Design Method of Application Protocol of the Machine Parts Based on STEP

According to the requirement of extending application protocol, a geometric model description methods of the cone gear for final driver of automobile driving axle system based on STEP were presented(ZCAP203,ZCAP42). Application protocol AP214, ZCAP203 and ZCAP42 were carried out operation each other, and its application protocol(ZCAP) was constituted. New methodes are provided for the constitution of application protocol of all kind of the machine parts.