Lubricating device for internal combustion engine

An internal combustion engine, comprising:

• a cylinder head, said cylinder head having a cylinder head cover attached to an upper surface thereof;
• a cylinder block, said cylinder block being connected to a lower surface of said cylinder head at an upper surface thereof;
• a crank case divided into first and second divided crank case parts, said crank case being connected to a lower surface of said cylinder block at an end plane thereof;
• an oil pump for supplying oil in said first divided crank case part to portions to be lubricated in said second divided crank case part;
• and
• a lubricating device, said lubricating device including:
• fastening bolt hole through which a bolt passes for fastening said first and second divided crank case parts to each other, said fastening bolt hole having a diameter larger than a diameter of said bolt;
• and
• part of said bolt hole is in communication with an oil passage, said bolt hole and said oil passage forming a portion of an oil supply passage in communication with said second divided crank case part, said oil supply passage includes an oil groove in communication with said bolt hole, said oil groove being formed in said end plane of said crank case.

A four-wheel vehicle, comprising:

• a pair of left and right wheels mounted for rotation about a front portion and a rear portion of a body frame, respectively;
• a power unit including an engine and a transmission, said power unit being supported at a central portion of said body frame;
• front and rear shafts for transferring power from said power unit to said front and rear wheels, respectively;
• and
• wherein said engine further includes:
• a cylinder head, said cylinder head having a cylinder head cover attached to an upper surface thereof;
• a cylinder block, said cylinder block being connected to a lower surface of said cylinder head at an upper surface thereof;
• a crank case divided into first and second divided crank case parts, said crank case being connected to a lower surface of said cylinder block at an end plane thereof,
• an oil pump for supplying oil in said first divided crank case part to portions to be lubricated in said second divided crank case part;
• and
• a lubricating device, said lubricating device including:
• a fastening bolt hole through which a bolt passes for fastening said first and second divided crank case parts to each other, said fastening bolt hole having a diameter larger than a diameter of said bolt;
• and
• part of said bolt hole is in communication with an oil passage, said bolt hole and said oil passage forming a portion of an oil supply passage in communication with said second divided crank case part, said oil supply passage includes an oil groove in communication with said bolt hole, said oil groove being formed in said end plane of said crank case.