Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K5/00—Casings; Enclosures; Supports
  • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
  • H02K5/20—Casings or enclosures characterised by the shape, form or construction thereof with channels or ducts for flow of cooling medium
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K9/00—Arrangements for cooling or ventilating
  • H02K9/19—Arrangements for cooling or ventilating for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil
  • H02K9/197—Arrangements for cooling or ventilating for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil in which the rotor or stator space is fluid-tight, e.g. to provide for different cooling media for rotor and stator

Definitions

• the present invention relates to a cooling chamber for a rotating electrical machine, as well as to a rotating electrical machine comprising such a cooling chamber.
• the electric machine is for example an alternator or an alternator-starter supplied by a nominal voltage of 12V or 48V, or even more, or an electric motor.
• This electric machine can be integrated into a vehicle with hybrid or purely electric propulsion, for example an automobile.
• This type of rotating electrical machine can be cooled by convection by means of fans mounted on the rotor and allowing an air flow to circulate, in particular through the stator.
• This type of cooling is particularly effective when the machine is running at high speed. This is because the faster the rotor turns, the more air the fan can stir. However, this type of cooling may not be sufficient when the machine is operating at low rotational speed. In addition, air cooling is limited by the size of the fan which must fit into a small footprint.
• the invention aims to meet this need and it achieves this, in one of its aspects, using a rotating electrical machine, comprising:
• a cooling chamber disposed radially around the stator and delimited between a radially inner wall and a radially outer wall, of the liquid circulating in this chamber between a liquid inlet in the chamber and a liquid outlet in the chamber, this liquid inlet and this liquid outlet being angularly offset with respect to the axis of rotation of the rotor, at least one of the radial wall ement interior and of the radially exterior wall bearing at least one relief projecting radially in the cooling chamber in the direction of the other of the radially interior wall and of the radially exterior wall, without reaching this other wall.
• the radial projection defined by the wall corresponds to a local reduction in the radial dimension of the cooling chamber.
• the relief carried by one wall does not extend into the chamber to the other wall, so that this relief does not establish a seal. It is thus not necessary to ensure that the dimension chains of the parts making this chamber will be able to obtain this seal. Furthermore, it may prove advantageous to permanently provide a pressure drop between the liquid inlet and the liquid outlet via the leak existing in the chamber at the level of the relief.
• Rotor axis refers to the axis of rotation of the rotating electrical machine.
• the relief can be made in one piece with the wall bearing said relief and partly delimiting the chamber.
• This wall and this relief are for example made by molding.
• the wall bearing the relief belongs, for example, to one of the bearings of the electrical machine, in which case the relief angle of the relief may be the same as that of the bearing.
• the relief may have a crenellated shape in a plane perpendicular to the axis of rotation.
• the two end edges angularly speaking of this relief can thus be parallel. Alternatively, these two end edges are not parallel.
• the angular dimension of the relief, measured from the axis of rotation of the machine between its two end edges angularly speaking, can be between 0 ° and 180 °.
• Each of the radially inner wall of the chamber and of the radially outer wall of the chamber may be cylindrical over all or part of its angular periphery.
• the cooling chamber may or may not maintain a constant radial dimension over its entire angular periphery.
• the cooling chamber can be sealed at each of its axial ends by a seal.
• the radially inner wall of the chamber may bear at least one first relief projecting radially in the cooling chamber in the direction of the radially outer wall without reaching this radially outer wall, and the radially outer wall of the chamber may bear at least a second relief projecting radially in the cooling chamber in the direction of the radially inner wall without reaching this radially inner wall.
• first and second reliefs the latter can be arranged so that one encounters an alternation of first relief (s) and second relief (s) when one is standing. angularly moves in the cooling chamber. In other words, there is a path when one moves angularly in the cooling chamber according to which one does not meet consecutively two reliefs of the same type, that is to say two first reliefs or two second reliefs.
• the overall number of reliefs may depend on the angle between the liquid inlet and the liquid outlet in the cooling chamber, this angle being measured from the axis of rotation. The more this angle increases, the more this overall number can increase. This angle can take any value between 180 ° and 360 °, for example a value between 270 ° and 360 °, for example a value between 270 ° and 350 °.
• Alternating a first relief with a second relief can provide a baffle for the liquid seeking to circulate in the cooling chamber between the liquid inlet and the liquid outlet. This baffle determines the leakage rate through the reliefs.
• the leakage rate may be less than 25%, in particular 10%, in particular less than 5%, in particular less than 1%, of the liquid flow rate at the level of the liquid inlet in the cooling chamber.
• first (s) and second (s) reliefs can be chosen to act on the distribution of the liquid in the cooling chamber around the periphery of the stator between:
• All of the aforementioned reliefs can be exclusively located in the same fraction of the cooling chamber defined between the liquid inlet and the liquid outlet.
• the liquid entering the chamber through the liquid inlet can reach the liquid outlet: either by paths crossing all the reliefs, or by paths not crossing any.
• the number of first reliefs may be equal to the number of second reliefs, being in particular equal to one or two, or more. As a variant, the number of first reliefs may not be equal to the number of second reliefs, being greater or less than the number of second reliefs.
• a first, respectively second, relief can for example be associated with two second, respectively first, reliefs.
• Each first relief can have the same radial dimension as each second relief.
• each first relief may have a radial dimension greater than the radial dimension of each second relief, or the reverse.
• the radial dimension of a first relief and the radial dimension of a second relief directly adjacent angularly speaking can be chosen so that this first and this second relief overlap radially over at least 20% of the radial dimension of the chamber cooling.
• Each first relief can have the same angular dimension as each second relief.
• each second relief may have an angular dimension greater than the angular dimension of each first relief, or the reverse.
• each first relief has a radial dimension greater than the radial dimension of each second relief, and each first relief has an angular dimension less than the angular dimension of each second relief.
• all of these first reliefs may or may not have the same shape between them.
• all of these second reliefs may or may not have the same shape between them.
• each relief may extend over at least 60% of the axial dimension of the cooling chamber, in particular 90%.
• Each relief extends, for example, over at most 99% of the axial dimension of the cooling chamber, and in particular over at least 90% of this axial dimension.
• One or more axial ends of the chamber may be devoid of relief, making it easier for this end to cooperate with a seal.
• Each relief does not necessarily extend over the entire height of the cooling chamber.
• the rotating electrical machine is for example a synchronous machine, for example a three-phase synchronous machine or a synchronous machine whose electric stator winding defines a double three-phase system.
• the electric stator winding is for example formed by wires or by conductive bars connected to each other.
• the rotor can be a claw rotor. As a variant or in addition, it can be a rotor with permanent magnets.
• This rotor then comprises a first and a second nested pole wheel, the first pole wheel defining a series of claws of generally trapezoidal shape, each claw extending axially towards the second pole wheel, the second pole wheel defining a series of generally trapezoidal shaped claws, each claw extending axially towards the first pole wheel.
• a permanent magnet can be received between two consecutive claws circumferentially speaking for the rotor.
• the rotor may be other than a claw rotor, comprising for example a pack of sheets or being a cage rotor.
• the rotor can include any number of pole pairs, for example six or eight pole pairs.
• the rotating electric machine may have a rated electric power of 4 kW, 8 kW, 15 kW, 25 kW or more.
• This rotating electric machine can be supplied electrically from an electric energy storage unit via an inverter / rectifier, this inverter / rectifier making it possible, depending on whether the electric machine operates as a motor or as a generator, to charge an on-board network of the vehicle or to be electrically supplied from this network.
• the nominal voltage of the electrical energy storage unit can be 12 V, 48 V or some other value, for example another value greater than 300 V.
• the rotating electric machine can also include a pulley or any other means of connection to the rest of the vehicle's powertrain, such as a gear.
• the electric machine is for example connected, in particular via a belt, to the crankshaft of the heat engine of the vehicle.
• the electric machine is connected to other locations of the powertrain, for example to the input of the gearbox from the point of view of the torque passing through to the wheels of the vehicle, at the output of the gearbox at the point view of the torque passing through the wheels of the vehicle, at the level of the gearbox from the point of view of the torque passing through the wheels of the vehicle, or even on the front axle or the rear axle of this powertrain.
• the rotating electric machine is not necessarily a synchronous machine, it can be an asynchronous machine.
• the liquid can be water or any other coolant, for example that used to cool the heat engine of the vehicle when the vehicle is a hybrid vehicle.
• the cooling chamber can only cool the rotating electrical machine, without also cooling the inverter / rectifier associated with the electrical machine.
• This inverter / rectifier can be cooled otherwise, for example by another liquid or by air.
• the room of cooling may be in fluid communication with another cooling chamber making it possible to cool the inverter / rectifier.
• These two cooling chambers can be traversed by the same liquid.
• This other cooling chamber can be a channel integrated in the heat sink on which the electronic components of the inverter / rectifier are mounted.
• This channel integrated in the heat sink can be produced by molding or extrusion of material after production of the heat sink.
• This further cooling chamber may have a substantially circular or U-shaped shape, when viewed along the axis of rotation.
• the radially inner wall of the chamber may belong to an axial skirt of a first bearing, this first bearing also comprising a transverse wall extending radially.
• the radially outer wall of the chamber may belong to an axial skirt of a second bearing, this second bearing also comprising a transverse wall extending radially.
• These two transverse walls can axially delimit the housing in which the stator and the rotor of the electric machine are received.
• Each of these bearings can carry a bearing for the rotational mounting of the shaft of the rotating electrical machine. This is, for example, a ball bearing or a cage bearing.
• the aforementioned heat sink can be mounted on one of the aforementioned transverse walls.
• FIG. 1 shows schematically and in axial section an example of a rotating electrical machine to which the invention can be applied
• FIG. 2 shows a cooling chamber of the machine of Figure 1 according to the prior art
• FIG. 3 shows in detail the reliefs projecting into the cooling chamber of a rotating electrical machine similar to that of Figure 1, according to an exemplary implementation of the invention.
• FIG. 1 shows a polyphase rotary electrical machine 10, in particular for a motor vehicle, to which the invention can be applied.
• This rotating electric machine can form an alternator or an alternator-starter of the vehicle or an electric motor of the vehicle.
• This rotary electrical machine can be supplied via power electronics 24 comprising an inverter / rectifier by a battery whose nominal voltage is 12 V or 48 V or of a value greater than 300 V, for example.
• the rotary electrical machine 10 comprises a casing 11. Inside this casing 11, it further comprises a shaft 13, a rotor 12 integral in rotation with the shaft 13 and a stator 15 surrounding the rotor 12.
• the rotary electric machine 10 comprises a casing 11. Rotational movement of the rotor 12 takes place around an X axis.
• the housing 11 has a front bearing 16 and a rear bearing 17 which are assembled together. These bearings 16, 17 are of hollow shape and each carry a respective ball bearing 18, 19 centrally for the rotational mounting of the shaft 13.
• the housing 11 comprises fixing means, not shown, allowing mounting the rotary electric machine 10 in the vehicle.
• a pulley is fixed to a front end 14 of the shaft 13, at the level of the front bearing 16, for example using a nut resting on the bottom of the cavity of this pulley.
• This pulley makes it possible to transmit the rotational movement to the shaft 13 or to the shaft 13 to transmit its rotational movement to the belt.
• the upper and lower denominations as well as above / below or even front / rear refer to the pulley.
• an upper or top or front face being a face oriented in the direction of the pulley while a lower or bottom or rear face being a face oriented in the opposite direction of the pulley.
• the rear end of the shaft 13 here carries slip rings 21 belonging to a collector. Brushes belonging to a brush holder, not shown, are arranged so as to rub on the slip rings 21.
• the brush holder is connected to a voltage regulator, not shown, forming part of the power electronics 24 already mentioned. .
• the power electronics 24 also include an inverter / rectifier connected on the one hand to the phases of the stator and on the other hand to the on-board network of the vehicle.
• the inverter / rectifier comprises switches such as transistors as well as other electronic components, and these electronic components 11 are cooled via a heat sink 23.
• the power electronics 24 is mounted on an axial end. of the machine 10 and in particular its rear axial end.
• the heat sink 23 is mounted on the rear bearing 17 by means of fixing devices which are for example screws or tie rods.
• rotor 12 is a claw rotor. It comprises two pole wheels 31. Each pole wheel 31 is formed by a plate 32 and a plurality of claws 33 forming magnetic poles.
• the plate 32 is of transverse orientation and has, for example, a substantially annular shape.
• This rotor 12 further comprises a cylindrical core 34 which is interposed axially between the pole wheels 31.
• this core 34 is formed of two half-cores each belonging to one of the pole wheels.
• the rotor 12 comprises, between the core 34 and the claws 33, a coil 35 comprising, here, a winding hub and an electrical winding on this hub.
• the slip rings 21 belonging to the collector are connected by wire connections to said coil 35.
• the rotor 12 may also include permanent magnets 20 interposed between two adjacent claws 33. In the section of FIG. 1, the claws are only partially shown in the profile of the magnets 20.
• the invention is not, however, limited to a claw rotor, the rotor possibly being formed using a bundle of sheets, for example being a rotor with permanent magnets.
• the stator 15 comprises a body 27 in the form of a bundle of sheets provided with notches, for example of the semi-closed or open type, equipped with insulating notches for mounting an electrical winding. 28.
• This coil 28 passes through the notches of the body 27 and form a front chignon 29 and a rear chignon 30 on either side of the body of the stator.
• the coil 28 is connected, for example, in star or in delta.
• the coil 28 is formed of one or more phases. Each phase comprises at least one conductor passing through the notches of the stator body 27 and forms, with all the phases, the buns.
• the coil 28 is electrically connected to the aforementioned power electronics 24.
• the machine 10 also comprises convection cooling means to further improve the cooling of the stator and that of the rotor.
• the rotor has a single fan 25 and the bearings 16, 17 each have substantially lateral openings for the passage of the air generated by the rotation of the fan.
• the machine can include two fans each mounted at one end of the rotor.
• the rotating electrical machine 10 is cooled mainly by means of a cooling circuit 37 allowing a liquid to flow inside the machine.
• the liquid is in this case coolant also used to cool the heat engine.
• any other liquid can be used, for example water.
• the cooling circuit 37 of the example considered will now be described. This cooling circuit successively cools the power electronics 24 and the rotating electrical machine 10.
• the invention is not limited thereto, however, separate circuits can be provided, for the power electronics 24 on the one hand and for the rotating electric machine 10 on the other hand.
• the circuit 37 comprises an inlet made in the heat sink 23 and opening into a cooling chamber 39 of the power electronics 24. Once the liquid has circulated in this chamber 39, the liquid s' flows towards a cooling chamber 40 of the rotary electrical machine 10 which it gains via a liquid inlet 61 and which it leaves via a liquid outlet 62.
• the liquid outlet 62 is connected to an outlet of the cooling circuit.
• This liquid inlet 61 and this liquid outlet 62 are angularly offset.
• This cooling chamber 40 is here delimited by the front bearing 16 and the rear bearing 17.
• the cooling chamber 39 of the power electronics 24 can be integrated into the heat sink 23, that is to say that this chamber 39 can be produced during molding or molding. machining of said heat sink to define a hollow volume inside thereof.
• the junction between the cooling chamber 39 and the cooling chamber 40 can be effected by means of a channel comprising several portions successively referenced 63, 64 and 65 in Figure 1.
• the cooling chamber 40 may be formed in the housing 11.
• the front bearing 16 comprises a transverse wall provided at its center with a projecting nose having an internal periphery carrying the front bearing. 18 and delimiting an opening for the passage of the shaft 13.
• the front bearing 16 further comprises a skirt 47 projecting from an outer periphery of the transverse wall.
• the skirt 47 has an annular shape of axial orientation extending towards the rear bearing 17.
• the rear bearing 17 comprises a transverse wall provided at its center with the housing for receiving the rear bearing 19.
• the rear bearing 17 also comprises a skirt 50 coming from the outer periphery of the transverse wall. This skirt 50 has an annular shape of axial orientation.
• the stator body 27 is for example mounted shrunk inside the front bearing 16 so as to establish intimate contact between the outer periphery of the stator body and the inner periphery of the skirt 47 of the front bearing 16.
• the stator is first mounted in the front bearing 16 then the rear bearing 17 is assembled on the front bearing 16 by means of an assembly device 26, in particular screws or tie rods.
• skirts are directed axially towards one another and fit into one another, such that the outer periphery 70 of the skirt 47 of the front flange 16 and the inner periphery 71 of the skirt 50 of the rear flange 17 delimit the chamber 40.
• the skirt 47 thus defines the radially inner wall 70 of the chamber 40 and the skirt 50 defines the radially outer wall 71 of the chamber 40.
• Each of these walls 70 and 71 is here cylindrical all around of the X axis, so that the chamber 40 is in this example in the form of an annular space whose axis is the X axis.
• This chamber 40 here surrounds the stator 15.
• the chamber 40 may include, at its axial ends, seals 57. These are for example O-rings.
• the cooling chamber 40 comprises a wall 60 making it possible to seal off the liquid inlet 61 from the liquid outlet 62 of said chamber.
• This wall 60 projects radially into the chamber 40 so as to close the latter.
• a plurality of reliefs projecting radially into the cooling chamber 40 without closing the latter is present. These reliefs are here produced in a single piece by molding with the wall 70, 71 carrying them. Each relief causes a local reduction in the radial dimension of the cooling chamber 40.
• a first relief 73 projects radially into the cooling chamber 40 from the radially inner wall 70 in the direction of the radially outer wall 71 without reaching this radially outer wall 71.
• a second relief 74 is present, and this second relief 74 is carried by the radially outer wall 71 of the chamber 40 and this second relief 74 projects radially into the cooling chamber 40 in the direction of the radially inner wall 70 without reaching this radially inner wall 70.
• These reliefs 73 and 74 are here arranged in the angular portion of the channel disposed between the liquid inlet 61 and the liquid outlet 62.
• Each relief 73, 74 can, as can be seen in Figure 3, have a crenellated shape in a plane perpendicular to the X axis.
• the two end walls 78 angularly speaking of the relief can thus be parallel.
• the angular dimension of each relief measured from the axis of rotation of the machine between its two end edges angularly speaking, can be between 0 and 180 °, being for example between 5 ° and 10 °, or between 10 ° and 20 °, or between 10 ° and 40 °, in particular.
• first relief 73 has a radial dimension greater than the radial dimension of the second relief 74 and that the first relief 73 has an angular dimension less than the angular dimension of the second relief 74.
• the radial dimension of the reliefs 73 and 74 is such that the latter overlap radially over at least 20% of the radial dimension of the chamber 40.
• Each relief 73, 74 is not necessarily provided over the entire axial dimension of the cooling chamber 40, for example not being provided at the level of at least one axial end of this chamber 40.
• the number of reliefs 73, 74 can be different.
• three reliefs can be provided, for example a first relief 73 and two second reliefs 74, or conversely two first reliefs 73 and a second relief 74.
• four reliefs can be provided, for example two first reliefs 73 and two second reliefs 74.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Motor Or Generator Cooling System (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=70228271

Family Applications (1)

Country Status (3)

Family Cites Families (9)

• 2020
  • 2020-02-03 FR FR2001070A patent/FR3106942B1/fr active Active
• 2021
  • 2021-01-15 EP EP21700311.0A patent/EP4101057A1/de active Pending
  • 2021-01-15 WO PCT/EP2021/050797 patent/WO2021156039A1/fr unknown

Also Published As

Similar Documents

Legal Events