Press Release Summary:
Hybrid bearings, including angular-contact ball bearings and cylindrical roller bearing, combine steel raceways with silicon-nitride balls. Dimensionally interchangeable with ISO dimensioned bearings, hybrid bearings provide resistance to wear. They can operate without oil, using process fluid as lubricant. Silicon nitride balls have 50% higher modulus of elasticity than steel, increasing bearing stiffness.
Original Press Release:
SKF(R) Hybrid Bearings Provide Substantial Benefits for Rotating Machinery
Kulpsville, PA - SKF(R) now offers a range of hybrid bearings, including angular contact ball bearings, and cylindrical roller bearings. These bearings combine steel raceways with silicon-nitride balls to provide longer service life, under extreme operating conditions, than conventional all-steel bearings. In addition, laboratory and field tests show that SKF hybrid bearings last significantly longer than all-steel bearings, while providing a number of other operational benefits.
SKF hybrid bearings are dimensionally interchangeable with other ISO dimensioned bearings.
Advantages of silicon nitride balls and rollers
Low density - Ceramic rolling elements are 40% lighter than similarly sized steel rolling elements. This significantly reduces centrifugal loads and makes the bearings capable of high speed operation.
Low thermal expansion - Because silicon nitride has a very low coefficient of expansion, ceramic rolling elements are less sensitive to temperature differences between the inner and outer rings, also important in high-speed applications where temperature gradients are a concern.
High modulus of elasticity - When compared to a steel ball, a silicon nitride ball has a 50% higher modulus of elasticity. This increases bearing stiffness and improves the dynamics of the rotor/bearing system.
Low friction - Silicon nitride rolling elements have a surface finish much better than rolling elements of steel. This gives silicon nitride a lower coefficient of friction; providing cooler operation and resistance to wear even under poor lubrication conditions.
Oil-free operation - Researchers have tested SKF hybrid bearings and have shown that in a refrigeration or air conditioning compressor, the refrigerant can be used to lubricate the bearings. This means that in certain applications, SKF hybrids can be used successfully using the "process fluid" as a lubricant.
SKF is the world's largest manufacturer of rolling bearings and accessories. SKF USA Inc. employs approximately 5,000 people in the U.S., has nine manufacturing locations, and close to 1,500 authorized distributor branch locations. Worldwide, SKF sells its product line in more than 130 nations.
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