Practical methods to control gear whine in transmission manufacturing process
Gear whine of automotive transmissions should be controlled since it is of a nuisance. While many methods are used to control gear whine at gear design stage, this paper deals with it in transmission manufacturing process including gear manufacturing and transmission assemblies. There are high percentages of effects on transmission error and gear whine in these two processes. Idle gear whine noise can be reduced by the introduction of hard finishing which can optimize the gear shapes and surfaces. Bending of helical gear is found playing an important role in generating high frequency gear whine. It is significant for transmission assemblies to study the correlations of End of Line (EOL) and vehicles. The satisfying correlations can identify and control gear whine of an assembled transmission. All the methods mentioned above have been applied in transmission manufacturing process and good results have been achieved.
Optimum Profile Modifications for the Minimization of Static Transmission Errors of Spur Gears
A procedure for computing static transmission errors and tooth load sharing was developed for low and high contact ratio internal and external spur gears. A suitable optimization algorithm was used to minimize any combination of the harmonics of gear mesh frequency components of the static transmission error. Different combinations of tip and root relief may be used to achieve optimization. These include varying the starting point of relief and varying the magnitude of relief, and selecting the gear and/or the pinion teeth to be tip and/or root-relieved. Also, there exists an option for using either linear or parabolic relief. In addition to the presentation of optimal profile modifications, the effects of off-design loads, nonoptimum modifications, and random spacing errors are presented.
Gear-tooth Stresses and Rating Formulae
The state of knowledge about stress conditions in gear teeth is briefly reviewed, and directions in which further research is required are indicated. The assumptions underlying methods of stress-comparison, and the chosen load-points, are considered in relation to profile-modification, leading to revised conceptions of “precision” and “commercial” classes of gear. The present (British standard) basis for the design of “commercial” teeth is stated and a new basis for the design of precision, high-duty gears is offered.Criteria of surface stress are re-examined and current British standard rating formulae for wear are shown to be equivalent to the use of an unmodified criterion Sc = Fc/Rr in conjunction with a speed factor which is a function of pitch circle velocity and gear ratio. New values for zone factors and strength factors for spur gears have been determined on the revised assumptions, and it is shown how the factors for helical teeth may be derived from those for the virtual spur gears. The assumpt...