Lubricant supplying mechanism for a wave gear drive

A wave gear drive, comprising:

• a circular rigid internal gear formed with a circumferential inner surface thereof with internal teeth,
• a circular flexible external gear located inside the rigid internal gear and formed with a circumferential outer surface thereof with external teeth which are engageable with the internal teeth,
• a wave generator having a wave bearing fixed on a circumferential inner surface of the flexible external gear,
• resilient seal ring means provided to seal substantially between inside and outside portions of the flexible external gear for preventing lubricant from circulating therebetween,
• a first end plate,
• a second end plate, and
• bearing means,
• the flexible external gear being of a silk hat shape and having a cylindrical body, a circular diaphragm extending radially and outward from one end of the body, a circular boss formed integrally on an outer peripheral edge of the diaphragm, and external teeth formed on a circumferential outer surface of the body at a side of an open end thereof,
• the boss of the flexible external gear, the bearing means, and the rigid internal gear being arranged between the first and second end plates so as to define a substantially sealed inside space of the wave gear drive, and
• the resilient seal ring means being engaged between the open end of the flexible external gear and the second end plate which faces the open end so that the inside space of the wave gear drive is divided into the inside and outside portions of the flexible external gear;
• wherein the resilient seal ring means has a first end portion which is mounted on the open end of the body of the external flexible gear and a second end portion which abuts resiliently against an inner-side surface of the second end plate.