FR3074978A1 - ROTATING ELECTRIC MACHINE WITH HOLDING BITS FOR PERMANENT MAGNET SPRINGS - Google Patents

Abstract

The invention relates mainly to a rotating electrical machine, in particular for a motor vehicle, for example for a motor vehicle air conditioning compressor, comprising: - a stator, - a rotor (12) comprising a body (21) provided with cavities (28). ) and at least one permanent magnet (33) disposed inside a cavity (28), - a spring (40) for holding the permanent magnet (33) positioned inside the cavity (28) characterized in that - the rotor body (21) has at least one retaining stop (44) arranged to hold an end portion of the holding spring (40), - the retaining stop (44) being disposed between a bottom face of the cavity (28) and the magnet (33), - the end portion of the holding spring (40) being disposed between the bottom of the cavity (28) and the holding stop (44) .

Description

ROTATING ELECTRICAL MACHINE PROVIDED WITH HOLDERS FOR PERMANENT MAGNET SPRINGS

The present invention relates to a rotary electrical machine provided with holding stops for springs of permanent magnets. The invention finds a particularly advantageous application in the field of rotating electrical machines, such as an alternator or an electric motor. The invention can be advantageously used with an air conditioning refrigerant compressor for a motor vehicle.

Electric machines are known comprising a stator and a rotor secured to a shaft ensuring the setting in motion of a scroll compressor, the latter being designated by the name of scroll in English. Such a system comprises two spirals cooperating with each other to pump and compress the refrigerant. In general, one of the spirals is fixed, while the other moves eccentrically without turning, so as to pump then trap and compress pockets of fluid between the turns. Such a system is for example described in the document EP1865200.

The stator has a body made of laminated sheets to reduce eddy currents. The body has an annular wall, called the cylinder head, and teeth from the inner periphery of the annular wall. The stator teeth distributed on the cylinder head extend towards the inside of the stator in the direction of the rotor. The teeth define with the cylinder head notches open towards the inside and intended to receive a winding for the formation of a polyphase stator, for example of the three-phase type. This winding could for example consist of a set of coils electrically isolated from the body of the stator each wound around a corresponding tooth. A so-called concentrated type winding is thus obtained.

Furthermore, the rotor comprises a body formed by a stack of sheets of metal sheets held in the form of a package by means of a suitable fixing system. The rotor has poles formed for example by permanent magnets located in cavities formed in the magnetic mass of the rotor.

It is important to effectively maintain the magnets inside the cavities of the rotor, taking into account the centrifugal force which is liable to damage the magnets. In addition, when the magnets are inserted into the cavities of the rotor, the magnets are attracted to the center by a magnetic phenomenon. There is therefore a need to install a spring inside each cavity receiving one or more magnets. The invention aims to maintain such a spring before inserting the magnet (s) into the corresponding cavity.

To this end, the subject of the invention is a rotary electrical machine, in particular for a motor vehicle, for example for a motor vehicle air conditioning compressor, comprising:

- a stator,

- a rotor comprising a body provided with cavities and at least one permanent magnet disposed inside a cavity,

- a spring for holding the permanent magnet positioned inside the cavity, characterized in that

the rotor body has at least one retaining stop arranged to hold an end portion of the retaining spring,

the retaining stop being disposed between a bottom face of the cavity and the magnet,

- The end portion of the retaining spring being disposed between the bottom of the cavity and the retaining stop.

According to one embodiment, the retaining spring consists of a corrugated strip.

According to one embodiment, the retaining stop has two end edges, each end edge being connected to a lateral face of the cavity.

According to one embodiment, the retaining stop comprises a junction arm, said junction arm being connected on the one hand to the bottom face of the cavity and on the other hand to the retaining stop.

According to one embodiment, the retaining stop comprises two end flanges projecting on either side of the junction arm. Alternatively, the end flanges of the stopper are connected to the lateral faces of the cavity.

According to one embodiment, the retaining spring has a fork-shaped end portion comprising two legs arranged on either side of the junction arm.

According to one embodiment, the rotor body comprises at least one wall extending axially along at least a portion of the bottom face of the cavity.

According to one embodiment, the wall extends along substantially the entire height of the cavity.

According to one embodiment, the wall extends opposite a corrugated portion of the retaining spring, said corrugated portion coming to bear against the wall.

According to one embodiment, an end portion of the retaining spring is disposed between the wall and the retaining stop.

According to one embodiment, the wall has a part forming the junction arm of the retaining stop.

According to one embodiment, the rotor body is formed by a pack of sheets formed by a stack of ferromagnetic sheets.

According to one embodiment, the retaining stop is formed by a plurality of sheets of the sheet pack.

According to one embodiment, the rotor body comprises two types of sheets to form the sheet pack, a first type of sheet comprising a portion of the retaining stop, a second type of sheet being devoid of portion of the retaining stop.

According to one embodiment, the retaining stop extends substantially in a plane parallel to a face of the permanent magnet against which the bearing spring bears.

According to one embodiment, the permanent magnets extend radially with respect to an axis of the rotor.

According to one embodiment, the rotor body has two retaining stops at each of its ends. Alternatively, the retaining spring has a fork-shaped end situated on either side of the joining arm and a solid end situated in a space between the retaining stop and the wall.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given only by way of illustration but in no way limit the invention.

Figure 1 is a cross-sectional view of a rotary electrical machine according to the present invention;

Figure 2 is a perspective view illustrating a first embodiment of the rotor according to the present invention;

Figures 3 and 4 are perspective and sectional views showing the retaining stops of the rotor of Figure 2;

Figure 5 is a perspective view of a spring used in the rotor of Figure 2;

Figure 6 is a perspective view in section illustrating a second embodiment of a rotor according to the present invention;

Figure 7 is a detailed perspective view showing the retaining stops of the rotor of Figure 6;

FIG. 8 is a perspective view of a spring used in the rotor of FIG. 6.

Identical, similar, or analogous elements keep the same reference from one figure to another.

FIG. 1 represents a rotary electrical machine 10 comprising a polyphase stator 11 surrounding a rotor 12 of axis X intended to be mounted on a shaft (not shown). The stator 11 is intended to be carried by a casing (not shown) configured to carry the shaft in rotation via ball and / or needle bearings. This electric machine 10 may belong to a compressor used for the compression of the refrigerant fluid of air conditioner of a motor vehicle. Alternatively, the electric machine 10 can operate in alternator mode. Preferably, the electric machine 10 is configured to operate at a voltage below 350Volts.

The stator 11 comprises a body 14 in the form of a packet of laminated sheets having at its external periphery an annular wall 15, called the cylinder head, and teeth 16 coming from the internal periphery of the cylinder head 15. These teeth 16 are distributed circumferentially in a regular manner and extend inwards in the direction of the rotor 12 described in more detail below.

The teeth 16 delimit notches 17. These teeth 16 each have at their free end two flanges extending circumferentially on either side of the tooth. The free ends of the teeth delimit an air gap with the external periphery of the rotor 12 of the electric machine 10.

The stator 11 further comprises a winding, for example three phase, comprising a plurality of coils 19 to form the different poles of the stator 11. Each coil 19 is formed by a plurality of turns surrounding a corresponding tooth 16. The coils 19 are produced so that the same notch 17 receives two half-coils. A so-called concentrated type winding is thus obtained.

Furthermore, as can be seen in FIG. 2, the rotor 12 of axis X comprises a body 21 formed by a packet of laminated sheet formed by a stack of ferromagnetic sheets 22. The rotor body 21 comprises a hub 24 intended to be mounted on the machine shaft and teeth 25 extending radially relative to the hub 24. Cavities 28 are located between the teeth 25. Each cavity 28 is delimited by two consecutive teeth 25, so that there are a circumferential alternation between the teeth 25 and the cavities 28. The cavities 28 open axially on either side of the rotor body 21.

In the example shown, each tooth 25 has two link arms 29 to the hub 24. A recess 30 is formed between the arms 29 of the same corresponding tooth 25 to lighten the rotor 12 and maximize the magnetic performance.

Each tooth 25 further comprises a fixing hole capable of receiving a fixing member 32, such as a rivet, to hold the sheets 22 of the rotor 12 together.

At least one permanent magnet 33 is positioned in each cavity 28. Thus, it will be possible to use a single magnet 33 positioned inside a cavity 28, or two magnets 33 or even more than two magnets 33 per cavity 28 stacked axially on top of each other.

Flanges (not shown) may be fixed on the axial ends of the rotor body 21 in order to axially retain the magnet (s) 33 inside each cavity 28. Fixing holes 35 may be provided in the rotor body 21 to allow the passage of flange fixing members.

The permanent magnets 33 extend radially with respect to the axis X of the rotor 12. This gives a rotor 12 configuration with flux concentration, the lateral faces facing two consecutive magnets 33 having the same polarity . The magnets 33 are preferably made of rare earth. As a variant, the magnets 33 are made of ferrite depending on the applications and the desired power of the electric machine 10. In this case, the rotor 12 has ten poles.

In addition, lips 38 are implanted on the side of the free end of each tooth 25. These lips 38 extend on either side of each tooth 25. These lips 38 thus constitute means for radially retaining the magnets 33 Alternatively, the cavities 28 for the magnets 33 may be closed at their outer periphery. It is then a rotor configuration 12 with buried permanent magnets.

A retaining spring 40 of the magnet 33 is disposed inside a corresponding cavity 28. The retaining spring 40 advantageously takes the form of a corrugated strip at low cost. As can be seen in FIG. 5, the spring 40 includes alternating domed portions 41 and hollow portions 42 intended to be located opposite a corresponding magnet 33.

The retaining spring 40 ensures the plating of the magnet (s) 33 of the cavity 28 against the corresponding lips 38. Where appropriate, a retaining plate, known as a laminate, may be interposed radially between the magnet 33 and the lips 38.

In addition, the rotor body 21 has a stop 44 arranged to hold an end portion 48 of the retaining spring 40. The stop 44 is disposed between the magnet 33 and a bottom face 45 of the cavity 28 disposed on the side. of the shaft of the electric machine 10. An end portion 48 of the retaining spring 40 is disposed between the bottom face of the cavity 28 and the retaining stop 44.

In the embodiment shown in FIGS. 3 and 4, a wall 46 extends axially along at least a portion of the bottom face 45 of cavity 28. The wall 46 advantageously extends substantially along the entire height of the cavity 28. The wall 46 extends opposite a corrugated portion 49 of the spring 40 extending between two end portions 48, so that the corrugated portion 49 comes to bear against the wall 46.

A full end portion 48 of the spring 40 is disposed between the wall 46 and the retaining stop 44. According to this embodiment, the stop 44 has two end edges, each end edge being connected to a side face of the cavity 28. The stop 44 extends substantially in a plane parallel to the face of the magnet 33 against which the spring 40 bears.

Advantageously, the rotor body 21 has two stops 44 per cavity 28, a stop 44 being positioned at each of the axial ends of the rotor body 21. Thus, before inserting the magnet (s) 33 inside a cavity 28, each end portion 48 of the spring 40 is placed between the wall 46 and a corresponding stop 44. The magnet (s) 33 are then inserted into the cavity 28, so that the spring 40 is compressed between the magnet (s) 33 and the wall 46 and exerts by reaction a radial force making it possible to hold the magnet (s) 33 inside. of the cavity 28.

In the embodiment shown in FIGS. 6 and 7, the retaining stop 44 comprises a joining arm 50. This joining arm 50 is connected on the one hand to the bottom face 45 of the cavity 28 and on the other leaves at the stop 44. The junction arm 50 is advantageously located in a central zone of the stop 44.

The stop 44 has two end flanges 52 projecting on either side of the junction arm 50. These end flanges 52 are spaced from the side faces of the cavity 28. As a variant, the end flanges 52 of the stop 44 are connected to the lateral faces of the cavity 28.

The wall 46 similar to that of the first embodiment of FIGS. 2, 3, and 4 may include a part forming the joining arm 50 of the stop 44.

Furthermore, as can be clearly seen in Figures 7 and 8, the retaining spring 40 has a fork-shaped end comprising two legs 53 arranged on either side of the joining arm 50. These legs 53 are obtained by making a notch 54 formed in each end portion 48 of the spring 40.

According to one embodiment, the rotor body 21 has two stops 44 per cavity 28, a stop 44 being positioned at each of the axial ends of the rotor body 21. Thus, before inserting the magnet (s) 33 inside a cavity 28, the legs 53 of each end portion 48 of a spring 40 are arranged on either side of a corresponding joining arm 50. The legs 53 are then held between the flanges 52 of the stop 44 and the bottom face 45 of the cavity 28. The magnet (s) 33 are then inserted into the cavity 28, so that the spring 40 is compressed between the magnets 33 and the wall 46 and exerts by reaction a radial force making it possible to maintain the magnet (s) 33 inside the cavity 28.

Advantageously, the retaining stop 44 is formed by a plurality of sheets 22 of the package 21, for example at least 5 sheets. The rotor 12 then comprises two types of sheets 22 to form the package, a first type of sheets 22 comprising a portion of the stop 44, and a second type of sheets 22 being devoid of stop portion 44.

Alternatively, a different stop 44 may be used at each end of the rotor body 21. The spring 40 then has an end portion 48 in the form of a fork located on either side of a junction arm 50 of a stop 44 and a solid end situated in a space between the stop 44 and the wall 46.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention from which one would not depart by replacing the various elements with any other equivalent.

Furthermore, the various features, variations, and / or embodiments of the present invention can be combined with one another in various combinations, as long as they are not incompatible or mutually exclusive of each other.

Claims (14)

1. Rotating electric machine (10), in particular for a motor vehicle, for example for a motor vehicle air conditioning compressor, comprising: - a stator (11), - a rotor (12) comprising a body (21) provided with cavities (28) and at least one permanent magnet (33) disposed inside a cavity (28), - a spring (40) for holding the permanent magnet (33) positioned inside the cavity (28), characterized in that the rotor body (21) comprises at least one retaining stop (44) arranged to hold an end portion (48) of the retaining spring (40), the retaining stop (44) being disposed between a bottom face (45) of the cavity (28) and the magnet (33), - The end portion (48) of the retaining spring (40) being disposed between the bottom of the cavity (28) and the retaining stop (44). 2. Rotating electric machine according to claim 1, characterized in that the holding stop (44) has two end edges, each end edge being connected to a lateral face of the cavity (28). 3. Rotating electric machine according to claim 1, characterized in that the retaining stop (44) comprises a joining arm (50), said joining arm (50) being connected on the one hand to the bottom face (45 ) of the cavity (28) and on the other hand to the retaining stop (44). 4. Rotating electric machine according to claim 3, characterized in that the holding stop (44) comprises two end flanges (52) projecting on either side of the junction arm (50). 5. Rotating electric machine according to claim 4, characterized in that the retaining spring (40) has an end portion (48) in the form of a fork comprising two legs (53) arranged on either side of the arm of junction (50). 6. rotary electric machine according to any one of claims 1 to 5, characterized in that the rotor body (21) comprises at least one wall (46) extending axially along at least a portion of the face bottom (45) of the cavity (28). 7. rotary electric machine according to claim 6, characterized in that the wall (46) extends along substantially the entire height of the cavity (28). 8. rotary electric machine according to claim 6 or 7, characterized in that the wall (46) extends opposite a corrugated portion (49) of the retaining spring (40), said corrugated portion coming resting against the wall (46). 9. rotary electric machine according to any one of claims 6 to 8, characterized in that an end portion (48) of the retaining spring (40) is disposed between the wall (46) and the retaining stop ( 44). 10. Rotating electric machine according to claims 3 and 6, characterized in that the wall (46) has a part forming the junction arm (50) of the retaining stop (44). 11. Rotating electric machine according to any one of claims 1 to 10, characterized in that the rotor body (21) is formed by a pack of sheets (22) constituted by a stack of ferromagnetic sheets (22). 12. Rotating electric machine according to claim 11, characterized in that the holding stop (44) is formed by a plurality of sheets (22) of the sheet pack. 13. rotary electric machine according to claim 11 or 12, characterized in that the rotor body (21) comprises two types of sheets (22) to form the sheet pack, a first type of sheet (22) comprising a portion of the retaining stop (44), a second type of sheet (22) being devoid of portion of the retaining stop (44). 14. Rotating electric machine according to any one of claims 1 to 13, characterized in that the holding stop (44) extends substantially in a plane parallel to a face of the permanent magnet (33) against which comes support the retaining spring (40). 1/4