What is the function of the semi-axle conical bushing?

- Aug 01, 2019-

In general, more than three tapered bushings are arranged equally in half axle fastening bolts with flange discs to compensate for the lateral pressure of fastening bolts. Conical bushing transforms the plane pressure of fastening bolt into the radial pressure of bolt. Bolts, nuts and conical bushing act together and play the role of half-axis positioning. Dimensional bushing usually has a groove on the dimension. When the fastening nut tightens to produce axial pressure, the bushing is compressed, and the bushing cone slides and contracts along the flange disc bushing seat, so the inner hole of the bushing is locked tightly in the shrinkage to fill the gap between the stud and the flange disc bushing seat hole. Semi-axle conical bushing must be in line with bushing seat taper, bushing inner hole should not be greater than 0.70 mm stud diameter, bushing groove width should not be less than 2.50 mm, bushing in bushing seat hole should be higher than the outer plane of half-axle flange disc 2-3 mm, and bushing should be shorter than the inner plane of flange disc 2.50 mm. In this way, the bushing will not be overcrowned because it is too long, or too low to be compressed, or the taper is not consistent and the force is not uniform, or the slot width is not enough and the holes between the bushing bore and the stud are empty.

Bushing grooving leaves shrinkage space for bushing, so that bushing can play its due role, and bushing grooving closure should never be allowed when bushing function (that is, when nuts are tightened to a certain extent). The bushing of trucks running for many years may be lost or mismatched during maintenance, so that the bushing assembly can not achieve the effect of wedging the semi-axle flange disc and stud, so that the semi-axle flange disc can move in it, and the semi-axle fastening bolt will also be loosened. On a truck, a half axle is usually equipped with 12-16 sets of fastening bolts. When the conical bushing loses its proper function, it is impossible to control wheel load and semi-axonal flange disc only by the axial pressure of other fastening bolts, which only loosen with the movement of flange disc. When all the fastening bolts are loosened, the spacing of the studs and holes increases, so the roots and holes of the studs are loosened. At the moment of the increase of the driving torque and impact of the half-axle, all the fastening studs of the half-axle will be cut off, while some studs are pulled out, the half-axle and the wheel will be disconnected resolutely, and the vehicle will not be able to drive. Sometimes when the half-axle fastening bolt is cut off, the half-axle breaks. Some guarantees often regard the semi-axle conical bushing as the cushion for the fastening nut. When the conical bushing is lacking, many spring washers are used instead. The result is useless. If the tapered bushing on the same half axle can work, the other fastening bolts can be installed with two fewer. Conversely, if all the tapered bushings or most of them do not work, the half axle and wheel will be loosened after all the other fastening bolts are replaced. That is to say, the bushing of the half axle plays a decisive role in the use of the half axle. It can not be regarded as a washer of the fastening nut.