JP2008072790A - Rotor of ipm motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotor of an IPM motor in which breakage of a permanent magnet is prevented and irreversible demagnetization occurring in the permanent magnet is suppressed. <P>SOLUTION: In the rotor 14 of the IPM motor having the permanent magnet 16 inserted in a magnet insertion slot 14c formed in a yoke 14a, a metal plate 17 is disposed, in the magnet insertion slot 14c, outside in the radial direction of the rotor and the permanent magnet 16 is disposed inside in the radial direction of the rotor, making the surface area of the metal plate 17 inside in the radial direction of the rotor smaller than that of the permanent magnet outside in the radial direction of the rotor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotor of an IPM motor in which a magnet is embedded in a rotor.

For example, a driving motor is mounted on a vehicle such as a hybrid vehicle (see, for example, Patent Document 1).
By the way, there is an IPM (Interior Permanent Magnetic) motor in which a magnet is embedded in a rotor. In the rotor of this IPM motor, in order to prevent the permanent magnet from being damaged during rotation, There is a structure in which a metal plate is disposed outside and inserted into a magnet insertion slot of a yoke (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 10-285891 Japanese Patent Laid-Open No. 2005-20819

  By the way, permanent magnets tend to cause irreversible demagnetization due to the concentration of magnetic flux in a part during excitation, and irreversible to permanent magnets even in the case where a metal plate for preventing damage is disposed as described above. There was a problem that demagnetization was likely to occur.

  Therefore, an object of the present invention is to provide a rotor of an IPM motor that can prevent damage to the permanent magnet and suppress irreversible demagnetization that occurs in the permanent magnet.

  In order to achieve the above object, a first aspect of the invention relates to a permanent magnet (for example, in the embodiment) in a magnet insertion slot (for example, the magnet insertion slot 14c in the embodiment) formed in a yoke (for example, the yoke 14a in the embodiment). In a rotor (for example, the rotor 14 in the embodiment) of an IPM motor (for example, the IPM motor 10 in the embodiment) formed by inserting the permanent magnet 16), a metal plate (for example, in the embodiment) is disposed outside the magnet insertion slot in the rotor radial direction. And the permanent magnet is disposed on the inner side in the rotor radial direction, and the surface area on the inner side in the rotor radial direction of the metal plate is smaller than the surface area on the outer side in the rotor radial direction of the permanent magnet. .

  The invention according to claim 2 is the invention according to claim 1, wherein the metal plate is a space portion on the outer side in the rotor radial direction of the magnetic flux concentrating portion (for example, the edge portion 16a and the corner portion 16b in the embodiment) of the permanent magnet. (For example, the space portions 23 and 24 in the embodiment) are formed.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the metal plate is a space portion (for example, the space portion 23 in the embodiment) outside the rotor radial direction end of the permanent magnet in the rotor radial direction. It is characterized by forming.

  The invention according to a fourth aspect is the invention according to any one of the first to third aspects, wherein the metal plate is a space portion (for example, the space portion 24 in the embodiment) outside the corner portion of the permanent magnet in the rotor radial direction. ).

  According to a fifth aspect of the present invention, in the rotor of the IPM motor in which a permanent magnet is inserted into a magnet insertion slot formed in the yoke, a metal plate is disposed outside the rotor radial direction in the magnet insertion slot and the rotor diameter is increased. The permanent magnet is arranged on the inner side in the direction, and the metal plate includes an easily magnetic saturation type electromagnetic steel sheet (for example, the easy magnetic saturation type electromagnetic steel sheet 25 in the embodiment) and a hardly magnetic saturation type electromagnetic steel sheet (for example, the hardly magnetic saturation type in the embodiment). It is characterized by comprising an electromagnetic steel plate 26).

  According to the first aspect of the present invention, since the metal plate is disposed outside the rotor radial direction and the permanent magnet is disposed radially inside the magnet insertion slot formed in the yoke, the metal plate is interposed. This prevents the permanent magnet from contacting the inner surface of the magnet insertion slot during rotation. Therefore, damage to the permanent magnet can be prevented. In addition, since the surface area inside the rotor radial direction of the metal plate is smaller than the surface area outside the rotor radial direction of the permanent magnet, the non-contact portion of the metal plate is arranged at the magnetic flux concentration portion during excitation of the permanent magnet, thereby concentrating the magnetic flux. The amount of magnetic flux in the part can be relaxed, and the magnetic flux can be prevented from concentrating in part. Therefore, irreversible demagnetization occurring in the permanent magnet can be suppressed, and the demagnetization resistance can be improved.

  According to the second aspect of the present invention, the metal plate forms a space portion on the outer side in the rotor radial direction of the magnetic flux concentrating portion during excitation of the permanent magnet, so that the amount of magnetic flux in the magnetic flux concentrating portion can be reduced. It is possible to reliably suppress the magnetic flux from concentrating on the part. Therefore, irreversible demagnetization that occurs in the permanent magnet can be reliably suppressed, and the demagnetization resistance can be reliably improved.

  According to the invention which concerns on Claim 3, since a metal plate forms a space part in the rotor radial direction outer side of the edge part of the rotor circumferential direction which is a magnetic flux concentration part of a permanent magnet, the magnetic flux amount of a magnetic flux concentration part is relieve | moderated. It is possible to reliably suppress the magnetic flux from concentrating on a part. Therefore, irreversible demagnetization that occurs in the permanent magnet can be reliably suppressed, and the demagnetization resistance can be reliably improved.

  According to the invention of claim 4, since the metal plate forms a space portion on the outer side in the rotor radial direction of the corner portion that is the magnetic flux concentration portion of the permanent magnet, the magnetic flux amount of the magnetic flux concentration portion can be relaxed, It is possible to reliably suppress the magnetic flux from concentrating on a part. Therefore, irreversible demagnetization that occurs in the permanent magnet can be reliably suppressed, and the demagnetization resistance can be reliably improved.

  According to the fifth aspect of the present invention, since the metal plate is disposed on the outer side in the rotor radial direction and the permanent magnet is disposed on the inner side in the rotor radial direction in the magnet insertion slot formed in the yoke, the metal plate is interposed. This prevents the permanent magnet from contacting the inner surface of the magnet insertion slot during rotation. Therefore, damage to the permanent magnet can be prevented. In addition, since the metal plate is composed of an easily magnetic saturation type electromagnetic steel sheet and a hardly magnetic saturation type electromagnetic steel sheet, by arranging the easy magnetic saturation type electromagnetic steel sheet of the metal plate in the magnetic flux concentration part during excitation of the permanent magnet, the magnetic flux concentration The amount of magnetic flux in the part can be relaxed, and the magnetic flux can be prevented from concentrating in part. Therefore, irreversible demagnetization occurring in the permanent magnet can be suppressed, and the demagnetization resistance can be improved.

A rotor of an IPM motor according to an embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is an exploded perspective view showing a brushless IPM motor. In FIG. 1, the IPM motor 10 has a stator 12 and a rotor 14 of the present embodiment disposed inside the stator 12, and the rotor 14 includes a yoke 14 a and a permanent magnet 16 disposed in the yoke 14. And.

  A plurality of stator magnetic poles 12 a are projected from the inner periphery of the stator 12 toward the center of the stator 12. A coil (not shown) is fitted to each of the stator magnetic poles 12a. Three protrusions 12b are provided on the outer peripheral side of the stator 12, and bolts (not shown) are inserted into holes formed in the protrusions 12b and fixed to a housing (not shown).

  The yoke 14a of the rotor 14 is formed by laminating a number of silicon steel plates. The rotor 14 is provided with a plurality of rotor magnetic poles 14b protruding so as to face the stator magnetic pole 12a. A magnet insertion slot 14c is formed in each of the rotor magnetic poles 14b. A field permanent magnet 16 is disposed on the inner side in the rotor radial direction in the magnet insertion slot 14c, and a metal plate 17 is disposed on the outer side in the rotor radial direction. Has been.

  The brushless motor 10 having such a configuration is configured as a thin inner rotor type brushless motor as a whole, and a bolt fastening portion 18a (shown in FIG. 2) of the mounting surface 18 on the center side of the rotor 14 is a crankshaft of a vehicle engine. A bolt fastening portion 20a (shown in FIG. 2) of the mounting surface 20 on the outer peripheral side of the rotor 14 is bolted to a transmission (not shown), and is fastened to one end of the hybrid vehicle (not shown). Used as one of the driving sources.

  As shown in FIG. 3, the permanent magnet 16 has a rectangular shape in a plan view and a side view, and is generally formed in a plate shape. The permanent magnet 16 is configured by applying a rust-resistant plating 21 to the entire surface of a magnet body 16A manufactured by sintering rare earth metal, for example, neodymium, iron, boron, and the like. Further, a fixing film 22 is formed on the surface.

  4 and 5, the metal plate 17 accommodated in the magnet insertion slot 14c together with the permanent magnet 16 has a substantially rectangular shape in plan view and side view, and has the same strength as the yoke 14a. An electromagnetic steel sheet is manufactured by press forming.

  Here, the length of the metal plate 17 in the rotor axial direction is made equal to the length of the permanent magnet 16 in the rotor axial direction, and the width in the rotor circumferential direction is larger than the width of the permanent magnet 16 in the rotor circumferential direction. It has been made smaller. Furthermore, arc-shaped notches 17 a having the same size are formed at the four corners of the metal plate 17. Such a metal plate 17 is accommodated in the magnet insertion slot 14c in a state in which the center position in the rotor circumferential direction matches the permanent magnet 16 and the position in the rotor axial direction is matched.

  As a result, the surface area on the inner side in the rotor radial direction of the metal plate 17, that is, the area of the contact surface 17 b in contact with the permanent magnet 16 is made smaller than the surface area of the outer outer surface 16 c in the rotor radial direction of the permanent magnet 16. Further, the metal plate 17 exposes the end edge portion 16a having a predetermined width in the rotor circumferential direction of the permanent magnet 16 to the outer side in the rotor radial direction, and thus on the outer side in the rotor radial direction of the end edge portion 16a of the permanent magnet 16. A space 23 is formed. Further, the metal plate 17 exposes the corner portion 16b of the permanent magnet 16 to the outer side in the rotor radial direction by the notch portion 17a, so that the space portion 24 is formed on the outer side in the rotor radial direction of the corner portion 16b of the permanent magnet 16. Form. Here, the corner 16b of the permanent magnet 16 exposed in the space 24 is wider in the circumferential direction of the rotor than the edge 16a of the permanent magnet 16 exposed in the space 23. The edge 16a and the corner 16b of the permanent magnet 16 are the magnetic flux concentrating portions that emit the magnetic flux most during the excitation of the permanent magnet 16, and the metal plate 17 is the magnetic flux concentrating portion of the permanent magnet 16. The space portions 23 and 24 described above are formed on the outer side in the rotor radial direction of the end edge portion 16a and the corner portion 16b.

  According to the rotor 14 of the first embodiment described above, the metal plate 17 is disposed on the outer side in the rotor radial direction in the magnet insertion slot 14c formed on the yoke 14a made of laminated steel plates and is permanently on the inner side in the rotor radial direction. Since the magnet 16 is disposed, the permanent magnet 16 comes into contact with the laminated fracture surface step (see FIG. 3B) on the inner surface of the magnet insertion slot 14c on the outer side in the rotor radial direction when the metal plate 17 is interposed. Can be prevented. Therefore, damage to the permanent magnet 16 can be prevented. Further, since the permanent magnet 16 is in surface contact with the metal plate 17, no local load is applied to the rust-resistant plating 21 on the surface of the permanent magnet 16, and therefore, the low-strength rust-proof only with the rust-proof function. Can be used.

  Moreover, the metal plate 17 has a surface area on the inner side in the rotor radial direction that is smaller than a surface area on the outer side in the rotor radial direction of the permanent magnet 16, and is a portion that generates the magnetic flux most during excitation of the permanent magnet 16, that is, a magnetic flux concentrating portion. Since the space portions 23 and 24 are formed outside the end edge portion 16a and the corner portion 16b in the rotor radial direction, the amount of magnetic flux at the end edge portion 16a and the corner portion 16b, which are magnetic flux concentrating portions, can be reduced. It is possible to reliably suppress the magnetic flux from concentrating on the part. Therefore, the irreversible demagnetization generated in the permanent magnet 16 can be reliably suppressed, and the demagnetization resistance can be reliably improved.

  Furthermore, since the metal plate 17 has a substantially rectangular shape and is formed with the notches 17a at the corners, it can be easily formed by press molding.

  The embodiment described above can be modified as follows.

  By using an insulating steel sheet coated with insulation as the metal plate 17, insulation between the permanent magnet 16 and the cross section of the metal plate 17 is ensured, eddy current is reduced, and loss is reduced.

  As shown in FIG. 6, a metal plate 17 having the same size as the permanent magnet 16 is prepared in the rotor axial direction and the rotor circumferential direction, and the magnetically saturated magnetic steel sheet that easily magnetically saturates the portion corresponding to the space 23 described above. The remaining portion is formed of a hard magnetic saturation type magnetic steel sheet 26 which is hard to be magnetically saturated.

  As shown in FIG. 7A, the length of the metal plate 17 in the above embodiment in the circumferential direction of the rotor is increased by a predetermined amount, and a notch 17a is formed only on one side in the circumferential direction of the rotor. The space 23 and the space 24 are formed only on one side in the circumferential direction.

  As shown in FIG. 7B, a metal plate 17 having the same size as that of the permanent magnet 16 is prepared in the rotor axial direction and the rotor circumferential direction, and slits 28 are formed at the corners of the metal plate 17.

  As shown in FIG. 7C, a metal plate 17 having the same size as the permanent magnet 16 is prepared in the rotor axial direction and the rotor circumferential direction, and longitudinal slits 29 along the rotor axial direction are provided near both ends of the rotor circumferential direction. Form.

  As shown in FIG. 7 (d), a metal plate 17 having the same size as the permanent magnet 16 is prepared in the rotor axial direction and the rotor circumferential direction, and a key shape along two sides forming each vertex at each corner. The slit 30 is formed.

It is a disassembled perspective view of the principal part of the IPM motor to which the rotor of the IPM motor which concerns on one Embodiment of this invention was applied. It is a front view of the principal part of the IPM motor to which the rotor of the IPM motor which concerns on one Embodiment of this invention was applied. The principal part of the rotor of the IPM motor which concerns on one Embodiment of this invention is shown, (a) is a front view, (b) is AA sectional drawing of (a). It is a top view which shows the permanent magnet and metal plate of the rotor of the IPM motor which concern on one Embodiment of this invention. It is a disassembled perspective view which shows the permanent magnet and metal plate of the rotor of the IPM motor which concern on one Embodiment of this invention. It is a disassembled perspective view of the permanent magnet and metal plate which show the modification of the rotor of the IPM motor which concerns on one Embodiment of this invention. It is a top view of the permanent magnet and metal plate which show the modification of the rotor of the IPM motor which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 IPM motor 14 Rotor 14a Yoke 14c Magnet insertion slot 16 Permanent magnet 16a End edge part (magnetic flux concentration part)
16b Corner part (magnetic flux concentration part)
17 Metal Plates 23, 24 Space 25 Easy Magnetic Saturation Type Electrical Steel Sheet 26 Hard Magnetic Saturation Type Electrical Steel Sheet

Claims (5)

In a rotor of an IPM motor in which a permanent magnet is inserted into a magnet insertion slot formed in a yoke,
In the magnet insertion slot, a metal plate is arranged on the rotor radial direction outer side and the permanent magnet is arranged on the rotor radial direction inner side,
The rotor of an IPM motor, wherein a surface area of the metal plate in the rotor radial direction inner side is smaller than a surface area of the permanent magnet in the rotor radial direction outer side. 2. The rotor of an IPM motor according to claim 1, wherein the metal plate forms a space portion on the outer side in the rotor radial direction of the magnetic flux concentration portion of the permanent magnet. 3. The rotor of an IPM motor according to claim 1, wherein the metal plate forms a space portion on the outer side in the rotor radial direction of the end portion of the permanent magnet in the circumferential direction of the rotor. The rotor of the IPM motor according to any one of claims 1 to 3, wherein the metal plate forms a space portion on an outer side in a rotor radial direction of a corner portion of the permanent magnet. In a rotor of an IPM motor in which a permanent magnet is inserted into a magnet insertion slot formed in a yoke,
In the magnet insertion slot, a metal plate is arranged on the rotor radial direction outer side and the permanent magnet is arranged on the rotor radial direction inner side,
The rotor of an IPM motor, wherein the metal plate is composed of an easily magnetic saturation type electromagnetic steel sheet and a hardly magnetic saturation type electromagnetic steel sheet.

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