The wave generator is designed as holder 5 which contains two balls 4 and is driven by circular cylindrical friction wheel 1. Wheel 1 rotates about fixed axis A. Flexible (radially deflectable) ring gear 2, having teeth on its outside circumference, rotates about fixed axis B and meshes at two opposing areas with the teeth of circular internal gear 3 which is rigidly attached to the base, i.e. fixed. Balls 4 radially deflect ring gear 2 so that a large number of teeth are simultaneously in engagement in two areas located symmetrically with respect to axis a-a which is perpendicular to axis b-b passing through the centres 0 of balls 4. The transmission ratio from wave generator 5 to link 2 is i₅₂=ω₅/ω₂=n₅/n₂=-z₂/2 where ω₅, ω₂, n₅ and n₂ are the angular velocities and speeds (in rpm) of generator 5 and link 2; and z₂ is the number of teeth of link 2, which is equal to z₂=z₃-2.
$2927$CxG,SW$