Electric motor equipped with a power supply device

Abstract

Electric motor equipped with a power supply device. Electric motor (1) for a motor vehicle comprising a stator (4) having at least one set of electric coils (71, 72), and a respective power supply device (91, 92) configured to supply electric current to the electric coils of each set of electric coils, each power supply device comprising a set of electric conductors (15, 16, 17, 18), each electric conductor comprising a first termination intended to be electrically connected to an electrical power source (2) and a second termination electrically connected to one end of at least one electric coil of the corresponding set of electric coils. Figure for the abbreviation: Figure 2

Description

Title of the invention: Electric motor equipped with an electric power supply device Technical field of the invention

[0001] The invention relates to an electric motor for a motor vehicle. The invention particularly relates to an electric power supply device and a cooling system of such an electric motor. The invention also relates to a motor vehicle equipped with such an electric motor. Prior art state

[0002] So-called "electric" or "hybrid" motor vehicles include an electric motor capable of driving the vehicle's drive wheels. Such an electric motor comprises a rotor coupled to the drive wheels and a stator. The electric motor, particularly the stator, is generally powered by a battery located on board the motor vehicle. High-intensity electric currents are used to obtain significant driving torque. In particular, electric motors are known to include a stator equipped with a set of electric coils designed to carry a high-intensity electric current. To supply the electric current to the coils, the electric motors are equipped with a power supply device comprising electrical conductors electrically connected to the electric coils.Electrical conductors, commonly called "bus bars," are generally made of copper strips with a cross-section large enough to carry a high-intensity electric current. It is also common to attach such a power supply device to the motor housing, the housing enclosing the stator and rotor. In addition to the relatively large cross-section of the electrical conductors, they must also be electrically insulated from each other, which necessitates minimum distances between them. Power supply devices for electric motors are therefore relatively bulky.

[0003] Furthermore, an electric motor needs to be cooled, particularly to dissipate the heat generated by the Joule effect when an electric current passes through the electrical conductors and coils. For this purpose, electric motors equipped with an oil cooling system are known. The oil in such a cooling system circulates in a closed circuit to cool the electric motor. Oil cooling systems known in the prior art are also bulky and do not cool the electric motor sufficiently effectively. In particular, these cooling systems do not do not cool the electrical conductors of the power supply device sufficiently effectively. Presentation of the invention

[0004] The object of the invention is to provide an electric motor for motor vehicles which remedies the above disadvantages and improves upon known electric motors of the prior art.

[0005] More specifically, a first object of the invention is a particularly compact electric motor that allows for the efficient cooling of electrical conductors of an electric motor power supply device. Summary of the invention

[0006] The invention relates to an electric motor for a motor vehicle comprising a stator provided with at least one set of electric coils, and a respective electric power supply device configured to supply electric current to the electric coils of each set of electric coils, each electric power supply device comprising a set of electric conductors, each electric conductor comprising a first termination intended to be electrically connected to an electrical power source and a second termination electrically connected to one end of at least one electric coil of the corresponding set of electric coils, each power supply device comprising a housing made of electrically insulating material within which the electric conductors are arranged, the housing comprising a first oil rail and a second oil rail,the first oil rail being configured to distribute oil against the stator to cool the electrical coils, the second oil rail being configured to collect oil from the stator, the electrical conductors extending at least partially into the first oil rail and / or the second oil rail.

[0007] The first oil rail and the second oil rail can each comprise a circular shape centered on an axis of rotation of a rotor of the electric motor, the circular shape of the first oil rail having a smaller diameter than the circular shape of the second oil rail.

[0008] Each electrical conductor may include a circular portion, the circular portion of each electrical conductor extending into the first oil ramp or into the second oil ramp.

[0009] The electric motor may include a rotor that rotates relative to the stator about an axis of rotation, and each housing of the power supply device may include a ring-shaped housing extending in a plane orthogonal to the axis of rotation, and the electric motor may include a casing enveloping the stator and rotor, the housing is arranged outside the casing against one face of the casing.

[0010] The first oil ramp may include a plurality of first holes distributed along the first oil ramp, said first holes being intended to distribute oil against the stator, and / or the second oil ramp may include a plurality of second holes distributed along the second oil ramp, said second holes being intended to collect oil from the stator.

[0011] Each electrical conductor may include an axial portion extending through a first hole or through a second hole.

[0012] The housing can be overmolded around the electrical conductors.

[0013] The power supply device may include an oil inlet communicating with the first oil rail and an oil outlet communicating with the second oil rail, the oil inlet being intended to be hydraulically connected to an oil pump, the oil outlet being intended to be hydraulically connected to a heat exchanger.

[0014] The electric motor may include a stator consisting of two parts framing a rotor, a first stator part being provided with a first set of electric coils and a second stator part being provided with a second set of electric coils, a first power supply device configured to supply the electric coils of said first set with electric current, a second power supply device configured to supply the electric coils of said second set with electric current, each power supply device comprising a set of electric conductors, each electric conductor comprising a first termination intended to be electrically connected to an electrical power source and a second termination electrically connected to one end of at least one electric coil of the first or second set of electric coils, respectively.each power supply unit comprising a housing made of electrically insulating material within which the electrical conductors are arranged, each housing comprising a first oil rail and a second oil rail, each first oil rail being configured to distribute oil inside the stator to cool the electrical coils, each second oil rail being configured to collect oil from the stator, the electrical conductors of the first power supply unit extending at least partially into the first oil rail and / or into the second oil rail of the housing of the first power supply unit, the electrical conductors of the second power supply unit extending at least partially into the first rail, of oil and / or in the second oil rail of the housing of the second power supply device, the electrical conductors of the first power supply device being electrically connected to the electrical conductors of the second power supply device by bonding conductors extending parallel to an axis of rotation of the electric motor rotor.

[0015] The invention also relates to a motor vehicle comprising an electric motor as defined above. Presentation of the figures

[0016] These objects, features and advantages of the present invention will be described in detail in the following description of a particular embodiment, given by way of non-limiting example, with reference to the accompanying figures, among which:

[0017] Fig. 1 is a schematic view of an electric motor for a motor vehicle according to an embodiment of the invention, the electric motor being hydraulically connected to an oil cooling system and electrically connected to an electrical power source.

[0018] Fig. 2 is a perspective view of the electric motor.

[0019] Figure 3 is a perspective view of a power supply device for the electric motor.

[0020] Fig. 4 is a perspective and exploded view of the power supply device. Detailed description

[0021] Figure 1 schematically illustrates an electric motor 1 for a motor vehicle according to an embodiment of the invention. The electric motor 1 is intended to drive the vehicle's drive wheels to propel the vehicle. To this end, the motor vehicle includes an electrical power source 2, in particular an electrochemical battery connected to the electric motor 1 via an electronic control unit 3. The electronic control unit includes power electronic components capable of supplying an electric current having intensity and / or voltage and / or frequency characteristics suitable for controlling the electric motor 1. The electric motor 1 includes, in particular, a stator 4 and a rotor 5 that rotates relative to the stator about an axis of rotation X. A rotating shaft 6 is fixed to the rotor 5 and is mechanically coupled to the vehicle's drive wheels by a mechanical transmission system.The rotor 5 may include a set of magnetic elements, including magnets, distributed on a ring centered on the axis of rotation X. The stator 4 includes at least one set of electrical coils 71, 72 distributed on the . less a crown also centered on the axis of rotation X. The electric coils 71, 72 are able to interact with the magnetic elements of the rotor 5 to convert an electric current into a rotational torque of the rotor.

[0022] According to the embodiment presented, the electric motor 1 is of the "axial flux" type, i.e., a magnetic field between the rotor 5 and the stator 4 is intended to be oriented parallel to the axis of rotation X. Alternatively, the electric motor could also be of the "radial flux" type, i.e., the magnetic field between the rotor 5 and the stator 4 would be intended to be oriented radially with respect to the axis of rotation X.

[0023] Furthermore, according to the embodiment presented, the stator 4 comprises two parts 41, 42 positioned on either side of the rotor 5 along the axis of rotation X. A first part 41 of the stator 4 comprises a first set of electrical coils 71, and a second part 42 of the stator 4 comprises a second set of electrical coils 72. Both sets of electrical coils 71, 72 cooperate with the same rotor 5. Each set of electrical coils 71, 72 can comprise, for example, between eight and thirty-two electrical coils. The individual electrical coils of each set are evenly distributed along a circle centered on the axis of rotation X.

[0024] The electric motor 1 also includes a housing 8 forming a sealed protective enclosure around the stator 4 and the rotor 5. The housing 8 may, in particular, be made of metallic walls, for example, aluminum or steel. The housing 8 generally has the shape of a cylinder of revolution whose axis of revolution coincides with the axis of rotation X.

[0025] Each electric coil 71, 72 comprises a winding of an electric wire having two ends. Each end of the electric wire is connected to the electrical power source 2 via the electronic control unit 3. For this purpose, the electric motor 1 comprises a first power supply device 91 configured to supply the first set of electric coils 71 and a second power supply device 92 configured to supply the second set of electric coils 72. The two power supply devices 91, 92 are arranged respectively on two opposite faces of the housing 8. The faces of the housing 8 on which the two power supply devices 91, 92 are arranged correspond to the two bases of the cylindrical shape of the housing.

[0026] As can be seen more clearly in [Fig. 2], the two power supply devices 91, 92 are electrically connected to each other by connecting conductors 11, 12, 13, 14 extending parallel to the axis of rotation X. According to the embodiment shown, the coils 71, 72 are supplied with electrical current by four types of connecting conductors. Three connecting conductors 11, 12, 13 are associated with a respective phase of an alternating electric current. The fourth connecting conductor is connected to ground. The electric motor 1 is thus supplied with three-phase power.

[0027] According to the embodiment presented, the electric motor 1 thus comprises a plane of symmetry substantially perpendicular to the axis of rotation X. In the following description, we will focus on describing more precisely the first electrical supply device 91 associated with the first part 41 of the stator 4, the design of the second electrical supply device 92 associated with the second part 42 of the stator 4 being symmetrically analogous to the design of the first electrical supply device 91 and can therefore be easily deduced by a person skilled in the art.

[0028] The power supply device 91 is illustrated in more detail in Figures 3 and 4. The power supply device comprises a ring-shaped element extending in a plane perpendicular to the axis of rotation X. It is arranged outside the housing 8 against one face of the housing, as explained previously. The diameter of the power supply device can be of the same order of magnitude as the diameter of the cylindrical shape of the housing 8, for example, equal to at least 70% and at most 100% of the diameter of the cylindrical shape of the housing 8. Furthermore, the power supply device 91 includes a central opening 15 through which the rotating shaft 6 passes.

[0029] The power supply device 91 comprises a set of electrical conductors 15, 16, 17, 18, in this case four electrical conductors. Each electrical conductor 15, 16, 17, 18 comprises a first termination electrically connected to the electrical power source 2, in particular respectively via the connecting conductors 11, 12, 13, 14 and via the electronic control unit 3. Each electrical conductor 15, 16, 17, 18 also comprises at least one second termination electrically connected to one end of an electrical coil of the set of electrical coils 71. Since there are more electrical coils than electrical conductors, each electrical conductor 15, 16, 17, 18 can be connected to several electrical coils 71.

[0030] The electrical conductors 15, 16, 17, 18, also called "bus bars," consist of a metal strip, preferably made of copper, and have a cross-section sufficient to carry a high-intensity electric current. Each electrical conductor 15, 16, 17, 18 can be obtained by cutting and bending a metal sheet. The individual electrical conductors are not in contact with each other. They can be separated from one another by an air gap, or more advantageously by an insulating plastic material.

[0031] Each electrical conductor 15, 16, 17, 18 comprises at least one axial portion 19 electrically connected to one end of a coil 71. Each axial portion 19 advantageously includes a forked end suitable for crimping around one end of an electrical wire of an electrical coil 71. The axial portions 19 of all the electrical conductors 15, 16, 17, 18 are evenly distributed along a circle centered on the axis of rotation X. Each electrical conductor 15, 16, 17, 18 also includes a radial portion 20 and a circular portion 21. The axial portion 19 and / or the radial portion 20 and / or the circular portion 21 of the same conductor may be welded to one another. Alternatively, each electrical conductor 15, 16, 17, 18 may be a monolithic element, that is, made of a single piece. Each radial portion 20 extends between a circular portion 21 and a connecting conductor from among the set of connecting conductors 11, 12, 13, 14. Each radial portion 20 can take the form of a plate extending globally in a plane perpendicular to the axis of rotation X.Each circular portion 21 extends along a circle centered on the axis of rotation X, between a radial portion 20 and at least one axial portion 19. The circular portions 21 allow the distribution of electric current to different coils distributed around the axis of rotation X. Each circular portion 21 can take the form of a plate extending parallel to the axis of rotation X.

[0032] The power supply device 91 also includes a housing 22 made of insulating material, preferably plastic, inside which the electrical conductors are arranged. In one embodiment, the housing 22 can be overmolded around the electrical conductors 15, 16, 17, 18. This allows the electrical conductors 15, 16, 17, 18 to be separated by a plastic material and thus improves the electrical insulation of the individual conductors. Alternatively, and as shown in Figures 3 and 4, the housing 22 can be formed by assembling a base 23 and a cover 24. The base 23 and the cover 24 can each be made of plastic, in particular obtained by molding. The base 23 and the cover 24 can be assembled to each other along a joining plane perpendicular to the axis of rotation X. The power supply device 91 can be attached to the housing 8 via its casing 22.The housing can advantageously be provided with a radial protrusion in which the radial portions of the electrical conductors extend.

[0033] Furthermore, with reference to [Fig. 1], the electric motor 1 also includes an oil cooling system 25. The oil cooling system 25 comprises a closed oil circuit 26, an oil pump 27 for circulating the oil in the oil circuit 26, and a heat exchanger 28 for dissipating the heat stored by the oil. The oil circuit 26 extends, in particular, inside the housing 8. The oil can thus come into direct contact with the stator's electrical coils and cool them. The oil cooling system 25 makes it possible to maintain the temperature of the electric motor 1 sufficiently low to preserve the electric motor and allow its optimal operation.

[0034] In addition to its function of protecting the electrical conductors 15, 16, 17, 18, the housing 22 also forms part of the oil cooling system 25, and in particular part of the oil circuit 26. In particular, and as can be more clearly seen in [Fig. 4], the housing 22 comprises a first oil rail 29 and a second oil rail 30. Each oil rail 29, 30 is a channel for conveying oil. In particular, each oil rail 29, 30 can be formed by a groove on the housing 22, especially on the base 23.

[0035] The first oil rail 29 is configured to distribute oil inside the housing 8, in particular to distribute oil against the stator to cool the electric coils 71. The second oil rail 30 is configured to collect oil from the stator. In particular, according to one embodiment, the housing 22 also includes an oil inlet and an oil outlet. The oil inlet can be hydraulically connected upstream to the oil pump 27 by an oil line, and downstream to the first oil rail 29. The oil outlet can be hydraulically connected downstream to the heat exchanger 28 by an oil line, and upstream to the second oil rail 30. According to another embodiment, the oil pump 27 and / or the heat exchanger 28 could be positioned at different locations in the oil circuit 26.The first oil rail 29 could then be hydraulically connected to the second oil rail 30 via hydraulic connecting lines uninterrupted by the oil pump 27 or the heat exchanger 28. These hydraulic connecting lines could even extend inside the housing 22 between the first oil rail 29 and the second oil rail 30, for example along a radial path. In all cases, the housing 22, which contains the electrical conductors 15, 16, 17, 18, is advantageously used to distribute cooled oil around the stator and to collect heated oil from the stator.

[0036] Furthermore, the electrical conductors 15, 16, 17, 18 extend at least partially into the first oil rail 29 and / or the second oil rail 30. Thus, the first oil rail and / or the second oil rail also serve to cool the electrical conductors 15, 16, 17, 18, which are components that can heat up considerably when carrying such an electric current. In this case, according to the embodiment presented, the electrical conductors 15, 16, 17, 18 extend partially into the first oil rail 29. Alternatively, they could extend into the second oil rail 30.

[0037] Advantageously, the first oil ramp 29 and the second oil ramp 30 each comprise a circular shape centered on the axis of rotation X. The two The oil ramps 29 and 30 are concentric, and even substantially coplanar. The oil ramps extend 360° around the axis of rotation X, which allows for uniform distribution of the oil around the stator 4 and efficient collection of the oil from the stator 4. According to the embodiment shown, the circular shape of the first oil ramp 29 has a smaller diameter than the circular shape of the second oil ramp 30. This configuration is advantageous because the oil tends to follow a centrifugal motion inside the housing 8 due to the rotation of the rotor 5. The oil therefore more easily follows a path in which it enters the housing 8 at points close to the axis of rotation X and exits the housing 8 at points further from the axis of rotation X.According to one embodiment, the oil drive in the oil circuit 26 could even be achieved by the rotation of the rotor 5 alone, thus saving the oil pump 27. According to another embodiment, an inverse configuration could nevertheless be envisaged: the circular shape of the first oil rail 29 could have a larger diameter than the circular shape of the second oil rail 30.

[0038] Since the oil rails 29, 30 have a circular shape, it is advantageously the circular portions 21 of each electrical conductor 15, 16, 17, 18 that extend into the first oil rail 29 or into the second oil rail 30. The oil rail accommodating the electrical conductors 15, 16, 17, 18 therefore has dimensions adapted to accommodate the electrical conductors 15, 16, 17, 18.

[0039] The first oil rail 29 comprises a plurality of first holes 31 distributed along the first oil rail. The first holes 31 are intended to distribute the oil inside the housing 8, against the stator 4. Advantageously, the first holes 31 also serve as passageways for the electrical conductors 15, 16, 17, 18, in particular for the axial portions 19 of these electrical conductors. The oil can thus be more easily guided to the electrical coils 71. Similarly, the second oil rail 30 comprises a plurality of second holes 32 distributed along the second oil rail. The second holes 31 are intended to collect the oil from the stator 4. As can be seen in [Fig. 4], a ring 33 may optionally be provided in the second oil rail 30 to guide the oil along the second oil rail to the oil outlet.

[0040] Finally, a particularly compact and easy-to-manufacture electric motor 1 is obtained. When the electric motor 1 is operating, electric currents flow in the electrical conductors 15, 16, 17, 18 and in the electrical coils 71, which contributes to their heating. In parallel, oil is circulated in the oil circuit, notably by means of the oil pump 27. When the oil arrives In the first oil rail 29, the oil follows a circular motion and supplies the stator with 360° of rotation around its axis. In doing so, the oil cools the electrical conductors 15, 16, 17, 18 and the electrical coils 71. The oil, heated by contact with the electrical conductors 15, 16, 17, 18 and the electrical coils 71, exits the housing 8 and is collected by the second oil rail 30. The oil also follows a circular motion in the second oil rail before exiting the housing 22 through the oil outlet. The oil is then cooled by the heat exchanger. A new oil circulation cycle can then begin.

Claims

Demands

1. Electric motor (1) for a motor vehicle comprising a stator (4) having at least one set of electric coils (71, 72), and a respective power supply device (91, 92) configured to supply electric current to the electric coils of each set of electric coils, each power supply device comprising a set of electric conductors (15, 16, 17, 18), each electric conductor comprising a first termination intended to be electrically connected to an electrical power source (2) and a second termination electrically connected to one end of at least one electric coil of the corresponding set of electric coils, each power supply device comprising a housing (22) of electrically insulating material within which the electric conductors (15, 16, 17, 18) are arranged,the housing comprising a first oil rail (29) and a second oil rail (30), the first oil rail being configured to distribute oil against the stator to cool the electrical coils, the second oil rail being configured to collect oil from the stator, the electrical conductors (15, 16, 17, 18) extending at least partially into the first oil rail and / or into the second oil rail.

2. Electric motor according to the preceding claim, characterized in that the first oil rail (29) and the second oil rail (30) each comprise a circular shape centered on an axis of rotation (X) of a rotor (5) of the electric motor, the circular shape of the first oil rail (29) having a smaller diameter than the circular shape of the second oil rail (30).

3. Electric motor according to the preceding claim, characterized in that each electric conductor (15, 16, 17, 18) comprises a circular portion (21), the circular portion of each electric conductor extending into the first oil rail (29) or into the second oil rail (30).

4. An electric motor according to any one of the preceding claims, characterized in that it comprises a rotor movable in rotation relative to the stator (4) about an axis of rotation (X), and in that each housing (22) of the power supply device electric (91, 92) includes a crown shape extending in a plane orthogonal to the axis of rotation (X), and in that the electric motor includes a housing (8) enclosing the stator (4) and the rotor (5), the casing (22) being arranged outside the housing against one face of the housing.

5. Electric motor according to any one of the preceding claims, characterized in that the first oil rail (29) comprises a plurality of first holes (31) distributed along the first oil rail, said first holes being intended to distribute oil against the stator, and / or in that the second oil rail (30) comprises a plurality of second holes (32) distributed along the second oil rail, said second holes being intended to collect oil from the stator.

6. Electric motor according to the preceding claim, characterized in that each electrical conductor (15, 16, 17, 18) comprises an axial portion (19) extending through a first hole (31) or through a second hole (32).

7. Electric motor according to any one of the preceding claims, characterized in that the housing (22) is overmolded around the electrical conductors (15, 16, 17, 18).

8. Electric motor according to any one of the preceding claims, characterized in that the power supply device (91, 92) comprises an oil inlet communicating with the first oil rail (29) and an oil outlet communicating with the second oil rail (30), the oil inlet being intended to be hydraulically connected to an oil pump (27), the oil outlet being intended to be hydraulically connected to a heat exchanger (28).

9. An electric motor according to any one of the preceding claims, characterized in that it comprises a stator (4) consisting of two parts (41, 42) framing a rotor (5), a first stator part being provided with a first set of electric coils (71) and a second stator part being provided with a second set of electric coils (72), a first power supply device (91) configured to supply the electric coils of said first set with electric current, a second power supply device (92) configured to supply the electric coils of said second set with electric current, each

10. power supply device comprising a set of electrical conductors (15, 16, 17, 18), each electrical conductor comprising a first termination intended to be electrically connected to an electrical power source (2) and a second termination electrically connected to one end of at least one electrical coil of the first or second set of electrical coils, each power supply device comprising a housing (22) of electrically insulating material within which the electrical conductors are arranged, each housing comprising a first oil rail (29) and a second oil rail (30), each first oil rail being configured to distribute oil inside the stator to cool the electrical coils (71, 72), each second oil rail being configured to collect oil from the stator,the electrical conductors of the first power supply device extending at least partially into the first oil rail and / or the second oil rail of the housing of the first power supply device, the electrical conductors of the second power supply device extending at least partially into the first oil rail and / or the second oil rail of the housing of the second power supply device, the electrical conductors of the first power supply device being electrically connected to the electrical conductors of the second power supply device by connecting conductors (11, 12, 13, 14) extending parallel to an axis of rotation (X) of the rotor (5) of the electric motor. Motor vehicle comprising an electric motor (1) according to one of the preceding claims.

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