Helical Gear Tooth Flank Layout for Quieter Meshing
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Solution Overview
Problem
Conventional gears experience stiffness fluctuations and noise due to meshing shocks during power transmission, leading to vibration stimulation, which is difficult to mitigate with precise and costly geometry corrections.
Innovation Solution
A gear design featuring tooth flanks with varying lengths, including crown and back-mounted tooth flanks, arranged orthogonally to the rotation axis, allowing for a helical gear configuration that reduces noise and vibration by altering the initial meshing behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional equidistant tooth spacing is used, then manufacturing is simpler, but meshing shocks and noise increase
Solution Approach 1:
The patent applies asymmetry by varying the tooth flank lengths in an asymmetric pattern around the gear circumference. Specifically, certain tooth flanks are extended while others are reduced, creating an asymmetric distribution that disrupts the periodic meshing shock pattern. This asymmetric tooth geometry modifies the meshing characteristics to reduce noise and vibration without requiring high-precision machining of each individual tooth.
Solution Approach 2:
The patent implements local quality by applying different tooth flank lengths to different locations around the gear. Instead of uniform tooth geometry, specific regions have extended tooth flanks while others have reduced flanks. This localized variation in tooth geometry allows the gear to exhibit different meshing characteristics at different positions, thereby reducing overall noise and vibration while maintaining manufacturability.
2Object-affected harmful factors
If precise geometry corrections are applied, then noise behavior improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent employs periodic action by creating a repeating pattern of extended and reduced tooth flanks around the gear circumference. This periodic variation in tooth geometry generates a meshing pattern that systematically reduces noise and vibration. The periodic structure allows for simpler manufacturing compared to completely asymmetric designs, as the pattern can be replicated using standard gear manufacturing processes with modified tool paths.
3Object-affected harmful factors
If tooth flank lengths are varied, then meshing shock is reduced, but manufacturing precision requirements change
Solution Approach 1:
The patent applies dynamics by introducing variability in tooth flank lengths to create a dynamic meshing pattern. Instead of static, uniform tooth geometry, the varying flank lengths create a dynamic interaction between meshing teeth that reduces shock loads. This dynamic approach allows the gear to adapt its meshing characteristics during operation, reducing harmful vibrations while maintaining reasonable manufacturing tolerances.
Data Source
AI summary
A gear for transmitting power has a plurality of teeth, each having two tooth flanks for transmitting power to another gear. The gear can be rotated about an axis of rotation, and has a reference plane, which is arranged orthogonal to the axis of rotation. Tooth flanks of the same name are the tooth flanks for transmitting power in one direction of rotation, wherein the tooth flanks have a tooth flank length proceeding from a front side of the reference plane. Two tooth flanks of the same name are arranged directly adjacent to a crown tooth flank, said two tooth flanks of the same name each having a smaller tooth flank length than the crown tooth flank. The gear has at least one of the crown tooth flanks and is configured as a helically toothed gear.