Classification of structural forms: divisible, integral and combined.Classification according to different manufacturing processes:Casting type —— It has high strength and rigidity, but has large mass, many machined surfaces and complicated manufacturing process, and is used for medium and heavy trucks. This design adopts casting axle housing.Steel plate welding stamping type-small quality, high material utilization rate, low manufacturing cost, suitable for mass production, cars and small and medium-sized trucks, some heavy trucks