FR2648886A1 - PULLEY FOR DRIVING AT LEAST ONE ATTACHMENT, IN PARTICULAR FOR A MOTOR VEHICLE, AND AN ACCESSORY NOSE ASSOCIATED WITH SUCH A PULLEY - Google Patents

Abstract

The present invention relates to a drive pulley of at least one accessory of the type comprising an electromagnetic clutch 5, 3, 23, anti-friction bearing means 31, 36, an annular and hollow support 18 and flanges 17, 14 for receiving a drive means C. According to the invention, the pulley is characterized in that the reel 5 is, by means of a stationary carrying part 6 supporting said reel 5 and suitable for being secured to the nose 24 of the 'accessory, arranged between the clutch plate 23 and the flange 17, closest to the clutch plate 23, and in that the carrier part 6 is interposed axially with clearance between the free end of the support 18 and the part link 21, 22. Application: motor vehicles.

Description

The present invention relates to a drive pulley of at least one

  accessory, particularly for a motor vehicle, of the type comprising an electromagnetic clutch, anti-friction bearing means, for mounting on a nose carried by the accessory, an annular and hollow support, mounted on the outer periphery of said bearing means and bearing annular flanges for receiving a drive means, said electromagnetic clutch comprising a spool and a movable clutch plate rotatably connected to a connecting piece penetrating inside said bearing means, for rotational connection, with a drive shaft of the accessory. It also relates to an accessory nose associated with such a pulley, said nose being mounted on the inner periphery of said

bearing means.

  Such a pulley is described in the document

US-A-3,762,516.

  In this document, the flanges are arranged on a circumference of large diameter because of the presence of locking parts belonging to the support. In addition, the bearing means are arranged at

vicinity of the clutch plate.

  In general, it may be desirable to bring the flanges closer to the bearing means for

  to reduce the phenomena of inertia.

  Similarly, it is preferable to bring the bearing means and the flanges of the accessory closer together.

  to reduce the stresses generated by the door - & - false.

  The present invention aims to overcome these disadvantages and thus to create a pulley with flanges arranged near the bearing means, while having the possibility to move said bearing means of the clutch plate and providing other advantages . According to the invention, a pulley of the type indicated above is characterized in that the coil of the electromagnetic clutch is, via a fixed support piece supporting said coil and adapted to be secured in rotation to the nose of the accessory, arranged between the clutch plate and the flange closest to the clutch plate, and in that said bearing part is interposed axially with play.

  between the end of said support and the connecting piece.

  Thanks to the invention, the flanges can extend in the vicinity of the bearing means, the support of said flanges can be simplified and consist of

a shouldered sleeve.

  Because of the location of the coil, said bearing means can be moved away from the clutch plate so that cantilever phenomena and stresses are reduced. We will appreciate that he

  becomes possible to reduce the number of steps.

  The arrangement according to the present invention makes it possible to arrange the fixed flange to transform it into a secondary pulley causing other accessories because it is possible to transmit a larger torque.

  thanks to the approximation of the flanges of the bearing means.

  It will be appreciated that the axial bulk of the assembly can be reduced. With equal axial dimensions it becomes possible to create a pulley with at least one movable flange, so that said pulley can belong to a variable speed drive and that the accessory

  works in better conditions.

  Thus the performance of the accessory is improved, while having a low-noise pulley, continuously variable speed and smooth, unlike provisions epicyclic gear described for example

in document FR-A-24 14 626.

  We will also appreciate, in relation to these provisions, the reduction of the cantilever and the number

of bearings.

  According to a characteristic of the invention the flange closest to the clutch plate, has a cavity for housing the clutch coil and

of its supporting part.

  The closing of the magnetic field can be carried out very simply, the fixed flange carrying a fixed plate of ferromagnetic material, said plate being interposed axially between the coil, surrounded by a ferromagnetic material envelope, possibly formed in part by a portion fixed platform, and the clutch plate itself in

ferro-magnetic material.

  Advantageously, for a better yield and a gain in weight, the carrier piece is at least partially made of non-magnetic material such as

  plastic material or aluminum.

  Of course, it may be made of magnetic material or, alternatively, be of non-magnetic material

  magnetic than at the coil.

  According to another characteristic, the connecting piece may have a hollow shaft shouldered, so that it becomes possible to interpose between said shoulder and the drive shaft of the accessory a shim to adjust the air gap. the electromagnetic clutch. According to another feature, the nose of the accessory is dug for passage of the coil supply wires, so that a good

  protection of the wires is naturally assured.

  Thanks to this arrangement, the presence of a bracket, passing between the strands of the belt, and of

  rolling means is no longer necessary.

  The following description illustrates the invention

  with reference to the accompanying drawings in which: - Figure 1 is an axial sectional view of a pulley according to the invention; FIG. 2 is a view similar to FIG.

  for another embodiment.

  In the present invention the driven accessory is a compressor for an installation of

air conditioning.

  Of course it could be an air compressor for supercharging the engine or any other accessory. This accessory has a fixed body 1 and a drive shaft E. The pulley comprises an electromagnetic clutch with a coil 5, a clutch plate 23 axially movable. The accessory carries a fixed nose 24, here in the form of an annular sleeve attached by force fitting on a hollow sleeve 1 'protruding from

  to the body 1 secured to the vehicle after assembly.

  Anti-friction bearing means 31, here in the form of a double-row ball bearing, are fitted, by their inner periphery, on the nose 24 stepped for this purpose. This bearing 31, according to a characteristic of the invention, is arranged in the vicinity of the free end of the sleeve 1 'and carries an annular and hollow support 18, attached to the outer periphery

said bearing.

  The support 18 here consists of a stepped sleeve,

  hereinafter hub, for bearing on the bearing 31.

  This support 18 carries two flanges 17 and 14 for receiving a belt C. The clutch plate 23, said pressure plate, is integral in rotation with a connecting piece 21,22 penetrating inside the bearing 31 and the nose 24 for connection in rotation with the drive shaft E. The piece 21,22 is mounted at the end of the

  pulley, at its end opposite to the body 1.

  In a manner known per se, the plate 23 is mounted axially movable by means of tangential tongues 20. Here the connecting piece comprises a hollow tubular hub 22 at the end of which is fixed, by crimping, a flange 21 carrying the tangential tongues 20 These are fixed here to the pressure plate 23 and to the flange 21 by screws 35 with domed head. According to the invention the pulley is characterized in that the coil 5 is, via a fixed support part 6 supporting said coil 5 and adapted to be secured to the nose 24 of the accessory, arranged between the plate of clutch 23 and the flange 17, the closest clutch plate 23, and in that the carrier part 6 is interposed axially clearance between the free end of the support 18 and the liaision piece

21.22.

  According to another characteristic of the invention the flange 17, the closest to the pressure plate 23, has a cavity for accommodating at least part of the coil 5 and the carrier part 6. Here the coil 5 and

  the piece 6 are housed in said cavity ..

  This bearing part 6 is fixed and is interposed axially with clearance between the free end of the support 18 and

the flange 21.

  It will be noted that said free end of the support

  18 is the furthest away from the accessory.

  Here the piece 6 is made of non-magnetic material and generally has the shape of an inverted S, the base of said S consisting of an annular return of axial orientation force-fitted on the nose 24 and cooperating with the edge of the inner ring of the 31 bearing, the other end is supported against a shoulder of the nose 24 formed through a change in diameter. As can be seen in FIG. 1, the bearing 31 is fitted on the reduced-diameter portion of the nose 24, the larger diameter portion of which is itself force-fitted onto the sleeve 1 ', supported for this purpose, by the accessory

for solidarity with it.

  The outer periphery of the carrier piece 6 is fixed to a casing 5 ', made of ferro-magnetic material surrounding the coil 5, with screws, one of which is visible in the lower part of the figure. As shown in this figure, to do this, the part 6 is provided with a scope 60 for receiving the envelope 5'emmanchée

on said span 60.

  The pulley is here a driven pulley of a variator. As is known, such a variator comprises a driving pulley, a driven pulley, and a belt C looped endlessly on one and the other of these pulleys. Each pulley of this variator comprises a hub (here the support 18), and two annular flanges frustoconical shape (here the flanges 17 and 14), at least one of which (the flange 14) is mounted axially movable under the

  control of elastic return means 13.

  The movable flange of the driven pulley is axially movable between two extreme configurations, one advanced in fine lines in Figure 1, the other recessed, being understood that in retracted configuration the transmission ratio is maximum, while in advanced configuration the transmission ratio

decreases.

  Of course, when the movable flange of the driven pulley is in advanced configuration, the movable flange of the driving pulley is in remote configuration

and vice versa.

  The support 18, of cylindrical shape, carries at its free end, the farthest from the shaft E, the

  fixed flange 17 secured to said support by crimping.

  Here, this fixed flange 17 is of the type described in the French patent application FR-88 12 170. It has a dropped radial edge directed towards the axis of the shaft E and the crimping pulley with the hub 18, a central portion of axial orientation connecting said fallen edge to the frustoconical portion of the fixed flange. It has at its outer periphery an axial flange 16 in which is formed a pulley

  notched secondary as shown in Figure 1.

  This flange thus has an open cavity defined by the flange 16, its frustoconical portion and the

axial return.

  It is in this cavity that the coil 5 is housed with its envelope 5 'and the carrier part 6, the latter by its S-shaped configuration bypassing the axial return of the mobile flange and the support 18, to penetrate to inside the support 18 and come to fix

on the nose 24.

  Note that a small gap exists between

the envelope 5 'and the flange 16.

  According to a characteristic of the invention, the carrier part 6 is made of non-magnetic material, while the casing 5 ', section U-shaped, is made of ferro-magnetic material. Thanks to this, the efficiency of the clutch is improved and a weight saving is obtained, said piece 6 being able to be made of plastic or

aluminum.

  A fixed plate 3, made of ferro-magnetic material, is fixed on the free end of the flange 16 in favor of

screw 2.

  This plate 3, said reaction plate, of annular shape, has in section an axial portion coming into contact with the inner periphery of the flange 16 for attachment thereto by the screws 2, said part being extended by an orientation part overall radial directed towards the axis of the assembly, being connected, at its inner periphery, to an axially oriented portion interposed radially between the carrier part 6

and the envelope 5 '.

  The radial orientation part of the part 3 is intended to cooperate with the plate 23, with the possible interposition of friction linings, with definition of an air gap, when the coil 5 is not powered. Thus the plate 3 is interposed axially between the casing 5 'with its coil 5 and the pressure plate 23. Of course, the plate 3 can belong to the casing 5' by means of an extension of its axially oriented portion arranged below the coil 5, said part forming the inner part of the casing ', the lower part of the casing 5' of FIG. 1

being deleted.

  Advantageously, the fixed flange 17 is in

  ferro-magnetic material, for example ferro-cast iron

magnetic or mild steel.

  As will be understood, thanks to the piece 6 of non-magnetic material, the looping of the magnetic field is easily done by the rim 16, the part 3, the plate 23 and the envelope 5 '; the parts 3,23,5 'being by

example in mild steel.

  As a variant not shown, the span 60 may extend over the entire portion of the axial return of the part 6 interposed radially between the return of the flange 17 and the envelope 5 '. In this case a piece of ferromagnetic material can be fitted on said bearing surface 60, the casing 5 'being mounted on said piece, which extends opposite the plate 3 then without axial return to

its inner periphery.

  Of course, thanks to the piece 6 the envelope 5 '

  can come closer to the flange 16 of the pulley.

  According to a characteristic the setting of

  the air gap is made using adjustment rings 28.

  These shims are interposed between a shoulder of the shaft E and a shoulder that internally has the hub 22. Said shoulder of the hub 22 is made in favor of a wall 51 traversed by the threaded end

  of the tree E being turned towards the body 1.

  As can be seen in FIG. 1, the connection in rotation between the hub 22 and the shaft E is achieved by means of keys, the axial connection is made by means of a nut 30 with the interposition of a washer 29. , for example a spring washer, between the nut 30 and

the wall 51.

  According to a characteristic of the invention, the supply of the coil 5 is carried out by means of wires F fitted into grooves made respectively at the outer periphery of the nose 24 and in the part 6, on the side thereof facing towards the flange 21. To avoid contact of the son with the rotating parts of the pulley, including the support 18, there is provided a protective sheath 25 bypassing the end of the support 18 adjacent to the accessory, said sheath being force-fitted on the nose 24 fixed. On the side of the part 6, for covering the groove thereof, it is provided, opposite the flange 21, a cup 26 pressed against the part 6 with a circlip 33 engaged in a groove that has the nose 24 at its free end. The casing 5 'is hollowed out for the passage of the supply wires F. It will also be noted the presence of a circlip 32 for axially locking the bearing 31 between said circlip 32

  and the shoulder of the support 18 facing the sleeve 1 '.

  The mobile flange 14, which is also frustoconical in shape, has a bushing which is slidably engaged by means of bearings 15 on

  the outer periphery of the support 18.

  As described in the aforementioned document 88 12 180, this bushing is surrounded by the axial return of the fixed flange 17, which allows a compact arrangement, the flange 14 being movable under the control of elastic return means 13, comprising at least one annular piece 11 such as a diaphragm having, on the one hand, a peripheral portion in the form of a Belleville washer, which is in axial support swinging against the mobile flange 14, and, on the other hand, a central portion divided into radial fingers by slots, which is in axial support tilting against a support piece 9 fixed relative to the support 18 being fixed thereto, here by crimping. In Figure 1 the elastic means 13 are constituted by two diaphragms 10,11 arranged parallel to one another and separated from one another by a coating 8 of elastic material. This coating 8 extends radially beyond the diaphragms 10, 11, to form, outwardly, a bead of elastic material embedded in a recess in the movable flange 14 by means of an axial return 14 'of the in order to constitute an axial tilting support for the diaphragms 10, 11 and to secure them with the

mobile flange 14.

  The elastic means 13 also comprise a counterweight 12 parallel to the diaphragm 10, 11 and separated from

these by the coating 8.

  For embedding the bead of the coating 8, the flange 14 has, thanks to its axial return 14 ', undulations, of shape complementary to the undulations that has said bead opposite said

flange 14 '.

  Internally at the inner periphery of the diaphragms 10, 11, the coating 8 is extended by an axial spacer secured to the support piece 9, by

  example by bonding or vulcanization in situ.

  As can be seen in FIG. 1, note the presence of a seal 19, for example an Oring, for sliding the sleeve of the flange 14 relative to the

fixed flange 17.

  A stop washer 27 is interposed between the

  inner ring of the bearing 31 and the shoulder of the nose 24.

  When the coil is not energized, the plate 23 is at a distance from the part 3, whereas when the coil is energized, said plate 23 is attracted by the coil for contact with the part 3 and rotational connection of the flange 17 with the connecting piece 21 to 22 and the drive shaft E. As shown in this figure, the belt C in the retracted position of the movable flanges is close to the axis of the pulley, while in the advanced position of the flanges

  mobile, it occupies a position remote from the axis.

  FIG. 2 is a view similar to FIG. 1, with the modification of the anti-friction bearing means, these having a second bearing 36 of reduced diameter interposed axially between the part 6 and the bearing 31 and radially between the nose 24 and the support 18. As is evident from the

  description and drawings, the layout according to

  The present invention is compact both axially and radially, the configuration of the flanges 17, 14 and the arrangement of the elastic return means 13 to

  neighborhood of the accessory promotes such compactness.

  The accessory works in good conditions thanks to the flange 14,17, while the location of the coil 5 in the cavity of the fixed flange 17 allows to bring the anti-friction bearing means 31 of the accessory. Here, as shown in the figures, the axis of the belt C extends axially between the accessory and the axis of the ball bearing 31.

  In addition, the layout is not very noisy.

  As will be understood, it is possible to mount the equipped pulley on the nose 24, or to mount the

  pulley with the nose 24 on the part 1 'of the accessory.

  Alternatively the nose 24 can be in one piece

with the accessory 1.

  Of course, the present invention is not

  limited to the embodiments described.

  In particular, the elastic return means 13 may comprise only a diaphragm pivotally mounted using driving blocks or spacers, as described in GB-A2109490. The provisions of the abovementioned document FR-88 12 180 are also applicable, particularly in

  which concerns the mounting of the elastic means.

  Of course, the two flanges can be fixed and the belt be notched. The configuration of the pulley may be of the type described in the aforementioned GB-A-2109490. In this case the coil 5 with its carrier part 6, is housed only partially

  in the cavity defined by the fixed flange.

  Similarly, while in this description

  a belt is used as drive means, when the flanges are fixed the transmission can be done via a

chain or any other means.

  Instead of a ball bearing 31,36, it is possible to use as a means of anti-friction bearing, a plastic bearing with a low coefficient of friction.

or a lubricated bearing.

  The presence of the secondary pulley is not essential, and the flange 17 may be devoid of axial flange 16, the plate 3 then having an axial extension for its attachment to the periphery

outer flange 17.

  Finally, the piece 6 can be made of magnetic material, it can be made of non-magnetic material

  only at the level of the envelope 5 '.

Claims (8)

  1) Drive pulley of at least one accessory, particularly for a motor vehicle, of the type comprising an electromagnetic clutch (5,3,23), anti-friction bearing means (31,36), for mounting on a nose (24) carried by the accessory, a support (18) annular and hollow, mounted on the outer periphery of said bearing means (31) and carrying annular flanges (14,17) for receiving a drive means, said electromagnetic clutch comprising a coil (5) and a clutch plate (23) movable, rotatably connected to a connecting piece (21, 22) penetrating inside said bearing means (31, 36), for connection in rotation with a drive shaft (E) of the accessory, characterized in that the coil (5) of the electromagnetic clutch is, via a fixed support part (6) supporting said coil ( 5) and adapted to be secured to the nose (24) of the accessory, arranged between said clutch plate (23) and the flange (17) closest to the clutch plate (23), and in that said carrier piece (6) is interposed axially with clearance between the end of said support (18) and. the connecting piece (21,22).   2) pulley according to claim 1, characterized in that the flange (17) closest to the clutch plate (23) has a cavity for accommodating at least part of said coil (5) and its part carrier (6) associated.   3) Pulley according to claim 1 or 2, characterized in that the fixed flange (17) carries a fixed plate (3) of ferromagnetic material, said plate (3) being interposed axially between the coil (5), surrounded by an envelope (5 ') of ferromagnetic material, and the clutch plate (23) itself made of ferromagnetic material.   4) Pulley according to any one of   preceding claims, characterized in that the   connecting piece (21,22 ') has a stepped hollow shaft (22) for interposing between said shoulder and the drive shaft (E) a shim (28) for adjusting   the air gap of the electromagnetic clutch. Pulley according to any one of   preceding claims, characterized in that   the supply of the coil (5) of the electromagnetic clutch is carried out by means of wires (F) fitted into a groove made in the bearing part (6) on the side thereof facing towards the flange (21) which comprises the connecting piece (21,22) for   rotational connection with the clutch plate (23).   6) Pulley according to claim 5, characterized in that the groove of the carrier part (6) is covered by a cup (26).   7) Pulley according to any one of   preceding claims, characterized in that the   flange (17) closest to the clutch plate (23) is a fixed flange secured to the support (18), said flange (17) having at its outer periphery an axial flange (16) for delimiting the housing cavity of the coil (5).   8) Pulley according to claim 7, characterized in that the other flange (14) of the pulley is movable under the control of elastic return means (13), comprising at least one annular piece (10,11) such as a diaphragm , which is in axial support tilting against the movable flange (14) and against a support piece (9) relative to the support (18), said part being fixed to said support (18).   9) Pulley according to claim 8, characterized in that the movable flange (14) centrally has a sleeve slidably engaged on the outer periphery of the support (18) and in that said sleeve penetrates inside an axial return that presents the fixed flange (17), said axial return defining the housing cavity of the coil (5) of the electromagnetic clutch. ) Accessory associated with a pulley according to one   any of the preceding claims, having a   nose (24), characterized in that said nose (24) has at its outer periphery a groove for passage of the supply son (F), and in that it carries a protective sheath (25) interposed between said nose (24) and the support (18) of the pulley.