Abstract
Usually the transmission efficiency of hypoid gear is much lower than helical gear because of its large mesh loss between tooth flanks of pinion and crown gears. Moreover, the friction loss is also remarkable for automotive application since the pinion gear is overhang-supported by preloaded bearings to receive big axial force. Therefore, the improvement of efficiency is an old subject and becomes more important for current fuel economy. This study directly measured the transmitting loss torques of each part of hypoid gear by using a gearbox test rig, and reconsidered the famous Coleman’s efficiency formula of hypoid gear. As a result, the limit of Coleman’s formula is clarified, and several attempts for design high efficiency hypoid gear are tried and practically applied to new developed CVT transmission.
