高性能齿轮泵的一种双压力角齿廓构造方法

Tooth Profile Construction Method with Double Pressure Angles for High Performance Gear Pumps

为实现齿轮泵的高综合性能,提出了一种工作侧压力角大于非工作压力角的齿廓构造方法。通过对无根切无变位齿廓参数的分析,建立了泵轻量化、流量脉动和困油等性能系数关于工作压力角的解析式;依据齿顶圆弧角的最小许用值,给出了非工作压力角确定的一维迭代方法。结果表明,双压力角无变位的齿廓构造,既消除了根切现象,又可采用标准的加工方法;工作压力角越大,轻量化、困油和齿根抗弯等性能越好,流量脉动质量却越差;工作压力角越大,齿形曲率半径越大,齿面滑动系数和接触应力越小,轮齿磨损越小和寿命越长;齿顶高系数越大,流量脉动质量越好,困油性能越差,且对轻量化性能几乎无影响;由工作压力角和齿顶圆弧角许用下限共同确定非工作压力角,方法简单可靠等。得出无根切无变位双压力角齿轮能够实现泵的高综合性能的结论。

In order to achieve high comprehensive performance for external gear pumps,a tooth profile construction method with working pressure angles greater than non-working pressure angles is invented.From parameters analysis of tooth profiles without undercut and displacement,the analytical expressions of pump performance coefficients such as lightweight,flow ripple and trapped-oil phenomenon on working pressure angles are derived;then from the minimum allowable value of the addendumarc angle,a one-dimensional iterative model for determining non-working pressure angle is derived.All results show that the double pressure angles construction method not only eliminates the undercut phenomenon,but also adopts the standard machining;the greater the working pressure angle is,the better the performance of lightweight,oil trapping and tooth root bending resistance will be,but the worse the quality of the flow pulsation will become;the larger the working pressure angle is,the larger the radius of curvature of the tooth profile is,the smaller the sliding coefficient and contact stress of the tooth surface are,the smaller the wear of the gear teeth will be and the longer the service life will become;the higher the addendum height coefficient is,the better the flow pulsation quality is,the worse the oil trapping performance is,and there will be little impact on the lightweight performance.The non-working pressure angle is determined by the working pressure angle and the allowable lower limit of the addendum arc angle and this method is simple and reliable.It is concluded that the tooth profile construction method with working pressure angle greater than non-working pressure angle can achieve high comprehensive performance for external gear pumps.