Segmented Pulley Supports for Smooth 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 with integrated supports on pulley segments that extend beyond the outer peripheral surface, providing physical support to adjacent segments and controlling slack in the endless member, allowing smooth transitions between pulleys without interrupting operation under load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If clutchless multi-ratio transmissions operate at high speeds or under significant loads, then power transmission capability is improved, but mechanical problems such as ratcheting, slippage, and tensioning increase
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 smooth ratio changes without interrupting power transmission, preventing ratcheting and slippage during transitions while maintaining high power transmission capability under load.
Solution Approach 2:
The transmission system employs dynamic actuation of pulley segments where segments can be moved into or out of engagement with the endless drive member during operation. This dynamic adjustment enables continuous ratio changes without interrupting power flow, eliminating ratcheting effects and maintaining reliability under significant loads.
2Adaptability or versatility
If pulley segments are actuatable into and out of engagement, then ratio change capability is improved, but ratcheting and slippage problems increase
Solution Approach 1:
Pulley segments are actuated into or out of engagement before the contact zone where power transmission occurs. This preliminary action ensures that segment engagement/disengagement happens in advance, preventing ratcheting and slippage during the actual power transmission phase while maintaining full ratio change capability.
Solution Approach 2:
The transmission system maintains continuous power transmission during ratio changes by ensuring that pulley segments are actuated outside the contact zone. This continuity prevents interruptions, ratcheting, and slippage, allowing seamless ratio transitions that maintain both adaptability and reliability.
3Adaptability or versatility
If pulley segments are actuated during operation, then multi-ratio functionality is improved, but tensioning problems and wear increase
Solution Approach 1:
All actuation of pulley segments occurs in advance, outside the contact zone, before power transmission begins. This preliminary positioning ensures that segments are already in their correct engagement state when power transmission starts, eliminating tensioning problems and reducing wear during operation while maintaining full multi-ratio functionality.
Solution Approach 2:
By maintaining continuous engagement of properly positioned pulley segments during power transmission, the system avoids the tensioning fluctuations and impact loads that cause wear. The continuous action ensures smooth power transfer across all ratios, reducing mechanical wear while preserving adaptability.
Data Source
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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.