The shaft is the key to the connection between the motor product and the dragged equipment, and carries the responsibility of converting the kinetic energy of the motor. During the use of motors, there will always be some cases of broken shafts.

Quality control issues of the shaft itself

Starting from theoretical analysis, we should start with controlling the diameter of the shaft and try our best to avoid sudden diameter changes. The measures taken include selecting the design dimensions and ensuring the processing technology, that is, avoiding such problems through stress relief measures.

For motors with special purposes, special materials should be used for the shaft, and if necessary, improvements can be made through forging or turning to achieve a smooth change in the shaft diameter size. This reduces the number of steps on the shaft and effectively reduces stress problems.

For welded shafts, we can prevent such problems from occurring through welding process control and necessary stress relief measures.

Association analysis

For electric motor products, the shaft belongs to the rotor part and is a rotating body. The relative guarantee of physical space is crucial, which involves the radial size control of the motor stator part's base, iron core, and end cover, as well as the selection and installation of bearings. When the stator and rotor are not concentric, it is easy to encounter the problem of uneven unilateral magnetic pulling force, which directly leads to motor vibration and low-frequency electromagnetic sound, and in severe cases, can cause sweeping problems; Given the axial and radial limitations of bearings on the rotor, when the unilateral magnetic pulling force is uneven, the shaft will naturally be subjected to radial forces, exacerbating the problem of shaft fracture.

Inappropriateness of transmission process

In the previous article, we discussed the installation and transmission of motors. If conditions permit, especially for high-power motors, it is not recommended to use belt transmission because it increases the bending moment of the shaft compared to coupling transmission. Necessary improvements should be made to the motor shaft and bearing system when necessary.

There was once a crushing and processing enterprise that used belt pulley transmission for equipment and motors, but quality failures such as shaft breakage often occurred. In response to this problem, the motor manufacturer improved the quality of the shaft and adjusted the original deep groove ball bearings to cylindrical roller bearings, which effectively controlled such issues. Compared with deep groove ball bearings with the same external dimensions, cylindrical roller bearings have line contact, while ball bearings have point contact, so the load-bearing capacity of line contact is naturally greater; Secondly, the number of rolling elements in cylindrical roller bearings is greater than that in deep groove bearings, which naturally results in a higher load-bearing capacity.

For the transmission of motors, especially in field construction, due to some practical problems objectively existing in the installation standards, special attention should be paid during the installation and use of motors.

For this type of problem, when it occurs, both the motor manufacturer and the customer should objectively analyze and improve based on data, especially for problems with regular patterns that are relatively easy to solve.