Rotary vane machine with rings radially constraining the vanes

A fluid displacement machine having a pair of spaced apart end walls and a substantially cylindrical wall extending between them which walls together form a substantially cylindrical hollow chamber, a rotor mounted for rotation within said chamber about an axis eccentric relative to the latter and being contiguous with said substantially cylindrical chamber wall along a generatrix thereof, said rotor having a pair of spaced apart end pieces sealingly engaging said end walls of said hollow chamber, said rotor also having vanes which extend axially between said end pieces, and which project substantially radially and which are displaceable in a substantially radial direction, said vanes having circumferential edges adapted to directly contact said substantially cylindrical chamber wall and thereby define working spaces which, during rotation of said rotor, move around said chamber while varying in volume, said vanes each having a lug at a radially inward position at both axially opposite ends thereof and projecting axially from said axially opposite ends of said vanes, each of said lugs having an edge, facing radially outwardly and providing an abutment surface spaced inwardly from said circumferential edge of said vane, and constraining members displaceable relative to said rotor and operatively associated with said vanes of said rotor to limit outward radial displacement thereof, said members determining limit positions for the vanes in which said circumferential edges of said vanes make only a desired degree of contact with said substantially cylindrical chamber wall, thereby preventing excessive contact pressure between said chamber wall and said circumferential edges, said constraining members including first and second rings each surrounding the lugs at a respective said end of said vanes, with said abutment surfaces bearing against the internal surfaces of said rings, characterized in that said end pieces form a part of said rotor so as to rotate coaxially therewith and are cup shaped and each has a cavity in the confronting end faces thereof so that each of said first and second rings and said lugs surrounded thereby are received in said cavity in the adjacent said end pieces, each of said end pieces surrounding the adjacent said ring and said lug radially outwardly of and in sliding contact with said ring, and wherein said abutment surfaces each have an axially extending apex to allow said vanes to rock relative to said rings.