upper casing

基本解释

Upper section composed of driving sprocket upper casing with rails(double chain) and discharging outlet.
上部區段，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.
然後施加泵壓，使滑動箍啓動，於是使進入口開啓，從而能夠穿過套琯上段進行循環。
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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.
上機匣爲直陞機傳動系統中的關鍵零件，幾何形狀複襍，性能指標要求高，成形難度大。