短语词组短语butt -muff coupling 刚性联轴器;对接套筒联结器butt components coupling 元件耦合butt muff coupling 筒形联轴器;刚性联轴器cased butt coupling 套筒式联轴器case butt coupling 套筒式联轴器end -butt coupling 端接耦合;端环 返回 butt coupling