GB1325646A - Disc brake - Google Patents

Abstract

1325646 Disc brakes M G WHITFIELD 28 March 1972 14433/72 Heading F2E In a disc brake including a brake disc 26 having a hub 10 for mounting on, so as to rotate with, a rotatable device to which braking is to be applied, friction members 12 to engage external surfaces of the brake disc and provide resistance to the rotation thereof, the brake disc has therein a plurality of passages 42 extending radially between the hub and the outer periphery of the brake disc, said passages being permanently closed and sealed to isolate them from the exterior of the disc and containing a low melting point material. The passages extend radially inwardly beyond the external surfaces engaged by the friction members, the low melting point material contained in said passages being a metal or alloy also having a low vaporization point and, the metal or alloy in each passage, when solid, occupying less than half the volume of each said passage, so that, when the metal or alloy is melted by heat generated by friction in the brake, thrown outward by centrifugal force, and vaporized by further heating, the vapour can return radially inwardly along the passages, condense at the cooler inner portion of the disc, and return to the outer peripheral portion in liquid form to provide continuous absorption of heat by repeated vaporization. As shown, the disc 26 comprises plates 30, 32 moulded from sintered metal one or both of which is or are, provided with grooves 36 which, when the plates are assembled together, form radial passages 42. Each passage has introduced therein a metal, such as sodium, of low melting and vaporization point in molten or solid form. In a modification, the passages are formed by tubes 50, Fig. 4, the flattened ends of each of which are disposed at right angles to each other.