Development of Metal Pushing V-Belt for Continuously Variable Transmission - Investigation for Clearance Between Elements, Strength of Element and Strength of Ring Material

HONDA completed research and development of the Metal V-Belt for CVTs in-house for the purpose of reducing the minimum pitch radius. The newly developed belt is essential to the compactness of a CVT and increases the speed ratio range. Increase of ring stress caused by reducing the minimum pitch radius is treated by improvement of element shape, optimizing clearance between elements and between element and ring and improving materials.⁽¹⁾ In this paper, the optimization of clearance between elements, heat treatment of elements and optimization of ring material are described in detail.

Optimum total clearance between elements for a virgin belt is defined by test results during operation using a specially engraved gap sensor and a telemeter system. Tolerance and conditions of heat treatment for elements are optimized concerning fatigue strength of the element nose. Inclusions in material are decreased and temperature of solution treatment is optimized to increase fatigue strength of rings.