A toroidal continuously variable transmission (CVT) that uses a traction drive to transmit torque has a vastly larger torque capacity than conventional CVTs. The authors have researched and successfully developed a half-toroidal CVT that features reduced spinning loss in the torque transmission unit and higher efficiency. The traction drive of this CVT transmits torque by means of the shear resistance of the traction fluid film, by taking advantage of the property that the fluid solidifies under high contact pressure. In this study, the specific influence of the various factors that increase or decrease the loading force produced by the loading cam was analyzed both theoretically and experimentally. At first, the performance of a conventional loading cam with a cylindrical cam roller is described. The performance of the new loading cam with a conical roller is outlined: 1. Structure of tapered loading cam; 2. Calculation of loading force of tapered loading cam (frictional force at rolling surface, frictional force of side bearings); 3. Measurement of loading force of tapered loading. The factors producing the loading force hysteresis of the loading cam used as the mechanism for generating loading force in a toroidal CVT were shown to be the spinning loss at the rolling surface and the friction at the roller sides due to centrifugal force, and the degree of influence of each factor were formed. A tapeted loading cam that does not produce spinning loss at the rolling surface of the roller was shown to reduce the hysteresis of the loading force substantially compared with the previous cylindrical loading cam.
Improvement of loading cam performance in a toroidal CVT
Verbesserung des Lastverhaltens der Kurvenscheiben in einem Toroid-CVT
JSAE Review ; 23 , 4 ; 481-487
2002
7 Seiten, 16 Bilder, 2 Tabellen, 5 Quellen
Aufsatz (Zeitschrift)
Englisch
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