A constant power, double-cage version of a constant power-continuously variable transmission CP-CVT. is analysed. Constant power is obtained by automatically adjusting the transmission ratio in accordance with the resisting torque. In order to asses the limits of the power and torque achievable by the device, tests were carried out to measure the traction coefficient for a special traction fluid. If was found that the traction coefficient has a linear variation with sliding-rolling ratio, up to values of 0.06-0.08, depending on temperature, and maximum values ranging between geometri0.08 and 0.1. This allowed a value of 0.05 for the traction coefficient to be chosen for the design calculations of the device. The transmission ratio and the torque depend on the dimensions of the elements of the variator and the type of the force which loads the contacts between the active elements. The combination of transmission ratio and torque give the constant power characteristics of the device. It was found that the lowest variation of the output power is obtained for a certain range of values of the geometrical parameters of the device. The parameters that were optimised are the contact angles between the intermediary spheres and the input and output conical discs, beta and gamma respectively and the radii of the spheres. The optimisation was made for elastic force acting on the toroidal disc. The diameter of the intermediary spheres influences the transmission ratio and the torque and determines to a large extent the transmitted power and the overall dimension of the CP-CVT. Obviously, any value of this diameter can be chosen according to the requirements of the transmission but this has to accommodate a minimal variation of output power with reasonable high torque transmitted.
Double-cage constant power continuously variable transmission (CP-CVT)
Gleichmäßig variables Getriebe mit konstanter Kraft und doppeltem Käfig (CP-CVT)
2006
8 Seiten, 9 Bilder, 22 Quellen
Aufsatz (Konferenz)
Englisch
Double continuously variable transmission steering mechanism
Europäisches Patentamt | 2015
|Constant Power Continuously Variable Transmission (CP-CVT): Operating Principle and Analysis
Online Contents | 2005
|