抄録
In order to support the product design process in manufacturing industry, a method of deriving the idea for solving functional tradeoffs is developed. After specifying the most important tradeoffs to solve, physical causal relationship model is drawn to extract the cause of functional tradeoffs, and then the physical causal relationship model is applied to the contradiction matrix in TRIZ based on physical dimension. Based on the inventive principles indicated by the contradiction matrix, priority ranking of the inventive principles is conducted, thus giving a useful hint of what kind of idea can be thought of to solve tradeoff problems. At the end, a case study of solving the tradeoff problems for CVT （Continuously Variable Transmission） in motor vehicle is conducted to prove the effectiveness of the proposed method.
