短語詞組短語piston fastening bolt 活塞緊固螺釘piston retaining bolt 柱塞固定螺栓piston rod bolt 活塞桿螺拴articulation cylinder piston retaining bolt 鉸接油缸活塞固定螺栓piston junk ring bolt 活塞壓環(huán)螺釘piston -rod spool bolt 活塞桿接頭螺栓 返回 piston bolt