How to choose a shaft seal

Thread Content

In the operation process of modern mechanical equipment, preventing lubricating oil leakage and external impurity intrusion is a key link to ensure the normal operation of the equipment. Among them, magnetic oil seals, bearing isolators, skeleton oil seals, etc. are basic and important sealing components. With their advantages of compact structure, easy installation, reliable sealing, and moderate cost, they are widely used in sealing scenarios of various rotating shafts. How to choose the right seal for rotating shaft equipment is particularly important. This article will outline the sealing advantages and disadvantages of magnetic oil seals and skeleton oil seals. The working principle and structure of the skeleton oil seal. The skeleton oil seal is mainly composed of three parts.: Metal skeleton, rubber sealing lip, spring, the principle is that the sealing lip and dust-proof lip are close to the rotating shaft, and the built-in spring ensures that the oil seal and the shaft are in tight interference contact. The skeleton oil seal seals through the friction between the lip and the shaft, and prevents external contamination from invading the bearing box. 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 ； Causes oil seal and shaft wear ； No oil film will also cause heating, lip wear and cracks, spring falling off or failure, oil seal deformation and flipping or twisted outer ring leakage, etc. The working principle and structure of the magnetic oil seal. The magnetic oil seal is mainly composed of two parts and multiple parts.: Moving rings, static rings, permanent magnets, composite materials, sealing rings, static ring seats, etc., through the integrated design of "magnetic force compensation + sealing surface friction technology", the sealing of rotating shaft equipment can achieve zero leakage, no shaft grinding, long life, low power consumption, ensure smooth operation, prevent the loss of lubricating oil, resist high temperatures, and prevent external pollution from invading the bearing box, and meet the 6S on-site management requirements necessary for modern enterprises. moving ring: It is installed on the shaft and rotates with the shaft through O-ring interference. It has built-in high-performance permanent magnets (such as neodymium iron boron or samarium cobalt). The sealing end face is made of composite materials, which has high wear resistance and thermal conductivity. static ring: It is installed on the gland or cavity and remains static. It is usually equipped with special stainless steel or various alloys and other materials to provide smooth, wear-resistant and heat-resistant sealing effect. sealing ring: Fluorine rubber (FKM) -40℃ ~ +200℃ or perfluoroether rubber (FFKM) -40℃ ~ +300℃, resistant to high temperature, oil, chemical corrosion, aging, solvent and other magnetic compensation systems: The axial magnetic attraction generated by the permanent magnet directly acts on the dynamic and static rings of the product and they are always stuck together. The magnetic force does not decay over time, achieving macroscopic zero leakage. The magnetic oil seal does not rub against the shaft during operation, which increases the service life of the equipment. Magnetic force compensation ensures uniform stress on the end faces of the dynamic and static rings, close fit, and no fatigue work. The friction coefficient of the friction surface is 0.02, which generates low heat and does not require an auxiliary cooling system. It prevents oil leakage and the intrusion of external impurities (water, gas, dust), does not wear the shaft, has low power consumption, long life, high temperature resistance, corrosion resistance, etc., and reaches the IP68 sealing level. Based on the above characteristics, the applicable equipment range of magnetic oil seals has been widely used in reducers, gearboxes, fans, pump equipment, new energy vehicle motors, etc., replacing traditional oil seals to solve the problem of oil leakage in high-speed shafts. Magnetic oil seals play an indispensable role in the safe and reliable operation of mechanical equipment. Correctly understanding its working principle, rationally selecting materials, and standardizing installation operations can extend the service life of the oil seal and the entire machine. Today, as industrial manufacturing continues to pursue efficiency, greenness, and intelligence, technology is also constantly advancing, providing a solid guarantee for the reliable operation of modern equipment.