Kinematic and force analysis of a composite gear system with separation of sliding and rolling between meshing profiles

The paper describes a comprehensive study of a novel gear design with physical separation between sliding and rolling motions in the contact point of meshing gears. The sliding motion is accommodated by shear deformation of a thin-layered rubber-metal laminate allowing very high compression loads. Kinematic conditions of such “composite” gear system were studied analytically. Closed form solutions were obtained for two different shapes of the composite tooth core, and were optimized for a gear pair used in the final stage of a helicopter rotor transmission. Static and dynamic stress analyses were also performed, using the finite element approach for complex meshing conditions involving interaction of metal and elastomeric (rubber) materials. The results obtained for the composite gear system compare beneficially to the conventional involute gears. A working prototype was built and tested for the analyzed model, and has shown a good correlation of the strain data as well as kinematics.