An Accurate Analysis Method to Calculate Planetary Gear Set Load Sharing under Non-Torque Load
2022-01-0789
03/29/2022
- Event
- Content
- Given their high-power density, large range of speed change, and reputation of being quieter than counter-shaft gear sets, planetary gear sets (PGS) have advantages to be applied in electric vehicle (EV) applications. Typical rear wheel drive automatic transmissions have only PGS in gearbox, and power is transferred by torque. Most electric drive units (EDU) equipped PGS are like a simplified front wheel drive automatic transmission. PGS is coupled with counter-shaft gear sets normally at planet carrier which has two functions: original planet pinion carrying and additional transfer gear mounting. The latter brings in non-torque power in PGS through the carrier. This condition hasn’t obtained enough attention by automotive gear researchers regarding to PGS load sharing calculation. Excluding non-torque load here causes underestimating gear and bearing uneven loads in both magnitude and variation. In extreme conditions, undersized parts would miss demanding durability requirements. One good example is wind turbine gearbox. With standard calculation, bearing failure during twenty-year service isn’t uncommon. Therefore, the effect of non-torque load was noticed in PGS load sharing evaluation of wind turbine gearbox. In this study, a validated deformable FEA contact analysis tool is used to create a virtual design, development, and validation (VDDV) method to calculate PGS load sharing in EDU. The method extends previous analysis works by including non-torque load. The VDDV method is also compared with PGS load sharing testing methods, which helps hardware reduction in future EDU development. Then, one specific example is used to implement the method for accurate PGS load sharing estimation. The non-torque load effect is explored by variation studies, and the results provide a validation foundation for more efficient analytical methods.
- Citation
- Ma, Q., and Black, D., "An Accurate Analysis Method to Calculate Planetary Gear Set Load Sharing under Non-Torque Load ," SAE Technical Paper 2022-01-0789, 2022, .