Variable-Wavelength Sprocket Layout for Chain Noise and Vibration
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Solution Overview
Problem
Existing sprockets fail to effectively suppress order sounds, tension fluctuations, noise, and vibrations caused by load torque fluctuations and resonance, despite attempts to alleviate tension fluctuations through phase fluctuation patterns.
Innovation Solution
A sprocket with teeth arranged to form a phase fluctuation pattern of varying wavelengths, where the phase fluctuates between positive and negative sides, and the wavelength changes continuously from long to short or vice versa, aligning with or differing from the load torque fluctuation cycles to prevent resonance and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a phase fluctuation pattern with constant wavelength is used to alleviate tension fluctuations, then noise and vibrations are suppressed, but order sounds corresponding to load torque fluctuation cycles are unavoidably generated
Solution Approach 1:
The patent applies local quality by varying the wavelength of the phase fluctuation pattern at different locations around the sprocket circumference. Different segments of the sprocket have different wavelength characteristics, which allows the phase fluctuation to effectively counteract tension fluctuations while avoiding periodic order sounds. This is achieved by making the phase fluctuation wavelength a variable parameter rather than a constant, thereby creating non-uniform local characteristics that prevent repetitive noise patterns.
Solution Approach 2:
The patent implements preliminary action by pre-designing the phase fluctuation pattern with varying wavelengths before the sprocket operates. The phase fluctuation is built into the tooth arrangement configuration in advance, so that when the chain engages with the sprocket teeth, the tension fluctuations are already being counteracted by the pre-established phase variation. This prevents the generation of order sounds before they can occur during operation.
2Reliability
If the phase in load torque fluctuations shifts or resonance occurs, then tension fluctuations increase, but using a fixed phase fluctuation pattern cannot adapt to changing operating conditions
Solution Approach 1:
The patent applies dynamics by creating a phase fluctuation pattern that inherently adapts to changing operating conditions through its varying wavelength structure. As the sprocket rotates and different wavelength segments engage with the chain, the phase fluctuation characteristics automatically adjust to counteract shifting load torque patterns and avoid resonance conditions. This dynamic adaptation is built into the geometric configuration of the tooth arrangement rather than requiring external control systems.
Solution Approach 2:
The patent implements parameter changes by varying the wavelength parameter of the phase fluctuation pattern around the sprocket circumference. This creates a non-uniform distribution of phase fluctuation characteristics that can adapt to different operating conditions. When load torque fluctuations shift phase or resonance occurs, the varying wavelength structure ensures that the phase fluctuation effectively counteracts tension fluctuations across different rotational positions and operating states.
Data Source
AI summary
Provided is a sprocket which suppresses generation of order sounds corresponding to cycles and prevents increase in tension fluctuations, noise, and vibrations caused by resonance while alleviating the influence of the tension fluctuations corresponding to load torque fluctuations and suppressing noise and vibrations. A plurality of teeth formed to engage with a chain are arranged to form a phase fluctuation pattern of a waveform having a phase which fluctuates between positive and negative sides, and the phase fluctuation pattern is set to have parts having different wavelengths.