Principle and analysis of lubricating oil channel layout in electric drive axle reducer

The input speed is defined as 3300r/min, the density of a certain type of gear oil is 0.849g/cm3, the dynamic viscosity is 0.0217Pa·s, the temperature is set to 80℃, and the amount of oil added to the liquid level is specified to be 4.2L. The initial state is shown in Figure 5.

Figure 5 Initial test status

The distribution of gear oil on the reducer housing and cover side during forward rotation is shown in Figure 6. It can be observed that both the input shaft bearing and the intermediate shaft bearing have a stable source of lubricating oil. The oil entering the intermediate shaft bearing can flow into the differential bearing on the housing side along the oil groove, and each bearing is fully lubricated.

Figure 6 Gear oil distribution of reducer during forward rotation

The gear oil distribution on the reducer housing and cover side during reverse rotation is shown in Figure 7. It can be observed that both the input shaft bearing and the intermediate shaft bearing have a stable source of lubricating oil and are fully lubricated.

A sample of an electric drive axle assembly produced using the above principle was first subjected to a static oil level test to confirm the appropriate refueling position and the maximum and minimum refueling amounts; then lubrication tests at various speeds were simulated under loading and climbing postures. The test showed that within the speed range of 3000 to 12000 r/min, stable oil flow could be observed at each bearing, and the temperature could be maintained below 70°C and kept constant for a long time; subsequently, several vehicles equipped with this product also successfully passed the endurance road test.

Figure 7 Gear oil distribution of reducer during reverse rotation

Conclusion

At present, the electric drive axle with two-stage reduction has become the mainstream in the market, with many advantages such as low cost, few parts, good processability and high versatility. The oil baffle and lubricating oil channel cleverly arranged on the reducer housing and cover can ensure that the gear oil splashed by the first-stage passive gear or the second-stage passive gear can be collected under any working condition (especially the low-speed forward and reverse working conditions), and guided to each bearing to form a stable and sufficient lubricating oil flow, which can fully ensure the reliability of the drive axle.