Tolerance based Gear Design
The design and optimization of gears is an important part of the extensive field of activity since the beginning of the gear department at the WZL. Therefore, we are able to use our previous knowledge together with a huge data base, for new gear designs or adjusting existing designs. Based on standards and the FE-based tooth contact analysis, the macro and micro geometry of gears design is specifically tailored to given requirements.
The design process of transmissions is highly complex. Because of competing design objectives (durability, noise excitation, efficiency, cost), the engineer needs to find the optimal balance of design objectives for each gear design. The macro and micro geometry should satisfy all the requirements of the transmission. The macro geometry needs to comply to for example the design space or the maximum torque level. While designing the micro geometry manufacturing and assembly tolerance together with load induced displacements need to be considered.
The objective of the gear design process needs to be the optimal macro and micro geometry design taking restrictions, manufacturing and assembly tolerances into account. The optimal gear design satisfies all customer requirements and presents the best tradeoff between quality and stability within the considered tolerance fields.
The design method for gears is based on validated calculation approaches and was used successfully in past research and industry projects of the WZL gear department. The calculation approaches consist of the FE-based tooth contact analysis developed at the WZL and standards. Because of the modular structure of the method, it is possible to satisfy various customer specific requirements of the gear design. First, an optimal macro geometry under the given restrictions, such as design space, is to be determined. The macro geometry needs to satisfy the durability, noise excitation, efficiency and cost requirements. Once an optimal macro geometry is determined, the micro geometry of the gear is to be optimized. Based on the FE-based tooth contact analysis, a sensitivity analysis concerning the tolerance fields of the gear is conducted. The various micro geometries can be graded regarding its operational behavior. Next, the influence of manufacturing and assembly tolerances upon the operational behavior are investigated for every micro geometry design. The optimal micro geometry in terms of quality and stability of the operational behavior within the tolerance fields is selected. Thus, specific tolerance fields can be determined which could lead to cost reduction within the manufacturing process.
Jens Brimmers, M.Sc. M.Sc. Workgroup Leader
Tel.: +49 241 80-27737
Fax: +49 241 80-22293