FRONT FLANGE OF A ROTARY ELECTRICAL MACHINE, AND ROTARY ELECTRICAL MACHINE COMPRISING A FLANGE OF THIS TYPE

Abstract

The front flange made of mouldable material of a rotary electrical machine with a pulley (1) for receipt of a belt comprises at least two projecting braces (70) with axial orientation obtained by moulding of its outer periphery, and designed for securing of a support of at least one body, such as a belt tensioning roller, the braces (70) each comprising laterally at least one hollow (71).

Claims

1. Front flange (8) made of mouldable material of a rotary electrical machine (100) with a pulley (1) for receipt of a belt, comprising at least two projecting braces (70) with axial orientation obtained by moulding of its outer periphery, and designed for securing of a support (122) of at least one body, such as a belt tensioning roller (21), said braces (70) each comprising laterally at least one hollow (71), which in particular is provided in the outer lateral wall of the brace (70).

2. Front flange (8) according to claim 1, wherein the hollows (71) are in the form of a cavity which extends along at least 80% of the height of the brace, and for example extends along the entire height of the brace.

3. Front flange (8) according to claim 1, wherein the hollows (71) have a rounded base.

4. Front flange (8) according to claim 1, wherein the braces (70) are in the form of a shaft.

5. Front flange (8) according to claim 1, wherein a free end (72) of each brace (70) comprises a hole, which in particular is tapped, for screwing of the support (122).

6. Front flange (8) according to claim 1, wherein at least one of the braces (70) comprises two hollows (71).

7. Front flange (8) according to claim 1, wherein three or four braces (70) are provided, each equipped with at least two hollows (71).

8. Front flange (8) according to claim 1, wherein the braces are distributed circumferentially in pairs according to an angle of between 30° and 100°, for example between 45° and 90°.

9. Front flange (8) according to claim 1, wherein at least one of the braces (70) comprises an opening (132) in its outer periphery, implanted in the vicinity of the area of rooting (73) of the brace (70) on the body of the front flange.

10. Front flange (8) according to claim 1, comprising a base (31) which is extended at its outer periphery by a rim (30), wherein the hollows (71) extend axially from the free end (72) of the braces (70) to an area of rooting (74) on the base (31) of the flange (8).

11. Rotary electrical machine (100), in particular for a motor vehicle, comprising a pulley (1) for receipt of a belt, comprising a front flange (8) according to claim 1.

12. Front flange (8) according to claim 2, wherein the hollows (71) have a rounded base.

13. Front flange (8) according to claim 2, wherein the braces (70) are in the form of a shaft.

14. Front flange (8) according to claim 3, wherein the braces (70) are in the form of a shaft.

15. Front flange (8) according to claim 2, wherein a free end (72) of each brace (70) comprises a hole, which in particular is tapped, for screwing of the support (122).

16. Front flange (8) according to claim 3, wherein a free end (72) of each brace (70) comprises a hole, which in particular is tapped, for screwing of the support (122).

17. Front flange (8) according to claim 4, wherein a free end (72) of each brace (70) comprises a hole, which in particular is tapped, for screwing of the support (122).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0063] FIG. 1 is a schematic view in axial cross-section of a rotary electrical machine according to the prior art;

[0064] FIG. 2 is a side view of a rotary electrical machine equipped with a front flange according to the invention;

[0065] FIG. 3 is a partial view in perspective of the pulley and of the front flange in FIG. 2;

[0066] FIG. 4 is a view similar to FIG. 3 without the pulley;

[0067] FIG. 5 is a partial front view of the front flange in FIGS. 2 to 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0068] In the figures, elements which are identical or similar to those in FIG. 1 will be allocated the same reference numbers, and for the sake of simplicity FIGS. 2 to 5 represent only the elements which are necessary for understanding of the invention.

[0069] For the other internal elements of the machine, i.e. rotor shaft, ball bearing, stator, rotor, fans, brush-holder, sensor-holder, inverter, rectifier bridge, as applicable, reference will be made to the prior art and to FIG. 1, in the knowledge that the rotor of the machine can be a rotor with claws, a rotor with projecting poles, or a rotor with permanent magnets, and the stator winding can have concentric coils, as for example in document WO 2007/031679, or an undulating winding as for example in document EP 0 881 742. In FIGS. 2 to 5, the rotary electrical machine 100 is an alternator-starter with internal ventilation of the type in FIG. 1 and that described for example in document WO 01/69762 or document FR A 2 745 444, with an offset electronic casing. This alternator-starter thus comprises a pulley 1 which is integral with the rotor shaft with an axis X-X. The orientations axial, radial, circumferential and transverse will apply hereinafter with reference to the axis X-X which constitutes the axis of rotation of the machine 100, of the rotor and of the stator.

[0070] The housing 6, 8 of the machine 100 comprises at least two parts 6, 8, i.e. a front flange 8 and a rear flange 6 which are connected by tie rods. These flanges 6, 8 have a hollow form, and comprise centrally a receptacle for fitting of a ball bearing for rotation of the rotor shaft (see FIG. 1). It will be appreciated that, in a known manner, the housing of the machine can comprise an intermediate part between the flanges 6, 8 which supports the stator body. In FIG. 2, an orientation from front to rear corresponds to an orientation from left to right, and it can be seen that, like in FIG. 1, at the rear the machine comprises a protective cover with no reference which is integral with the flange 6.

[0071] The flanges 6, 8, which are also described in document WO 02/09371, are made of mouldable material, i.e. of aluminium in this example, and as a variant of plastic material which is preferably reinforced, for example with glass fibres.

[0072] These perforated flanges 6, 8 comprise openings for the air outlet 32 and inlet, for internal circulation of the air by means of a fan/fans integral with the rotor.

[0073] The air outlet openings 32 are mostly formed on the outer periphery of the flange 6, 8, more specifically in an outer peripheral rim, which has a globally cylindrical form and axial orientation, of the flanges 6, 8. The air inlet openings are formed in a base, in this case with globally transverse orientation, which the flanges 6, 8 comprise. The bases are connected on the exterior to the outer peripheral rims. Thus, as far as the front flange 8 adjacent to the pulley 1 is concerned, FIGS. 3 to 5 show at 31 the base, at 33 the air inlet openings, at 32 the air outlet openings, and at 30 the rim. The outlet openings 32 are obtained by removal from the mould, and consequently partly affect the base 31. FIG. 2 shows a securing means in the form of a securing lug 35, which the rim 30 of the front flange 8 comprises as a radial projection. This FIG. 2 also shows a securing lug, with no reference, of the flange 6. As a variant, the securing means are in the form of an ear, or are formed by means of a plate. In this example, the flange 8 also comprises a securing ear which is not shown.

[0074] This rotary electrical machine 100 with a pulley 1 for receipt of a belt is equipped at the front with a support 122 of a device 20 for adjustment of the tension of the belt. As in FIG. 1, the pulley 1 and the belt are of the Poly-V (registered trademark) type, the pulley 1 comprising grooves in order to receive the belt in a complementary manner.

[0075] As a variant, the belt 1 has a trapezoidal form, and the pulley 1 comprises a trapezoidal channel for receipt of the belt.

[0076] The device 20 comprises at least one body in the form of a roller for tensioning of the belt supported by the support 122. The body can be in the form of a dynamic tensioning roller.

[0077] According to one characteristic, the front flange 8 made of mouldable material comprises at least two projecting braces 70 with axial orientation obtained by moulding its outer periphery, and designed for securing a support 122 of at least one body, such as a belt tensioning roller, the said braces each comprising laterally at least one hollow 71.

[0078] Advantageously, at least one of the braces 70 comprises two hollows 71. The braces 70 are obtained partly from the outer periphery of the base 31, and partly from the outer periphery of the rim 30, in the manner described hereinafter. The braces 70 extend axially projecting in the direction opposite the base 31, constituting the front face of the flange 8 adjacent to the pulley 1.

[0079] As a result, the support 122 is distinct from the means 35 for securing the housing 6, 8 on a fixed part, and the porosity of the braces 70 is minimised, which makes the latter more robust. In addition, the size at the front face of the front flange is reduced since the support is distinct from the securing means 35.

[0080] The number of braces 70 depends on the applications and the forces to be withstood.

[0081] In this embodiment, three braces 70 are provided in order to secure the support 122 which is subjected to stress by the device 20. As can be seen in FIG. 5, two braces 70 are implanted circumferentially between two passages (with no reference) of the tie rods for assembly of the flanges 6, 8. In this example, three hollows 71 are provided by braces 70 with axial orientation. The number of hollows 71 can vary from 2 to 4 according to the size of the brace 70.

[0082] As can be seen in FIGS. 3 to 5, the hollows 71 are in the form of a cavity with a shallow depth. These hollows 71 have a length which is long in comparison with their depth.

[0083] The hollows 71 have a rounded base with a radius which is different from the radius of the flanks of the hollow 71 connecting the base of the hollow to the outer periphery of the brace 70. The braces 70 have a globally frusto-conical form for reasons of axial removal from the mould, the angle of the cone being small. Thus, the braces are in the form of a shaft.

[0084] The hollows 71 extend axially from the free end 72 of the braces 70 at the base 31 of the flange 8. FIG. 4 shows at 74 the area of rooting of a brace on the outer periphery of the base 31. This area 74 is affected by the hollows 71. The reference 73 designates the area of rooting of a brace on the outer peripheral rim 30 of the flange 8. At least one of the braces 70 comprises on its outer periphery an opening 132 for discharge of air. This opening 132 is implanted in the vicinity of the area of rooting 73 of the brace 70 on the body of the flange 8. In this example, this opening 132 is implanted in the vicinity of the rim 30.

[0085] Advantageously, each brace 70 has an opening 132. The opening(s) 132 is/are implanted at the air outlets 32, and thus permit good discharge of the air.

[0086] The three braces 70 are distributed circumferentially according to an angle of more than 90° and less than 180°. Thus, the support 122 can have a form of an arc of a circle which extends radially on the exterior of the pulley 1. This support 122 permits the passage of the air through the air inlet openings 33. It will be appreciated that the braces are distributed on the outer periphery of the front face of the front flange 8 adjacent to the pulley 1, which makes it possible to clear a good passage between the support 122 and the pulley 1, without interference.

[0087] The braces 70 extend projecting on at least 25% of the length of the pulley 1.

[0088] The free end 72 of the brace in the form of a shaft is perforated and tapped for screwing of the support 122 of at least one tensioning roller. In this example, the support 122 is the support of the device 20 for adjustment of the tension of the belt comprising two tensioning rollers.

[0089] The adjustment device 20 comprises at least one tensioning roller 21 for adjustment of the tension of the belt, which in this case is implanted globally radially above the pulley 1. This device 20 is adjacent to the pulley 1, and extends projecting axially relative to the front end of the front flange 8. As is known, thanks to the device for adjustment of the tension of the belt, optimum tension of the belt is obtained, sliding of the belt is prevented, and there is filtering of the vibrations which can detract from satisfactory functioning of the rotary electrical machine, in the knowledge that these vibrations can break the securing means, such as ears or lugs or plates which the housing with a front flange has in order to be secured on a fixed part, such as the engine block of a motor vehicle. In this example, the device 20 comprises another tensioning roller which is supported by the support 122. The rollers are connected resiliently by a spring 22 with circumferential action, whilst being arranged laterally on both sides of the pulley 1. One of the rollers can be fixed, whilst being integral with the fixed support 122, whereas the other roller 21 can be displaced circumferentially under the action of the spring 22, whilst being supported by the support 122. Each roller is fitted such as to rotate by means of a pivot supported by an ear 23, preferably with intervention of a ball bearing between the inner periphery of the roller and the outer periphery of the pivot. The spring 22 is globally in the form of an omega, the ends of which are coupled to the ears of the rollers. The pivots, the ears and the rollers each belong to a coaxial part, one of which is constituted by the support 122. The part which supports the roller 21 is wedged in translation by the support 122, and is mobile circumferentially against the spring 22. These parts are thus supported by the support 122, and can be displaced circumferentially against the circumferential force exerted by the spring 22. For this purpose, the support 122 comprises at the front a hub which projects axially for fitting with rotation of the coaxial part comprising the pivot, the ear and the roller 21 belonging to the part which is mobile in rotation relative to the support 122.

[0090] As a variant, the two assemblies, each comprising a roller fitted such as to rotate on a pivot supported by an ear, each belong to a coaxial part which is fitted such as to rotate on the hub of the support 122, and wedged in translation by the said support 122. These parts can each be displaced circumferentially relative to the support 122, against the circumferential force exerted by the spring 22.

[0091] The presence of two rollers is justified by the fact that the rotor shaft is driven when the alternator-starter is functioning in alternator mode, in particular in order to charge the battery of the vehicle and supply its consumers electrically, whereas it drives when it is functioning in electric motor mode, in particular in order to start the engine of the vehicle.

[0092] According to one embodiment, the free end 72 of the braces 70 can have an outer diameter which is globally 20 mm, whereas the bases of the hollows 72 can be implanted on a diameter which is globally 16 mm, thus permitting good retention of the support 122. It will be appreciated that these dimensions depend on the applications and are given by way of indication.

[0093] This support 122 can comprise perforated ears opposite free ends 72 of the braces 70, for passage of securing screws screwed into the tapped holes of the free ends 72. The ears can be hollow and can cap the free ends 72. Good retention of the support 122 is thus provided.

[0094] The movement transmission belt can drive only the rotary electrical machine, via its pulley.

[0095] As a variant, the movement transmission belt can also drive another accessory, such as the compressor of an air conditioning installation. In this case, the thermal engine of the motor vehicle and the accessory each have a pulley for passage of the belt. For further details on the path of the movement transmission belt, reference will be made to FIG. 1 of document DE 102011082764 (EP 2 627 929 B), the two rollers being arranged laterally on both sides of the pulley. As a variant, the accessory with a pulley can be a water pump.

[0096] As a variant, the free end 72 of the brace 70 is in the form of a rivet for securing by riveting of the support 122 of at least one tensioning roller. This solution is easier to implement when, in the aforementioned manner, the front flange is made of plastic material, with the heads of the rivets being deformed by heat in order to provide the riveting. In all cases, the support 122 is perforated locally for passage of the screws for securing on the free ends 72 of the braces 70, or for passage of the rivets of the free ends of the braces 70 rooted on the flange 8.

[0097] The braces 70 and the hollows 71 are advantageously obtained by moulding of the flange 8 made of mouldable material.

[0098] As a variant, the base 31 of the front flange 8 is inclined. In this case, the flange comprises a nose for accommodation of the ball bearing for fitting of the rotor shaft with rotation.

[0099] As a variant, within the context of an alternator. The support 122 supports only one tensioning roller with intervention of a spiral spring, or a rack and pinion device as described in the aforementioned document EP 0 459 894.

[0100] The body which is supported by the support is not necessarily a roller.

[0101] As a variant, the front flange is not perforated, with the housing of the machine comprising a chamber for cooling of the machine for circulation of a heat transfer fluid, such as the cooling liquid of the thermal engine of a motor vehicle.

[0102] In these FIGS. 2 to 5, in addition to its function as a starter and its function of starting and stopping the thermal engine of the vehicle, depending on its power the alternator-starter can provide other functions, in particular in order to prevent the thermal engine from stalling.

[0103] As a variant, the alternator-starter is an alternator starter with integrated electronic components and a mezzanine, as described for example in documents WO 2006/129030 and WO 2004/040738.

[0104] As a variant: [0105] the rotary electrical machine is an electric motor; [0106] the electric motor drives at least one another accessory; [0107] the rotary electrical machine is an electric motor without brushes and is controlled by an inverter as described for example in document EP 0831 580; [0108] the electrical machine is a starter with a belt; [0109] the rotary electrical machine is an alternator with a bridge for rectification of alternating current into direct current, for example of the type described in the aforementioned document WO 02/093717.