GB732249A - Improvements in or relating to plain bearings - Google Patents

Abstract

732,249. Making composite bearings. GLACIER METAL CO., Ltd. Sept. 28, 1953 [Sept. 26, 1952], No. 24176/52. Classes 83 (2) and 83 (4). Stamping.-A method for the production of a plain journal bearing comprising a backing of steel, a copper-lead or equivalent metallic interlayer bonded to the backing and an overlay of soft metal and wherein the interlayer is of varying thickness lengthwise of the bearing to form a surface which tapers off on a smooth curve to the ends of the bearing is characterized in that a blank consisting of a steel backing 1, having bonded thereto a layer 2 of uniform thickness of, e.g., copper-lead, is formed to semi-cylindrical shape by bending or pressing on a die, the formed blank being then positioned on a semi-cylindrical die cavity 3 and subjected to pressure exerted through a resilient tubular mandrel 5 of high tensile alloy interposed between the blank and a pressure applying member 6, the mandrel being substantially longer than the blank, e.g. 15 per cent to 40 per cent longer, so that when pressure is applied a greater pressure is exerted on the layer of copper-lead towards the ends of the blank than at the middle to form the desired shape of interlayer by plastic flow of the material. Subsequently an overlay 17 (Fig. 7) of soft metal, e.g. babbit, tin-lead, lead-indium, &c. is applied on the crowned copper-lead layer 2a by casting or by electro-deposition. The mandrel may be smaller in diameter at the middle than at the ends and accommodated in a parallel half bore in the pressure applying member by an intermediate layer of plastic material or soft metal, e.g. lead. The mandrel may be fitted with a solid core 7 (Fig. 3) shaped to provide an annular space 8 which may be charged with fluid, e.g. liquid at sub-zero temperature. The hydrostatic pressure within the mandrel may vary with the pressure applied by the member 6 by connecting the annular space 8 with a chamber 11 between two parts 6a, 6b of the pressure applying member 6. Pressure fluid from a pump 12 normally escapes from the chamber 11 between the joint faces of the parts 6a, 6b into a groove 13 from where it drains back to a supply tank 15. During the downward stroke of the member 6 fluid can only escape from the chamber 11 if the pressure becomes excessive and therefore the pump delivers pressure fluid to the annular space 8 for reinforcing the mandrel. In the final boring the overlay at the ends of the bearing may be from 0.0005 inch to 0.008 inch thicker than at the middle. The middle 18 of the overlay may be completely removed and the bore may be slightly' curved as shown by dotted lines 19 in Fig. 8, so that the ends of the bearing are, e.g., 0.001 inch less in wall thickness than the middle. Specification 685,319 is referred to.