The vacuum pump usually used traditional curves such as the circular, cycloidal curves and their combinations to construct tooth profile. However, to increase efficiency and design flexibility for the vacuum pump, a novel rotor tooth profile for Roots rotor of vacuum pumps is proposed. Which is named “CEIEC” tooth profile and orderly composed of five significant segments, a circular arc for tooth tip, an epicycloid curve with variable extension, an involute, an enveloped epicycloid curve and a conjugated circular arc for tooth root. A numerical example is presented to evaluate the performance indices for proposed vacuum pump, including the hermeticity coefficients of the rotor mesh gap and tip gap.

中文翻译：

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转子齿形设计参数对真空泵性能影响的研究

真空泵通常使用圆形、摆线及其组合等传统曲线来构造齿形。然而，为了提高真空泵的效率和设计灵活性，提出了一种用于真空泵罗茨转子的新型转子齿形。它被命名为“CEIEC”齿形，由五个重要的段依次组成：齿尖圆弧、变伸外摆线曲线、渐开线、包络外摆线曲线和齿根共轭圆弧。给出了一个数值例子来评估所提出的真空泵的性能指标，包括转子啮合间隙和尖端间隙的密封系数。