FR3062531A1 - ROTATING ELECTRIC MACHINE WITH SHUTTER LIMITING HOT AIR REBOUCLING - Google Patents

Abstract

The invention relates mainly to a rotating electrical machine (15) comprising: - a bearing (21), - a stator (18) mounted in the bearing (21), the stator (18) comprising a winding provided with phase outputs ( 26), - a heat sink (32) associated with an electronic power module (29) to which the phase outputs (26) are electrically connected, - a shutter (41) mounted between the bearing (21) and the heat sink ( 32), - characterized in that the shutter (41) comprises a body (48) and at least one set of petal (50) having at least one petal (51) foldable relative to the body (48), said at least a petal assembly (50) defining an opening (52) for passage of a phase output (26).

Description

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

O Extension request (s):

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

FR 3 062 531 - A1 ® ROTATING ELECTRIC MACHINE WITH HOT.

(57) The invention relates mainly to a rotary electric machine (15) comprising:

- a bearing (21),

- a stator (18) mounted in the bearing (21), the stator (18) comprising a winding provided with phase outputs (26),

- a heat sink (32) associated with an electronic power module (29) to which the phase outputs (26) are electrically connected,

- a shutter (41) mounted between the bearing (21) and the heat sink (32),

- characterized in that the shutter (41) comprises a body (48) and at least one set of petals (50) comprising at least one petal (51) foldable relative to the body (48), said at least one set of petal (50) defining an opening (52) for the passage of a phase output (26).

SHUTTER LIMITING AN AIR RECOUCLING

X; Y

------ 18

ROTATING ELECTRIC MACHINE PROVIDED WITH A SHUTTER LIMITING HOT AIR RECOUPLING

The invention relates to a rotary electrical machine provided with a shutter limiting a looping of hot air. The invention finds a particularly advantageous, but not exclusive, application with rotary electrical machines operating at least in alternator mode.

In a manner known per se, rotary electrical machines comprise a stator and a rotor secured to a shaft. The stator and the rotor are mounted in a casing configured to rotate the shaft on bearings by means of bearings. The rotor may be a claw rotor comprising two pole wheels and a core around which an excitation coil is wound. In another example, the rotor comprises a body formed by a stack of sheet 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 in triangle whose outputs are connected to an electronic power module comprising in particular a rectifier bridge in the case of an alternator. This rectifier bridge also works in an inverter mode in the case of an alternator-starter.

As illustrated in FIG. 1, in order to cool the electronic power module 1, a fan 2, fixed on the rotor 3 of the machine, makes it possible to create a current of air entering laterally via the arrow F1 inside of a passage defined by the face of the heat sink 4 facing the bearing 5 and the upper face of the bearing 5 facing the sink 4 and is then pushed laterally out of the electric machine according to arrow F2.

However, the air at the outlet of the fan 2 licks the winding bun 8 then the phase outlets 6 of the stator 7 and heats up. Part of this air is sucked in via axial vents 11 of the bearing in the machine according to arrow F3 instead of being discharged to the outside. Thus, the air temperature near the fins 9 of the dissipator 4 is higher, which decreases the cooling capacity of the machine.

It is known to mount a shutter 10 between the heat sink 4 and the bearing 5 in order to reduce the recirculation of hot air at the openings 11 for passage of the phase outputs 6. The shutter 10 may slightly overflow on the openings 11 while allowing the phase outputs to pass through 6. In such a configuration, the vents 11 for passing through the phases are closed at around 40%, which however does not prevent the phenomenon of hot air recirculation.

The invention aims to effectively remedy this drawback by proposing a rotary electric machine comprising:

- a step,

- a stator mounted in the bearing, the stator comprising a winding provided with phase outputs,

- a heat sink associated with an electronic power module to which the phase outputs are electrically connected, and

- a shutter mounted between the bearing and the heat sink, characterized in that the shutter comprises a body and at least one set of petals comprising at least one petal foldable relative to the body, said at least one set of petals delimiting an opening for the passage of a phase output.

The invention thus makes it possible, thanks to the configuration of the foldable petal or petals of the shutter, to plug substantially all of the hearing of the bearing. Thus, the air flow passing with the phase output through the hearing is almost nonexistent. This isolates the air inlet path from the cooling air outlet path, which avoids the appearance of the phenomenon of hot air recirculation towards the interior of the electric machine. In addition, having a foldable petal gives a certain flexibility to said petal, which guarantees easy insertion of the phase outputs through the shutter.

In one embodiment, the petal assembly has at least two petals.

According to one embodiment, two adjacent petals are separated from each other by a slot.

According to one embodiment, the petal is formed from an elastic material.

According to one embodiment, the petal is foldable along a groove located between the body and the corresponding petal.

According to one embodiment, the petal is in one piece with the body of the shutter.

According to one embodiment, the petal is molded onto the body of the shutter.

According to one embodiment, a thickness of the petal is less than a thickness of the body.

According to one embodiment, a petal has a first position in an unstressed state, that is to say in which no phase output passes through the opening, and a second position in a constrained state, that is to say in which a phase output passes through the opening.

According to one embodiment, in the unstressed state, the petal is located in a plane in which the body of the shutter extends.

According to one embodiment, in the unstressed state, the petal is inclined relative to a plane in which the body of the shutter extends.

According to one embodiment, the petal is formed of several portions of different inclination.

In one embodiment, the petal has a rim on the side of its free end extending, in the unstressed state, in a plane substantially parallel to the plane in which the body of the shutter extends.

According to one embodiment, the opening delimited by the petal assembly has a diameter greater than or equal to the diameter of the corresponding phase output.

According to one embodiment, the shutter comprises a stiffening rib located on the body around the petal.

According to one embodiment, the shutter comprises at least one wall positioned radially between the phase output and the bearing.

According to one embodiment, the shutter comprises at least one curved portion conforming to the shape of the bearing located between two consecutive phase exit passage openings.

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, already described, shows a partial sectional view of the rear part of a rotary electrical machine provided with a shutter according to the prior art;

2 shows a partial sectional view of the rear part of a rotary electric machine provided with a shutter according to an example of the present invention;

Figure 3a is a perspective view illustrating a first embodiment of the shutter according to the invention mounted on the rear bearing of the rotary electric machine;

Figure 3b is a detailed view of a set of petals of the shutter of Figure 3a;

Figure 3c shows an alternative embodiment of the shutter according to the invention provided with a stiffening rib;

Figure 4 is a perspective view illustrating a second embodiment of the shutter according to the present invention;

Figures 5a and 5b are perspective and side views illustrating a third embodiment of the shutter according to the present invention;

FIG. 5c is a partial side view illustrating an example of positioning of a wall for isolating the shutter according to the invention between the phase output and the bearing;

Figure 6 is a perspective view illustrating a fourth embodiment of the shutter according to the present invention;

FIG. 7 shows graphical representations of the evolution of the maximum acceptable current before the triggering of a thermal protection as a function of the speed of the rotary electrical machine respectively for a shutter according to the invention and a shutter according to the state of the 'art;

Figure 8 is a partial sectional view illustrating an example of positioning a petal relative to a phase output.

In FIGS. 2 to 8, identical, similar or similar elements retain the same reference from one figure to another.

FIG. 2 represents a sectional view of the rear of a rotary electrical machine 15 capable of operating reversibly in a generator mode to supply power to the battery and to the vehicle on-board network, and in an engine mode to supply mechanical power to the vehicle's thermal engine, in particular to ensure that it starts.

The rotary electrical machine 15 comprises a rotor 16 mounted on a shaft 17 of axis X and a stator 18 surrounding the rotor 16 with the presence of an air gap between the external periphery of the rotor 16 and the internal periphery of the stator 18. The shaft 17 is rotatably mounted relative to the rear bearing 21 comprising for this purpose a housing for a bearing 22. The stator 18 fixedly mounted in the bearing 21 is provided with an induced winding comprising a chignon 25 extending in axial projection relative to to a stator body. The winding further comprises phase outputs 26 which extend axially projecting from the bun.

These phase outputs 26 are electrically connected to an electronic power module 29, the electrical connection not being shown in the figures. The electronic power module 29 includes a rectifier and inverter bridge, for example with MOS type power transistors. In the example described here, this electronic power module 29 is mounted on the upper face of a heat sink 32, the upper face being the face axially opposite the face of said sink which is opposite the bearing 21. This module power electronics 29 is associated with an electronic control module 33. The power electronics module 29 and the dissipator 32 form a mezzanine above the landing 21. The mezzanine is fixed on the bearing 21 by means of fixing columns 34 visible in Figure 3a.

A protective cover 35 envelops the electronic power 29 and control 33 modules in order to protect them from the external environment.

In order to cool the electronic power module 29, a fan 38, fixed on the rotor 16 of the machine, makes it possible to create a current of air entering via the arrow F1 in the enclosure of the rotary electrical machine and leaving said enclosure. via arrow F2. In this exemplary embodiment, an air passage entering the enclosure is defined between the lower face of the dissipator 32 facing the bearing 21 and the upper face of said bearing 21 facing the said dissipator 32. In addition, the air leaving is discharged laterally outside the enclosure between a lower face of the bearing 21 and the fan 38. Fins 39 from the dissipator 32 may extend inside the incoming air passage, preferably in the direction of the level 21.

Alternatively, an air passage entering the enclosure could be defined between the upper face of the dissipator 32 facing the cover 35 and the lower face of the cover 35 facing the said dissipator 32. The fins 39 issuing from the dissipator could then extend towards the hood 35 and the power modules 29 and / or the control module 33 could extend between the dissipator 32 and the bearing 21.

Furthermore, a shutter 41 is mounted between the bearing 21 and the heat sink 32. More precisely here, the bearing 21 visible in FIG. 3a comprises a transverse flange 42 provided with a central housing 43 for the bearing 22 and gills 44 for the passage of air. The flange 42 is extended at its outer periphery by a flange 45 of axial orientation provided with lateral vents 47 for the passage of air and phase outputs 26 intended to be connected to the electronic power module 29. The shutter 41 is pressed against the face of the flange 42 facing the dissipator 32. Preferably, the shutter 41 of the Y axis is coaxial with the bearing of the X axis.

The shutter 41 makes it possible to isolate the flow of inlet air F1 from the flow of outlet air F2 so that the air leaving the rotary electrical machine 15 is not immediately reintroduced into said machine. This avoids significant recirculation of hot air from the interior of said machine.

To this end, the shutter 41 comprises a body 48 of generally annular shape and sets of petals 50 foldable relative to the body 48. Each set 50 delimits an opening 52 for the passage of a phase output 26. By the occurrence, the shutter 41 includes six sets of petals 50 to allow the passage of six phase outputs 26 in the case of a double three-phase type system. These six assemblies 50 are grouped into two series of three angularly spaced apart.

Of course, the number of sets of petals 50 as well as their positioning along the circumference of the stator depends on the configuration of the electric machine, in particular on its number of phases (3, 5, 6, or 7 in particular) and on the positioning connection lugs to the phase outputs 26 of the electronic power module 29.

More precisely in the first embodiment, as can be seen in FIG. 3b, each assembly 50 has four petals 51. The internal periphery of each petal 51 of the same assembly 50 delimits an opening 52 for the passage of a associated phase output. The opening 52 has a diameter L1, preferably greater than or equal to the diameter of said phase output 26.

Two adjacent petals 51 are separated from each other by a slot 55. In each assembly 50, there is thus a circumferential alternation of petals 51 and slots 55.

In order to allow a separation of the petals 51 during the insertion of the phase outlets 26 into a corresponding opening 52, each petal 51 is foldable along a groove 56 located between the body 48 and the corresponding petal 51. In other words, each groove 56 forms a thinned zone between the petal 51 and the body 48 along which the corresponding petal 51 can be folded. In addition, preferably, the thickness L3 of a petal 51 is less than the thickness L2 of the body 48. The thickness is defined in an axial direction.

In an exemplary embodiment, the opening 52 delimited by the petals 51 has a diameter L1 of the order of 4mm, the body 48 has a thickness L2 of the order of 1mm, each petal 51 has a thickness L3 of the around 0.5mm, while the thickness L4 of the grooved area is around 0.3mm.

The petals 51 are here in one piece with the body 48 of the shutter 41, that is to say that they are made in one piece with the body 48, for example during a molding operation. For example, the body 48 and the petals 51 are then entirely formed from the same plastic. The plastic used can be more or less flexible, for example PA66 can be used.

As a variant, the petals 51 could be overmolded on the body 48 of the shutter 41. In this example, the body 48 is formed of a plastic material and the petals can be formed of an elastic material such as rubber.

In the example shown, two adjacent petals 51 extend along two edges 58, 59 of the body 48 forming a non-zero angle with respect to each other so as to have a V shape. The other two petals 51 extend along edges 60, 61 substantially parallel to one another and situated respectively in the extension of edge 58 and edge 59. As a variant, the petals 51 may extend along edges delimiting, a square, rectangle, circle, semicircle, or any other shape suitable for the application.

According to an alternative embodiment shown in Figure 3c, the shutter 41 may include a stiffening rib 64 located around the petals 51 and along the edges 58, 59, 60, 61. This rib 64 allows a stiffening of the shutter 41 .

In the embodiment of Figure 4, the shutter 41 further comprises curved portions 67 matching the shape of the bearing 21. There is a circumferential alternation between the curved portions 67 and the sets of 50 petals consecutive. Walls 68 provide the connection between the parallel edges 60, 61 carrying the petals 51 and the corresponding curved portions 67. The curved portions 67 make it possible to facilitate the positioning of the shutter 41 by forming a positioning guide for said shutter on the bearing 21.

In an exemplary embodiment, a petal may be in a first state, called an unstressed state, that is to say when there is no phase output 26 through the opening 52, or in a second state, called a constrained state, that is to say when a phase output 26 passes through the opening 52. As illustrated in FIG. 8, once the phase output 26 is inserted in the opening 52, the latter can constrain the petal 51 and lead it into a second state in which it is in a position different from its position in the unconstrained state.

In the example of FIGS. 3a, 3b, 3c and 4, in the unstressed state, the petals 51 lie in a plane P in which the body 48 of the shutter 41 extends.

Alternatively, in the embodiment shown in Figures 5a, 5b, and 5c, in the unstressed state, the petals 51 are inclined relative to a plane P in which extends the body 48 of the shutter 41 of so as to present a pyramid shape. The petals may for example form an angle of inclination A1 of the order of 45 degrees relative to the plane P in which the body 48 extends.

Each petal 51 can be formed of several portions. In the embodiment shown in Figures 5a, 5b and 5c, each petal 51 has an inclined portion 69 and a flange 70. The inclined portion 69 extends between the body 48 and the flange 70 and said flange extends on the side of the free end of the petal 51. These flanges 70 delimit the opening 52 for passage of a phase outlet 26. Also in this example, the flange 70 extends, in the unstressed state, in a plane substantially parallel to plane P in which extends the body 48 of the shutter 41. In an alternative embodiment not shown, a petal may include several portions of different inclination in order to form the shape of a pyramid.

This pyramid shape makes it easier to insert the phase output 26 through the opening 52 by creating a guide for said phase output.

In addition, a wall 71 extends in axial projection relative to the annular body 48 in the direction opposite to that of the petals 51. This wall 71 is intended to be positioned radially between the phase outputs 26 and the bearing 21, such that this is shown in Figure 5c. The wall 71 here delimits a shape in an arc of a circle along the circumference of the bearing 21. This wall 71 makes it possible to reinforce the electrical insulation between the bearing 21 which is generally at ground potential and the phase output 26. In particular the low wall 71 avoids the creation of a salt bridge.

In an alternative embodiment not shown, a wall may also extend in axial projection relative to the body 48 in the direction of the dissipator 32. This wall then makes it possible to improve the reduction in the recirculation of hot air in the enclosure of the rotating electric machine.

In the embodiment of Figure 6, each set of petals 50 has more than four petals. The number of petals may thus vary between a minimum of one petal and a maximum of ten petals. In addition, the shutter 41 comprises only three sets of petals 50 so as to be able to adapt to a three-phase system.

FIG. 7 highlights the maximum acceptable current gain before the triggering of a thermal protection of the machine for a shutter 41 according to the invention blocking the entire portion of the hearing 47 allowing the passage of an outlet from phase 26 (cf. curve C1) compared to a state of the art shutter blocking 40% of the part of the hearing 47 authorizing the passage of a corresponding phase 26 output (cf. curve C2). This current gain is greater than 15A for rotational speeds greater than 2200 rpm.

In all embodiments, the shutter 41 may further comprise damping elements 74 intended to come into abutment against the opposite face of the dissipator 32. These damping elements 74 are formed for example for a wall in elevation relative to the rest of the body 48.

The shutter 41 may also include notches 75 allowing the passage of the fixing columns 34 of the mezzanine, as shown in FIG. 3a.

In addition, it will also be possible to provide guide devices 76 for wires, in particular from sensors, on the shutter 41.

The shutter 41 which has just been described can generally be implemented in any type of alternator, in particular comprising a rotor with claws or with salient poles.

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. For example, it will not depart from the scope of the invention to propose a rotary electrical machine whose position of the bearing and that of the assembly formed by the heat sink and the electronic power module are axially reversed, that is to say - say by proposing a machine in which the electronic assembly is integrated in the bearing.

Furthermore, the different 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 (14)

1. Rotating electric machine (15) comprising: - a bearing (21), - a stator (18) mounted in the bearing (21), the stator (18) comprising a winding provided with phase outputs (26), a heat sink (32) associated with an electronic power module (29) to which the phase outputs (26) are electrically connected, and - a shutter (41) mounted between the bearing (21) and the heat sink (32), characterized in that the shutter (41) comprises a body (48) and at least one set of petals (50) comprising at least a petal (51) foldable relative to the body (48), said at least one set of petal (50) delimiting an opening (52) for the passage of a phase output (26). 2. Rotating electric machine according to claim 1, characterized in that the petal assembly (50) comprises at least two petals (51). 3. Rotating electric machine according to claim 1 or 2, characterized in that the petal (51) is formed of an elastic material. 4. Rotating electric machine according to any one of claims 1 to 3, characterized in that the petal (51) is foldable along a groove (56) located between the body (48) and the petal (51) corresponding. 5. Rotating electric machine according to any one of claims 1 to 4, characterized in that a thickness (L3) of the petal (51) is less than a thickness (L2) of the body (48). 6. rotary electrical machine according to any one of claims 1 to 4, characterized in that a petal (51) has a first position in an unstressed state, that is to say in which no phase output ( 26) passes through the opening (52), and a second position in a constrained state, that is to say in which a phase output (26) passes through the opening (52). 7. rotary electric machine according to claim 6, characterized in that in the unstressed state the petal (51) is located in a plane (P) in which extends the body (48) of the shutter (41 ). 8. rotary electric machine according to claim 6, characterized in that in the unstressed state the petal (51) is inclined relative to a plane (P) in which extends the body (48) of the shutter (41). 9. Rotating electric machine according to any one of claims 1 to 8, characterized in that the petal is formed of several portions of different inclination. 10. Rotating electric machine according to claim 9, characterized in that the petal (51) has a flange (70) on the side of its free end extending, in the unstressed state, in a plane substantially parallel to the plane ( P) in which extends the body (48) of the shutter (41). 11. rotary electric machine according to any one of claims 1 to 10, characterized in that the opening (52) delimited by the petal assembly (50) has a diameter (L1) greater than or equal to the diameter of the outlet corresponding phase (26). 12. Rotating electric machine according to any one of claims 1 to 11, characterized in that the shutter (41) has a stiffening rib (64) located on the body (48) around the petal (51). 13. rotary electric machine according to any one of claims 1 to 12, characterized in that the shutter (41) comprises at least one wall (71) positioned radially between the phase output (26) and the bearing (21) . 14. rotary electric machine according to any one of claims 1 to 13, characterized in that the shutter (41) comprises at least one curved portion (67) matching the shape of the bearing (21) located between two openings (52) consecutive phase output passage (26). 1/6 STATE OF THE ART