CVT Belt Ring Layout for Larger Pulley Winding Radius
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Solution Overview
Problem
Conventional continuously variable transmissions have limitations in increasing the speed ratio range, as they do not provide a specific means to enhance the maximum winding radius of the metal V-belt around the drive and driven pulleys.
Innovation Solution
A continuously variable transmission design that includes a transmission belt with elements having a body portion and pillar portions, where the ring is disposed between the pillar portions and protrudes radially outward when the pulley groove is at its minimum width, preventing the ring from coming off and increasing the maximum winding radius.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the maximum winding radius of the transmission belt is increased to expand the speed ratio range, then the speed ratio range is improved, but the structural design becomes more complex
Solution Approach 1:
The transmission belt is divided into multiple elements, each comprising a body portion and pillar portions. The ring is segmented to fit between the pillar portions, allowing the belt to achieve a larger effective winding radius while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The ring is designed to protrude radially outward from the pulley groove surface in the thickness direction, utilizing the radial dimension to increase the effective winding radius. This dimensional approach allows expansion of the speed ratio range without proportionally increasing overall structural complexity.
2Adaptability or versatility
If the ring protrudes radially outward beyond the pulley groove to increase winding radius, then the speed ratio range is improved, but the risk of the ring coming off increases
Solution Approach 1:
The ring is nested between the pillar portions of adjacent elements, with the pillar portions acting as retaining structures. This nested configuration allows the ring to protrude radially outward for increased winding radius while the pillar portions prevent the ring from coming off, simultaneously achieving both objectives.
Solution Approach 2:
The pillar portions serve as intermediary structures between the ring and the elements. They provide the retaining function to prevent ring detachment while allowing the ring to maintain its protruding position for increased winding radius, mediating between the conflicting requirements of retention and radius expansion.
Data Source
AI summary
A continuously variable transmission includes a transmission belt including a plurality of elements and a ring and wound around V-grooves of first and second pulleys, each of the plurality of elements including a body portion having a saddle surface and a pair of pillar portions extended from the body portion so as to be located on both sides in a lateral direction of the saddle surface, and the ring being disposed between the pair of pillar portions of each of the plurality of elements. When one of the first and second pulleys has its minimum groove width, at least a part in a thickness direction of the ring wound around the one of the first and second pulleys protrudes radially outward beyond an outermost circumference of a surface of the V-groove of the one of the first and second pulleys.