Sliding bearing and crankshaft support structure

A sliding bearing that is disposed in a cylinder block and supports a journal portion of a crankshaft, the sliding bearing comprising:

• a semi-annular first split bearing having a first circumferential end surface;
• and
• a semi-annular second split bearing having a second circumferential end surface, wherein
• the first and second circumferential end surfaces contact each other,
• the first split bearing has a same outer diameter as an outer diameter of the second split bearing,
• the second split bearing has a thickness at a second circumferentially central position that is greater than a thickness of the first split bearing at a first circumferentially central position,
• the thickness of the first split bearing is decreased from the first circumferentially central position toward the first circumferential end surface,
• the thickness of the second split bearing is decreased from the second circumferentially central position toward the second circumferential end surface,
• while the sliding bearing is disposed in the cylinder block, an inner circumferential surface of the first split bearing is defined as an arcuate surface along a first reference circle that has a first center and a first radius, wherein the first center is a point that deviates from a center of a circle along an outer circumference of the sliding bearing, by a first offset amount, toward the second circumferentially central position on an inner circumferential surface of the second split bearing, and the first radius is a first reference distance from the first center to the first circumferentially central position on the inner circumferential surface of the first split bearing,
• while the sliding bearing is disposed in the cylinder block, an inner circumferential surface of the second split bearing is defined as an arcuate surface along a second reference circle that has a second center and a second radius, wherein the second center is a point that deviates from the center of the circle by a second offset amount toward the first circumferentially central position on the inner circumferential surface of the first split bearing, and the second radius is a second reference distance from the second center to the second circumferentially central position on the inner circumferential surface of the second split bearing, and
• the first offset amount is smaller than the second offset amount and the first reference distance is shorter than the second reference distance such that the first circumferential end surface has a same thickness as a thickness of the second circumferential end surface.