To improve wear resistant and heat resistant characteristics without degrading in a foreign matter burying characteristic by forming an alloy layer having a lower hardness than a backing metal member on the bearing surface side of bearing metal, and forming an overlay layer having a lower hardness than the alloy layer on the bearing surface, and forming an exposed part of the alloy layer at both ends of bearing surface in the width direction.
An aluminium alloy containing about 20% of tin is used, in an alloy layer 11, as the material having a lower hardness than a backing metal member 16, ensuring a load resistant characteristic of bearing metal 10, and being excelent in fatigue strength and wear resistance. The bearing surface is formed of an overlay layer 12 having a lower hardness than the alloy layer 11 and being composed of material, that is, aluminium containing about 30-40% of tin excellent in a foreign matter burring characteristic and a higher heat conduction rate than a crank shaft. An exposed part 13 of alloy layer 11 is formed at the widthwise opposed wnd of bearing surface. Thereby wear rate is small at both ends of bearing surface part at the time of high speed to prevent generation of a burrel-shaped wear, and a fitting characteristic preventing generation of seizure and a foreign matter burring characteristic is ensured for a central part at which the oil film pressure of bearing surface rises, with the overlay layer 12.
