Patent ID: 8875598

Claim:
A unit type wave gear device ( 1 ) characterized in comprising: a tubular unit housing ( 2 ); a wave gear mechanism ( 3 ) coaxially disposed inside the unit housing ( 2 ); and an input shaft ( 4 ) passing through a center of the wave gear mechanism ( 3 ) and extending coaxially with the wave gear mechanism ( 3 ); wherein the unit housing ( 2 ) has a cylindrical member ( 5 ), an end plate ( 6 ) fixed to a first end face ( 5 a ) formed at one end of the cylindrical member ( 5 ) along an axial line ( 1 a ) of the cylindrical member, and a two-stage cross roller bearing ( 7 ) disposed on a side of a second end face ( 5 b ) formed at the other end of the cylindrical member ( 5 ) along the axial line ( 1 a ); the two-stage cross roller bearing ( 7 ) has an outer ring ( 11 ) fixed to the second end face ( 5 b ) of the cylindrical member ( 5 ), an intermediate ring ( 12 ) concentrically disposed on an inner side of the outer ring ( 11 ), an inner ring ( 13 ) concentrically disposed on an inner side of the intermediate ring ( 12 ), an outer track ( 14 ) of rectangular cross-section formed between the outer ring ( 11 ) and the intermediate ring ( 12 ), a plurality of outer rollers ( 15 ) rollably inserted into the outer track ( 14 ), an inner track ( 16 ) of rectangular cross-section formed between the intermediate ring ( 12 ) and the inner ring ( 13 ), and a plurality of inner rollers ( 17 ) inserted in a rollable state into the inner track ( 16 ); the wave gear mechanism ( 3 ) has an annular rigid internally toothed gear ( 21 ), a flexible externally toothed gear ( 22 ) coaxially disposed on an inner side of the rigid internally toothed gear ( 21 ), and a wave generator ( 23 ) coaxially disposed on an inner side of the flexible externally toothed gear ( 22 ), wherein the flexible externally toothed gear ( 22 ) has a flexible barrel part ( 22 a ) having a cylindrical shape, a diaphragm ( 22 b ) widening outward in a radial direction from an end of the barrel part ( 22 a ) at a side of the two-stage cross roller bearing ( 7 ), a rigid boss ( 22 c ) having an annular shape and integrally formed in an outer circumferential edge of the diaphragm ( 22 b ), and external teeth ( 22 d ) formed in an outer circumferential face portion of the end of the barrel part ( 22 a ) at a side of the end plate ( 6 ), and wherein the rigid internally toothed gear ( 21 ) is fixed to the cylindrical member ( 5 ), the boss ( 22 c ) is fixed to the intermediate ring ( 12 ), and the wave generator ( 23 ) is fixed to the input shaft ( 4 ) extending through a center of the wave generator ( 23 ); and a shaft end part ( 4 a ) of the input shaft ( 4 ) on the side of the two-stage cross roller bearing ( 7 ) is fixed to the inner ring ( 13 ).