Abstract: A sliding bearing for an internal combustion engine; the sliding bearing having a groove formed substantially circumferentially on an inner circumferential face of the sliding bearing; the width of the groove being smaller than 0.6 mm, and the ratio of the width of the groove to depth of the groove being larger than 40.

Abstract: A piston cooling device for internal combustion engines is disclosed. Lubricating oil discharged from an oil pump is led through an inlet provided on an external peripheral surface of a main journal into a first oil passage and is further delivered to an outlet provided on the opposite side of the crankshaft as the inlet. A crank pin is rotatably received by an end portion of a connecting rod, having a bearing surface interposed therebetween. A clearance is provided between the bearing surface and the crank pin. A second oil passage is provided at the connecting rod, communicating with the clearance. A port formed on the bearing surface makes the first oil passage communicate with the clearance and with the second oil passage when a crank angle comes to a range of between 0 and 90 degrees before a piston dead center position or when the inertia load applied to between the end portion of the connecting rod and the crank pin becomes is minimized.

Abstract: A sliding bearing for an internal combustion engine; the sliding bearing having a groove formed substantially circumferentially on an inner circumferential face of the sliding bearing; the width of the groove being smaller than 0.6 mm, and the ratio of the width of the groove to depth of the groove being larger than 40.