Function-Optimized Disk Set Contour for Chain-CVT Torque Transmission
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Solution Overview
Problem
Existing disk sets with curved-surface and straight-surface disks face challenges in torque transmission, where curved-surface sets require less support but lead to increased tribological loading, and straight-surface sets require more support, affecting hydraulic system power requirements and efficiency.
Innovation Solution
A disk set arrangement with a function-optimized contour, featuring axially movable disks and a chain arrangement with rocker pins, where the curvature of the disks and rocker pins is determined by specific ratios of eccentricity and radius, optimizing the combination of curved and straight-surface features for reduced support and pressure, enhancing variator efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If curved-surface disk sets are used, then support requirements are reduced, but tribological loading increases
Solution Approach 1:
The disk surface is divided into different zones with different curvatures: an inner region with a first curvature radius and an outer region with a second curvature radius. This local differentiation allows the inner region to handle high torque with appropriate curvature while the outer region has reduced curvature to minimize tribological loading and support requirements.
Solution Approach 2:
The invention uses optimized curvature profiles on the disk surfaces, specifically varying the radius of curvature across different regions of the disk. The curvature is mathematically defined to achieve optimal contact conditions between the chain and disk, reducing both support requirements and harmful tribological effects simultaneously.
2Ease of manufacture
If straight-surface disk sets are used, then manufacturing is simplified, but support requirements increase and track displacement increases
Solution Approach 1:
Instead of using completely straight surfaces or complex curved surfaces throughout, the invention applies curvature only where necessary (inner region) while keeping the outer region with reduced curvature that is easier to manufacture. This localized application of complexity achieves the necessary performance while maintaining manufacturing feasibility.
3Ease of operation
If curved-surface disk sets are used, then track displacement is reduced, but the disk set angle changes with radius requiring complex chain contour adaptation
Solution Approach 1:
The invention optimizes the curvature parameters (radii of curvature in different regions) to achieve a compromise that reduces track displacement while limiting the change in disk set angle. The specific curvature values are selected to minimize both track displacement and the complexity of chain contour adaptation.
Data Source
AI summary
A disk set arrangement for a chain-CVT having a function-optimized disk set surface contour. The CVT includes a first drive disk set and a second driven disk set, wherein the disk sets of the disk set arrangement in each case include two disks mounted on respective shafts. One disk of each of the disk sets can be displaced axially relative to an opposed axially fixed disk. An endless chain arrangement with rocker pressure pieces is operative between the disk sets to transmit torque. The rocker pressure pieces have longitudinal axes that extend parallel to the rotational axes of the shafts, and include outer axial ends that contact the contoured disk surfaces.