Patent ID: 7101307
Filing Date: 2006-09-05
Classification: B60K,F16H,Y10T

Abstract:
1. A method of varying a transmission ratio between a first motor and an output shaft using a second motor, comprising the steps of: providing a first motor, a second motor, an output shaft and a planetary gear set including a ring gear, a sun gear and a carrier which supports at least one planet gear; coupling the first motor, the second motor, and the output shaft each to one of the ring gear, sun gear and carrier; producing a rotary output at the output shaft, wherein the transmission ratio between the first motor and the output shaft is varied by varying the speed of the second motor, wherein the speed of the output shaft increases when the speed of the second motor increases and the speed of the first motor is held constant, the producing step being carried out by varying the rotating speed of the second motor so that the first motor operates at a speed within a desired performance range, the producing step being carried out with the desired performance range being a range of less than 1000 rpm for the first motor while the power output increases 50% of a peak power output.