Abstract
KEYWORDS:
CVT, continuously variable transmission, belt, dry running belt, transmission
ABSTRACT:
The need to further reduce the fuel consumption has determined the car manufacturers to develop new types of automotive transmissions. A predominant role in the new wave of transmissions is represented by the various types of CVTs. Important advantages such as improved performances and fuel consumption, passenger comfort and safety make the CVT a strong competitor on the future automotive transmissions market.
The belt type CVT was used for the first time in 1958 in a mass production car. After this, its applications were limited to low power vehicles like scooters, snowmobiles and ATVs. This was due to the inherent disadvantages of the belt CVT: low torque and reduced belt service life. The much improved performances of the newly developed belts have opened new possibilities for the belt CVT as automotive transmission. The above mentioned disadvantages are compensated by the low production costs and the relatively low required clamping force. Whereas in the push-belt and chain CVT the clamping force is produced by means of a hydraulic system, in the case of the belt CVT, an electromechanical system suffices. The latter has a much lower energy consumption and production costs.
The aim of the research team at Konstanz University of Applied Sciences was to design a belt CVT transmission, able to handle torques of up to 200 Nm and with an electromechanical adjusting mechanism. In order to demonstrate the functionality of such a concept, a fully functional test bench was designed and constructed. The paper presents the design solution for the belt type CVT, the construction of the test bench and conclusions drawn after the first test results.