ROTOR FOR PERMANENT MAGNET ELECTRICAL MACHINE

Abstract

A rotor for a permanent magnet electrical machine that includes a rotor house having a rotor house yoke, the rotor house yoke including for each of plural permanent magnet units, a magnet unit contact face and at least one through hole, at least one permanent magnet unit having a rotor house contact face, a fixing material portion between the magnet unit contact face of the rotor house yoke and the rotor house contact face of the magnet unit for fixing the magnet unit to the rotor house.

Claims

1. A rotor for a permanent magnet electrical machine, comprising: a rotor house having a rotor house yoke, the rotor house yoke comprising for each of a plurality of permanent magnet units, a magnet unit contact face and at least one through hole; at least one permanent magnet unit of the plurality of permanent magnet units having a rotor house contact face; and a fixing material portion between the magnet unit contact face of the rotor house yoke and the rotor house contact face of the at least one permanent magnet unit for fixing the at least one permanent magnet unit to the rotor house.

2. The rotor according to claim 1, wherein: the through hole enables injection of fixing material from a rotor house yoke side opposite to a side where the magnet unit contact face is located, and/or the at least one through hole is axially and circumferentially positioned within the magnet unit contact face, and/or the at least one through hole is delimited by an edge of the magnet unit contact face.

3. The rotor according to claim 1, wherein the at least one through hole has a circular cross-sectional shape, having constant cross-sectional diameter, and the at least one through hole is threaded.

4. The rotor according to claim 1, wherein an area size of an area extending axially and circumferentially of the fixing material portion is between 0.8 and 1.0 of an area size of an area extending axially and circumferentially of the rotor house contact face of the at least one permanent magnet unit, further wherein the fixing material portion is continuous and/or a thickness of the fixing material hole portion is between 0.05 mm and 0.3 mm.

5. The rotor according to claim 1, wherein the magnet unit contact face of the rotor house yoke and the rotor house contact face of the at least one permanent magnet unit are substantially flat, the fixing material portion forming a layer therebetween.

6. The rotor according to claim 1, wherein the rotor house has for each permanent magnet unit two positioning members integrally formed with the rotor house yoke, positioned at predetermined circumferential positions and/or extending in an axial direction and/or being parallel to each other and/or being arranged circumferentially adjacent to the at least one permanent magnet unit and/or contacting at and/or engaging with axially extending edges of the at least one permanent magnet unit at circumferential ends of the at least one permanent magnet unit.

7. The rotor according to claim 6, wherein the two positioning members are formed as guiding and/or engagement rails, being T-shaped and holding the at least one permanent magnet unit in the circumferential and radial direction at predetermined positions, and/or wherein the through hole is arranged circumferentially between the two positioning members at a circumferentially central position.

8. The rotor according to claim 1, wherein a number and/or axial position of the at least one through hole is chosen such that: an axial distance between the through hole and an axial end of the at least one permanent magnet unit is between 0.8 and 1.2 times a circumferential distance between the through hole and at least one circumferential edge of the at least one permanent magnet unit or a positioning member.

9. The rotor according to claim 1, wherein the fixing material comprises at least one of: a glue, a resin, a two-component adhesive, a thermosetting material, a thermoplastic material, an elastomer or elastic material, a two-part methacrylate adhesive, a Silane-modified polymer, providing an elastic bonding, wherein the fixing material having a viscosity between 35,000 and 120,000 cP, before applied to the rotor house contact face and the magnet unit contact face, the fixing material being allowed to cure after application.

10. The rotor according to claim 1, wherein a stator exposed surface of the at least one permanent magnet unit is at least partially curved, at axial ends, and/or wherein the at least one permanent magnet unit comprises: a base plate that is flat and comprised of carbon steel; a permanent magnet comprising NdFeB, mounted on the base plate; and a cover above the permanent magnet, welded at edges to the base plate and/or glued at the permanent magnet, comprising X2CrNiMo17-12-2.

11. The rotor according to claim 1, wherein the rotor house yoke forms a ring spanning a whole circumference and having a diameter between 5 m and 15 m and/or having axial extent between 2 m and 5 m, the ring having a symmetry axis along an axial direction, the circumference extending in a circumferential direction, a radial direction being perpendicular to the axial direction and the circumferential direction.

12. A permanent magnet electrical machine, comprising: a stator, having coils wound in a plurality of slots having concentrated winding topology, for providing a plurality of poles; and the rotor according to claim 1, wherein a number of poles is equal to a number of slots.

13. A wind turbine, comprising the permanent magnet electrical machine operable as a generator, according to claim 12.

14. A method of manufacturing a rotor for a permanent magnet electrical machine, the method comprising: machining, at a rotor house yoke of a rotor house, for each of a plurality of permanent magnet units, a magnet unit contact face and at least one through hole; arranging a rotor house contact face of at least one permanent magnet unit at the magnet unit contact face; injecting fixing material through the through hole, to form a fixing material portion between the magnet unit contact face of the rotor house and the rotor house contact face of the magnet unit for fixing the at least one permanent magnet unit to the rotor house.

15. The method according to claim 14, wherein providing the fixing material through the through hole comprises: applying pressure to the fixing material, to inject the fixing material through the through hole, in order to distribute the fixing material between the rotor house contact face of a magnet unit and the magnet unit contact face of the rotor house; wherein during injecting the fixing material has a viscosity between 35,000 and 120,000 cP, the method further comprising: solidifying the fixing material by applying heat and/or pressure.

Description

BRIEF DESCRIPTION

[0055] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0056] FIG. 1 schematically illustrates a portion of a rotor for a permanent magnet electrical machine according to an embodiment of the present invention in a perspective view;

[0057] FIG. 2 schematically illustrates a cross-sectional view of the portion of the rotor illustrated in FIG. 1;

[0058] FIG. 3 schematically illustrates in a perspective view a portion of a rotor house as used for a rotor according to an embodiment of the present invention;

[0059] FIG. 4 schematically illustrates a three-dimensionally partially cut-away view of a portion of a rotor according to an embodiment of the present invention;

[0060] FIG. 5 schematically illustrates another three-dimensionally partially cut-away view of a portion of a rotor according to an embodiment of the present invention;

[0061] FIG. 6 schematically illustrates an partially transparent elevational view of a portion of a rotor according to an embodiment of the present invention; and

[0062] FIG. 7 schematically illustrates a cross-sectional view of a magnet unit as employed in a rotor according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0063] The illustration in the drawings is in schematic form. It is noted that in different figures, elements similar or identical in structure and/or function are provided with the same reference signs or with reference signs, which differ only within the first digit. A description of an element not described in one embodiment may be taken from a description of this element with respect to another embodiment.

[0064] FIG. 1 schematically illustrates a perspective view of a portion of a rotor 1 for a permanent magnet electrical machine according to an embodiment of the present invention. The rotor 1 comprises a (portion of a) rotor house 3 having a rotor house yoke 5, the rotor house yoke 5 comprising for each of plural magnet units 7 a magnet unit contact face 9 (for example illustrated in FIG. 3) and at least one through hole 11.

[0065] The portion of the rotor 1 further comprises one permanent magnet unit 7 having a rotor house contact face 13 (for example illustrated in FIG. 2). The portion of the rotor 1 further comprises a fixing material portion 15 comprising a fixing material, in particular resin, glue or adhesive, between the magnet unit contact face 9 of the rotor house 3 and the rotor house contact face 13 of the magnet unit 7 for fixing the magnet unit 7 to the rotor house 3.

[0066] In FIG. 1, reference sign 16 indicates a circumferential direction, reference sign 17 indicates an axial direction and reference sign 18 indicates a radial direction.

[0067] FIG. 2 illustrates a cross-sectional view taken along the axial direction 17 of the portion of the rotor 1. As can be seen in FIG. 2, the magnet unit contact face 9 is arranged opposite to and close to the rotor house contact face 13 of the permanent magnet unit 7, wherein between these two faces, the fixing material portion 15 is arranged thereby fixing the magnet unit 7 to the rotor house yoke 5.

[0068] FIG. 3 illustrates in a perspective view a portion of a rotor house 3 as comprised in the rotor 1 of which a part is illustrated in FIG. 1. The entire rotor 1 may span a whole circumference in the circumferential direction 16 as illustrated in FIG. 1. As can be taken from FIG. 3, the magnet unit contact face 9 of the rotor house 3 is flat. The same holds for the rotor house contact face 13 of the permanent magnet unit 7.

[0069] As can be seen in FIGS. 1, 2, 3, the rotor house 3 has for each magnet unit 7 two positioning members 21, 23 which are, in the illustrated embodiment, integrally formed with the rotor house yoke 5. Further, the two positioning members 21, 23 are positioned at predetermined circumferential positions cl, c2 and extend in the axial direction 17. Further, the two positioning members 21, 23 are parallel to each other and are arranged circumferentially adjacent to the magnet unit 7.

[0070] In particular, the positioning members 21, 23 are formed as engagement rails which are T-shaped and hold the magnet unit 7 in a circumferential direction 17 and in a radial direction 18 at predetermined positions, cl, c2 and a predetermined radial position.

[0071] As can be appreciated from FIG. 3, the through hole 11 is arranged circumferentially between the positioning members 21, 23 at a circumferentially central position. As can also be appreciated from FIG. 3, the through hole 11 is axially and circumferentially positioned within the magnet unit contact face 9 and is delimited by an edge 12 of the magnet unit contact face 9. The through hole 11 is a circular cross-sectional shape through hole. The through hole 11 extends to the entire thickness of the rotor house yoke 5.

[0072] The through hole 11, 14 enables injection of fixing material from a rotor house yoke side 2 opposite to a side where the magnet unit contact face 9 is located

[0073] Depending on the size of the magnet unit 7, in particular lateral size as the size along the axial direction 17 and the circumferential direction 16, more than one through hole may be provided within the magnet unit contact face 9. In the embodiment as illustrated in FIG. 3, for example two through holes 11 and 14 are provided through which fixing material may be injected (in FIG. 3 from below). The dashed lines 24, 25 indicated in FIG. 3 indicate positions of axial edges 26, 27 of the magnet unit 7. The axial distance ad between the through hole 11 and the axial end 25 of the magnet unit 7 is thereby between 0.8 and 1.2 times a circumferential distance cd between the through hole 11 and at least one circumferential edge 28 or 29 of the magnet unit 7. In the illustrated example, also the circumferential distance cd may be defined as the circumferential distance between the through hole 11 and the circumferential position cl, c2 of one of the positioning members 21, 23.

[0074] The magnet unit 7 has a stator exposed surface 30 which is at least partially curved, for providing an advantageous focusing effect of the magnetic field.

[0075] FIG. 4 illustrates a partially cut-away three-dimensional view of a portion of a rotor 1 according to an embodiment of the present invention. It can be seen, that the through holes 11, 14 have a circular cross-sectional shape and have a constant diameter and shape along the thickness direction of the rotor house yoke 5 of the rotor house 3.

[0076] FIG. 5 illustrates another partially cut-away three-dimensional view of the portion of the rotor 1 as illustrated in FIG. 1.

[0077] FIG. 6 schematically illustrates in an elevational view a portion of a rotor 1 according to an embodiment of the present invention. Herein, FIG. 6 is an illustration in a partial transparent manner for illustrating the fixing material portion 15 which is arranged between the rotor house contact face 13 of the permanent magnet unit and the magnet unit contact face 9 of the rotor house yoke. The fixing material portion 15 has been applied between those two faces by injecting fixing material through one or both of the through holes 14, 11 provided in the rotor house yoke 5. As can be seen in FIG. 6, the fixing material portion 15 substantially is provided by two continuously filled circular (ring or disc) structures which therefore provide a continuous fixing material for reliable fixation.

[0078] A permanent magnet electrical machine further comprises a stator relative to which the rotor 1 is rotatably supported. Between stator coils and the permanent magnets 7, a gap is provided. Upon rotation of the rotor 1, the permanent magnets induce electric voltages in the windings of the stator. Due to the fixation employing the fixing material portion 15, the permanent magnets are fixedly connected to the rotor house 3 even during operation, i.e. rotation of the rotor 1 relative to the stator at high rotational speed.

[0079] The portion of the rotor 1 illustrated in FIGS. 1, 2, 4, 5, 6 (or portions thereof) may be manufactured using a method of manufacturing a rotor for the permanent magnet electrical machine according to an embodiment of the present invention. Thereby, a rotor house yoke of a rotor house may be provided and for each of plural permanent magnet units, a magnet unit contact face and at least one through hole may be provided, such as by machining and/or drilling and/or milling and/or boring.

[0080] Then, one or more magnet units 7 may be arranged at the respective magnet unit contact faces of the rotor house yoke. Thereby, for example, magnet units 7 may subsequently be inserted between the positioning members 21, 23 and may be moved to the respective intended axial position along the axial direction 17.

[0081] Then (i.e. after correct positioning the magnet units of the rotor house yoke), fixing material may be provided in particular by injecting, through the through hole to form the fixing material portion 15 between the magnet unit contact face of the rotor house and the rotor house contact face of the magnet unit for fixing the magnet unit 7 to the rotor house 3.

[0082] FIG. 7 illustrates in a schematic manner a cross-sectional view of a magnet unit 7 as may be employed for a rotor 1 according to an embodiment of the present invention. The magnet unit 7 comprises a base plate 31 which is in particular flat. At the base plate is mounted (e.g. using glue) a permanent magnet 32. The magnet 32 is covered by a cover 33 which may in particular be glued onto the permanent magnet 32. At edges 34, the cover 33 may be welded to the base plate 31. The base plate 31 comprises circumferentially protruding edges 35 or protrusions 35 which engage below the T-shaped guiding or positioning members 21, 23 for providing circumferential as well as radial support or fixation.

[0083] The gluing process enabled or provided by embodiments of the present invention allows to continue to use the cold-marriage technology and to insert the hot magnets after the stator is inserted into the rotor. That means, that the arrangement of the plural magnet units 7 may be formed after the stator has been assembled with the rotor house then being devoid of any permanent magnet units. Once all the magnet units 7 are inserted and the stator/rotor is aligned, the magnets may be injection-glued from outside and thereby the magnet units may be fixed to the rotor house.

[0084] The stator may for example be a 12 segment stator comprising 12 physically separate entities which may be mounted together by mounting or fixation means. The stator may comprise a concentrated winding topology.

[0085] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0086] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.