Rotating electric machine provided with a bearing made of two overmolded parts

Abstract

The invention relates generally to a rotating electrical machine, in particular for a motor vehicle, comprising a bearing (15) comprising a recess (17) for accommodating a shaft bearing for guiding the rotation of a shaft, characterised in that the bearing (15) comprises: a first part (15.1) made of a first material, comprising: a recess (17) for accommodating the shaft bearing; an interface (51) for assembling a bearing (50) of a pinion (49) outside the rotating electrical machine; and a second part (15.2) made of a second material, comprising: a transverse wall (53); a skirt (54) extending from the transverse wall (53) and at least partially surrounding a stator (11); the second part (15.2) being overmoulded onto the first part (15.1) to form a solid bearing (15).

Description

Technical Field

[0001] The invention relates to a rotating electrical machine provided with a support made of two overmoulded parts. The invention has a particularly advantageous, but not exclusive, application in high-power reversible electrical machines which can be operated in alternator mode and in motor mode coupled to a retarder element. Background Art

[0002] The rotating electric machine comprises a stator and a rotor fixed on a shaft in a known manner. The stator is assembled in a housing, which is configured to rotatably support the shaft on a support via a bearing.

[0003] The rotor comprises a body formed by a stack of metal sheets held in a group by a suitable fixing system. The rotor comprises poles formed, for example, by permanent magnets housed in cavities provided in the magnetic mass of the rotor. Alternatively, in a so-called "salient" pole configuration, the poles are formed by coils wound on the arms of the rotor.

[0004] In addition, the stator comprises a body consisting of a stack of thin metal plates forming a crown, the inner surface of which is provided with recesses open towards the inside to accommodate the windings. The windings are obtained, for example, from a continuous wire covered with enamel or from conductive elements in the form of pins connected to each other by welding. The windings comprise phase windings connected in the form of a star or a triangle, the outputs of which are connected to an electronic control module.

[0005] In certain types of motor vehicle traction chains ensuring the transmission of the mechanical power of the heat engine to the wheels of the vehicle, a high-power reversible rotary electric machine can be coupled to a reducer element. The reducer element can be in the form of a gearbox of the vehicle or in the form of a reducer mounted on the wheel train of the vehicle and mechanically connected to the rotary electric machine.

[0006] In order to ensure the coupling between the motor and the reducer element, the pinion supported by the shaft of the motor engages with the pinion supported by the reducer via an intermediate pinion mounted on the bracket of the motor. To this end, the bracket includes an interface for mounting the bearing of the intermediate pinion. Mechanical simulations of the system's operation have shown the presence of axial, radial and tangential forces that are difficult for the bracket to withstand, especially when the bracket is made entirely of aluminum, which is not a strong material. Summary of the invention

[0007] The object of the present invention is to effectively eliminate this drawback by proposing a rotating electrical machine, in particular for a motor vehicle, comprising:

[0008] -axis;

[0009] - a rotor mounted on a shaft;

[0010] - a stator, particularly surrounding the rotor;

[0011] a support, comprising a receptacle for receiving a shaft bearing, which ensures rotational guidance of the shaft,

[0012] Characterized in that the bracket comprises:

[0013] - A first part made of a first material, comprising:

[0014] - a receiving portion for receiving a shaft bearing;

[0015] - an interface for mounting the bearing of the pinion outside the rotating electrical machine; and

[0016] - A second part made of a second material, comprising:

[0017] - transverse walls;

[0018] - a skirt obtained from the transverse wall, which at least partially surrounds the stator;

[0019] - Overmolding the second part over the first part to form a strong bracket.

[0020] The invention thus makes it possible to mechanically reinforce the region of the bracket comprising the support surface for the pinion of the shaft of the electric motor and the bearing of the pinion engaging the reducer element, so as to be able to withstand the forces experienced during assembly.

[0021] According to an embodiment, the first portion is made of a stronger material than the material of the second portion.

[0022] According to an embodiment, the first part is made of steel.

[0023] According to an embodiment, the second part is made of aluminum.

[0024] According to one embodiment, the assembly interface extends protrudingly in order to be inserted into the interior of the inner ring of the bearing of the corresponding pinion.

[0025] According to one embodiment, the receptacle for receiving the shaft bearing of the first part is configured to receive an outer ring of the shaft bearing.

[0026] According to one embodiment, the first portion comprises, on its rear face, an alternation of ribs and recesses.

[0027] According to an embodiment, the transverse wall is provided with openings for the passage of the ends of the phases of the stator.

[0028] The invention also relates to an assembly comprising a rotating electrical machine as defined previously.

[0029] According to an embodiment, the retarder element is a motor vehicle gearbox.

[0030] According to one embodiment, the reducer element is a reducer which is mounted on a wheel train of the vehicle and is coupled to the rotating electrical machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The invention will be better understood by reading the following description and examining the accompanying drawings, which are provided purely by way of illustration of the invention and are in no way limiting.

[0032] Figure 1 is a perspective view showing a coupling between a reducer element and a rotating electric machine according to the present invention;

[0033] Figure 2 is a longitudinal sectional view of a rotating electrical machine according to the present invention;

[0034] Figure 3 is a perspective view of a front bracket in two parts of a rotating electrical machine according to the present invention;

[0035] Figure 4a and 4b is a perspective view of a first portion forming a front bracket of a rotating electrical machine according to the present invention;

[0036] Figure 5 is a perspective view of a second portion forming the front bracket of the rotating electrical machine according to the present invention.

[0037] Identical, similar or similar elements are provided with the same reference signs in the various figures. DETAILED DESCRIPTION

[0038] In the following description, the front-to-back orientation is considered Figure 2 Thus, a "front" element refers to an element located on one side of the front bearing 19, and a "rear" element refers to an element located on the opposite side.

[0039] Figure 1 and 2 A rotating electrical machine 10 is shown, comprising a multiphase stator 11 surrounding a rotor 12 mounted on a shaft 13, the axis X corresponding to the axis of the electrical machine 10. The stator 11 surrounds the rotor 12, with an air gap between the inner periphery of the stator 11 and the outer periphery of the rotor 12. The stator 11 is mounted in a housing 14 comprising a front support 15 and a rear support 16. The front support 15 and the rear support 16 respectively comprise housings 17, 18 for accommodating respective bearings 19, 20, which ensure the rotational guidance of the shaft 13.

[0040] The electric machine 10 is designed to be coupled to a reducer element 22. The reducer element 22 may be in the form of a motor vehicle gearbox or reducer which is fitted to the wheel train of the vehicle and coupled to the rotating electric machine 10.

[0041] The electric machine 10 can be operated in alternator mode, in particular to supply energy to the battery and the onboard network of the vehicle, and in motor mode to ensure starting of the thermal engine of the vehicle and, if applicable, also to participate in traction of the vehicle alone or in combination with the thermal engine. The power of the electric machine can be, for example, between 15 kW and 50 kW.

[0042] More specifically, if Figure 2 As shown, the rotor 12 comprises a body 24 in the form of a set of metal plates. Permanent magnets 25 are implanted in cavities 26 in the body 24. Depending on the application and the power required by the motor 10, the magnets 25 may be made of rare earth or ferrite.

[0043] Furthermore, the rotor 12 comprises two flanges 28, 29, each placed against an axial end face of the rotor 12. These flanges 28, 29 ensure axial retention of the magnets 25 and also serve to balance the rotor 12.

[0044] Furthermore, the stator 11 comprises a body 31 formed of a set of metal plates and a winding 32. The body 31 is formed of a stack of metal plate sheets which are held in a group by a suitable fixing system such as rivets.

[0045] The stator body 11 is provided with teeth defining recesses for fitting the winding 32. The winding 32 comprises a phase winding assembly which passes through the recesses and forms a bun protruding from both sides of the stator body 11. In this case, the winding 32 is obtained by conductive elements in the form of pins, which are connected to each other, for example, by welding. The winding 32 comprises a phase winding of the double three-phase type connected in star and / or delta form. The phase output is designed to be connected to an electronic control module 34.

[0046] The electronic control module 34 comprises a heat sink 35 on which power modules 36 are fixed, for example by screws. These power modules 36 comprise switches in a known manner, for example in the form of transistors of the MOS type, making it possible to ensure the phase control of the rotary electric machine 10 in motor mode or alternator mode. The switching of these transistors is controlled by a control unit. The electronic control module 34 is mounted via the heat sink 35 against the rear face of the transverse wall of the rear support 16.

[0047] Advantageously, the electric machine 10 comprises a cooling circuit 38 with an input 39 for a cooling liquid (for example a water or oil based liquid) and an output 40. The cooling circuit 38 has a cooling chamber 41 provided in the bulk of the radiator 35 and a cooling chamber 42 surrounding the stator 11.

[0048] The cooling chamber 42 may be defined by the outer periphery of the annular wall of the front bracket 15 and the inner periphery of the annular wall of the rear bracket 16. The cooling chamber 42 is closed at its axial ends by two seals 46 of the O-ring type. The stator 11 is shrink-fitted inside the front bracket 15 so as to establish close contact between the outer periphery of the stator body 31 and the inner periphery of the side wall of the front bracket 15.

[0049] As a variation, Figure 1 As shown, the stator 11 is assembled by fixing the tie rods to be clamped between the front bracket 15 and the rear bracket 16. The exposed outer periphery of the stator body 31 can directly contact the cooling liquid.

[0050] like Figure 1 As shown, in order to ensure the coupling between the motor 10 and the reducer element 22, a pinion 47 supported by the shaft of the motor 10 engages with a pinion 48 supported by the reducer element 22 via an intermediate pinion 49 mounted on the front bracket 15. To this end, the front bracket 15 includes an interface 51 for mounting a bearing 50 of the intermediate pinion 49 outside the motor 10.

[0051] like Figure 3 As shown, the front bracket 15 is formed by a first part 15.1 and a second part 15.2, which is overmolded on the first part 15.1 to form the bracket 15. The first part 15.1 is advantageously made of a stronger material than the material of the second part 15.2. According to a preferred embodiment, the first part 15.1 is made of steel and the second part 15.2 is made of aluminum.

[0052] More specifically, if Figure 4a and 4b As shown, the first part 15 . 1 comprises a receptacle 17 for receiving the shaft bearing 19 and an interface 51 for mounting a bearing 50 of the intermediate pinion 49 .

[0053] In this embodiment, the housing 17 for accommodating the first part 15.1 is configured to accommodate the outer ring of the shaft bearing 19. The assembly interface 51 extends protrudingly so as to be inserted into the interior of the inner ring of the bearing 50 of the intermediate pinion 49. As a variant, the assembly interface 51 may include a housing for accommodating the outer ring of the bearing 50 of the intermediate pinion 49.

[0054] The assembly interface 51 is radially offset relative to the housing 17 to accommodate the bearing. The axis X1 of the housing 17 corresponding to the axis of the bracket 15 is parallel to the axis X2 of the assembly interface 51. The axis X1 is designed to be combined with the axis X of the rotating electrical machine 10.

[0055] like Figure 5As shown, the second part 15.2 comprises a transverse wall 53 and a skirt 54 obtained from the transverse wall 53, the skirt 54 at least partially surrounding the stator 11. The transverse wall 53 may be provided with openings 55 for the passage of the ends of the phases of the stator. The skirt 54 comprises radially protruding ears 56 provided with openings for the passage of the fixing units.

[0056] like Figure 4b As shown, the first part 15.1 preferably comprises, on its back face, an alternation of ribs 57 and recesses 58. These ribs 57 and these recesses 58 are placed around the housing 17 for housing the bearing 19. These forms are intended to improve the mechanical connection between the first part 15.1 and the second part 15.2 of the bracket 15 by maximizing the contact surface between these two parts 15.1, 15.2.

[0057] It should be understood that the above description is provided by way of example only and does not limit the scope of the present invention, and that replacing different elements with any other equivalent means would not constitute a departure from the present invention.

[0058] Furthermore, different features, variants and / or embodiments of the present invention may be associated with each other according to different combinations, as long as they are not incompatible or mutually exclusive.

Claims

1. A rotating electrical machine (10) for a motor vehicle, comprising: - shaft (13); - a rotor (12) mounted on a shaft (13); - a stator (11) surrounding a rotor (12); a support (15) comprising a receptacle (17) for receiving a shaft bearing (19) which ensures rotational guidance of the shaft (13), Characterized in that the bracket (15) comprises: - A first part (15.1) made of a first material, comprising: - a receiving portion (17) for receiving a shaft bearing (19); - an interface (51) for mounting the bearing (50) of the pinion (49) outside the rotating electrical machine (10); and - a second part (15.2) made of a second material, comprising: - transverse wall (53); - a skirt (54) obtained from the transverse wall (53) which at least partially surrounds the stator (11); - Overmolding the second part (15.2) onto the first part (15.1) to form a solid support (15).

2. The rotating electrical machine according to claim 1, characterized in that: The first part (15.1) is made of a stronger material than the material of the second part (15.2).

3. The rotating electrical machine according to claim 1 or 2, characterized in that: The first part (15.1) is made of steel.

4. The rotating electrical machine according to claim 1 or 2, characterized in that: The second part (15.2) is made of aluminum.

5. The rotating electrical machine according to claim 1 or 2, characterized in that: The interface (51) extends protrudingly so as to be inserted into the interior of the inner ring of the bearing (50) of the corresponding pinion (49).

6. The rotating electrical machine according to claim 1 or 2, characterized in that: The receiving portion (17) for receiving the shaft bearing (19) of the first part (15.1) is designed to receive the outer ring of the shaft bearing (19).

7. The rotating electrical machine according to claim 1 or 2, characterized in that: The first portion (15.1) comprises an alternation of ribs (57) and recesses (58) on its rear side.

8. The rotating electrical machine according to claim 1 or 2, characterized in that: The transverse wall (53) is provided with openings (55) for the passage of the ends of the phases of the stator.

9. A traction assembly, characterized in that: It comprises a rotating electrical machine (10) according to any one of the preceding claims and a reducer element (22).

10. The traction assembly according to claim 9, characterized in that: The retarder element (22) is a motor vehicle gearbox.

11. The traction assembly according to claim 9, characterized in that: The speed reducer element (22) is a speed reducer which is mounted on a wheel train of a vehicle and is coupled to the rotating electric machine (10).

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