evolve的名词形式是什么

evolve的名词形式是evolvent，evolvent中文意思是n. 渐开线；渐伸线；切展线

The gear profile was designed with simple proximate drawing using proximate arcograph to instead of evolvent in the past.齿轮齿形设计多采用简易的近似划法-用近似圆弧代替渐开线。