罗茨真空泵偏心大圆弧转子型线设计及分析

Design and Analysis of Eccentric Large Arc Rotor Profile of Roots Vacuum Pump

转子型线的设计是罗茨泵研究的重要内容之一。偏心大圆弧转子型线由圆心位于节圆内横坐标负半轴的圆弧、销齿圆弧及其共轭曲线组成。首先确定转子偏心大圆弧、顶部销齿圆弧以及偏心大圆弧对应的共轭曲线,完成了理论型线的设计;然后根据理论型线和实际型线的转换关系,获得实际型线的设计方法;最后在给定的罗茨泵抽速、转子中心距和间隙下,完成了转子的型线设计。研究发现,当节圆半径和顶圆半径相同时,偏心大圆弧转子型线的容积利用系数高于圆弧转子型线的容积利用系数。研究为偏心大圆弧转子罗茨泵的制造奠定了基础。

Roots pump rotor profile design is the important contents of Roots pump research.The profile of the eccentric large arc rotor is composed of the arc whose center is located on the negative semi-axis of abscissa in the pitch circle,the pin tooth arc and its conjugate curve.First,the design parameters and range of the eccentric large arc,and the pin tooth arc on the top of the rotor are determined,and the conjugate curve is obtained corresponding to the eccentric large arc from the meshing characteristics.Then,according to the conversion relationship between the theoretical profile and the actual profile of the rotor,the design method of the actual profile is analyzed.Finally,according to the pumping speed,rotors center distance and rotors gap of the Roots pump,the theoretical and actual profiles of the rotor are designed.The study found that the volume utilization rate of the eccentric large arc rotor profile is higher than that of the circular arc rotor profile when the pitch radius and tip circle radius are the same.