The planetary gear train has been used as a core element for most of automatic transmissions (AT) due to its unique advantages: such as high power density, lower noise level, lower support bearing cost, and easier for mass production, compare to lay shaft or other types. In particularly, when multiple-pinion (MP) arrangement is used to accommodate flexible packaging design specifications. However, the planetary gear train does inherit a critical limit that is the lack of flexibility on gear ratio selection, because it needs to comply with certain constraints on tooth combination to meet gear train installation for assembly, load sharing for durability and phasing arrangement for noise concerns.
To fully take the MP advantages for AT transmission applications, while increase the gear ratio selection was the primary motivation that prompted us to seek for some potential solutions on the MP arrangement. This report will provide the method for the proposed approach, and also reveal some of the associated assessment results.
