NSK says it has developed the world's smallest roller thrust needle bearing for planetary gear mechanisms for use in automobile multistage automatic transmissions (AT).
Washers (slide bearings) are used in planetary gear mechanisms for step AT but their friction loss reduction has become an issue.
To solve this, NSK notes it has developed the world's smallest roller at a diameter of Φ1 mm x length 1.8 mm, making it possible to replace the washers with thrust needle bearings. This solution significantly reduces friction loss.
NSK is targeting JPY1.8bn in global annual sales in 2020, enhancing the efficiency of step AT's and increasing automobile fuel efficiency.
The number of planetary mechanism increases along with the multistage design of step AT. Therefore the number of washers (slide bearings), which comprise the planetary mechanism, increase. This results in the generation of friction loss, which then becomes an issue.
NSK developed a thrust needle bearing that is the same size as the washer (slide bearing), and it can thereby replace it.
This product reduces friction loss and improves durability in high-speed revolution environments.