Irregular Gear Tooth Geometry for Tonal Noise Suppression
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Solution Overview
Problem
Conventional gear drives are ineffective in reducing tonal noise while maintaining load-bearing capacity, leading to customer complaints about gear whine noise, which is particularly annoying due to its periodic nature.
Innovation Solution
The introduction of a toothed machine element with varying geometry parameters such as pressure angle and tooth scaling along the circumference, allowing for irregular tooth arrangements that break the periodicity of noise excitation, thereby reducing tonal noise across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional regular tooth arrangement is used, then load-bearing capacity is maintained, but tonal noise (gear whine) is generated
Solution Approach 1:
The patent applies asymmetry by varying the tooth thickness across different teeth in the gear. Specifically, at least one tooth has a different tooth thickness compared to other teeth, creating an asymmetric tooth arrangement that disrupts the periodicity of meshing noise while preserving load-bearing capacity through careful design of the thickness variations
Solution Approach 2:
The patent implements local quality by applying different tooth thicknesses to specific teeth rather than uniformly across all teeth. This allows localized modification of noise characteristics while maintaining overall gear strength, with each tooth potentially having optimized dimensions for its specific position and function
2Object-affected harmful factors
If irregular tooth arrangement is introduced to reduce tonal noise, then noise periodicity is broken, but gear meshing regularity may be affected
Solution Approach 1:
The patent applies parameter changes by systematically varying the tooth thickness parameter across different teeth. This controlled variation in a key geometric parameter disrupts noise periodicity while maintaining meshing regularity through careful selection of thickness values that ensure proper engagement and disengagement of tooth pairs
Data Source
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Figure 3A
AI summary
A toothed or structured machine element (100), in particular a gearwheel, for transmitting rotational movements comprises a peripheral tooth system (110) having a plurality of tooth elements in order to engage with a further toothed or structured machine element (200) and thereby to permit the transmission of the rotational movement to the further machine element. The plurality of tooth elements are characterized by geometry parameters (α, S) and at least one tooth element from the plurality of tooth elements differs in at least one of the following geometry parameters from other tooth elements from the plurality of tooth elements: an engagement angle (α), and a tooth scale (S).