Rotor of a rotating electrical machine
The rotor design for rotating electrical machines addresses performance losses by using clamping means and end discs with blades to secure the rotor body and magnets, improving cooling and structural integrity, and reducing noise.
Patent Information
- Application Number
- FR2020011355
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2020-11-05
- Publication Date
- 2025-06-20
- Estimated Expiration
- 2040-11-05
AI Technical Summary
Existing rotors for rotating electrical machines suffer from performance losses due to offset between the rotor body and the stator, and axial movement of magnets, which affects cooling efficiency and overall machine performance.
The rotor design incorporates clamping means to securely attach the end discs to the rotor body, preventing axial movement of the body and magnets, while the end discs with blades enhance cooling and structural rigidity.
This design effectively maintains the rotor's position relative to the stator, prevents magnet axial movement, improves cooling efficiency, and reduces noise, thereby enhancing the performance and reliability of the rotating electrical machine.
Smart Images
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Abstract
Description
Title of the invention: Rotor of a rotating electric machine
[0001] The invention relates to a rotor of a rotating electrical machine with cooling as well as to a rotating electrical machine equipped with such a rotor.
[0002] It is known from patent application US2019386537 a rotor for a rotating electrical machine comprising:
[0003] - a body comprising cavities and comprising a first end and a second end opposite in the direction of the axis of rotation A,
[0004] - magnets received in the cavities,
[0005] - a shaft on which the body is mounted,
[0006] - a first end disc comprising a first number of first blades capable of moving a fluid, in particular air, from a first radially inner position to a second radially outer position,
[0007] - a second end disc comprising a second number of first blades capable of moving a fluid, in particular air, from a third radially inner position to a fourth radially outer position.
[0008] The first end disc and second end disc are fixed to the shaft but do not allow axial clamping of the rotor. An offset of the rotor body relative to the end discs is thus possible. This offset can lead to a reduction in the performance of the rotating electrical machine. In addition, the rotor magnets are not held axially in the rotor. They can thus move axially relative to the body. The performance of the electrical machine can then be reduced.
[0009] The present invention aims to resolve all or part of these drawbacks.
[0010] The invention relates to a rotor for a rotating electrical machine having an axis of rotation and comprising:
[0011] - a body comprising cavities and comprising a first end and a second end opposite in the direction of the axis of rotation,
[0012] - magnets received in the cavities,
[0013] - a shaft on which the body is mounted,
[0014] - a first end disc comprising a first number of first blades capable of moving a fluid, in particular air, from a first radially inner position to a second radially outer position, the first end disc preventing the magnets from leaving the cavities through the first end of the body,
[0015] - a clamping means pressing the first end disc directly or indirectly on the first end of the body.
[0016] The use of a clamping means makes it possible to avoid the movement of the body relative to the first end disc. This absence of movement contributes to maintaining the position of the body relative to a stator of the rotating electrical machine. It is thus possible to limit the performance losses of the rotating electrical machine caused by an offset between the body of the rotor and the stator. The axial clamping of the end disc against the body also makes it possible to maintain the magnets in the cavities. This clamping is also improved by the use of an end disc comprising blades. Indeed, in addition to allowing the movement of a cooling fluid to cool the rotating electrical machine, the first blades allow stiffening of the first end disc. The axial support of the first end disc is thus possible even at a distance from the clamping means.
[0017] According to an additional characteristic of the invention, the rotor comprises a second end disc, the clamping means pressing the second end disc directly or indirectly on the second end.
[0018] The use of a second end disc pressing, by means of the clamping means, on the body allows an improvement in maintaining the position of the body relative to a stator of the rotating electrical machine. It also allows the magnets to be held in the cavities and prevents them from coming out through the second end.
[0019] According to an additional characteristic of the invention, the second end disc comprises a second number of second blades capable of moving a fluid, in particular air, from a third radially inner position to a fourth radially outer position.
[0020] The use of blades on the second end disc allows for improved cooling of the rotating electrical machine. It also allows for stiffening of the second end disc. Thus, the axial support of the second end disc is improved, particularly at a distance from the clamping means.
[0021] According to an additional characteristic of the invention, the first number of first blades and the second number of second blades are different and / or the first blades and / or the second blades are distributed circumferentially in an irregular manner.
[0022] A different number of first blades and second blades and / or the first blades and second blades distributed irregularly allows a reduction in the noise generated by the rotating electrical machine.
[0023] According to an additional characteristic of the invention, the first end disc comprises a first discoidal part from which the first blades extend, the first blades being in particular formed of material with the first discoidal part.
[0024] The use of first blades formed from material with the first discoidal part makes it possible to improve the rigidity of the first end disc. In addition, such an end disc makes it possible to limit the number of parts and simplify manufacturing and therefore reduce the cost of the first end disc.
[0025] According to an additional characteristic of the invention, the first end disc has a first thickness in the direction of the axis of rotation and the first discoid part has a second thickness in the direction of the axis of rotation, the ratio between the second thickness and the first thickness being between 0.2 and 0.6.
[0026] Such a ratio allows a first discoidal part of sufficient thickness to make machining and balancing of the rotor easier. It also allows good cooling performance to be maintained thanks to first blades that are sufficiently long in the axial direction.
[0027] According to an additional characteristic of the invention, the second end disc comprises a second discoidal part from which the second blades extend, the second blades being in particular formed of material with the second discoidal part.
[0028] The use of second blades formed from material with the second discoidal part makes it possible to improve the rigidity of the second end disc. In addition, such an end disc makes it possible to limit the number of parts and simplify manufacturing and therefore reduce the cost of the second end disc.
[0029] According to an additional characteristic of the invention, the second end disc has a third thickness in the direction of the axis of rotation and the second discoid part has a fourth thickness in the direction of the axis of rotation, the ratio between the fourth thickness and the third thickness being between 0.2 and 0.6.
[0030] Such a ratio allows a second discoidal part of sufficient thickness to make machining and balancing of the rotor easier. It also allows good cooling performance to be maintained thanks to second blades that are sufficiently long in the axial direction.
[0031] According to an additional characteristic of the invention, the shaft comprises a shoulder on which the second end of the body bears directly or indirectly in the direction of the axis of rotation A, the body being gripped between the clamping means and the shoulder.
[0032] Such a shoulder allows precise positioning of the rotor body, the first balancing disc and, where appropriate, the second balancing disc relative to the shaft and therefore relative to the stator. It is thus possible to improve the performance and cooling of the rotating electrical machine.
[0033] According to an additional characteristic of the invention, the shaft comprises a threaded zone and the tightening means is a nut screwed onto the threaded zone.
[0034] Such a clamping means, by its central position, allows the clamping force to be well distributed between the end disc(s) and the body. It also allows clamping with a very limited number of parts.
[0035] According to an additional characteristic of the invention, the clamping means comprises a rod, in particular a threaded rod parallel to the axis of rotation A, passing through a hole formed in the body.
[0036] The invention also relates to an electrical machine comprising:
[0037] - a stator,
[0038] - a rotor as described previously.
[0039] In all of the above, the rotor may comprise any number of pole pairs, for example six or eight pole pairs.
[0040] In all of the above, the rotating electrical machine may have a stator having a polyphase electrical winding, for example formed by wires or by conductive bars connected to each other.
[0041] The rotating electrical machine may comprise a power electronic component, capable of being connected to the on-board network of a vehicle. This power electronic component comprises, for example, an inverter / rectifier making it possible, depending on whether the rotating electrical machine operates as a motor or as a generator, to charge an on-board network of the vehicle or to be electrically powered from this network.
[0042] The rotating electrical machine may also comprise a pulley or any other means of connection to the rest of a powertrain of the vehicle. The electrical machine is for example connected, in particular via a belt, to the crankshaft of a thermal engine of the vehicle. Alternatively, the rotating electrical machine is connected to other locations of the powertrain, for example to the input of a gearbox from the point of view of the torque transmitted to the wheels of the vehicle, to the output of the gearbox from the point of view of the torque transmitted to the wheels of the vehicle, at the gearbox from the point of view of the torque transmitted to the wheels of the vehicle, or even on the front axle or the rear axle of this powertrain.
[0043] The invention may be better understood by reading the following description of non-limiting examples of its implementation and by examining the attached drawing in which:
[0044] - [Fig.l] [Fig.l] represents a partial schematic sectional view of a machine rotating electric motor comprising a rotor according to a first embodiment of the invention,
[0045] - [Fig.2] [Fig.2] represents an exploded view of the rotor according to the first mode of realization of the invention,
[0046] - [Fig.3] [Fig.3] represents a view of the rotor according to the first embodiment of the invention,
[0047] - [Fig.4] [Fig.4] represents an exploded view of a rotor according to a second mode of realization of the invention,
[0048] - [Fig.5] [Fig.5] represents a view of the rotor according to the second embodiment of the invention.
[0049] In all the figures, identical elements or elements providing the same function bear the same reference numbers. The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment or that the characteristics apply only to a single embodiment. Single characteristics of different embodiments may also be combined or interchanged to provide other embodiments.
[0050] [Fig.l] represents a partial schematic sectional view of a rotating electrical machine 1 having an axis of rotation A according to a first embodiment of the invention. The rotating electrical machine 1 comprises a stator 2 and a rotor 3 in a casing 32. The casing comprises for example a first bearing 5, a second bearing 6 and a tubular spacer 7. The tubular spacer 7 is for example clamped between the first bearing 5 and the second bearing 6, for example by means of tie rods not shown between the first bearing 5 and the second bearing 6. The stator is fixed inside the casing 32, for example mounted tightly in the tubular spacer 7.
[0051] The stator comprises a stator body 9 and a winding 8. The stator body 9 comprises, for example, a stack of magnetic sheets. For example, the winding 8 comprises electrical conductors, an active part of which passes through notches formed in the body 9 and a connection part or bun 10 is formed outside the notches. The winding 8 is, for example, a hairpin-type winding.
[0052] The rotor 3 comprises a shaft with an axis of rotation A. The shaft is guided in rotation by a first bearing 11 mounted in the first bearing and a second bearing 12 mounted in the second bearing 6. A drive element 13, for example a pulley or a gear, is fixed to the shaft 4.
[0053] In another embodiment not shown, the shaft 4 is guided in rotation relative to the first bearing and the second bearing by means of other known rotational guiding means, for example plain bearings.
[0054] The rotor 3 also comprises:
[0055] - a body 15 mounted on the shaft 4 and comprising cavities 24 as well as a first end 33 and a second end 34 opposite in the direction of the axis of rotation A,
[0056] - magnets 23 received in the cavities 24,
[0057] - a first end disc 16 comprising a first number of first blades 18 capable of moving a fluid, in particular air, from a first radially inner position to a second radially outer position, the first end disc 16 preventing the magnets 23 from leaving the cavities 24 via the first end 33 of the body 15,
[0058] - a clamping means 22 pressing the first end disc 16 directly or indirectly on the first end 33 of the body 15.
[0059] The body 15 of the rotor comprises, for example, a layer of magnetic sheets.
[0060] The body 15 may comprise a central opening crossed by the shaft 4.
[0061] The cavities 24 extend for example in the direction of the axis of rotation A. In the embodiments of the invention shown in the figures, the cavities 24, and therefore the magnets 23, are arranged two by two in a V.
[0062] In another embodiment not shown, the cavities also extend in the direction of the axis of rotation A but have a radial orientation.
[0063] In another embodiment not shown, the cavities are oriented perpendicular to a radius of the rotor so that the North pole and the South pole of each magnet are radially opposed. For example, the South pole is oriented towards the axis of rotation, i.e. radially inwards, while the North pole is oriented radially outwards.
[0064] The cavities 24 extend for example from the first end 33 to the second end 34 of the body 15.
[0065] As seen previously, in the embodiments of the invention shown in the figures, the cavities 24 extend in the direction of the axis of rotation A. In another embodiment not shown, the cavities extend in a helix having as their axis, the axis of rotation A.
[0066] In the embodiments shown in the figures, the magnets 23 are formed by a succession of elementary magnets. In another embodiment of the invention not shown, each magnet 23 is a single piece. In another embodiment of the invention not shown, at least one magnet is a single piece and at least one magnet is composed of elementary magnets.
[0067] The first end disc 16 comprises a first discoidal portion 20 from which the first blades 18 extend. The first discoidal portion 20 may comprise openings, for example to reduce the inertia of the rotor.
[0068] The first blades 18 are for example formed from a material with the first discoidal part 20. The first end disc is for example produced by molding an aluminum alloy or plastic material such as a thermoplastic or a thermoset sand.
[0069] The first blades 18 are for example inclined so as to form with the first discoidal part 20 a so-called action fan as in the embodiments shown in the figures. In another embodiment not shown, the first blades are inclined in an opposite direction so as to form with the discoidal part a so-called reaction fan. In another embodiment not shown, the first blades are radial.
[0070] The rotor may also comprise a second end disc 17. The clamping means 25 presses the second end disc 17 directly or indirectly onto the second end 34 of the body 15 of the rotor 3.
[0071] The second end disc 17 comprises a second number of second blades 19 capable of moving a fluid, in particular air, from a third radially inner position to a fourth radially outer position.
[0072] The second end disc 17 comprises a second discoidal portion 21 from which the second blades 19 extend. The second discoidal portion 21 may comprise openings, for example, to reduce the inertia of the rotor.
[0073] The second blades 19 are for example formed in one piece with the second discoidal part 21. The second end disc 17 is for example produced by molding an aluminum alloy or plastic material such as a thermoplastic or a thermoset sand.
[0074] The second blades 19 may be inclined so as to form with the second discoidal part 21 a so-called action fan as in the embodiments shown in the figures. In another embodiment not shown, the second blades are inclined in an opposite direction so as to form with the second discoidal part a so-called reaction fan. In another embodiment not shown, the second blades are radial.
[0075] In the embodiments shown in the figures, the first number of first blades 18 and the second number of second blades 19 are different. For example, the first number and the second number do not have a common divisor. For example, the first number is 9 and the second number is 7.
[0076] In another embodiment not shown, the first and / or the second blades are distributed circumferentially in an irregular manner.
[0077] In another embodiment not shown, the first number and the second number are different and the first blades and the second blades are circumferentially distributed in an irregular manner.
[0078] The first end disc 16 has a first thickness E1 in the direction of the axis of rotation A. The first discoidal part 20 has a second thickness D1 in the direction of the axis of rotation A. The ratio between the second thickness D1 and the first thickness E1 is for example between 0.2 and 0.6. The first end disc 16, in particular the first discoidal part 20, can thus, for example, be machined, in particular drilled, to balance the rotor 3.
[0079] The second end disc 17 has a third thickness E2 in the direction of the axis of rotation A. The second discoidal part 21 has a fourth thickness D2 in the direction of the axis of rotation A. The ratio between the fourth thickness D2 and the third thickness E2 is for example between 0.2 and 0.6. The second end disc 17, in particular the second discoidal part 21, is thus capable of being machined, in particular drilled, to balance the rotor 3.
[0080] The first blades 18 of the first end disc 16 and the second blades 19 of the second end disc 17 are for example located axially, that is to say in the direction of the axis of rotation A, at the level of the coil ends 10 of the winding 8. Such a position allows the coil ends to be cooled by the fluid displaced by the blades 18, 19.
[0081] In the first embodiment of the invention shown in [Fig.l], [Fig.2] and [Fig.3], the shaft 4 comprises a shoulder 14 on which the second end of the body bears in the direction of the axis of rotation A. The support may be indirect as in the first embodiment of the invention in which the second end disc 17 has an interface role between the body 15 and the shoulder 14. In another embodiment not shown, the support is direct. The body is clamped between the clamping means 25 and the shoulder 14.
[0082] In the first embodiment of the invention, the tightening means is a nut 25. The nut 25 is screwed onto a threaded zone 25 of the shaft 4. A tightening force of the nut 25 is thus transmitted by the nut 25 to the first end washer 16 then to the body 15.
[0083] In the first embodiment, the shoulder 14 is formed in one piece with the shaft 4.
[0084] In another embodiment not shown, the shoulder is attached to the shaft 4.
[0085] The shaft 4 may comprise a groove 26 in which a key arranged to prevent rotation of the body relative to the shaft can engage. In the first embodiment, this key is formed of material in the body 15. The key is then a first protrusion 28 in the central opening of the body 15. The protrusion is oriented radially towards the inside of the body 15.
[0086] A second protrusion 27, similar to the first protrusion 28, may be formed in the first end disc 16 to prevent rotation of the first end disc 16 relative to the shaft 4.
[0087] A third protrusion 29, similar to the second protrusion 27, may be formed in the second end disc 17 to prevent rotation of the second end disc 17 relative to the shaft 4.
[0088] The second embodiment of the invention, shown in [Fig.4] and [Fig.5] is similar to the first embodiment of the invention. However, in the second embodiment, the clamping means as well as the connection between the shaft 4 and the body 15 of the rotor 3 are different.
[0089] The clamping means may comprise a rod 30, in particular a threaded rod parallel to the axis of rotation A, passing through a first hole 38 formed in the body.
[0090] A second hole 35 formed in the first end disc 16 and a third hole 36 formed in the second end disc 17 are also crossed by the rod 30. Thus the body 15 is clamped between the first end disc 16 and the second end disc 17.
[0091] A plurality of rods 30 can be used as in the second embodiment of the invention. In this embodiment, the rod 30 is the rod of a screw. A nut 31 is screwed onto the rod 30 of the screw so as to grip the body 15, the first end disc 16 and the second end disc 17 between a head 37 of the screw and the nut 31. In the embodiment shown in [Fig.4] and [Fig.5], the head 37 of the screw bears directly on the first end disc 16. In another embodiment not shown, the support between the head 37 of the screw and the first balancing disc is indirect, in particular by the use of a washer. Similarly, the support between the nut 31 and the second end disc 17 can be direct or indirect, in particular by the use of a washer.
[0092] In another embodiment of the invention not shown, the head of the screw is in direct or indirect contact with the second balancing disc and the nut is in direct or indirect contact with the first balancing disc.
[0093] The body is for example force-fitted onto the shaft so as to ensure axial retention of the body 15, the first end washer 16 and the second end washer 17 on the shaft 4. A rotational connection between the body 15 and the shaft 4 can also be ensured by this fitting. In the second embodiment of the invention shown in Figures 4 and [Fig.5], a groove 26 on the shaft 4 and a first protrusion 28, as in the first embodiment, makes it possible to reinforce the rotational connection between the body 15 and the shaft 4.
[0094] In the second embodiment, a shoulder 14 may be formed on the shaft 4 as in the first embodiment. However, this shoulder has a different function. It allows the axial positioning of the rotor body on the shaft during fitting.
[0095] In a variant of the second embodiment not shown, a shoulder formed on the shaft is interposed tightly in the direction of the axis of rotation between the body and the second end disc. The tightening is for example carried out using the tightening means of the second embodiment described above.
[0096] In the various embodiments of the invention described above, the rotating electrical machine 1 can be cooled by a cooling liquid. For example, a chamber for the circulation of the cooling liquid is formed in the spacer 7. The casing 32 can then be closed, i.e. the casing 32 does not include an opening for the circulation of ambient air between the inside and the outside of the rotating electrical machine 1. The first blades 18 and, where appropriate, the second blades 19 allow, for example, mixing of the air inside the rotating electrical machine 1. Measurements have shown that such mixing can reduce the temperature of the coils 10 by 12°C and the temperature of the rotor 3 by 4°C.
[0097] Alternatively, the rotating electrical machine 1 is cooled by a coolant, for example oil, which circulates inside the casing. The first blades 18 and, where appropriate, the second blades 19 promote the circulation of the coolant in the rotating electrical machine 1. The rotating electrical machine 1 may be connected to a cooling circuit.
[0098] Alternatively, the casing of the rotating electrical machine 1 has openings. The first blades 18 and / or the second blades 19 promote the circulation of ambient air between the inside and the outside of the rotating electrical machine 1.
Claims
Claims
1. Rotor (3) for a rotating electrical machine (1) having an axis of rotation (A) and comprising: a. a body (15) comprising cavities (24) and comprising a first end (33) and a second end (34) opposite in the direction of the axis of rotation A, b. magnets (23) received in the cavities (24), c. a shaft (4) on which the body (15) is mounted, d. a first end disc (16) comprising a first number of first blades (18) capable of moving a fluid, in particular air, from a first radially inner position to a second radially outer position, the first end disc (18) preventing the magnets (23) from leaving the cavities (24) through the first end (33) of the body (15), the first end disc (16) comprises a first discoidal portion (20) from which the first blades (18) extend, the first blades (18) being in particular formed in one piece with the first discoidal portion (20), e. a clamping means (22, 37) pressing the first end disc directly or indirectly on the first end of the body. in which the shaft (4) comprises a shoulder (14) on which the second end (34) of the body (15) bears directly or indirectly in the direction of the axis of rotation A, the body (15) being clamped between the clamping means (22) and the shoulder (14), and in which the shaft (4) comprises a threaded zone (25) and the clamping means is a nut (22) screwed onto the threaded zone (25) wherein the first end disc (16) has a first thickness (El) in the direction of the axis of rotation (A) and the first discoidal part (20) has a second thickness (Dl) in the direction of the axis of rotation (A), the ratio between the second thickness (Dl) and the first thickness (El) being between 0.2 and 0.
6.
2. Rotor (3) according to the preceding claim comprising a second end disc (17), the clamping means (22, 37) pressing the second end disc (17) directly or indirectly on the second end (34).
3. Rotor (3) according to the preceding claim in which the second end disc (17) comprises a second number of second blades (19) capable of moving a fluid, in particular air from a third radially inner position to a fourth radially outer position.
4. Rotor (3) according to the preceding claim in which the first number of first blades (18) and the second number of second blades (19) are different and / or the first blades (18) and / or the second blades (19) are distributed circumferentially in an irregular manner.
5. Rotor (3) according to claim 2 in which the second end disc (17) comprises a second discoidal part (21) from which the second blades (19) extend, the second blades (19) being in particular formed in material with the second discoidal part (21).
6. Rotor (3) according to the preceding claim in which the second end disc (17) has a third thickness (E2) in the direction of the axis of rotation (A) and the second discoidal part (21) has a fourth thickness (D2) in the direction of the axis of rotation (A), the ratio between the fourth thickness (D2) and the third thickness (E2) being between 0.2 and 0.
6.
7. Electrical machine (1) comprising: a. a stator, b. a rotor (3) according to one of the preceding claims.