Transmission having multiple ratio planetary gear unit in series with an auxiliary gear unit

摘要

A multiple ratio transmission having a planetary primary gear unit producing forward ratios and a reverse ratio, and a planetary auxiliary gear unit in series with the primary gear unit producing a direct drive ratio and either an underdrive ratio or an overdrive ratio. The transmission produces six or seven forward ratios and two reverse ratios by combining the ratios of the primary and auxiliary gear units. Five friction clutches and brakes plus one one-way clutch control operation of the primary unit, and operation of the auxiliary unit is controlled by a clutch and a brake plus one one-way clutch. The same six or seven ratios can be achieved with a total of seven friction clutches and brakes in the primary and auxiliary unit by deleting the one-way clutches.