| 摘要 |
An engine comprises a crank case ( 1 ) provided with a lower opening portion ( 2 ), which is covered with an oil pan ( 3 ) from below, and with a pair of left and right oil passages which extends in a front and rear direction along left and right lateral walls ( 5 ) and ( 6 ). In this engine, the crank case ( 1 ) has the left and right lateral walls ( 5 ) and ( 6 ) provided with left and right ribs ( 12 ) and ( 13 ) extending in the front and rear direction. These left and right ribs ( 12 ) and ( 13 ) are raised inwards from the left and right lateral walls ( 5 ) and ( 6 ) of the crank case ( 1 ). In order to provide left and right oil passages ( 7 ) and ( 8 ) in these left and right ribs ( 12 ) and ( 13 ), these ribs ( 12 ) and ( 13 ) are positioned at the lower opening portion ( 2 ) of the crank case ( 1 ).
|
