LIQUID COOLING MACHINE

Abstract

The invention relates to a rotary electric machine with liquid cooling, comprising a rotor with permanent magnets and a wound stator, the rotor comprising: (i) at least one rotor sheet stack, (ii) magnets housed in the sheet stack, and (iii) front and rear flanges adjacent to the sheet stack, the machine being configured to enable a cross-flow of the cooling liquid within the rotor sheet stack.

Claims

1-16. (canceled)

17. A rotary electric machine with liquid cooling, comprising a rotor with magnets and a wound stator, the rotor comprising: (i) at least one rotor sheet stack, (ii) magnets housed in said sheet stack, (iii) front and rear plates adjacent to said sheet stack, the machine being configured to enable a cross-flow of the cooling liquid within the rotor sheet stack; the machine comprising a supply of cooling liquid to the front and rear plates, the liquid supplying the front plate circulating from the front plate through the sheet stack via at least one cooling channel toward the rear plate before leaving the rotor via at least one discharge channel (33) delimited at least partially by the rear plate, and the liquid supplying the rear plate circulating from the rear plate toward the front plate via at least one cooling channel before leaving the rotor via at least one discharge channel delimited at least partially by the front plate, the front and rear plates each coming to bear axially against said rotor sheet stack at one end, and the discharge channels being formed hollow on the face of the plate turned toward said rotor sheet stack.

18. A rotary electric machine with liquid cooling, comprising a rotor with magnets and a wound stator, the rotor comprising: (i) at least one rotor sheet stack, (ii) magnets housed in said sheet stack, (iii) front and rear plates adjacent to said sheet stack, the machine being configured to enable a cross-flow of the cooling liquid within the rotor sheet stack, the machine comprising a supply of cooling liquid to the front and rear plates, the liquid supplying the front plate circulating from the front plate through the sheet stack via at least one cooling channel toward the rear plate before leaving the rotor via at least one discharge channel delimited at least partially by the rear plate, and the liquid supplying the rear plate circulating from the rear plate toward the front plate via at least one cooling channel before leaving the rotor via at least one discharge channel delimited at least partially by the front plate, the plates being supplied by a shaft of the rotor, the shaft comprising a central channel, this central channel communicating with the front plate by radial channels and with the rear plate by other radial channels.

19. A rotary electric machine with liquid cooling, comprising a rotor with magnets and a wound stator, the rotor comprising: (i) at least one rotor sheet stack, (ii) magnets housed in said sheet stack, (iii) front and rear plates adjacent to said stack of sheets, the machine being configured to enable a cross-flow of the cooling liquid within the rotor sheet stack the machine comprising a supply of cooling liquid to the front and rear plates, the liquid supplying the front plate circulating from the front plate through the sheet stack via at least one cooling channel toward the rear plate before leaving the rotor via at least one discharge channel delimited at least partially by the rear plate, and the liquid supplying the rear plate circulating from the rear plate toward the front plate via at least one cooling channel before leaving the rotor via at least one discharge channel delimited at least partially by the front plate, the plates being supplied with cooling liquid via an axial distribution channel of the cooling liquid formed in the rotor mass along the shaft.

20. The machine according claim 17, each plate comprising at least one supply channel through which the liquid supplying the plate reaches at least one cooling channel.

21. The machine according to claim 20, the supply channel being formed hollow on the face of the plate facing the rotor sheet stack.

22. The machine according to claim 20, the supply channels each have a Y or T shape.

23. The machine according claim 17, the front and rear plates being identical and angularly offset so as to supply different cooling channels,

24. The machine according to claim 23, the cooling channels traversed by the liquid flowing from the front plate to the rear plate being made within odd poles, and/or those traversed by the liquid in the opposite direction being located within even poles.

25. The machine according to claim 17, the sheet stack defining housings which receive magnet(s); the cooling channels being formed by space left free by the magnet(s) in these housings.

26. The machine according to claim 17, the discharge channels being formed by recesses whose depth increases on approaching the outer periphery of the plate.

27. The machine according to claim 17, the supply and discharge channels alternating in the circumferential direction on each plate.

28. The machine according to claim 17, each discharge channel having a substantially trapezoidal shape.

29. The machine according to claim 17, the supply of the plates being done by a shaft of the rotor.

30. The machine according to claim 17, the discharge channels emerging opposite the coil heads of the stator.

31. The machine according to claim 17, each plate being a casting.

32. A method for cooling a rotary electric machine as defined in claim 17, wherein the liquid is circulated in opposite directions within the rotor to cool the magnets, then the liquid is projected onto the coil heads of the stator after passing through the rotor sheet stack.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The invention will be better understood upon reading the following description of a non-limiting embodiment thereof, and on examining the appended drawings, in which:

[0034] FIG. 1 partially and schematically shows, in longitudinal section, a rotary electrical machine,

[0035] FIG. 2 shows the rotor of the machine of FIG. 1 in isolation, and illustrates the circulation of the cooling fluid in opposite directions within the rotor sheet stack,

[0036] FIG. 3 partially and schematically shows the rotor, showing a plate in cross-section in its thickness,

[0037] FIG. 4 shows a detail of the rotor sheet stack,

[0038] FIG. 5 shows a plate in isolation, and

[0039] FIG. 6 illustrates the cooling of the coil heads by the liquid projected by the discharge channels of the plates thereon.

DETAILED DESCRIPTION

[0040] The electric machine 1 according, partially shown in FIG. 1, comprises a rotor 10 rotating inside a stator 20 about an axis of rotation X.

[0041] The stator 20 comprises a stack 21 of stator sheets providing notches for electrical conductors of a winding. These conductors protrude axially from the sheet stack 21 to form coil heads 22, also called lead-out wires.

[0042] The rotor 10 comprises at least one rotor sheet stack 11 carried by a shaft 40 that is guided by bearings (not shown). This shaft 40 carries a pinion 48 at the front, which meshes with driven elements, not shown. The end of the shaft 40 carrying the pinion 48 is also called “drive end.”

[0043] As shown in FIG. 4, the stack 11 comprises housings 13 in which permanent magnets 14 are arranged, the magnetization of which can be carried out if necessary after they are installed in the housings 13.

[0044] The rotor 10 comprises two front and rear end plates 30a and 30b arranged against the corresponding ends of the stack 11.

[0045] The two plates 30a and 30b are identical in the example considered, and as illustrated in FIG. 5, on their face 31 facing the stack 11, have a set of recessed reliefs defining circulation passages for a cooling fluid.

[0046] This cooling fluid, which is preferably an oil, is brought through a central channel 41 of the shaft 40, as illustrated in FIG. 2.

[0047] This channel 41 communicates with the front plate 30a by radial channels 42 and with the rear plate 30b by other radial channels 43, of which in FIG. 2 we see only the mouth opening into the central channel 41, these channels 43 being angularly offset from the channels 42.

[0048] In reference to FIG. 5, one sees that each plate 30a or 30b comprises supply channels 32 in the general shape of a Y and discharge channels 33 that alternate with the supply channels [[33]] 32 and lead to the outer periphery of the plate.

[0049] As shown in FIG. 3, the supply channels 32 each have a radial branch 32a that is aligned with a radial channel 42 of the shaft 40 and opens onto the latter, and two oblique branches 32b in which the flow of liquid circulating in the branch 32a is distributed.

[0050] The branches 32b overlap at least partially with recesses 16 made in the sheets of the stack 11, and forming longitudinal cooling channels 17 through the stack 11, as illustrated in FIGS. 1 and 6.

[0051] The recesses 16 are made by cutting the sheets with the housings 13 of the magnets 14, and serve on the magnetic plane to channel the magnetic flux in the sheets of the stack 11. The discharge channels 33 are superimposed on the recesses 16 of the poles located between those that are supplied by the supply channels 32.

[0052] In the example considered, the rotor has 8 poles, and each plate 30a or 30b has four supply channels 32 and four discharge channels 33.

[0053] The plates 30a and 30b are angularly offset by 45° in the example considered.

[0054] Thus, the channels 17 formed within the stack 11 by the recesses 16 of the odd poles are superimposed at one end on the supply channels 32 of the front plate 30a and on the discharge channels 33 of the rear plate 30b, and the channels 17 formed by the recesses of the even poles overlap at one end with the discharge channels 33 of the front plate 30a and at the opposite end with the supply channels 32 of the rear plate 30b.

[0055] This allows circulations of the cooling liquid in opposite directions to be created within the rotor.

[0056] More precisely, as illustrated in FIGS. 2 and 3, the liquid arriving via the central channel 41 can reach the front plate 30a via the radial channels 42, then reach the channels 17 of the odd poles via the supply channels 32 and circulate from the front to the rear within the sheet stack (circle marked 1 in FIGS. 2 and 3), before reaching the discharge channels 33 of the rear plate 30b.

[0057] The liquid that does not pass through the channels 42 reaches the channels 43 by circulating along the central passage 41, then reaches the rear plate 30b and the supply channels 32 of the latter. The liquid then flows from the rear to the front in the channels 17 of the even poles (circle marked 2 in FIGS. 2 and 3), before reaching the discharge channels 33 of the front plate 30a.

[0058] Each discharge channel 33 has a substantially trapezoidal general shape, with opposite side edges 36 that diverge outwardly, as illustrated in FIG. 5.

[0059] The angular expanse occupied on the periphery of the plate by a discharge channel 33 is for example greater than or equal to 30° about the axis X.

[0060] The depth of the discharge channel 33, that is to say, the distance by which it is recessed with respect to the plane of the face 31 of the plate, can increase as illustrated in FIG. 6 with the distance to the center of the plate.

[0061] In FIG. 6, one can see that the bottom 37 of the discharge channel 33 has a planar shape inclined obliquely away from the stack 11.

[0062] The angular width of the outlet of the discharge channel 33, as well as the slope of its bottom 37, allow a large portion of the coil heads 22 to be sprinkled with the cooling liquid, as illustrated in FIG. 6.

[0063] The plates 30a and 30b are preferably made by casting, in aluminum or aluminum alloy, and can be held against the stack 11 by tie rods, not shown.

[0064] The faces 31 of the plates 30a and 30b advantageously come to cover the magnets 14 and thus contribute to their axial immobilization within the stack 31.

[0065] The operation of the machine is as follows.

[0066] During the rotation of the rotor 10, the cooling liquid circulates in the opposite direction within the sheet stack, as explained above, and cools the magnets. The liquid leaving the channels 17 provided within the stack 11 is sprayed by the discharge channels 33 on the coil heads 22 due to centrifugal force.

[0067] In view of the widened section of the outlets of the discharge channels 33, the formation of high-pressure fine jets is avoided, the impact of which on the coil heads would be likely to damage them.

[0068] In the example considered, the presence of the bend formed at the junction between the axial cooling channels 17 and the radial discharge channels 33 slows down the liquid and further reduces the impact speed on the coil heads.

[0069] The cooling fluid sprayed on the stator can be recovered and pumped outside the stator to be cooled before being reinjected through the hollow shaft 40.

[0070] Of course, the claimed invention is not limited to the example that has just been described.

[0071] The rotor may or may not be twisted.

[0072] The rotor can be made with other passages for the cooling fluid. The angular offset between the plates can be different from 45°, depending on the polarity of the machine.

[0073] In general, this offset can be 360°/n plus the possible twist angle of the rotor, where n designates the number of poles of the rotor. It can for example be 60° for a 6-pole machine.

[0074] Preferably, all the poles are cooled, but as a variant only some of them are, for example one pole out of two or one out of four.

[0075] The plates may have a shape other than that illustrated.