The half-shafts commonly used in modern automobiles have two types, full-floating and semi-floating, according to their different bearing types. (There are also three types, namely full floating, 3/4 floating, and semi-floating)
Full floating axle shaft
When working, it only bears torque, and its two ends do not bear any force and bending moment, which is called full floating half shaft. The outer end flange of the half shaft is fastened to the wheel hub with bolts, and the wheel hub is mounted on the half shaft sleeve through two farther apart bearings. Structurally, the inner end of the fully floating semi-shaft is provided with splines, the outer end is provided with flanges, and the flanges are provided with several holes. It is widely used in commercial vehicles because of its reliable work.
3/4 floating axle shaft
In addition to bearing the full torque, it also bears a part of the bending moment. The most prominent structural feature of the 3/4 floating axle shaft is that there is only one bearing at the outer end of the axle shaft, which supports the wheel hub. Due to the poor support rigidity of a bearing, this half-shaft not only bears the torque, but also bears the bending moment caused by the vertical force, the driving force and the lateral force between the wheel and the road surface. 3/4 floating axle shafts are rarely used in automobiles.
Semi-floating half shaft
The semi-floating axle shaft is directly supported on the bearing located in the inner hole of the outer end of the axle housing with the journal close to the outer end, and the end of the axle shaft is fixedly connected with the hub by the journal with the tapered surface and the key, or directly with the flange. The wheel disc and the brake hub are connected. Therefore, in addition to the transmission torque, it also bears the bending moment caused by the vertical force, driving force and lateral force from the wheel. Due to its simple structure, small quality and low cost, the semi-floating axle shaft is used in passenger cars and some of the same vehicles.