Development Completion of long-life Thrust Needle Roller Bearing
JTEKT Corporation (hereinafter JTEKT) has developed a “long-life thrust needle roller bearing”, which achieves 3.5 times or longer life compared with conventional products.
The thrust needle roller bearing contributes to the reduction of power loss and is commonly used for the automotive transmissions, air compressors, or such parts of automobiles since it is compact and can be used in environments which require relatively high load and high rotation speed.
We contribute to the further weight-saving of vehicles and improvement of fuel efficiency with our developed product, and also replace currently volume-produced products with longer life ones.
The geometry of a thrust needle roller bearing causes “differential slide” due to the difference between internal and external circumferential speeds on the roller raceway. Thus, an issue of this bearing is flaking easily generated from the race surface.
(1) We added the shot peening process (technology to strengthen metallic material by shot-peening with a vast number of particles) in order to harden the race surface and apply the residual compressive stress as a countermeasure against “flaking from the race surface”. As a result, the life until flaking was improved to be longer.
(2) We also strengthened the roller through the special heat treatment based on assumption that the “roller flaking” can be generated more easily than “race flaking” because the life until race flaking was improved through the race strengthening.
-> Achieved 3.5 times or greater durability against flaking compared with conventional products
(1) Contributes to weight saving and fuel efficiency improvement of vehicles
An extended bearing life achieves a further size-reduction while maintaining the conventional life level. This contributes to the weight-saving and fuel efficiency improvement of vehicles.
(2) Able to extend life of existing volume production products
Since the long-life processing can be added to the conventional process, it is possible to replace to long-life bearings without changing the size of existing volume production bearings.
Even when the input torque is increased, a long-life technology can improve performance of existing products. Since the flow of lubricant is not required to be changed, changing points for the application development can be reduced, which eventually reduce the customer’s risk.