Development of a Pressure-Controlled Clamping System for Continuously Variable Belt and Chain Transmissions

摘要

The transmittable power of continuously variable belt- and chain transmissions has been increased steadily in recent years so they have the potential for use in tractors up to about 100 kW. In the current common designs, the hydraulic system, which is required for clamping and ratio control, exerts a strong influence on the total losses. In order to increase the overall efficiency of such a transmission, new, pressure-controlled clamping hydraulics with significant higher efficiencies were examined with the aid of computer simulation. Among an expensive but exact solution a simpler approach is introduced. These studies focused on the realization of highly dynamic clamping pressure supply in cases of sudden torque increase, which occur frequently in tractors.