短语词组短语Piston and rod assembly 向导轴承piston top rod 动力活塞顶杆piston connecting rod unit 活塞连杆组piston push rod 活塞推杆piston and rod group 活塞与连杆组件piston tail rod 活塞尾杆double piston -rod 双活塞杆piston n rod 活塞连杆;活塞杆 返回 piston rod