一种腰部为椭圆线的罗茨真空泵转子型线设计与分析

Design and Analysis of a Rotor Profile for Roots Vacuum Pumps with an Elliptical Waist

转子作为罗茨泵的关键零部件之一,对产品的整机性能具有重要影响,而转子设计的核心是转子型线的设计。本文以腰部椭圆线为基础开展转子型线设计,转子位于节圆内的型线由椭圆线构成,位于节圆外的型线由椭圆线的共轭曲线组成。设计中首先确定位于腰部的椭圆线及其啮合角,然后应用两个转子间的啮合关系,分析求解型线位于节圆外的共轭曲线,从而获得整个转子型线。最后,设计了抽速为70 L/s的罗茨泵转子,并分析了转子容积利用率与独立可变参数的关系。该型线与顶部为椭圆线的转子型线相比,容积利用率可大于50%,优势明显。

As a core component of Roots vacuum pump,the rotor has an important influence on the performance,and the design of rotor profile is critical to design rotor.In this study,the rotor profile is designed with the waist as the elliptical line,and its profile inside the pitch circle is composed of elliptical lines,while the profile outside the pitch circle is composed of the conjugate curves of elliptical lines.Firstly,the elliptical line located at the waist and its meshing angle are determined.Then,based on the meshing relationship between the two rotors,the conjugate curve of the profile line located outside the pitch circle is solved to obtain total rotor profile.Finally,the rotor of the Roots vacuum pump with a pumping speed of 70 L/s is designed,and the relationship of rotor volume utilization with independent variable parameters is analyzed.This profile has a significant advantage in the volume utilization rate that can be greater than 50%,compared to the rotor profile with the elliptical line at the top.