Study on high speed traction drive CVT for aircraft power generation (Analysis of ratio-changing response)

The traction drive - integrated drive generator (T-IDG®) has been developed since 1999 to replace current hydrostatic transmission drive generators. The T-IDG® consists of a generator and a half-toroidal traction-drive continuously variable transmission (CVT), which maintains a constant output speed of 24,000 rpm. In terms of coping with recent trends of high-power electric drive aircraft (MEA) and the need for weight reduction, a high-speed traction-drive CVT is advantageous over current hydro-static drive transmissions. To control a speed ratio of the high-speed CVT accurately, it is essential to know the speed-changing response. In conventional study, the speed-changing response is approximately proportional to a rotational speed; however, in the high speed CVT, a minute deformation during the speed change affects its response. This paper describes the analysis and a developed theory of the speed-changing response of a toroidal CVT, with showing test results which verify the response of the high speed CVT, whose input speed is 20,000 rpm at maximum with a peripheral speed of traction contact of 70 m/s.