Also known as a winch box, it is a box part that supports and lubricates bearings. At the same time, bear the axial and radial forces generated by the equipment during operation. In equipment with rotating shafts, the shaft is generally supported and rotated by bearings, which are installed in a bearing box filled with lubricating oil. During operation, bearings are used to obtain lubrication. At the same time, various forces received by the shaft during operation will also be transmitted to the bearing box, which will bear the load. The material of the bearing box is generally cast iron and cast steel. Mostly used for wheel sets.

In terms of its function, it should be support, which is literally used to support the shaft, but this is only part of its function. The essence of support is to be able to bear radial loads. It can also be understood as being used to fix the shaft. The automatic selection of bearing quick, easy and excellent is included. It is to fix the shaft so that it can only rotate and control its axial and radial movement.