Gear Pairs
The Gear Pair node connects two spur gears, helical gears, or bevel gears in such a way that, at the contact point, they have no relative motion along the line of action. The remaining displacements and rotations of both the gears are independent of each other.
In the case of a line contact model, one additional constraint is added to restrict the relative rotation about a line joining the two gear centers. When friction is included for a gear pair, frictional forces in the plane perpendicular to the line of action are added on both of the gears.
The Gear Pair node is a global feature and takes two gears as input, thus providing the connection between the selected gears.
In the Rotordynamics Module, the rotor does not physically rotate. However, the mesh stiffness, which is periodic within a mesh cycle or within a full revolution of the gear, should account for the physical rotation of the gear. Therefore, the magnitude of the rotation of the gears is obtained by time integrating the respective angular velocities. This rotation is then added in the rotation that is due to torsional deformation of the shafts to specify the periodicity of the gear mesh stiffness.
For details about the theory of gear pairs, see Gear Pair Theory.