Disc brake cooling structure

Claim 1

A brake disc for a railway vehicle disc brake operable in both directions of rotation and comprising a friction ring mounted on the end of a wheel hub to define an open space radially inwardly of said friction ring, a plurality of radial ribs attached to said friction ring to define cooling air ducts, a radial impeller disposed radially inwardly of said friction ring within the peripheral edge portion of said open space, said impeller having an axially directed intake and a radially directed outlet into said ducts and comprising a supporting ring having a substantially axially extending flow surface, radially oriented blades having radial inner edges positioned upon said supporting ring flow surface, said blades projecting axially in the direction of the intake of said impeller toward a friction surface on the side of said friction ring away from said wheel hub, the edges of said blades in the outlet direction extending in front of said radial air ducts, said supporting ring flow surface having a concave curved configuration with the portion of said curved surface at said intake being substantially axial and the portion of said curved surface at said outlet being substantially radial, and a cap having an outer convex curved surface and an end mounted over the opening enclosed by said supporting ring, the outer surface of said cap having a smooth transition to the axial intake portion of said curved surface of said supporting ring flow surface.