( 2 ) taking the vehicle platform variant as precondition , this paper deeply researches the function - structure and function - structure decomposition of rear - axle . the rear - axle product model for variant design is built using general cad software ( unigraphics ) ( 2 )以满足平台改型设计需求为前提,深入研究了汽车后桥的功能结构和功能结构分解,利用通用cad软件( unigraphics )建立了适应变型设计的汽车后桥产品模型。