WO2021099533A1

WO2021099533A1 - Rotary electric machine with axial immobilization of the stator

Info

Publication number: WO2021099533A1
Application number: PCT/EP2020/082812
Authority: WO
Inventors: Jean-Luc Tarrago; Khalid Sassane; Alain Defebvin; Rafael SANTOS; Matthieu BONNICI; Mohammed Krikeb
Original assignee: Valeo Equipements Electriques Moteur
Priority date: 2019-11-22
Filing date: 2020-11-20
Publication date: 2021-05-27
Also published as: FR3103653A1

Abstract

The present invention provides a rotary electric machine having a stator (15) extending about an axis (X) and having a stator body (27) having an annular yoke (40) from which there extend teeth that form a succession of slots and an electric winding (28) accommodated at least partially in said slots, a casing (11) that is arranged so as to surround the stator, at least partially, and comprises a first flange and a second flange, each flange having a plate (37) that extends generally transversely with respect to the axis and a skirt (38) that extends generally axially from the plate, the skirt having a groove (39). The stopping element (41) is arranged between the yoke and the skirt of the first flange so as to immobilize the stator in an axial direction with respect to said flange, the stopping element being in abutment in the groove of said skirt.

Description

Title of the invention: Rotating electric machine with axial locking of the stator

[0001] The invention relates in particular to a rotating electrical machine with axial locking of the stator in the housing of said machine, in particular for a motor vehicle.

[0002] The invention finds a particularly advantageous application in the field of rotating electrical machines such as alternators, alternator-starters or even reversible machines or electric motors. It is recalled that a reversible machine is a rotating electrical machine capable of working in a reversible manner, on the one hand, as an electric generator in alternator function and, on the other hand, as an electric motor for example to start the heat engine of the motor vehicle. .

[0003] A rotating electrical machine comprises a rotor movable in rotation about an axis and a fixed stator. In alternator mode, when the rotor is rotating, it induces a magnetic field in the stator which transforms it into electric current to supply the vehicle's electrical consumers and to recharge the battery. In motor mode, the stator is electrically supplied and induces a magnetic field driving the rotor in rotation, for example to start the heat engine.

[0004] The stator comprises a body forming a series of notches through which an electric coil extends axially on either side of the body to form parts called chignons. The stator body is mounted in two flanges forming the housing of the rotating electrical machine. Conventionally, each of the flanges has a retaining portion extending over the entire circumference of the stator body.

When the size of the electric machine is limited and the stator has a large diameter, the chignons can be radially very close to the flanges and this can cause short circuits during the operation of the rotating electric machine. The present invention aims to make it possible to avoid the drawbacks of the prior art. In particular, the invention aims to provide a rotating electrical machine with small radial bulk, the chignons of which are sufficiently far from the flanges not to create a short-circuit while ensuring effective maintenance of the stator by the flanges.

To this end, the present invention therefore relates to a rotary electrical machine comprising a stator extending around an axis and comprising a stator body having an annular yoke from which extend teeth forming a succession of notches and an electrical coil housed at least partially in said notches, a housing arranged to surround, at least partially, the stator and comprising a first flange and a second flange, each flange having a plate extending generally transversely with respect to to the axis and a skirt extending generally axially from the plate, the skirt having a groove. According to the invention, a stopper element is arranged between the cylinder head and the skirt of the first flange so as to form a blocking in an axial direction of the stator with respect to said flange, the stopper element being supported in the groove. of said skirt.

[0008] The stop element makes it possible to prevent any movement of the stator body in an axial direction with respect to the flange as well as any rotation of the stator body about its axis. In addition, the stop element also makes it possible to move the stator away from the flange, which prevents the creation of a short circuit while ensuring axial immobilization of the stator relative to the housing without increasing the radial size of the machine. . Indeed, the addition of this additional element makes it possible to compensate for the small radial size available which can generate short circuits by allowing the use of a stator of larger diameter in a flange of reduced diameter to thus optimize the performance of the machine. rotating electric.

[0009] According to one embodiment, the stop element has an annular shape. This distributes the axial retention forces over the entire circumference of the stator and prevents unbalance of the machine.

[0010] According to one embodiment, the stop element is formed from a metallic material or from an alloy of metallic materials. This improves the rigidity of the part and to avoid creep phenomena. This also makes it possible to improve the heat dissipation from the stator body to the stop element by conduction.

[0011] According to one embodiment, the stop element is interposed between a portion of the yoke of the stator body and a portion of the skirt of the first flange. In particular, at least a portion of the stop element is arranged radially between the cylinder head and the groove.

[0012] More particularly, the stop element can be in contact only with one of the flanges and in particular here the first flange.

[0013] According to one embodiment, the stop element is in contact in an axial direction and in a radial direction with the skirt of the first flange.

[0014] According to one embodiment, the stop element is an attached part in said rotating electrical machine. This makes it possible to simplify the manufacture of the stator body and of the flanges while retaining generic elements while allowing the performance of the rotating electrical machine to be optimized and while maintaining a small footprint.

[0015] According to one embodiment, the stop element has a section, in a plane comprising the axis, in the form of an L. More precisely, the stop element comprises a first portion extending radially between the cylinder head and the groove and a second portion extending axially between said cylinder head and said groove. This improves the precision of the axial locking of the cylinder head while simplifying the mounting of the stop element in the machine before final assembly.

[0016] According to an alternative embodiment, the stop element is made from material with the cylinder head. The stop element then forms a shoulder which cooperates with the groove to axially block the stator body. This makes it possible to reduce the duration of the machine assembly process by avoiding the need for an additional part.

For example in this alternative embodiment, an axial end of the stop element bears against the skirt of the second flange. This makes it possible to avoid axial displacement of the stop element and improves the transmission of locking force. [0018] According to one embodiment, the machine further comprises an electronic assembly comprising at least one power module, said electronic assembly being mounted on the first flange. In other words, the stop element is arranged between the yoke of the stator and the rear flange of the machine. This makes it possible to improve the cooling of the machine compared to an architecture where said element is mounted between the cylinder head and the front flange, in particular in the event of shrinking of the cylinder head in one of the flanges.

[0019] According to one embodiment, the yoke of the stator body has a hooping zone with the second flange. The retaining force exerted by the shrinkage in combination with that exerted by the stopper improves the locking in an axial direction as well as the rotational locking of the stator body while improving the cooling of said body.

[0020] The rotating electric machine can advantageously form an alternator, an alternator-starter, a reversible machine or an electric motor.

[0021] The present invention may be better understood on reading the detailed description which follows, of non-limiting examples of implementation of the invention and of the examination of the accompanying drawings.

[0022] [Figure 1] shows, schematically and partially, a sectional view of a rotary electrical machine according to an exemplary implementation of the invention.

[0023] [Figure 2] shows, schematically and partially, a sectional view of the machine according to an example of a first embodiment of the invention.

[0024] [Figure 3a] shows, schematically and partially, a perspective view of the stop element of Figure 2.

[0025] [Figure 3b] shows, schematically and partially, a perspective view in section of part of the stop member of Figure 3a.

[0026] [Figure 4] shows, schematically and partially, a sectional view of the machine according to an example of a second embodiment of the invention. [0027] [Figure 5] shows, schematically and partially, a side view of the stator body comprising the stop element of Figure 4.

Identical, similar or analogous elements retain the same references from one figure to another. It will also be noted that the different figures are not necessarily on the same scale. In addition, the embodiments which are described below are in no way limiting; it is in particular possible to imagine variants of the invention comprising only a selection of characteristics described below isolated from the other characteristics described.

FIG. 1 represents an example of a compact and polyphase rotary electrical machine 10, in particular for a motor vehicle. This machine 10 converts mechanical energy into electrical energy, in alternator mode, and can operate in motor mode to transform electrical energy into mechanical energy. This rotary electric machine 10 is, for example, an alternator, an alternator-starter, a reversible machine or an electric motor.

In this example, the machine 10 comprises a housing 11. Inside this housing 11, it further comprises a shaft 13, a rotor 12 integral in rotation with the shaft 13 and a stator 15 surrounding the rotor 12. The rotational movement of the rotor 12 takes place around an axis of rotation X. In the remainder of the description, the axial direction corresponds to the axis X, passing through the shaft 13 at its center, while the radial orientations correspond to concurrent planes, and in particular perpendicular, to the X axis. For radial directions, the internal designation corresponding to an element oriented towards the axis, or closer to the axis with respect to a second element , the external name designating a distance from the axis.

In this example, the housing 11 comprises a front flange 16 and a rear flange 17 which are assembled together in particular via fixing means such as tie rods. These flanges 16, 17 are of hollow shape and each carry, centrally, a bearing coupled to a respective ball bearing 18, 19 for the rotational mounting of the shaft 13. In addition, the housing 11 comprises fixing means 14 allowing the assembly of the rotary electric machine 10 in the vehicle.

A drive member such as a pulley 20 can be fixed on a front end of the shaft 13. This member makes it possible to transmit the movement of rotation to the shaft or shaft to transmit its rotational motion to the belt. In the remainder of the description, the front / rear denominations refer to this member. Thus a front face is a face oriented in the direction of the member while a rear face is a face oriented in the opposite direction of said member.

The rear end of the shaft 13 carries, here, slip rings 21 belonging to a collector 22. Brushes 23 belonging to a brush holder 24 are arranged so as to rub on the slip rings 21. The holder -brush 24 is connected to a voltage regulator (not shown).

The front flange 16 and the rear flange 17 may include substantially lateral openings for the passage of an air flow in order to allow the cooling of the machine 10 by air circulation generated by the rotation of a front fan 25 arranged on a front axial face of rotor 12 and a rear fan 26 arranged on a rear axial face of said rotor. Alternatively, the housing 11 may include a chamber allowing the passage of a cooling liquid and include openings allowing the passage of an additional air flow or not include said openings.

In this example, the rotor 12 is a claw rotor comprising two pole wheels 31. Each pole wheel 31 is formed of a plate 32 oriented transversely, of a plurality of claws 33 forming magnetic poles and a cylindrical core 34. The rotor has a coil 35 wound around the core. For example, the slip rings 21 belonging to the collector 22 are connected by wire connections to said coil 35. The rotor 12 can also include magnetic elements, such as permanent magnets, interposed between two adjacent claws 33. Alternatively, the rotor can be formed from a bundle of sheets housing permanent magnets forming the magnetic poles.

In this exemplary embodiment, the stator 15 comprises a body 27 formed from a bundle of sheets. The stator body has a yoke 40 of generally annular shape from which radially extend teeth. Each of the spaces between two adjacent teeth forms a notch. Each notch is equipped with notch insulation and is traversed by a portion of an electrical coil 28. The coil has a portion inserted into the various notches of the body 27 and a portion extending outside said notches. forming a front bun 29 and a rear bun 30 on either side of the body of the stator. Furthermore, the coil 28 is formed of one or more phase (s) comprising at least one electrical conductor and being electrically connected to an electronic assembly 36.

The electronic assembly 36 which is here mounted on the housing 11, comprises at least one electronic power module making it possible to control at least one phase of the winding 28. The power module forms a voltage rectifier bridge to transform the voltage alternating generated in a direct voltage and vice versa.

Each of the flanges 16,17 of the housing 11 comprises a plate 37 extending transversely with respect to the X axis in a generally disc shape with a central opening for the passage of the shaft 13. Each of said flanges comprises also a skirt 38 extending axially from an outer radial end of the associated plate. The skirt generally has the shape of a hollow cylinder. The skirt 38 of the rear flange 17, called the first flange, comprises a groove 39 forming a notch in the internal surface of said skirt.

The groove extends at an axial end of the skirt and in particular at the axial end facing the skirt 38 of the front flange 16, called the second flange. Thus, the axial end of the skirt has a thickness in a reduced radial direction, due to the groove 39, relative to the rest of the skirt. The groove forms a groove which extends circumferentially, in particular, over the entire periphery of the skirt.

The machine comprises at least one stop element 41 making it possible to avoid any movement, in particular in an axial direction, of the stator body 27.

The stop element 41 is arranged between the cylinder head 40 and the skirt 38 of the rear flange 17. In particular, the stop element is housed in the groove 39 of said skirt. For example, said stop element has a shape complementary to the shape of the groove 39.

Figures 2, 3a and 3b illustrate a first embodiment of the stop element 41. In this first embodiment, the stop member is an attached part in said rotary electrical machine. In other words, the stop element is an additional part to the stator body and to the flange which is not integral with one of said elements.

[0042] In the example described here, the stop element 41 has an annular shape. The stop element 41 may have a section, in a plane comprising the X axis, in the form of an L. More precisely, the stop element comprises a first portion 42 extending radially between the cylinder head 40 and the groove 39 and a second portion 43 extending axially between said cylinder head and said groove. The first portion extends in a radial direction from one end of the second portion to form the L-shaped section. Preferably, the first portion and the second portion are integral.

In the example illustrated, the stop element 41 is arranged radially and axially between the cylinder head 40 and the groove 39 of the skirt of the rear flange 17.

The first portion 42 extends in a radial direction projecting from the skirt 38 of the flange so as to form a stop against which an axial end of the cylinder head 40 bears.

The second portion 43 preferably has a thickness in a radial direction greater than the radial thickness of the groove 39. Thus, an internal face of the second portion is arranged radially closer to the axis of rotation X an internal surface of the skirt 38 and in particular an internal surface of said skirt extending opposite the rear bun 30. The free axial end of the second part 43 of the stop element extends, preferably, at a distance from the skirt 38 of the front flange 16.

The axial end of the skirt 38 of the rear flange 17 is preferably in contact with the axial end of the skirt 38 of the front flange 16 after the assembly and final tightening of the two flanges between them.

The second portion 43 has a height, in an axial direction, greater than a length, in a radial direction, of the first portion 42.

[0048] The stopper 41 may be formed from a metallic material or from an alloy of metallic materials such as steel or aluminum.

The stop element 41 can be mounted tight in particular by fitting into the groove 39 of the rear flange 17. Figures 4 and 5 illustrate a second embodiment of the stop element 41. In this second embodiment, the stop element 41 is made from material with the cylinder head 40 so as to be in one piece . The stop element then forms a shoulder projecting radially from the cylinder head and coming to cooperate with the groove to axially block the stator body. The yoke 40 associated with the stop element 41 then has a thickness in a radial direction greater than the radial thickness of the yoke alone.

In the example described here, the stop element 41 extends over the entire circumference of the cylinder head 40. The stop element 41 may have a rectangular section, in a plane comprising the X axis A height, in an axial direction, of the stop member 41 may be greater than a length, in a radial direction, of said member. This makes it possible to simplify the manufacture of the stator body comprising such an element.

In the example illustrated, the stop element 41 is arranged only radially between the cylinder head 40 and the groove 39 of the skirt of the rear flange 17.

The front axial end of the stop element 41, that is to say the axial end opposite axially to the axial end resting against the groove 39, may be resting against the skirt 38 of the front flange 16. In this example, the stop element 41 is thus clamped between the groove 39 of the skirt 38 of the rear puddle 17 and the free axial end of the skirt 38 of the front flange 16.

The stop element 41 is here formed from the same material as the stator body. Said material is in particular a metallic material or an alloy of metallic materials such as steel. For example, the stop element 41 is formed by several protuberances each made on a sheet and stacked axially on top of each other to form the stator body 27. Alternatively, the stop element 41 can be formed by machining of the outer surface of the stator body.

In an exemplary embodiment applicable to the first and to the second embodiment described above, the yoke 40 of the stator body 27 has a hooping zone 44 with the front flange 16. In particular, a portion of the outer surface of the cylinder head 40 is shrunk in a portion of the internal surface of the skirt 38 of the front flange. The present invention finds applications in particular in the field of alternators or reversible machine or electric motor, but it could also be applied to any type of rotating machine.

Of course, the above description has been given by way of example only and does not limit the scope of the present invention, which would not be departed from by replacing the various elements with all other equivalents. In the above description, the groove is arranged in the skirt of the rear flange. Alternatively, the groove could be arranged in the front flange and the stop element could then be arranged between the stator body and the front flange without departing from the scope of the invention. The rear flange could then present the hooping zone with the stator body. In another alternative, the two front and rear flanges could each have a groove. The machine could then have two stop elements each arranged between one of the respective flanges and the stator body.

Claims

Claims Rotating electric machine comprising: a. a stator (15) extending around an axis (X) and comprising a stator body (27) having an annular yoke (40) from which extend teeth forming a succession of notches and a winding electrical (28) housed at least partially in said notches, b. a housing (11) arranged to surround, at least partially, the stator and comprising a first flange and a second flange, each flange having a plate (37) extending generally transversely with respect to the axis (X) and a skirt (38) extending generally axially from the plate, the skirt having a groove (39); vs. the machine (10) being characterized in that a stop element (41) is arranged between the yoke (40) and the skirt (38) of the first flange so as to form a blockage in an axial direction of the stator with respect to said flange, the stop element (41) being supported in the groove (39) of said skirt. Machine according to the preceding claim, characterized in that the stop element (41) has an annular shape. Machine according to any one of the preceding claims, characterized in that the stop element (41) is formed of a metallic material or of an alloy of metallic materials. Machine according to any one of the preceding claims, characterized in that at least a portion of the stop element (41) is arranged radially between the yoke (40) and the groove (39). Machine according to any one of the preceding claims, characterized in that the stop element (41) is an attached part in said rotating electrical machine. Machine according to the preceding claim, characterized in that the stop element (41) has a section, in a plane comprising the axis (X), in the form of an L. Machine according to any one of Claims 1 to 4, characterized in that the stop element (41) is made from material with the cylinder head (40). Machine according to the preceding claim, characterized in that an axial end of the stop element (41) bears against the skirt (38) of the second flange. Machine according to one of the preceding claims, characterized in that it further comprises an electronic assembly (36) comprising at least one power module, said electronic assembly being mounted on the first flange. Machine according to any one of the preceding claims, characterized in that the yoke (40) of the stator body has a hooping zone (44) with the second flange.