Paper 14. Automatic Gearboxes (Hydrokinetic) for Trucks and Buses

Abstract

This paper shows that the hydrokinetic transmission is no newcomer to the field of trucks and buses and that in public service vehicles, in semi-automatic form, it is virtually standard equipment. Economic pressures, increasing traffic densities, etc., will lead to greater use of fully automatic transmissions in buses, and several notable fully automatic hydrokinetic public service vehicle transmissions are reviewed. In the trucking field, economic considerations are also creating a trend to larger and more powerful vehicles which will demand ease and certainty of control, and thus a place for fully automatic transmissions. An examination of the format of commercially successful fully automatic hydrokinetic truck and bus transmissions reveals that transmission designers have made extensive use of epicyclic gearing, and the paper includes an appreciation of the characteristics and advantages of this type of gearing.