Gear Tooth Lead Crowning for Misalignment Compensation
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Solution Overview
Problem
Gear trains with parallel-axis gearing in the automotive industry face misalignment issues due to loose fit and clearance, leading to suboptimal gear meshing events, noise, and vibration under high torque loads.
Innovation Solution
A parallel-axis gear configuration with lead crowning on gear teeth, featuring distinct drop-off magnitudes in first and second lead crowns, and a chemical vapor deposit coating like BALINIT® C Star, helps in reducing noise and vibration by inhibiting micro-welding and improving load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If gear alignment is controlled by fit and clearance between housing and gears, then assembly is simplified, but gear meshing quality deteriorates under high torque loads
Solution Approach 1:
The patent applies lead crowning - a localized modification to the gear tooth surface geometry - to compensate for misalignment. The crowning creates a specific curvature pattern on the tooth face that redirects contact stresses to the central region of the tooth, thereby maintaining optimal meshing conditions despite variations in gear alignment caused by assembly tolerances.
2Ease of manufacture
If standard gear teeth geometry is used, then manufacturing is simpler, but noise and vibration increase under high torque loads
Solution Approach 1:
The patent introduces lead crowning which adds a curved surface geometry to the gear teeth. This curvature modification changes the contact pattern from linear to distributed across the tooth face, smoothing out impact loads and reducing the generation of noise and vibration during gear operation under high torque conditions.
3Stress or pressure
If gear teeth have uniform load distribution, then stress is reduced, but misalignment compensation capability is lost
Solution Approach 1:
The lead crowning creates a non-uniform load distribution pattern intentionally - concentrating contact stresses toward the center of the tooth face while reducing edge loading. This localized stress redistribution serves dual purposes: it compensates for misalignment effects and simultaneously reduces overall tooth stress, improving both adaptability and strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The described configuration enhances consistent gear meshing, reduces noise and vibration (NVH), and compensates for misalignments, while the chemical vapor deposit coating further minimizes friction and micro-welding, leading to improved performance and reduced noise levels.
Implementation Method 1
The first gear can include a chemical vapor deposit coating thereon. The chemical vapor deposit can be BALINIT® C Star coating.
Data Source
AI summary
A parallel axis gear configuration constructed in accordance to one example of the present disclosure can include a first gear having a first gear tooth that includes a lead crowning across a face width thereof. The lead crowning can include (i) a first lead crown defined from a centerline to a transition point and (ii) a second lead crown defined from the transition point to a first end point. The lead crowning can include a drop-off magnitude that is greater at the second lead crown than the first lead crown.