NSK Ltd. (NSK; Headquarters: Tokyo, Japan; President and CEO: Toshihiro Uchiyama) announced that it has developed a new bearing with high-speed capability and excellent sealing performance for use in automotive belt idlers and tensioner pulleys.
By improving the traditional seal, the new product delivers both durability at high speeds and excellent sealing performance. This product contributes to greater automobile reliability in markets with harsh driving environments. NSK is targeting 1 billion yen in global sales of this product in 2020.
Idler: This part enables universal adjustment for the wrap angle and layout of the front engine accessory drive (FEAD) belt.
Tensioner: This part keeps the constant tension in the FEAD belt.
In recent years across the globe, automotive engines have become more compact to increase fuel efficiency. To meet this trend, bearings for idlers and tensioners are required to support high-speed revolutions to work with smaller pulleys.
On the other hand, the demand for automobiles is increasing in developing markets. Often the conditions in these regions are severe for automobiles, where a great deal of water and dust can enter the engine compartment. The idler and tensioner pulleys are located in the front of the engine compartment. Because of this, bearings for idlers and tensioners must have excellent sealing performance.
Traditional high-speed seals were designed with a shape that reduced the effects of the centrifugal force. However, their highly rigid shape caused significant reaction force fluctuations, which could generate gaps in the seal lip.
By designing a flexible seal lip on the traditional high-performance seal, NSK enhanced follow-ability and improved seal performance. However, the high-speed revolutions caused significant reaction force fluctuations, raising concerns about seal lip damage.
NSK has now developed a new bearing with excellent sealing performance and high-speed capability for idler and tensioner applications by optimizing the shape of the seal lip.
High-speed capability: Delivering the same toughness at high speeds as traditional high-speed seals: The effects of increased centrifugal force on the seal lip at high-speed revolutions have been reduced by using an optimized center of gravity for the seal lip. This stabilizes seal lip movement for a high-speed resistant structure.
Excellent seal performance: Seal is more than twice as strong as the traditional design: A highly flexible shape in the seal lip reduces reaction force. This design enhances the contact condition of the seal lip and reduces ingress of contamination. The space between the seal and bearing part (inner ring) consists of a labyrinth design, preventing ingress of contamination from outside the bearing.
Product Benefits: This new seal improves idler and tensioner bearing reliability in markets with harsh driving environments.