Nacelle system for an electric machine

Abstract

The invention relates to a nacelle system (8) for an electric machine (2) provided with cooling fins (6), which comprises a fairing (10) configured to match the shape of the electric machine (2) and an adjustment device (12) configured to hold the fairing (10) and press it against the cooling fins (6) for cooling the electric machine (2), the fairing (4) comprising at least one portion (14) of fairing (10), the adjustment device (12) comprising at least one connection means (16) arranged between two ends (20) of portion (14) of fairing (10). In particular, the nacelle system (8) enables the electric machine (2) to be cooled more effectively by improved air circulation and improves the performance of the electric machine (2).

Description

[0001] DESCRIPTION

[0002] TITLE: Nacelle system for an electric machine

[0003] Technical field

[0004] The present invention relates to a nacelle system for improving the cooling of cooling fins of an electrical machine.

[0005] In particular, the present invention relates to a system for increasing the amount of heat evacuated by the fins.

[0006] Generally, the present invention applies to any machine cooled by a fluid surrounding the electric machine. However, one application of the invention relates to the cooling of an aircraft electric motor.

[0007] Previous techniques

[0008] During operation, an aircraft engine is subject to thermal stress and therefore requires cooling to ensure optimal operation. An electric motor requires even more efficient cooling as the engine temperature strongly influences the engine's performance. In the case of air circulation cooling, the engine is advantageously equipped with thermally conductive fins increasing the heat exchange surface between the engine and the air in which the aircraft operates.

[0009] The aircraft may include a fairing near the engine, for example surrounding the engine. The fairing is generally positioned to protect the engine from possible impacts but makes engine cooling ineffective. In addition, the airflow reaching the fins does not allow sufficient heat to be extracted from the fins and the engine cooling is not efficient. This situation can lead to oversizing of the engine and therefore excess weight of the aircraft.

[0010] Presentation of the invention The present invention therefore aims to overcome all or part of the aforementioned drawbacks and proposes to improve the cooling of cooling fins of an electrical machine by allowing efficient cooling of the fins.

[0011] The present invention relates to a nacelle system for an electric machine provided with cooling fins, comprising a fairing configured to match the shape of the electric machine and an adjustment device configured to hold the fairing and press it around the cooling fins of the electric machine, the fairing comprising at least one fairing portion, the adjustment device comprising at least one connecting means arranged between two ends of the fairing portion.

[0012] The nacelle system allows, thanks to the adjustment device, to be positioned as close as possible to the fins and to optimize the fluid flows surrounding the electric machine in order to increase the quantity of heat exchanged between the fins and the fluids to which the calories are evacuated. In particular, the fairing is positioned so as to participate in the transfer of heat between the fins and the air, the fairing allows for example to direct an air flow cooling the fins.

[0013] Advantageously, the fairing comprises holes distributed along a periphery of the fairing, the adjustment device comprising fixing means arranged in the holes so as to fix the fairing to the electrical machine.

[0014] Preferably, the connecting means comprises a tie rod and at least two brackets, the two brackets being joined by the tie rod.

[0015] In one embodiment, the fairing comprises several fairing portions, the adjustment device comprising several connecting means each arranged between two ends of the fairing portions.

[0016] Optionally, the system includes an interface material in contact with the fairing and configured to contact the cooling fins, the interface material being configured to protect the fins and / or provide a thermal interface between the fins and the fairing.

[0017] Advantageously, the fairing comprises a thermally conductive material.

[0018] Preferably, the adjustment device comprises locking means for locking the adjustment of the adjustment device.

[0019] Optionally, the locking means includes a self-locking nut.

[0020] The present invention also relates to an electrical machine comprising a body, thermally conductive fins distributed around the body, and a nacelle system as defined previously.

[0021] Advantageously, the fairing comprises a material having a coefficient of thermal expansion corresponding to the coefficient of thermal expansion of the material of the body of the electric machine.

[0022] Brief description of the drawings

[0023] Other objectives, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

[0024] [Fig 1] schematically illustrates an electric machine according to the invention;

[0025] [Fig 2] schematically illustrates an enlargement of an area of ​​Figure 1 centered on the connecting means;

[0026] [Fig 3] schematically illustrates a nacelle system according to a first embodiment of the invention; and

[0027] [Fig 4] schematically illustrates a nacelle system according to a second embodiment of the invention.

[0028] Detailed description of at least one embodiment

[0029] Figure 1 schematically represents an electric machine 2. The electric machine 2 comprises a cylindrical body 4, thermally conductive fins 6 distributed around the body 4 and a nacelle system 8. The nacelle system 8 comprises a fairing 10 configured to match the shape of the electric machine 2 and an adjustment device 12 configured to hold the fairing 10 and press it around the fins 6. The nacelle system 8 is understood to mean the assembly composed of the fairing 10 and the adjustment device 12.

[0030] The electric machine 2 comprises, for example, an aircraft engine provided with thermally conductive fins 6 configured to carry out a heat exchange between the fins 6 and the air in which the aircraft is moving.

[0031] The nacelle system 8 is intended to improve the cooling of the cooling fins 6 of the electric machine 2.

[0032] The fairing 10 comprises a portion 14 of fairing 10, for example a thin metal sheet, for example 1 mm thick, formed for example from an aluminum alloy. In another embodiment, the portion 14 of fairing 10 is formed from another metallic, or polymer, or composite, or thermoplastic, or thermosetting material or from an aluminum alloy. The portion 14 of fairing 10 is slightly flexible and held in shape by the adjustment device 12 to best fit the fins 6 of the electric machine 2.

[0033] Here the shape is substantially cylindrical so that the fairing 10 takes the form of an annular ring of defined longitudinal dimension, for example of the same dimension as a dimension of the electric machine 2 along the longitudinal axis L, and of circular or elliptical cross-section, or substantially similar to the cross-section of the electric machine 2.

[0034] The adjustment device 12 comprises at least one connecting means 16. The connecting means 16 comprises, for example, a tie rod 18 connecting two ends 20 of the portion 14 of the fairing 10 so as to bring the two ends 20 together or to maintain the two ends 20 at a constant distance from each other. Advantageously, the adjustment device 12 comprises a bracket 22 arranged on one end 20. Preferably, the adjustment device 12 comprises a second bracket 22 arranged on the second end 20, the two brackets 22 being connected by the tie rod 18. The adjustment device 12 makes it possible, for example, to bring the two ends 20 of the portion 14 of the fairing 10 into contact. The brackets 22 also make it possible to reinforce the fairing 10.

[0035] In the example of Figure 1, the nacelle system 8 comprises a portion 14 of fairing 10 held by three assembly rods 18 holding the fairing 10 in a cylinder shape of constant circular section along the longitudinal axis of the fairing 10. In addition, the adjustment device 12 makes it possible to hold the fairing 10 in a shape substantially similar to the cross section of the electric machine 2. Advantageously, the assembly rods 18 are removable so as to be able to separate the two ends 20 and thus to be able to remove the fairing 10 from the electric machine 2.

[0036] A tie rod 18 is for example an adjustable mechanical part made with a screw system and / or lever closure and / or rocker closure. In particular, a tie rod 18 connects the brackets 22, making it possible to adjust the distance between the brackets 22. In the example of Figure 1, each of the three tie rods 18 connects two brackets 22 so as to keep the two brackets 22 at a constant distance from each other.

[0037] Preferably, the fairing 10 comprises holes 24 perforated in the material of the fairing 10 or made during the shaping of the fairing 10, for example during a stamping process, and distributed along a periphery of the fairing 10, for example uniformly. Advantageously, the adjustment device 12 comprises fixing means 26 configured to be arranged in the holes 24 and to fix the fairing 10 to the electric machine 2, preferably in contact with the fins 6 so as to optimize fluid flows for cooling the electric machine 2. The fixing means 26 comprise, for example, screws and / or columns and / or washers. In one embodiment, the holes 24 are distributed non-uniformly over the fairing 10. Preferably, the fins 6 are in contact with the fairing 10 so that the fairing 10 also acts as a heat diffuser.

[0038] In one embodiment, the nacelle system 8 comprises an interface material 28 in contact with the fairing 10 on the one hand and with the fins 6 on the other hand so as to protect the fins 6 from contact with the fairing 10, in particular in the case of fragile fins 6.

[0039] The interface material 28 comprises, for example, a foam or a soft material such as Teflon. Preferably, the interface material 28 comprises a thermally conductive material covering an inner surface of the fairing 10. In addition, the interface material 28 transmits the heat evacuated by the fins 6 to the fairing 10. The interface material 28 thus participates in the cooling of the fins 6 by forming a thermal interface between the fins 6 and the fairing 10.

[0040] Advantageously, the adjustment device 12 makes it possible to place the fairing 10 in support on the fins 6 so that the force exerted by the fairing 10 on the fins 6 is distributed substantially uniformly over the fins 6.

[0041] The fairing 10 is for example fixed to the electric machine 2 by removable fixing means 26 so as to be able to separate the fairing 10 from the electric machine 2. In addition, the fixing means 26 maintain the fairing 10 in a substantially cylindrical shape around the fins 6.

[0042] When the electric machine 2 is housed in the fairing 10, the fairing 10 makes it possible to channel the air along a surface of the fins 6 so as to increase the quantity of heat exchanged between the fins 6 and the air. In addition, an air flow is directed towards the fins 6 and the cooling of the electric machine 2 is improved in particular thanks to a reduction in pressure losses and / or a reduction in air leaks out of the fins 6. Advantageously, the air flow is concentrated exclusively in the fins 6. In addition, the heat exchange surface of the fins 6 when the electric machine 2 is housed in the fairing 10 is greater than the heat exchange surface of the fins 6 when the electric machine 2 is not housed in the fairing 10.

[0043] Optionally, openings (not shown) are made in the material of the fairing 10 so as to increase the flow of air cooling the fins 6 via an import of secondary air.

[0044] Air ducting helps improve the performance of the electric machine. For example, in the case of an aircraft engine, particularly an electric one, ducting helps increase the engine's ability to provide power to propel the aircraft.

[0045] Preferably, the adjustment device 12 allows the fairing 10 to perfectly match the shape of the electric machine 2 provided with fins 6 so that all the available air cools the fins 6.

[0046] Advantageously, the fairing 10 comprises a thermally conductive material so as to dissipate the heat emitted by the fins 6 and transmitted to the fairing 10. The fairing 10 comprises in this case a material having a coefficient of thermal expansion corresponding to the coefficient of thermal expansion of a material of the electric machine 2, corresponding in the case of the aircraft engine to the coefficient of thermal expansion of a material of the body 4 of the aircraft engine.

[0047] Furthermore, the coefficient of thermal expansion of the material of the fairing 10 is equal to the coefficient of thermal expansion of the material of the electric machine 2. Preferably, the material of the fairing 10 is the same as that forming the electric machine 2 so that the thermal expansions of the electric machine 2 and of the fairing 10 are of the same nature.

[0048] Figure 2 schematically shows an enlargement of an area of ​​Figure 1 representing in particular a detailed view of a part of the adjustment device 12. The adjustment device 12 comprises a tie rod 18 connecting two ends 20 of the fairing 10 and a locking means 30 so as to lock the adjustment of the tie rod 18. The locking means 30 is configured to lock the adjustment of the adjustment device 12. The locking means 30 makes it possible, for example, to avoid relative movements between the fairing 10 and the adjustment device 12 during vibrations of the fairing 10 and / or the electric machine 2.

[0049] The locking means 30 comprises, for example, a nut provided with a device preventing the nut from loosening without preventing the nut from being disassembled. The locking means 30 comprises, for example, a slotted nut and / or a nut with an incorporated ring and / or a locking nut and / or a self-locking nut.

[0050] The adjustment device 12 comprises a first bracket 22 arranged on one end 20, the end 20 comprising a flanged edge 32. The flanged edge 32 makes it possible, for example, to reinforce the end 20, to protect a user when installing the nacelle system 8 and to facilitate the alignment of the two ends 20 of the fairing 10. The flanged edge 32 allows a sealed junction of the two ends 20 of the fairing 10.

[0051] Advantageously, the bracket 22 includes an access opening 34 opposite the tie rod 18 so as to facilitate access to the tie rod 18 and therefore to facilitate its installation.

[0052] The adjustment device 12 comprises a fixing device 36 provided with a bracket 22, the fixing device 36 being arranged on the second end 20. The fixing device 36 makes it possible to reinforce the hold of the tie rod 18 on the second end 20.

[0053] Figure 3 schematically shows the nacelle system 8 of Figure 1 removed from the electric machine 2. The removal of the fairing 10 from the electric machine 2 is for example facilitated by the use of an assembly tie rod 18 as described previously.

[0054] In another embodiment shown schematically in FIG. 4, the fairing 10 of the nacelle system 8 comprises two portions 14 of fairing 10 of identical dimensions. In another embodiment, the portions 14 of fairing 10 may be different in number and of different dimensions from each other. Optionally, the portions 14 of fairing 10 comprise different materials, for example a thermoplastic material, a thermosetting material, a composite material or an aluminum alloy.

[0055] The portions 14 of fairing 10 are connected to each other by several connecting means 16. The nacelle system 8 shown comprises two identical connecting means 16. In another embodiment, the nacelle system 8 comprises a different number of connecting means 16, the connecting means 16 being identical or different.

[0056] In Figure 4, each connecting means 16 is arranged between two portions 14 of fairing 10 so that the portions 14 of fairing 10 form the fairing 10. More precisely, each connecting means 16 is arranged between two ends 20 of different portions 14 of fairing 10. The connecting means 16 comprise for example assembly rods 18, and / or screws, and / or nuts and / or rivets. Advantageously, the connecting means 16 are removable so as to be able to dissociate the portions 14 of fairing 10.

[0057] In the embodiment illustrated in Figure 4, each connecting means 16 comprises three tie rods 18 for assembling the fairing 10. Each tie rod 18 is arranged between two brackets 22. The number of portions 14 of fairing 10 makes it possible, for example, to best adjust the fairing to the shape of the electric machine 2 against which the fairing 10 is intended to be pressed. The number of connecting means 16 and their nature guarantee, for example, that the fairing 10 is properly pressed against the fins 6 of the electric machine 2 and / or that the adjustment of the fairing 10 around the electric machine 2 will not be modified when the electric machine 2 is used.

[0058] In another embodiment, the connecting means 16 is simply a hinge, or any other method of attaching the portions 14 of the fairing 10 to each other. At least one connecting means 16 remains adjustable as described previously.

[0059] In another embodiment, the adjustment device 12 makes it possible to maintain the fairing 10 in a shape corresponding to an electric machine 2 of non-cylindrical shape so that the fairing 10 is arranged around the fins 6 of the electric machine 2, in particular by means of several portions 14 of fairing 10 and connecting means 16.

[0060] In a particular embodiment, a fairing as described above is adapted for example to an electric motor and / or to a heat engine and / or to a generator and / or to a fan and / or to an exchanger. The electric machine 2 comprises for example a smart engine comprising an electric motor and its electronic control member advantageously used in the aeronautical field. In one embodiment, an aircraft engine comprising a nacelle system 8 as defined above forms a light and compact aircraft engine module ready to be installed in an aircraft.

[0061] In particular, the structure of the engine module ensures efficient engine cooling, regardless of the aircraft in which the engine module is installed.

[0062] The installation of the engine module in an aircraft is facilitated in particular thanks to the modular nature of the engine module, the efficient and autonomous cooling of the engine module, and the removable nature of the nacelle system 8.

Claims

CLAIMS 1. Nacelle system (8) for an electric machine (2) provided with cooling fins (6) characterized in that it comprises a fairing (10) configured to match the shape of the electric machine (2) and an adjustment device (12) configured to hold the fairing (10) and press it around the cooling fins (6) of the electric machine (2), the fairing (4) comprising at least one portion (14) of fairing (10), the adjustment device (12) comprising at least one adjustable connecting means (16) arranged between two ends (20) of portion (14) of fairing (10).

2. System (8) according to claim 1, in which the fairing (10) comprises holes (24) distributed along a periphery of the fairing (10) and in which the adjustment device (12) comprises fixing means (26) arranged in the holes (24) so ​​as to fix the fairing (10) to the electric machine (2).

3. System (8) according to any one of claims 1 and 2, in which the connecting means (16) comprises an assembly tie rod (18) and at least two brackets (22) each arranged on one end (20) of the portion (14) of the fairing (10), the two brackets (22) being joined by the assembly tie rod (18).

4. System (8) according to any one of claims 1 to 3, in which the fairing (10) comprises several portions (14) of fairing (10), the adjustment device (12) comprising several connecting means (16) each arranged between two ends (20) of portions (14) of fairing (10).

5. System (8) according to any one of claims 1 to 4, comprising an interface material (28) in contact with the fairing (10) and configured to be in contact with the cooling fins (6), the interface material (28) being configured to protect the fins (6) and / or allow a thermal interface between the fins (6) and the fairing (10).

6. System (8) according to any one of claims 1 to 5, wherein the fairing (10) comprises a thermally conductive material.

7. System (8) according to any one of claims 1 to 6, wherein the adjustment device (12) comprises locking means (30) for locking the adjustment of the adjustment device (12).

8. System (8) according to claim 7, in which the locking means (30) comprises a self-locking nut.

9. Electrical machine (2) comprising a body (4), fins (6) thermally conductive distributed around the body (4), and a nacelle system (8) according to any one of claims 1 to 8.

10. An electric machine (2) according to claim 9, wherein the shroud (10) comprises a material having a coefficient of thermal expansion corresponding to the coefficient of thermal expansion of the material of the body (4) of the electric machine (2).

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