In recent years, Automatic Transmission (AT) has become more and more multi-stage in order to reduce the fuel consumption of cars.Due to changes in the AT multistage design, the needle roller and cage assemblies of planetary gears need to accommodate high speeds.In addition, multiple ATs lead to an increase in the number of components, requiring smaller and lighter needle roller and cage components to reduce weight.

This causes the needle roller and cage assembly to be subjected to high loads to produce the same level of torque as a conventional AT.Moreover, in order to reduce the rotating resistance of the various components in the AT to save energy, the viscosity of the oil in the AT tends to decrease, and the operating conditions of the needle roller and cage components become more and more demanding.

In order to cope with harsh working conditions, the newly developed products adopt "carburized steel welded cage" and "new crown roller with high bearing capacity".

The cages are made of carburized steel with higher strength than the traditional low carbon steel, which improves the fatigue strength and the high speed rotation performance by about 10% compared with the traditional products.

For rollers, the crown of the circular arc is further optimized to stabilize the motion of rollers during rotation.Compared to traditional products, the newly developed product is able to reduce noise levels by about 8% and meet quieter EV requirements.The optimized crown shape can also suppress increased contact and edge stresses and even tilt, improving the loss of bearing life due to surface damage under harsh lubrication conditions.