Assembly comprising a wheel and a disc brake disc, in particular for a railway vehicle

An assembly comprising a wheel having a radially-extending web, a brake pad structure movable axially of the wheel and defining a brake pad surface, a disc structure which is coaxial with the wheel and defines a braking first surface for cooperation with the brake pad surface and defines a radially-extending friction second surface axially opposed to said first surface, the web structure defining a radially-extending third surface adjacent to said second surface for frictional engagement with said second surface upon application of the brake pad structure against the disc structure for braking, the wheel having a radially outwardly facing first circumferentially extending face and a radially inwardly facing second circumferentially extending face coaxial with the first circumferentially extending face, and a centering device centering the disc structure on the wheel and comprising centering means for a cold state of the assembly which are applied by the disc structure against said first circumferentially extending face in non-braking periods, and centering means for a hot state of the assembly which are applied by the disc structure against said second circumferentially extending face during braking periods, one of said second and third surfaces having a coefficient of friction on the other of said second and third surfaces which exceeds the coefficient of friction of said first surface on the brake pad surface.

An assembly comprising a wheel having a radially-extending web, a brake pad structure movable axially of the wheel and defining a brake pad surface, a disc structure which is coaxial with the wheel and defines a braking first surface for cooperation with the brake pad surface and defines a radially-extending friction second surface axially opposed to said first surface, the web structure defining a radially-extending third surface adjacent to said second surface for frictional engagement with said second surface upon application of the brake pad structure against the disc structure for braking, the wheel having a radially outwardly facing first circumferentially extending face and a radially inwardly facing second circumferentially extending face coaxial with the first circumferentially extending face, and a centering device centering the disc structure on the wheel and comprising centering means for a cold state of the assembly which are applied by the disc structure against said first circumferentially extending face in non-braking periods, and centering means for a hot state of the assembly which are applied by the disc structure against said second circumferentially extending face during braking periods, one of said second and third surfaces having a coefficient of friction on

• the other of said second and third surfaces which exceeds the coefficient of friction of said first surface on the brake pad surface, the wheel having a rim which defines said second circumferentially extending face, the cold centering means comprising an annular axially-extending flange of the disc structure which defines an inner surface which engages in the cold state of the assembly with said first circumferentially extending face which is in the form of an annular shoulder of the web, the hot centering means comprising an outer periphery of the disc structure, rollers which have their axes parallel to the axis of the assembly and are evenly spaced apart peripherally of said second circumferentially extending face, the rollers being interposed with a radial clearance, in the cold state of the assembly, between said second circumferentially extending face and the outer periphery of the disc structure, the disc structure comprising two rings and radial ribs interconnecting the rings, means for carrying the rollers comprising support means integral with the rim of the wheel and projecting portions located at outer ends of first ones of said ribs, radially outwardly open cavities respectively in said projecting portions and containing the rollers with a clearance radially of the wheel axis in the cold state of the assembly which is sufficient to allow radial expansion of the disc structure when braking but such as to allow the rollers to radially engage the cavities and thereby center the disc structure relative to the wheel in the hot state of the assembly.

An assembly comprising a wheel having a radially-extending web, a brake pad structure movable axially of the wheel and defining a brake pad surface, a disc structure which is coaxial with the wheel and defines a braking first surface for cooperation with the brake pad surface and defines a radially-extending friction second surface axially opposed to said first surface, the web structure defining a radially-extending third surface adjacent to said second surface for frictional engagement with said second surface upon application of the brake pad structure against the disc structure for braking, the wheel having a radially-outwardly facing first circumferentially extending face and a radially inwardly facing second circumferentially extending face coaxial with the first circumferentially extending face, and a centering device centering the disc structure on the wheel and comprising centering means for a cold state of the assembly which are applied by the disc structure against said first circumferentially extending face in non-braking periods, and centering means for a hot state of the assembly which are applied by the disc structure against said second circumferentially extending face during braking periods, the wheel having a rim which defines said second circumferentially extending face, the cold centering means comprising an annular axially-extending flange of the disc structure which defines an inner surface which engages in the cold state of the assembly with said first circumferentially extending face which is in the form of an annular shoulder of the web, the hot centering means comprising an outer periphery of the disc structure, rollers which have their axes parallel to the axis of the assembly and are evenly spaced apart peripherally of said second circumferentially extending face, the rollers being interposed with a radial clearance, in the cold state of the assembly, between said second circumferentially extending face and the outer periphery of the disc structure, the disc structure comprising two rings and radial ribs interconnecting the rings, means for carrying the rollers comprising support means integral with the rim of the wheel and projecting portions located at outer ends of first ones of said ribs, radially outwardly open cavities respectively in said projecting portions and containing the rollers with a clearance radially of the wheel axis in the cold state of the assembly which is sufficient to allow radial expansion of the disc structure when braking but such as to allow the rollers to radially engage the cavities and thereby center the disc structure relative to the wheel in the hot state of the assembly, the support means comprising a groove in the wheel, a ring engaged in the groove, a collar interposed between the ring in the groove and the rollers, and spindles fixed to the collar, the rollers being rotatably mounted on the spindles.

An assembly comprising a wheel having a radially-extending web, a brake pad structure movable axially of the wheel and defining a brake pad surface, a disc structure which is coaxial with the wheel and defines a braking first surface for cooperation with the brake pad surface and defines a radially-extending friction second surface axially opposed to said first surface, the web structure defining a radially-extending third surface adjacent to said second surface for frictional engagement with said second surface upon application of the brake pad structure against the disc structure for braking, the wheel having a radially-outwardly facing first circumferentially extending face and a radially inwardly facing second circumferentially extending face coaxial with the first circumferentially extending face, and a centering device centering the disc structure on the wheel and comprising centering means for a cold state of the assembly which are applied by the disc structure against the first circumferentially extending face in non-braking periods, and centering means for a hot state of the assembly which are applied by the disc structure against said second circumferentially extending face during braking periods, the wheel having a rim which defines said second circumferentially extending face, the cold centering means comprising an annular axially-extending flange of the disc structure which defines an inner surface which engages in the cold state of the assembly with said first circumferentially extending face which is in the form of an annular shoulder of the web, the hot centering means comprising an outer periphery of the disc structure, rollers which have their axes parallel to the axis of the assembly and are evenly spaced apart peripherally of said second circumferentially extending face, the rollers being interposed with a radial clearance, in the cold state of the assembly, between said second circumferentially extending face and the outer periphery of the disc structure, the disc structure comprising two rings and radial ribs interconnecting the rings, means for carrying the rollers comprising support means integral with the rim of the wheel and projecting portions located at outer ends of first ones of said ribs, radially outwardly open cavities respectively in said projecting portions and containing the rollers with a clearance radially of the wheel axis in the cold state of the assembly which is sufficient to allow radial expansion of the disc structure when braking but such as to allow the rollers to radially engage the cavities and thereby center the disc structure relative to the wheel in the hot state of the assembly, a projecting portion on a radially outer end of second ones of the ribs other than said first ones of said ribs, further cavities in said second ones of said ribs, compression springs disposed in said further cavities for biasing the disc structure against the wheel, means combined with the wheel for supporting one end of said springs, said further cavities having inner end walls against which end walls said springs bear.