CHAIN CASE STRUCTURE FOR ENGINE

In a chain case structure for an engine (1)， when a chain case (8) is viewed in a direction of a crank shaft (7) of the engine (1)， both side portions of a mounting bracket unit in a width direction thereof are disposed so as to extend to one of left edge (9) and right edge (10) of the chain case (8) and to the upper edge (11) thereof， respectively， a fastener (24) adapted to fasten to the engine body (13) is mounted to a lower portion of the mounting bracket unit (13)， the cylinder unit (18， 19) is arranged under the fastener (24) with an outer circumferential surface of the cylinder unit (18，19) being coupled to the mounting bracket unit (13)， and a reinforcement rib (26-28) is disposed under the mounting bracket unit (13) so as to extend downward from the mounting bracket unit (13) by traversing the cylinder unit (18，19). Disclosed is a chain case structure of an engine， wherein， when a chain case is viewed in the crankshaft direction， both side portions of a mount bracket unit in the width direction extend to the left edge portion or the right edge portion of the chain case and the upper edge portion of the chain case， and a fastening portion to an engine main body is provided on the lower portion of the mount bracket portion. A cylinder portion of a hydraulic control valve of a variable valve mechanism is disposed below the fastening portion while the outer peripheral surface of the cylinder portion is mutually coupled to the mount bracket portion. Reinforcement ribs extend downward from the bottom of the mount bracket， across the cylinder portion.