三螺杆泵螺旋齿形中心角的影响

Influence of the gear center angle of three-screw pump

论述了三螺杆泵螺旋齿形中心角α的大小与泵的流量无关.并论证了α角直接影响到介质作用在螺旋上的扭矩.只有当介质作用在从动螺杆上的扭矩为负值时,从动螺杆才能在介质压力引起的扭矩作用下产生自转扭矩.文章论证了我国广泛采用的、基于А.Е.Жмудь提出的α=0.18π是理想齿形的理论是错误的,推导了三螺杆泵若要处于理想的运转状态,即从动螺杆的旋转不是由主动螺杆带动,而是由介质压力推动,只起"密封器"的作用,α必须小于0.166027π.同时说明我国少数制造厂采用的"四等分"齿形,也是不合理的齿形.这些不理想的齿形会导致降低泵的机械效率和寿命.

The size of screw center angle a of three screw pump has nothing to do with flux of the pump, and then α angle is demonstrated to relate directly to the wring moment by medium on the screw surface. Only the wring moment is minus, the self-rotating wring moment on the driven screw medium will be created by the medium. The paper also demonstrates that the conclusion that α is equal to 0. 18 π presented by A.E.ЖMyДb that is widely adopted in our country is false, and deduces that three-screw pump has the perfect running state if α angle is less than 0.166027π. The perfect running state means that the rotation of the driven screw is not driven by the active screw, but by the medium, and the function of the driven screw is only as the sealer. Finally, the paper explains that the quartering screw shape made by few manufacturers is not per.fect, and the unper.fected screw shape results in the fall of the mechanical efficiency and life.