Reliability-Based Optimum Tolerance Design for Industrial Electromagnetic Devices

Principle of tolerance design is receiving increased research focus to determine the optimal tradeoff between manufacturing cost and quality. However, current tolerance designs are not suitable for products such as electromagnetic devices that require high reliability, i.e., a very low failure rate. In this paper, a new tolerance design named as reliability-based optimum tolerance design is formulated and performed to guarantee the high reliability of the products while maximizing manufacturing tolerances. The proposed method quantifies the reliability using reliability analysis, which reflects the tolerance in the tolerance design. To validate the proposed method, tolerance design is applied to two examples: 1) a magnetic circuit ( C -core) and 2) a mass-produced interior permanent magnet motor that contains manufacturing tolerances of permanent magnet.