Novel RADIALcvt Simulation and Test Results

The RADIALcvt is a traction drive continuously variable transmission (CVT) implemented in a new novel radial configuration mechanical assembly. The RADIALcvt functions as a multi-parallel power path (at least six) type of CVT, which consists of only one steel-on-steel, line contact, traction drive interface in each power path. A constant input radius on the traction drive input makes it possible to use a constant clamping force which is provided by mechanical springs, thus eliminating the need for a hydraulic control system. The RADIALcvt has a very large radius variation on the traction drive output which provides the ratio variation. The fact that the RADIALcvt input traction rollers are clamped between two opposite rotating disks results in a clamping force which is about 50% of the equivalent clamping force of a typical traction drive CVT. This paper presents the basic mechanical configuration of the first prototype, a traction drive simulation as well as the test results of the first prototype to include measured values of mechanical efficiency, slip and traction curves at different speeds and loads. The first prototype presents mechanical efficiencies above 90% while providing excellent partial load versus mechanical efficiency properties.