Press Release

Water-Resistant Grease Ensures Longer Service Life for Hub Unit Bearings

Improves Durability in Products Designed for Harsh Operating Environments

Tokyo, Japan, September 29, 2010 — NSK Ltd. (NSK; Headquarters: Tokyo, Japan; President and CEO: Norio Otsuka) announced today it has developed hub unit bearings*1 that employ a new type of grease which helps prevent any significant decline in the service life of the bearings, even when exposed to water. NSK aims to grow sales of the new hub unit bearings in emerging markets, and targets annual sales of 2 billion yen by 2014.

*1 A hub unit is a part that integrates the bearing with the hub on which automobile wheels are mounted. Needless to say, very high reliability is demanded of the hub units designed to hold up the body of the vehicle while ensuring smooth ride.

Internal Structure of Hub Unit Bearings

In the emerging markets of the world, which include the BRICs (Brazil, Russia, India and China) where demand has been rapidly growing in recent years, roadways are often in poor condition, with many still unpaved and subject to flooding during rainy seasons. Hub unit bearings are installed on the part of vehicle closest to the road surface and often operated under severe conditions created by mud and water.

While NSK has continued to improve the performance of its bearing seals, there are still cases where minute volumes of water penetrate the unit under these severe wet and muddy conditions.

NSK has succeeded in developing a water-resistant grease that helps prevent any significant decline in the current service life of bearings, even if they are penetrated by water. The new water-resistant grease ensures longer service life and higher reliability of hub unit bearings.

Product features

The new water-resistant grease protects the bearing raceways and rolling elements by neutralizing the effects of any water that finds its way in.

Keeping water away from the raceway surface
Any water that contacts the grease forms into a large bead and is enveloped in a way that prevents it from direct contact with the rolling elements or raceway surface.
Bearing raceway protected by a special film
The grease also contains an additive designed to form a protective film on metallic surfaces, which prevents water from making direct contact with the rolling elements or raceway surface.

Relationship Between Rolling Fatigue Life and Grease

Relationship Between Rolling Fatigue Life and Grease

Overview of Water-Resistant Grease

Overview of Water-Resistant Grease