Crossed roller bearing

A crossed roller bearing comprising:

• an inner ring and an outer ring;
• a roller raceway that is formed between an inner ring-side V-groove formed in an inner-ring outer circumferential surface and an outer ring-side V-groove formed in an outer-ring inner circumferential surface;
• a plurality of rollers inserted into the roller raceway;
• a roller insertion groove formed in the inner ring for inserting the rollers into the roller raceway;
• and
• a plug for sealing the roller insertion groove,
• wherein the inner ring-side V-groove has:
• a pair of inclined raceway surfaces along which the roller roll;
• a concave surface formed between the inclined raceway surfaces so as to not contact with the rollers;
• and
• a minimum outer diameter section of the inner ring, the minimum outer diameter section being located within the concave surface,
• wherein the roller insertion groove has:
• an end face-side groove opening that exposes to one of ring-shaped end faces of the inner ring;
• and
• an outer circumferential surface-side groove opening that continues to the end face-side groove opening and exposes to the inner ring-side V-groove in the inner-ring outer circumferential surface, and
• wherein the outer circumferential surface-side groove opening is defined by a circumferential direction opening edge extending in a circumferential direction along the inner ring-side V-groove and a pair of side opening edges extending from both ends of the circumferential direction opening edge to the ring-shaped end faces, and
• the circumferential direction opening edge of the roller insertion groove is formed at a position deviated from the minimum diameter section of the concave surface.