed oil seal for high-speed shaft, and vice versa does not work.

(2) the general pressure of the oil seal to withstand the pressure difference, too much pressure when the oil seal will deform. Pressure supporting circle or to strengthen the pressure seals should be used in excessive pressure conditions of use.

(3) The ambient temperature in the case of using the high temperature should be used in the polypropylene ester or silicon, fluoride, fluorine rubber. And should seek to reduce the oil temperature in the tank. The use of low temperature should be used in cold rubber.

(4) install the eccentric oil seal and the shaft with the eccentric is too large, then the seal will deteriorate, in particular, is particularly serious in the shaft speed is high. If the eccentricity is too large, we can use the "W"-shaped cross-section of the seal.

(5) Note that there should be a certain amount of lubricating oil in the oil seal lip.

(6) to pay special attention to dust immersed in oil seal.

(7) axis surface finish, and a direct impact on the life of the oil seal, ie, shaft finish, the president of the oil seal service life.