A Development of the Traction Roller System for a Gas Turbine Driven APU

A new type of speed reduction device has been developed to drive an auxiliary power unit by small gas turbine engine with the speed up to 86,000 rpm. The device adopts a traction drive system with planetary roller arrangement. In the traction drive system, power is transmitted by the tractive force generated between the rolling elements. The device has the potential to be superior in efficiency together with lower noise level over conventional gear system specially in high rotating speed range.

A loss estimation study indicated that the sliding friction loss of the supporting carrier is the dominant one in this system. Therefore, the better efficiency will be attainable by improving the carrier configuration. It is understood from the study that excess oil supply into the race ways causes considerable drop of torque capacity together with the increased churning loss in the traction system.