Inner rotor-type permanent magnet motor

a permanent magnet motor and rotor-type technology, which is applied in the direction of magnetic circuits characterised by magnetic materials, electrical apparatus, dynamo-electric machines, etc., can solve the problems of insufficient assembly precision of magnetic poles, difficult to stably reduce cogging torque, and displaced magnetic poles in the circumferential direction, so as to improve rotational performance and reduce cogging torque. , the effect of increasing the (bh)max of the magn

Inactive Publication Date: 2013-04-11
MINEBEA CO LTD
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AI Technical Summary

Benefits of technology

The technical effect of this patented design allows for efficient use of space while maintaining good efficiency with smaller sizes without compromising their function properly. This results from reducing unwanted electromagnetic waves that affect the operation of certain components within these machines.

Problems solved by technology

The technical problem addressed in this patented text relates to improving the efficiency at low speeds while reducing unwanted electromagnetic forces during operation caused by the use of high-performance rare earth type magnets such as neodymium iron boron manganese sintered material. This results from the fact that certain parts called "fins," located near each pole within the interior space of the rotator's outer ring, contribute significantly towards the overall size and shape of these magnets. By adding extra pieces made up of metal into the internal part of the machine without affecting its properties, we aim to reduce the effectiveness of the resulting cogged torque due to increased stress concentration and reduced coil area.

Method used

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  • Inner rotor-type permanent magnet motor
  • Inner rotor-type permanent magnet motor
  • Inner rotor-type permanent magnet motor

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embodiments

[0038]Hereinafter, embodiments regarding minimizing the cogging torque and the back-EMF in an inner rotor-type permanent magnet motor made from annular magnetic poles where the number of pole pairs Pn is 2 according to the present invention will be explained in more detail. However, the present invention is not limited to the following embodiments.

[0039]A material composition of the magnet according to the present embodiment is as follows (the units in the following are vol. %): 32.1 of an anisotropic Sm2Fe17N3-type fine powder having a grain diameter of 3 to 5 μm and a (BH)max of 290 kJ / m3, 48.9 of anisotropic Nd2Fe14B-type particles having a grain diameter of 38 to 150 μm and a (BH)max of 270 kJ / m3, 6.2 of a novolac-type epoxy oligomer, 9.1 of linear polyamide, 1.8 of 2-phenyl-4,5-dihidroxy methyl imidazole, and 1.9 of a lubricant (pentaerythritol stearic acid triester).

[0040]The magnet in the present embodiment as described above has the following characteristics: a remanence Mr

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Abstract

A motor includes poles P having a remanence Mr of 0.9 T or more, a coercivity HcJ of 0.80 MA/m or more, and a maximum energy product (BH)max of 150 kJ/m3 or more, which sets a center point Pc of the magnetic poles in a circumferential direction on a rotor outer circumferential surface to a maximum thickness tmax, wherein when a line connecting the Pc and a rotational axis center Rc is Pc-Rc, a straight line connecting an arbitrary point Px in the circumferential direction on the rotor outer circumferential surface and the Rc is Px-Rc, an apex angle of the lines Pc-Rc and Px-Rc is θ, a number of pole pairs is Pn, a circumferential direction magnetic pole end is Pe, and a magnetic pole end biasing distance ΔLPe of the circumferential direction magnetic pole ends Pe is α×tmax (α is a coefficient).

Description

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Claims

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Application Information

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Owner MINEBEA CO LTD
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