Scroll compressor orbital scroll drive and anti-rotation assembly

A scroll type compressor 10 having a housing 12, a non-orbital scroll 24, an orbital scroll 22, an orbital scroll drive 50, an anti-rotation assembly 54, and an axial thrust load assembly. The non-orbital scroll 24 is mounted in a rear casing of the housing 12. The orbital scroll 22 cooperates with the non-orbital scroll to form fluid pockets 46 and 48. The orbital scroll 22 is driven by an orbital drive 50 to move the fluid pockets to the center of the scrolls and compress the fluid sealed in the pockets. The anti-rotation assembly 54 includes cups 94 and pins 96 which define a circular orbit that is followed by bearings 104 on pins 100. The scroll drive 50 includes a drawn steel cup 70 that is driven by a drive shaft 82. A first bore 72, with an axis offset from the axis of the drive shaft 82, receives a knuckle bushing 62 which is rotatably attached to the orbital scroll 22. A balance weight 88 is journaled on the orbital scroll 22 and is driven by pin 86. The sliding connection between the cup 70 and the knuckle bushing permits some change in the orbit radius Ro of the orbital scroll 22. The cups 94 are sized relative to the bearings 104 to accommodate changes in the orbit radius Ro of the orbital scroll 22.