Patent ID: 8770064

Claim:
A wave generator for a wave gear device wherein a flexible externally toothed gear disposed inside an annular rigid internally toothed gear is bent into a non-circular shape and caused to partially mesh with the rigid internally toothed gear to move the meshing positions of the two toothed gears in a circumferential direction and to generate relative rotation between the toothed gears brought about by a difference in the number of teeth of the two toothed gears, comprising: a rigid plug; and an annular flexible bearing bent into a non-circular shape by a non-circular external circumferential surface of the rigid plug; wherein the flexible bearing is a deep-groove ball bearing having an annular flexible outer race and flexible inner race capable of bending in a radial direction; wherein pitch circle diameters PCD of the flexible externally toothed gear of each model of the wave gear device are set as shown in Table below, and the ball diameters Da of the flexible bearing are set as shown in the Table according to each model of the wave gear device; and wherein dimensions of orbital plane radii ro, ri of the inner and outer races are set so that the ratio ro/Da of the orbital plane radius ro of the inner race and the ball diameter Da, as well as the ratio ri/Da of the orbital plane radius ri of the outer race and the ball diameter Da, are both in the range of 0.51 to 0.52 in each model of the wave gear device as shown in the Table: TABLE PCD (mm) of Flexible Ball Model Externally Diameter No. Toothed Gear Da (mm) ro/Da ri/Da 8 20.320 2.1-2.3 0.51-0.52 0.51-0.52 11 28.22 2.5-2.7 14 34.925 3.3-3.7 17 43.180 4.2-4.6 20 50.800 5.0-5.5 25 63.500 5.8-6.4 32 82.550 7.5-8.2 40 101.600 10.0-10.9 45 114.300 11.5-12.6 50 127.00 12.5-13.7 58 147.320 14.2-15.5 65 165.100 15.0-16.4 80 203.200 20.0-21.9 90 228.600 22.5-24.6 100 254.00 25.0-27.4.