Cooling circuit for electric machine

Abstract

The invention relates to a rotating electrical machine (1) comprising: - an electric motor (2), formed by a rotor (21) rotatable about a shaft (22) and a fixed stator (23) surrounding the rotor, extending along an axis (X), - a casing (11) surrounding the motor (2), - a cooling system (4) allowing the passage of a cooling liquid, and - an electronic assembly (3) mounted on the casing and comprising at least one power module (22) arranged on a heat sink (40) of the cooling system (4), the cooling system comprising a first conduit (41) supplying the sink (40), the first conduit (41) being arranged at the casing (24) of the motor (2). Figure to be published with the abstract: 3

Description

Title of the invention: Cooling circuit for an electric machine

[0001] The present invention relates to the field of electrical machines, and more particularly to a cooling circuit for a rotating electrical machine for a mobility device and for example a motor vehicle.

[0002] The rotating electrical machines concerned by the present invention are, for example, alternators, alternator-starters, reversible machines or electric motors.

[0003] A rotating electrical machine comprises a motor formed by a rotor that is mobile and rotates around an axis and a fixed stator surrounding the rotor. In alternator mode, when the rotor is rotating, it induces a magnetic field in the stator which transforms it into electric current in order to power the electrical consumers of the vehicle and to recharge the battery. In motor mode, the stator is electrically powered and induces a magnetic field driving the rotor in rotation. The rotating electrical machine also comprises an electronic assembly comprising several power modules for rectifying the current supplied by the stator. This electronic assembly is mounted on the casing of the machine and in particular on one of the flanges forming the casing.

[0004] During operation of the rotating electrical machine, whatever its operating mode, it is important that it is cooled. In particular the electronic assembly and the stator.

[0005] This type of machine is usually cooled by a cooling system comprising a cooling fluid. The system traverses the entire electronic assembly and circulates around the engine. A drawback of these cooling systems is that they are fed by a cooling fluid supply coming directly from the rest of the vehicle, which is cumbersome. It is thus difficult to integrate the electric machine into the vehicle.

[0006] The present invention therefore aims to overcome one or more of the drawbacks of the devices of the prior art by providing an improved cooling system for an electric machine.

[0007] To this end, the present invention provides a rotating electric machine comprising: - an electric motor, formed by a rotating movable rotor around a shaft and a fixed stator surrounding the rotor, extending along an axis, - a casing surrounding the engine, - a cooling system allowing the passage of a coolant, and - an electronic assembly mounted on the casing and comprising at least one power module placed on a heat sink of the cooling system,

[0008] the cooling system comprising a first conduit supplying the heat sink, the first conduit being arranged at the level of the motor casing.

[0009] It is important that the power electronic device is cooled, by the heat sink, before the motor to ensure better operating performance of the electronic assembly which requires more cooling than the motor.

[0010] According to one embodiment of the invention, the first conduit is arranged perpendicular to the axis of the shaft and perpendicular to the heat sink.

[0011] According to one embodiment of the invention, the inlet of the first conduit is pressed against the casing, the first conduit forming a zigzag in the direction of the heat sink.

[0012] According to one embodiment of the invention, the first conduit forms a first elbow directing the conduit towards the machine, then a second elbow directing the conduit towards the heat sink.

[0013] According to one embodiment of the invention, the first conduit opens into the heat sink.

[0014] According to one embodiment of the invention, the first conduit is fixed to the casing, for example the first conduit is pressed and glued to the casing.

[0015] The inlet duct is thus pressed against the casing, as close as possible to the machine, which reduces the size of the machine and facilitates its integration into the vehicle or mobility device.

[0016] According to one embodiment of the invention, the cooling system comprises an additional conduit acting as an outlet conduit, and a circular cooling circuit of the engine opening into this additional conduit.

[0017] Indeed, it is important that the cooling circuit is arranged completely around the engine housing to ensure a good cooling effect.

[0018] According to one embodiment of the invention, the additional conduit is arranged at the level of the engine casing.

[0019] According to one embodiment of the invention, the additional conduit is arranged parallel to the first conduit, pressed against the casing, and for example fixed, pressed and glued to the casing.

[0020] Such a cooling system reduces the size of the machine and facilitates its integration into the vehicle or mobility device.

[0021] The invention also relates to a motor vehicle comprising a machine rotating electric according to the invention.

[0022] Other aims, characteristics and advantages of the invention will be better understood and will appear more clearly on reading the description given below, with reference to the appended figures, given by way of example and in which: - [Fig.l] is a transparent elevation view of an electrical machine with a cooling system according to the invention, - [Fig.2] is an elevation view of an electrical machine with a cooling system according to the invention, - [Fig.3] is a cross-sectional view of an electrical machine with a cooling system according to the invention.

[0023] The present invention [Fig.l] relates to a rotating electrical machine 1 comprising a cooling circuit with coolant. The electrical machine 1 is a machine for a mobility device with at least 2 wheels, and for example with 4 wheels such as a motor vehicle.

[0024] The invention applies for example to the field of rotating electrical machines such as alternators, reversible machines such as alternator-starters or electric motors.

[0025] According to an embodiment of the invention, visible [Fig.l] to [Fig.3], the rotating electrical machine 1 comprises a motor 2, an electronic assembly 3 and a cooling system 4.

[0026] According to an embodiment of the invention, visible [Fig.3], the motor 2 comprises a rotor 21 movable in rotation around a shaft 22 and a fixed stator 23 surrounding the rotor. The rotational movement of the rotor 21 is around an axis X.

[0027] In alternator mode, when the rotor is rotating, it induces a magnetic field in the stator which transforms it into electric current in order to supply the electrical consumers of the vehicle and recharge the battery. In motor mode, the stator is electrically powered and induces a magnetic field driving the rotor into rotation.

[0028] According to one embodiment of the invention, the motor is arranged in a casing 24. According to one embodiment of the invention, the casing 24 has a shape adapted to receive the motor 2 and for example has a cylinder shape with a longitudinal axis parallel to the axis 22 of the motor.

[0029] According to one embodiment of the invention, the casing has a flattened face 25. That is to say that a section of the cylinder is flat. This face 25 is considered to be the rear face 25 of the casing 24. The cylinder is closed by two plates arranged at the ends. The casing 24 makes it possible to maintain and protect the motor 2 formed by the stator 23 and the rotor 22.

[0030] According to one embodiment of the invention, the casing 24 comprises fixing means, not shown, allowing the mounting of the rotating electrical machine 1 in or on a mobility device.

[0031] In the context of the invention, the electronic assembly is mounted on the casing 24 of the engine 2, more precisely on the rear longitudinal face 25 forming a part of the cylinder of the casing 24.

[0032] According to one embodiment of the invention, the electronic assembly 3 comprises at least one electronic power module 31. The electronic power module 31 is mounted on a heat sink 40 allowing it to be cooled. The sink is part of the cooling system of the machine 1. According to one embodiment of the invention, the sink is arranged parallel to the axis X of the shaft 22, on the rear longitudinal face 25 of the casing 24 of the motor 2.

[0033] According to one embodiment of the invention, the heat sink 40 is formed by a chamber or a channel which is supplied with cooling fluid by a first conduit 41, of the cooling system 4, which acts as an inlet conduit. This first conduit 41 is itself supplied by the cooling assembly of the machine or vehicle.

[0034] In the context of the invention, this first conduit 41 is arranged at the level of the casing 24 of the motor 2. More precisely, the first conduit 41 is arranged perpendicular to the axis X of the shaft 22 and perpendicular to the heat sink 40. According to one embodiment of the invention, the inlet 410 of the first conduit 41 is pressed against the casing 24, the first conduit 41 then forming a zigzag in the direction of the heat sink 40. More precisely, the first conduit 41 forms a first bend 411 directing the conduit towards the machine, then a second bend 412 directing the conduit towards the heat sink 40. The two bends 441, 412 are in the same axial plane of the axis 22 of the motor 2. According to one embodiment of the invention, the first conduit 31 opens under the electronic assembly 3, and more precisely in the heat sink 40 at the level from its face facing machine 2.

[0035] According to one embodiment of the invention, the seal between the first conduit 41 and the dissipator 40 is achieved with a flat seal.

[0036] According to one embodiment of the invention, the first conduit 41 is fixed to the casing 24.

[0037] According to one embodiment of the invention, the first conduit 41 is pressed and glued to the casing 24.

[0038] The inlet duct 41 is thus pressed against the casing 24, as close as possible to the machine 1, which reduces the size of the machine and facilitates its integration into the vehicle or mobility device.

[0039] According to one embodiment of the invention, the cooling system 4 comprises a second conduit 42 opening from the heat sink 40 to connect it to the cooling circuit 44 of the engine.

[0040] According to one embodiment of the invention, the seal between the dissipator 40 and the second conduit 42 is achieved with a flat seal.

[0041] According to one embodiment of the invention, the seal between the second conduit 42 and the cooling circuit 44 of the engine 2 is achieved with a flat seal.

[0042] According to one embodiment of the invention, the cooling circuit 44 of the engine, of the cooling system, is formed by a circular chamber 44, that is to say arranged circularly around the engine 2, between the engine 2 and the casing 24. Indeed, it is important that the cooling circuit 44 is arranged completely around the casing of the rotating engine 2 to ensure a good cooling effect.

[0043] According to one embodiment of the invention, the height h of chamber 44, that is to say its dimension parallel to the axis X of the shaft 22 is identical to the height of the motor 2, so as to optimize cooling.

[0044] According to one embodiment of the invention, the thickness e of the chamber 44 of the engine 2 is less than the height h.

[0045] In the context of the invention, the cooling system comprises an additional conduit 43 acting as an outlet conduit, the circular chamber 44 opening into this additional conduit 43.

[0046] According to one embodiment of the invention, the seal between the cooling circuit 44 of the engine and the additional conduit 43 is achieved with a flat seal.

[0047] According to one embodiment of the invention, this additional conduit 43 then opens into the cooling assembly of the machine or vehicle.

[0048] In the context of the invention, this additional conduit 43 is arranged at the level of the casing 24 of the motor 2. More precisely, the additional conduit 43 is arranged perpendicular to the axis X of the shaft 22 and parallel to the first conduit 31.

[0049] According to one embodiment of the invention, the outlet 413 of the additional conduit 43 is pressed against the casing 24.

[0050] According to one embodiment of the invention, the additional conduit 43 is fixed to the casing 24.

[0051] According to one embodiment of the invention, the additional conduit 43 is pressed and glued to the casing 24.

[0052] The outlet duct 43 is thus pressed against the casing, as close as possible to the machine, which reduces the size of the machine and facilitates its integration into the vehicle or mobility device.

[0053] The inlet 410 and the outlet 413 of the cooling fluid in the cooling system 4 are thus arranged at the same level, the openings of the first conduit and of the additional conduit being oriented in the same direction.

[0054] Such a cooling system reduces the size of the machine and facilitates its integration into the vehicle or mobility device.

[0055] According to one embodiment, the spacing between the inlet and the outlet of the cooling chamber 44 of the engine 2 is defined to optimize the circulation of the coolant.

[0056] According to one embodiment of the invention, the cooling fluid is a cooling liquid, and for example water or any other liquid having the properties necessary for cooling the machine 1.

[0057] Thus, during operation of the electrical machine 1, the cooling fluid arrives from the machine or vehicle via the inlet 410 of the first conduit 41. The fluid then passes into the heat sink 40 to cool the electronic assembly before the motor 2. Indeed, it is important that the power electronic device is cooled before the motor 2 to guarantee better operating performance of the electronic assembly which requires more cooling than the motor 2.

[0058] The cooling fluid then passes into the second conduit 42 and then opens into the cooling chamber 44. It is then evacuated through the additional conduit 43, and exits through the outlet 413 of this conduit 43.

[0059] The cooling of the electronic assembly 3 and the motor 2 allows better operating performance of the electric machine 1.

[0060] The scope of the present invention is not limited to the details given above and allows embodiments in many other specific forms without departing from the scope of the invention. Therefore, the present embodiments should be considered by way of illustration, and may be modified without departing from the scope defined by the claims.

Claims

Claims

1. Rotating electrical machine (1) comprising: - an electric motor (2), formed by a rotor (21) rotatable around a shaft (22) and a fixed stator (23) surrounding the rotor, extending along an axis (X), - a casing (11) surrounding the motor (2), - a cooling system (4) allowing the passage of a cooling liquid, and - an electronic assembly (3) mounted on the casing and comprising at least one heat sink (40) of the cooling system (4), characterized in that the cooling system comprises a first conduit (41) supplying the sink (40), the first conduit (41) being arranged at the casing (24) of the motor (2).

2. Electrical machine (1) according to claim 1, wherein the first conduit (41) is arranged perpendicular to the axis (X) of the shaft (22) and perpendicular to the heat sink (40).

3. Electrical machine (1) according to claim 1 or 2, in which the inlet (410) of the first conduit (41) is pressed against the casing (24).

4. Electrical machine (1) according to one of claims 1 to 3, in which the first conduit (41) forms a first elbow (411) directing the conduit towards the machine, then a second elbow (412) directing the conduit towards the dissipator (40).

5. Electrical machine (1) according to one of claims 1 to 4, in which the first conduit (31) opens into the dissipator (40).

6. An electrical machine (1) according to one of claims 1 to 5, wherein the first conduit (41) is fixed to the housing (24), for example the first conduit (41) is pressed and glued to the housing (24).

7. Electrical machine (1) according to one of claims 1 to 6, in which the cooling system comprises an additional conduit (43) acting as an outlet conduit, and a circular cooling circuit (44) of the motor (2) opening into this additional conduit (43).

8. Electrical machine (1) according to one of claims 1 to 6, in which the additional conduit (43) is arranged at the level of the casing (24) of the motor (2).

9. Electrical machine (1) according to one of claims 7 to 8, in which the additional conduit (43) is arranged parallel to the first conduit (31), pressed against the casing (24), and for example fixed, pressed and glued to the casing (24).

10. Motor vehicle comprising a rotating electrical machine (1) according to one of claims 1 to 9.

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