ROTARY ELECTRICAL MACHINE PROVIDED WITH A STATOR

Abstract

A stator of a rotary electrical machine has a stator body formed by a stack of metal sheets. The stator body is delimited by inner and outer radial surfaces. Notches in the stator body extend axially. Each notch has a notch base and a notch opening, and the notch opening is on the side of the inner radial surface. A stator winding is supported by the stator body, and the winding has a plurality of winding parts. Each part is accommodated in one of the notches. Each of the notches at the notch opening has a closure element. Each winding par in a notch is retained between the notch base and the closure element. The closure elements are formed by offsetting at least one of the metal sheets of an adjacent notch in the direction of the notch.

Claims

1. Stator (6) of a rotary electrical machine (1), comprising: a stator body (4) formed by a stack of metal sheets, said stator body being provided with an axis (X) and being delimited by an inner radial surface and an outer radial surface; notches (44) provided in said stator body and extending axially, each of them having a notch base (48) and a notch opening (49), said notch opening being situated on the side of said inner radial surface; a stator winding (5) supported by said stator body, said winding comprising a plurality of winding parts (51, 52, 53), each of them being accommodated in one of said notches, wherein each of the notches (44, 41, 42, 43) is provided at the notch opening with at least one notch closure element (451, 452, 453, 454), such that the winding part which is accommodated in said notch is retained between the notch base and said closure element, and wherein for each of the notches, said closure element is formed by offsetting (451, 452a, 452b, 453, 454) of at least one of the metal sheets of an adjacent notch in the direction of said notch.

2. Stator according to claim 1, wherein one notch out of two comprises a number N of closure elements, N being a whole number equal to 2 or more, and the remaining notches comprising a number of closure elements strictly smaller than N.

3. Stator according to claim 2, wherein two notches with a number N of closure elements are adjacent to both sides of a notch with a smaller number of closure elements.

4. Stator according to claim 1, wherein with the notches being numbered according to the circumference of the stator, the notches with an even number comprise a number of closure elements different from that of the notches with an odd number.

5. Stator according to claim 1, wherein the closure elements of the notches (42) are distributed axially along the axial length of the stator body.

6. Stator according to claim 5, wherein at least one of the closure elements of a notch (41, 43) with a smaller number of closure elements is situated on a radial plane which passes via the middle of two adjacent closure elements of a notch (42) comprising the N closure elements.

7. Stator according to claim 1, wherein, for a given notch (42), with the closure elements of this notch being situated respectively on first radial planes of the stator body, and the closure elements of the adjacent notch (41, 43) being situated respectively on second radial planes of the stator body, the first radial planes are different from the second radial planes.

8. Stator according to claim 7, wherein the first radial planes and the second radial planes are spaced axially by a distance equal to at least two metal sheets.

9. Stator according to claim 1, wherein a closure element (452) is formed firstly by the offsetting (452a) of at least one of the metal sheets of an adjacent notch to the right in the direction of said notch, and secondly by offsetting (452b) of at least one of the metal sheets of an adjacent notch to the left in the direction of said notch, the two offsettings being situated on the same radial plane.

10. Stator according to claim 1, wherein a closure element (451, 452, 453, 454) is formed by offsetting of at least two contiguous metal sheets, such that the closure element has an axial height of at least two metal sheets.

11. Stator according to claim 1, wherein, for each closure element of a notch (42), at least one of the two adjacent notches has traces of deformation by radial introduction of a tool (60) with an orthoradial dimension greater than the notch width.

12. Stator according to claim 1, wherein, for each closure element of a notch (42), at least one of the two adjacent notches has traces of deformation by radial introduction of a tool (60) with a substantially spherical form.

13. Stator according to claim 11, wherein the winding part (51, 52, 53) of a notch has traces of compacting by said radial introduction of the tool (60).

14. Stator according to claim 1, wherein the winding part (51, 52, 53) of a notch comprises a plurality of wires aligned according to a column.

15. Rotary electrical machine provided with a stator according to claim 1.

16. Stator according to claim 2, wherein with the notches being numbered according to the circumference of the stator, the notches with an even number comprise a number of closure elements different from that of the notches with an odd number.

17. Stator according to claim 3, wherein with the notches being numbered according to the circumference of the stator, the notches with an even number comprise a number of closure elements different from that of the notches with an odd number.

18. Stator according to claim 2, wherein the closure elements of the notches (42) are distributed axially along the axial length of the stator body.

19. Stator according to claim 3, wherein the closure elements of the notches (42) are distributed axially along the axial length of the stator body.

20. Stator according to claim 4, wherein the closure elements of the notches (42) are distributed axially along the axial length of the stator body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The invention will be better understood by reading the following description and examining the figures which accompany it. These figures are provided purely by way of illustration of the invention which is in no way limiting.

[0063] FIG. 1, already described, is a view of a rotary electrical machine;

[0064] FIG. 2 represents a view in perspective of a stator body of a rotary electrical machine in the form of an alternator;

[0065] FIG. 3 is a view of a detail of a stator body according to another embodiment of the invention;

[0066] FIG. 4 is a view in perspective of a stator according to the invention comprising a stator body and a winding;

[0067] FIGS. 5, 6, 7, 8 and 9 are views according to a radial cross-section of the stator according to FIG. 4;

[0068] FIG. 10 is an internal view of the stator according to the invention;

[0069] FIG. 11 is a schematic view of the steps of the method according to the invention.

[0070] Elements which are identical, similar or analogous retain the same reference from one figure to another.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0071] FIG. 2 illustrates a stator body 4 for a rotary electrical machine. The stator body is formed by a stack of metal sheets. It is provided with an axis X and is delimited by an inner radial surface and an outer radial surface. Notches 44 are provided in the stator body. These notches 44 extend axially, two notches 44 being separated by a tooth 45. Each of the notches 44 has a notch base 48 and a notch opening 49. The notch opening is situated on the inner radial surface side. For each notch, a radial notch depth is defined between the notch opening and the notch base.

[0072] FIG. 3 illustrates a stator body 4 for a rotary electrical machine according to another embodiment of the invention. This embodiment differs from the one in FIG. 2 by the presence of a tooth root 47 on each of the teeth 45. The tooth root 47 is formed by two projections with an orthoradial direction, one to the left 46a, and another to the right 46b.

[0073] FIG. 4 illustrates a stator body 4 supporting a winding 5. The stator body 4 and the winding form a stator 6 of a rotary electrical machine. In other words, the electrical machine stator 6 comprises a stator body 4 provided with notches 44 and a winding 5. The winding 5 comprises a plurality of winding parts 58, each of them being accommodated in one of the said notches 44. The winding comprises two chignons 56 and 57 situated axially on both sides of the stator body. The winding parts 58 connect the chignons 56 and 57. The winding additionally comprises inputs and outputs 55 which project axially relative to the chignon 57.

[0074] FIG. 5 illustrates a detail of the stator 6 in FIG. 4. More specifically, it is a cross-section according to a radial plane, which is used synonymously with being perpendicular to the axis X in the continuation of the description. This figure illustrates three notches 41, 42 and 43, which receive respectively the winding parts 51, 52 and 53. The notches 41, 42 and 43 are separated by the teeth 45. The teeth and the notches are covered with an insulating paper 50, also known as the insulator. This insulator is necessary in order to ensure electrical insulation between the winding parts 54 and the stator body 4. In fact, during the functioning of the electrical machine, a current passes through the winding parts, whereas the body is at the potential of the electrical earth. The thickness of the insulator is approximately a 10.sup.th of a millimetre. As can be seen in FIG. 5, the winding parts 51, 52 and 53 comprise for example 7 wires per notch aligned according to a radial column. The winding parts are not compacted, such that the last wire on the notch opening side extends from the inner radial surface of the stator body. For each notch, there is definition of a notch width 445 which corresponds to the distance according to an orthoradial direction between the two edges of the notch. For each notch, there is also definition of an insertion width corresponding to the orthoradial distance between the two edges of the notch when they are covered with the insulating paper 50. On the stator in FIG. 5, it can be seen that the wires are not retained at the level of the notch opening, and have a diameter smaller than the insertion width. There is therefore a risk that the last wire on the notch opening side will exit completely from the notch 54. For the embodiment in FIG. 5, the two starting notch edges for each notch of the notch base towards the notch opening are contained respectively on a straight line before the formation of the notch closure element. However, the invention also applies to the stator illustrated in FIG. 2, according to which each tooth is provided with tooth roots.

[0075] FIG. 6 illustrates the arrival of a tool 60 at the notch 41, the action of which tool eliminates the aforementioned risk. The tool is displaced by translation according to a radius aligned with the notch 41, and for example on a first radial plane perpendicular to the axis X. In other words, the tool is displaced radially relative to the notch into which it must be introduced. The tool illustrated in FIG. 6 has a spherical form, and has the advantage of not damaging the wire, and having a progressive orthoradial width which permits centring of the tool in the notch opening. However, any form of tool is appropriate, provided that it has a diameter greater than the notch width 445.

[0076] FIG. 7 illustrates the continuation of the displacement of the tool 60 in the direction of the notch opening of the notch 41. The continuation of this displacement involves compacting of the winding part 51 of the notch 41. Thus, the last wire no longer projects from the inner radial surface of the stator body. The continuation of the displacement also involves the formation of two closure elements 451 and 452a. The closure elements 451 and 452a are formed by the offsetting of some of the metal sheets of the notch 41 receiving the tool respectively to the left and to the right as illustrated in FIG. 7 by the two arrows. Thus, the closure elements 451 and 452a project in an orthoradial direction respectively within a notch which is not numbered and the notch 42.

[0077] In other words, at least one of the notches is provided at the notch opening with at least one notch closure element, such that the winding part which is accommodated in the said notch is retained between the notch base and the said closure element. The closure element is formed by offsetting of at least one of the metal sheets of an adjacent notch in the direction of the said notch.

[0078] It will be appreciated that there could also be N tools 60 distributed axially on the notch 41. This would then give rise to the formation of 2 N closure elements distributed axially. There would also be better compacting of the winding part 51 of the notch 41, thanks to the radial supports distributed axially. For this purpose, it is possible to provide a single tool with the said N tools 60, in order to facilitate their manipulation.

[0079] FIG. 8 illustrates the displacement of a tool 60 in the direction of the notch opening of the notch 42. According to a first embodiment, the tool 60 illustrated in FIG. 8 is the same as the one in FIG. 7. It is placed facing the notch 42 by means of a relative movement of rotation of the tool in relation to the stator. According to an example of this first embodiment, in order to go from the configuration in FIG. 7 to the one in FIG. 8, the tool 60 is retracted, the stator is turned, and the tool 60 is displaced in the direction of the notch 42. According to a second embodiment, the tool 60 is a tool in addition to the one illustrated in FIG. 7. It is different in that it is situated facing another notch, i.e. the notch 42, whereas the tool in FIG. 7 is facing the notch 41. According to an example of this second embodiment, the tool 60 in FIG. 7 is retracted, then the tool 60 in FIG. 8 is displaced in the direction of the notch 42.

[0080] According to the first or second embodiments, the offsetting is obtained of some of the metal sheets of the notch 42. The closure elements 453 and 454 are thus formed by this offsetting of the metal sheets of the notch 42 receiving the tool respectively to the left and to the right as illustrated in FIG. 8 by the two arrows. Thus, the closure elements 453 and 454 project in an orthoradial direction respectively within the notch 41 and the notch 43. According to these two embodiments, the displacement of the tool also involves compacting of the winding part 52 of the notch 42. Thus, the last wire no longer projects from the inner radial surface of the stator body.

[0081] In the case of the first embodiment, according to one embodiment the tool 60 retains the same axial position relative to the stator. This then provides closure elements 451, 452a, 453 and 454 which are situated on the same radial plane. According to another embodiment, it would be possible to carry out relative axial displacement of the tool 60 in relation to the stator 4. This relative axial displacement is carried out for example at the same time as the relative rotation of the stator 4 in relation to the tool 60. This then means that the closure elements 451, 452a are situated on a first radial plane, and the closure elements 453 and 454 are situated on a second radial plane, these first and second radial planes being different. For example, the first and second radial planes are situated at a distance greater than two metal sheets.

[0082] In the second embodiment, the tool 60 in FIG. 7 and the one in FIG. 8 can be situated on first and second substantially different radial planes. For example, the first radial plane and the second radial plane are spaced axially by a distance equal to at least two metal sheets. This then means that the closure elements 451, 452a are situated on the first radial plane, and the closure elements 453 and 454 are situated on the second radial plane, these first and second radial planes being different.

[0083] It will be appreciated that, as already stated for FIG. 7, N tools 60 could also be provided, distributed axially on the notch 42. They would then give rise to the formation of 2 N closure elements distributed axially. There would also be better compacting of the winding part 52 of the notch 42, thanks to the radial supports distributed axially. For this purpose, it is possible to provide a single tool of the said N tools 60, in order to facilitate their manipulation.

[0084] FIG. 9 illustrates the displacement of a tool 60 in the direction of the notch opening of the notch 43. As already stated, the tool 60 illustrated in FIG. 9 can be the same as the one in FIG. 8. It can also be different. It is also possible to provide a tool 60 which is not identical to the one facing the notch 42, but identical to the one facing the notch 41. This is then for example a notch closure method comprising two tools situated facing two consecutive notches during which, after a step of displacement towards the notch opening and a step of retraction of the two tools, the two tools are displaced in rotation by an angle corresponding to two notches relative to the stator.

[0085] The closure elements 452b and 455 formed by the tool 60 are in all cases on the plane of the tool 60 in FIG. 9.

[0086] It can be noted that the closure elements 453 and 452a on the one hand and 454 and 452b on the other hand are situated respectively on a single tooth 45. It thus appears that it can be advantageous for the closure elements 453 and 452a on the one hand to be on two different radial planes, and also for 454 and 452b to be on two different radial planes.

[0087] The fact of choosing to have the closure elements 453 and 452a on two different radial planes in fact makes it possible to prevent the formation of the closure element 453 by offsetting of the metal sheets to the left from interfering with the formation of the closure element 452a by offsetting of the metal sheets to the right.

[0088] Similarly, the fact of choosing to have the closure elements 454 and 452b on two different radial planes makes it possible to prevent the formation of the closure element 452b by offsetting of the metal sheets to the left from interfering with the formation of the closure element 454 by offsetting of the metal sheets to the right.

[0089] This phenomenon illustrated by way of example for the formation elements 453, 452a on the one hand, and 454 and 452b on the other hand is known as interference in the continuation of the description.

[0090] The dimensions of the tool 60 depend in particular on the size of the wire, the radial depth of the notch, the notch width, the insertion width, the width of the insulator and the number of wires per notch.

[0091] For example, with reference to FIGS. 7 and 9, there is a notch width of 1.95 mm, a wire size of approximately 1.56 mm, and an insulator with a thickness of 0.13 mm. This therefore provides an insertion width of 1.9520.13=1.69, whereas the wire has a size of 1.56 mm. In addition, the radial depth of the notch is approximately 12.5 mm. Taking into account the fact that the notch base is covered with insulator, this therefore provides a depth for the winding part equal to 12.50.13=12.37 mm. The objective is to obtain compacting which is sufficient for at least the set of 7 conductors to be able to enter into this length of 12.37 mm. According to one embodiment, it can be defined that the radial gap between two wires is a maximum of 0.1 mm. It can be deduced that it is then necessary to have penetration of the tool 60 by a value as calculated as follows in the notch: 12.37(71.56+60.1)=0.85 mm.

[0092] It is then necessary to define a tool form which, for this penetration value of 0.85 mm, permits offsetting of the metal sheets which is sufficient to allow wire to be retained in the adjacent notches. This necessary offsetting can be calculated according to the difference between the insertion width and the wire size. The value of the offsetting also depends on the presence of two offsettings facing one another in a single notch and on the same radial plane for the closure element. Specifically, the value of the offsetting must be greater if the closure element is formed solely by the offsetting to the right of the tooth between the notches 41 and 42, or by the offsetting to the left of the tooth between the notches 42 and 43. On the other hand, if the closure element is formed by the offsetting to the right of the tooth between the notches 41 and 42, and by the offsetting to the left of the tooth between the notches 42 and 43, then the value of each of the two offsettings can be less great.

[0093] Thus, in the case when the closure element 452 is formed solely by the offsetting 452a or 452b, then it is necessary to have offsetting which compensates at least for the difference between the insertion width and the wire size, i.e.: 1.691.56=0.13 mm.

[0094] In the case when the closure element is formed by the offsetting 452a and the offsetting 452b, then it is sufficient to have offsetting which is two times less great, if it is assumed for example that the offsetting 452a is equal to the offsetting 452b, i.e. (1.691.56)/2=0.065.

[0095] There is thus a tool form which must permit offsetting of at least 0.13 mm or 0.065 mm on each of the two teeth, relative to the insertion width of 1.56 mm, for an introduction of 0.85 mm. In the case of a tool with a spherical form, this is possible with a sphere with a diameter of 4 mm.

[0096] In addition, three embodiments listed below can be cited by way of example:

Embodiment 1

[0097] the tool for the notches 41, 42 and 43 is identical. According to an example of this embodiment, if only one relative rotation of the stator takes place in relation to the tool, there are then the closure elements 451, 452a, 453, 454, 455 and 452b which are situated on the same radial plane. There is then in particular a single closure element 452 formed by the two elements 452a and 452b.

Embodiment 2

[0098] the tools for the notches 42 and 43 are different. According to an example of this embodiment, there are then the closure elements 453 and 454 on the one hand, and 455 and 452b on the other hand, which are situated in sets of two, on two different radial planes.

Embodiment 3

[0099] the tool for the notches 41 and 43 is identical. According to an example of this embodiment, if there is only one relative rotation of the stator in relation to the tool, there are then the closure elements 451, 452a, 455 and 452b which are situated on the same radial plane, whereas the closure elements 453 and 454 are for example situated on another radial plane. This therefore prevents the aforementioned phenomenon of interference. Also, a single closure element 452 is obtained, formed by the two elements 452a and 452b.

[0100] As already stated for FIGS. 7 and 8, it will be appreciated that N tools 60 could also be provided, distributed axially on the notch 43, which would then give rise to the formation of a maximum of 2 N closure elements distributed axially. There would also be better compacting of the winding part 53 of the notch 43, thanks to the radial supports distributed axially.

[0101] FIG. 10 illustrates N=2 tools for the notches 41 and 43 and N=1 tool for the notch 42. More generally, according to FIG. 10, one out of two notches is deformed with one tool, and the remaining notches are deformed with two tools. There is also a notch deformed with one tool surrounded by two notches deformed with two tools.

[0102] In other words, one notch out of two comprises a number N of closure elements, N being a whole number equal to 2 or more, and the remaining notches comprise a smaller number of closure elements. For example, a number N of closure elements are adjacent to both sides of a notch with a number N1 of closure elements. According to one example, with the notches being numbered according to the circumference of the stator, the notches with an even number comprise a number of closure elements different from that of the notches with an odd number.

[0103] As can be seen for the notch 42, the closure elements 472 and 462 are distributed axially along the axial length of the stator body. In addition, as can be seen for the notch 41 or 43 comprising N1 closure elements, the closure element 461 or 463 is situated on a radial plane which passes via the middle of two adjacent closure elements of the notch 42.

[0104] It is found that for the notch 42 for example, the closure elements 462 and 472 of this notch are situated respectively on first radial planes of the stator body, and the closure elements 461 or 463 of the adjacent notch 41 or 43 are situated respectively on second radial planes of the stator body, the first radial planes being different from the second radial planes. For example, the first radial planes and the second radial planes are spaced axially by a distance equal to at least two metal sheets.

[0105] As can be seen for the notch 41 or 43, the closure element 461 or 463 is formed firstly by the offsetting of at least one of the metal sheets of an adjacent notch to the right in the direction of the said notch, and secondly offsetting of at least one of the metal sheets of an adjacent notch to the left in the direction of the said notch, the two offsettings being situated on the same radial plane. Similarly, for the notch 42, the two closure elements 472 and 462 are formed firstly by the offsetting of at least one of the metal sheets of an adjacent notch 43 to the right in the direction of the said notch, and secondly offsetting of at least one of the metal sheets of an adjacent notch 41 to the left in the direction of the said notch, the two offsettings being situated on the same radial plane.

[0106] For example, a closure element is formed by offsetting of at least two contiguous metal sheets, such that the closure element has an axial height of at least two metal sheets.

[0107] According to FIG. 10, for each closure element of a notch, at least one of the two adjacent notches has traces of deformation by radial introduction of a tool with an orthoradial dimension greater than the notch width. For example, for each closure element of the notch, at least one of the two adjacent notches has traces of deformation by radial introduction of a tool with a substantially spherical form.

[0108] According to one embodiment, the set of two tools of the notch 41 and the set of two tools of the notch 43 are identical. For this purpose, it is possible to provide a single tool for the set of two tools 60 which deforms the notches 41 and 43.

[0109] According to an example of this embodiment, it is possible to carry out only one relative rotation by an angle corresponding to two notches of the stator in relation to the tool, in order to go from the notch 41 to the notch 43. In particular, for the notch 42, there is then a closure element 472a or 462a obtained from the deformation of the notch 41 on the same radial plane as a closure element 472b or 462b obtained from the deformation of the notch 43. In other words, the first set of closure elements 472a and 472b, and the second set of closure elements 462a and 462b are each on a radial plane, and each of these two sets thus forms a single closure element 462 or 472.

[0110] According to an example of this embodiment, the closure elements 461 and 463 formed by the deformation of the notch 42 can be situated on radial planes other than those of the closure elements 462 and 472 of the notch 42. This therefore prevents the aforementioned phenomenon of interference.

[0111] According to one embodiment, the tool 60 which deforms the notches 40, 42 and 44 can be identical, and can act on the various aforementioned notches by rotation by an angle corresponding to two notches. In this case, the closure elements (in particular 461, 463) formed by the deformation of the notches 40, 42 and 440 can be situated on the same radial plane, which is different from the radial planes of the closure elements obtained from the deformation of the notch 41 or the notch 43. This therefore also prevents the aforementioned phenomenon of interference.

[0112] More generally, the cases described hereinafter by way of example do not depart from the context of the invention.

[0113] Case 1 (not illustrated in FIG. 10): the sets of N tools which act on the successive notches are the same set. According to an example of this embodiment, if there is only one relative rotation of the stator in relation to the tool, there is then a number of radial planes comprising at least one closure element equal to N, and each of the radial planes comprises the same number of closure elements.

[0114] Case 2: the set of tools acting on the notch 42 is different from the one which acts on the notch 43. According to an example of this second case, the closure elements 462 and 463 obtained from the deformation of the notch 42 are situated on planes different from those of the closure elements 472b and 462b obtained from the deformation of the notch 43. In other words, for a tooth with the reference 456 in FIG. 10, the offsettings of the metal sheets to the left 472b and 462b caused by the deformation of the notch 43, and the offsettings of the metal sheets to the right 472a and 462a caused by the deformation of the notch 42, will never be situated on the radial plane, and this therefore prevents the aforementioned phenomenon of interference.

[0115] Case 3: the sets of N tools acting on the notches 41 and 43 are the same set. According to an example of this case, if there is only one relative rotation of the stator in relation to the set of N tools, there is then in particular for the notch 42 for the closure elements 472a and 462a, obtained from the deformation of the notch 41, a closure element 467a or 462b, obtained from the deformation of the notch 43, which is on the same radial plane. The two closure elements on the same radial plane obtained respectively from the deformation of the notch 41 and the deformation of the notch 43 form a single closure element 462 or 472. According to one example, this case 3 can be combined with the case 2 of this embodiment, and this therefore prevents the aforementioned phenomenon of interference for the tooth 456 in particular.

[0116] FIG. 11 illustrates a method for production of a stator of a rotary electrical machine as illustrated above. The method comprises a closure step 111 which comprises a step of offsetting of at least one of the metal sheets of an adjacent notch in the direction of the said notch.

[0117] For example, the offsetting step is carried out on an axial height of at least two metal sheets. As has been illustrated above, the offsetting step comprises a step of introduction of a tool according to a radial direction, the said tool having an orthoradial dimension greater than the notch width.

[0118] In addition, the method also comprises a step 112 of compacting of the winding part accommodated in the notch into which the tool is introduced according to a radial direction. According to one embodiment, this compacting is carried out during the said offsetting step.