EP3949091A1

EP3949091A1 - Retention system for an end wire of an electric rotor winding

Info

Publication number: EP3949091A1
Application number: EP20712394.4A
Authority: EP
Inventors: Olivier Thueur; Paul SAVARY; Olivier Christophe
Original assignee: Valeo Equipements Electriques Moteur SAS
Current assignee: Valeo Equipements Electriques Moteur SAS
Priority date: 2019-04-03
Filing date: 2020-03-25
Publication date: 2022-02-09
Also published as: FR3094850B1; WO2020200973A1; FR3094850A1; CN113692689A; JP2022526583A

Abstract

The invention relates to a retention system (11) for an end wire (15, 16) of an electric rotor winding, the system comprising a housing (50) for accommodating the wire, said housing extending between two side walls (52) connected together by a bottom wall (53) for the housing (50), and this housing (50) emerging outwards via an opening (54) provided between two retention walls (55), each retention wall (55) respectively projecting from a side wall (52) and, in a plane perpendicular to the longitudinal axis (X) of the housing (50), the retention walls (55) having a different shape from one another.

Description

Electric rotor winding end wire retention system

The present invention relates to an electrical rotor winding end wire retention system. Such a rotor is for example a claw rotor belonging to an electric machine forming an alternator or an alternator-starter or a vehicle propulsion motor supplied by a voltage of 12V or 48V. The electric rotor winding can then form the excitation coil of this rotor.

It is known to hold the rotor electrical winding end wires of such machines via holding systems, also called "clips". Each support system comprises a body within which is provided a housing receiving one of the end wires. The housing extends between two side walls connected to each other by a bottom wall for the housing, and this housing opens outwards through an opening formed between two retaining walls, each retaining wall respectively projecting from a side wall. . In a plane perpendicular to the longitudinal axis of the housing, the retaining walls have the same shape. Such a clip is for example known from application EP 3 028 373.

Maintaining end threads in such clips is not optimal, the thread being capable of coming out of the housing, for example at the end of the winding line, when assembling this end thread in a hook of the collector, or after transporting the coil thus produced. Consequently, an additional step of replacing the wire in the housing is necessary, which is costly in terms of time and resources.

There is a need to remedy the above drawback.

The object of the invention is to meet this need and it achieves this, according to one of its aspects, with the aid of a retaining system for an electric rotor winding end wire, the system comprising a housing for receiving the wire, this housing extending between two side walls interconnected by a bottom wall for the housing, and this housing opening outwards through an opening made between two retaining walls, each retaining wall s 'extending respectively projecting from a side wall and, in a plane perpendicular to the longitudinal axis of the housing, the retaining walls having a different shape from each other.

Due to the different shape of one retaining wall to another, the ability of the end wire to remain in the housing of the retaining system is increased. Thus, the manufacture of the rotor is simplified.

The housing may, in the plane perpendicular to its longitudinal axis, have an axis of symmetry and this axis of symmetry may not intersect the opening made between its retaining walls.

One of the retaining walls may project from a first side wall over a first length and the other of the retaining walls may project from a second side wall over a second length, less than the first. length. The longest leg thus promotes maintenance of the end wire in the housing by extending above the central zone of the housing, when observed in the plane perpendicular to its longitudinal axis.

The length of the retaining wall can be defined, in the plane perpendicular to the axis of the housing, as being the length measured along this retaining wall, whether the latter is rectilinear, or formed by a broken line or having a other form.

According to an exemplary implementation of the invention, each retaining wall may comprise a proximal part originating at the level of a side wall and a distal part, the free end of which defines an edge of the opening, the proximal part and the distal part not being aligned with one another, the distal part in particular approaching the bottom wall of the housing when one approaches its free end. The distal part can thus form an inwardly curved part, when viewed in the plane perpendicular to the longitudinal axis of the housing.

According to the implementation example above, the length of the proximal part may be different from one retaining wall to another. The difference in shape from one retaining wall to the other can thus only be due to a difference in length between proximal parts. In this case, the distal portions may have the same length from one retaining wall to the other.

Alternatively, the difference in the length of the proximal portions contributes to obtaining different shapes for the retaining walls without being the sole cause.

According to yet another variant of this exemplary implementation, the length of the proximal part may be the same from one support wall to another, but the length of the distal part of one of the support walls is greater. to that of the distal part of the other of the retaining walls.

When each retaining wall comprises a distal portion and a proximal portion not aligned with one another, each of these retaining walls, in the same plane perpendicular to the longitudinal axis of the housing, may have its proximal portion and its distal portion each extending rectilinearly so as to define an angle between them.

The angle can be constant from one retaining wall to the other, for example having a value between 10 ° and 60 °. Such an angle value can promote entry of the end wire into the housing from the outside. The above angle value corresponds to the state of no deformation when the end wire is introduced into the housing through the opening.

Alternatively, the angle value may differ from one retaining wall to another. The difference in shape between these two retaining walls can thus be caused, exclusively or partially, by this difference in angle value.

According to yet another variant of the implementation example described, one of the retaining walls does indeed have a proximal part and a distal part as mentioned above, these parts forming an angle between them, but the other retaining wall comprises only a single part which is rectilinear between its birth from the side wall and its free end defining an edge of the opening. This single part may or may not be directed towards the interior of the housing.

According to yet another variant of the exemplary implementation described, none of the holding walls has a proximal part and a distal part as mentioned above, each holding wall is formed only by a single part which is rectilinear between its origin from the side wall and its free end defining an edge of the opening. This single part may or may not be directed towards the interior of the accommodation.

In all of the foregoing, the support system may be in one piece, being made of plastic, for example of polymer, or being made of composite material.

In all of the above, the retainer system may be configured to receive within the housing a single rotor electric winding end wire.

Another subject of the invention, according to another of its aspects, is a set comprising:

- the system as defined above, and

- an electric rotor winding end wire, received in the opening of the system.

The system housing can accommodate a single end wire of an electric rotor winding.

The ratio in a plane perpendicular to the longitudinal axis of the opening between the size of the opening and the diameter of the wire can be between 0.5 and 1. The holding element can thus be used with wires of different diameters, thus having a "standard".

The ratio between the first length, that is to say the length of the longest retaining wall, and the diameter of the wire may be greater than 1, in particular be between 1.1 and 1.3, being by example equal to 1.2 with a tolerance of 1 mm for this length. These ratio values can make it possible to favor the positioning of the wire against the longest retaining wall.

The ratio between the thickness of the retaining wall having the first length and the diameter of the wire can be between 0.4 and 0.5, for example with a tolerance of 1 mm for this length.

Another subject of the invention, according to another of its aspects, is an electric machine rotor, comprising:

- a tree,

- a first and a second pole wheels fixed on the shaft,

- an electrical winding mounted via the interposition of a coil insulator around the shaft and disposed axially between the first and second pole wheels, and at least one retaining system as defined above, carried by the coil insulator and maintaining in the housing an end wire of the electrical winding, in particular only one end wire of this electrical winding.

The holding system is for example made in one piece with the coil insulation. As a variant, the holding system is attached, for example fixed or placed, on this coil insulator. When the retention system is not made in one piece with the coil insulation, this retention system can be rigidly fixed to this coil insulation.

The electrical winding forms, for example, the excitation winding of the rotor.

The rotor is advantageously a claw rotor, that is to say a rotor whose poles are in the form of claws. Each of the pole wheels, which are then arranged in an opposite and nested manner, then comprises claws. Each claw of a pole wheel extends towards the other pole wheel and is inserted between two consecutive claws of the opposite pole wheel. The claw rotor has magnetic parts, and the electric winding.

The rotor may include magnets, arranged between the magnetic poles formed by the claws, and serving to prevent the magnetic flux from passing directly from one pole to the other without passing through the stator.

The rotor can be associated with fans, mounted around the rotation shaft on either side of the pole wheels to cool the electrical winding.

The electrical winding of the rotor comprises two end wires which are for example connected to slip rings on which brushes rub to supply this electrical winding. Each end wire is for example bent at the top of the electrical winding and passes through a radial cavity, formed between a wall of a pole wheel and a recess of the fan, and an axial cavity, formed between the shaft and a recess of the fan.

The retaining system can be arranged in the radial cavity formed between the wall of the pole wheel and the recess of the fan or formed between the wall of the fan and a recess in the pole wheel.

A fold line within the retaining system may be provided, in order to modify, during the positioning of the retaining system in the rotor, the shape of this retaining system.

The invention may be better understood from reading the following description of an example of its implementation and from examining the appended drawing in which:

- Figure 1 shows an example of a rotor in which the holding systems according to the invention can be implemented,

- Figure 2 shows a holding system according to an example of implementation of the invention,

- Figure 3 shows a detail of the holding system of Figure 2, - Figure 4 illustrates the insertion of an end wire of the rotor excitation electric winding in the housing of the holding system of Figures 2 and 3,

- Figure 5 illustrates the retention in place in the housing of this end wire, once introduced, and

- Figure 6 schematically shows a variant of the holding system.

There is shown schematically in Figure 1 an electric machine 10 provided with a claw rotor 20 fixed to a drive shaft 21 of axis A. The shaft 21 is mounted to rotate freely relative to a stator ( not shown) by bearings 19.

The rotor 20 comprises in the example considered a coil insulator 17. This insulator is substantially cylindrical and is here mounted integral in rotation on a core 27 mounted on the central section of the shaft 21, and it is clamped axially between two wheels. poles 25, 26. In the example under consideration, this coil insulator plays the role of supporting the electrical excitation winding of the claw rotor. It isolates this electrical winding.

In known manner, each of the pole wheels 25, 26 comprises a series of claws 12, 13 which are for example twelve in number for each of the pole wheels 25, 26 and which are distributed angularly in a regular manner around the common axis A to the pole wheels 25, 26 and to the shaft 21.

Each of the claws 12, 13 of a pole wheel 26, 25 extends axially towards the other pole wheel 25, 26 facing each other, so that the claws 12, 13 are nested in one another.

Still in the example described, two fans 31, 32 are mounted integral around the shaft 21 and attached to the pole wheels 25, 26 to facilitate the circulation of air in the electric machine comprising the rotor.

The electrical winding 17 is produced using turns of an electrically conductive wire, such as a copper wire, so as to form layers of conductive wire superimposed radially. The conductive wire is coated with at least one layer of electrically insulating material. The electrical winding 17 comprises two end wires 15, 16 connected to a collector provided with two slip rings 28, 29 on which brushes rub to supply this electrical winding 17. The connection between the end wires 15 and 16 and slip rings 28, 29 respectively is produced as can be seen in Figure 1 by conductive blades which are arranged in recesses of the shaft 21. Each end wire 15, 16 is bent at the top of the coil 17 and passes through a radial cavity 35, 36, formed between the first pole wheel 25 and the fan 31, then is connected to said conductive blades. Passages 37 and 38 are arranged between the shaft 21 and the fan 31. The passages 37, 38 are made by recesses 41, 42 of the fan 31. In the example of FIG. 1, the radial cavities 35, 36 are produced by recesses 39, 40 of the fan 31, each recess 39, 40 forming a radial tunnel. In variants not shown, the radial cavities 35, 36 can be produced by recesses in the first pole wheel 25.

In the example of Figure 1, two retaining systems 11 of end wires 15, 16 are provided, these retaining systems 11 being described below. Each retaining system 11 makes it possible to maintain a respective end wire 15, 16 in the radial cavity 35, 36 between the first pole wheel 25 and the fan 31. Each retaining system 11 is integral with the coil insulator, being for example attached to this insulation or produced in one piece with the latter.

Each retaining system 11 can include a fold line so as to be folded over the first pole wheel 25 when mounting the claw rotor 20.

As can still be seen in Figure 1, the fan 31, which is the one facing the slip rings 28, 29 comprises two radial recesses 39, 40 intended to form the radial cavities 35, 36 between the wall 48 of the first wheel pole 25 and fan 31. In the example considered, each radial recess 39, 40 has an ogive shape and a depth adapted to the holding system 11. The fan 31 also comprises two axial recesses 41, 42 of semi-circular shape, the radius here is greater than the radius of the end wire 15, 16. Each axial recess 41, 42 is intended to form the axial cavities 37, 38 for the passage of an end wire 15, 16.

An example of implementation of the holding system 11 will now be described with reference to FIGS. 2 to 5.

As can be seen in Figure 2, the holding system 11 defines a housing 50 for receiving one of the end wires 15, 16. This housing 50 extends between two side walls 52 which are interconnected by a wall. bottom 53 for the housing 50. The holding system 11 is here in one piece and it can be made of polymer or composite material.

It is also noted that this housing opens outwardly through an opening 54 formed between two retaining walls 55, each retaining wall 55 respectively projecting from a side wall 52.

The retaining system 11 still bears low walls visible in FIG. 2 and arranged in a manner aligned with the side walls 52.

According to the invention, and as can be seen in FIG. 3, in a section plane perpendicular to the longitudinal axis X of the housing 50, the retaining walls 55 have a shape different from each other. It can be seen in particular in FIG. 3 that the housing 50 has an axis of symmetry Z in the aforementioned section plane and that this axis of symmetry does not intersect the opening 54 in the example described.

In the example considered, each retaining wall 55 defines in the aforementioned plane a broken line, being formed by a proximal part 60 originating on the corresponding side wall 52 and by a distal part 61 which extends the proximal part 60 in the direction of inside the housing 50 and which has a free end. It can be seen that for each retaining wall 55, the proximal part 60 and the distal part 61 are rectilinear and define between them an angle α. In the example under consideration, this angle a is constant from one retaining wall 55 to the other and has a value of between 10 ° and 60 °.

It can be seen in Figures 2 and 3 that one of the retaining walls 55 has a length, equal to the sum of the length measured along its distal part 61 and the length measured along its proximal part 60, which is greater than the corresponding length of the other retaining wall 55, thus conferring in the aforementioned plane a different shape between the retaining walls 55. This difference in shape is here caused by the greater length of one of the proximal parts 60 while the distal portions 61 have the same length.

In variants not shown, the difference in shape between the retaining walls 55 could result:

- a difference in length between the distal parts 61 and a difference in length between the proximal parts 60,

- a difference in length between the distal parts 61, the proximal parts 60 having the same length,

- a difference in angle formed between distal part 61 and proximal part 60 from one retaining wall 55 to the other, the distal portions 61 having the same length from one retaining wall 55 to the other and the proximal parts 60 having the same length from one retaining wall to the other,

- The realization in fully rectilinear form of one of the retaining walls 55 while the other retaining wall 55 has a proximal portion 60 and a distal portion 61 as mentioned above.

We can choose, in the above plan, for the ratio between the size of the opening 54 and the diameter of the end wire 15, 16 a value between 0.5 and 1.

It is also possible to choose for the ratio between the length of the longest retaining wall 55 and the diameter of the end wire a value of the order of 1.2, with a tolerance of 1 mm for this length. It is also possible to choose for the ratio between the thickness of the retaining wall 55 of greatest length and the diameter of the end wire a value between 0.4 and 0.5, with a tolerance of 1 mm for this length. .

The invention is not limited to what has just been described.

FIG. 6 represents, similarly to FIG. 2, a variant in which none of the retaining walls 55 has a proximal part and a distal part as mentioned above. In this variant, each retaining wall 55 is formed only by a single part which is rectilinear between its origin from the side wall 52 and its free end defining an edge of the opening 54. This single part may or may not be directed. towards the inside of the housing 50, for example making an angle of between 10 ° and 60 ° towards the inside of the housing 50, to promote entry of the end wire 15, 16 into the housing 50 and make it more difficult to output of the wire from this housing.

Claims

he. Retaining system (11) for an electric rotor winding end wire (15, 16), the system comprising a housing (50) for receiving the wire, this housing extending between two side walls (52) connected between they by a bottom wall (53) for the housing (50) *, and this housing (50) opening outwards through an opening (54) formed between two retaining walls (55), each retaining wall (55) ) extending respectively projecting from a side wall (52) and, in a plane perpendicular to the longitudinal axis (X) of the housing (50), the retaining walls (55) having a different shape from one of the 'other.

2. Retaining system according to claim 1, one of the retaining walls (55) projecting from a first side wall (52) over a first length and the other of the retaining walls (55) s'. extending projecting from a second side wall (52) a second length, less than the first length.

3. System according to one of the preceding claims, each retaining wall (55) comprising a proximal portion (60) originating at a side wall (52), and a distal portion (61) whose free end defines an edge of the opening (54), the proximal portion (60) and the distal portion (61) not being aligned with each other, the distal portion (61) approaching the bottom wall (53) of the housing when approaching its free end.

4. System according to the preceding claim, the length of the proximal part (60) being different from one retaining wall (55) to the other.

5. System according to claim 3 or 4, for each retaining wall (55) and in the same plane perpendicular to the longitudinal axis (X) of the housing (50), the proximal part (60) and the distal part (61 ) extending rectilinearly so as to define an angle (a) between them.

6. System according to claim 5, the angle (a) being constant from one retaining wall (55) to the other and having a value between 10 ° and 60 °.

7. System according to any one of the preceding claims, being in one piece, being in particular made of polymer or composite material.

8. Set including:

- the system (11) according to any one of the preceding claims, and

- an electric rotor winding end wire (15, 16) received in the opening (54) of the system.

9. The assembly of claim 8, the ratio in a plane perpendicular to the longitudinal axis (X) of the opening (54) between the size of the opening (54) and the diameter of the end wire (15, 16) being between 0.5 and 1, and or,

the system being according to claim 2, the ratio between the first length and the diameter of the end wire (15, 16) being greater than 1, being in particular between 1.1 and 1.3, and / or

the system being according to claim 2, the ratio between the thickness of the retaining wall

(55) having the first length and the diameter of the wire being between 0.4 and 0.5.

10. Electric machine rotor, comprising:

- a tree,

- a first and a second pole wheels fixed on the shaft,

- an electrical winding mounted via the interposition of a coil insulator around the shaft and disposed axially between the first and second pole wheels, and

- at least one holding system (11) according to any one of claims 1 to 8 carried by the coil insulator and holding in the housing (50) an end wire of the electric winding (15, 16) .

11. A rotor according to claim 10, a single end wire of the electrical winding (15,

16) being maintained in the housing (50).]