Rotor for a rotating electrical machine

Abstract

The present invention provides a rotor for a rotating electrical machine comprising a body with an X-axis of rotation in which magnets are inserted, a balancing washer mounted on the body and extending transversely to the X-axis of rotation, a fan comprising a plate having an edge and blades extending from the plate, the fan being fixed to the balancing washer, the balancing washer being axially positioned between the body and the fan, characterized in that at least a portion of the edge of the fan plate is assembled with a lateral edge of a recess in the balancing washer by form interlocking. Figure for the abstract: Fig. 6

Description

Title of the invention: Rotor for a rotating electrical machine

[0001] The invention relates in particular to a rotor for a rotating electrical machine.

[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 reversibly, 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 thermal engine of the vehicle such as a motor vehicle.

[0003] A rotating electrical machine comprises a rotor that is mobile and rotates about an axis X and a fixed stator, mounted in a casing. In alternator mode, when the rotor is rotating, it induces a magnetic field in the stator which transforms it into electric current in order to supply the electrical consumers of the vehicle and recharge the battery. In motor mode, the stator is electrically powered and induces a magnetic field driving the rotor into rotation, for example to start the heat engine.

[0004] The rotor may advantageously comprise a body in which magnets are inserted and a metal balancing washer mounted on the body allowing the machine to be balanced by extrusion of material after its assembly.

[0005] An air-cooled machine also includes fan blades inside the housing. Openings in the housing allow ambient air to circulate between the inside and outside of the machine under the effect of the blades. Machines are known in which the balancing washer is provided with fan blades. Such fan blades help to cool the electronic components of the machine. The blades, for example, molded with the metal washer, have relatively simple geometries, which from a thermal point of view does not optimally promote cooling. In addition, several operations in the rotor manufacturing process require the use of the flat surface of the balancing washer as a support or counter-support. The fan blades on the surface of the balancing washer reduce and sometimes make these support surfaces inaccessible.

[0007] The present invention makes it possible to overcome these drawbacks.

[0008] To this end, the present invention therefore relates to a rotor for a rotating electrical machine comprising a body with an axis of rotation X in which magnets are inserted, a balancing washer mounted on the body and extending transversely to the axis of rotation X, a fan comprising a plate provided with an edge and blades extending from the plate, the fan being fixed to the balance washer, the balance washer being axially between the body and the fan, characterized in that at least a portion of the edge of the fan plate is assembled with a side edge of a recess of the balance washer by form locking.

[0009] A form-locking assembly is an assembly by which two shapes are held attached together solely by virtue of their respective shapes.

[0010] The invention therefore protects a solution for assembling an additional fan on the metal washer. Such an assembly solution is simple. The form locking ensures effective retention of the fan on the washer, particularly when the machine is rotating at high speed. Such a recess dug into the non-magnetic balancing washer does not modify the magnetic properties of the machine.

[0011] It is thus possible to mount on the washer a fan, for example molded, with blades of more thermally efficient geometry. The flat surface of the balancing washer can be used as a support or counter-support during the manufacture of the rotor before assembly of the fan. This makes assembly easier and improves cooling.

[0012] The edge portion of the plate may be made of elastically deformable polymer material, the edge of the plate being assembled by snap-fastening with the lateral edge of the recess of the balancing washer.

[0013] The edge portion of the fan may comprise a draft, the side edge of the recess comprising a counter-draft, the draft cooperating with the counter-draft.

[0014] The balancing washer may comprise a periphery surrounding the recess, an axially upper face of the fan plate and the periphery of the recess being in the same plane.

[0015] At least one blade may extend radially beyond the edge of the tray.

[0016] At least one blade of the fan may have a helical or centrifugal shape.

[0017] The edge of the fan tray may include at least one notch, the edge lateral of the recess comprising at least one stud mounted in the notch.

[0018] The notch may have either a square section or a cylindrical section in the plane of the fan plate.

[0019] The present invention also relates to a rotating electrical machine. The rotating electrical machine can, advantageously, form an alternator, an alternator-starter, a reversible machine or an electric motor.

[0020] The present invention may be better understood by reading the detailed description which follows, non-limiting examples of implementation of the invention and by examining the attached drawings.

[0021] [Fig.l] represents, schematically and partially, a sectional view of a rotating electrical machine according to the invention.

[0022] [Fig.2] is an exploded view of the rotor according to the invention.

[0023] [Fig.3] schematically and partially represents the balancing washer.

[0024] [Fig.4] schematically and partially represents the fan.

[0025] [Fig.5] illustrates the assembly of the fan on the rotor.

[0026] [Fig.6] is a top view of the fan fixed on the balancing washer as well as two sectional views according to two different planes containing the axis of this assembly.

[0027] [Fig.7] illustrates the snap-fit ​​of the fan edge with the side edge of the balancing washer recess.

[0028] [Fig.8a] illustrates the side edge of the recess in another embodiment and [Fig.8b] illustrates the snap-fitting of the fan edge into the recess in this embodiment.

[0029] [Fig.9a] illustrates a centrifugal fan and [Fig.9b] illustrates a helical fan.

[0030] 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. Furthermore, the exemplary embodiments which are described below are in no way limiting. In particular, it will be possible to imagine variants of the invention comprising only a selection of characteristics described below isolated from the other characteristics described. In particular, all the variants and all the embodiments described can be combined with each other if nothing prevents this combination from a technical point of view.

[0031] In the following description the term "axially" will designate the direction of the X axis, the term "radially" will designate one of the directions extending from the X axis in a plane perpendicular to the X axis and the term "angularly" will designate one of the directions around the X axis in the plane mentioned previously. The X axis is oriented from the inside of the machine towards the fan described.

[0032] In the remainder of the description, the elements will be described mounted together around the X axis. Thus, the terms “axially upper” and “axially lower” will designate the relative positions along the direction of the X axis. The terms “radially inner” and “radially outer” will designate the relative positions in a plane transverse to the axis along a radius of the machine.

[0033] [Fig.l] represents a partial schematic sectional view of a rotating electrical machine 1 having an axis of rotation X. The rotating electrical machine 1 comprises a stator 2 and a rotor 3 in a casing 32. The casing comprises for example a first bearing 5, a second bearing 6 and a tubular spacer 7. The tubular spacer 7 is for example sandwiched between the first bearing 5 and the second bearing 6, for example by means of tie rods not shown between the first bearing 5 and the second bearing 6. The stator is fixed inside the casing 32, for example mounted tightly in the tubular spacer 7.

[0034] The stator 2 comprises a stator body 9 and a winding 8. The stator body 9 comprises, for example, a stack of magnetic sheets. For example, the winding 8 comprises electrical conductors, an active part of which passes through notches formed in the body 9 and a connection part or bun 10 is formed outside the notches. The winding 8 is, for example, a hairpin-type winding.

[0035] The rotor 3 comprises a shaft 4 with an axis of rotation X. The shaft is guided in rotation by a first bearing 11 mounted in the first bearing 5 and a second bearing 12 mounted in the second bearing 6. A drive element 13, for example a pulley or a gear, is fixed to the shaft 4.

[0036] The rotor 3 illustrated in exploded view in [Fig.2] also comprises, in the direction of the X axis:

[0037] - a body 15 mounted on the shaft 4 and comprising cavities 24, the body having a first end 33 and a second end 34, opposite the first end, in the direction of the axis of rotation X,

[0038] - magnets 23 received in the cavities 24,

[0039] - a first balancing washer 16 mounted on the body of the rotor at its first axial end 33 and extending transversely to the X axis of rotation of the machine.

[0040] - a fan 20 fixed axially on the balancing washer 16.

[0041] The rotor may optionally include a second balancing washer preventing the magnets from exiting through the second end 34, this second washer being able to carry a second fan. The following description can easily be transposed to this second washer and to this second fan.

[0042] The balancing washer 16 makes it possible to hold the magnets 23 in the cavities 24. The balancing washer 16 comprises a first side 160a and a second side 160b axially opposite the first side 160a, the second side 160b being directly opposite the axial end of the rotor body. The balancing washer is for example made of machined aluminum.

[0043] The balancing washer 16 illustrated in [Fig. 3] advantageously has an annular shape, extending between an inner diameter around the shaft and an outer diameter which is advantageously substantially the same as the diameter of the body 15.

[0044] The balancing washer according to the invention comprises a recess 16a advantageously hollowed out so as to be radially central in the washer 16. The balancing washer thus comprises radially from the inside to the outside, the recess 16a surrounded by a periphery 16b. The balancing washer therefore has a thickness su greater at the periphery than at the recess 16a. The difference in thickness is the depth of the recess PL The recess comprises a lateral edge 161 and a bottom 162. The balancing washer therefore has a notch at the edge 161.

[0045] The bottom 162 advantageously comprises ventilation holes 163 adapted to allow the circulation of air through the balancing washer towards the body 15. These holes are advantageously open in a central annular portion of the bottom 162b, as illustrated in [Fig.3].

[0046] The bottom 162 also comprises counterbores 164 allowing the insertion of elements for fixing the washer 16 to the body of the rotor 15. These counterbores 164 are advantageously arranged in an outer annular portion 162a of the bottom, this annular portion 162a being radially outer to the central annular portion 162b.

[0047] The fan illustrated in [Fig.4] comprises blades 22 capable of moving a fluid, in particular air, from a first radially inner position to a second radially outer position.

[0048] The fan 20 comprises a plate 21 from which the blades 22 extend. The blades 22 extend from an upper face 21a of the plate. The plate 21 also comprises a lower face 21b, the two faces being connected by an edge 21c.

[0049] The fan 20 is mounted axially on the balancing washer 16 on the first side of the washer 160a by inserting at least a portion of the thickness of the plate 21 of the fan into the recess 16a. The lower face of the plate 21b is directly opposite the bottom 162 of the washer, and possibly in contact.

[0050] For reasons of simplification, in the remainder of the description it will be considered that the fan and the recess are substantially circular and that the shape given to their respective edges is the same over the entire circumference of the machine. This does not detract from the general character of the invention as claimed.

[0051] [Fig.5] illustrates the machine for which the fan is fixed to the balancing washer.

[0052] The plate 21 of the fan advantageously has an annular shape extending between the edge 21c and an inner periphery 21d. Thus, when the fan 20 is wedged in the recess of the balancing washer, the fan 20 advantageously does not cover the openwork central annular portion 162b.

[0053] [Fig.6] illustrates a first method of snap-fit ​​assembly of the edge 21c and the lateral edge 161. Snap-fitting means that in a plane containing the axis, at least one radius of the edge of the plate 21c in a plane perpendicular to the axis is greater than the smallest radius of the lateral edge of the recess 161 in another plane perpendicular to the axis.

[0054] The edge of the fan is therefore made of elastically deformable material.

[0055] The edge of the fan 21c comprises a taper, i.e., a linear slope is given to the edge of the fan. In other words, the diameter of the plate 21 decreases continuously along the direction of the X axis of the machine. For example, the edge extends along a direction that forms an angle of between 0 and 30 degrees with the X axis of the machine. A section in a plane containing the X axis of the machine has a straight shape as illustrated in [Fig.7]. The radial difference between the diameter of the plate on the upper face 21a and the diameter of the plate on the lower face 21b is a length L in a radial direction relative to the X axis.

[0056] The lateral edge of the recess 161 comprises an undercut such that along the direction of the X axis, the diameter of the periphery 16b of the recess 16a increases. In particular, the recess 16a has an inlet diameter taken at the upper axial end of the edge 161 and a bottom diameter taken at the bottom 162, the bottom diameter being larger than the inlet diameter.

[0057] For example, the lateral edge 161 extends in a direction which forms an angle between -30 and 0 degrees with the X axis of the machine, therefore with a slope opposite to the edge of the plate 21c. A section in a plane containing the X axis of the machine has a straight shape with a slope reversed relative to the edge of the fan as illustrated in [Fig.7].

[0058] In this embodiment, the case where the thickness of the plate E2 is substantially the same as the depth of the recess PL will be described here. The slope is given by the ratio between the thickness of the plate E2 and the length L. The thickness of the plate E2 will typically be between 2 mm and 6 mm. The length L may typically be between 1 mm and 4 mm.

[0059] The diameter of the fan plate at the lower face 21b is greater than the inlet diameter of the recess 16a, the difference between these diameters being of the order of the length L. The edge of the plate is therefore deformed to be inserted into the recess. After insertion, the edge of the plate 21c substantially resumes its initial slope to cooperate with the undercut of the lateral edge 161. Such an assembly is therefore axially locked by the shape cooperation between the undercut and the undercut.

[0060] In this embodiment, the thickness E2 of the plate and the depth PI of the recess being the same, the upper face of the fan plate and the periphery of the recess are in the same plane perpendicular to the axis. In the absence of a gap, the air flow circulated by the fan is thus improved.

[0061] The blades 22 advantageously protrude radially from the plate 21 as illustrated in [Fig. 5] and extend axially above the periphery 16b of the recess, typically up to the outside diameter of the washer, with an accuracy of 0.2 mm. close.

[0062] The perimeter of the recess advantageously remains available as a support surface, for example before assembly of the fan.

[0063] Figures 8a, 8b illustrate a second embodiment in which the lateral edge of the recess 161 has a shoulder 161a extending from the lateral edge to form a stop. The shoulder 161a extends substantially transversely, relative to the axis X of the machine, over the entire circumference of the edge 161. The shoulder defines an opening whose diameter is less than the largest diameter of the plate.

[0064] For example, the shoulder illustrated in [Fig.8a] extends over a height Hl, in an axial direction relative to the axis X, of at least 30% of the depth PI of the recess. Still for example, the shoulder extends over a length Ll, in a radial direction relative to the axis X, between 0.5% and 3% of the maximum diameter of the recess taken axially between the bottom 162 and the shoulder.

[0065] A section of the recess in a plane containing the axis of the machine extends between a larger diameter and a smaller diameter whose difference is the length LL

[0066] In a section plane containing the X axis, the edge of the fan illustrated in [Fig.8b] comprises at least one portion extending radially beyond the diameter of the opening. The fan plate has a thickness E2. The edge of the fan comprises for example a first portion over a first height H2 over which the diameter of the fan is less than the diameter of the opening of the recess and a second portion over a height E2-H2 over which the diameter of the fan is greater than the diameter of the opening. The difference between the diameters of the first portion and the second portion is a radial length L2 which is less than LL

[0067] The edge of the fan made of elastically deformable material is deformed to be inserted into the recess. After insertion, the second portion returns to its initial shape, the fan being held in the recess by the fact that the second portion is in axial abutment on the shoulder.

[0068] These two embodiments are given by way of example and do not limit the general subject of the invention. All of the characteristics and those which follow may be taken in isolation or in combination.

[0069] The fan is advantageously made entirely of elastically deformable polymer material. The deformable polymer used may optionally contain fibers, typically long fibers for mechanical strength, for example with a content of 30%. The weight of the machine is reduced by the use of such a fan. The fan is for example obtained by molding. The blades 22 are formed in one piece with the plate 21.

[0070] The manufacturing method requires in particular providing a notch 210 on the edge of the fan plate axially opposite each blade 22 to be demolded. Such notches are useful for allowing axial demolding of the fan.

[0071] These notches may in particular have a square section in the plane of the fan plate. Alternatively, such a notch may have a cylindrical section.

[0072] These notches can advantageously be used to index the blades of the front fan relative to the blades of the rear fan. For this purpose, the lateral edge of the recess comprises studs 165 mounted in the notches. At least two diametrically opposed notches are necessary to perform this indexing function.

[0073] Molding makes it possible, in particular, to manufacture fans with blades having optimized geometries to improve cooling. [Fig.9a] illustrates a centrifugal fan whose blades are deformed axially and radially. [Fig.9b] illustrates a helical fan whose blades are deformed along a single axis.

Claims

Claims

1. Rotor for a rotating electrical machine comprising: a body (15) with an axis X of rotation in which magnets are inserted, a balancing washer (16) mounted on the body and extending transversely to the axis X of rotation, a fan (20) comprising a plate (21) provided with an edge (21c) and blades (22) extending from the plate, the fan (20) being fixed to the balancing washer (16), the balancing washer being axially between the body (15) and the fan (20), characterized in that at least a portion of the edge of the fan plate (21c) is assembled with a lateral edge (161) of a recess (16a) of the balancing washer by form locking.

2. Rotor according to claim 1 in which the part of the edge of the plate (21c) is made of elastically deformable polymer material, the edge of the plate (21c) being assembled by snap-fastening with the lateral edge of the recess (161) of the balancing washer.

3. A rotor according to claim 2 wherein the fan edge portion (21c) comprises a relief, the side edge of the recess (161) comprising a counter relief, the relief cooperating with the counter relief.

4. A rotor according to any preceding claim wherein the balancing washer (16) comprises a periphery (16b) surrounding the recess (16a), an axially upper face of the fan plate (21a) and the periphery of the recess (16b) being in the same plane.

5. A rotor according to any preceding claim wherein at least one blade (22) extends radially beyond the edge of the plate (21c).

6. Rotor according to any one of the preceding claims in which the fan (20) is obtained by molding.

7. A rotor according to any preceding claim wherein at least one blade of the fan has a helical or centrifugal shape.

8. A rotor according to any preceding claim wherein the edge of the fan tray (21c) comprises at least one notch (210), the side edge of the recess (161) comprises at least

9. a stud (165) mounted in the notch (210). A rotor according to claim 8 wherein the notch (210) has a cross-section

10. square or cylindrical in the plane of the fan plate (21). Rotating electrical machine comprising a rotor according to one of the preceding claims

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