The shaft break of the hydraulic oil pump motor occurs at the root of the shaft extension and at the root of the bearing at the shaft extension. If the motor has a shaft fracture phenomenon, macroscopic observation and microscopic analysis of the shaft fracture surface should be performed to find out the location and cause of the fracture crack source. The following Dalan motor editor will take you to learn this knowledge.
The fracture surface of the shaft is in the transition fillet area (the root of the bearing installation) at the bearing installation location on the shaft. If the fracture surface is neat and perpendicular to the axial direction, there is no necking and plastic deformation. The fracture fatigue band is obvious, extending from the outer circle to the center, and the final instantaneous fracture area is less than 15% of the axial cross-sectional area.
Motor shaft mechanics calculation and analysis Because the motor shaft is a stepped shaft, the torque and stress at different stepped sections are different. When the motor is running, the shaft is subjected to bending and torsion moments. If a certain step section is subjected to excessive stress, cracks and fractures may germinate at the transition arc of the step section first. Therefore, find the dangerous section of the motor shaft. It is important to determine the cause of shaft fracture.
The reason for the broken motor shaft is summarized as follows:
Motor shaft fracture is the result of superposition of multiple factors. This article lists the most common reasons:
(1) Manufacturing potential quality problems
The fracture form of the motor shaft belongs to low-stress rotating bending fatigue fracture. The fundamental reason is that there are defects in the production and processing of the motor shaft. For example, there is no process control requirement for the shaft shoulder transition fillet, no heat treatment after welding, and super-inclusions in the surfacing layer, resulting in The stress concentration of the shoulder fillet produces fatigue cracking under the action of the rotating bending moment, which ultimately leads to the fracture of the motor shaft.
(2) Installation problems
If the pulley is used for transmission, the belt tension is too large (greater than the belt manufacturer's recommended value), which increases the load on the motor shaft and is a contributing factor to the motor shaft fracture. If the motor installed with the coupling cannot guarantee the coaxiality of the motor and the axis of the equipment, it will also cause fatigue and fracture of the shaft.
(3) The web axis breaks
Except for installation factors, irregular cracks often occur at the welding position of the web. Most motor manufacturers solve the problems of such shafts by processing stress grooves through the annealing process and at both ends of the web and the main shaft. Broken shaft problem.
----- Responsible Editor: Dalan Oil Pump Motor 02-Procurement Consultant
Copyright http: / (Dalan Motor) Reprint, please indicate the source
================================================== ================================================== ======
