NSK Develops a High-Speed Angular Contact Ball Bearing for Oil-free Dry Air Compressors

Development background

Oil-free dry air compressors are used in the compression process to achieve compression without the injection of oil. Since these compressors contain no oil in the discharged air, they are finding use in more and more applications in products and environments that need to avoid exposure to oil. However, due to the fact that this compressor structure doesn't use oil, it requires three to five times the speed of oil-flooded compressors to achieve the same level of efficiency, resulting on growing demand for decreased noise, vibration and energy consumption. In response to this demand, NSK has developed an angular contact bearing that uses NSK's original cage material, L-PPS resin,^*1 for lower torque and vibration.

• *1: Linear polyphenylene sulfide is a high-strength resin that has a high level of heat resistance.

Product features

(1) Up to 40% less vibration than the current product

Vibration that occurs in the cage during high-speed operation is the major cause of bearing vibration. Through the following modifications, this product reduces that cage vibration:

• Introduction of the L-PPS resin realizes significant amount of weight reduction compared to the current machined brass cage.
• Equivalent level of dimensional accuracy to the current machined brass cage.
• Improved lubrication with the outer ring cage guide surface and cage surface by use of a special groove on the cage outside surface.

(2) Up to 30% less friction loss (torque) in the bearing compared to the current product.

The major cause of friction loss in the bearing is guide surface sliding friction between the cage and outer ring.
The new bearing halved the cage guide surface and reduced the cage weight, which achieves a reduction of bearing friction loss (torque)

Product benefits

1. Lower vibration and noise during high speed operation.
2. Low energy consumption.