| 摘要 |
PURPOSE:To prevent the occurrence of cavitation due to increase in the inflow speed of fluid and pressure drop at the beginning of intake action by curvilinearly correcting the unengaged part of an internal gear to secure the minimum gap area between gears more than its set value. CONSTITUTION:When the minimum gap area between an internal gear 1 and an external one 2 is denoted by Somm<2>, tooth width by Hmm. the number of revolutions being in use by nr.p.m, a gas area between the external gear 2 and the internal gear 1 at the position where the gear 2 rotates by angle thetaby S, and the occurring speed of natural cavitation of fluid being in use by Vomm/sec respectively, the curve of the unengaged domain of the internal gear 1 is corrected so as to satisfy the equation of So>=6XHXnXds/ dtheta/(2XVo)-S. This curvilinear correction secures the minimum gap area So more than its set value to prevent the occurrence of cavitation due to increase in the inflow speed of fluid and pressure drop at the beginning of intake action. Thus pump efficiency can be improved in its high rotating range, and a pump life can be also lengthened. |
