Rotating electric machine rotor
Patent Information
- Application Number
- FR2021001695
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2021-02-22
- Publication Date
- 2025-02-21
- Estimated Expiration
- 2041-02-22
Smart Images
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Abstract
Description
Title of the invention: Rotor of a rotating electrical machine Technical field
[0001] The present invention relates to rotating electrical machines, whether motors or generators, and more particularly to the rotors of such machines. The invention relates to rotors with permanent magnets.
[0002] The invention relates more particularly to synchronous or asynchronous alternating current machines. It relates in particular to traction or propulsion machines for electric (Battery Electric Vehicle) and / or hybrid (Hybrid Electric Vehicle - Plug-in Hybrid Electric Vehicle) motor vehicles, such as individual cars, vans, trucks or buses. The invention also applies to rotating electrical machines for industrial and / or energy production applications, in particular naval, aeronautical or wind power applications. Prior art
[0003] Permanent magnet rotors are generally composed of a rotor mass and permanent magnets of various geometric shapes. The rotor mass may comprise a stack of cut thin magnetic sheets. It may comprise one or more packets of sheets stacked on top of each other.
[0004] The permanent magnets can be arranged on the surface, directly facing the air gap or, as a variant, be arranged inside the rotor mass, in housings of the latter, then being called "buried" or "embedded".
[0005] In this case, they can be arranged in a row, as for example in application US 2007 / 0096578, in which the magnet housings have semi-circular rounded ends, as well as in application US 2007 / 0096577.
[0006] In applications CN110212666, US 2013 / 0020889 and CN 206650521, there is a permanent magnet arranged on the surface and a single row of buried magnets.
[0007] In applications US 2008 / 007131, WO 2019 / 179864 and KR 10-2018229, the permanent magnets of the two rows are arranged in a V.
[0008] In application WO 2019 / 174323, the rows are arranged such that two adjacent magnets of two consecutive poles are parallel to each other and two magnets of two rows are also parallel to each other.
[0009] There is a need to improve the magnetic performance and in particular the volume torque of rotating electrical machines, and to reduce their manufacturing and assembly costs. Summary of the invention
[0010] The invention aims to meet this need and thus has as its object, according to one of its aspects, a rotor of a rotating electrical machine, a rotor mass comprising sheets stacked on top of each other, the rotor mass comprising a plurality of housings, at least some of the housings, or even all of the housings, receiving one or more permanent magnets defining poles of the rotor, the housings of a pole being arranged in at least a first and a second row of housings, the first row of housing comprising three housings arranged in a U-shape, with a central housing and two lateral housings, a length of a largest rectangle inscribed in the central housing being equal to + / - 20% of the length of the largest rectangle inscribed in a lateral housing, at least one of the lateral housings, in particular the two lateral housings of the first row, comprising a recess which extends from the lateral housing towards the central housing.
[0011] Advantageously, the presence of two rows of housings makes it possible to increase the number of magnets received in the rotor mass, and thus to increase the resulting power density. It is thus possible to obtain more torque with the same rotor size. The invention advantageously makes it possible to improve the reluctant torque of the machine. Statement of the invention
[0012] 'Length' is measured along the axis of the row of housings. 'Width' is the dimension perpendicular to the length in the plane of a cross-section of the rotor mass.
[0013] The length of the largest rectangle inscribed in the central housing may be equal to + / - 20% of the length of the largest rectangle inscribed in a lateral housing, or even to + / - 17%, better still to + / - 15%, or even to + / - 10%, even better still to + / - 7%, or even to + / - 5%. In this ratio, the length of the largest rectangle inscribed in a lateral housing is taken as a reference.
[0014] In one embodiment, the length of a magnet in the second row may be equal to the length of a magnet in the first row. All magnets in a pole may have the same length.
[0015] In one embodiment, the rotor comprises a first and a second row of housings per pole, being devoid of an additional row.
[0016] The second row may be closer to the air gap than the first row. The first row is further from the air gap than the second row.
[0017] The first row may comprise a central housing and two lateral housings. The two lateral housings are symmetrical to each other with respect to an axis of the pole.
[0018] The rotor mass may comprise one or more stacks of laminations stacked on top of each other. Each stack of laminations may comprise at least one housing receiving the permanent magnet. In the case where the rotor mass comprises several stacks of laminations stacked on top of each other, the rotor mass may comprise, for a housing, one or more permanent magnets, for example one permanent magnet per stack of laminations.
[0019] The width of the largest rectangle inscribed in the central housing may be equal to + / - 50% of the width of the largest rectangle inscribed in a lateral housing, better still to 40%, even better still to 30%, or even to + / - 20%, better still to + / - 15%, or even to + / - 10%, even better still to + / - 7%, or even to + / - 5%. In this ratio, the width of the largest rectangle inscribed in a lateral housing is taken as a reference.
[0020] The width B of the central housing may be equal to the width B of a lateral housing.
[0021] The width A of a housing of the second row may be less than the width B of a housing of the first row. A ratio (BA) / B can be between 0 and 40%, better between 5 and 35%, or even between 10 and 30%, being for example of the order of 25%. In one embodiment, the width B of a housing of the first row can be equal to 3.7 mm and the width A of a housing of the second row can be equal to 2.8 mm.
[0022] In one embodiment, the width A of a housing of the second row may be equal to the width B of a housing of the first row. All the housings of a pole may have the same width A.
[0023] The number of permanent magnet sizes required can advantageously be reduced to two or three at most, or even to only one.
[0024] The side housings of the first row may be provided with permanent magnets. The permanent magnets of the side housings of the first row may be identical to each other. In particular, they may have the same cross-sectional size.
[0025] The central housing of the first row may be provided with one or more permanent magnets, or alternatively be devoid of them. Depending on the choice of the presence or absence of a central permanent magnet, the rotor may advantageously allow a certain modularity for the resulting machine.
[0026] The central housing of the first row may be provided with a permanent magnet of the same size as the permanent magnets of the side housings.
[0027] Alternatively, the central housing of the first row may be provided with a permanent magnet smaller than the permanent magnets of the side housings. This is advantageous from an electromagnetic point of view. Indeed, the permanent magnet being smaller than the housing, there is a part of the housing which is empty on the sides of the magnet, which empty part makes it possible to reduce electromagnetic leaks. genetics.
[0028] In another embodiment, the central housing of the first row is empty.
[0029] The housings of the second row may be arranged in a V. The second row may in particular comprise two housings arranged in a V. They may be symmetrical to each other with respect to an axis of the pole. In one embodiment, all the housings of the second row are provided with permanent magnets. The V-shaped configuration of the second row allows space to be saved and any risk of saturation of the magnetic circuit to be avoided.
[0030] In another embodiment, the housings of the second row are empty, being devoid of magnets.
[0031] The permanent magnets of the second row may be identical to each other. In particular, they may have the same cross-sectional size. The permanent magnets of the second row may have a different size from the permanent magnets of the first row, for example being smaller.
[0032] An angular opening a3 of the second row may be greater than or equal to twice the sum of the angular opening al between two consecutive poles and the angular opening a2 between the first and second rows. We can write a3 > 2 (al + a2). The angular openings are measured at the surface of the rotor, at the air gap, for a given pole of the rotor.
[0033] An angular opening a3 of the second row can be given by the following relation: a3 = k 2ir / (2p), where p is the number of rotor pole pairs and k is the polar opening coefficient, with the polar opening coefficient k being in the interval [22.5%; 37.5%], better in the interval [25%; 35%].
[0034] The choice of the value of the polar opening coefficient k makes it possible to optimize the resulting torque. In an exemplary embodiment, k is equal to 34.6%.
[0035] An angle a4 between the adjacent housings of two consecutive poles may be strictly greater than 0, being in particular between 5° and 35°, better between 12° and 30°, being for example 24.8° in one embodiment. A strictly positive angle a4 makes it possible to increase the salience torque. The choice of the value of the angle a4 makes it possible to improve the resulting torque.
[0036] The angle a4 may in particular be less than 55°, better still less than 50°, better still less than 40°, being in particular less than 35°. The two adjacent housings considered for the measurement of the angle a4 between the two consecutive poles are housings of the first row.
[0037] The recess may be configured to protrude radially from the central housing. The recess may protrude radially from the central housing by a distance Y of between 0 mm and twice the width of the central housing. This overhang can increase the magnetic flux path, which reduces flux leakage.
[0038] A width X of the recess may be between 0 mm and twice the width B of the central housing. The length Z of the recess may be between once the width B of the central housing and twice the latter.
[0039] These dimensions determine the size of the material bridge between the lateral housings and the central housing. This material bridge has a minimum width determined by the mechanical strength constraints. Its width is substantially equal to at least the thickness of the magnetic sheet.
[0040] A radial dimension W between the bottom of the second row and the first row can be between one time the width B of the central housing and three times the latter.
[0041] The recess may have an edge that extends at least partially parallel to an edge of the central housing.
[0042] At least one housing may comprise at least one stop for holding the permanent magnet intended to be received in the housing. Each housing may comprise a stop located towards the air gap.
[0043] The housings are each separated from the air gap by a bridge of material whose width is determined by the mechanical strength constraints. Their width is substantially equal to at least the thickness of the magnetic sheet. The length of these bridges is substantially equal to the width of the housings.
[0044] The lateral housings may also include a stop located towards the recess, for holding the permanent magnet.
[0045] The rotor may be devoid of circulation of cooling fluid in the housings. In particular, the recesses are not configured to allow the circulation of a cooling fluid.
[0046] The invention also relates to a rotating electrical machine comprising a stator and a rotor as defined above.
[0047] The machine can be used as a motor or as a generator. The machine can be reluctance. It can constitute a synchronous motor or, alternatively, a synchronous generator. Alternatively, it constitutes an asynchronous machine.
[0048] The maximum rotational speed of the machine may be high, for example greater than 10,000 rpm, better still greater than 12,000 rpm, for example of the order of 14,000 rpm to 15,000 rpm, or even 20,000 rpm or 24,000 rpm or 25,000 rpm. The maximum rotational speed of the machine may be less than 100,000 rpm, or even 60,000 rpm, or even less than 40,000 rpm, better still less than 30,000 rpm.
[0049] The invention may be particularly suitable for high-power machines.
[0050] The machine may comprise a single inner rotor or, alternatively, an inner rotor and an outer rotor, arranged radially on either side of the stator and coupled in rotation.
[0051] The machine can operate alone or be coupled to a gearbox. In this case, it is inserted into a housing which also houses a gearbox.
[0052] The machine comprises a stator. The latter comprises teeth defining notches between them. The stator may comprise electrical conductors, at least a portion of the electrical conductors, or even a majority of the electrical conductors, being able to be in the shape of a U-shaped or I-shaped pin. Alternatively, the electrical conductors may comprise round wire.
[0053] The stator can be connected in star or delta.
[0054] The machine may have a number of poles between 2 and 48, better between 4 and 24, or even between 6 and 12, for example being 6 or 8.
[0055] The invention also relates to a method of manufacturing a rotor of a rotating electrical machine as defined above.
[0056] The method may comprise the step of longitudinally introducing, along the axis of rotation of the rotor, at least one permanent magnet into the housing.
[0057] In the case where the rotor mass comprises several stacks of laminations stacked on top of each other, the method may firstly comprise the step of longitudinally introducing at least one permanent magnet into the housing of each stack of laminations, then the step of stacking the stacks of laminations on top of each other, with the permanent magnets in the housings. Brief description of the drawings
[0058] [Fig.l] [Fig.l] is a schematic and partial view, in cross-section, of a rotor of a rotating electrical machine according to the invention,
[0059] [Fig.2] [Fig.2] is a view similar to [Fig.l] without the permanent magnets,
[0060] [Fig.3] [Fig.3] is a view similar to [Fig.l],
[0061] [Fig.4a] [Fig.4a] is a view similar to [Fig.2] of an alternative embodiment,
[0062] [Fig.4b] [Fig.4b] is a view similar to [Fig.2] of an alternative embodiment,
[0063] [Fig.4c] [Fig.4c] is a view similar to [Fig.2] of an alternative embodiment,
[0064] [Fig.4d] [Fig.4d] is a view similar to [Fig.2] of an alternative embodiment,
[0065] [Fig.5] [Fig.5] is a view similar to [Fig.l] of an alternative embodiment,
[0066] [Fig.6] [Fig.6] is a view similar to [Fig.l] of an alternative embodiment.
[0067] [Fig.7a] [Fig.7a] is a view similar to [Fig.l] of an alternative embodiment.
[0068] [Fig.7b] [Fig.7b] is a view similar to [Fig.l] of another sheet of the variant of [Fig.7a]. Detailed description
[0069] Figures 1 to 3 illustrate a rotor 30 of a rotating electrical machine according to the invention, comprising a rotor mass 33 in which housings 10 are provided. Permanent magnets are inserted into each of the housings 10, so as to define poles of the rotor. This rotor is intended to be associated with a stator not shown.
[0070] In this example, the magnets are generally rectangular in cross-section as illustrated in the embodiments of FIGS. 1, 5 and 6. Each magnet has, in cross-section, on the one hand, a first large side and a second large side, opposite the first, and on the other hand, a first small side and a second small side, opposite the first. Each housing 10 is delimited by two faces facing respectively the first large side and the second large side of the magnet.
[0071] The housings 10 of a pole are arranged in a first row 11 of housings further from the air gap and a second row 12 of housings closer to the air gap.
[0072] The first row 11 of housings 10 comprises three housings 10 arranged in a U, with a central housing and two lateral housings symmetrical to each other with respect to an axis of the pole P.
[0073] A length L2 of a larger rectangle inscribed in the central housing is in the example described equal to the length L1 of the larger rectangle inscribed in a lateral housing. The 'length' is measured along the axis of the row of housings. The length L3 is designated as the length of a larger rectangle inscribed in a housing of the second row.
[0074] The width B of the largest rectangle inscribed in the central housing is equal to the width B of the largest rectangle inscribed in a lateral housing. We speak of 'width' to designate the dimension perpendicular to the length in the plane of a cross-section of the rotor mass.
[0075] The lateral housings of the first row 11 are provided with permanent magnets, as is the central housing. The permanent magnets of the lateral housings and the central housing of the first row 11 are identical to each other. In particular, they have the same cross-sectional size.
[0076] Furthermore, the two lateral housings of the first row 11 comprise a recess 15 which extends from the lateral housing towards the central housing. The recess 15 is configured to protrude radially from the central housing by a distance Y. The recess 15 has a width X and a length Z.
[0077] Further, the recess 15 has an edge that extends at least partially parallel to an edge of the central housing.
[0078] The second row 12 comprises two housings arranged in a V. They are symmetrical to each other with respect to an axis of the pole P. In the example described, all the housings of the second row 12 are provided with permanent magnets. The permanent magnets of the second row are identical to each other. In particular, they have the same cross-sectional size. On the other hand, the permanent magnets of the second row have a different size from the permanent magnets of the first row, being smaller. The width A of a housing of the second row is less than the width B of a housing of the first row.
[0079] A radial dimension W between the bottom of the second row and the first row can be between one time the width B of the central housing and three times the latter.
[0080] The lateral housings of the first row 11 as well as the housings of the second row 12 comprise at least one stop 16 for holding the permanent magnet intended to be received in the housing, this stop 16 being located towards the air gap.
[0081] We define the angular opening a3 of the second row 12. This angular opening a3 is greater than twice the sum of the angular opening al between two consecutive poles and the angular opening a2 between the first and second rows. We can write a3 > 2 (al + a2). In the example described, we have a3 = 1.2 * 2 (al + a2). The angular openings are measured at the surface of the rotor, at the air gap, for a given pole of the rotor, as illustrated in [Fig.2].
[0082] Furthermore, the angular opening a3 of the second row can be defined by the following relation: a3 = k 2ir / (2p), where p is the number of pairs of poles of the rotor which is in the example described 4, and k the polar opening coefficient, which is equal to 34.6%.
[0083] An angle a4 between the adjacent housings 10 of two consecutive poles is in the example described 24.8°. The two adjacent housings considered for the measurement of the angle a4 between the two consecutive poles are housings of the first row.
[0084] As an example, angle and angular opening values are given with reference to [Fig. 3]. The lateral magnets of the first row 11 make an angle [31 of approximately 70° between them. The magnets of the second row 12 make an angle [32 of approximately 103° between them.
[0085] The angular opening a3 of the second row 12 is approximately 13 mm. The angular opening a5 of the first row 11 is approximately 30 mm.
[0086] Finally, a gap D between the two recesses of the lateral housings of the first row 11 is approximately 15 mm.
[0087] Of course, the shapes of the housings 10 and the recesses 15 could vary without departing from the scope of the present invention. By way of example, Figures 4a to 4d illustrate alternative embodiments.
[0088] In the example of [Fig.4a], the housings of the second row 12 are elongated at a point so as to reduce the distance W between the bottom of the second row and the first row.
[0089] In the example of [Fig.4b], the recesses 15 of the housings of the first row 12 are shortened, not protruding radially from the central housing.
[0090] In the example of [Fig.4c], the recesses 15 of the housings of the first row 12 are on the contrary elongated, ending in a semicircle.
[0091] In the example of [Fig.4d], the recesses 15 of the housings of the first row 12 are separated from the rest of the housing by a stop 17 for holding the permanent magnet.
[0092] In the embodiment of Figures 1 and 2, the lateral housings of the first row 11 are provided with permanent magnets, as is the central housing, these magnets all being identical.
[0093] In the embodiment illustrated in [Fig.5], the central housing of the first row 11 is provided with a permanent magnet smaller than the permanent magnets of the lateral housings, of length L4 less than the length L1 or the length L2.
[0094] As a further variant, as illustrated in [Fig.6], the central housing of the first row may be empty, being devoid of a permanent magnet.
[0095] In the embodiment illustrated in Figures 7a and 7b, some sheets of the rotor comprise deformable tabs 19 which each connect to a face of the corresponding housing, as illustrated in [Fig.7a], while other sheets of the stack do not comprise them, as illustrated in [Fig.7b]. In the example illustrated, only the lateral housings of the first rows and the housings of the second rows comprise such a deformable tab 19.
[0096] The deformable tabs 19 each extend into the corresponding housing. Each deformable tab 19 comprises a portion which is folded so as to be pressed against a small side of the corresponding magnet. The foldable portion of the deformable tab 19 is folded outside the plane of the sheets, along a folding axis of the deformable tab 19 extending in a plane parallel to the plane of the sheet.
[0097] In the examples described, the machine has a number of poles of 8. Of course, it does not go beyond the scope of the present invention if this number is different, for example 6.
Claims
Claims
1. Rotor (30) of a rotating electrical machine, comprising a rotor mass (33) comprising sheets stacked on top of each other, the rotor mass (33) comprising a plurality of housings (10), at least some of the housings, or even all of the housings, receiving one or more permanent magnets defining poles of the rotor, the housings of a pole being arranged in at least a first (11) and a second (12) row of housings, the first row (11) of housings comprising three housings arranged in a U, with a central housing and two lateral housings, a length (L2) of a largest rectangle inscribed in the central housing being equal to + / - 20% of the length (L1) of the largest rectangle inscribed in a lateral housing, at least one of the lateral housings, in particular the two lateral housings of the first row, comprising a recess (15) which extends from the lateral housing towards the central housing,the recess (15) being configured to protrude radially from the central housing, the housings of the second row (12) being arranged in a V, a ratio (BA) / B being between 10 and 30%, with B the width of the central housing and A the width of a housing of the second row (12).,
2. Rotor according to the preceding claim, the width (B) of the largest rectangle inscribed in the central housing being equal to + / - 50% of the width (B) of the largest rectangle inscribed in a lateral housing.
3. Rotor according to any one of the preceding claims, in which the lateral housings of the first row (11) are provided with permanent magnets.
4. Rotor according to any one of the preceding claims, the central housing of the first row (11) being provided with a permanent magnet smaller than the permanent magnets of the side housings.
5. Rotor according to any one of the preceding claims, wherein an angular opening (a3) of the second row is greater than or equal to twice the sum of the angular opening (al) between two consecutive poles and the angular opening (a2) between the first and second rows.
6. A rotor according to any preceding claim, in which an angular opening (a3) of the second row (12) is given by the following relation: a3 = k 2ir / (2p), where p is the number of pairs of poles of the rotor and k the polar opening coefficient, with the polar opening coefficient k which is included in the interval [22.5%; 37.5%], better in the interval [25%; 35%].
7. Rotor according to any one of the preceding claims, an angle (a4) between the adjacent housings of two consecutive poles being strictly greater than 0, being in particular between 5° and 35°, better still between 12° and 30°.
8. Rotor according to any one of the preceding claims, a width (X) of the recess (15) being between 0 mm and twice the width (B) of the central housing.
9. Rotor according to any one of the preceding claims, a radial dimension (W) between the bottom of the second row and the first row being between one time the width B of the central housing and three times the latter.
10. A rotor according to any preceding claim, the recess having an edge which extends at least partially parallel to an edge of the central housing.
11. Rotor according to any one of the preceding claims, at least one housing comprising at least one stop (17) for holding the permanent magnet intended to be received in the housing.
12. Rotor according to any one of the preceding claims, being devoid of circulation of cooling fluid in the housings.
13. A rotating electrical machine, comprising a stator and a rotor (30) as defined according to any one of the preceding claims.