罗茨转子轮廓的双对称图解构造法

为实现罗茨转子便捷高效的轮廓构造,提出了一种双对称图解法。首先由转子副轮廓间的共轭关系,得出同一转子各轮廓分段间关于中轴和节圆切线的双对称构造关系;其次由给定的共轭段依序图解出待定共轭段和外过渡段及内过渡段;最后就抛物线例展开详细阐述。结果表明:双对称图解法的图解质量好,拟合精度高,更易于一般工程技术人员所理解;全轮廓段参与的共轭泄漏和径向泄漏更少。成果为同类转子便捷高效的轮廓构造提供了方法依据。

A Graphic Method with Bi-symmetry Axes Used for Profile Structure of Roots Rotor

In order to draw profile of roots rotor conveniently and efficiently, a bi-symmetric graphic method is proposed. Firstly, from the conjugate relationship between roots rotor profiles, a new profile structure relationship of single roots rotor with bi-symmetry axes of middle axis and instantaneous tangent line of pitch circle are derived. Secondly, according to the bi-symmetry relationship, the undetermined conjugate segment and outer transition segment and then inner transition profile segment are mapped out successively by given conjugate segment. Finally, a known outer parabola conjugate segment as example is implemented in detail. All results show that graphic quality of the bi-symmetric graphic method is good and its fitting accuracy is high, which is easier for ordinary engineers to understand; the full-profile conjugate mode contributes less conjugate leakage and radial leakage. The results provide a method basis for convenient and efficient profile construction of similar roots rotors.