FR3063201A1 - ROTATING ELECTRIC MACHINE INVERTER WITH IMPROVED COOLING - Google Patents

Abstract

The invention relates mainly to an inverter (26) for a rotating electrical machine (10) for a motor vehicle comprising: - an electrical power module (35) mounted inside a protective casing (36), - a dissipator heat sink (40) for discharging heat from the electric power module (35), - said heat sink (40) having fins (41), characterized in that the fins (41) are configured to exchange heat with an oil (28), and in that the inverter (26) has a sealing means (45) configured to isolate the protective housing (36) from the oil (28).

Description

Holder (s): VALEO ELECTRIC EQUIPEMENTS MOTOR Simplified joint-stock company.

Extension request (s)

Agent (s): VALEO EQUIPEMENTS ELECTRIQUES MOTOR Simplified joint-stock company.

INVERTER OF ROTATING ELECTRIC MACHINE WITH IMPROVED COOLING.

FR 3 063 201 - A1 ft ”) The invention relates mainly to an inverter (26) of a rotating electrical machine (10) for a motor vehicle comprising:

- an electrical power module (35) mounted inside a protective housing (36),

- a heat sink (40) for removing heat from the electrical power module (35),

- Said heat sink (40) comprising fins (41), characterized in that the fins (41) are configured to exchange heat with an oil (28), and in that the inverter (26) comprises means seal (45) configured to isolate the protective housing (36) from the oil (28).

INVERTER OF ROTATING ELECTRIC MACHINE WITH IMPROVED COOLING

The present invention relates to a rotary electric machine inverter with improved cooling. The invention finds a particularly advantageous, but not exclusive, application with reversible high-power electric machines capable of operating in alternator mode and in motor mode coupled with a host element such as a gearbox.

In a manner known per se, rotary electrical machines comprise a stator and a rotor secured to a shaft. The rotor may be integral with a driving and / or driven shaft and may belong to a rotating electrical machine in the form of an alternator, an electric motor, or a reversible machine capable of operating in both modes.

The stator is mounted in a casing configured to rotate the shaft on bearings by means of bearings. The rotor comprises a body formed by a stack of sheets of metal sheets held in the form of a package by means of a suitable fixing system. The rotor has poles formed for example by permanent magnets housed in cavities formed in the magnetic mass of the rotor. Alternatively, in a so-called salient pole architecture, the poles are formed by coils wound around the rotor arms.

Furthermore, the stator comprises a body constituted by a stack of thin sheets forming a crown, the inner face of which is provided with notches open towards the inside to receive phase windings. These windings pass through the notches in the stator body and form buns protruding from either side of the stator body. The phase windings are obtained for example from a continuous wire covered with enamel or from conductive elements in the form of pins connected together by welding. These windings are polyphase windings connected in star or triangle whose outputs are connected to an inverter also operating as a rectifier bridge.

In certain types of traction chains of a motor vehicle ensuring the transmission of mechanical power from the heat engine to the wheels of the vehicle, a high power reversible rotating electric machine is coupled to the vehicle gearbox. The electric machine is then able to operate in an alternator mode in particular to supply energy to the battery and to the on-board network of the vehicle, and in an engine mode, not only to ensure the starting of the heat engine, but also to participate traction of the vehicle alone or in combination with the engine.

The present invention aims to improve the cooling of the inverter of the electric machine by taking advantage of the presence of oil in the crankcase of the gearbox.

To this end, the invention proposes an inverter of a rotating electric machine for a motor vehicle comprising:

- an electric power module mounted inside a protective box,

- a heat sink to remove heat from the electrical power module,

- Said heat sink comprising fins, characterized in that the fins are configured to exchange heat with an oil, and in that the inverter comprises a sealing means configured to isolate the protective housing from the oil.

The invention thus makes it possible, thanks to the presence of the fins, to efficiently extract the calories produced by the electronic power module, which improves the electrical and mechanical performance of the rotary electrical machine.

According to one embodiment, the sealing means is an O-ring type.

According to one embodiment, the heat sink has a groove for receiving the seal.

According to one embodiment, the fins have a rounded edge.

According to one embodiment, the fins have a frustoconical shape.

According to one embodiment, the fins have a cylindrical shape.

According to one embodiment, said inverter includes ears for the passage of fixing members ensuring in particular a fixing between the protective housing and the heat sink.

According to another aspect, the subject of the invention is an assembly comprising:

- a gearbox fitted with a casing and gear wheels, said casing containing oil,

- a rotating electric machine, and

- an inverter electrically connected to the rotary electric machine, characterized in that the inverter is fixed to the gearbox casing and in that the inverter comprises a heat sink comprising fins, the fins extending to the inside the housing so as to receive oil sprayed by the gear wheels of the gearbox.

According to one embodiment, said rotary electrical machine is located inside the casing of the gearbox.

According to one embodiment, the rotary electric machine is located outside of the gearbox casing.

According to one embodiment, the inverter is electrically connected to the rotary electrical machine via a sealed connection cable extending inside the casing of the gearbox.

According to one embodiment, the protective housing of the inverter is located outside the gearbox casing.

According to one embodiment, a seal is positioned between the gearbox casing and the heat sink.

According to one embodiment, at least part of the fins is positioned opposite an intersection between two gear wheels.

According to one embodiment, the fins extend substantially perpendicular to a plane comprising the axes of the wheels of the gear. This optimizes the spraying of oil to the cooling fins of the heat sink.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given only by way of illustration but in no way limit the invention.

Figure 1 is a longitudinal sectional view of a rotary electrical machine used with an inverter according to the present invention;

Figure 2 is a schematic representation of an assembly of the rotary electrical machine of Figure 1 with a gearbox;

FIG. 3 is a perspective view of the inverter according to the present invention;

Figure 4 is a schematic side view of the gearbox illustrating the projection of oil to the fins of the inverter according to the present invention installed on a gearbox housing.

Identical, similar, or analogous elements retain the same reference from one figure to another.

In the following description, the term “front element” means an element situated on the side of the pinion carried by the machine shaft and “rear element” means an element situated on the opposite side.

FIG. 1 shows a rotary electrical machine 10 comprising a polyphase stator 11 surrounding a rotor 12 mounted on a shaft 13 of axis X. The stator 11 surrounds the rotor 12 with the presence of an air gap between the internal periphery of the stator 11 and the outer periphery of the rotor 12. The stator 11 is mounted in a casing 14 provided with a front bearing 17 and a rear bearing 18.

This electric machine 10 is intended to be coupled to a gearbox 16 visible in FIG. 2 belonging to a traction chain of a motor vehicle. The machine 10 is capable of operating in an alternator mode in particular to supply energy to the battery and to the on-board network of the vehicle, and in an engine mode, not only to ensure the starting of the heat engine of the vehicle, but also for participate in vehicle traction alone or in combination with the heat engine. The power of the machine 10 can be between 15kW and 50kW.

More specifically, the rotor 12 comprises a body 19 in the form of a pack of sheets. Permanent magnets 20 are implanted in cavities 21 of the body 19. The magnets 20 can be made of rare earth or ferrite depending on the applications and the desired power of the machine 10. Alternatively, the poles of the rotor 12 can be formed by coils .

Furthermore, the stator 11 comprises a body 23 constituted by a package of sheets as well as a coil 24. The body 23 is formed by a stack of sheets of sheets independent of each other and held in the form of a package by means of '' a suitable fixing system. This body 23 is provided with teeth defining two by two of the notches for mounting the winding 24 of the stator 11.

The winding 24 comprises a set of phase windings passing through the notches and forming buns projecting on either side of the stator body 23. The phase windings are obtained here from shaped conductive elements pins connected to each other, for example by welding. These windings are for example three-phase windings connected in a star or a triangle. The outputs of the phase windings are connected to an inverter 26 which can also operate if necessary as a rectifier bridge.

As can be seen in FIG. 2, the machine 10 is positioned inside the casing 27 of the gearbox 16 filled with oil 28 for the lubrication of the mechanical components of the gearbox 16.

The electric machine 10 is arranged in the internal volume of the casing 27, so that the pinion 30 carried by the shaft 13 cooperates with a corresponding gear wheel 31 of the gearbox 16.

To this end, the rear bearing 18 carries a bearing 34 for the rotational mounting of the shaft 13. In addition, the free end of the shaft 13 projecting from the casing 14 of the electric machine 10 is rotatably mounted via another bearing 34 carried by the casing 27 of the gearbox 16. Thus, the machine 10 comprises a single bearing 34, which facilitates the mounting of the machine 10 inside the gearbox 16 and limits the risks of hyperstatism of the whole.

More specifically, as can be seen in FIG. 3, the inverter 26 comprises an electrical power module 35 mounted inside a protective housing 36 made of an insulating material, such as plastic. This electric power module 35 comprises arms each provided with two power switching elements, such as MOS type transistors, and each connected to a corresponding phase winding of the stator 11 via the input terminals 29 The inverter 26 is electrically connected to the electric machine 10 via a sealed connection cable 38 extending inside the casing 27 of the gearbox 16, as shown in FIG. the connection cable 38 extends outside the casing 27 of the gearbox 16 in the direction of the electric machine.

In addition, a heat sink 40 made of a thermally conductive material allows the calories generated by the electric power module 35 to be removed. Preferably, the heat sink

40 is made of a metallic material, such as aluminum. The heat sink 40 is provided with cooling fins 41 configured to exchange heat with the oil 28 of the gearbox 16. The fins 41, preferably with rounded edges, may in particular have a frustoconical shape, such as that is shown in the figures

3 and 4 or a cylindrical shape. This prevents oil retention by the fins 41 as much as possible. As a variant, the fins 41 may however have a rectangle, square or semi-circular section. It depends on the application.

For this purpose, the casing 27 of the gearbox 16 has a hole 42 in its upper part allowing the passage of the fins 41 of the heat sink 40 inside the casing 27, as illustrated in FIG. 4. L inverter 26 plugs said through hole 42 when it is fixed to the wall of the casing 27. In order to isolate the housing 36 of the inverter 26 located outside the casing 27 with respect to the oil 28 of the gearbox 16, the passage hole 42 is sealed by a sealing means, such as an O-ring 45, positioned between the heat sink 40 and an edge of the casing 27 delimiting the passage hole 42. This seal 45 is mounted inside a groove 46 formed in the heat sink 40.

The inverter 26 has ears 48 for the passage of fixing members 49, such as screws, ensuring a fixing between the housing 36 and the heat sink 40. These fixing members 49 may also ensure the fixing of the inverter 26 on the casing 27 of the gearbox 16.

In operation, the oil 28 is sprayed by the gear wheels 31 of the gearbox 16 partially immersed in the oil 28 towards the fins 41 of the dissipator 40 extending inside the casing 27.

Indeed, due to the centrifugal forces linked to the rotation of the gear wheels 31, the oil 28 is projected radially and in the direction of rotation of the wheels 31 in the direction of the fins 41 according to the arrows F.

In order to optimize the spraying of oil 28 onto the fins 41, at least a portion of the fins 41 is positioned facing the intersection of the gear wheels 31 rotating in two opposite directions of rotation R1 and R2 relative to each other. In addition, the fins 41 may extend substantially perpendicular to the plane P comprising the axes of the gear wheels.

31.

Alternatively, the rotary electric machine 10 may be located outside the casing 27 of the gearbox 16, as shown in FIG. 4 by the dotted lines.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention from which one would not depart by replacing the various elements with any other equivalent.

Furthermore, the various features, variants, and / or embodiments of the present invention can be combined with one another in various combinations, insofar as they are not incompatible or mutually exclusive of one another.

Claims (13)

1. Inverter (26) of a rotary electrical machine (10) for a motor vehicle comprising: - an electric power module (35) mounted inside a 5 protective case (36), - a heat sink (40) for removing heat from the electrical power module (35), - Said heat sink (40) comprising fins (41), characterized in that the fins (41) are configured to exchange heat with oil (28), and in that the inverter (26) comprises a sealing means (45) configured to isolate the protective housing (36) from the oil (28). 2. Inverter according to claim 1, characterized in that the sealing means is a seal (45) of the O-ring type. 15 3. Inverter according to claim 2, characterized in that the heat sink (40) has a groove (46) for receiving the seal (45). 4. Inverter according to any one of claims 1 to 3, characterized in that the fins (41) are with rounded edges. 20 5. Inverter according to claim 4, characterized in that the fins (41) have a frustoconical shape. 6. Inverter according to claim 4, characterized in that the fins (41) have a cylindrical shape. 7. Inverter according to any one of claims 1 to 6, 25 characterized in that it comprises ears (48) for the passage of fixing members (49) ensuring in particular a fixing between the protective housing (36) and the heat sink (40). 8. Set comprising: - a gearbox (16) provided with a casing (27) and gear wheels (31), said casing (27) containing oil (28), - a rotating electric machine (10), and - an inverter (26) electrically connected to the rotary electrical machine (10), characterized in that the inverter (26) is fixed to the casing (27) of the gearbox (16) and in that the inverter ( 26) comprises a heat sink (40) comprising fins (41), the fins (41) extending inside the casing (27) so as to receive oil (28) projected by the wheels of gearbox (31) of the gearbox (16), the inverter (26) comprising a protective box (36) located outside the casing (27) of the gearbox (16), a seal (45 ) being positioned between the casing (27) of the gearbox (16) and the heat sink (40). 9. An assembly according to claim 8, characterized in that said rotary electrical machine (10) is located inside the casing (27) of the gearbox (16). 10. The assembly of claim 8, characterized in that the rotary electric machine (10) is located outside the housing (27) of the gearbox (16). 11. An assembly according to any one of claims 8 to 10, characterized in that the inverter (26) is electrically connected to the rotary electrical machine (10) via a waterproof connection cable (38) extending to the inside of the gearbox casing (27). 12. Assembly according to any one of claims 8 to 11, characterized in that at least a part of the fins (41) is positioned opposite an intersection between two gear wheels (31). 13. The assembly of claim 12, characterized in that the fins (41) extend substantially perpendicular to a plane (P) comprising the axes of the wheels of the gear (31). 1/2 2/2