Machining method for small NdFeB magnetic ring with high verticality requirement

Abstract

The invention discloses a machining method for a small NdFeB magnetic ring with a high verticality requirement. A semi-finished small NdFeB magnetic ring product is obtained through the steps of grinding a small magnetic pillar in a centerless grinding mode, drilling an inner hole and cutting the thickness. Surface finishing is carried out on the upper surface and the lower surface of the semi-finished small NdFeB magnetic ring product through a high-precision two-surface grinding machine. Finishing is carried out on the outer diameter of the small NdFeB magnetic ring subjected to surface finishing through a high-precision centerless grinding machine. Finally, finishing is carried out on the inner diameter of the small NdFeB magnetic ring subjected to outer diameter finishing through an automatic bearing inner circle grinding machine. A machining allowance is reserved on the semi-finished small NdFeB magnetic ring product and then is eliminated through machining, and finally, the location degree of an inner hole of the small NdFeB magnetic ring relative to the outer diameter is smaller than 0.015 mm, and the verticality, measured with the inner hole as the benchmark, of the plane of the small magnetic ring is 0.01 mm-0.03 mm. The machining method for the small NdFeB magnetic ring with the high verticality requirement has the advantages that machining is achieved through mature automatic equipment, the machining method is simple, volume production of the small NdFeB magnetic ring can be realized, and the small NdFeB magnetic ring machined through the method can meet the verticality design requirement.

Description

technical field [0001] The invention relates to a processing method for a small neodymium-iron-boron magnetic ring, in particular to a processing method for a small neodymium-iron-boron magnetic ring with high perpendicularity requirements. Background technique [0002] With the continuous improvement of motor dynamic balance requirements, a small NdFeB magnetic ring with high verticality requirements was designed and developed and put into mass production one after another. The general size and perpendicularity requirements of this kind of NdFeB small magnetic ring are: the outer diameter is φ8mm~φ20mm, the inner diameter is φ2mm~φ10mm, the thickness is 3mm~10mm, and the verticality of the small magnetic ring plane measured based on the inner hole is 0.01mm ~0.03mm. [0003] At present, the processing method of the NdFeB small magnetic ring generally includes the following steps: the step of centerless grinding the small magnetic column → the step of drilling the inner hol...

AI Technical Summary

Problems solved by technology

In the step of grinding the small magnetic column by centerless grinding, since the cylindricity and dimensional accuracy are difficult to reach below 0.01mm (usually 0.020-0.035mm) when grinding the entire small magnetic column by ordinary centerless grinding, the next drill The accuracy of drilling positioning in the inner hole step has adverse effects; in the inner hole drilling step, the small magnetic column is clamped and fixed in the triangular spring chuck, because the outer diameter of the small magnetic column after ordinary centerless grinding The accuracy is low and the cylindricity tolerance is large. There is a geometric offset of 0.01-0.03mm between the center line of the small magnetic column and the center line of the tool during clamping, and the offset between the outer diameter of the small magnetic column and the position of the inner hole after drilling It will reach 0.04 ~ 0.08mm; in the cutting thickness step, due to the sticking and feeding process, there is an uncontrollable inclination angle between the small magnetic column and the blade of the inner circle slicer, and the knife is heated unevenly during the cutting process, and the knife feed The blade tends to be skewed during cutting, so the small NdFeB magnetic ring caused by this process has a bad range of 0.08-0.16mm when measuring the verticality of the plane based on the inner hole.

Tracing it to its cause, the three processing steps in the existing NdFeB small magnetic ring processing method all have factors that cause the verticality of the NdFeB small magnetic ring (the verticality of the plane measured with the inner hole as the reference) to be too large. After accumulative stacking, the verticality of the measuring plane of the small magnetic ring based on the inner hole is far from the design value, and the defect rate of this requirement of the product is almost 100%.

Therefore, limited by the processing method of the small NdFeB magnetic ring, the user has to relax the verticality requirements for the small NdFeB magnetic ring, so that it is difficult to achieve the optimal dynamic balance of the motor and the stable operation of the motor.

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