upper casing

基本解釋

Upper section composed of driving sprocket upper casing with rails(double chain) and discharging outlet.
上部區(qū)段，由傳動鏈輪及帶有軌道（雙排鏈）的上部機殼、卸料口組成。
Applying pump pressure then activates a sliding collar that opens access ports, enabling circulation across the upper casing interval.
然后施加泵壓，使滑動箍啟動，于是使進入口開啟，從而能夠穿過套管上段進行循環(huán)。
www.infopetro.com.cn
Upper casing, as a key part in the driving system of helicopter, is difficult to be formed owing to its complex geometry and high demand for property.
上機匣為直升機傳動系統(tǒng)中的關鍵零件，幾何形狀復雜，性能指標要求高，成形難度大。