Hot Keywords:
- All
- Product Name
- Product Keyword
- Product Model
- Product Summary
- Product Description
- Multi Field Search
Views: 0 Author: Site Editor Publish Time: 2026-02-13 Origin: Site
Position: Centered on the tooth flank, slightly offset toward the meshing-in end.
Shape: A regular ellipse or rhombus for spur gears; a diagonal band for helical gears.
Size: Covers 30%-50% of the tooth height and 60%-80% of the tooth length (specific values subject to application standards).
Contour: Uniform impression with no breaks and clear edges.
Ideal condition: Load is evenly distributed along the theoretical contact line, resulting in small and smooth transmission error (the deviation between the actual and ideal position of the output shaft).
Non-ideal contact patch: A skewed, undersized, or abnormally shaped contact patch indicates localized load concentration on a small area of the tooth flank.
Consequence: This causes uneven elastic deformation of the tooth profile and gear body, significantly increasing transmission error—the primary internal excitation source of gear systems. Its periodic variation directly excites gear vibration and radiated noise.
Meshing impact: If the contact patch is missing or overly weak at the addendum or dedendum, a severe meshing-in impact occurs when one gear pair finishes meshing and the next engages, due to the lack of sufficient guidance and buffering. This impact produces high-frequency "clicking" or knocking sounds.
Time-varying meshing stiffness: Gear meshing stiffness changes periodically with the number of meshing tooth pairs. An unhealthy contact patch exacerbates this stiffness fluctuation, generating stronger stiffness excitation and causing mid-to-low frequency "hum" noise.
Phenomenon: Edge contact occurs when the contact patch touches or extends beyond the tooth flank edges (e.g., addendum, dedendum, or end face).
Consequence: Edge contact is synonymous with high stress concentration. It not only increases contact stress, leading to early pitting or tooth breakage, but also generates abnormally intense dynamic excitation, typically manifesting as a harsh "squeal" or "creak".
| Contact Patch Morphology | Possible Causes | Impacts on Meshing | Typical Noise Characteristics |
|---|---|---|---|
| Upper offset (near addendum) | Excessive center distance, oversize tooth profile crowning, non-parallel gear axes (skew) | Prone to addendum edge contact and high meshing-in impact | High-frequency knocking and squealing |
| Lower offset (near dedendum) | Insufficient center distance, improper tooth profile modification | Prone to dedendum edge contact and high meshing-out impact | High-frequency knocking and dull impact noise |
| End offset (tooth direction load eccentricity) | Non-parallel gear axes, skewed gearbox housing bores, shaft bending deformation | Load concentration, severe local stress, significant transmission error | Periodic "rumble" with intense vibration |
| Narrow/interrupted patch | Oversize tooth profile crowning, high tooth flank waviness, large pitch error | Reduced effective bearing area, lower contact ratio, severe load fluctuation | Broadband "hissing" or white noise with irregular knocking |
| Diagonal contact (helical gears) | Crossed gear axes (non-coplanar in vertical direction), helix angle error | Dangerous line contact, extremely high stress, severe sliding |
