Search results for "V-belt"
showing 4 items of 4 documents
A new approach to the design of a speed-torque-controlled rubber V-belt variator
2005
This paper presents a new model for a torque-speed-sensing rubber V-belt variator. The actuators are of the centrifugal roller kind on the driver side and a helical torque cam plus a compression-torsion spring on the driven side. The equations permit designing the actuator geometry in order to keep the transmissible torque as close as possible to the torque request in the whole operative field. Moreover, a procedure is suggested for the most proper design of an automatic variator of this kind. It permits choosing the required variogram of the transmission, i.e. the matching between the engine and the transmission, and designing the actuators: roller mass, housing shape, contact plate angle…
V-Belt Winding along Archimedean Spirals During the Variator Speed Ratio Shift
2010
Starting from a previous model for the shift mechanics of rubber belt variators, this lecture elaborates practical design formulas for the torque and the axial thrust making use of the very close resemblance of the belt path to a linear spiral of Archimedes along a large part of the arc of contact. In addition, as an alternative to the modern calculus tools, it is shown how the drive variables can be equally calculated applying some propositions of Archimedes’ classical treatise πeρί ‘eλίκων (On Spirals).
Joint Influence of Transverse Compression and Shear-Flexural Stiffness on Rubber V-Belt Mechanics
2009
The elasto-mechanical behavior of a rubber V-belt in the neighborhood of the seating and unseating regions of the pulley is affected by the transverse belt compliance, which produces a gradual radial penetration into the groove and by the shear-flexural deformation, which arches the belt line along the free strand away from the ideal straight path. These effects are always analyzed separately in the literature, but are in close correlation with each other. This lecture describes the matching between the free strand and the wrap region, showing a remarkable reduction of the belt arching and of the contact losses, with respect to the conventional theory.
A Two-Dimensional Approach to Rubber V-Belt Mechanics
2010
A new two-dimensional approach to the mechanics of rubber V-belt CVT's takes into account the change, along the belt sides, of the sliding velocity on the pulley walls, together with the cross section rotation due to the shear forces. The results show significant differences with the one-dimensional thin belt model and point out the gradual increase or decrease of the belt curvature in the entrance and exit regions of the contact arc, which implies the negligibility of the belt arching in the free spans. Some experimental tests on the global variables of a rubber belt CVT indicate a very fine acceptability of the theoretical model.