Segmented Pulley Support Structure for Stable Ratio Changes Under Load
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Solution Overview
Problem
Clutchless multi-ratio transmissions face challenges in functioning effectively at high speeds or under significant loads due to issues like ratcheting, slippage, and tensioning, which affect their reliability and efficiency, limiting their commercial viability.
Innovation Solution
A segmented pulley transmission system with pulley segments that can transition between engaged and disengaged regions, featuring integrated supports to manage the endless member's bending and slack, and an actuator to move segments between these states, ensuring stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If clutchless multi-ratio transmissions are used to change ratio under load, then transmission functionality is improved, but mechanical problems such as ratcheting, slippage, and tensioning occur that reduce reliability and efficiency
Solution Approach 1:
The pulley is divided into multiple independently actuatable segments that can be selectively engaged or disengaged from the endless drive member. This segmentation allows the transmission to maintain continuous engagement through multiple segments, preventing ratcheting and slippage while enabling ratio changes under load without compromising reliability.
2Adaptability or versatility
If pulley segments are individually actuatable to change ratio, then transmission adaptability is improved, but tensioning problems and wear increase that reduce efficiency
Solution Approach 1:
The pulley segments are actuated into or out of engagement before the endless drive member enters or exits the contact zone. This preliminary action ensures smooth transitions without sudden tension spikes, reducing wear and energy loss while maintaining the ability to change ratios under load.
3Reliability
If segmented pulley transmission is used to prevent ratcheting and slippage, then reliability is improved, but device complexity increases
Solution Approach 1:
Multiple pulley segments are nested concentrically around a core pulley, with each segment capable of independent actuation. This nested configuration allows the system to achieve high reliability through multiple engagement points while maintaining a compact structure that doesn't proportionally increase overall complexity.
Data Source
AI summary
A segmented pulley defining an outer peripheral surface for engaging an endless member of a segmented pulley transmission is provided. The segmented pulley comprises: a plurality of pulley segments configured to be sequentially movable between an engaged region and a disengaged region to transition the endless member between the segmented pulley and a concentric pulley in the segmented pulley transmission, each of the pulley segments having a body defining a portion of the outer peripheral surface. The plurality of pulley segments includes a transition segment having an integrated support extending from the body of the transition segment, the integrated support being configured to support the endless member when transitioning the endless member between the segmented pulley and the adjacent pulley in the segmented pulley transmission. A segmented pulley transmission comprising the segmented pulley is further provided.