CVT Drive Belt Transverse Segment Offset to Reduce Radial Sliding
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Solution Overview
Problem
The existing drive belts with transverse segments in continuously variable transmissions experience radial sliding between segments, leading to increased friction and wear, which affects torque transmission and generates noise during operation.
Innovation Solution
The transverse segments are arranged in a backwards inclined position by positioning the protrusion lower on the segment, with the protrusion's centreline radially inward of the cavity's centreline, reducing radial sliding and increasing tangential friction with the pulley, thereby enhancing torque transmission and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transverse segments are arranged in a straight position, then the structure is simple and manufacturing is easy, but radial sliding occurs between segments causing increased friction and wear
Solution Approach 1:
The transverse segments are arranged in an asymmetric backwards-inclined configuration rather than a straight symmetric arrangement. The protrusion and cavity are positioned with an offset in the radial direction, creating an asymmetric geometry that forces the segments into a backwards-inclined position. This asymmetric arrangement eliminates radial sliding between segments while maintaining reliable torque transmission.
2Power
If normal force between drive belt and pulleys is increased, then torque transmission is improved, but frictional losses and wear increase
Solution Approach 1:
The invention changes the geometric parameters of the transverse segment arrangement by introducing a backwards inclination angle. This parameter change modifies the contact mechanics between segments and their interaction with the pulley, enabling torque transmission with reduced normal force requirements. The altered geometry reduces frictional losses while maintaining effective power transmission.
3Productivity
If transverse segments enter the pulley abruptly, then torque transmission is immediate, but noise is generated
Solution Approach 1:
The backwards inclination of the transverse segments creates a gradual curved entry path into the pulley rather than an abrupt angular contact. This curved geometry allows the segments to enter the pulley smoothly, reducing impact noise while maintaining continuous torque transmission. The inclination angle optimizes the transition from straight belt section to pulley contact.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for higher torque transmission with reduced normal force between the drive belt and pulleys and decreases noise by up to 10 dB, as the segments enter the pulley more gradually, minimizing radial sliding and frictional losses.
Implementation Method 1
radial sliding between segments, leading to increased friction and wear
Implementation Method 2
increasing tangential friction with the pulley, thereby enhancing torque transmission
Data Source
AI summary
Transverse segments (10) for a drive belt (6) for a belt-and-pulley-type continuously variable transmission include a row of these transverse segments (10) mounted on a stack (9) of several, mutually nested rings. The transverse segments (10) are provided with a protrusion (40) that protrudes from a front surface (11) thereof and with a corresponding cavity (41) that is provided in a back surface (12) thereof. An offset is provided between the protrusion (40) and the cavity (41) in the radial direction of the drive belt (6), such that in the row of transverse segments (10) in the drive belt (6) these will be inclined backwards by the forced insertion of the protrusion (40) into the cavity (41).