Curvilinear circular-arc tooth gears for use in external gear pumps

Abstract

A curvilinear circular-arc-toothed (CCAT) gear for improving gear performance and reducing noise while avoiding axial loads common to helical gears includes an annular gear body; and a gear tooth having a hybrid gear tooth profile comprising one or more curves configured to provide a sweep of the gear tooth space by a mating gear tooth while maintaining smooth contact during gear mesh, and wherein the gear tooth extends along an axial length of the gear body along an axial profile.

What is claimed is: 
     
         1 . A curvilinear circular-arc-toothed (CCAT) gear for improving gear performance and reducing noise while avoiding axial loads common to helical gears, the CCAT gear comprising:
 an annular gear body; and   a set of gear teeth, with each tooth extending radially away from the gear body and extending axially along the gear body, and   wherein the gear tooth has a cross-sectional profile transverse to the rotational axis of the gear body, the cross-sectional profile formed from a hybridization of two or more curves, the two or more curves defining a tooth tip, a tooth flank, and a tooth root, and   wherein the gear tooth has an axial tooth profile defining a circumferential positioning of the gear tooth on the gear body relative to a respective axial positioning of the gear tooth on the gear body, the axial tooth profile being generally symmetric across the midplane of the gear to reduce axial loading on gears induced by gear meshing.   
     
     
         2 . The CCAT gear of  claim 1 , wherein the axial tooth profile is continuously differentiable. 
     
     
         3 . The CCAT gear of  claim 1 , wherein the axial tooth profile is fully symmetric about an axial mid-plane of the gear to eliminate axial loading from gear meshing. 
     
     
         4 . The CCAT gear of  claim 1 , wherein the axial tooth profile has an initial helix angle at each end of the gear. 
     
     
         5 . The CCAT gear of  claim 1 , wherein the axial tooth profile is curvilinear. 
     
     
         6 . The CCAT gear of  claim 5 , wherein the axial tooth profile is a half-period sinusoid function. 
     
     
         7 . The CCAT gear of  claim 1 , wherein the gear tooth cross-sectional profile is configured such that the tip fully sweeps along a tooth root of a mating gear. 
     
     
         8 . The CCAT gear of  claim 7 , wherein the tooth tip and root profiles include a circular-arc. 
     
     
         9 . The CCAT gear of  claim 1 , wherein the tooth flank is a curve that allows smooth meshing of the gears. 
     
     
         10 . The CCAT gear of  claim 9 , wherein the tooth flank is involute, cycloidal, or circular arc. 
     
     
         11 . The CCAT gear of  claim 9 , wherein the tooth flank is an involute curve. 
     
     
         12 . The CCAT gear of  claim 1 , wherein the tooth tip is circular, the tooth flank is involute, and the tooth root is circular. 
     
     
         13 . The CCAT gear of  claim 1 , wherein the two or more curves of the hybrid tooth profile are combined such that the cross-sectional profile of the tooth is continuously differentiable. 
     
     
         14 . The CCAT gear of  claim 1 , wherein the gear teeth extend radially outward from the annular body. 
     
     
         15 . A curvilinear circular-arc-toothed (CCAT) gear for improving gear performance and reducing noise while reducing axial loads common to helical gears, the CCAT gear comprising:
 an annular gear body; and   a gear tooth having a hybrid gear tooth profile comprising one or more curves configured to provide a sweep of the gear tooth space by a mating gear tooth while maintaining smooth contact during gear mesh, and wherein the gear tooth extends along an axial length of the gear body along an axial profile.   
     
     
         16 . The CCAT gear of  claim 15 , wherein the hybrid gear tooth profile has a tip that conforms to a tooth root of the mating gear to allow fully sweeping out the volume between gear teeth to improve efficiency and reduce noise. 
     
     
         17 . The CCAT gear of  claim 16 , wherein the hybrid gear tooth profile has a circular arc at a tooth tip, a circular arc at a tooth root, and the profile combines the two arcs with an involute curve between the circular arcs to allow a full sweep of the volume between gear teeth while maintaining a constant line of action of the mesh. 
     
     
         18 . The CCAT gear of  claim 15 , wherein a radius of a tooth tip arc is equal to or less than a radius of a tooth root arc. 
     
     
         19 . The CCAT gear of  claim 15 , wherein the hybrid profile is continuously differentiable. 
     
     
         20 . The CCAT gear of  claim 15 , wherein the axial profile is configured to cause gradual contact between teeth to reduce shock stress on the gear teeth and noise during meshing. 
     
     
         21 . The CCAT gear of  claim 15 , wherein the axial profile is configured to balance axial forces imparted on the gears from meshing to reduce net axial load on the gear.