Robot joint with an electric drive motor

A robot joint comprising a support part formed with a first bore;

• a robot part supported for rotation on said support part and being formed with a recess which communicates with said first bore;
• an electric motor mounted on said support part and being connected to a drive shaft which extends through said bore into said recess and is rotatable about a center axis;
• harmonic-drive-type reduction gears including an elliptical driving disk secured to said drive shaft, an elliptical ball bearing mounted on said driving disk and engaging without play the inner side of an elastically deformable, externally toothed ring;
• an elastically deformable, sleeve-shaped intermediate transmission member secured at one end thereof to said externally toothed ring and extending around said center axis into said recess and an internally toothed ring secured to said robot part and engaging at two diametrically opposed locations said externally toothed ring, said internally toothed ring having a different number of teeth than said externally toothed ring;
• a first annular mounting face provided on said support part around said first bore and being formed with radial teeth, a rigid flange secured to the opposite end of said intermediate transmission member, said rigid flange having a second annular mounting face provided with radial teeth engaging the radial teeth on the first mounting face;
• and means for fastening said rigid flange to said first mounting face.