For the analysis of the cause of the broken shaft problem, it should be the principle of preventing the occurrence of the broken shaft problem to reduce and eliminate the stress point and exclude the external factors. From the analysis of the construction characteristics of the shaft, from the design stage, every effort should be made to avoid the diameter of the sudden change and the large diameter rotor of the slender shaft, from the manufacturing process, the stress should be removed through the necessary measures.
(1) Machining stress control. For motor products, most of the cylindrical billet processing, due to the construction characteristics of the shaft, basically thick in the middle of the two ends of the thin step structure, the position of the shaft diameter change is a more concentrated part of the stress, and therefore should be processed through multiple procedures to reduce the chance of stress concentration, the position of the transition fillet through the machining of the processing, reducing the processing stress is very necessary. In the actual processing, the transition fillet may be understood as an apparent quality control, its most substantial role is to avoid the stress of one of the measures.
(2) Welding stress chipping. For welding stresses, only shafts with amplitude plates are involved, i.e., amplitude plates of a certain height are welded on the basis of cylindrical blanks to reach a mating action with the rotor core. This type of shaft shows more cases of fracture.
According to the welding execution process, is divided into welding transient stress and residual stress, control of amplitude plate shaft welding stress from the welding process and the finished link to control. In order to reduce the welding transient stress, preheating of the shaft before welding is particularly important, in order to reduce the welding residual stress of the shaft, the welded shaft should be stress relieved disposal, disposal can be carried out through the ultrasonic vibration, can also be carried out through the heating method.
Welded shaft cracks generally occur in the width of the plate and the main shaft butt end, there are also longitudinal cracks, along the direction of the weld inward extension of such problems occurring in the early stage for the motor serious noise and sweeping, for the cracks are not serious check are more difficult to detect, need to be analyzed and judged through the radial run out detection method.
(3) motor installation and transmission control. For relatively large power motors, it is not recommended to use the pulley transmission, because this transmission method leads to the motor’s shaft is subject to bending moment, which can lead to serious shaft fracture.
Requirements in this regard, in the motor of the product technical conditions are specified, standardized motor manufacturers of product maintenance manuals also have instructions, but the requirements may not necessarily be implemented in the specific use. For motors that must be driven by pulleys, especially motors with relatively large specifications, it is recommended that cylindrical roller bearings be used at the driving end.
(4) The reliability of the motor mounting reference. From the actual use of the situation can be found, some of the motor mounting reference is not directly in contact with the ground, but through the frame of the way the height of the elevation, for this situation should pay special attention to the reliability of the benchmark, if the benchmark is out of balance, very easy to cause the motor and the position of the dragging equipment due to the occurrence of shaft fracture problems.
(5) Daily monitoring and measurement during motor operation. In the process of motor operation, the placement of the motor itself and the relative position of the placement of the equipment, the operation of the quality of a greater impact, should be through the periodic inspection and daily monitoring to find problems and corrections, to prevent the occurrence of quality accidents.
Post time: Jun-20-2024
