Patent ID: 8092333

Claim:
A traction drive transmission device, comprising: rolling bodies arranged between an input shaft and an output shaft, the traction of said rolling bodies changing the number of revolutions of said input shaft into a desired transmission ratio and output from said output shaft, and said input shaft and output shaft connected in left/right symmetry to perform two stage transmissions, wherein a first rolling body retaining portion extending between adjacent rolling bodies is provided on a first retainer provided with said input shaft, a second rolling body retaining portion extending between adjacent rolling bodies is provided on a second retainer provided with said output shaft, the input shaft, the first retainer and the first rolling body retaining portion are formed as a single part, the output shaft, the second retainer and the second rolling body retaining portion are formed as a single part, a rotation axis of said rolling bodies is arranged at an incline so that the rotation axis is not orthogonal to the axis of said input shaft and said output shaft, and said traction drive transmission device further comprises: a preload adjusting part for automatically changing a preload applied to said rolling bodies corresponding to a torque between shafts which connect a first stage transmission section and a second stage transmission section; and a transmission ratio variation mechanism connected to a traction input-output member of said rolling bodies, for changing said transmission ratio by performing number of revolutions control of said traction input-output member, wherein said preload adjusting part is one where, in a torque transmission structure which performs torque transmission between opposing faces of two members which are arranged so as to rotate on the same axes, recesses which form an incline face or curved face in cross-section are provided in a plurality of sets between said opposing faces, and a load regulation cam having a cylindrical shape is disposed in a space of said recesses.