Patent ID: 7470064

Claim:
An axial thrust bearing for axially supporting a rotating shaft of an exhaust gas turbocharger connected to a lubricating oil circuit, the bearing comprising a profiled annular bearing surface which contacts an essentially flat sliding surface, the bearing surface comprising: an inside circumference and an outside circumference which bound the bearing surface radially; a plurality of grooves extending radially from the inside circumference to the outside circumference, said grooves being open on the outside circumference; a plurality of coplanar flat trap surfaces located between respective pairs of adjacent said grooves such that only one of said flat trap surfaces is arranged between each of the respective pairs of adjacent grooves; and a plurality of wedge surfaces located between adjacent pairs of respective said grooves such that only one of said wedge surfaces is arranged between each of the respective pairs of adjacent grooves, each said wedge surface forming a lubricating oil gap which narrows circumferentially toward an adjacent said flat trap surface and which narrows radially toward said outside circumference such that a shear rate includes circumferential component and a radial component.