EFFECT OF MESHING TOOTH STIFFNESS AND MANUFACTURING ERROR ON THE ANALYSIS OF STRAIGHT BEVEL GEARS

A procedure for calculating transmitted load distribution along face w idth as well as tooth stresses of straight bevel gears is introduced. The procedure is based upon the Tredgold assumption, which assumes tha t a straight bevel gear, when projected on a plane tangent to the back cone, can be approximated as a spur gear having a pitch radius equal to the back-cone radius and same pitch as the bevel gear. To increase the solution accuracy, the bevel gear is divided into a number of spur gears by a finite number of slicing planes that are parallel to the p lane of projection. Each slice is then analyzed as a separate spur gea r, and tooth stiffness, load, and stresses are determined separately. As a result, the load and stress distribution for the actual bevel gea r are obtained. The procedure assumes that the sum of tooth deflection , profile modification, and manufacturing errors at the pairs of conta cting slices of the pinion and gear are all equal, in order to avoid o verlap and tooth interference. It is also assumed that the sum of the normal loads contributed by each pair of contacting slices is equal to the total normal load on the entire bevel gear, which is obtainable f rom the transmitted power/torque. Once the normal loads for all slices representing the bevel gear are determined, fillet and Hertzian stres ses are calculated from the applied loads and slice geometry, Conseque ntly, the distribution of such stresses for the actual bevel gear are also calculated. An example is presented to explain the criterion. Exp erimental substantiation, using strain gauge measurements, is also pre sented to demonstrate tile validity of the criterion.