Rotor comprising pole shoes with cooling channels

Abstract

The present invention relates to a rotor for a rotary electric machine, extending along a longitudinal axis, including: projecting poles having pole shoes, and at least one internal cooling channel extending axially along at least one pole shoe.

Claims

1. Rotor for an electrical rotating machine, extending along a longitudinal axis, comprising: salient poles, each comprising a pole body which extends along a center line, and two pole shoes which protrude in the circumferential direction, and internal cooling channels running axially through at least one pole shoe, the cooling channels being separated within the pole shoe by fins, all the cooling channels being present only in the pole shoe(s).

2. Rotor according to claim 1, the pole shoes of the salient poles each having 2 to 15 cooling channels running through them.

3. Rotor according to claim 1, the cooling channels running through the whole length of the magnetic mass of the rotor.

4. Rotor according to claim 1, the cooling channels continuously running through the rotor along its longitudinal axis.

5. Rotor according to claim 1, the pole shoes each having a dentate shape defining teeth.

6. Rotor according to the claim 5, two consecutive series of teeth, when moving around the longitudinal axis of the rotor, being offset axially by one tooth.

7. Rotor according to claim 5, the axial dimension of one tooth being equal to that of the gap between two teeth.

8. Rotor according to claim 1, each pole shoe having a cut-out section representing more than 25% of its total section.

9. Rotor according to claim 1, two adjacent salient poles defining between them an interpolar space, at least one cooling channel running through an extension at the base of the interpolar space.

10. Rotor according to claim 1, the salient poles being formed by an assembly of identical and one-piece magnetic sheets.

11. Rotor according to claim 1, being in one piece.

12. Electrical rotating machine comprising a rotor according to claim 1.

13. Rotor for an electrical rotating machine, extending along a longitudinal axis, comprising: salient poles, each comprising a pole body which extends along a center line and two pole shoes which protrude in the circumferential direction, two adjacent salient poles defining between them an interpolar space, and internal cooling channels running axially through at least one pole shoe, the cooling channels being separated within the pole shoe by fins, several internal cooling channels being arranged side by side extending along face(s) of the pole shoe(s) adjacent to the interpolar space, their fins being perpendicular to said face adjacent to the interpolar space.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be better understood on reading the following description of non-limiting exemplary embodiments of the latter and on examining the appended drawing in which:

(2) FIG. 1 is a schematic and partial perspective of an example of magnetic carcass of a rotor according to the invention,

(3) FIG. 2 is a front view along II of FIG. 1,

(4) FIG. 3 is a view similar to FIG. 1 of another example of a magnetic carcass of a rotor according to the invention,

(5) FIG. 4 represents in isolation and partially a salient pole according to an exemplary embodiment of the invention, and

(6) FIG. 5 represents a detail of the production of an electrical machine according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(7) FIG. 1 shows a first example of magnetic mass of a rotor 1 which extends along a longitudinal axis X and comprises an assembly of magnetic sheets 2, forming salient poles 3, being four in number in the example illustrated, the invention not however being limited to a particular polarity.

(8) As can be seen in FIG. 1, each pole 3 comprises a pole body 3b, which extends along a centre line Y, and two pole shoes 3a which protrude in the circumferential direction.

(9) Two adjacent poles 3 define between them an interpolar space E.

(10) Electrical conductors are wound around each pole 3 and define windings 21 that can be seen in FIG. 5.

(11) Each sheet is preferably in one piece being cut out from one and same magnetic flat band.

(12) The rotor 1 may comprise tie-rods (not shown) for retaining the assembly of magnetic sheets 2 passing through the rotor mass by virtue of openings 11 situated on the poles 3.

(13) A central housing 8, furnished with an anti-rotation means 9, is arranged in the rotor mass in order to receive a shaft (not shown).

(14) The rotor mass of the rotor 1 may also comprise, as illustrated, housings 10 for receiving dampers (not shown).

(15) According to the invention, at least one internal cooling channel 5 runs axially through each pole shoe 3a. Within a sheet, this channel does not lead to the outer contour of the sheet, the contour of the channel being closed.

(16) Preferably, several cooling channels 5 run through each pole shoe 3a, for example six channels, as illustrated in FIGS. 1 and 2.

(17) Fins 4 made in the pole shoes 3a of the poles 3 separate the various cooling channels 5.

(18) In the example of FIGS. 1 and 2, each cooling channel 5 runs through the whole length L of the rotor 1 continuously without interruption.

(19) The magnetic mass may be formed by the stacking of identical magnetic sheets, the channels 5 and the fins 4 being formed by cutting out the sheet within the pole shoes.

(20) At the base of each interpolar space E, an additional cooling channel 7 may be provided as illustrated.

(21) The channel 7 is for example of circular section, being, for example made in an extension 18 in the form of a right angle, with sides parallel to the faces 19 opposite the pole shoes 3a.

(22) In the variant illustrated in FIG. 3, the pole shoes 3a each have a dentate shape defining teeth 6, numbering five per pole shoe 3a in the example described, the invention however not being limited to a particular number of teeth.

(23) The cooling channels 5 are arranged in the teeth 6, and the gap 20 between the teeth 6 defines a passageway of widened section for the cooling fluid.

(24) When moving around the longitudinal axis X of the rotor 1, two consecutive series of teeth 6 are offset axially by one tooth, the axial dimension L.sub.a along the axis X of a tooth 6 is able to be equal to the dimension L.sub.e of the gap 20 between two teeth 6.

(25) The pole shoes 3a of one and the same pole advantageously have no teeth at two opposite axial ends 14, 15, as shown in FIG. 3. This makes the installation of the windings easier, which can be carried out with prefabricated windings.

(26) Each pole shoe 3a has a total section s shown with cross hatching in FIG. 4, and a cut-out section s.sub.a, defined by the cooling channels 5 running through the pole shoe 3a. The cut-out section s.sub.a, preferably represents more than 25% of the total section s.sub.t of the pole shoe 3a. The section s.sub.t is delimited by the external contour of the shoe 3a and by an imagined straight line extending the body 3b of the pole.

(27) The channels 5 may have different sections within one and the same pole shoe 3a.

(28) In order to produce the magnetic mass of FIG. 3, identical sheets are used but inverted in packs so as to form the alternation of teeth 6 and of widened passageways 20 between two consecutive teeth 6.

(29) The rotor 1 is for example incorporated into an electrical rotating machine, not shown, comprising a centrifugal fan. As a variant, the fan is a multi-channel fan. In yet another variant, the fan is made by placing in series a centrifugal fan and an axial fan.

(30) The air aspirated by the fan passes through the cooling channels 5 situated in the pole shoes 3a of each salient pole 3. Moreover, the air can flow in the air gap and through the channels 7 arranged at the base of the interpolar spaces E.

(31) When the channels 5 run discontinuously through the pole shoes 3a, that is to say when the pole shoes of the salient poles 3 each have a dentate shape as illustrated in FIG. 3, such a discontinuity allows a transverse flow of the air from the gaps 20 between two teeth 6 to the interpolar space E.

(32) FIG. 5 shows partially the stator and the rotor of an electrical rotating machine according to the invention. This figure shows that the single cut-out of the extension 18 defining the channel 7 of the examples of FIGS. 1 and 3 can be replaced by a plurality of channels 7 separated by fins 23.

(33) The invention is not limited to the examples that have just been described.

(34) It is possible for example to combine the features described with reference to various embodiments within variants that are not illustrated.

(35) The fins 4 may be of any shape.

(36) The invention may be applied to rotors with fitted pole shoes. The invention is not limited to particular salient poles.

(37) The invention may apply to one-piece rotors machined in a solid piece of a magnetic material.

(38) The expression comprising one must be understood to be synonymous with comprising at least one, unless the contrary is specified.