Study of Effect of CVT Pulleys on Strength and Transmission Efficiency of Metal Pushing V-belts 2011-01-1426
In designing CVT pulleys, the effect of the fit clearance of the movable pulleys and their stiffness on the transmission efficiency and strength of the metal pushing V-belt is not necessarily clear. The research discussed in this paper introduced a pulley model that defined the pulleys as elastic bodies to a previously developed technology for the prediction of the transmission efficiency of the belts. As a result, it was found that when the fit clearance is reduced, the transmission efficiency of the belt is increased, and the amplitude of stress on the innermost rings and the element neck section is reduced. In addition, it was found that if pulley stiffness was reduced transmission efficiency was also reduced, and the amplitude of stress on the element neck section increased.
This indicated that the fit clearance and the pulley stiffness changed the degree of deflection of the pulleys in the axial direction. When the pulley deflection changes the winding diameter of the belt, the friction force on the V-surfaces of the elements approaches further in the direction of rotation, and transmission efficiency increases. In addition, the research also discovered that changes in the direct load on the element V-surfaces at the pulley exits affect the level of stress on the element neck sections. Changes in the degree of misalignment of the belt due to pulley deflection were also shown to affect the amplitude of stress on the rings.