Randomized Chain Link Profiles for Noise Reduction
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Solution Overview
Problem
Existing chain and sprocket assemblies fail to effectively reduce operational noise caused by chordal action and regular timing of impact between the chain and sprocket, leading to undesirable oscillations and whine noise.
Innovation Solution
A chain and sprocket assembly with link plates having randomized profiles, where some link plates have a leading corner that interacts with a contact ring on the sprocket, delaying the impact between the link plates and the sprocket teeth, thereby breaking up the regular timing of impacts and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an additional contact surface is added to reduce chordal action, then noise from chordal action is reduced, but whine noise from regular timing of impact remains
Solution Approach 1:
The patent applies local quality by varying the link plate profiles at specific locations along the chain. Different link plates have different leading corner radii (e.g., some have 0.015 inch radius, others have 0.030 inch radius), creating localized variations in the chain-sprocket interaction. This local variation disrupts the regular timing of impacts while maintaining the overall chain function, thereby reducing whine noise without compromising chordal action reduction.
Solution Approach 2:
The patent implements dynamics by introducing variability and randomness into the link plate profile sequence. Rather than using uniform link plates, the chain incorporates a randomized sequence of different link plate profiles, making the chain-sprocket interaction dynamic and non-repetitive. This dynamic variation breaks up the regular impact timing that causes whine noise, while the additional contact surface continues to reduce chordal action.
2Object-affected harmful factors
If link plates with leading corners are used to delay impact, then operational noise is reduced, but chain complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the link plates, specifically the leading corner radius. By varying this parameter (creating different link plate profiles with different radius values), the patent achieves noise reduction through delayed and varied impact timing. Despite this increased geometric complexity, the patent maintains manufacturing feasibility by using a limited set of standardized profiles (e.g., two or three different radius values) that can be produced with conventional machining processes.
Data Source
AI summary
A chain and a chain and sprocket assembly for a roller, bush, or inverted tooth chain is disclosed. The chain has at least two types of link plates having different profiles, with at least one type of link plate having a leading corner for interaction with a contact ring on the sprocket, thereby reducing noise by reducing chordal action and by breaking up the regular timing of roller-sprocket (or bushing-sprocket) and link plate-sprocket impact. A method of reducing noise in a chain and sprocket assembly is also disclosed.