Chain case structure of engine

Abstract

A chain case structure of an engine includes an oil pump is disposed in a chain case and driven by a crankshaft of the engine and an oil pump case. The oil pump case includes an oil strainer mounting portion, an oil suction passage communicating the oil strainer mounting portion with a pump chamber, and a chain guide portion protruding toward the one end in the crankshaft direction of the engine and extending along an outer periphery of a timing chain. The oil strainer mounting portion is disposed below the chain guide portion, the oil suction passage portion is expanded from a wall surface of the oil pump case toward the engine and extended toward the chain guide portion, and the oil strainer mounting portion and the chain guide portion are connected by the oil suction passage portion.

1 . A chain case structure of an engine having a cylinder block, a crankshaft supported by the cylinder block, a crank sprocket mounted to one end of the crankshaft, a crank gear mounted to another end thereof, and a timing chain wound around the crank sprocket and the crank gear, the chain case structure being mounted to an axial one end of the engine crankshaft,
 the chain case structure comprising:   a chain case;   an oil pump that is disposed in the chain case and driven by the crankshaft of the engine; and   an oil pump case including a pump chamber and covering the oil pump,   wherein the oil pump case further includes an oil strainer mounting portion, an oil suction passage communicating the oil strainer mounting portion with the pump chamber, and a chain guide portion protruding toward the one end in the crankshaft direction of the engine and extending along an outer periphery of the timing chain wound around the crank sprocket, and   wherein the oil strainer mounting portion is disposed below the chain guide portion, the oil suction passage portion is expanded from a wall surface of the oil pump case toward the engine and extended toward the chain guide portion, and the oil strainer mounting portion and the chain guide portion are connected by the oil suction passage portion.   
     
     
         2 . The chain case structure of an engine according to  claim 1 , wherein the oil suction passage portion is configured to have a width substantially equal to a width of the chain guide portion when the oil pump case is seen from the crankshaft direction of the engine. 
     
     
         3 . The chain case structure of an engine according to  claim 2 , wherein the oil pump case includes a pressure regulating valve, a housing accommodating the pressure regulating valve and a fastening portion fastened to the chain case and disposed between the pressure regulating valve housing and the chain guide portion so that the chain guide portion is connected to the pressure regulating valve housing through the fastening portion. 
     
     
         4 . The chain case structure of an engine according to  claim 3 , wherein the oil strainer mounting portion and the pressure regulating valve housing are connected by a reinforcing rib that is connected to the chain guide portion through the fastening portion.