As the core transmission component of the transmission, the bearing directly affects its operating efficiency, bearing capacity and service life, and plays three key roles in the transmission:

Precise support and positioning The gear shaft system in the gearbox realizes radial and axial positioning through the deep groove ball bearing, cylindrical roller bearing, etc. to ensure the gear mesh clearance is stable. For example, angular contact ball bearing is often used for high-speed input shaft, which can bear radial force and unidirectional axial force at the same time, so as to avoid gear displacement or deflection during high-speed rotation and guarantee transmission accuracy.

The needle bearing reducing friction and energy consumption is widely used in the planetary gear mechanism due to its small volume and high bearing capacity. Its wire contact structure can bear large radial load in the limited space, and the rolling friction coefficient is only 1/5-10/10 of the sliding friction, which significantly reduces the energy loss in the power transmission process and boosts the transmission to improve the energy efficiency.

Suitable for complex working conditions Aiming at high temperature of transmission (oil temperature can reach above 120 ℃), impact load and lubricating oil environment, special materials and processes shall be adopted for the bearing: for example, carburized and quenched bearing steel shall improve the abrasion resistance, phenolic resin or copper alloy shall be selected for the retainer to enhance the heat resistance, and the sealing structure shall prevent the leakage of lubricating oil and the intrusion of impurities, so as to ensure the long-term reliable operation under the dynamic working condition of frequent gear shift.

In the transmission of new energy vehicles, the bearing needs to adapt to a higher rotating speed (the rotating speed of some motors exceeds 15000 r/min). By optimizing the raceway curvature and adopting ceramic rolling elements, the temperature rise and vibration noise are further reduced to meet the strict requirements of electrification on "high efficiency, mute and long life" of the transmission.