Technical Articles

How to Reduce the Noise of Gear in Metal Processing

Posted: 2014-07-02 23:11:09  Hits: 1593
In order to avoid the reducer failing the factory test, intermittent high noise should be reduced. A low noise reducer is 72.3 Db (A) tested by ND6 precision sound level meter, which meets the requirements of factory. While high noise reducers with 82.5 dB (A) can’t pass factory tests. It is indispensable that manufacturers should carry out integrated management during each production link to effectively reduce the noise of gear transmission.

1. Control the precision of gears

It has been verified by practice that gear precision must be controlled at Level GB10995-887-8. The gear linear velocity should be higher than 20 m/s. Pitch limit deviation, run-out tolerance of ring, and tooth tolerance must stably reach Level 7.

2. Control the quality of raw materials. 

High quality raw material is a prerequisite for high quality products. Whatever the approach is, raw materials must be taken strict chemical composition inspection, grain size determination and purity assessment. Its purpose is to timely adjust the heat treatment deformation and improve the quality in tooth profile processing.

3. Prevent heat treatment deformation.

Gear billets are forming as precision forgings after rough machining. Then conduct normalizing or conditioning treatment in order to:
(1) Soften steel for machining;
(2) Eliminate residual stress;
(3) Refine grains and perfect structure in order to improve the mechanical properties of steel;
(4) Prepare for the final can handle. 

4. Ensure the accuracy of gear billets.

The precision of gear hole size should be about ±0.003~±0.005mm. If the number is out of tolerance but within the design scope of the hole, the gears should be classified and respectively gone into gear cutting process.

5. Measures of gear cutting processing.

Out-sourcing gear cutting tools must be tested and meet the requirements of AA. Cutting tool front blades radial property, adjacent pitch of chip pocket, the maximum accumulation error of chip pocket and the parallelism of front blade and inner hole axis should be tested after sharpening. Improve the addendum coefficient by 0.05-0.1m and avoid the interference between tooth roots.

6. Conduct civilized production.

More than 30% of gear transmission noise is from burr and knocking. 
(1) For gear shaft parts, put special plastic cases on gear tools after hobbing and transfer to the next procedure. Operate storage and shipment with the protective cases.
(2) Implement gear honing process to reduce the tooth surface roughness and deburr to prevent knocking.

7. Adopt other materials, heat treatment and surface treatment ways.

(1) Use powder metallurgy forming technology and conduct high frequency quenching after forming.
(2) Use graphite cast iron and conduct tufftriding process after cutting.
(3) Use 40Cr materials and conduct tufftriding or coppering after cutting.

Miss Lavendie Lee 
Tel: +86 511 84514398 
Fax: +86 511 85347508
Cell: +86 13775559804 
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