Non-Uniform Sprocket Tooth Phasing for Chain Noise Suppression
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Solution Overview
Problem
Existing sprockets fail to effectively mitigate noise and vibration caused by load torque fluctuation, phase deviation, and resonance, leading to increased tension fluctuation and order noise.
Innovation Solution
The sprocket design features non-uniformly arranged teeth with specific angular phases (θ+1.5°≥θn≥θ+0.1° and θ−0.1°≥θn≥θ−1.5°) to deviate load torque fluctuation cycles, suppress order noise, and prevent resonance, with optional sintered material and varying pitch circle diameters for enhanced noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If teeth are arranged with non-uniform angular phases to mitigate tension fluctuation, then noise and vibration are suppressed, but order noise corresponding to the fluctuation cycle may still occur
Solution Approach 1:
The patent applies asymmetry by arranging teeth with non-uniform angular phases, where each tooth's angular phase θn deviates from the uniform phase θ in an asymmetric pattern. This asymmetric arrangement disrupts the periodicity of tension fluctuation, thereby suppressing both general noise/vibration and order noise corresponding to the fluctuation cycle.
Solution Approach 2:
The patent changes the angular phase parameter θn of each tooth from a uniform value θ to non-uniform values within specific ranges (θ+1.5°≥θn≥θ+0.1° and θ−0.1°≥θn≥θ−1.5°). This parameter modification alters the tension fluctuation characteristics, effectively suppressing noise and vibration while preventing order noise.
2Reliability
If the phase of load torque fluctuation deviates or resonance occurs, then tension fluctuation may increase instead of being suppressed
Solution Approach 1:
The patent applies preliminary anti-action by pre-arranging teeth with non-uniform angular phases before operation. This pre-configured arrangement creates a phase difference that counteracts the load torque fluctuation in advance, preventing tension fluctuation increase even when phase deviation or resonance occurs during operation.
Solution Approach 2:
The asymmetric angular phase arrangement creates a mismatch between the tooth engagement pattern and the load torque fluctuation cycle, preventing synchronous resonance and phase-aligned tension peaks, thereby maintaining reliable tension suppression under varying operating conditions.
3Ease of manufacture
If teeth are arranged uniformly, then manufacturing is simple, but noise and vibration cannot be effectively suppressed
Solution Approach 1:
The patent modifies the angular phase parameter θn from a uniform value to non-uniform values within controlled ranges. This parameter change can be implemented through standard manufacturing processes with adjusted positioning, maintaining ease of manufacture while effectively suppressing noise and vibration through the non-uniform arrangement.
4Reliability
If larger angular phase deviations are used, then tension fluctuation is reduced, but order noise and vibration increase
Solution Approach 1:
The patent optimizes the angular phase deviation parameters by constraining θn within specific ranges (θ+1.5°≥θn≥θ+0.1° and θ−0.1°≥θn≥θ−1.5°). This controlled parameter change achieves sufficient tension fluctuation mitigation while limiting the deviation magnitude to prevent excessive order noise and vibration.
Solution Approach 2:
The patent applies local quality by making each tooth's angular phase θn unique within the specified ranges, creating a localized non-uniform pattern that effectively disrupts tension fluctuation cycles without generating excessive order noise, balancing tension mitigation and noise control.
Data Source
AI summary
Provided is a sprocket that mitigates the influence of tension fluctuation corresponding to load torque fluctuation, suppresses the occurrence of order noise corresponding to the cycle of the load torque fluctuation while suppressing noise and vibration, and prevents an increase in the tension fluctuation as well as an increase in the noise and vibration caused by resonance. A plurality of teeth meshing with a chain are arranged such that an adjacent angular phase θn of each of the plurality of the teeth is non-uniform. In a case where an angular phase obtained when all the teeth are arranged in a uniform angular phase is defined as θ (360°/the number of teeth), the adjacent angular phase θn of each of the teeth includes a site where θ+1.5°≥θn≥θ+0.1° and a site where θ−0.1°≥θn≥θ−1.5°.