CNC machining of various motor bases

The motor base is an important component of the motor. The rationality of its structure and processing technology has a great impact on the performance of the motor. Inadequacy of motor brooms, low frequency electromagnetic noise, vibration, etc. is mainly related to machine-based machining. Therefore, the structure of the base should be reasonably selected according to the performance requirements of the motor and processed according to the technical requirements to reduce and eliminate nonconformities caused by machining the base. Today we will organize and share some of the types of motor stands and some of the most basic technical requirements.

Motor-based basic type

• ● Depending on whether the base is a magnetic base, it can be divided into a magnetic base and a non-magnetic base. Magnetic bases are used in DC motors and pivoted synchronous motors. Non-magnetic housings are used in asynchronous motors, rotary synchronous motors, and other motors with laminated stator cores.
• ● Welding base and casting base can be divided according to various blanks of the base. The welding base is welded from steel. The casting base can be cast from cast steel, cast iron or aluminum alloy. Permeable stands are most often welded in steel or steel.
• ● Non-magnetic motor housings are generally made of gray cast iron. The cast iron motor base is low cost and conveniently processed, and its mechanical strength can meet the requirements of common small and medium size motors. High-strength cast iron or cast steel motor seats are only used in applications that require high mechanical strength, such as explosion-proof motors and marine motors.
• ● Small AC motor and micro motor. In recent years, aluminum silicon alloys or aluminum magnesium alloys have been used for die casting of motor seats. The features of this structure are that the aluminum alloy can be cast directly into the stator core, there is no need to machine the inner circle of the motor seat, some fasteners are omitted, and the small motor can be made lighter. The disadvantages are that the material price of aluminum alloy is relatively high, the mechanical strength is weak, and the abrasion resistance is low.
• ● For large motors, section steel and steel plate welded sheets are widely used due to the low output and heavy weight of the motor. Compared to cast iron stands, the weight of the weld base is lighter under the same mechanical strength and structural rigidity. When welding, no special mold is required, the cost is relatively low, the production cycle can be shortened, and the individual shape of the motor can be satisfied.
• ● Depending on the structure of the base, it can be divided into an integrated frame and an independent frame. The structural rigidity of the independent frame is weak and the processing time is long. If the assembly is improper, the entire machine will not meet the requirements. However, its unique advantage is that it is convenient to install and maintain. If the design is rational, assembly accuracy and structural stiffness are no longer constraints.The integrated motor base is relatively common and the sections are generally designed to be cylindrical. There are 2 or 4 feet at the bottom of the motor base and are powered. The cylindrical motor base has the highest workability. However, for some motors, if certain conditions limit the external dimensions and the output needs to be as high as possible, the cross section of the motor base is designed as a polygon to maximize spatial position. Often. Polygonal motor mounts are more complex to manufacture and increase processing costs.
• ● Other classification methods.Motor seats can be divided into open, protective, closed and explosion-proof types according to different protection and cooling methods. The outer surface of an enclosed explosion-proof motor base usually has a heat sink, but other motor bases do not have a heat sink. Depending on the presence or absence of feet, it can be divided into motor bases with feet (B3, B35, etc.) and motor bases without feet (V1, B5, etc.).

Technical requirements for motor-based processing

Parts machined by the motor base mainly include end stops, end faces, inner circles, foot planes, bottom holes, fixed end covers, outlet boxes and lifting bolts. For the separate type, the machine base also needs to be treated with split surfaces, screw holes and pin holes. The technical requirements that must be met during the machining of the base can be summarized as follows:

• ● The dimensional accuracy and roughness of each machined part must comply with the drawing. Both the two end stops and the inner circle have high precision and roughness requirements, and the high center dimensional precision is also accurate.
• ● The geometrical tolerance of each machined surface shall conform to the drawing. The coaxiality between the two ends of the stop and the inner circle, and the circular jump on the end faces of the two ends facing the axis, are key to the machining of the base. Of particular importance is that the maximum and minimum values ​​are within the dimensional tolerances if no geometrical tolerances are specified. The footplane must be parallel to the axis of the shaft.
• ● The distance between the foothole and the centerline of the base must be symmetrical and meet the specified tolerances.
• ● After machining the magnetic machine base, the thickness of each part of the yoke will be uniform. The poles of the poles must be equal and their positions must conform to the drawing.
• ● The split surface of the separate frame requires stable joints and reliable positioning, and can be reassembled to meet the original requirements.