What are the technical requirements for motor shaft machining?
There are many key dimensions involved in the machining of the motor shaft. For example, the shaft extension, the bearing position and the core position are related to the size of the fitting and installation, and the central hole of the reference uniqueness. Any one fails or fails to meet the design expectations. , will be a great hidden danger. In order to prevent unqualified or deviate from design expectations, Ms. Participate in the experience of various manufacturers and talk about shaft machining.
Motor shaft main size element control
The accuracy and roughness of the shaft are higher than other parts, and the shaft and other parts are also tightly matched. The following elements must be grasped during processing.
● The coaxiality of the working surface. The main working surfaces are the bearing position (the surface that mates with the bearing) and the shaft extension (the surface that mates with the drive wheel). If the radial runout (eccentricity) of the bearing surface on the bearing surface is too large, vibration and noise will be generated during the operation of the motor. In addition, the radial thrust of the rotor core, the collector ring, the commutator and the fan is excessively large. At the same time, although the outer circle of these components can be corrected when the rotor is finished, it will cause more initial unbalance, if the rotor core, the collector ring, the commutator and the fan are assembled to the shaft after finishing, That is not, the path of these components is too large, which will greatly affect the reliability of the motor operation.
● Dimensional accuracy and cylindricity control of the mating part. The dimensional accuracy and shape accuracy of the shaft extension, bearing position and core position should be accurate. Otherwise, assembly difficulties will occur, and even parts damage, loose bearings or inflexible operation, and excessive bearing temperature rise will occur.
● Roughness control of the shaft. The roughness of the mating surface is not high, it is easy to wear, and the mating part will loosen. The roughness of the non-mating surface is too low, which will reduce the fatigue strength of the shaft.
● The rounded corners of the shoulder and the overrunning groove of the grinding wheel should be machined according to the specified size. Too small a corner radius and an excessively deep grinding wheel over-travel will reduce the strength of the shaft; excessive corner radius will make the end face of the fitting not stable. The grinding wheel overrunning groove is necessary to prevent the side of the grinding wheel from rubbing against the shoulder when grinding. The size of the overpass is selected according to the mechanical industry standard.
● The symmetry of the keyway to the reference surface axis should not be excessive, otherwise it will cause assembly difficulties. For the key groove of the hot press fit part, it is necessary to meet the drawing requirements. Otherwise, in the hot press assembly, the workpiece cannot be placed in the proper position due to the symmetry. The workpieces that are hot-pressed are difficult to disassemble after being placed on the workpiece, often resulting in waste.
● The distance between the two bearing gears should be accurate. Failure to do so may cause axial deflection of the rotor core or jamming of the assembled bearing.
Basic machining process of the shaft
The machining process of the shaft can be divided into two stages: preliminary machining and forming machining. The preparatory processing of the shaft includes round steel straightening, blank blanking, flat end face and center hole. The purpose of the preparatory machining is to provide acceptable gross damage and to make a process positioning reference for forming. Forming processing includes roughing, semi-finishing, finishing, grinding, rounding, and milling. The purpose of the forming process is to machine the blank into the shape and size of the structural design.
The straightening of the round steel, the unloading of the wool, etc. are carried out before the blank enters the machining process, so as to facilitate the transportation within the factory and reduce the footprint of the machined area. The flat end face, the center hole and the forming process are all carried out in a machining process to organize the flow operation.
Different motor manufacturers and different organization modes are set by their own product characteristics and factory characteristics, but they are always in the same place. Grasping the streamlined process is the essence of large-scale lean students.
