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WO2025191619A1 - Rotor for electric machine and electric machine comprising such rotor - Google Patents

Rotor for electric machine and electric machine comprising such rotor

Info

Publication number
WO2025191619A1
WO2025191619A1 PCT/IT2025/050048 IT2025050048W WO2025191619A1 WO 2025191619 A1 WO2025191619 A1 WO 2025191619A1 IT 2025050048 W IT2025050048 W IT 2025050048W WO 2025191619 A1 WO2025191619 A1 WO 2025191619A1
Authority
WO
WIPO (PCT)
Prior art keywords
flow barrier
opening angle
whose
external
internal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/IT2025/050048
Other languages
French (fr)
Inventor
Davide Bettoni
Luca FAVRE
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mavel EDT SpA
Original Assignee
Mavel EDT SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mavel EDT SpA filed Critical Mavel EDT SpA
Publication of WO2025191619A1 publication Critical patent/WO2025191619A1/en
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
    • H02K1/276—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
    • H02K1/2766—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] having a flux concentration effect
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
    • H02K29/03—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2213/00—Specific aspects, not otherwise provided for and not covered by codes H02K2201/00 - H02K2211/00
    • H02K2213/03—Machines characterised by numerical values, ranges, mathematical expressions or similar information

Definitions

  • the present invention relates to a rotor for an electric machine , and to an electric machine comprising said rotor .
  • the invention relates to a rotor for a synchronous reluctance electric machine , of the permanent magnet type .
  • An electric machine typically comprises a fixed part , the stator, and a moving part , the rotor, arranged coaxially one inside the other .
  • the rotor is located inside the stator, which comprises electric coils capable of generating a magnetic field that allows the rotor to rotate .
  • the rotor typically comprises a body consisting of a pack of laminations and positioned on a rotation shaft .
  • the laminations comprise seats for permanent magnets .
  • An obj ect of the present invention is obtaining a rotor for an electric machine and an electric machine that guarantee better ef ficiency, allowing to obtain better performance with a high "air gap" , which entails greater machining tolerances of the rotor and lower costs .
  • Another obj ect of the present invention is reducing torque ripple and back-electromotive force harmonics .
  • FIG . 1 shows a front view of a rotor for an electric machine according to the invention
  • FIG . 2 shows enlarged details of a rotor for an electric machine according to the invention
  • FIG . 3 shows a partial view of two poles and an enlarged detail of a rotor for an electric machine according to the invention.
  • FIG . 4 shows a partial view of two poles of a rotor for an electric machine according to the invention .
  • the rotor 1 for an electric machine comprises : a rotation shaft ; a lamellar pack fixed on the rotation shaft and comprising a plurality of identical laminations 3 , comprising a central hole 2 crossed by the rotation shaft and a plurality of axial cavities 6 , 7 , 8 that cross the laminations 3 from side to side .
  • each sheet 3 comprises : a plurality of pairs of first 6 and second 7 axial cavities , preferably of trapezoidal , rectangular, parallelogram or square shape , arranged radially one below the other and spaced apart from each other, inclined with respect to the radial direction; the sheets 3 also comprise magnetic flow generators inserted in the first 6 and second 7 axial cavities , preferably permanent magnets in the form of bars , and a plurality of third axial cavities 8 having an inclined direction with respect to the radial direction and with respect to the direction of the second axial cavities 7 , said third axial cavities 8 starting from the second axial cavities 7 to arrive in the vicinity of the edge of the sheet 3 .
  • each sheet 3 comprises a plurality of pairs of first 6 and second 7 axial cavities inclined and arranged symmetrically with respect to a radius Rl , R2 of the sheet 3 passing through the centre C of rotation of the rotor 1 , each of said first 6 and second 7 axial cavities starts from another first 6 and second 7 axial cavities to arrive respectively in proximity to the edge of the sheet 3 and in proximity to the third axial cavities 8 incl ined with respect to the radial direction and with respect to the direction of the second axial cavities 7 .
  • said first axial cavities 6 comprise a first surface 31 substantially parallel to the edge of the sheet 3 , connected with a first lateral surface 41 and a second lateral surface 51 by means of at least one hollow sector 35 to form a protrusion; furthermore , the first surface 31 is connected with the first lateral surface 41 and with the second lateral surface 51 by means of two connecting radii R .
  • the first surface 31 is connected to the first lateral surface 41 by the hollow sector 35 and the first lateral surface 41 and the second lateral surface 51 are parallel to each other .
  • the third axial cavities 8 having an inclined radial direction, have a first surface 12 substantially parallel to the edge of the sheet metal 3 , connected to a first lateral surface 22 and a second lateral surface 23 by means of two connecting radii R, as shown in the enlarged detai l of figure 3 ; furthermore , the third axial cavities 8 have a second surface 18 substantially parallel to a first surface 32 of the second axial cavities 7 , said first surface 32 being connected to a first lateral surface 42 and a second lateral surface 52 by means of at least one hollow sector 36 to form a protrusion; furthermore , the first surface 32 is connected to the first lateral surface 42 and to the second lateral surface 52 by means of two connecting radii R; preferably, the first surface 32 is connected to the first lateral surface 42 by means of the hollow sector 36 , furthermore the first lateral surface 42 and the second lateral surface 52 are parallel to each other .
  • each of said first 6 and second 7 axial cavities comprises a second surface 34 connected to the first lateral surface 41 , 42 and to the second lateral surface 51 , 52 of said first 6 or second 7 inclined axial cavities by means o f at least one hollow sector 38 to form a protrusion .
  • the rotor 1 comprises six magnetic poles 13 , 14 , each comprising three flow barriers
  • each flow barrier 9 , 10 , 11 comprises : a pair of axial cavities 6 , 7 inclined and arranged symmetrically with respect to a radius Rl , R2 of the lamination 3 passing through the centre C of rotation of the rotor 1 and suitable for hous ing a flow generator, preferably a permanent magnet .
  • each flow barrier 9 comprises : a pair of axial cavities 6 , 7 inclined and arranged symmetrically with respect to a radius Rl , R2 of the lamination 3 passing through the centre C of rotation of the rotor 1 and suitable for hous ing a flow generator, preferably a permanent magnet .
  • the external flow barrier 11 comprises a pair of first axial cavities 6 inclined and arranged symmetrically with respect to a radius Rl , R2 of the lamination 3 passing through the centre C of rotation of the rotor 1 and suitable for hosting a flow generator, preferably a permanent magnet ; said pair of first axial cavities 6 forms a figure similar to a "V" , whose inclined arms are formed by the pair of f irst axial cavities 6 having their respective second surfaces 34 parallel to each other in the direction of the radius Rl , R2 of the lamination 3 .
  • the intermediate flow barrier 10 and the internal flow barrier 9 comprise : a pair of second axial cavities 7 inclined and arranged symmetrically with respect to a radius Rl , R2 of the lamination 3 passing through the centre C of rotation of the rotor 1 and suitable for housing a flow generator, preferably a permanent magnet , and a pair of third axial cavities 8 inclined and arranged symmetrically with respect to said second axial cavities 7 .
  • each intermediate f low barrier 10 and internal flow barrier 9 forms a figure similar to a "V" , the inclined arms of which are formed by the pair of second axial cavities 7 and third axial cavities 8 , said second axial cavities 7 having their respective second surfaces 34 parallel to each other in the direction of the radius Rl , R2 of the lamination 3 .
  • Each flow barrier 9 , 10 , 11 corresponds to an opening angle 013 which defines the width of the "V" shape ( Fig . 4 ) .
  • opening angles 013 are identi fied by two straight lines , each passing through the second lateral surfaces 51, 52 of the first 6 and second 7 inclined axial cavities of each flow barrier 9, 10, 11.
  • the rotor 1 comprises three primary magnetic poles 13 and three secondary magnetic poles 14, each comprising three flow barriers 9, 10, 11.
  • each of the three primary magnetic poles 13 preferably comprises an external flow barrier 11 whose opening angle 013 is substantially equal to 124° ⁇ 10°, an intermediate flow barrier 10 whose opening angle 013 is substantially equal to 124° ⁇ 10°, an internal flow barrier 9 whose opening angle 013 is substantially equal to 124° ⁇ 10°;
  • each of the three secondary magnetic poles 14 preferably comprises an external flow barrier 11 whose opening angle 013 is substantially equal to 124° ⁇ 10°, an intermediate flow barrier 10 whose opening angle 013 is substantially equal to 124° ⁇ 10°, an internal flow barrier 9 whose opening angle 013 is substantially equal to 124° ⁇ 10°.
  • the amplitude of the three flow barriers 9, 10, 11 of each primary and secondary magnetic pole 13, 14 is defined by identifying the opening angles 01, 02, ..., 012, included between two straight lines projected from the theoretical centre C of rotation of the rotor 1 and each passing through a connection point R of the surfaces 31 and 12, substantially parallel to the edge of the sheet metal 3, of each first and third inclined axial cavity 6, 8, respectively with the first and second lateral surfaces 41, 51 of each first inclined axial cavity 6 and with the first and second lateral surfaces 22, 23 of each third inclined axial cavity 8.
  • an internal opening angle 01, 03, 05, 07, 09, 011 is identified, included between two straight lines projected from the centre C of rotation of the rotor 1 and passing through the connection point R of the surfaces 31, 12 substantially parallel to the edge of the sheet metal 3 of each first 6 and third 8 inclined axial cavity, respectively with the second lateral surface 51 of each first inclined axial cavity 6 and with the second lateral surface 23 of each third inclined axial cavity 8, and an external opening angle 02, 04, 06, 08, 010, 012 is also identified, included between two straight lines projected from the centre C of rotation of the rotor 1 and passing through the connection point R of the surfaces 31 , 12 substantially parallel to the edge of the sheet metal 3 of each first 6 and third 8 inclined axial cavity, respectively with the first lateral surface 41 of each first axial cavity 6 inclined and with the first lateral surface 22 of each third axial cavity 8 inclined .
  • the Table 1 below lists the values of the opening angles 01 , 02 , ..., 06 for three primary magnetic poles 13 and the values of the opening angles 07 , 08 , ..., 012 for three secondary magnetic poles 14 of the rotor 1 .
  • the secondary magnetic poles 14 each comprise: an external flow barrier 11 whose external opening angle 08 is between 27° 83' and 31° 83', preferably substantially equal to 29° 83' ; an intermediate flow barrier 10 whose external opening angle 010 is between 42° 95' and 46° 95' , preferably substantially equal to 44° 95' ; an internal flow barrier 9 whose external opening angle 012 is between 57° 11' and 61° 11' , preferably substantially equal to 59° 11' ; the primary magnetic poles 13 each comprise: an external flow barrier 11 whose external opening angle 02 is between 23° 59' and 27° 59' , preferably substantially equal to 25° 59' ; an intermediate flow barrier 10 whose external opening angle 04 is between 34° 94' and 38° 94' , preferably substantially equal to 36° 94' ; an internal flow barrier 9 whose external opening angle 06 is between 49° 47' and 53° 47' , preferably substantially equal to 51° 47' .
  • the secondary magnetic poles 14 each comprise: an external flow barrier 11 whose internal opening angle 07 is between 21° 73' and 25° 73' , preferably substantially equal to 23° 73' ; an intermediate flow barrier 10 whose internal opening angle 09 is between 36° 55' and 40° 55' , preferably substantially equal to 38° 55' ; an internal flow barrier 9 whose internal opening angle 011 is between 50° 65' and 54° 65' , preferably substantially equal to 52° 65' ;
  • the primary magnetic poles 13 each comprise: an external flow barrier 11 whose internal opening angle 01 is between 18° 16' and 22° 16' , preferably substantially equal to 20° 16' ; an intermediate flow barrier 10 whose internal opening angle 03 is between 28° 93' and 32° 93' , preferably substantially equal to 30° 93' ; an internal flow barrier 9 whose internal opening angle 05 is between 43° 86' and 47° 86' , preferably substantially equal to 45° 86' .
  • the radii of connection R between the surface 12 substantially parallel to the edge of the lamination 3 and the first 22 or second lateral surface 23 of each inclined third axial cavity 8 are included within the range 0.2 - 1 mm.
  • the radii of connection R between the first surface 31 substantially parallel to the edge of the lamination 3 and the first 41 or second 51 lateral surface of each inclined first axial cavity 6 are included within the range 0.2 - 1 mm.
  • the rotor 1 comprises primary magnetic poles 13 and secondary magnetic poles 14 arranged alternately with respect to each other.
  • the flow barriers 9, 10, 11 of two consecutive magnetic poles 13, 14 are asymmetrical to each other and this limits , compared to the electrical machines of the prior art , the torque ripple and the harmonics of counter-electromotive force .
  • an electric machine comprises a fixed part , the stator, and a moving part , the rotor, arranged coaxially one inside the other .
  • the rotor is located inside the stator, which comprises electric coils capable of generating a magnetic field that allows the rotor to rotate .
  • the electric machine according to the invention also comprises the rotor 1 described above , and between the rotor 1 and the stator an air gap of thickness between 0 . 5 mm and 1 . 5 mm .
  • the rotor and the electric machine of the invention allow to obtain a better efficiency and better performance with a high "air gap" , which entails greater machining tolerances of the rotor and lower costs .
  • Another advantage of the present invention is to reduce the torque ripple and the harmonics of counter-electromotive force.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)

Abstract

A rotor (1) for an electric machine is described comprising: a rotation shaft; a lamellar pack fixed on the rotation shaft and comprising a plurality of laminations (3) comprising three pairs of primary (13) and secondary (14) magnetic poles, each magnetic pole comprising an external flow barrier (11), an intermediate flow barrier (10) and an internal flow barrier (9).

Description

ROTOR FOR ELECTRIC MACHINE AND ELECTRIC MACHINE
COMPRISING SUCH ROTOR
The present invention relates to a rotor for an electric machine , and to an electric machine comprising said rotor .
In particular, the invention relates to a rotor for a synchronous reluctance electric machine , of the permanent magnet type .
An electric machine typically comprises a fixed part , the stator, and a moving part , the rotor, arranged coaxially one inside the other . Typically, the rotor is located inside the stator, which comprises electric coils capable of generating a magnetic field that allows the rotor to rotate . The rotor typically comprises a body consisting of a pack of laminations and positioned on a rotation shaft . In permanent magnet electric motors , the laminations comprise seats for permanent magnets .
In electric machines , and in particular in high-performance permanent magnet electric motors , an important parameter is the air gap between the rotor and the stator : the smaller the air gap, the better the performance of the electric machine , but this requires high-precision and expensive machining . A problem with synchronous reluctance electric machines , of the permanent magnet type , is the vibrations generated by torque ripples and back-electromotive force harmonics , which can generate rotor vibrations and high losses .
Documents US 2013/ 147299 , US 10778054 , US 2023/ 198325 , US 2016/ 365762 describe rotors of electric machines according to the prior art .
An obj ect of the present invention is obtaining a rotor for an electric machine and an electric machine that guarantee better ef ficiency, allowing to obtain better performance with a high "air gap" , which entails greater machining tolerances of the rotor and lower costs .
Another obj ect of the present invention is reducing torque ripple and back-electromotive force harmonics .
The above and other obj ects and advantages of the invention, as will result from the following description, are achieved with a rotor for an electric machine and an electric machine as described in the independent claims .
Preferred embodiments and non-trivial variations of the present invention form the subj ect matter of the dependent claims .
It is understood that all appended claims form an integral part of the present description .
It will be immediately obvious that innumerable variations and modi fications can be made to what is described ( for example relating to shape , dimensions , arrangements and parts with equivalent functionality) without departing from the scope of the invention as appears from the appended claims .
The present invention will be better described by some preferred embodiments , provided by way of example and not of limitation, with reference to the attached drawings , in which :
- FIG . 1 shows a front view of a rotor for an electric machine according to the invention;
- FIG . 2 shows enlarged details of a rotor for an electric machine according to the invention;
- FIG . 3 shows a partial view of two poles and an enlarged detail of a rotor for an electric machine according to the invention; and
- FIG . 4 shows a partial view of two poles of a rotor for an electric machine according to the invention .
With reference to the figures , the rotor 1 for an electric machine according to the invention comprises : a rotation shaft ; a lamellar pack fixed on the rotation shaft and compris ing a plurality of identical laminations 3 , comprising a central hole 2 crossed by the rotation shaft and a plurality of axial cavities 6 , 7 , 8 that cross the laminations 3 from side to side . In particular, each sheet 3 comprises : a plurality of pairs of first 6 and second 7 axial cavities , preferably of trapezoidal , rectangular, parallelogram or square shape , arranged radially one below the other and spaced apart from each other, inclined with respect to the radial direction; the sheets 3 also comprise magnetic flow generators inserted in the first 6 and second 7 axial cavities , preferably permanent magnets in the form of bars , and a plurality of third axial cavities 8 having an inclined direction with respect to the radial direction and with respect to the direction of the second axial cavities 7 , said third axial cavities 8 starting from the second axial cavities 7 to arrive in the vicinity of the edge of the sheet 3 . Preferably, each sheet 3 comprises a plurality of pairs of first 6 and second 7 axial cavities inclined and arranged symmetrically with respect to a radius Rl , R2 of the sheet 3 passing through the centre C of rotation of the rotor 1 , each of said first 6 and second 7 axial cavities starts from another first 6 and second 7 axial cavities to arrive respectively in proximity to the edge of the sheet 3 and in proximity to the third axial cavities 8 incl ined with respect to the radial direction and with respect to the direction of the second axial cavities 7 .
Preferably, said first axial cavities 6 comprise a first surface 31 substantially parallel to the edge of the sheet 3 , connected with a first lateral surface 41 and a second lateral surface 51 by means of at least one hollow sector 35 to form a protrusion; furthermore , the first surface 31 is connected with the first lateral surface 41 and with the second lateral surface 51 by means of two connecting radii R . Preferably, the first surface 31 is connected to the first lateral surface 41 by the hollow sector 35 and the first lateral surface 41 and the second lateral surface 51 are parallel to each other . The third axial cavities 8 , having an inclined radial direction, have a first surface 12 substantially parallel to the edge of the sheet metal 3 , connected to a first lateral surface 22 and a second lateral surface 23 by means of two connecting radii R, as shown in the enlarged detai l of figure 3 ; furthermore , the third axial cavities 8 have a second surface 18 substantially parallel to a first surface 32 of the second axial cavities 7 , said first surface 32 being connected to a first lateral surface 42 and a second lateral surface 52 by means of at least one hollow sector 36 to form a protrusion; furthermore , the first surface 32 is connected to the first lateral surface 42 and to the second lateral surface 52 by means of two connecting radii R; preferably, the first surface 32 is connected to the first lateral surface 42 by means of the hollow sector 36 , furthermore the first lateral surface 42 and the second lateral surface 52 are parallel to each other .
Preferably, each of said first 6 and second 7 axial cavities comprises a second surface 34 connected to the first lateral surface 41 , 42 and to the second lateral surface 51 , 52 of said first 6 or second 7 inclined axial cavities by means o f at least one hollow sector 38 to form a protrusion .
Preferably, the rotor 1 comprises six magnetic poles 13 , 14 , each comprising three flow barriers
9 , 10 , 11 : an external flow barrier 11 , an intermediate flow barrier 10 and an internal flow barrier 9 . In particular, said flow barrier 9 , 10 , 11 comprises : a pair of axial cavities 6 , 7 inclined and arranged symmetrically with respect to a radius Rl , R2 of the lamination 3 passing through the centre C of rotation of the rotor 1 and suitable for hous ing a flow generator, preferably a permanent magnet . In this way, each flow barrier 9 ,
10 , 11 forms a figure similar to a "V" , whose inclined arms are formed by the pair of axial cavities 6 , 7 .
Preferably, the external flow barrier 11 comprises a pair of first axial cavities 6 inclined and arranged symmetrically with respect to a radius Rl , R2 of the lamination 3 passing through the centre C of rotation of the rotor 1 and suitable for hosting a flow generator, preferably a permanent magnet ; said pair of first axial cavities 6 forms a figure similar to a "V" , whose inclined arms are formed by the pair of f irst axial cavities 6 having their respective second surfaces 34 parallel to each other in the direction of the radius Rl , R2 of the lamination 3 .
Preferably, the intermediate flow barrier 10 and the internal flow barrier 9 comprise : a pair of second axial cavities 7 inclined and arranged symmetrically with respect to a radius Rl , R2 of the lamination 3 passing through the centre C of rotation of the rotor 1 and suitable for housing a flow generator, preferably a permanent magnet , and a pair of third axial cavities 8 inclined and arranged symmetrically with respect to said second axial cavities 7 .
In this way, each intermediate f low barrier 10 and internal flow barrier 9 forms a figure similar to a "V" , the inclined arms of which are formed by the pair of second axial cavities 7 and third axial cavities 8 , said second axial cavities 7 having their respective second surfaces 34 parallel to each other in the direction of the radius Rl , R2 of the lamination 3 .
Each flow barrier 9 , 10 , 11 corresponds to an opening angle 013 which defines the width of the "V" shape ( Fig . 4 ) .
These opening angles 013 are identi fied by two straight lines , each passing through the second lateral surfaces 51, 52 of the first 6 and second 7 inclined axial cavities of each flow barrier 9, 10, 11.
Preferably, the rotor 1 comprises three primary magnetic poles 13 and three secondary magnetic poles 14, each comprising three flow barriers 9, 10, 11. In particular, each of the three primary magnetic poles 13 preferably comprises an external flow barrier 11 whose opening angle 013 is substantially equal to 124°±10°, an intermediate flow barrier 10 whose opening angle 013 is substantially equal to 124°±10°, an internal flow barrier 9 whose opening angle 013 is substantially equal to 124°±10°; each of the three secondary magnetic poles 14 preferably comprises an external flow barrier 11 whose opening angle 013 is substantially equal to 124°±10°, an intermediate flow barrier 10 whose opening angle 013 is substantially equal to 124°±10°, an internal flow barrier 9 whose opening angle 013 is substantially equal to 124°±10°.
The amplitude of the three flow barriers 9, 10, 11 of each primary and secondary magnetic pole 13, 14 is defined by identifying the opening angles 01, 02, ..., 012, included between two straight lines projected from the theoretical centre C of rotation of the rotor 1 and each passing through a connection point R of the surfaces 31 and 12, substantially parallel to the edge of the sheet metal 3, of each first and third inclined axial cavity 6, 8, respectively with the first and second lateral surfaces 41, 51 of each first inclined axial cavity 6 and with the first and second lateral surfaces 22, 23 of each third inclined axial cavity 8.
In particular, for each flow barrier 9, 10,
11, an internal opening angle 01, 03, 05, 07, 09, 011 is identified, included between two straight lines projected from the centre C of rotation of the rotor 1 and passing through the connection point R of the surfaces 31, 12 substantially parallel to the edge of the sheet metal 3 of each first 6 and third 8 inclined axial cavity, respectively with the second lateral surface 51 of each first inclined axial cavity 6 and with the second lateral surface 23 of each third inclined axial cavity 8, and an external opening angle 02, 04, 06, 08, 010, 012 is also identified, included between two straight lines projected from the centre C of rotation of the rotor 1 and passing through the connection point R of the surfaces 31 , 12 substantially parallel to the edge of the sheet metal 3 of each first 6 and third 8 inclined axial cavity, respectively with the first lateral surface 41 of each first axial cavity 6 inclined and with the first lateral surface 22 of each third axial cavity 8 inclined .
The Table 1 below lists the values of the opening angles 01 , 02 , ..., 06 for three primary magnetic poles 13 and the values of the opening angles 07 , 08 , ..., 012 for three secondary magnetic poles 14 of the rotor 1 .
Table 1
In particular, the secondary magnetic poles 14 each comprise: an external flow barrier 11 whose external opening angle 08 is between 27° 83' and 31° 83', preferably substantially equal to 29° 83' ; an intermediate flow barrier 10 whose external opening angle 010 is between 42° 95' and 46° 95' , preferably substantially equal to 44° 95' ; an internal flow barrier 9 whose external opening angle 012 is between 57° 11' and 61° 11' , preferably substantially equal to 59° 11' ; the primary magnetic poles 13 each comprise: an external flow barrier 11 whose external opening angle 02 is between 23° 59' and 27° 59' , preferably substantially equal to 25° 59' ; an intermediate flow barrier 10 whose external opening angle 04 is between 34° 94' and 38° 94' , preferably substantially equal to 36° 94' ; an internal flow barrier 9 whose external opening angle 06 is between 49° 47' and 53° 47' , preferably substantially equal to 51° 47' .
Furthermore, the secondary magnetic poles 14 each comprise: an external flow barrier 11 whose internal opening angle 07 is between 21° 73' and 25° 73' , preferably substantially equal to 23° 73' ; an intermediate flow barrier 10 whose internal opening angle 09 is between 36° 55' and 40° 55' , preferably substantially equal to 38° 55' ; an internal flow barrier 9 whose internal opening angle 011 is between 50° 65' and 54° 65' , preferably substantially equal to 52° 65' ; the primary magnetic poles 13 each comprise: an external flow barrier 11 whose internal opening angle 01 is between 18° 16' and 22° 16' , preferably substantially equal to 20° 16' ; an intermediate flow barrier 10 whose internal opening angle 03 is between 28° 93' and 32° 93' , preferably substantially equal to 30° 93' ; an internal flow barrier 9 whose internal opening angle 05 is between 43° 86' and 47° 86' , preferably substantially equal to 45° 86' .
Preferably, the radii of connection R between the surface 12 substantially parallel to the edge of the lamination 3 and the first 22 or second lateral surface 23 of each inclined third axial cavity 8 are included within the range 0.2 - 1 mm. Preferably, the radii of connection R between the first surface 31 substantially parallel to the edge of the lamination 3 and the first 41 or second 51 lateral surface of each inclined first axial cavity 6 are included within the range 0.2 - 1 mm.
Preferably, the rotor 1 comprises primary magnetic poles 13 and secondary magnetic poles 14 arranged alternately with respect to each other. In this way the flow barriers 9, 10, 11 of two consecutive magnetic poles 13, 14 are asymmetrical to each other and this limits , compared to the electrical machines of the prior art , the torque ripple and the harmonics of counter-electromotive force .
It is however possible to have all the distance spectra that satis fy the values of the angles speci fied above .
In a known manner, an electric machine comprises a fixed part , the stator, and a moving part , the rotor, arranged coaxially one inside the other . Typically, the rotor is located inside the stator, which comprises electric coils capable of generating a magnetic field that allows the rotor to rotate .
The electric machine according to the invention also comprises the rotor 1 described above , and between the rotor 1 and the stator an air gap of thickness between 0 . 5 mm and 1 . 5 mm .
Advantageously, the rotor and the electric machine of the invention allow to obtain a better efficiency and better performance with a high "air gap" , which entails greater machining tolerances of the rotor and lower costs .
Another advantage of the present invention is to reduce the torque ripple and the harmonics of counter-electromotive force.

Claims

1. Rotor (1) for an electric machine comprising:
- a rotation shaft;
- a lamellar pack fixed on the rotation shaft and comprising a plurality of laminations (3) comprising three pairs of primary (13) and secondary (14) magnetic poles, each magnetic pole comprising an external flow barrier (11) , an intermediate flow barrier (10) and an internal flow barrier (9) , each flow barrier (9, 10, 11) comprising :
- a pair of first (6) or a pair of second (7) axial cavities suitable for housing a permanent magnet, inclined and arranged symmetrically with respect to a radius (Rl, R2 ) of the lamination (3) passing through the centre (C) of rotation of the rotor (1) , said first (6) axial cavities having a first surface (31) substantially parallel to the edge of the lamination (3) , connected with a first lateral surface (41) and a second lateral surface (51) ; said internal flow barrier (9) and said intermediate flow barrier (10) further comprising a pair of third (8) inclined axial cavities arranged symmetrically with respect to said second axial cavity (7) and having a first surface (12) substantially parallel to the edge of the sheet metal (3) , connected to a first lateral surface (22) and a second lateral surface (23) , said third (8) axial cavities having a second surface (18) substantially parallel to a first surface (32) of the second axial cavities (7) , said first surface (32) being connected to a first lateral surface (42) and to a second lateral surface (52) of the second axial cavities (7) ; the width of the three flow barriers (9, 10, 11) of each primary (13) and secondary (14) magnetic pole being defined by external opening angles (02, 04, 06, 08, 010, 012) , corresponding to the external limits of the three flow barriers (9, 10, 11) , included between two straight lines projected from the centre (C) of rotation of the rotor (1) and each passing through a connection point (R) of the surfaces (31, 12) substantially parallel to the edge of the sheet metal (3) of each first (6) and second (8) axial cavity inclined respectively with the first lateral surface (41) of each first axial cavity (6) inclined and with the first lateral surface (22) of each third axial cavity (8) inclined, wherein: said secondary magnetic poles (14) each comprise an external flow barrier (11) whose external opening angle (08) is between 27° 83' and 31° 83', an intermediate flow barrier (10) whose external opening angle (010) is between 42° 95' and 46° 95', an internal flow barrier (9) whose external opening angle (012) is between 57° 11' and 61° 11' ; and said primary magnetic poles (13) each comprise an external flow barrier (11) whose external opening angle (02) is between 23° 59' and 27° 59' , an intermediate flow barrier (10) whose external opening angle (04) is between 34° 94' and 38° 94' , an internal flow barrier (9) whose external opening angle (06) is between 49° 47' and 53° 47' , said primary magnetic poles (13) and said secondary magnetic poles (14) being arranged alternately with respect to each other.
2. Rotor (1) for an electric machine according to claim 1, characterised in that the amplitude of the three flow barriers (9, 10, 11) of each primary (13) and secondary (14) magnetic pole is defined by internal opening angles (01, 03, 05, 07, 09, 011) included between two straight lines projected from the centre (C) of rotation of the rotor (1) and each passing through a connection point (R) of the surfaces (31, 12) substantially parallel to the edge of the sheet metal (3) of each first (6) and third (8) axial cavity inclined respectively with the second lateral surface (51) of each first axial cavity (6) inclined and with the second lateral surface (23) of each third axial cavity (8) inclined, and characterised in that: said secondary magnetic poles (14) each comprise an external flow barrier (11) whose internal opening angle (07) is between 21° 73' and 25° 73', an intermediate flow barrier (10) whose internal opening angle (09) is between 36° 55' and 40° 55', an internal flow barrier (9) whose internal opening angle (011) is between 50° 65' and 54° 65' ; and said primary magnetic poles (13) each comprise an external flow barrier (11) whose internal opening angle (01) is between 18° 16' and 22° 16', an intermediate flow barrier (10) whose internal opening angle (03) is between 28° 93' and 32° 93', an internal flow barrier (9) whose internal opening angle (05) is between 43° 86' and 47° 86' .
3. Rotor (1) for an electric machine according to claim 1 or 2, characterised in that: said secondary magnetic poles (14) each comprise an external flow barrier (11) whose external opening angle (08) is substantially equal to 29° 83', an intermediate flow barrier (10) whose external opening angle (010) is substantially equal to 44° 95', an internal flow barrier (9) whose external opening angle (012) is substantially equal to 59° 11 ’ ; and said primary magnetic poles (13) each comprise an external flow barrier (11) whose external opening angle (02) is substantially equal to 25° 59' , an intermediate flow barrier (10) whose external opening angle (04) is substantially equal to 36° 94' , an internal flow barrier (9) whose external opening angle (06) is substantially equal to 51° 47' .
4. Rotor (1) for an electric machine according to any of the preceding claims, characterised in that: said secondary magnetic poles (14) each comprise an external flow barrier (11) whose internal opening angle (07) is substantially equal to 23° 73' , an intermediate flow barrier (10) whose internal opening angle (09) is substantially equal to 38° 55' , an internal flow barrier (9) whose internal opening angle (011) is substantially equal to 52° 65' ; and said primary magnetic poles (13) each comprise an external flow barrier (11) whose internal opening angle (01) is substantially equal to 20° 16' , an intermediate flow barrier (10) whose internal opening angle (03) is substantially equal to 30° 93' , an internal flow barrier (9) whose internal opening angle (05) is substantially equal to 45° 86' .
5. Rotor (1) for an electric machine according to any of the preceding claims, characterised in that the width of the three flow barriers (9, 10, 11) of each primary (13) and secondary (14) magnetic pole is defined by opening angles (013) identified by two straight lines each passing through the second lateral surfaces (51, 52) of the first (6) and second (7) inclined axial cavities of each flow barrier (9, 10, 11) , and characterised in that it comprises : three primary magnetic poles (13) , each comprising an external flow barrier (11) whose opening angle (013) is between 114° and 134°, an intermediate flow barrier (10) whose opening angle (013) is between 114° and 134°, an internal flow barrier (9) whose opening angle (013) is between 114° and 134°;
- three secondary magnetic poles (14) , each comprising an external flow barrier (11) whose opening angle (013) is between 114° and 134°, an intermediate flow barrier (10) whose opening angle (013) is between 114° and 134°, an internal flow barrier (9) whose opening angle (013) is between 114° and 134° .
6. Rotor (1) for an electric machine according to claim 5, characterised in that it comprises: three primary magnetic poles (13) , each comprising an external flow barrier (11) whose opening angle (013) is substantially equal to 124°, an intermediate flow barrier (10) whose opening angle (013) is substantially equal to 124°, an internal flow barrier (9) whose opening angle (013) is substantially equal to 124°;
- three secondary magnetic poles (14) , each comprising an external flow barrier (11) whose opening angle (013) is substantially equal to 124°, an intermediate flow barrier (10) whose opening angle (013) is substantially equal to 124°, an internal flow barrier (9) whose opening angle (013) is substantially equal to 124°.
7. Electric machine comprising a fixed part, the stator, and the rotor (1) according to any of the preceding claims arranged movably inside the stator, characterised in that it comprises, between the rotor (1) and the stator, an air gap of a thickness between 0.5 mm and 1.5 mm.
PCT/IT2025/050048 2024-03-13 2025-03-10 Rotor for electric machine and electric machine comprising such rotor Pending WO2025191619A1 (en)

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IT102024000005590 2024-03-13

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130147299A1 (en) 2011-12-09 2013-06-13 GM Global Technology Operations LLC Interior permanent magnet machine with pole-to-pole asymmetry of rotor slot placement
US20160365762A1 (en) 2015-06-09 2016-12-15 Ford Global Technologies, Llc Surface Groove Patterns for Permanent Magnet Machine Rotors
US10778054B2 (en) 2015-06-12 2020-09-15 Jaguar Land Rover Limited Electric drive motor
US20230198325A1 (en) 2020-09-25 2023-06-22 Daikin Industries, Ltd. Rotating machine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130147299A1 (en) 2011-12-09 2013-06-13 GM Global Technology Operations LLC Interior permanent magnet machine with pole-to-pole asymmetry of rotor slot placement
US20160365762A1 (en) 2015-06-09 2016-12-15 Ford Global Technologies, Llc Surface Groove Patterns for Permanent Magnet Machine Rotors
US10778054B2 (en) 2015-06-12 2020-09-15 Jaguar Land Rover Limited Electric drive motor
US20230198325A1 (en) 2020-09-25 2023-06-22 Daikin Industries, Ltd. Rotating machine

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