DE102017111174A1 - Interior permanent magnet motor - Google Patents

Abstract

In the internal permanent magnet type motor according to the present invention, a magnetically conductive region each having a predetermined minimum thickness is provided between a pair of magnetically non-conductive regions on the inner side of the proximal shaft end of a corresponding permanent magnet disposed in a beam form and outside the distal shaft end of the respective permanent magnet. to achieve an effect of reducing the magnetic dispersion and the cogging torque.

Description

Field of the invention

The present invention relates to a motor, and more particularly to an internal permanent magnet motor.

State of the art

In recent years, a technique of using hidden magnets inside is increasingly used for rotary motors. Since the magnets are located in the silicon steel of the rotor, flying away of the magnets can be prevented and thus the risk of demagnetization of the magnets can be reduced. However, this technique has the disadvantage that magnetic scattering occurs. Therefore, many developments in the field of rotors are concerned with technologies for reducing the magnetic scattering of magnets hidden inside.

According to the prior art, as for example by the European patent EP 2 201 663 B1 As is well-known in the art of rotor technology, symmetrical irregular pentagonal notches are provided on the side of the proximal shaft end of the magnets for reducing the magnetic scattering in a rotor having internally hidden and magnetized magnets. Alternatively, as for example from the Japanese patent JP 3 425 176 B2 In the case of a rotor with magnets hidden inside and arranged in the form of a beam, symmetrically triangular indentations are provided on the side of the proximal shaft end of the magnets. Alternatively, as in the Japanese patent JP 5 954 279 B2 In the case of a rotor with magnets hidden inside and arranged in a beam shape, portions with flat planes are provided on the side of the distal shaft end of the magnets. This can reduce the occurrence of magnetic scattering.

Although the magnetic dispersion can be reduced with the prior art described above, its effect is limited, so that it requires improvement.

Object of the invention

The object of the invention is to provide a Innenpermanentmagnetmotor, with which the magnetic scattering and the cogging torque can be reduced, whereby the control accuracy can be improved and noise is avoided.

In order to achieve the above-mentioned object, in the internal permanent magnet type motor of the present invention, a magnetically conductive region each having a predetermined minimum value is sandwiched between a pair of magnetically non-conductive regions on the inner side of the proximal shaft end of a corresponding permanent magnet disposed in a beam form and outside the distal shaft end of a corresponding permanent magnet provided.

The internal permanent magnet motor comprises a stator, a rotor and a plurality of permanent magnets. More specifically, the rotor is disposed within the stator with an air gap distance (h) between the rotor and the stator, the rotor having a core portion, a plurality of receiving recesses, and a plurality of magnetically non-conductive portions, the receiving recesses centered at the center of curvature the rotor is disposed equi - angularly distributed in the core portion, the magnetically nonconductive portions being respectively disposed in pairs at the end at which a receiving recess corresponds to the center of curvature of the rotor, each pair of magnetically nonconductive portions with respect to the center line of a corresponding receiving recess is arranged symmetrically. The core section comprises a plurality of first magnetically conductive regions which are each located between two adjacent magnetically non-conductive regions of two permanent magnets, the corresponding first magnetically conductive region each having a first spacing ( D1 ), wherein for the first distance the following formula (formula I) applies: h ≦ D1 ≦ (4 × h).
The permanent magnets are arranged in the respective receiving recesses.

In this case, the two corners of a permanent magnet located near the center of curvature are each within two mutually adjacent magnetically non-conductive regions.

In this case, all the first magnetically conductive regions each have a first distance. Preferably, two adjacent magnetically nonconductive regions each have mutually parallel edges.

In this case, only a part of the first magnetically conductive regions has a first distance. Preferably, the two respectively adjacent magnetically non-conductive regions have arcuate edges.

Here, the core portion comprises a plurality of recessed portions corresponding to the respective permanent magnets, respectively. Preferably, the bottom of the recessed portions each have an end point.

Further, the core portion includes a plurality of second magnetically conductive portions each located between the respective permanent magnets and the peripheral side surface of the core portion, the respective second magnetically conductive portions each having a second distance (FIG. D2 ), which is defined by the respective permanent magnet and a corresponding end point, wherein for the second distance the following formula (formula II) applies: (h - 0.15 mm) ≦ D2 ≦ (2 × h).

Here, the second distance is respectively the shortest distance between a corresponding permanent magnet and the peripheral side surface of the core portion.

list of figures

• 1 eine radiale Querschnittsansicht eines Ausführungsbeispiels gemäß der vorliegenden Erfindung,
• 2 eine teilweise vergrößerte Ansicht des Bereichs a aus 1,
• 3 eine teilweise vergrößerte Ansicht des Bereichs b aus 1,
• 4 eine Darstellung der Magnetfeldlinien bei einem Ausführungsbeispiel gemäß der vorliegenden Erfindung,
• 5 eine schematische Teilansicht eines weiteren Ausführungsbeispiels gemäß der vorliegenden Erfindung.

The invention will be described in more detail below with reference to the figures, which show schematic representations. It shows:

• 1 a radial cross-sectional view of an embodiment according to the present invention,
• 2 a partially enlarged view of the area a 1 .
• 3 a partially enlarged view of the area b 1 .
• 4 a representation of the magnetic field lines in an embodiment according to the present invention,
• 5 a schematic partial view of another embodiment according to the present invention.

Detailed Description of the Preferred Embodiments

It will open 1 which shows a radial cross-sectional view of an embodiment according to the present invention. The internal permanent magnet motor comprises a stator 10 , a rotor 20 and a plurality of permanent magnets 30 , The rotor 20 is in the stator 10 housed, being between the rotor 20 and the stator 10 an air gap distance h is provided. In the rotor 20 are several permanent magnets 30 arranged.

The rotor 20 has a core section 21 , several receiving recesses 22 and several magnetically nonconductive regions 23 on. The core section 21 is formed by a stack of plate bodies, which are each made of a magnetically conductive material. The several receiving recesses 22 whose center is the center of curvature of the rotor 20 is, are in the core section 21 arranged equiangularly distributed to each other. The several magnetically non-conductive areas 23 are each arranged in pairs at the end, on which a receiving recess 22 with the center of curvature of the rotor 20 Corresponds to each pair of magnetically non-conductive areas 23 with respect to the center line of a respective receiving recess 22 is arranged symmetrically.

In the following, further explanations will be given. All receiving recesses 22 are rectangular, with each pair of magnetically non - conductive areas 23 at two close to the center of curvature of the rotor 20 located corners of a respective receiving recess 22 is arranged. The respective permanent magnets 30 are each in the corresponding receiving recesses 22 arranged, wherein the two located near the center of the corners of the proximal shaft end 31 a corresponding permanent magnet 30 in the space of the adjacent magnetically non-conductive areas 23 are located.

It will open 1 . 2 and 3 referenced, wherein 2 a partially enlarged view of the area a 1 shows and 3 a partially enlarged view of the area b 1 shows. The core section 21 includes several first magnetically conductive regions 211 and a plurality of second magnetic conductive regions 212 ,

Every first magnetic conducting area 211 is in each case between two adjacent magnetically non-conductive regions 23 of two permanent magnets 30 provided and each has a first distance D1 on. Because the first distance D1 by the mutually parallel edges of the two adjacent magnetically non-conductive regions 23 is defined, are all first distances D1 between the corresponding adjacent magnetically non-conductive regions 23 equal.

Every second magnetically conductive area 212 is in each case between the corresponding permanent magnet 30 and the peripheral side surface of the core portion 21 provided, with recessed sections 24 at the corresponding with the respective permanent magnet 30 locations of the peripheral side surface of the core portion 21 are provided, wherein the bottom of the recessed sections 24 each having an end point P. The second magnetically conductive areas 212 each have a second distance D2 on, each through the distal shaft end 32 of the respective permanent magnet 30 and the corresponding end point P is defined, which means that this in each case the shortest distance between a corresponding permanent magnet 30 and the peripheral side surface of the core portion 21 equivalent.

$$\left(\text{h}-\mathrm{0,15}\text{ mm}\right)\leqq \text{D2}\leqq \left(2\times \text{h}\right)$$

In the present embodiment, the first distance applies D1 from every first magnetically conductive area 211 the following formula I, which means that the first distance is greater than or equal to the air gap distance h, which is not more than four times the air gap distance h. For the second distance D2 every other magnetically conductive area 212 the following formula II applies, ie the second distance is greater than or equal to the air gap distance h minus 0.15 mm, which is not more than twice the air gap distance h. $$\text{H}\leqq \text{<figure-callout id="1" label="D" filenames="DE102017111174A1\_0004.png" state="{{state}}">D</figure-callout>}1\leqq \left(4\times \text{H}\right)$$

$$\left(\text{H}-0.15\text{mm}\right)\leqq \text{D2}\leqq \left(2\times \text{H}\right)$$

It will be on the 4 which shows a representation of the magnetic field lines for an embodiment according to the present invention. On the basis of in 4 shown representation of the magnetic field lines can be seen that the magnetic field lines of a corresponding first magnetically conductive region 211 and a corresponding second magnetically conductive region 212 less than two are. The first magnetically conductive areas 211 and the second magnetically conductive regions 212 achieved technical effect to reduce the magnetic scattering is clearly visible. The following table gives a concrete numerical comparison. Compared to the above-mentioned patent JP 5 954 279 B2 is achieved with the embodiment according to the present invention, a better technical effect. torque constant cogging (relative value) (Rated torque ratio) conventional technique without reduction of magnetic scattering 100% 0.78% JP 5 954 279 B2 103.3% 0.52% Embodiment according to the present invention 105.2% 0.35% Embodiment according to the present invention without limitation of the first minimum thickness 95% 0.22% Embodiment according to the present invention without limitation of the second minimum thickness 107% 0.944%

The above embodiment is exemplified by ten poles, however, the present invention is not limited to this number of poles, and the technical effect of the present invention is not dependent thereon. For example, the technical effect of the present invention can also be achieved with a number of poles of four or eight.

It will open 5 which shows a schematic partial view of a further embodiment according to the present invention. In the present embodiment, each of the first magnetically conductive regions 211 in each case between two adjacent magnetically non-conductive regions 23a of two permanent magnets 30a provided, wherein the edges of the two adjacent magnetically non - conductive areas 23a arcuate. Therefore, the first distance D1 the shortest distance between two adjacent magnetically non-conductive areas 23a and is greater than or equal to the air gap distance h, the first distance D1 is not more than four times the air gap distance h. The magnetically non-conductive areas 23a Although in the present embodiment have a different shape, but with them can still under the condition that the first distance D1 meets the same conditions, the same technical effect mentioned above can be achieved. This means that there is no impairment of the achieved technical effect in a change in shape for the respective magnetically non - conductive areas.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2201663 B1 [0003]
• JP 3425176 B2 [0003]
• JP 5954279 B2 [0003, 0022]

Claims (10)

An internal permanent magnet motor comprising: a stator, a rotor disposed within the stator, wherein an air gap distance (h) is provided between the rotor and the stator, the rotor having a core portion, a plurality of receiving recesses, and a plurality of magnetically nonconductive portions the receiving recesses, the center of which is the center of curvature of the rotor, are equi - angularly distributed in the core portion, the magnetically nonconductive portions being respectively disposed in pairs at the end at which a receiving recess corresponds to the center of curvature of the rotor, each pair being of magnetic non-conductive regions is arranged symmetrically with respect to the center line of a respective receiving recess, and a plurality of permanent magnets, which are each arranged in the respective receiving recesses, characterized in that the core section has a plurality of first magnetically conductive Ber each comprising two adjacent magnetically non-conductive regions of two permanent magnets, each first magnetically conductive region s having a first distance (D1), the following formula (formula I) being valid for the first distance: h ≦ D1 ≦ (4 × h). Internal permanent magnet motor according to Claim 1 , wherein the two corners of a permanent magnet located near the center of curvature are located within two mutually adjacent magnetically non-conductive regions. Internal permanent magnet motor according to Claim 1 , wherein all first magnetically conductive regions each have a first distance. Internal permanent magnet motor according to Claim 3 , wherein the two adjacent magnetically non-conductive regions have mutually parallel edges. Internal permanent magnet motor according to Claim 1 wherein only a portion of the first magnetically conductive regions have a first distance. Internal permanent magnet motor according to Claim 5 , wherein the two adjacent magnetically non-conductive regions have arcuate edges. Internal permanent magnet motor according to Claim 1 wherein the core portion includes a plurality of recessed portions respectively corresponding to the respective permanent magnets. Internal permanent magnet motor according to Claim 7 wherein the bottom of the recessed portions has an end point. Internal permanent magnet motor according to Claim 8 wherein the core portion includes a plurality of second magnetic conductive portions respectively located between the respective permanent magnets and the peripheral side surface of the core portion, the second magnetic conductive portions each having a second distance (D2) each through a respective permanent magnet and the respective end point is defined, wherein for the second distance, the following formula (formula II) applies: (h - 0.15 mm) ≦ D2 ≦ (2 × h). Internal permanent magnet motor according to Claim 9 wherein the second distance is the shortest distance between a respective permanent magnet and the peripheral side surface of the core portion.

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