CN110192333B

CN110192333B - Rotary electric machine with baffle plate for limiting hot air loop

Info

Publication number: CN110192333B
Application number: CN201880007285.8A
Authority: CN
Inventors: M.法克斯; Y.勒-梅图尔; D.穆伊拉德; P-H.吉伯特; C.马赛; K.埃尔巴拉卡; S.朱戈维克
Original assignee: Valeo Equipements Electriques Moteur SAS
Current assignee: Valeo Equipements Electriques Moteur SAS
Priority date: 2017-01-27
Filing date: 2018-01-26
Publication date: 2021-09-28
Anticipated expiration: 2038-01-26
Also published as: WO2018138448A1; FR3062531A1; EP3574571A1; FR3062531B1; CN110192333A

Abstract

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

Description

Rotary electric machine with baffle plate for limiting hot air loop

Technical Field

The present invention relates to a rotary electric machine provided with a baffle plate that restricts the circulation of hot air. The invention has particular, but not exclusive, application with a rotating electrical machine operating at least in alternator mode.

Background

In a known manner, a rotary electric machine comprises a stator and a rotor integral with a shaft. The stator and rotor are mounted in a housing configured to rotate the shaft on bearings through roller bearings. The rotor may be a rotor having a claw including two magnet wheels and a core around which an excitation coil is wound. In another example, the rotor comprises a body formed by a stack of metal sheets, which are held in a pack by means of a suitable fixing system. The rotor comprises poles, for example formed by permanent magnets housed in cavities provided in the magnetic blocks of the rotor. Alternatively, in a so-called "salient" pole structure, the poles are formed by coils wound on rotor arms.

Furthermore, the stator comprises a body made of a stack of thin metal plates forming a crown, the inner surface of which is provided with notches open towards the inside in order to receive the phase windings. The windings pass through notches in the stator body and form chignons that protrude out of the two sides of the stator body. The phase windings are obtained, for example, from continuous wires covered with enamel, or from conductive elements in the form of pins, which are connected to each other by welding. These windings are polyphase windings which are connected in star or delta form, the outputs of which are connected to an electronic power module which in the case of an alternator comprises, in particular, a rectifier bridge. In the case of an alternator-starter, the rectifier bridge also operates in inverter mode.

As shown in fig. 1, to cool the electronic power module 1, the fan 2 fixed on the rotor 3 of the machine can generate a flow of air through the arrow F1 transversely into the interior of the channel defined by the face of the heat sink 4 (which faces the bearing 5) and the upper face of the bearing 5 (which faces the heat sink 4), then transversely back towards the outside of the machine according to the arrow F2.

However, the air at the output of fan 2 sweeps through winding bun 8, then phase output 6 of stator 7, and heats up. The axial air intake 11 through the bearing, according to the arrow F3, takes part of this air again into the machine, instead of discharging it to the outside. Therefore, the air temperature near the fins 9 of the radiator 4 is high, which reduces the cooling capacity of the machine.

It is known to mount a baffle 10 between the heat sink 4 and the bearing 5 in order to reduce the loop back of hot air at the air inlet 11 to pass through the phase outlet 6. The baffle 10 may protrude slightly above the air inlet 11 while allowing passage through the phase outlet 6. In this type of configuration, the air intake 11 for the passing phase is closed by about 40%, but this cannot prevent the hot air loop-back phenomenon.

Disclosure of Invention

The object of the present invention is to effectively eliminate this drawback by proposing a rotary electric machine comprising:

-a bearing;

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

-a heat sink associated with the electronic power module, to which the phase output is electrically connected; and

-a baffle mounted between the bearing and the heat sink,

characterized in that the baffle comprises a main body and at least one petal assembly comprising at least one petal bendable relative to the main body, the at least one petal assembly defining an opening for passage of the phase output.

The invention thus makes it possible to block substantially all of the air ingress of the bearing, due to the configuration of the flexible petals of the baffle. Thus, the air flow entering through the air with phase output is practically non-existent. This therefore isolates the air input path relative to the cooling air output path, which prevents the occurrence of a loop-back phenomenon of the hot air toward the inside of the motor. In addition, having flexible petals provides the petals with some flexibility, which makes it possible to ensure easy insertion of the phase output through the baffle.

According to an embodiment, the petal assembly includes at least two petals.

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

According to one embodiment, the petals are formed of an elastic material.

According to an embodiment, the petals are bendable along a groove located between the body and the respective petal.

According to an embodiment, the petals are integral with the body of the baffle.

According to an embodiment, the petals are overmoulded on the body of the baffle.

According to an embodiment, the thickness of the petals is less than the thickness of the body.

According to an embodiment, the petals have a first position in a non-stressed state, i.e. in which no phase output passes through the openings, and a second position in a stressed state, i.e. in which the phase output passes through the openings.

According to an embodiment, in the unstressed state, the petals lie on a plane on which the body of the baffle extends.

According to an embodiment, in the non-stressed state, the petals are inclined with respect to the plane on which the body of the shutter extends.

According to an embodiment, the petals are formed by a plurality of portions having different inclinations.

According to an embodiment, the petals comprise, at their free end sides, edges which, in the unstressed state, extend in a plane substantially parallel to the plane on which the body of the shutter extends.

According to an embodiment, the diameter of the opening defined by the petal assembly is greater than or equal to the diameter of the respective phase output.

According to an embodiment, the baffle comprises a reinforcing rib located on the body around the petal.

According to an embodiment, the baffle comprises at least one divider positioned radially between the phase output and the bearing.

According to an embodiment, the baffle comprises at least one curved portion matching the shape of the bearing, which portion is located between two passage openings of successive phase outputs.

The invention will be better understood upon reading the following description and examining the drawings that accompany it. These figures are provided purely for illustration and do not limit the invention in any way.

Drawings

Fig. 1, already described, shows a partial view in cross section of the rear part of a rotating electrical machine provided with a baffle according to the prior art;

fig. 2 shows a partial view in cross section of the rear part of a rotating electric machine provided with a baffle according to an example of the invention;

fig. 3a is a perspective view showing a first embodiment of a baffle according to the present invention mounted on a rear bearing of a rotary electric machine;

FIG. 3b is a detailed view of the petal assembly of the baffle of FIG. 3 a;

figure 3c shows a variant embodiment of the baffle according to the invention provided with reinforcing ribs;

FIG. 4 is a perspective view showing a second embodiment of a baffle according to the present invention;

FIGS. 5a and 5b are perspective and side views showing a third embodiment of a baffle according to the present invention;

FIG. 5c is a partial side view showing an example of a barrier divider of a baffle positioned between a phase output and a bearing according to the present invention;

FIG. 6 is a perspective view showing a fourth embodiment of a baffle according to the present invention;

fig. 7 shows a graphical representation of the development of the maximum acceptable current before triggering the thermal protection according to the speed of the rotating electric machine, respectively for the shutter according to the invention and the shutter according to the prior art;

fig. 8 is a partial view of a cross-section showing an example of the positioning of petals relative to the phase output.

In fig. 2 to 8, identical, similar or analogous elements retain the same reference numerals in the various figures.

Detailed Description

Fig. 2 shows a cross-sectional view of the rear part of the rotary electric machine 15, which rotary electric machine 15 can be reversibly operated in generator mode in order to supply the battery and the on-board network of the vehicle, and in motor mode in order to provide the thermal engine of the vehicle with mechanical power, in particular in order to ensure its starting.

The rotary electric machine 15 includes a rotor 16 mounted on a shaft 17 having an axis X and a stator 18 surrounding the rotor 16, with an air gap existing between the outer periphery of the rotor 16 and the inner periphery of the stator 18. The shaft 17 is fitted to rotate relative to a rear bearing 21 and comprises for this purpose a housing for a roller bearing 22. The stator 18, which is fitted to be fixed in the bearing 21, is provided with an armature winding comprising a chignon 25 which extends axially protruding relative to the stator body. Furthermore, the winding includes a phase output 26, the phase output 26 protruding axially with respect to the bun.

These phase outputs 26 are electrically connected to an electronic power module 29, the electrical connections not being shown in the figure. The electronic power module 29 comprises a rectifier bridge and an inverter, for example with power transistors of the MOS type. In the example described here, the electronic power module 29 is mounted on the upper face of the heat sink 32, where the upper face is the face axially opposite to the face of said heat sink facing the bearing 21. The electronic power module 29 is associated with an electronic control module 33. The electronic power module 29 and the heat sink 32 form a sandwich above the bearing 21. The interlayer is fixed to the bearing 21 by fixing posts 34 shown in figure 3 a.

A protective cover 35 surrounds the electronic power supply 29 and the control module 33 to protect them from the external environment.

In order to cool the electronic power module 29, a fan 38 fixed to the rotor 16 of the machine makes it possible to generate an air flow entering the casing of the rotating electrical machine through the arrow F1 and exiting from said casing through the arrow F2. In this embodiment, a passage for air entering the housing is defined between a lower face of the heat sink 32 facing the bearing 21 and an upper face 21 of said bearing facing said heat sink 32. In addition, air exits the housing which is driven laterally back underneath the bearing 21 and between the fan 38. The fins 39 obtained from the heat sink 32 may extend inside the passage for the air intake, preferably in the direction of the bearing 21.

Alternatively, a passage for air entering the housing may be defined between an upper face of the heat sink 32 (the face facing the cover 35) and a lower face of the cover 35 (the face facing said heat sink 32). Then, the fins 39 obtained from the heat sink may extend in the direction of the cover 35, and the power module 29 and/or the control module 33 may extend between the heat sink 32 and the bearing 21.

Further, the baffle 41 is installed between the bearing 21 and the heat sink 32. More specifically, in this case, the bearing 21 shown in fig. 3a comprises a transverse flange 42 provided with a central housing 43 for the roller bearing 22 and an air inlet 44 for the passage of air. The flange 42 extends at its outer periphery by an edge 45, the edge 45 having an axial orientation, provided with a transverse air inlet 47 for the passage of air and a phase output 26 designed to be connected to the electronic power module 29. The baffle 41 rests against the face of the flange 42 facing the heat sink 32. Preferably, the baffle 41, having axis Y, is coaxial with the bearing having axis X.

The baffle 41 makes it possible to isolate the air inlet flow F1 with respect to the air outlet flow F2, so that the air exiting from the rotating electric machine 15 is not immediately reintroduced into the machine. This therefore prevents a large recirculation of the hot air obtained from the inside of the machine.

To this end, the baffle 41 comprises a body 48 having an overall annular form and a petal assembly 50 which is bendable relative to the body 48. Each assembly 50 defines an opening 52 for passage of the phase output 26. In this case, the baffle 41 includes six petal assemblies 50 to allow the six-phase output 26 to pass through in the case of a dual three-phase type system. The six assemblies 50 are grouped into two series, each series of three assemblies angularly spaced from each other.

It will be appreciated that the number of petal assemblies 50 and their positioning along the stator circumference is dependent upon the configuration of the machine, and in particular upon its number of phases (in particular 3, 5, 6 or 7) and the positioning of the lugs for connection to the phase outputs 26 of the electronic power module 29.

More specifically, in the first embodiment, as can be seen in fig. 3b, each assembly 50 comprises four petals 51. The inner periphery of each petal 51 of the single assembly 50 defines an opening 52 for passage of the associated phase output. The diameter L1 of opening 52 is preferably greater than or equal to the diameter of the phase output 26.

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

To allow the petals 51 to be spaced apart during insertion of the output 26 into the respective openings 52, each petal 51 may be bent along a groove 56 located between the body 48 and the respective petal 51. In other words, each groove 56 forms a thin region between the petals 51 and the body 48, according to which the respective petals 51 can bend. Also preferably, the thickness L3 of the petals 51 is less than the thickness L2 of the body 48. The thickness is defined according to the axial direction.

According to one embodiment, the opening 52 defined by the petals 51 has a diameter L1 of about 4mm, the body 48 has a thickness L2 of about 1mm, and each petal 51 has a thickness L3 of about 0.5mm, while the thickness L4 of the groove region is about 0.3 mm.

In this case, the petals 51 are integral with the main body 48 of the shutter 41, i.e. they are made integral with the main body 48, for example during a moulding operation. For example, the body 48 and petals 51 are thus formed entirely of the same plastic material. The plastic material used may be more or less flexible, for example PA66 may be used.

As a variant, petals 51 may be overmoulded on body 48 of baffle 41. In this example, the body 48 is formed from a plastics material and the petals may be formed from a resilient material such as rubber.

In the example shown, two adjacent petals 51 extend according to two

edges

58, 59 of the body 48 that form a non-zero angle with respect to each other, so as to have a "V" form. The other two petals 51 extend according to

edges

60, 61, are substantially parallel to each other and are located on the extension of

edges

58 and 59, respectively. As a variant, the petals 51 can extend according to edges defining a square, rectangle, circle, semicircle or any other shape suitable for the application.

According to a variant embodiment shown in fig. 3c, the baffle plate 41 may comprise reinforcing ribs 64 located around the petals 51 and along the

edges

58, 59, 60, 61. The ribs 64 allow reinforcement of the baffle plate 41.

In the embodiment of fig. 4, the baffle 41 further comprises a curved portion 67 matching the shape of the bearing 21. There is a circumferential alternation between the curved portion 67 and successive petal assemblies 50. The wall 68 ensures the connection between the

parallel edges

60, 61 of the supporting petals 51 and the respective curved portions 67. The bent portion 67 makes it possible to facilitate the positioning of the shutter 41 by forming a guide for positioning said shutter on the bearing 21.

According to an embodiment, the petals may be in a first state (referred to as an unstressed state), i.e., when no phase output 26 passes through the opening 52, or in a second state (referred to as a stressed state), i.e., when the phase output 26 passes through the opening 52. As shown in fig. 8, once the phase output 26 is inserted into the opening 52, the latter can stress the petal 51 and place it in a second state, which is in a different position than in the unstressed state.

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

As a variant, in the embodiment illustrated in fig. 5a, 5b and 5c, in the non-stressed state, the petals 51 are inclined with respect to the plane P on which the body 48 of the shutter 41 extends, so as to have a pyramidal shape. For example, the petals may form an inclination angle A1 of about 45 with respect to the plane P over which the body 48 extends.

Each petal 51 may be formed of a plurality of parts. In the embodiment shown in fig. 5a, 5b and 5c, each petal 51 includes a sloped portion 69 and a rim 70. The inclined portion 69 extends between the body 48 and the rim 70 and the rim extends at the free end side of the flap 51. These edges 70 define the opening 52 for the passage of the phase output 26. Also in this example, in the non-stressed state, edge 70 extends in a plane substantially parallel to a plane P on which body 48 of baffle 41 extends. In a variant embodiment not shown, the petals can comprise a plurality of portions with different inclinations, so as to form a pyramidal shape.

This pyramidal shape may facilitate insertion of the phase output 26 through the opening 52 by creating a guide for the phase output.

In addition, the divider 71 extends axially projecting relative to the annular body 48 in a direction opposite to that of the petals 51. The divider 71 is designed to be positioned radially between the phase output 26 and the bearing 21, as shown in fig. 5 c. In this case, the divider 71 defines a circular arc shape along the circumference of the bearing 21. This separator 71 makes it possible to strengthen the electrical insulation between the bearing 21 (which is normally at ground potential) and the phase output 26. In particular, the separator 71 makes it possible to avoid the creation of a saline bridge.

According to a variant embodiment not shown, the spacers may also extend projecting axially with respect to the body 48 in the direction of the heat sink 32. This divider then makes it possible to improve the reduction of the recirculation of hot air in the casing of the rotary electric machine.

In the embodiment of fig. 6, each petal assembly 50 includes more than four petals. Thus, the number of petals can vary between a minimum of one petal and a maximum of about 10 petals. In addition, baffle 41 includes only three petal assemblies 50 to enable a three-phase system to be accommodated.

Fig. 7 shows the increase of the maximum current acceptable before the thermal protection triggering of the machine for blocking the whole of the portion of the air intake 47 allowing the passage of the phase output 26, of the shutter 41 according to the invention (see curve C1), in comparison with a shutter according to the prior art (see curve C2) blocking 40% of the portion of the air intake 47 allowing the passage of the corresponding phase output 26. For rotational speeds greater than 2200rpm, this current increase exceeds 15A.

In all embodiments, the baffle 41 may additionally comprise a damping element 74 designed to be supported on the face facing the radiator 32. These damping elements 74 are constituted, for example, by walls that are raised with respect to the rest of the body 48.

The baffle 41 may also include a cut-out 75 that allows the interlayer fixing post 34 to pass through, as shown in fig. 3 a.

A guide 76, in particular a sensor, for the conductor can also be provided on the flap 41.

The baffle 41 just described can be generally implemented in any type of alternator, including in particular a rotor with claws or with projecting poles.

It is to be understood that the foregoing description is provided purely by way of example, and is not intended to limit the scope of the invention, which does not constitute a departure from the scope, by replacing various elements with any other equivalent. For example, by proposing a rotating electrical machine whose position of the bearing and of the assembly formed by the heat sink and the electronic power module is axially reversed, i.e. by proposing a machine in which the electronic components are integrated in the bearing, does not constitute a departure from the context of the present invention.

In addition, different features, variations and/or embodiments of the invention may be related to each other according to various combinations, as long as they are not incompatible or mutually exclusive.

Claims

1. A rotating electrical machine (15) comprising:

-a bearing (21);

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

-a heat sink (32) associated with the electronic power module (29), the phase output (26) being electrically connected to the electronic power module (29); and

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

characterized in that said baffle (41) comprises a main body (48) and at least one petal assembly (50), said petal assembly (50) comprising at least one petal (51) bendable with respect to said main body (48), said at least one petal assembly (50) defining an opening (52) for the passage of the phase output (26).

2. A rotating electric machine according to claim 1, characterized in that the petal assembly (50) comprises at least two petals (51).

3. A rotating electric machine according to claim 1 or 2, characterized in that the petals (51) are formed of an elastic material.

4. A rotating electric machine according to claim 1 or 2, characterized in that the lobes (51) are bendable along a groove (56) located between the main body (48) and the respective lobe (51).

5. The rotating machine according to claim 1 or 2, characterized in that the thickness (L3) of the petals (51) is smaller than the thickness (L2) of the main body (48).

6. A rotating electric machine according to claim 1 or 2, characterized in that the petals (51) have a first position in a non-stressed state, in which no phase output (26) passes through the opening (52), and a second position in a stressed state, in which a phase output (26) passes through the opening (52).

7. A rotating electric machine according to claim 6, characterized in that, in a non-stressed state, the petals (51) are located on a plane (P) on which the body (48) of the shutter (41) extends.

8. Rotating electrical machine according to claim 6, characterized in that, in a non-stressed state, the petals (51) are inclined with respect to a plane (P) on which the body (48) of the shutter (41) extends.

9. A rotating electric machine according to claim 1 or 2, characterized in that the petals are formed by a plurality of portions having different inclinations.

10. A rotating electric machine according to claim 9, characterized in that the petals (51) comprise, at their free end sides, edges (70) which, in the unstressed state, extend on a plane substantially parallel to a plane (P) on which the body (48) of the shutter (41) extends.

11. A rotating electrical machine according to claim 1 or 2, wherein the diameter (L1) of the openings (52) defined by the petal assemblies (50) is greater than or equal to the diameter of the respective phase outputs (26).

12. A rotating electric machine according to claim 1 or 2, characterized in that the baffle (41) comprises reinforcing ribs (64) located on the body (48) around the petals (51).

13. A rotating electric machine according to claim 1 or 2, characterized in that the baffle (41) comprises at least one divider (71), the divider (71) being positioned radially between the phase output (26) and a bearing (21).

14. A rotating electric machine according to claim 1 or 2, characterized in that the baffle (41) comprises at least one curved portion (67) matching the shape of the bearing (21) between two openings (52) forming the passage of the continuous phase output (26).