| 摘要 |
PROBLEM TO BE SOLVED: To provide a crankshaft bearing device of a multi-cylinder engine, capable of reducing the slide resistance of a bearing section and suppressing occurrence of oscillation due to rotational misalignment of a crankshaft.SOLUTION: A plurality of bearing sections including bearing metals bearing respective main shaft sections of a crankshaft includes a mixture of first bearing metals and second bearing metals 12a and 13a different in shape. A clearance between an inner circumferential surface of each first bearing metal and an outer circumferential surface of each main shaft section is set to a predetermined reference value in a piston reciprocating motion direction, and a shape of the inner circumferential surface in an axial direction from a shaft end is prepared into a generally circular shape so that the clearance is equal to a first set value slightly larger than the reference value in an orthogonal direction orthogonal to the piston reciprocating motion direction. A clearance between an inner circumferential surface of each of the second bearing metals 12a and 13a and the outer circumferential surface of a main shaft section 51a is set to the reference value C4 in the piston reciprocating motion direction, and a shape of the inner circumferential surface in the axial direction from a shaft end is prepared into an elliptical shape so that the clearance is equal to a second set value C13 larger than the first set value by a predetermined amount in the orthogonal direction. |
