Comparative analysis of different processing advantages of the machine base
Machining is an extremely important part of the motor manufacturing process. Many of the "leiren" faults that are inexplicable or such as "flea" are mostly related to the motor frame. Here Ms. Participate in different machine base plus program comparison, explain the advantages and disadvantages of different processing methods.
Comparative analysis of different machine processing plans
The machining of the base is closely related to the manufacture of the core and the machining of the stator. When determining the machining plan, both the core manufacturing and the stator finishing must be considered. The scheme of ensuring the inner circumference of the core and the coaxiality of the ends of the core can be divided into five types: a light stop, an inner core of a light stator core, an outer circle of a light stator core, "two not only" and "two light".
●In the light stop solution, the inner and outer rings of the stator core are not machined. After being pressed into the base, the inner circumference of the iron core is positioned at the inner circumference of the iron core. In the inner scheme of the light stator core, the inner circle of the iron core is coarsely grounded with the base seat as the reference. In the outer scheme of the light stator core, the outer core of the iron core is pressed with the inner circle of the core as the reference, and pressed into the base. After that, no machining will be carried out. In the "two not only" scheme, the inner and outer rings of the stator core are not mechanically machined, and the machine seat is no longer machined after being pressed into the frame. In the "two light" scheme, the inner ring of the fine iron core and the end of the other end of the base are used as the reference for the base seat of the finished car at one end.
● According to the different machining positioning datum, the machining of the base can also be divided into two different processing schemes. The first solution is to use the stop and the end face as the positioning reference plane; the second solution is to use the foot plane and the foot hole as the positioning reference plane.
When machining, the reference plane is first machined, and then the other parts are machined by the reference plane. In the light stop scheme, the stop is deformed due to the pressing of the iron core into the machine base, and the roundness of the stop is better after the fine car stop. Eliminate the error caused by machining, core manufacturing and assembly with the fine car stop to achieve the required coaxiality. Therefore, the coaxiality of the stator is mainly determined by the accuracy and positioning error of the tire-expanding tool used in the finishing stop. When machining the base parts, the coaxiality and accuracy of the stop and the inner circle can be lowered, which is beneficial to the combination machine processing or automatic line processing. However, there is more than one light stop process, which makes it take up more than one machine. When surface and fine car stop, appropriate measures should be taken to prevent iron filings from falling into the winding ends and damaging the windings.
●In the inner scheme of the optical stator core, the coaxiality of the stator is achieved by positioning the finished car or grinding the inner circle of the iron core, which can relax the requirement of the coaxiality of the inner circle and the end of the base, and the punching The accuracy of the inner circle and the coaxiality of the inner and outer circles. However, finishing the car or grinding the inner circle of the core will increase the iron consumption and degrade the performance. Except for special cases, this scheme is generally not used.
● In the outer scheme of the optical stator core, the accuracy of the outer circle of the core and the coaxiality of the inner and outer circles of the core are achieved by the outer circle of the finished car based on the inner circle after the core is press-fitted. It can relax the accuracy of the outer circle of the punch and the requirements of the internal coaxiality. When the core is machined outside, the cutting conditions are poor, and the tool is processed with a single-blade turning tool, and the tool life is short. Since the core is not pressed after being pressed into the frame, the accuracy and coaxiality of the frame are also high.
● In the "two not only" scheme, the accuracy and coaxiality of the stator are completely dependent on the processing quality of the parts, and the processing quality of the punching piece, the core and the base are required to be high. However, the finishing process after the iron core is pressed into the machine base is omitted, and the flow line is not returned, and the work route of the workshop can be easily arranged reasonably.
● In the "two-light" scheme, the coaxiality of the stator is achieved by positioning the inner circle of the finished iron core and the other end of the stop, which can relax the inner circle precision of the punch and the coaxiality of the inner and outer circles, but The inner circle of the car core will also increase the iron consumption. This solution is sometimes used in the stator machining of medium-sized asynchronous motors.
Analysis and comparison of two different processing datum schemes
●The advantage of the first processing scheme is that the main process (processing of end face, stop and inner circle) is processed by universal horizontal lathe or vertical lathe, which has great versatility; convenient clamping and high processing efficiency; easy process Master; the circumference of the base is even; the height of the center is easy to guarantee. There are three disadvantages: (1) The two ends of the stop and the inner circle are not machined in one clamping. The error caused by positioning and clamping makes the coaxiality of one end stop and the other end stop and inner circle lower. . In particular, when the endpiece is worn so that it cannot be kept clean, the geometrical tolerance will be excessive. (2) Drilling the bottom hole after the end and inner circle processing, because the positioning of the bottom hole drilling mold is inconvenient, the distance between the foot hole and the center line of the base is prone to left and right asymmetry. (3) The positioning area of the mouth is small, and it is easy to deform due to the clamping when machining the mouth and the inner circle.
●The advantage of the second processing scheme is that the plane is used as the positioning reference plane, which is stable and reliable; the two ends of the base seat and the inner circle can be processed in one clamping, and the coaxiality is high; saving the loading and unloading time, first processing the foot after finishing The inner circle of the car can reduce the deformation of the clamping. The disadvantages are four; (1) the accuracy of the foot plane is high; (2) the inner circle has not been processed due to the processing of the foot plane, and the amount of the foot plane processing will affect the inner circle processing. It is not easy to ensure the uniformity of the wall thickness of the base and the accuracy of the center; (3) high requirements for equipment and processing technology; (4) increase working hours and costs.
This shows that the first processing scheme is easy to master, the processing efficiency is high, and the quality is guaranteed. Therefore, it is most commonly used in factories. However, when the machining of the base is developed to the automatic line, the clamping state of the workpiece at each station is required to remain unchanged.
This is easier to do when positioning in the foot plane, so it tends to use the second processing scheme. In order to ensure the high precision of the center of the machine base, the machining process of the foot plane is generally divided into two steps of rough milling and finishing milling, which are arranged in front of and behind the nozzle and inner circle processing steps.
