Element for distributing flow within a hollow tree.

Abstract

Flow distribution element within a hollow shaft. The invention relates to a distribution element (30) intended to be fitted within a bore of a shaft so as to form, possibly in cooperation with a surface of the bore, two fluid circuits, particularly oil circuits, within that bore. The distribution element (30) comprises a positioning element (39) for the distribution element (30) within the bore, and at least one separating wall (37) for the two fluid circuits. Illustration: Fig. 4

Description

Title of the invention: Flow distribution element within a hollow tree. Technical field of the invention

[0001] The invention relates to a flux distribution element within a hollow shaft. The invention further relates to an electric motor rotor shaft comprising such a distribution element. The invention further relates to an electric motor comprising such a shaft or such a distribution element. The invention further relates to a vehicle comprising such an electric motor. Prior art

[0002] A vehicle, in particular a motor vehicle, generally includes at least one electric traction and / or propulsion motor to move such a vehicle. This is especially true of hybrid or electric vehicles.

[0003] Such an electric motor comprises a rotor which rotates close to a stator. For example, the rotor has a high, or even very high, rotational speed, for example on the order of 16,000 revolutions per minute.

[0004] Such an electric motor heats up during operation, but it must not exceed a temperature limit, for example, around 140 degrees Celsius. Indeed, beyond this temperature limit, the magnets of such an electric motor lose, at least partially, their magnetic properties, resulting in malfunctions of the electric motor.

[0005] Furthermore, such a vehicle generally includes a gearbox to adapt the rotational speed of a ground contact element, such as a wheel, to the rotational speed output from the electric motor. Such an electric motor is generally arranged, at least partially, within such a gearbox. Such a gearbox also reaches a high temperature during operation, for example, on the order of 100 degrees Celsius.

[0006] Thus, preventing such an electric motor from reaching, or even exceeding, a temperature limit, when it is arranged at least partly within such a gearbox which is itself hot, is particularly complex.

[0007] It follows that such an electric motor requires cooling in order to avoid reaching the limiting temperature causing malfunctions related to the loss of the magnetic properties of the magnets. Presentation of the invention

[0008] The present invention aims to provide a distribution element that overcomes the above drawbacks. In particular, the invention makes it possible to obtain a motor rotor electric including a shaft which provides cooling of the motor, compatible with the high speed of the rotor and ensuring cooling at each end of the rotor although the admission of a cooling fluid is only at one end of the rotor. Summary of the invention

[0009] To achieve this objective, the invention relates to a distribution element intended to be inserted within a bore of a shaft so as to form, possibly in cooperation with a surface of the bore, two fluid circuits, in particular oil circuits, the distribution element comprising: - a positioning element for the distribution element in the bore, and - at least one wall separating the two fluid circuits.

[0010] The invention further relates to a shaft for an electric motor rotor, in particular a traction and / or propulsion motor for a motor vehicle, the shaft comprising: - a central bore centered on the axis of the shaft, the central bore being intended to receive oil at an open end of the central bore, - a section of the shaft extending axially over a given length of the shaft and intended to extend substantially opposite a stator of such an electric motor, the section comprising a first part and a second part on either side of a plane passing through the axis of the shaft, the section comprising a first axial end and a second axial end, - a first hole extending from the central bore within the first part of the section and near the first axial end of the section,- a second hole extending from the central bore within the second part of the section and near the second axial end of the section, the shaft comprising a distribution element as defined previously, brought into the central bore so as to supply oil to the first hole and the second hole.

[0011] The distribution element can be shaped so as to create, in the central bore, a first oil supply chamber for the first hole and a second oil supply chamber for the second hole, the first and second chambers being able to communicate with the open end of the central bore.

[0012] The distribution element may include the second oil supply chamber, the second chamber may include a discharge orifice arranged opposite the second hole.

[0013] The second chamber may have a hollow half-cylinder shape extending into the second part of the section, the second chamber may have a bottom in the shape of a half-disc extending perpendicularly to the axis of the shaft.

[0014] The distribution element may include a hollow half-cylinder shape that can extend into the first part of the section.

[0015] The positioning element may be in contact with the central bore, in particular the positioning element may have a hollow cylinder shape of diameter equal to or substantially equal to the diameter of the central bore so as to be press-fitted and / or glued within the central bore.

[0016] The separating wall can extend substantially centered on the plane and a circular half-pad can extend radially from the separating wall in the central bore, within the second part of the section, the circular half-pad being able to be arranged between the first hole and the second hole while being distant from the first hole and the second hole.

[0017] The positioning element can be a cylindrical part with a diameter equal to or substantially equal to the diameter of a non-through end of the bore so as to fit in by force and / or to stick to the non-through end.

[0018] An axial end of the first chamber can be arranged at a defined distance from the first hole, in particular at a defined distance of twice the diameter of the first hole, and an axial end of the second chamber can be arranged at a defined distance from the second hole, in particular at a defined distance of twice the diameter of the second hole.

[0019] The invention further relates to an electric motor, in particular a traction and / or propulsion motor for a vehicle, the electric motor comprising a rotor shaft as defined above or a distribution element as defined above.

[0020] The invention further relates to a vehicle, in particular a motor vehicle, comprising a gearbox, the vehicle comprising an electric motor as defined above arranged at least partially within the gearbox. Figures

[0021] These objects, features and advantages of the present invention will be described in detail in the following description of a first and a second embodiment of a distribution element, given by way of non-limiting example, in relation to the accompanying figures, among which:

[0022] Fig. 1 is a schematic view of a motor vehicle according to one embodiment of the invention.

[0023] Fig. 2 is a cross-sectional view of an electric motor comprising a distribution element according to a first embodiment of the invention.

[0024] Fig. 3 is a front view of the distribution element according to the first embodiment of the invention.

[0025] Fig. 4 is a perspective view of the distribution element according to the first embodiment of the invention.

[0026] Fig. 5 is a cross-sectional view of an electric motor comprising a distribution element according to a second embodiment of the invention.

[0027] Fig. 6 is a perspective view of the distribution element according to the second embodiment of the invention. Detailed description

[0028] The direction in which a vehicle, particularly a motor vehicle, moves in a straight line is defined as the longitudinal direction X. By convention, the direction perpendicular to the longitudinal direction, located in a plane parallel to the ground, is called the transverse direction Y. The third direction, perpendicular to the other two, is called the vertical direction Z. Thus, a right-handed coordinate system XYZ is used in which X is the longitudinal direction in the front-to-back direction of the vehicle, i.e., directed towards the rear, Y is the transverse direction directed to the right, and Z is the vertical direction directed upwards. The forward direction corresponds to the direction in which the vehicle usually moves in the longitudinal direction and is opposite to the backward direction.

[0029] As illustrated in [Fig. 1], a vehicle, in particular a motor vehicle 1, includes a gearbox 5. The vehicle includes an electric motor 2, for example, an electric traction and / or propulsion motor for the vehicle. Advantageously, the electric motor 2 is arranged, at least partially, within the gearbox 5.

[0030] More specifically, as illustrated in Figures 2 and 5, the electric motor 2 comprises a shaft 10, a rotor 3, and a stator 4. The shaft 10 includes an axis A. The shaft 10 is the shaft of the rotor 3. In other words, the shaft 10 and the rotor 3, the rotor 3 being, for example, fixed to the shaft 10, are intended to rotate about the axis A, or substantially about the axis A, for example at a very high speed, for example on the order of 16,000 rpm. Preferably, the rotor 3 is arranged opposite the stator 4.

[0031] The shaft 10 includes a bore 20, preferably a central bore 20, that is, centered on the axis A of the shaft. The shaft 10 includes a through end 24 of the central bore 20. The bore is intended to receive a fluid at the through end 24.

[0032] The shaft 10 of the rotor 3 includes a distribution element or distributor.

[0033] A first embodiment of the distribution element 30 is illustrated in figures 2, 3 and 4.

[0034] The distribution element 30 is brought into the bore 20 of the shaft 10. The distribution element 30 then forms, possibly in cooperation with a surface 25 of the bore, two fluid circuits in this bore. By fluid, we preferably mean oil, for example lubricating and / or cooling oil.

[0035] The fluid inlet or intake is provided at the open end 24 of the shaft 10. Advantageously, the bore 20 is machined from this open end 24. A first fluid circuit Cl extends from the inlet to a first hole 21. A second fluid circuit C2 extends from the inlet 24 to a second hole 22. The first circuit Cl and the second circuit C2 are indicated at the inlet and outlet of each hole by an arrow.

[0036] More specifically, as illustrated in particular in [Fig. 4], the distribution element 30 includes a positioning element 39 for the distribution element 30 in the bore 20. For example, the positioning element 39 is in contact, or substantially in contact, with the central bore 20. Advantageously, the positioning element 39 has the shape of a hollow cylinder with a diameter equal to or substantially equal to the diameter of the central bore 20. Thus, it is easy to press-fit and / or glue the positioning element 39 into the central bore 20 of the shaft 10. Preferably, the cylindrical positioning element 39 includes a shoulder 38 intended to abut against or at the level of the open end of the shaft 10 or the inlet 24.

[0037] The distribution element 30 further includes at least one separation wall 37 of a flow C separating into two flows or circuits Cl, C2 of fluid, as illustrated in particular in [Fig.4].

[0038] The shaft 10 for the rotor 3 of the electric motor 2 further comprises a section 15, or cylindrical portion, of the shaft 10 extending axially over a given length L15 of the shaft 10 illustrated in Figures 2 and 5. The section 15 is intended to extend, or substantially extend, opposite the stator 4 of the electric motor 2. More precisely, the section 15 comprises a first part 16 and a second part 17 on either side of a plane P passing through the axis A of the shaft 10. In other words, the section 15 is divided, cut, separated in two, in a notional manner, by the plane P so as to obtain the first part 16 (portion of the shaft 10 extending below the axis line A in Figures 2 and 5) and over the axial length L15, the plane P extending perpendicularly (in this view) and the second part 17 (portion of the tree 10 extending above the axis line A in figures 2 and 5 and over the axial length L15, the plane P extending perpendicularly to this view).

[0039] Section 15 comprises a first axial end 11 and a second axial end 12 illustrated in dotted lines in Figures 2 and 5.

[0040] The shaft 10 includes the first hole 21. The first hole 21 extends, for example, radially from the central bore 20, within the first part 16 of the section 15, and near the first axial end 11 of the section 15. Preferably, as illustrated in Figures 2 and 5, the first hole 21 is circular and / or the axis of the first hole 21 extends perpendicularly to the plane P. The first hole 21 extends from the central bore 20 to an external surface 18 of the first part 16 of the section 15. Alternatively, several holes, radial or otherwise, are provided so as to extend from the central bore 20 to the external surface 18 of the first part 16 of the section 15.

[0041] The shaft 10 includes the second hole 22. The second hole 22 extends, for example, radially from the central bore 20, within the second part 17 of the section 15, and near the second axial end 12 of the section 15. Preferably, as illustrated in Figures 2 and 5, the second hole 22 is circular and / or the axis of the second hole 22 extends perpendicularly to the plane P. The second hole 22 extends from the central bore 20 to an external surface 19 of the second part 17 of the section 15. Alternatively, several holes, radial or otherwise, are provided so as to extend from the central bore 20 to the external surface 19 of the second part 17 of the section 15.

[0042] The shaft 10 includes the distribution element which is attached, glued, and fitted within the central bore 20. Thus, the fluid admitted at the open end 24 of the bore 20 communicates with, and supplies, the first hole 21 and the second hole 22.

[0043] As illustrated in [Fig.2], in the first embodiment, the distribution element 30 is shaped so as to create, in the central bore, a first chamber 31 for supplying the first hole 21 and a second chamber 32 for supplying the second hole 22. The first and second chambers 31, 32 are communicating with the open end 24 of the central bore 20.

[0044] More specifically, in the first embodiment illustrated in Figures 3 and 4, it is the distribution element 30 that creates the second supply chamber 32. The second chamber 32 then has the shape of a hollow half-cylinder 35 extending into the second part 17 of the section 15 of the shaft 10 once the element 30 is arranged in the bore 20. The second chamber 32 then has a bottom 33 in the shape of a half-disc extending perpendicularly to the axis A so as to close, plug, or seal the hollow half-cylinder 35. The second chamber 32 includes a discharge hole or orifice 34 for the fluid, for example circular, arranged opposite or at least partially opposite the second hole 22 once the distribution element 30 is inserted into the bore 20 of the shaft 10.

[0045] The distribution element 30 of the first embodiment comprises a hollow half-cylinder shape 36. The hollow half-cylinder 36 extends into the first part 16 of the section 15 once the element 30 is arranged in the bore 20.

[0046] Preferably, the hollow half-cylinder 35, closed by the bottom 33, and the hollow half-cylinder 36 form a cylinder having an external skin or surface with a diameter substantially equal to, and preferably slightly smaller than, the diameter of the bore 20. In this case, the external surface of the two half-cylinders 35 and 36 form the positioning element 39, facilitating the attachment of the distribution element 30 within the bore 20. The separating wall 37 extends on either side of the fictitious plane P separating the first part 16 from the second part 17 of the section 15, preferably centered with respect to plane P. The separating wall 37 extends in the direction of the inlet 24 so as to divide the flow of fluid C arriving at the inlet into two flows C1 and C2. Advantageously, as illustrated in [Fig.2], the separating wall 37 does not extend to the level of the shoulder 38.Indeed, the separating wall 37 stops at a distance L24 from the inlet 24, i.e., from the bore orifice 20 or from the shoulder 38. Thus, the flow C arriving at the inlet 24 is not divided immediately upon entering the distribution element 30 but after traveling the distance L24 within the distribution element 30. For example, the distance L24 is equal to at least the inside diameter of the tubular part of the element 30 receiving the fluid, or even twice this inside diameter, so as to obtain laminar flow instead of turbulent flow.

[0047] Advantageously, as illustrated in [Fig.2], the axial end of the first chamber 31 corresponds to the non-through end 23 of the bore 20. Preferably, the end 23 is provided at a defined distance D from the first hole 21. For example, the defined distance D is twice the diameter of the first hole 21, or at least twice the diameter of the first hole 21.

[0048] Advantageously, as illustrated in [Fig. 2], the axial end of the second chamber 32 is obtained by the bottom 33. The bottom 33 is preferably arranged at a defined distance D from the second hole 22. For example, the defined distance D is twice the diameter of the second hole 22, or at least twice the diameter of the second hole 22. The bottom 33 is arranged, along the axial direction, after the second hole 22, that is to say between the non-opening end 23 and the second hole 22 so as to allow the fluid in the second chamber 32 to access the inside of the second hole 22.

[0049] In this first embodiment, the distribution element is therefore a part comprising a cylindrical portion which allows for a uniform distribution of the oil on its internal surface by centrifugal force at the inlet 24. On the side of the first part 16 of the section 15, the element 30 extends axially with the open semi-cylindrical portion 36 which allows oil to pass towards the bottom 23 of the central bore 20 of the rotor shaft. On the side of the second part 17 of the section 15, the element 30 extends axially with the semi-cylindrical chamber 32 comprising the radial oil discharge orifice 34 located opposite the second hole 22 made in the rotor shaft on the oil inlet side.

[0050] Note that the shoulder 38 ensures axial positioning of the distribution element 30 relative to the central bore 20. Preferably, the contact between the shoulder 38 of the element 30 and an end or a shoulder of the central bore 20 of the shaft 10 ensures that the orifice 34 of the hollow half-cylinder 35 is at the level, along axis A, of the second hole 22 provided in the shaft.

[0051] According to a second embodiment illustrated in figures 5 and 6, the distribution element 40 is also shaped so as to create, in the central bore, a first chamber 41 for feeding the first hole 21 and a second chamber 42 for feeding the second hole 22. The first and second chambers each communicate with the through end 24 of the central bore 20.

[0052] In this second embodiment, the distribution element 40 includes a positioning element 49 for the distribution element 40 in the bore 20. For example, the positioning element 49 is a cylindrical part with a diameter equal to, or substantially equal to, the diameter of the non-through end 23 of the bore 20. Thus, the distribution element 40 can be press-fitted and / or glued to the non-through end 23. In addition, the distribution element 40 includes at least one separating wall 47 of the two fluid circuits.

[0053] More specifically, the separating wall 47 preferably extends substantially centered on the fictitious plane P separating the first part 16 from the second part 17 of the section 15. Preferably, the separating wall 47, for example of the plate type, comes into contact, or is substantially in contact, with the wall 25 of the bore 20. In the case of a cylindrical positioning element 49 in the bore, preferably the separating wall has a clearance relative to the bore 20 so as not to hinder the assembly of the positioning element at the bottom 23 of the bore 20. For example, the separating wall 47 comprises two edges 46 intended to come into contact, or is substantially in contact, with the bore 20. For example, the section perpendicular to the axis A of each edge 46 is curved so as to follow the circular section of the central bore 20. opposite each edge.The curvature of each edge 46 then has an axis radius A of length just less than the radius of the bore 20 at that level.

[0054] The distribution element 40 further comprises a circular half-pad 48. The circular half-pad or half-plate 48 extends radially from the separating wall 47. Thus, the circular half-pad 48 extends to the central bore 20, or substantially to the bore 20 so as not to hinder the assembly of the element 40 within the bore 20. The circular half-pad 48 extends into the second part 17 of the section 15. The circular half-pad 48 therefore creates an axial bottom, or substantially an axial bottom, for the second chamber 42.

[0055] Thanks to the separating wall 47, in particular centered on the plane P, and the half-pad 48, the distribution element 40 creates in the bore 20 the first chamber 41 within the first part 16 of the section 15 of the shaft 10 and the second chamber 42 within the second part 17 of the section 15 of the shaft 10.

[0056] More specifically, the first chamber 41 has a substantially half-cylinder shape extending from the disc or cylinder-type positioning element 49 to one end 45 of the intake-side partition wall 47. The wall or surface 25 of the bore 20 on the side of the first part 16 of the section contributes to creating the first chamber 4L

[0057] The second chamber 42 also has a substantially semi-cylindrical shape extending from the half-pad 48 to the end 45 of the separating wall 47 on the intake side. The wall or surface 25 of the bore 20 on the side of the second part 17 of the section contributes to creating the second chamber 42.

[0058] Advantageously, as illustrated in [Fig. 5], the separating wall 47 does not extend to the open end 24 of the shaft 10. Indeed, the separating wall 47 stops at a distance L24 from the inlet 24, i.e., from the orifice of the bore 20. Thus, the flow C arriving at the inlet 24 is not divided upon entering the bore 20 but after traveling the distance L24 in the central bore 20. For example, the distance L24 is equal to at least the diameter of the bore 20, or even to twice this diameter, so as to obtain a laminar flow instead of a turbulent one.

[0059] Note that the circular half-pad 48 is arranged, positioned, according to the direction of the axis A, between the first hole 21 and the second hole 22. In addition, the circular half-pad 48 is axially distant from the first hole 21 and the second hole 22.

[0060] Advantageously, as illustrated in [Fig.5], the axial end of the first chamber 41, for example created by the positioning element 49, is arranged at a defined distance D from the first hole 21. For example, the defined distance D is twice the diameter of the first hole 21, or at least twice the diameter of the first hole 21.

[0061] Advantageously, as illustrated in [Fig. 5], the axial end of the second chamber 42, created by the half-pellet 48, is arranged at a defined distance D from the second hole 22. For example, the defined distance D is twice the diameter of the second hole 22, or at least twice the diameter of the second hole 22. The half-pad 48 is arranged behind the second hole 22 in the direction of the non-through end 23 of the bore.

[0062] Note that the positioning element 49 ensures axial positioning of the distribution element 40 relative to the central bore 20. Preferably, the contact between the element 49 of the element 40 and the bottom of the end 23 of the central bore 20 of the shaft 10 ensures axial positioning, i.e. along the axis A, of the distribution element 40 within the bore 20.

[0063] Alternatively, according to an unillustrated variant of the second embodiment, the separating wall comprises two edges that come into contact with the central bore of the shaft and ensure positioning relative to the bore, such that the distribution element may be without a cylindrical pad-type positioning element. In this case, the end 23 of the bore comes into contact with the separating wall, which forms the bottom of the first chamber.

[0064] Alternatively, according to an unillustrated variant of the second embodiment, the distribution element is devoid of a half-pad 48. For example, the distribution element comprises only a separating plate 47 suitable for being positioned centered on the plane P and coming into contact with the end 23 of the bore 20.

[0065] For example, the seal for the oil flow C on the intake side 24 between a fixed housing and the rotating shaft end 20 is achieved via radial grooves formed on the shaft and a smooth surface of a bore in the housing. In this case, the fluid, preferably oil, creates fluid "seals" in the grooves, similar to O-rings. This eliminates the need for lip seals, which generate friction and reduce the efficiency of the electric motor.

[0066] For example, the distribution element 30; 40 of the flux is obtained from plastic material, such a material being resistant for example up to 200 degrees C. Alternatively, the distribution element is obtained from metallic material, for example by sintering.

[0067] As illustrated in Figures 2 and 5, the oil flow C, preferably from a pump, particularly a pump dedicated to lubricating the gearbox if applicable, is admitted at the inlet 24, i.e., at the open end of the shaft 10. As a reminder, the oil flow C preferably originates from a fixed housing and passes through the inlet 24 into the rotating shaft 20, particularly at high speed. As mentioned previously, the oil flow first travels a distance L24 (either within a tubular portion of the distribution element 30 in the first embodiment, or directly within the bore 20 in the second embodiment). The distance L24 helps to mitigate any potential turbulence in the oil flow related to the passage from a fixed part, the housing, to a moving part rotation, shaft 10. Thus, after this distance L24, the oil flows, or flows substantially in laminar flow, or at least is not turbulent. Thus, the separating wall 37; 47 is placed at this point so as to divide the oil flow C into two flows Cl, C2. The Cl flow joins the first chamber 31; 41 and the C2 flow joins the second chamber 32; 42. In the case of a separating wall dividing the section S20 of the bore (second embodiment - [Fig. 5]) or the section at the shoulder 38 (first embodiment - [Fig. 2]) into two straight sections SI, S2 of equal area, each substantially in the shape of a semicircle, the oil flow C is substantially divided equally into two. Thus, once the oil flow is continuous, in the case of the area of ​​holes 21, 22 identical or substantially identical, the flow Cl exiting the first hole 21 and the flow C2 exiting the second hole 22 are identical or substantially identical.

[0068] The distance D between the bottom of the first chamber and the first hole and between the bottom of the second chamber and the second hole makes it possible to attenuate, or even eliminate, the turbulence in the flow of the oil generated by the presence of these cavity bottoms.

[0069] Alternatively, one hole may have a larger cross-section than the other hole, for example, if more cooling is required on one side of the rotor and / or stator. Alternatively, or additionally, if it is desired to increase the oil flow on one side, the cross-section of the distribution element can be used to make the cross-sections of the first and second chambers unequal. In other words, the geometry of the distribution element can be adapted, modified, to calibrate each flow Cl, C2, for example, 70 percent at the bottom (flow Cl) and 30 percent at the inlet (flow C2), or vice versa. Alternatively, or additionally, several first holes (radial or otherwise) are arranged in the first part 16 of the section 15 from the bore 20 and / or several second holes (radial or otherwise) are arranged in the second part 17 of the section 15 from the bore 20.In this case, for the first embodiment, as many corresponding orifices 34 are provided in the second chamber 32 so as to be opposite the second holes.

[0070] Regardless of the embodiment, an angular positioning means (not shown) is provided within the central bore and / or on the distribution element so as to angularly orient the distribution element relative to the bore around axis A. This prevents any subsequent angular misalignment between the distribution element and the central bore.

[0071] For example, an axial groove is formed within the bore and a projection, possibly of the lug type, extends radially outwards from the distribution element. In the first embodiment, for example, one of the hollow half-cylinders 35, 36 includes the projection. In the second embodiment, for example the positioning element 49 includes the angular positioning protrusion, and / or at least one edge 46 of the separating wall 47 includes the positioning protrusion, and / or the circular half-pad 48 includes the positioning protrusion.

[0072] Indeed, each hole in the shaft must be matched with its corresponding chamber, possibly with an opening in a corresponding chamber in the distribution element. Alternatively or additionally, a means of holding the distribution element in position, for example by welding and / or press fitting and / or adhesive, is provided to angularly secure it within the bore. Thus, the holding means can also serve as an angular positioning means, which simplifies the manufacture of the shaft and / or the distribution element.

[0073] Thanks to the solution, the oil flows through holes 21 and 22 and is consequently projected on each side of the rotor 3 and stator 4 by centrifugal force. The diffusion of this oil on both sides of the rotor, and / or rotor stacks, and / or stator, contributes to the efficient cooling of the electric motor 2. As a reminder, the rotor can rotate at a speed of approximately 16,000 revolutions per minute.

[0074] Thanks to this solution, the electric motor does not reach the limiting temperature of approximately 140°C. Thus, the magnets retain their magnetic properties, remain unaltered, and the motor operates perfectly. Furthermore, it prevents only one side from being adequately cooled. As mentioned previously, the solution preferably aims to create two equal fluxes on either side of the rotor / stator assembly so as to cool both sides equally. This prevents one side from being less cooled and the magnets arranged there from causing malfunctions in the electric motor.

[0075] The solution is compatible with an electric motor integrated within a gearbox. Indeed, although the gearbox has a temperature of around 100 degrees C, for example, cooling via the holes makes it possible to keep each lateral face of the electric motor below the critical temperature, for example around 140 degrees C.

[0076] In summary, the solution consists of placing a physical element at the center of the rotor shaft to separate the oil flow entering the shaft and its centrifugation into two distinct flows. As seen previously, preferably, a single hole, for example radial, is provided in the rotor shaft through which the first half of the flow is directed outwards from the shaft, and one or more holes at the other end of the shaft to direct the second half of the oil flow to the other side of the rotor.

[0077] In other words, the invention relates to a two-stream oil flow separator for cooling an electric motor. Although the oil inlet is arranged on only one side On the shaft, the oil diffusion hole closest to the intake does not offer a higher flow rate than the hole furthest from the intake. Furthermore, the solution allows for oil flow rates through the holes that are independent of rotational speed.

[0078] The solution thus makes it possible to cool the electric motor with oil injected into the bore 20 of the shaft 10 of the rotor 3. Although the oil is introduced into the inlet 24 at the bore 20, i.e., at the center of the rotor, the oil is projected by centrifugal force into the stator 4, thereby removing heat from the hot parts, particularly the rotor and stator. Thus, the solution is suitable for cooling the heat flux produced by the symmetrical losses of the electric motor.

[0079] The solution allows, if desired, a distribution of the oil flow arriving in the bore into two equal flows so as to optimize cooling over the entire range of engine rotation speeds.

[0080] Optionally, the solution allows for increasing the diameters of holes 21 and 22, if necessary, since their diameter has little or no influence on the oil distribution. Drilling or machining larger diameter holes is advantageous because it is easier and therefore less expensive, thus contributing to cost savings.

[0081] Although two embodiments have been described, other forms of the distribution element or flow separator may be suitable for creating two separate chambers within the central bore so that each chamber supplies oil to at least one hole provided on the intake side and at least one other hole provided at the other end of the shaft.

[0082] The solution is suitable for cooling any electric motor equipped with an oil inlet. The solution is particularly well-suited for cooling an electric motor located, at least partially, within a gearbox, especially in a vehicle. Indeed, although the gearbox reaches a temperature of around 100°C, for example, the cooling provided by the solution allows the electric motor, whose rotation can be very high, to be cooled so as to prevent it from reaching a critical temperature of around 140°C. As a reminder, such a temperature causes a loss of magnetic properties in the magnets, which leads to malfunctions in the electric motor.

[0083] The solution therefore provides efficient cooling for the electric motor, compatible with its integration within a gearbox. Furthermore, the distribution element is easy to manufacture and integrate within the shaft, in which a bore has been machined, for example. Thus, the solution makes it possible to obtain an electric motor rotor that provides cooling at each end of the rotor, for example with two equal or even equal oil flows.

[0084] In remark, the solution therefore achieves the desired objective of obtaining an electric motor rotor comprising a shaft which provides motor cooling, compatible with the high speed of the rotor and ensuring cooling at each end of the rotor although the admission of the cooling fluid is only at one end of the rotor, and has the advantage of being able to be adapted to all types of electric motors benefiting from a fluid admission for its lubrication and / or cooling.

Claims

Demands

1. Distribution element (30; 40) intended to be brought into a bore (20) of a shaft (10) so as to form, possibly in cooperation with a surface of the bore, in this bore two fluid circuits, in particular oil, the distribution element (30; 40) comprising: - a positioning element (39; 49) of the distribution element (30; 40) in the bore (20), and - at least one separating plate (37; 47) of the two fluid circuits, - a bottom (33; 48) in the form of a half disk or half circular disc.

2. Shaft (10) for a rotor (3) of an electric motor (2), in particular a traction and / or propulsion motor of a motor vehicle (1), the shaft (10) comprising: - a central bore (20) centered on the axis (A) of the shaft (10), the central bore (20) being intended to receive oil at an open end (24) of the central bore (20), - a section (15) of the shaft (10) extending axially over a given length (L15) of the shaft (10) and being intended to extend substantially opposite a stator (4) of such an electric motor (2), the section (15) comprising a first part (16) and a second part (17) on either side of a plane (P) passing through the axis (A) of the shaft (10), the section (15) comprising a first axial end (11) and a second axial end (12),- a first hole (21) extending from the central bore (20) within the first part (16) of the section (15) and near the first axial end (11) of the section (15), - a second hole (22) extending from the central bore (20) within the second part (17) of the section (15) and near the second axial end (12) of the section (15), the shaft (10) comprising a distribution element (30; 40) according to claim 1 brought within the central bore (20) so as to supply oil to the first hole (21) and the second hole (22).

3. Shaft (10) according to the preceding claim, characterized in that the distribution element (30; 40) is shaped so as to create, in the central bore, a first chamber (31; 41) for supplying oil to the first hole (21) and a second chamber (32; 42) for supplying oil to the second hole (22), the first and second chambers being communicative with the open end (24) of the central bore (20).

4. Shaft (10) according to the preceding claim, characterized in that the distribution element (30) comprises the second oil supply chamber (32), the second chamber (32) comprising a discharge orifice (34) arranged opposite the second hole (22).

5. Shaft (10) according to the preceding claim, characterized in that the second chamber (32) has a hollow half-cylinder shape (35) extending into the second part (17) of the section (15), the second chamber (32) having the bottom (33) in the shape of a half-disc extending perpendicularly to the axis (A) of the shaft (10).

6. Shaft (10) according to claims 4 and 5, characterized in that the distribution element (30) comprises a hollow half-cylinder shape (36) extending into the first part (16) of the section (15).

7. Shaft (10) according to any one of claims 2 to 6, characterized in that the positioning element (39) is in contact with the central bore (20), in particular the positioning element (39) has a hollow cylindrical shape of diameter equal to or substantially equal to the diameter of the central bore (20) so as to be press-fitted and / or glued within the central bore (20).

8. Shaft (10) according to any one of claims 2 or 3, characterized in that the separating plate (47) extends substantially centered on the plane (P) and in that the bottom (48) in the form of a circular half-pad extends radially from the separating plate (47) in the central bore (20), within the second part (17) of the section (15), the bottom (48) being arranged between the first hole (21) and the second hole (22) and being distant from the first hole (21) and the second hole (22).

9. Shaft (10) according to the preceding claim, characterized in that the positioning element (49) is a cylindrical part of diameter equal to or substantially equal to the diameter of a non-through end (23) of the bore (20) so as to fit by force and / or to stick to the non-through end (23).

10. Shaft (10) according to any one of claims 2, or 4 to 9, in combination with claim 3, characterized in that an axial end of the first chamber (31; 41) is arranged at a defined distance (D) from the first hole (21), in particular at a defined distance (D) of twice the diameter of the first hole (21), and in that an axial end of the second chamber (32; 42) is arranged at a defined distance (D) from the second hole (22), in particular at a defined distance (D) of twice the diameter of the second hole (22).

11. Electric motor (2), in particular traction and / or propulsion motor for vehicle, characterized in that the electric motor (2) comprises a rotor shaft (10) according to any one of claims 2 to 10 or a distribution element (30; 40) according to claim 1.

12. Vehicle, in particular motor vehicle (1), comprising a gearbox (5), characterized in that the vehicle comprises an electric motor (2) according to the preceding claim arranged at least partially within the gearbox (5).

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