Misalignment equation for the Van Doorne metal pushing V-belt continuously variable transmission

Abstract

The existence of belt=pulley misalignment in the Van Doorne metal pushing V-belt continuously variable transmission (CVT) has always been recognized by researchers and the manufacturers themselves. However, its effect has always been assumed to be negligible and search through the literature reveals no work published so far to verify this assumption. Misalignment of the belt may increase losses and the need to improve efficiency is now of paramount importance. This paper is an initial effort by the authors to address this area and study the geometrical behaviour of the belt misalignment theoretically. An equation to represent this geometrical behaviour has been developed and it is able to calculate the magnitude and position of the belt misalignment at different speed ratios and at different assembled zero belt misalignment speed ratios. The condition necessary to minimize the magnitude of the belt misalignment has been determined. Verification of the equation was obtained by using a solid modeller from a Unigraphics Version 10.4.0 computer aided design (CAD) package. It is intended that the findings from this study will enable the authors to study further the effect of misalignment on the efficiency and performance of the transmission.

Design of Electro-Mechanical Dual-Acting Pulley Continuously Variable Transmission

“…Hence, the V-belt's misalignment is inevitable in the existing pulley-based CVT with a single-acting pulley system. Studies by some previous researchers suggest that V-belt misalignment causes sinusoidal stresses and transverse forces on the V-belt's band and elements respectively, which reduces the efficiency of (a) (b) (c) the CVT while at the same time also decreasing the lifespan of the V-belt [7,8,16]. With the dual-acting pulley system of EMDAP CVT, the misalignment of the V-belt is reduced significantly; hence the efficiency of the CVT and the lifespan of the V-belt can be increased.…”

“…With this system, only one half of the pulley sheave is moved axially during the event of changing the CVT ratio. Previous researchers suggest that the single-acting pulley system leads to misalignment of the Vbelt during operation [7,8]. The V-belt used in the existing pulley-based CVT consists of two main components, namely the bands and the elements, as shown in Figure 1 [9].…”

“…The V-belt used in the existing pulley-based CVT consists of two main components, namely the bands and the elements, as shown in Figure 1 [9]. Previous researchers suggest also that V-belt misalignment causes sinusoidal transverse stresses on the V-belt's bands, which could eventually reduce the lifespan of the V-belt [7,10]. Not only that, it could also reduce the V-belt's tension during operation, and hence decrease the efficiency of the CVT.…”