Jixie chuandong (Apr 2023)
Tooth Profile Construction Method with Double Pressure Angles for High Performance Gear Pumps
Abstract
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.
