The paper examines the transmission in terms of the reliability,
economics, and safety of the commercial vehicle in order to
establish criteria for future models.
Distinction is made between reliability, which measures
probability of required repairs, and serviceability, which measures
probability of successful maintenance operations within specified
limits. Both characteristics relate to the cost-effectiveness of
the vehicle and both must be promoted during the development stage
of vehicle design. A check-list of developmental measures to assure
these characteristics is presented. Finally, experimental testing
for both of these characteristics is required.
Economical operation of transmissions rests on two bases: amount
of operational losses, and appropriate selection of transmission
ratios. The paper concentrates on ratio selection and suggests
design approaches.
The final topic is driving safety which is discussed in terms of
alleviating driver concern for gear-shifting, permitting greater
concentration on other controls.