Bending strength simulation of asymmetric involute tooth gears

抄録

Aiming at high load capacity, the design of the tooth profile which is not caught by the conventional profile is performed. Root stresses are calculated by 2D-FEM for various profile gears: 1) completely bilateral symmetry, 2) symmetry pressure angle and asymmetry fillet curve, and 3) asymmetry tooth. Reduction of root stress is brought by adoption of a higher pressure angle, and larger curvature radius of the fillet. Root stress of 40degrees of pressure angle tooth due to the unit tip load is reduced of 30% rather than ISO standard tooth. Nevertheless, the torque capacity for bending strength of higher pressure angle gears will not increase because of small base radius and low contact ratio. Tooth profile which has 25degrees of pressure angle with larger tooth root radius expect to perform higher torque capacity. The fatigue strength simulation method is also applied to those gears. The strength of tooth is estimated by comparing the local stress and the local strength restricted by defect size. Since the dangerous volume which takes higher stress becomes narrow, the profile with small width of tooth space expects that strength will enhance. According to the simulation, higher load capacities are expected in high pressure angle teeth than FEM calculation.