Engine oil pan and forming method and apparatus

摘要

An oil pan includes an oil reservoir and a pair of side walls facing the reservoir. A bulge is formed in each side wall. Each bulge defines an oil sub chamber connected to the oil reservoir. The bulges are formed integrally with the side walls by deforming the side walls outward. In other words, the bulges are not fastened to the side wall but are part of it. The oil pan is therefore easily and inexpensively formed by pressing. Further, since there is no joint between each bulge and the side wall, the oil pan has improved strength and durability.