Abstract: Disclosed is gold and platinum material having excellent mechanical strength while maintaining its high quality.The precious metal material of the present invention comprises 0.01 to 1% in weight of titanium, a rare earth metal or the like and a balance of platinum. The presence of 0.01 to 1% in weight of a selected metal provides platinum or gold material having sufficient hardness and mechanical strength while the high quality is maintained.

Abstract: In a disc brake of a type having a caliper slidably supported and having, on one side of a disc, a cylinder containing therein a piston for loading an inner pad against the disc and, on the other side of the disc, a limb portion for loading an outer pad against the disc, the flexural rigidity of the limb portion is made less on a leading side thereof located upstream with respect to the rotational direction of the disc for loading a leading or upstream side of the outer surface of the outer pad relating to a trailing side of said limb portion located downstream with respect to the rotational direction of the disc for loading a trailing or downstream side of the outer surface of the outer pad, so as to prevent frictional vibrations of the outer pad.

Abstract: A ventilated disk brake includes a pair of brake pads which is substantially the same as the prior art, and a rotor. The rotor has a brake-pad engaging portion in which a pair of brake-pad engaging walls are formed to be pressed between and by the pair of brake pads. A plurality of cooling ribs extend radially between the pair of brake-pad engaging walls. The cooling ribs are formed in such a manner that the weight distribution thereof is ununiform in the peripheral direction thereof along the brake-pad engaging portion. For example, the cooling ribs can be different in thickness, length and/or arrangement interval. such a design can be made on the basis of empirical data.