论文部分内容阅读
飞机上冷热系统汽路开关的种类很多,过去这些开关多采用平板活门,体积大,结构较复杂,工艺性不好。近年来逐渐改用结构简单、体积小的锥形活门开关。 锥形活门开关的特点:与活门配合的密封带以线接触为最理想,但从使用寿命角度考虑,应加宽密封带;可是密封带越宽则密封性越差;故要求有一个窄小的密封带,其圆度、圆柱度不大于0.01毫米,表面粗糙度不大于Ra0.4微米。这给加工带来困难,也使成本随之提高。 我厂在QDF产品上使用的锥形活门见图
Hot and cold systems on the aircraft many kinds of steam circuit switches in the past these switches to use more flat-panel valve, bulky, complex structure, technology is not good. In recent years, gradually switch to the structure is simple, small cone valve. Conical valve switch features: with the valve with the sealing line to the best contact with the line, but from the service life point of view, should be widened sealing tape; However, the wider the seal with the worse the sealing; it requires a narrow Of the sealing tape, the roundness, cylindricality of not more than 0.01 mm, the surface roughness of not more than Ra0.4 microns. This brings difficulties to processing and increases costs. My factory uses the conical valve on the QDF product