罗茨泵用高能渐开线新型转子的型线研究

Study on a New Involute Rotor Profile for Roots Pump with High-performance

为兼顾罗茨泵的高容积利用率、高容积效率、无闭气现象等性能的需要,提出一款具有密封用隆八字顶的渐开线转子型线。基于具有最大形状系数的渐开线转子型线,构建顶同心圆弧、减重八字弧、主渐开线、谷部避让圆弧组成的新型转子型线;给出主渐开线最简单的参数化方程;并就新型转子型线的最大形状系数等进行实例运算和分析。结果表明:2叶、3叶新型转子隆八字半角1°~6°间的最大形状系数分别增效3. 45%~7. 99%、4. 55%~10. 54%,叶数越多和隆半角越小,增效越突出;给出的新型转子形状系数线性拟合方程的误差,2叶的小于0. 02%,3叶的小于0. 4%,精度极高,均可直接采用;八字顶能有效控制径向泄漏,提高容积效率;八字顶和谷避让圆弧结构简单、易加工。研究结果为罗茨泵其他型线的增效设计,提供一种新方法。

For the need to increase effect of volume utilization rate and volume efficiency for roots pump,a new profile with splayed head for involute rotors was created. Firstly,based on the common profile of involute rotor with max shape coefficients,a new profile composed by top concentric arc,splayed arc for light weight,main involute,bottom avoidance arc was built to enhance shape coefficients and volume utilization rate. Secondly,the simplest parameter coordinate equations of main involute were derived,then the two shape coefficients were computed and results were analyzed as an example. All results indicate that along with the half angle of splayed head is from 1° to 6°,the shape coefficient increase rate of the new profile relative to common profile are respectively from 3. 45% to 7. 99% used in two teeth rotors,and from 4. 55% to 10. 54% in three teeth rotors;the more teeth number is and the smaller half angle of trapezoid head is,the more outstanding increase effect is;the relative fit error of the new shape coefficients is smaller than 0. 02% in two teeth rotors,and smaller than 0. 4% in three teeth rotors,fit accuracy is extremely high enough to be used directly;the radial leakage is effectively controlled and higher volume efficiency is provided by the splayed head;outstandingly,the simple structure of the splayed head and avoidance arc head are easy to proces,etc. It is concluded that a new enhancement design is provided for other profile innovation in roots pump.