Computerized design and generation of spiral bevel gears and forged straight bevel gears with improved geometry

The objective of this investigation is the computerized design, generation and analysis of the low-noise spiral bevel gears with tapered and uniform teeth, and forged straight bevel gear drives.; We have applied and computerized effective methods for determination of singularities of generated gear tooth surfaces, sufficient conditions of existence of an envelope to a family of surfaces represented in parametric form, and sufficient conditions of existence of envelopes to contact lines on the generated and generating surfaces.; A modified geometry of face-milled spiral bevel gears with tapered teeth that provides a localized bearing contact, reduces the level of noise and increases the strength of the teeth has been developed. The optimization of the geometry is based on local synthesis of the gear tooth surfaces that provides: (1) a localized bearing contact in the longitudinal or across the surface directions, (2) a reduced level of transmission errors of a parabolic type, and (3) the desired magnitude of the major axis of the instantaneous contact ellipse. The proposed method is tested by the investigation of the influence of misalignment by the tooth contact analysis (TCA) computer program, finite element analysis, and possible interference of the working and fillet surfaces of mating gears.; The meshing and contact of face-milled spiral bevel gears with uniform tooth height is considered as a special case of tapered tooth one. The same approach is applied for the design of low-noise and localized bearing contact of such gears.; A new type of geometry of straight bevel gears produced by forging has been proposed (together with F. L. Litvin) and developed. Similarly to the design of spiral bevel gears mentioned above, the generation of forged straight bevel gear is based on application of two imaginary head cutters of large radii with zero spiral angles and mismatched surfaces. The proposed geometry of forged straight bevel gear has the advantage of low level of transmission errors and stable bearing contact.