Connecting rod bearing for internal combustion engines and connecting rod bearing device

Disclosed is a connecting rod bearing for crankshafts having a pair of semi-cylindrical bearings. Circumferential grooves (CG) on the bearing inner surface extend from each circumferential end toward the circumferential center within a maximum circumferential angle of 45 degrees and divide reduced wall thickness region into two sections. Axial grooves communicating with the CG are provided along abutted ends of the bearings. Circumferential length of the CG is larger than that of the reduced region. Depth of the CG becomes gradually smaller from the end toward the center. Width of the CG is not smaller than one-quarter of a diameter of lubricant-oil outlet of internal lubricant-oil passage in a crankpin and less than the diameter. Cross-sectional area of the CG is larger than that of the axial grooves at a connection portion thereof.