Housing for rotating electrical machine, rotating electrical machine and associated manufacturing process

Abstract

Housing for rotating electrical machine, rotating electrical machine and associated manufacturing method The present invention relates to a housing (9) for a rotating electrical machine (1) comprising a body (11) including a side wall (11a) adapted to support in rotation a rotor shaft (5) of a rotating electrical machine (1) via a first bearing (7a) to form a first bearing and a longitudinal wall (11b) whose inner surface is adapted to carry a stator (15) of a rotating electrical machine (1), in which the body (11) includes a cooling chamber (19) adapted to receive a cooling fluid, the cooling chamber (19) extending into the longitudinal wall (11b) to cool the stator (15) and into the side wall (11a) to cool the first bearing (7a).

Description

Title of the invention: Housing for a rotating electrical machine, rotating electrical machine and associated manufacturing method

[0001] The invention relates to a rotating electrical machine casing and a rotating electrical machine comprising such a casing as well as a method of manufacturing such a casing.

[0002] Rotating electrical machines are widely used in industry and particularly in the automotive sector, whether for the propulsion of electric vehicles or for the various vehicle equipment.

[0003] The use of rotating electrical machines induces heating due to friction during high-speed rotation of the rotor as well as electrical losses.

[0004] In order to allow proper operation of the rotating electrical machine, it is therefore necessary to limit its heating and in particular heating of the bearings due to the presence of grease which tends to lose its lubricating properties beyond a certain temperature so that significant and prolonged heating beyond this temperature can lead to seizure of the rotating electrical machine.

[0005] Limiting heating is also necessary due to the presence of electronic components used for controlling the rotating electrical machine.

[0006] In order to cool the rotating electrical machine, it is known to use a cooling fluid circuit arranged near the areas to be cooled to efficiently evacuate a large part of the heat produced.

[0007] However, such a cooling circuit can be difficult to produce and implement since it requires perfect sealing to avoid any risk of degradation of the electronic components used for controlling the rotating electrical machine.

[0008] Such sealing generally requires the use of gaskets, particularly if the circuit is to cool different parts of the rotating electrical machine, for example the stator and the bearings. These gaskets must be placed precisely during assembly of the rotating machine and must be maintained and / or changed during the lifetime of the rotating electrical machine to maintain their sealing.

[0009] Furthermore, it is appropriate to limit the overall size of the rotating electrical machine despite the presence of the cooling circuit to facilitate its integration, particularly in the case of use in a motor vehicle.

[0010] It is therefore necessary to find a solution that allows effective cooling of a rotating electrical machine without complicating the cooling process. Manufacture of the rotating electrical machine and in particular the assembly of the different parts in order to limit the labor required for manufacturing and by limiting the size of the rotating electrical machine.

[0011] To this end, the present invention relates to a casing for a rotating electrical machine comprising a body comprising a side wall capable of supporting in rotation a rotor shaft of a rotating electrical machine by means of a first bearing to form a first bearing and a longitudinal wall whose inner surface is capable of carrying a stator of a rotating electrical machine, the body comprising a cooling chamber capable of receiving a cooling fluid, the cooling chamber extending in the longitudinal wall to cool the stator and in the side wall to cool the first bearing.

[0012] Such a casing makes it possible to effectively cool the various elements of the rotating electrical machine and in particular the first bearing.

[0013] According to another aspect of the present invention, the cooling chamber extends in a spiral shape around the stator.

[0014] According to another aspect of the present invention, the cooling chamber comprises an inlet and an outlet respectively capable of allowing the entry of a cooling fluid into the cooling chamber and the exit of a cooling fluid into the cooling chamber. The inlet and the outlet may be interchanged. The cooling chamber may not comprise seals; the chamber being able to be arranged, preferably only, inside the casing and not between several separate parts, no seal is necessary, seals which can impose a direction of circulation when they are unidirectional and / or asymmetrical.

[0015] According to another aspect of the present invention, the inlet and outlet of the cooling chamber are positioned on the side wall or on the longitudinal wall of the body.

[0016] According to another aspect of the present invention, the longitudinal wall comprises an internal radial recess on the side of the side wall in which the cooling chamber extends for cooling stator coils of a rotating electrical machine.

[0017] According to another aspect of the present invention, the side wall comprises an internal axial flange configured to receive the first bearing, the cooling chamber extending into the internal axial flange to cool said first bearing.

[0018] According to another aspect of the present invention, the housing also comprises a cover comprising a side wall capable of rotatably supporting a rotor shaft of a rotating electrical machine via a second bearing to form a second bearing, the cover being configured to be fixed to the body.

[0019] According to another aspect of the present invention, the hood comprises a second cooling chamber capable of receiving a cooling fluid to cool the second bearing. The second cooling chamber can exchange fluid with the cooling chamber. The second cooling chamber can be independent of the cooling chamber.

[0020] The present invention also relates to a rotating electrical machine comprising: - a casing as described above, - a stator carried by the casing body, - a rotor mounted on a central shaft supported in rotation by means of a first bearing and a second bearing.

[0021] According to another aspect of the present invention, the stator comprises a plurality of sheets around which are wound turns of a winding wire forming coils at the longitudinal ends of the sheets.

[0022] The present invention relates to a method for manufacturing a rotating electrical machine casing as described above, comprising a step of manufacturing the body in which the cooling chamber is provided, said step of manufacturing the body being based on an additive manufacturing step.

[0023] According to another aspect of the present invention, the body is made of aluminum. The body may be made of steel. The body may be made of plastic.

[0024] Other characteristics and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and non-limiting example, and the appended drawings among which:

[0025] [Fig-1] represents a schematic perspective and sectional view of a rotating electrical machine according to an embodiment of the present invention;

[0026] [Fig.2] represents a schematic view in perspective and in transparency of the rotating electrical machine of [Fig.l];

[0027] [Fig.3] represents a schematic perspective view of the cooling chamber of the rotating electrical machine of [Fig.l];

[0028] [Fig.4] represents a flowchart of the steps of manufacturing a casing of a rotating electrical machine according to an embodiment of the present invention.

[0029] In these figures, identical elements bear the same references.

[0030] 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 features apply only to a single embodiment. Single features of different embodiments may also be combined or interchanged to provide other embodiments.

[0031] The present invention relates to a casing for a rotating electrical machine (or electric motor) as well as a rotating electric machine and a method of manufacturing such a casing.

[0032] [Fig.l] represents an exemplary embodiment of such a rotating electrical machine 1. The rotating electrical machine 1 comprises a rotor 3 mounted on a central shaft 5 guided in rotation by a first bearing formed by a first rolling bearing 7a and a second bearing formed by a second rolling bearing 7b. The first and second rolling bearings 7a, 7b are for example ball bearings.

[0033] The first bearing 7a and the second bearing 7b are arranged axially on either side of the rotor 3.

[0034] The rotating electrical machine 1 also comprises a casing 9 intended to enclose the rotor 3 and the stator 15. The casing 9 is formed by a body 11 and a cover 13 configured to be fixed on the body 11.

[0035] The body 11 of the casing 9 comprises a side wall 11a which extends mainly in a radial direction. The side wall 11a has, for example, a general disc shape. The side wall 11a is capable of supporting the central shaft 5 in rotation via the first bearing 7a. The side wall 11a comprises, for example, a housing configured to receive the first bearing 7a. The housing is, for example, formed by an internal axial collar 12 formed in the side wall 11a. The side wall 11a may also comprise a central through-hole to allow the passage of the central shaft 5.

[0036] The body 11 also comprises a longitudinal wall 11b which extends mainly in an axial direction. The longitudinal wall 11b has, for example, a generally cylindrical shape.

[0037] The body 11 is configured to receive a stator 15 of the rotating electrical machine 1, in particular the inner surface of the longitudinal wall 11b is capable of carrying the stator 15 of the rotating electrical machine 1.

[0038] The stator 15 notably comprises coils whose ends form buns 17 at the longitudinal ends of the stator 15.

[0039] The cover 13 of the casing 9 comprises a side wall 13a capable of supporting in rotation the shaft 5 of the rotor 3 of the rotating electrical machine 1 by means of the second bearing 7b to form a second bearing. The cover 13 is configured to be fixed to the body 11, for example by screws (not shown).

[0040] The body 11 of the casing 9 also comprises a cooling chamber 19. [Fig. 3] shows an example of a profile of the cooling chamber 19. The cooling chamber 19 is capable of receiving a cooling fluid such as glycolated water. The cooling chamber 19 extends in the longitudinal wall 11b of the body 11, for example in the form of a spiral, to cool the stator 15. The cooling chamber 19 also extends in the side wall 1 of the body 11, for example at the level of the internal axial collar 12 to cool the first bearing 7a.

[0041] The longitudinal wall 11b of the body 11 may comprise an internal radial recess 21 on the side of the lateral wall 11a at the level of the coils 17. The cooling chamber 19 may then extend into this internal radial recess 21 to cool the coils 17 arranged opposite this internal radial recess 21.

[0042] The cooling chamber 19 comprises an inlet 19a capable of allowing the entry of the cooling fluid into the cooling chamber 19. The inlet 19a may be provided in the side wall 11a or in the longitudinal wall 11b as shown in [Fig. 2]. The cooling chamber 19 also comprises an outlet 19b for the cooling fluid in the cooling chamber 19. The outlet 19b may be provided in the side wall 11a or in the longitudinal wall 11b as shown in [Fig. 2]. The cooling chamber 19 comprises a single inlet. The cooling chamber 19 comprises a single outlet.

[0043] The direction of circulation of the cooling fluid in the cooling chamber 19 between the inlet 19a and the outlet 19b is represented by the arrows in Figures 2 and 3.

[0044] Thus, in the case of Figures 1 to 3, the cooling chamber 19 comprises an inlet 19a formed in the longitudinal wall 11b of the body 11, in particular, in the end of the longitudinal wall 11b located on the side of the cover 13 and the second bearing 7b. The inlet 19a is oriented axially. The inlet 19a and the outlet 19b have, for example, circular sections to allow their hydraulic connection to supply and discharge conduits respectively, while the section of the rest of the cooling chamber 19 may have an oblong shape so as to minimize the radial size of the cooling chamber 19.

[0045] The cooling chamber 19 extends from the inlet 19a in the form of a spiral 19c along the longitudinal wall 11b of the body 11 to cool the stator 15 with a first turn 19d extending from the inlet 19a. The spiral 19c extends to the side wall 11a of the body 11. The spiral 19c comprises, for example, six turns adjacent to each other. By adjacent, it is meant here that the axial distance between the turns is minimal, for example less than 5 mm.The cooling chamber 19 also extends into the side wall 11a of the body 11 via a first radial duct 19e fluidly connected to a loop 19f formed in the internal axial collar 12 to cool the first bearing 7a then in a second radial duct 19g fluidly connected to the outlet 19b of the cooling chamber 19 located on the longitudinal wall 11b via a turn 19h which extends into the internal radial recess 21 to cool the buns 17 located on the side of the first bearing 7a. Alternatively, several turns can be formed in the . internal radial offset. The turn(s) arranged in the internal radial offset 21 are radially closer than the turns of the spiral 19c arranged in the longitudinal wall 11b to cool the stator 15. The loop 19f may extend over more than 50% of the periphery of the bearing, in particular over more than 75%, in particular over more than 90% of the periphery. The first radial duct 19e and the second radial duct 19g may be rectilinear ducts. The first radial duct 19e and the second radial duct 19g may be arranged in a predefined angular portion less than 60 degrees, in particular less than 45 degrees, in particular less than 30 degrees. The outlet 19b may be oriented radially. The outlet 19b may be arranged in the longitudinal wall 11b radially beyond the turns of the spiral 19c which extend into the longitudinal wall 11b.The angle between the radial ducts 19e and 19g and the turns can be a right angle but can also be made in the form of a rounded elbow so as to promote the flow of the cooling fluid. Similarly, the passages between the different diameters of the turns may be progressive (in a non-radial direction) so as to promote the flow of the cooling fluid. Bends may also be provided at the inlet 10a and outlet 19b of the cooling chamber 19 to achieve the angular changes of the cooling chamber 19 to orient said inlet 19a and outlet 19b.

[0046] However, the invention is not limited to such a cooling chamber 19 so that the position of the inlet 19a and / or the outlet 19b of the cooling chamber 19 may be different. The shape of the cooling chamber 19 may also be different and the cooling liquid may circulate so as to cool the different elements in a different order, the cooling liquid may circulate first near the first bearing 7a then near the stator 15 for example or first towards the coils 17 then towards the first bearing 7a for example.

[0047] Thus, the body 11 of the casing 9 can be made from a single part in which the cooling chamber is arranged. The body 11 is for example made by additive manufacturing. The body 11 can be made from aluminum or from a plastic material, in particular from a polymer material.

[0048] According to an embodiment not shown, the cover 13 of the casing 9 may also comprise a cooling chamber configured to receive a cooling liquid in particular to cool the second bearing 7b. The cooling chamber of the cover may be independent or fluidly connected to the cooling chamber 19 of the body 11 of the casing 9.

[0049] The present invention also relates to a method of manufacturing the casing 9 and in particular the body 11 comprising an additive manufacturing step allowing to obtain a single part to form the body 11, said single part comprising a cooling chamber 19 extending in the longitudinal wall 11b and in the side wall 11a to allow cooling of the stator 15 and the first bearing 7a.

[0050] [Fig.4] represents a flowchart of the steps of the manufacturing process and of assembling a rotating electrical machine as described above.

[0051] The first step 101 concerns the manufacture of the casing 9 and in particular of the body 11 by additive manufacturing in order to obtain a single-piece body in which the cooling chamber is arranged. The cooling chamber 19 thus obtained makes it possible to ensure sealing without requiring the use of seals and without requiring complex assembly. The cover 13 of the casing 9 can also be obtained by additive manufacturing.

[0052] The second step 102 concerns the positioning of the first bearing 7a in the housing formed by the internal axial collar 12.

[0053] The third step 103 concerns the positioning of the stator 15 against the longitudinal wall 11b in the body 11.

[0054] The fourth step 104 concerns the positioning of the central shaft 5, the rotor 3 and the second bearing 7b in the stator 15. Alternatively, the second bearing 7b can be positioned on the cover 13.

[0055] The fifth step 105 concerns the positioning and fixing of the cover 13 on the body 11 to close the casing 9.

[0056] The sixth step 106 concerns the connection of supply and discharge pipes respectively to the inlet 19a and the outlet 19b of the cooling chamber to allow the circulation of the cooling liquid.

[0057] The order of the steps of the manufacturing process may be different from the order shown in [Fig.4] and certain steps may be carried out simultaneously.

Claims

Claims

1. Casing (9) for a rotating electrical machine (1) comprising a body (11) comprising a side wall (11a) capable of supporting in rotation a rotor shaft (5) of a rotating electrical machine (1) by means of a first bearing (7a) to form a first bearing and a longitudinal wall (11b) whose inner surface is capable of carrying a stator (15) of a rotating electrical machine (1), characterized in that the body (11) comprises a cooling chamber (19) capable of receiving a cooling fluid, the cooling chamber (19) extending in the longitudinal wall (11b) to cool the stator (15) and in the side wall (11a) to cool the first bearing (7a).

2. A housing (9) according to claim 1 wherein the cooling chamber (19) extends in a spiral shape (19c) around the stator (15).

3. A housing (9) according to claim 1 or 2 wherein the cooling chamber (19) comprises an inlet (19a) and an outlet (19b) respectively capable of allowing the entry of a cooling fluid into the cooling chamber (19) and the exit of a cooling fluid into the cooling chamber (19).

4. Housing (9) according to the preceding claim in which the inlet (19a) and the outlet (19b) of the cooling chamber (19) are positioned on the side wall (11a) or on the longitudinal wall (11b) of the body (H).

5. Casing (9) according to one of the preceding claims in which the longitudinal wall (11b) comprises an internal radial recess (21) on the side of the side wall (11a) in which the cooling chamber (19) extends for cooling the stator (15) coils (17) of the rotating electrical machine (1).

6. Housing (9) according to one of the preceding claims wherein the side wall (11a) comprises an internal axial collar (12) configured to receive the first bearing (7a), the cooling chamber (19) extending into the internal axial collar (12) to cool said first bearing (7a).

7. Housing (9) according to one of the preceding claims also comprising a cover (13) comprising a side wall (13a) capable of supporting in rotation a rotor shaft (5) of an electric machine rotating (1) via a second bearing (7b) to form a second bearing, the cover (13) being configured to be fixed to the body (11).

8. Rotating electrical machine (1) comprising: - a casing (9) according to one of the preceding claims, - a stator (15) carried by the body (11) of the casing (9), - a rotor (3) mounted on a central shaft (5) supported in rotation by means of a first bearing (7a) and a second bearing (7b).

9. Rotating electrical machine (1) according to the preceding claim in which the stator (15) comprises a plurality of sheets around which are wound turns of a winding wire forming buns (17) at the longitudinal ends of the sheets.

10. Method of manufacturing a casing (9) of a rotating electrical machine (1) according to one of claims 1 to 8 comprising a step of manufacturing the body (11) in which the cooling chamber (19) is arranged, said step of manufacturing the body (11) being based on an additive manufacturing step (101).

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