Basic design principle of low noise gear pump

The transient flow rate of the gear pump depends on the position of the meshing point. When the gear meshes, the meshing point always moves on the meshing line. From this point of view, the pressure pulsation of the gear pump caused by the flow change is unavoidable. Through systematic meshing analysis, it was found that the special meshing process of the straight-line conjugate internal gear pair was utilized. The major feature of this meshing is the relationship between the meshing line and the coincidence coefficient and the tooth tip height.
The downward bending at the top of the tooth is very different from the common involute internal gear. Therefore, in FIG. 2 , the coincidence coefficient sharply increases near the top of the tooth, which means that the meshing time of the tooth profile near the top of the tooth is longer than the tooth profile of the other parts, and the effect of increasing the degree of coincidence is much greater. In the involute gear pump, the meshing line is a straight line, and the radial motion of the meshing point during operation inevitably causes pressure pulsation; while the straight conjugated internal meshing gear mainly meshes near the tooth tip, and the radial displacement of the meshing point is small. This is where the pressure pulsation is small! Therefore, as long as the radial displacement of the meshing point in the meshing process is reduced, the output pressure pulsation and running noise can be effectively reduced. This should be the basic design principle of the low noise gear pump .