Internally-toothed gear unit with composite roller bearing, and wave gear device

A wave gear device characterized in comprising:

• an annular rigid internally-toothed gear;
• a flexible externally-toothed gear disposed coaxially on an inside of the rigid internally-toothed gear;
• a wave generator for causing the flexible externally-toothed gear to flex in a non-circular manner to partially mesh external teeth of the flexible externally-toothed gear with internal teeth of the rigid internally-toothed gear in the circumferential direction, and creating relative rotation between the gears by moving meshing positions of the gears in the circumferential direction;
• and
• a composite roller bearing for supporting the rigid internally-toothed gear and the flexible externally-toothed gear in a state that allows the two gears to rotate relative to each other;
• wherein
• the rigid internally-toothed gear has a first end surface and second end surface facing each other from a direction of a rotational center axis of the gear and extending in a direction perpendicular to the rotational center axis, and a circular external peripheral surface and circular internal peripheral surface positioned between the first end surface and the second end surface, internal teeth being formed in the circular internal peripheral surface;
• the composite roller bearing has an inner ring portion formed integrally with the internally-toothed gear, an outer ring, a plurality of first rolling objects, a plurality of second rolling objects, and a plurality of third rolling objects, with the first, second and third rolling objects being inserted in a rollable state between the inner ring portion and the outer ring;
• the inner ring portion has a first inner ring race surface formed in the first end surface of the internally-toothed gear, a second inner ring race surface formed in the second end surface of the internally-toothed gear, and a third inner ring race surface formed in the circular external peripheral surface of the internally-toothed gear;
• the outer ring has a first outer ring race surface facing the first inner ring race surface, a second outer ring race surface facing the second inner ring race surface, and a third outer ring race surface facing the third inner ring race surface;
• the first rolling objects for a thrust bearing are inserted between the first inner ring race surface and the first outer ring race surface;
• the second rolling objects for a thrust bearing are inserted between the second inner ring race surface and the second outer ring race surface;
• and
• the third rolling objects for a radial bearing are inserted between the third inner ring race surface and the third outer ring race surface.