CN115244828A

CN115244828A - Plastic flange with reinforced rim for a rotating electrical machine

Info

Publication number: CN115244828A
Application number: CN202180019820.3A
Authority: CN
Inventors: F.托伊伦; A-F.查尔斯; R.巴赫里; V.库普萨米; S.戈文达拉杰; I.穆尔迪
Original assignee: Valeo Equipements Electriques Moteur SAS
Current assignee: Valeo Equipements Electriques Moteur SAS
Priority date: 2020-03-09
Filing date: 2021-02-26
Publication date: 2022-10-25
Also published as: WO2021180489A1; FR3108000B1; FR3108000A1

Abstract

The invention proposes a plastic flange for a rotating electrical machine having an axis X, comprising a base (2) extending transversely to the axis X and a side wall (3) extending axially from the periphery of the base, characterized in that at least one of the base (2) and the side wall (3) has a surface from which at least one reinforcing rim (4) extends.

Description

Plastic flange with reinforced rim for a rotating electrical machine

Technical Field

The invention relates in particular to a rotating electric machine comprising a casing including at least one flange made of plastic material provided with a reinforcing rim.

The invention is particularly advantageously applied in the field of rotating electrical machines, such as alternators, alternator-starters, or reversible electrical machines or motors. It should be recalled that a reversible electric machine is a rotary electric machine that can be reversibly operated, on the one hand as a generator when used as an alternator, and on the other hand as an electric motor, for example in order to start a thermal engine of a motor vehicle.

Background

A rotary electric machine includes a rotor that is rotationally movable about an axis and a stationary stator that surrounds the rotor. In alternator mode, when the rotor rotates, it induces a magnetic field on the stator, which converts it into an electric current, thus powering the electric consumers of the vehicle and charging the accumulator. In the motor mode, the stator is powered by a power supply, induces a magnetic field, and drives the rotor to rotate through the bearing. The rotating electrical machine also comprises an electronic assembly comprising a plurality of power modules which make it possible to rectify the current supplied by the stator. The electronic module is mounted on the housing of the electric machine, in particular on a flange forming the housing. Furthermore, the housing makes it possible to hold and protect the assembly formed by the stator and the rotor.

To reduce the total weight of the machine, to limit the CO ₂ With the aim of emissions, in order to comply with anti-pollution standards, flanges made of plastic material have been developed.

The plastic flange is less rigid than the metal flange, in which the motor is housed, on which the electronic equipment is particularly mounted, subject to considerable mechanical stresses. In particular, when the motor is subjected to strong vibrations of the vehicle, the flange is significantly deformed.

Disclosure of Invention

The invention proposes a plastic flange for a rotary electric machine having an axis X, comprising a base extending transversely to the axis X and a side wall extending axially from the periphery of the base, characterized in that at least one of the base and the side wall has a surface from which a reinforcing rim extends.

The rim makes it possible to harden the flange, thereby reducing deformation. Furthermore, this type of flange, which is partially hollowed out by the cavity, is even further mitigated.

According to other features taken alone or in combination:

the plastic flange is obtained by moulding;

the flange includes a plurality of rims defining an enclosed cavity;

the cavities are substantially identical to each other;

the cross-section of the cavity in a plane transverse to the axis X has at least two axes of symmetry;

the cavity has a hexagonal cross-section;

the thickness of at least one rim is between one quarter and one times the thickness of the base or the side wall extending therefrom, and preferably about half the thickness of the base or the side wall extending therefrom;

the axial height of at least one rim is between half and three times the thickness of the base or the side wall extending therefrom, and is preferably about the thickness of the base or the side wall extending therefrom;

the surface is an outer surface, the flange further comprising an inner surface from which also extends a further plurality of edges, at least one edge of the outer surface being axially aligned with at least one edge of the inner surface;

the flange further includes a central opening for passage of the shaft and a hub extending from the central opening, and wherein the cavity is formed on a base of the flange: first by one or more from two more of: a plurality of peripheral radial rims extending radially from the sidewall relative to an axis of the electric machine; and a plurality of central radial rims extending radially from the rim with respect to the axis of the machine; second a circumferential rim extending transversely to the plurality of radial rims about the axis of the motor;

the flange comprises a plurality of central radial rims and a plurality of peripheral radial rims, the ratio between the number of peripheral radial rims and the number of central radial rims being between 1 and 2, preferably equal to 1.5;

two angularly adjacent edges of one of the plurality of edges are angularly separated by an angle generally between 10 ° and 15 °, the angle being measured from the axis X on a plane perpendicular to the axis;

at least one rim has an axial height that increases with distance from the circumferential rim;

the first outer surface of the flange comprises a flange according to the first embodiment and the second inner surface comprises a flange according to the second embodiment.

The subject of the invention is also a rotating electric machine comprising a rotor, a stator, a cooling chamber and a flange of this type.

The invention will be better understood from reading the following detailed description of non-limiting embodiments of the invention, and from examining the accompanying drawings.

Drawings

Fig. 1 schematically and partially shows a cross-sectional view of a rotating electric machine according to an embodiment of the present invention.

Fig. 2a is a perspective view of a flange according to the present invention.

Fig. 2b shows schematically and partly two adjacent edges according to the invention.

Fig. 2c schematically and partly shows two axially aligned rims according to the present invention.

Fig. 3 is a perspective view of the inside of the flange of fig. 2 a.

Figure 4 shows a cooling chamber according to the invention.

Detailed Description

The same reference numbers are used throughout the drawings to refer to the same, like or corresponding elements. It should also be noted that the various drawings are not necessarily to the same scale. Furthermore, the embodiments described below are in no way limiting. In particular, variants of the invention may be envisaged which comprise only a series of features described below, separate from the other features described. In particular, all variants and all embodiments described can be combined with one another if nothing is objected from a technical point of view to such a combination.

In the following description, the terms axial, radial, external and internal refer to the axis X of the machine, i.e. passing through the centre of the shaft 13. The axial direction corresponds to the axis X, while the radial direction corresponds to a plane converging on the axis X, in particular perpendicular to the axis X. The transverse plane is a plane perpendicular to the motor axis X. The side surfaces are surfaces of rotation extending around the X-axis of the motor. The thickness of the wall is defined by the distance between the two surfaces forming the wall, according to an axis perpendicular to the wall.

Fig. 1 shows a compact polyphase rotary electric machine 10, in particular for a motor vehicle. The rotating machine 10 converts mechanical energy into electrical energy in an alternator mode and is operable in a motor mode to convert electrical energy into mechanical energy. The rotating electrical machine 10 is, for example, an alternator-starter, a reversible electrical machine, or an electric motor.

The rotary electric machine 10 thus includes a housing 11. Inside the housing 11, it further comprises: a shaft 13 fitted to rotate about an axis X with respect to the casing; a rotor 12 that rotates integrally with the shaft 13; and a stator 15 surrounding the rotor 12. The rotary movement of the rotor 12 therefore takes place about the axis X.

The ribbed end of the shaft 13 makes it possible to ensure a mechanical connection of the motor to an external element in order to transmit a rotary motion to the shaft 13, or the shaft 13 to transmit its rotary motion.

The rotor 12 comprises a body in the form of a set of metal plates. The permanent magnet is implanted in the cavity of the body. The stator 15 comprises a set of bodies in the form of metal plates provided with recesses equipped with recess insulators for mounting connected electrical windings. The windings are electrically connected to the electronic control module.

As a variant, the rotor faces outwards, or the motor is an axial-flow motor.

The housing 11 comprises a front flange 16 and a rear flange 17 assembled to each other. At least one of the two flanges is made of a plastic material, and advantageously both flanges are made of a plastic material.

The description provided below refers to at least one of the two flanges made of plastic material, which may likewise be a front flange or a rear flange.

"Plastic flange" means a flange made of plastic or composite plastic material.

The flange shown in fig. 2 comprises a base 2 extending transversely to the axis X and provided at its centre with a housing for receiving a bearing. The flange 2 comprises a central opening 20 for the passage of the shaft 13. The flange further comprises a side wall 3 extending axially from the periphery of the base.

The inner surface of the flange will be defined hereinafter as the surface of the base and/or the side wall of the flange oriented towards the inside of the electric machine, i.e. towards the stator. The outer surface of the flange is defined as the surface of the base and/or the side wall of the flange oriented towards the outside of the electric machine.

A reinforcing rim 4 extends from the base 2 or side wall 3 of the flange. The surface from which the rim 4 extends is all or part of one of the inner or outer surfaces of the base or side wall of the flange.

The edge 4 advantageously extends substantially perpendicularly to said surface. As a variant, the rims 4 may extend in a direction inclined with respect to the direction perpendicular to the surface from which they extend.

In a first embodiment, shown in figure 2a, the base of the flange comprises, over its entire surface, a plurality of said reinforcing rims forming a reticular structure defining closed cavities. By "closed cavity" is meant a cavity having a closed perimeter in cross-section perpendicular to the axis of the machine. Volumetrically, the cavity is defined by a portion of the flange base and the reinforcing rim. The volume of the cavity is open in the axial direction on the side opposite the flange base. The "hollowed-out" flange with cavity is thus simultaneously relieved and hardened.

As a variant, it is possible to envisage a through cavity, i.e. a cavity delimited only by the reinforcing rim, and open axially on both sides, the base of the flange being pierced locally.

Generally, the cavities are substantially identical and regularly engage the surface.

In this first embodiment, the cross-section of the cavity in a cross-sectional plane perpendicular to the axis X has at least one axis of symmetry, for example in the case where the cross-section of the cavity is an isosceles triangle. Advantageously, the cross section of the cavity has at least two axes of symmetry. The cross-section of the cavity is for example triangular, oval, diamond-shaped or circular. In three-dimensional space, for example in this case, the cavity comprises two planes of symmetry, each containing the axis X.

The cavity advantageously has a hexagonal cross-section. In fact, the fact that each intersection of the grid extends for three branches significantly stiffens the base of the flange.

The base of the flange thus has a net structure defining a reinforcing rim of a so-called honeycomb stiffener structure.

However, the cavities at the edges of the flange base, i.e. at the junction of the base 2 and the central opening 20 or the junction of the base 2 and the side wall 3, are truncated, i.e. the cross-section of these cavities is not a complete hexagon. The truncated cavity is closed either by a rim forming the edge of the flange base 2 around its entire circumference or by a rim forming the edge of the flange base 2 at the central opening 20.

In an advantageous embodiment, the thickness of the at least one rim is between one quarter and one times the thickness of the base or the side wall extending therefrom, preferably about half the thickness of the base or the side wall extending therefrom. The distance between the flanges is about one to two times the thickness of the base of the flanges or the side walls extending therefrom.

The thickness of each rim is generally between 1 and 1.5mm, advantageously about 1.3mm. The thickness of the base 2 from which the rim 4 forming the cavity 40 extends is typically about half the thickness of the rim 4, as shown in figure 2 b. This therefore provides a flange which is easy to remove from the mould.

The axial height of the flange is about 4mm. The height of the flange is advantageously half to three times the thickness of the base. In the case where the thickness of the base is substantially uniform in its plane of extension, the rim has substantially the same height as the thickness of the base over its entire surface. As a variant, in the case of a variable thickness of the base 2, the thickness of the rim 4 can also be variable, so that the thickness of the rim 4 forming the cavity substantially approximates the thickness of the base 2 locally forming the cavity.

In the variant shown in fig. 2c, two axially aligned

rims

41, 42 extend from both sides of the base 2. Advantageously, the height of each rim is about half the axial height of the rim, which is necessary for the required hardening. The space associated with the presence of the rim 4 is therefore limited, since the given axial rim height required to harden the flange is distributed between the inside and the outside of the machine.

In a variant, the cavity 40 is present only on a portion of the base 2. The cavity is advantageously located, for example, on the peripheral surface of the base. As a variant, the cavity is located on the central surface of the base. This type of localization of the cavities makes it possible to optimize the distribution of the cavities in order to lighten and harden the flange, without however making it too fragile.

The honeycomb network may be located on the inner or outer surface of the flange base. In a variant, the honeycomb network may be located on the inner or outer surface of the side wall 3 of the flange.

In a second embodiment, shown in fig. 3, a plurality of radial rims 43 extend radially with respect to the axis X on the base 2 of the flange. These radial edges form reinforcing arms and are advantageously located on the inner surface of the flange base 2.

Said plurality of radial rims extending for example from the side wall 3 of the flange. More specifically, the lower end portion of the side wall 30 is defined as the portion of the side wall extending from the periphery of the base 2, in the portion thereof located axially near the base 2. A so-called peripheral radial rim extends from said lower end portion of the side wall 30 towards the axis X on the base of the flange. The edges 4 are angularly distributed around the axis X of the machine. An angle between 10 ° and 15 ° angularly separates two adjacent edges. This type of separation angle between the rims allows for optimum stiffening without making the flanges too heavy. The angle between two adjacent edges is substantially the same around the entire axis. The rim is positioned on a surface of the base that defines a peripheral crown about the motor axis X.

The base 2 of the flange also comprises a circumferential rim 44. The circumferential rim extends axially around the axis of the machine and intersects at least a portion of the first plurality of radial rims 43. Thus, the cavity 40 is defined by a portion of the lower end portion of the side wall 30 and by portions of the two peripheral radial reinforcing rims 43 and the circumferential rim 44. The cavities defined by the plurality of rims all have substantially the same dimensions and the same geometry.

For moulding reasons, the eyelets axially pierced at the circumferential edge make it possible to reduce the weight of the flange and to ensure a constant material thickness. Sudden changes in material thickness or large thicknesses can lead to difficulties in forming due to temperature changes in the mould and thus risk shrinkage cavities or material loss.

In combination, the second plurality of radial rims extend around the axis X of the electric machine. The second plurality of rims are angularly distributed about the axis of the electric machine on the surface of the base defining a central crown about the axis X.

The central opening 20 advantageously comprises a plastic hub 21. The plastic hub extends transversely to the base 2 of the flange in the axial direction, forming a sleeve. The plastic hub comprises an element made of metal. The bearing that supports the shaft is pressed into this element made of metal. As a variant, a hub comprising an element made of metal is overmoulded onto the bearing. The element made of metal makes possible a good reliability of the front bearing and a good control of the clamping of the bearing in the hub.

A second plurality of so-called central radial rims 45 extend from the hub 21 towards the side wall 3 on the base 2 of the flange.

At least part of the central radial edge intersects the circumferential edge 44. The cavity 4 is thus defined by a portion of the hub 21 and by portions of the two central radial reinforcing rims 45 and the circumferential rim 44. The cavities defined by the plurality of rims are all substantially the same size and the same geometry.

The ratio between the number of peripheral radial rims 43 and the number of central radial rims 45 is advantageously about 1.5.

As a variant, the flange comprises a plurality of circumferential rims 44 positioned concentrically about the axis X. This type of rim 44 intersects the

radial rims

43, 45, thereby defining a plurality of cavities 40.

The axial height of the

rims

43, 45 decreases between the wall from which they extend (i.e. the side wall 2 or the hub 21) and the circumferential rim 44. For example, the axial height of the rim decreases exponentially between the wall from which it extends and the circumferential rim. The circumferential rim typically has a height of about a few millimetres, typically 10mm.

More specifically, in the radial direction, the profile of the central radial rim 45 has a portion of constant axial height starting from the hub 21, followed by a portion of exponential decrease in axial height until reaching the axial height of the circumferential rim 44 at the junction of the radial rim 45 and the circumferential rim 44.

In the preferred embodiment, the flange has a "honeycomb" network structure on its outboard base face 2 and reinforcing arms on its inboard base face.

As a variant, the rim forms an open cavity.

The above-mentioned plastic flange is advantageously obtained by moulding. The joints between the base 2 and the hub 21 or between the base 2 and the side wall 3 are slightly rounded and do not have a projecting angle. In this type of flange obtained by moulding, the rim 4 is therefore integral with the base 2 of the flange.

In order to meet the requirements of resistance to thermal stresses, it is envisaged to add auxiliary elements to the plastic. Typically, thermoplastic materials, or thermosetting plastic materials, or fiber-filled plastics, such as mechanical textile fibers, or fillers, such as carbon, graphite, fiberglass, aluminum, or copper, are used. As a variant, the plastic material is reinforced with a reinforcing element, such as a metal, for example aluminum, or a metal alloy, at the base or skirt of the flange. As a variant, the plastic is reinforced by carbon or textile fibres or animal or plant fibres such as spider silks or tendons or kevlar fibres or hemp. These stiffening elements provide a highly localized stiffening in the regions subjected to particularly high stresses. Furthermore, this type of metal addition must be carried out, for example, in very small proportions, so as not to risk making the weight of the flange heavier.

In view of the foregoing description of the front flange 16, the rear flange 17 further comprises a base provided at its center with a housing for receiving the rear bearing, and a side wall extending axially towards the side wall of the front flange. The front and rear flanges are integral with one another to form all or a portion of a housing that houses the motor.

The

flanges

16, 17 may be fixed to each other or to the intermediate part by fixing units, such as screws, which pass through perforation holes extending radially from the side wall of the flange and are designed to cooperate with corresponding threaded holes provided in holes extending radially from the side wall of the other flange or intermediate part.

Since the plastic is thermally insulating, cooling by a liquid, such as oil or water, is advantageously provided.

In an advantageous configuration of the machine shown in fig. 4, the front plastic flange 16 may advantageously have a transverse double wall forming a cooling chamber 160.

More specifically, the side wall of the front flange is formed by two radially concentric annular walls around the axis X, namely a radially inner wall 31 and a radially outer wall 32. The radially inner wall 31 is positioned facing the winding and the radially outer wall 32 is positioned facing the outside. Each

wall

31, 32 extends along the axis X in an annular form between one end connected to the base 2. The two walls of such a double wall are connected to each other at the base. The free ends of the inner and outer walls are ends that are not connected to each other and are not connected to the transverse wall.

The rear flange 17 has for example only a base in the form of a side wall without extensions. The side walls of the front flange 3 cover the stator 15 along the entire height of the stator 15, the rear flange 17 is a cover without side walls, the latter having no covering surface around the axis X.

The cooling chamber 160 is thus housed in the side wall of the front flange between two concentric walls. The base of the rear flange 17 bears against a peripheral region on the free end of the side wall of the front flange, opposite the base of the front flange. The cooling fluid circulates between the two concentric walls.

The concentric outer wall 32 advantageously has a reinforcing rim 4 which at least partially forms a honeycomb structure. This therefore limits the magnetic noise.

Claims

1. A plastic flange for a rotary electric machine having an axis X, comprising a base (2) extending transversely to the axis X and a side wall (3) extending axially from the periphery of the base, characterized in that at least one of the base (2) and the side wall (3) has a surface from which at least one reinforcing rim (4) extends.

2. The plastic flange according to claim 1, obtained by moulding.

3. A plastic flange according to any one of the preceding claims, comprising a plurality of rims (4) defining closed cavities.

4. The flange according to claim 3, wherein the cavities (40) are substantially identical to each other.

5. The flange according to any one of the preceding claims, wherein a cross-section of the cavity (40) in a plane transverse to the axis X has at least two axes of symmetry.

6. A flange according to any one of the preceding claims, wherein the cavity (40) has a hexagonal cross-section.

7. A flange according to any one of the preceding claims, wherein the thickness of at least one rim (4) is between one quarter and one times the thickness of the base (2) or the side wall (3) extending therefrom, and preferably about half the thickness of the base or the side wall extending therefrom.

8. A flange according to any one of the preceding claims, wherein the axial height of at least one rim (4) is between half and three times the thickness of the base (2) or the side wall (3) extending therefrom, and preferably approximately the thickness of the base or the side wall extending therefrom.

9. A flange according to any one of the preceding claims, wherein the surface is an outer surface, the flange further comprising an inner surface from which also extends a further plurality of rims, at least one rim of the outer surface (41) being axially aligned with at least one rim of the inner surface (42).

10. A plastic flange as claimed in claim 3, further comprising a central opening (20) for the passage of a shaft and a hub (21) extending from the central opening, and wherein the cavity is formed on the base of the flange:

first by one or more from two more of:

a plurality of peripheral radial rims (43) extending radially from said side wall with respect to the axis of the machine;

and a plurality of central radial rims (45) extending radially from the rim with respect to the axis of the machine;

followed by a circumferential rim (44) extending transversely to the plurality of radial rims (43, 45) about the axis of the machine.

11. The flange of claim 10, comprising:

a plurality of central radial rims (45);

and a plurality of peripheral radial rims (43);

the ratio between the number of peripheral radial edges and the number of central radial edges is between 1 and 2, preferably equal to 1.5.

12. The flange of any one of claims 10 to 11, wherein two angularly adjacent edges of one of the plurality of edges are angularly separated by an angle of substantially between 10 ° and 15 °, the angle being measured from the axis X in a plane perpendicular to the axis.

13. The flange according to any one of claims 10 to 12, wherein at least one of said rims (43, 45) has an axial height that increases with distance from said circumferential rim.

14. A flange according to any one of the preceding claims, wherein the first outer surface comprises a flange according to any one of claims 4 to 8 and the second inner surface comprises a flange according to any one of claims 10 to 13.

15. A rotating electrical machine comprising a rotor, a stator, a cooling chamber and a flange according to any one of the preceding claims 1 to 14.