FR3062531B1 - 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

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

In known manner, the rotating electrical machines comprise a stator and a rotor secured to a shaft. The stator and the rotor are mounted in a housing configured to rotate the shaft on bearings through bearings. The rotor may be a claw rotor having two pole wheels and a core around which is wound an excitation coil. In another example, the rotor comprises a body formed by a stack of sheets of sheets held in pack form by means of a suitable fastening system. The rotor comprises poles formed for example by permanent magnets housed in cavities formed in the magnetic mass of the rotor. Alternatively, in a so-called "salient" poles architecture, the poles are formed by coils wound around rotor arms.

Furthermore, the stator comprises a body consisting of a stack of thin sheets forming a ring, whose inner face is provided with notches open inwardly to receive phase windings. These windings pass through the notches of the stator body and form buns protruding from both sides 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 delta whose outputs are connected to an electronic power module including a rectifier bridge in the case of an alternator. This bridge rectifier also operates 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 stream of air entering laterally via the arrow F1 inside. 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 heat sink 4 and is discharged laterally outwardly of the electric machine according to the arrow F2.

However, the air at the outlet of the fan 2 licks the winding bun 8 and the phase outputs 6 of the stator 7 and heats up. Part of this air is sucked back via axial louvers 11 of the bearing in the machine according to the arrow F3 instead of escaping to the outside. Thus, the air temperature near the fins 9 of the heatsink 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 to reduce the looping of hot air at the louvers 11 passage of the phase outputs 6. The shutter 10 may overflow slightly on the gills 11 while leaving the phase outputs 6. In such a configuration, the gills 11 phase passage are closed at about 40%, which however does not prevent the hot air looping phenomenon. The invention aims to effectively remedy this disadvantage by proposing a rotating electrical machine comprising: - a bearing, - a stator mounted in the bearing, the stator comprising a winding provided with phase outputs, - a heat sink associated with an electronic module of power 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 petal assembly comprising at least one foldable petal with respect to the body, said at least one petal assembly defining an opening for passage of a phase output. The invention thus makes it possible, thanks to the configuration of the foldable petal (s) of the shutter, to substantially seal off the entire hearing of the bearing. Thus, the flow of air passing with the phase output through the hearing is virtually nonexistent. This isolates the air inlet path with respect to the cooling air outlet path, which prevents the occurrence of the phenomenon of hot air loopback to the interior of the electric machine. In addition, having a foldable petal gives a certain flexibility to said petal, which makes it possible to guarantee easy insertion of the phase outputs through the shutter.

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

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

In one embodiment, the petal is formed of an elastic material.

In one embodiment, the petal is foldable in a groove between the body and the corresponding petal.

In one embodiment, the petal is integral with the body of the shutter.

In one embodiment, the petal is overmolded on the body of the shutter.

In 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 unconstrained 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 wherein a phase output passes through the opening.

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

According to one embodiment, in the unconstrained state, the petal is inclined with respect to a plane in which the body of the shutter extends.

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

According to 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.

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

In one embodiment, the shutter has 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 apertures. The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given for illustrative but not limiting of the invention.

Figure 1, already described, shows a partial sectional view of the rear part of a rotary electric machine provided with a shutter according to the state of the art;

Figure 2 shows a partial sectional view of the rear portion of a rotating 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 rotating electrical machine;

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

FIG. 3c represents an alternative embodiment of the shutter according to the invention provided with a stiffening rib;

Fig. 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;

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

Fig. 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 rotating 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 with respect 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 is a cross-sectional view of the rear of a rotating electrical machine 15 operable reversibly in a generator mode to provide power to the battery and the vehicle's onboard network, and in a motor mode to provide mechanical power to the engine of the vehicle to ensure its startup.

The rotating 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 outer periphery of the rotor 16 and the inner periphery of the stator 18. The shaft 17 is rotatably mounted with respect 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 coil comprising a bun 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 is not shown in the figures. The electronic power module 29 comprises 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 opposite face axially to the face of said dissipator which is opposite the bearing 21. This module power electronics 29 is associated with an electronic control module 33. The electronic power module 29 and the dissipator 32 form a mezzanine above the bearing 21. The mezzanine is fixed on the bearing 21 by means of visible fixing columns 34 in Figure 3a.

A protective cover 35 envelopes the power electronic modules 29 and control 33 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 stream of air entering via the arrow F1 into the enclosure of the rotating electrical machine and leaving said enclosure via the arrow F2. In this embodiment, an air passage entering the chamber is defined between the lower face of the dissipator 32 facing the bearing 21 and the upper face of said bearing 21 facing said dissipator 32. In addition, the outgoing air is discharged laterally outside the enclosure between a lower face of the bearing 21 and the fan 38. The fins 39 from the dissipator 32 may extend inside the air passage entering, preferably towards the landing 21.

Alternatively, an air passage entering the chamber could be defined between the upper face of the dissipator 32 facing the cover 35 and the underside of the cover 35 facing said dissipator 32. The fins 39 from the heatsink could then s' extend towards the cover 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 Figure 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 an axially oriented flange 45 provided with lateral openings 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 Y axis is coaxial with the X axis bearing. The shutter 41 isolates the air flow of F1 input with respect to the outlet air flow F2 so that the air leaving the rotating electrical machine 15 is not reintroduced immediately into said machine. This avoids a large recirculation of hot air from inside said machine. For this purpose, the shutter 41 comprises a body 48 of generally annular shape and petal assemblies 50 foldable relative to the body 48. Each assembly 50 defines an opening 52 for the passage of a phase outlet 26. In the In this case, the shutter 41 has six sets of petals 50 to allow the passage of six phase outputs 26 in the case of a three-phase type double system. These six sets 50 are grouped into two sets of three angularly spaced apart.

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

More specifically in the first embodiment, as can be seen in Figure 3b, each set 50 has four petals 51. The inner periphery of each petal 51 of the same set 50 defines 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 set 50, there is thus a circumferential alternation of petals 51 and slots 55.

In order to allow spacing of the petals 51 during insertion of the phase outputs 26 into a corresponding opening 52, each petal 51 is foldable along a groove 56 located between the body 48 and the petal 51 corresponding. In other words, each groove 56 forms a thinned zone between the petal 51 and the body 48 according to 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 4 mm, the body 48 has a thickness L 2 of the order of 1 mm, each petal 51 has a thickness L 3 of the order of 0.5mm, while the thickness L4 of the grooved area is of the order of 0.3mm.

The petals 51 are here in one piece with the body 48 of the shutter 41, that is to say 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 of the same plastic material. The plastic material used may be more or less flexible, for example PA66 may be used.

Alternatively, the petals 51 may 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 may 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 each other and respectively located in the extension of the edge 58 and the edge 59. Alternatively, the petals 51 may extend along delimiting edges, a square, a rectangle, a circle, a semicircle, or any other form suitable for the application.

According to an alternative embodiment shown in Figure 3c, the shutter 41 may comprise 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 conforming to the shape of the bearing 21. There is a circumferential alternation between the curved portions 67 and the petal sets 50 consecutively. 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 makes it easier to position the shutter 41 by forming a guide for positioning said shutter on the bearing 21.

In an exemplary embodiment, a petal may be in a first state, said unconstrained state, that is to say when there is no phase output 26 through the opening 52, or in a second state, said 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 has been inserted in the opening 52, that it can constrain the petal 51 and lead it into a second state in which it is in a position different from its position of the unconstrained state.

In the example of FIGS. 3a, 3b, 3c and 4, in the unconstrained 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 FIGS. 5a, 5b, and 5c, in the unconstrained state, the petals 51 are inclined with respect to a plane P in which the body 48 of the shutter 41 extends. way to present a pyramid shape. The petals may for example form an inclination angle A1 of the order of 45 degrees relative to the plane P in which the body 48 extends.

Each petal 51 may 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 free end side of the petal 51. These flanges 70 delimit the opening 52 for passage of a phase outlet 26. In this example, the flange 70 extends, in the unconstrained state, into a plane substantially parallel to the plane P in which the body 48 of the shutter 41 extends. In an embodiment variant not shown, a petal may comprise several portions of different inclination in order to form the pyramid shape.

This pyramid shape facilitates the insertion of the phase output 26 through the opening 52 by creating a guide of said phase output.

In addition, a wall 71 extends in axial projection relative to the annular body 48 in the opposite direction to that of the petals 51. This wall 71 is intended to be positioned radially between the phase outputs 26 and the bearing 21, as shown in FIG. this is shown in Figure 5c. The wall 71 delimits here an arcuate shape along the circumference of the bearing 21. This wall 71 reinforces the electrical insulation between the bearing 21 which is generally at a ground potential and the phase output 26. In particular the 71 wall avoids the creation of 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 of 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 can vary between a minimum petal and a dozen petals at most. In addition, the shutter 41 comprises only three sets of petals 50 so as to adapt to a three-phase system.

FIG. 7 shows the maximum acceptable current gain before triggering a thermal protection of the machine for a shutter 41 according to the invention that closes the entire portion of the hearing 47 allowing the passage of an output of phase 26 (see curve C1) with respect to a shutter of the state of the art plugging 40% of the part of the hearing 47 allowing the passage of a corresponding phase output 26 (see curve C2). This current gain is greater than 15A for rotational speeds above 2200 rpm.

In all the embodiments, the shutter 41 may further comprise damping elements 74 intended to bear against the facing face of the dissipator 32. These damping elements 74 are constituted for example for a raised wall with respect to the rest. of the body 48. The shutter 41 may also include notches 75 allowing the passage of the fastening columns 34 of the mezzanine, as shown in Figure 3a.

In addition, it will also be possible to provide guiding devices 76 for wires, particularly sensors, on the shutter 41. The shutter 41 which has just been described can generally be implemented in any type of shutter. alternator, comprising in particular a rotor with claws or salient poles.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention which would not be overcome by replacing the different elements by any other equivalent. For example, it will not depart from the scope of the invention by providing a rotating electrical machine whose bearing position and that of the assembly formed by the heat sink and the electronic power module are axially reversed, that is to say ie by proposing a machine in which the electronic assembly is integrated in the bearing.

In addition, the various features, variations, and / or embodiments of the present invention may be associated with each other in various combinations, to the extent that they are not incompatible or exclusive of each other.

Claims (14)

1. 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, 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 petal assembly (50) having at least one petal (51) foldable relative to the body (48), said at least one petal assembly ( 50) defining an opening (52) for the passage of a phase output (26). Rotary 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. rotary electric machine according to any one of claims 1 to 3, characterized in that the petal (51) is foldable in a groove (56) between the body (48) and the petal (51) corresponding. 5. Rotating electrical 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). Rotary electric machine according to any one of claims 1 to 4, characterized in that a petal (51) has a first position in an unconstrained state, that is to say in which no phase output ( 26) passes through the opening (52), and a second position in a constrained state, i.e. in which a phase output (26) passes through the opening (52). 7. Rotating electrical machine according to claim 6, characterized in that in the unconstrained state the petal (51) is located in a plane (P) in which extends the body (48) of the shutter (41). ). 8. Rotating electric machine according to claim 6, characterized in that in the unconstrained state the petal (51) is inclined relative to a plane (P) in which extends the body (48) of the shutter (41). 9. rotary 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. Rotating electric machine according to any one of claims 1 to 10, characterized in that the opening (52) defined by the petal assembly (50) has a diameter (L1) greater than or equal to the diameter of the outlet. corresponding phase (26). 12. A rotary electric machine according to any one of claims 1 to 11, characterized in that the shutter (41) comprises a stiffening rib (64) located on the body (48) around the petal (51). 13. Rotating 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 outlet (26) and the bearing (21). . 14. A 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) between two openings (52). consecutive phase output passages (26).