The geometry of a worm is similar to that of a powerscrew.
蜗杆的几何形状类似于机械螺纹，蜗杆的转动与一个渐开线导轨直线移动是相仿的。
2
Deals with screws and fasteners including powerscrew and preload fasteners.
讨论螺钉、螺杆等紧固件的设计，包括传动螺杆和预加载紧固件。
3
But because it now oil and chemical use screw compressor for flow and pressure from the shaft power, high demands, at present basically also rely on imports.