FR2766894A1 - HYDROKINETIC COUPLING APPARATUS WITH TAB DRIVE PART, PARTICULARLY FOR MOTOR VEHICLE - Google Patents

Abstract

The apparatus comprises a generally transversely oriented wall (2) carrying for attachment a guide ring (6), a piston (9) movably mounted along the guide ring (6) while being connected in rotation to the wall transverse (2) with axial mobility by means of resilient tongues (40) integral with a drive part (44) having an internal portion (444) extending radially below the piston and connected in rotation to the one of the guide ring (6) - transverse wall (2) elements, said internal portion being adjacent to one of the transverse wall (2) - guide ring (6) elements. Automotive vehicle application.

Description

The present invention relates to coupling devices

  hydrokinetic, in particular for a motor vehicle, as described for example in

WO-A-94/07058.

  In this document, the device has a generally transverse orientation wall capable of being linked in rotation to a driving shaft and carrying a fixing

  centrally a guide ring, forming a hub.

  A piston is mounted axially movable with sealing along the guide ring and defines with the transverse wall and the guide ring a variable volume control chamber delimited externally by a disc and friction linings 10 adapted to be clamped respectively between the piston and the disc and

  between the disc and the transverse wall.

  Each friction lining is integral with one of the disc-piston-transverse wall elements respectively, between which it is intended to be clamped. It has already been proposed in document FR-A-2 634 849 to link the piston in rotation to said transversely fixed transverse wall by means of elastic tongues of tangential orientation fixed to a drive part arranged in

the variable volume chamber.

  In practice, this drive part is in the form of a disk movable axially with respect to the guide ring carried centrally by said transverse wall and passing through it to form a centering device. This is achieved by means of grooves made on the guide ring and allowing axial movement of the piston - drive part assembly. The rotational connection of the disc to the ring is made by leaving an axial clearance between the wall and the disc. This connection is made on a diameter slightly greater than the diameter of the internal bore of the piston. It follows that the solution is not simple, economical, and is bulky axially due to the grooved mounting of the disc on the guide ring. In addition, the supply to the variable volume chamber must be carried out using inclined channels formed, in a known manner, in said ring, said channels having to be implanted so as to take account of the presence of the disc and the grooves. , which is likely to increase the axial size between the piston

and the transverse wall.

  In practice, the channels open out between the grooves and the piston so that a distance has to be observed. This increases the axial size. In addition the

  disc should be relatively thick.

  The object of the present invention is to overcome these drawbacks in a simple and economical manner while continuing to benefit from a good ease of

  sliding of the piston along the guide ring.

  According to the invention a hydrokinetic coupling device with locking clutch of the above-mentioned type is characterized in that the drive part has an internal portion extending radially below the piston, in that said internal portion is linked in rotation with at least one of the guide ring elements - transverse wall radially below the piston and in that said internal portion is adjacent to one of the guide ring elements - wall

1o transverse.

  Thanks to the invention the passage of the fluid is not hampered since the drive part is adjacent to one of the elements transverse wall guide ring. A large passage therefore exists between the drive part and the piston. Furthermore, the internal portion can abut against the transverse wall or the guide ring because it is adjacent to one of them. As a result, the drive piece may be thin, which favors the formation of tongues

  tangentials coming directly from the drive part.

  Thanks to the invention, material falls are reduced since the connection in

  rotation is carried out radially below the piston.

  This connection, moreover, is easy to carry out. We can achieve such

  connection at the end of the ring (at the free end thereof).

  So we take advantage of the front of the ring leaving the scope intact

  guide offered by the ring at its outer periphery.

  Thus the internal portion of the drive piece can mesh with the front end of the ring, this drive piece being wedged axially between the ring and the transverse wall, so that the drive piece is integral with

  the ring - transverse wall assembly.

  As a variant, the internal portion is fixed by gluing, welding, crimping or

riveting on the ring.

  Many possibilities are offered. So the internal portion can be

  fixed by welding, crimping, gluing or riveting on the transverse wall.

  As a variant, the internal portion can be fixed at the end to the transverse wall and to the centralizer of the guide ring, said internal portion then having to do this, at its internal periphery, an annular rim of orientation

3 5 axial.

  In all cases, it is possible to form a subset in advance

  comprising at least the drive part coupled by the tongues to the piston.

  In all cases the drive part is integral with the assembly

  ring - transverse wall with elimination of axial and circumferential clearances.

  The guide ring can be of the standard type.

  In one embodiment, said internal portion is attached to the transverse wall. The drive piece is supported by the transverse wall since it is attached to the latter.

  The drive piece can thus be even thinner.

  In addition, this promotes the reduction of the axial size.

  The appended figures illustrate the invention with reference to the appended drawings in which FIGS. 1 to 4 are half-views in axial section of part of the hydrokinetic coupling apparatus showing the locking clutch and the

  drive parts according to the invention.

  Figure 5 shows part of the torsional damper.

  As is known, a hydrokinetic coupling device comprises, arranged in the same sealed housing filled with oil and forming a housing, a

  torque converter and locking clutch 1.

  The torque converter includes a turbine wheel, an impeller wheel and a reaction wheel. The impeller has blades integral with a first half-shell tightly secured with a second

  drive half-shell suitable for being linked in rotation to a driving shaft.

  The turbine wheel also has blades facing the blades of the impeller wheel. This turbine wheel is integral with a hub capable of being linked

rotating to a driven shaft.

  The drive half-shell has a generally transversely oriented wall. The turbine wheel is located axially between said

  transverse wall and the impeller.

  The locking clutch 1 is located axially between the assembly

  turbine wheel - turbine hub and this transverse wall.

  The half-shells constitute the casing which, by means of its half

  drive shell, constitutes the input element of the hydrokinetic coupling device, while the turbine hub constitutes the output element of said device. In the case of an application for a motor vehicle, the driving shaft is formed by the crankshaft of the internal combustion engine of the vehicle, while the driven shaft is formed by the input shaft of the vehicle transmission. This shaft is centrally hollow to form a supply channel for a variable-volume control chamber delimited by parts belonging to the locking clutch comprising a disc linked in rotation disengageably to the assembly.

turbine wheel - turbine hub.

  When the vehicle starts, the turbine wheel is driven in rotation by the impeller wheel thanks to the circulation of the oil contained in the sealed casing

  between the blades of the turbine and impeller wheels.

  The lockup clutch is then disengaged and the torque converter in service. To avoid a loss of efficiency due in particular to sliding phenomena between the turbine and impeller wheels, the turbine wheel is then secured to the drive half-shell after starting the vehicle by means of the locking clutch which is then engaged, the converter

o10 then being out of service.

  All this is well known to those skilled in the art and for more details,

  refer for example to document WO-A-94/07058.

  Here for simplicity only the essential elements have been represented and in

  all figures the common elements will be assigned the same reference sign.

  Thus in these figures, we see at 1 the locking clutch, at 2 the generally transversely oriented wall of the drive half-shell 3, at 4 the turbine wheel and at 5 the turbine hub secured by riveting of the wheel of

turbine 4.

  This hub 5, forming the output element of the hydrokinetic coupling device, is internally grooved for its rotational connection to the driven shaft

not shown.

  The drive half-shell 3, here in stamped sheet metal, has at its outer periphery an annular rim of axial orientation for its sealingly attachment to the other half-shell (not shown) forming an impeller. This rim extends the transverse wall 2 with a central hole and carrying screws (not referenced) at its outer periphery for rotationally connecting the half-shell 3 to the crankshaft

  of the vehicle engine, in known manner, via a non-visible flange.

  The locking clutch 1 is located axially between the assembly

  turbine wheel 4 - turbine hub 5 and the transverse wall 2.

  This clutch 1 comprises a piston 9, drilled centrally and mounted axially movable with sealing along the guide ring 6, forming a hub,

  axially interposed between the hub 5 and the wall 2.

  The piston 9 defines with the guide ring 6 and the transverse wall 2 a control chamber 30 with variable volume delimited externally by a disc 10 and friction linings 11 adapted to be tightened respectively

  between the piston 9 and the disc 10 and between the disc 10 and the transverse wall 2.

  Each friction lining 11 is integral with one of the disc elements 10 respectively piston 9 - transverse wall between which it is intended

to be tight.

  Thus one of the linings 11 can be fixed, for example by gluing, on

  the piston 9 and the other lining be fixed, for example by bonding to the wall 2.

  Here the friction linings 11 are fixed on the disc 11 on the side and

  other of it, for example by gluing or soldering.

  The disc 10 forms the output element of the locking clutch 1. This disc 10 extends radially above the piston 9, here in pressed sheet metal. This piston 9 has at its outer periphery a plane bearing of transverse orientation for the formation of a first friction face for the adjacent friction lining 11. The transverse wall 2 has, facing this bearing of the piston, 1o also a plane bearing of transverse orientation for the formation of a second

  friction face for the other friction lining 11.

  Of course as a variant, this second friction face can be formed at

  favor of an integral part, for example by welding, of the wall 2.

  The piston 9 is inclined from its first external friction face to its internal periphery, provided with a guide sleeve (not referenced) for sliding

  axial of the piston along the guide ring 6.

  Thus the internal periphery of the piston 9 is in intimate contact with the external periphery of the guide ring 6 with the interposition of a seal

  29 mounted in a groove in the ring 6.

  This ring 6 is provided centrally with a blind hole and has passages for communication between the control chamber 30 and the blind hole in the ring 6. This blind hole is in communication with the driven shaft provided with a channel food. The piston 9 delimits by its face turned towards the wall 2 the chamber 30 and

  by its face facing the turbine wheel 4 a main control chamber.

  Thus by varying the pressures in said chambers, the piston 9 is allowed to slide axially along the ring 6 and to approach the wall 2 to tighten the friction linings 11 or to move away from the wall 2 to release said linings. In the first case, the locking clutch 1 is engaged or bridged, while in the second case, the locking clutch 1 is disengaged or disassembled, knowing that the disc 11 is rigidly or resiliently connected to

  the turbine wheel 4 - turbine hub 5 assembly.

  It will be noted that a thrust ball bearing 80, of axial orientation, is interposed

  between the hub 5 and the guide ring 6.

  More specifically, the stop 80 is interposed between, on the one hand, the web, which has the hub 5 in one piece at its outer periphery for fixing by riveting, alternatively by welding to the turbine wheel 4 and, d on the other hand, the dorsal face of the ring 6, hollowed out for penetration of the free non-grooved end of the hub 5

inside the ring 6.

  A plain bearing 81 is housed in the recess of the ring, being interposed radially between the free end of the hub 5 and the ring 6 as visible in FIG. 1. When the clutch 1 is tightened, the turbine wheel 4 is coupled to the wall 2 so that no relative movement occurs between the impeller and impeller wheels. When the clutch 1 is disengaged, the turbine wheel 4 is driven

by the impeller.

  In known manner, the piston 9 is secured in rotation to the transverse wall, rotatable and fixed axially, by means of elastic tongues 40 secured to a drive part 44, so that the piston 9 is linked in rotation to the transverse wall 2 while being able to move axially relative to the latter in

  sliding axially along the ring 6.

  By simplicity is meant here, by tongues, that is to say intervening tongues

  in isolation, that is, tongues resulting from a stacking of elementary tongues.

  Here the elastic tongues 40 are of tangential orientation and are fixed by riveting at one of their ends to the piston 9 and at their other end to the part.

44.

  These tabs 40 are regularly distributed circularly in a known manner. Here we see only one tab 40, but in reality four tabs 40, regularly distributed, are provided, as visible for example in document WO 96/14526 to which reference may be made. Note that the piston 9 is stamped locally in the direction of the transverse wall 2 for fixing the tabs

  2 5 elastic 40. The stamping of the piston stiffens it.

  These tabs 40 are fixed to the drive piece 44 in favor of

  lugs 144, which has said part 44 at its outer periphery.

  Thus, there are formed clearances between the legs 144 allowing access to the piston 9 for fixing by riveting the tongues 40 to the piston 9. These tongues 40 are here previously fixed by riveting to the legs 144. It is possible

  thus to form in advance in all the figures a sub-assembly of tongues 40 -

  piston 9 without having to use two-part fixing means to intervene only on one side of the piston as described in the aforementioned document WO 96/14 526. Of course, as described in this document, the elastic tongues can be in one piece with the drive part, being obtained by cutting. As a variant, instead of being metallic, the drive part may be made of composite material while being in one piece with the drive part. The

  tongues 40 may alternatively be inclined.

  In all cases the drive piece 44 and the tongues 40 are arranged in the variable-volume control chamber 30, between the piston 9 and the

wall 2.

  It will be noted that the wall 2 is stamped locally outwards at the level of the tongues 40 and that this wall comprises at its internal periphery an axial orientation sleeve 50 delimiting the central hole of the wall 2 used for mounting the

  ring 6 as described below.

  It will be noted that the guide sleeve of the piston 9 is directed axially

  towards the wall 2, that is to say in the same direction as the sleeve 50.

  The disc 10, located at the outer periphery of the piston 9, has at its outer periphery radial lugs here offset axially in the direction of the turbine wheel 4 relative to the main part of the disc 10 carrying the friction linings 11. These lugs each have a notch into which a lug 14 (FIG. 5) penetrates, which has a part 12 coupled to the wheel 4 and hub assembly.

is turbine 5.

  The disc 10 is thus linked in rotation, with the possibility of axial movement,

  by a cooperative link of tenon-mortise type shapes.

  The part 12 can be directly fixed, for example by welding on the turbine wheel 4, in which case the disc 10 is rigidly coupled to the wheel.

turbine 4.

  Here the part 12 belongs to a torsional damper 20 so that the disc 10 is coupled elastically to the turbine wheel 4 - hub assembly

  of turbine 5. This part 12 forms a guide washer.

  The torsional damper 20 is here of the type described in the document.

  FR 97 04186 filed March 28, 1997.

  Thus the torsion damper comprises two guide washers 12,17 fixed together at their internal periphery by spacers (not referenced) and which hold coil springs 16, whose circumferential ends are in

  bearing against bearing surfaces of the guide washers 12.17.

  A flange 19 is interposed between the guide washers 12, 17 and carries on its outer periphery radial lugs forming support portions for the

  circumferential ends of the springs 16.

  One of the washers, called the first guide washer, namely the washer 12, carries on its outer periphery axially oriented drive tabs penetrating into the aforementioned notches of the outer tabs of the disc 10. The other guide washer 17, called the second guide washer, has a transverse portion which, at its outer periphery, has fixing notches in which penetrate pins of axial orientation belonging to an annular portion of axial orientation of the first guide washer 12 for a connection by crimping of the tenon-mortise type between the two guide washers, as visible in FIG. 5. The tenons are thus distinct from the drive lugs

  referenced at 14 in this figure.

  The flange 19 is fixed to the turbine hub 5, here by welding. The spacers cross the flange through oblong openings thereof. Of course the torsion damper can have another shape, for example

  example of the type described in document WO-A-94/07058.

  Here, according to a characteristic of the invention, the drive part 44 extends radially below the piston 9 to be linked in rotation to at least one

  lo of the elements guide ring 6 - transverse wall 2.

  The rotational connection is therefore located radially below the piston 9. This washer is thus economical because, compared to the solutions described in document WO 96/14526, advantage is taken of the material drop. Material losses are thus reduced. In addition, the drive part 44, here in the form of a tortuous washer, has an external diameter smaller than that of this document.

  WO 96/14526 and is therefore more economical.

  It will be noted that the guide ring 6 is provided with a centering nose 7 stepped in diameter, projecting axially towards the wall 2 and passing through the central hole of

said wall 2.

  The ring 6 has in one piece a flange 8 of axial orientation at its outer periphery. The nose 7 is in one piece with the ring 6. The flange 8

  is parallel to the nose 7 and is directed towards the wall 2.

  In this flange 8 it is formed notches or notches (not referenced) for passage of the control fluid from the inside of the ring to the

  control chamber, so that the flange 8 is indented.

  To do this, the nose 7 has holes 15 inclined in communication with said scalloped collar 8 of height greater than its width. The

  notches in the collar 8 are radially oriented.

  The flange 8 is parallel to the nose 7 and extends radially above the latter.

  This flange 8 has an outer diameter smaller than that of the ring 6.

  Thus the guide range, which the ring 6 offers at its outer periphery at

piston, is of minimum length.

  In all the figures, the drive part 44 extends radially inwards in the direction of the axis of axial symmetry XX of the device, and this radially below the piston 9 and the external periphery of the flange 8 with advance formation of a sub-assembly comprising at least the piston 9 and the part

  drive 44 coupled to the piston by the tongues 40.

  The drive part 44, generally in the form of a washer, follows the contour of the transverse wall 2 and has, at its internal periphery and at its external periphery, a portion of transverse orientation. These portions 344, 444 are offset axially with respect to each other and are connected to each other by an inclined zone 244. The external portion 344 is provided with fixing lugs 144 or, as a variant, is of in one piece with the tongues 40. This portion 344 is at a distance from the transverse wall 2. The internal portion 444 is adjacent to the transverse wall 2 and

  is axially offset in the direction of the hub 5 relative to the external portion 344.

  In the figures illustrated, the internal portion is attached to the transverse wall. Thus the drive piece 44 is well supported and may have a small thickness. It is for this reason that the tangential tabs 40 can be

  in one piece with the drive piece.

  In the embodiment of FIG. 1, the internal portion 444 has internally, at its internal periphery, an annular rim of axial orientation 544

  directed axially outwards.

  Thus during assembly, a sub-assembly is formed comprising the piston 9, the drive part 44 coupled to the piston 9 by the tongues 44 and the guide ring, the portion of which has the largest diameter of its nose 7 forms a centering device. for flange 544, the internal periphery of which is in intimate contact with the external periphery

  of the larger diameter portion of the centering device 7. After fitting this sub-

  together in the central sleeve 50 of the transverse wall 2.

  The outer periphery of the flange 544 then comes into intimate contact with the internal periphery of the sleeve 50. Then the flange 544 is welded to the end.

  sleeve 50, then edge 544 is welded to the end 7.

  Two welding seams 45,145 thus appear at the level of the

  free ends of the rim 544 and of the sleeve 50. This welding is carried out here with a laser.

  Thus the drive part is integral with the ring 6 and the wall 2 by means of its flange 544 and two welds are necessary for the

  fixation. The rim 544 is interposed radially between the sleeve 50 and the centralizer 7.

  The internal portion 444 is interposed axially with clamping between the

  flange 8 and the transverse wall 2.

  As a variant, a sub-assembly comprising the piston and the drive part is mounted on the wall 2 by welding at 45, then the guide ring 6, shaped as a centering device, is threaded into the flange 544 and then proceed to the

welding in 145.

  In FIG. 2, the number of welds is increased to form a sub-

  guide ring assembly 6 - piston 9 - drive part 44 coupled by the

tabs 40 on piston 9.

  This subset is captive. To do this, the internal portion 444 of the drive piece 44 is welded to the end (at the free end facing the wall 2) of the flange 8 using two welding beads 345,445 offset radially. Then this sub-assembly is threaded into the sleeve 50 of the wall 2, finally carrying out a welding in 555 of the centering device at the end of the sleeve 50, the internal periphery of which is then in intimate contact with the external periphery of larger

1o diameter of the centering device 7.

  It will be appreciated that the fixing of the drive part 44 is carried out over a larger diameter and is therefore more robust. The internal portion 444 is also

  sandwiched between the wall 2 and the flange 8.

  The drive piece is simplified since it has no flange

axial at its internal periphery.

  In this figure, the tongues 40 are fixed after the fixing

  of portion 444 on the flange 8.

  In Figure 3 we make the same subset as in Figure 2 and we

  finally welds in 555 the centering device 7 at the end of the sleeve 50 of the transverse wall 2.

  Here the sub-assembly is not captive because the internal periphery of the internal portion 444 of the drive part is provided with a toothing to mesh with a toothing produced in the flange 8 at the end thereof. The flange 8 is then stepped in diameter to present at its free end a portion of smaller

  diameter with the aforementioned teeth.

  After welding of the centering device 7 at 555, the drive part is interposed axially between the portion of larger diameter of the ring 6 and the wall 2, so

  that it is immobilized axially and that we remove the games.

  The drive part is therefore linked in rotation to the guide ring 6.

  Note that the toothing of the collar is shorter than that of the

  3 o internal portion so that the collar 8 is not in contact with the wall 2.

  In FIGS. 1 to 3, the centering device 7 serves to center the locking clutch 1 on the wall 2 in the end. More precisely, the nose 7 serves as the piston centering device 9 and

  clamping member for clamping the internal portion 444 in contact with the wall 2.

  In all cases, the disc 10 with its linings 11 is inserted axially.

  between the piston and the wall 2 before carrying out the final fixing of the centering device 7. As a variant, in FIG. 4, a piston 9 - part sub-assembly is formed

  drive 44 coupled to the piston 9 by the tongues.

  Then the outer periphery of the piston 9 is centered relative to the axial rim of the drive half-shell 3 and then the internal portion 444 of the part 44 is welded by transparency to the wall 2. This welding is carried out radially below

  of the piston 9 in the vicinity of the internal periphery of the internal portion 444.

  In this case the flange 8 is stepped in diameter to come, radially below the drive part 44 of the tongues 40, directly in contact with the wall 2 by its part of smaller diameter. The internal portion 444 is then

  axially away from the larger diameter portion of the flange 8.

  As a variant, the internal portion 444 can be centered directly by the wall 2 and this is the reason for showing in FIG. 4 a recess.

  allowing to center the internal periphery of the portion 444.

  Of course, the welds can be replaced by bonding.

  In FIG. 4, the internal portion 444 can be fixed by riveting to the wall 2.

  The rivets are then obtained by extrusion of the wall 2 as visible in the

document WO 96/14526.

  In FIGS. 2 and 3, the internal portion can be fixed by riveting on the

  flange 8 to form a captive sub-assembly.

  Of course it is then necessary to drown the heads of the rivets in the internal portion.

  It can be seen in the light of FIG. 4, by inversion of structure, that the internal portion 444 can be fixed by welding or riveting to the flange with the appearance of a clearance between the portion 444 and the wall 2. In this case the portion 444 is adjacent to the

  wall 2 without being attached to it.

  All combinations are possible. For example, the rim 544 of the part 44 can be welded in the end on the centralizer 7 after having carried out a transparent welding or riveting of the internal portion 444 on the wall 2 as in FIG. 4. In FIG. 3 the end free of smaller diameter of the collar 8 can be devoid of teeth. The toothing of the internal portion 444 is then forcibly inserted into said free end forming the portion of smaller diameter of the flange 8. During this operation the toothing of the portion 444 cuts the grooves in the flange 8 and it is the reason why a groove has been represented in FIG. 3 at the level of the connection zone of the part of smaller diameter of the flange 8

  to the larger diameter portion thereof.

  Thus the material of the flange 8 can flow in said groove when

  press-fit the internal portion 444 onto the flange 8.

  This results in a fixing by crimping the drive piece on the

  guide ring 6. This embodiment makes it possible to cancel any axial and circumferential play.

  As a variant, the internal portion 444 may be adjacent to the ring of

guide 6 proper.

  More specifically, this internal portion 444 can be engaged in the bottom

  notches, which has the collar 8 above.

  The internal portion 444 then has tabs penetrating the bottom of said notches to be fixed for example by welding or riveting to the ring 6. In all cases the internal portion 444 delimits the fluid passages in connection with the flange 8. The circulation fluid is therefore not hampered by the drive part 44. The drive part is therefore linked in rotation to at least one of the elements transverse wall 2 - ring 6. It can be fixed to these two elements 1o (Figure 1), or one of these (Figures 2 and 3). It is then linked in rotation and

axially to this element.

  In all cases, its rotational connection zone is produced radially below the piston, so that the guide range offered by the guide ring

to the piston is not affected.

  In all the figures the passage of the fluid from the interior of the ring 6 to the chamber 30 is not hindered since the drive part is adjacent to the wall 2

or ring 6.

  In FIGS. 1 to 4, the drive part is inserted without play or with play between the flange 8 and the wall 2. It will be noted that the splined mounting is eliminated from document FR-A-2 634 849. In practical these grooves are longer than the thickness of the drive piece so that we save space

in axial dimensions.

  Thus, despite the insertion of the internal portion between the ring and the wall, the axial size is reduced. This is all the more so as the internal portion can be thin and be attached to the transverse wall which eliminates any play

axial at this level.

  In the present invention, the tongues 40 provide the axial clearance

piston 9.

  It will also be noted that, thanks to the invention, all the axial and circumferential clearances are eliminated. Indeed in the embodiment of Figure 3, we just tighten the portion 444 between the wall 2 and the flange 8 so that we remove all

Games.

  In the other figures, the games are eliminated since a fixing is carried out. It is the same in the variant in which the internal portion 444 is fixed in the bottom of the notches of the collar 8 in the form of notches or

  notches in the aforementioned manner.

  Of course the guide ring can have the shape of that described in

document FR-A-2 634 849.

  In all cases, the guide ring 6 passes centrally through the transverse wall 2 and the internal portion is, radially beyond the centering nose of the ring 6, axially interposed with or without clamping between, on the one hand, the face front of the ring 6, facing the wall 2 and forming the tip or the free end of the said

  ring and, on the other hand, the transverse wall 2.

  Of course, means are provided to avoid pollution, in particular

  when carrying out welding operations.

  This is facilitated by the location of the rotating link below the

* guide range offered by the ring at its outer periphery to the piston.

Claims (12)

  1- hydrokinetic coupling device, in particular for a motor vehicle, comprising a wall of generally transverse orientation (2) suitable for being linked in rotation to a driving shaft and carrying centrally attached a guide ring (6) passing through said wall for form a centralizer (7), a piston (9) mounted axially movable with sealing along the guide ring (6) and defining with said ring (6) and said transverse wall (2) a variable volume control chamber ( 30) delimited externally by a disc (10) and friction friction linings (11) adapted to be clamped respectively between the piston (9) and the disc (10) and between the disc (10) and the transverse wall (2) , each friction lining (11) being integral with one of the disc elements (10) respectively piston (9) - transverse wall (2) between which it is intended to be clamped, in which the piston (9) is linked in wall rotation transv ersale (2) with axial mobility, by means of tangential elastic tongues (40) integral with a drive part (44), characterized in that the drive part (44) has an internal portion (444) extending radially below the piston (9), in that said internal portion (444) is linked in rotation to at least one of the elements guide ring (6) - transverse wall (2) radially below the piston (9) and in that said internal portion (444) is adjacent to one of the elements transverse wall (2) - ring guide (6).   2- Apparatus according to claim 1, characterized in that said internal wall (444) is adjacent to the transverse wall (2), so that it is interposed   axially between the guide ring (6) and the wall (2).   3- Apparatus according to claim 1 or 2, characterized in that the internal portion (444) of the drive piece (44) is interposed axially between the transverse wall (2) and a flange (8) that has an axial projection the guide ring (6) in the direction of the transverse wall (2) and in that said flange (8) is provided with notches for passage of the supply fluid from the control chamber to   3 o variable volume (30) and extends parallel to the centralizer (7).   4- Apparatus according to claim 3 and 1, characterized in that the internal portion (444) has tabs engaged in the bottom of the notches of the   flange (8) while being fixed to the ring (6).   - Apparatus according to any one of claims 1 to 4, characterized in   that the internal portion (444) of the drive part (44) is linked in rotation and axially to at least one of the elements of the guide ring (6) - transverse wall (2)   radially below the piston (9).   6- Apparatus according to claim 5, characterized in that said internal portion (444) has at its internal periphery an annular flange (544) of axial orientation fixed at the end, on the one hand, on a central sleeve (50) d axial orientation which the transverse wall (2) has centrally and, on the other hand, on the centralizer (7) of the guide ring (6), said flange (544) being interposed radially between said sleeve (50) and said centralizer (7).   7- Apparatus according to claim 6, characterized in that the fixing is produced by welding.   8- Apparatus according to claim 5, characterized in that said portion   internal (444) is fixed to said transverse wall radially below the piston (9).   9- Apparatus according to claim 8, characterized in that the attachment is   lo produced by laser type transparency welding.   - Apparatus according to claim 5, characterized in that said portion   internal is fixed at the end of the collar (8).   11- Apparatus according to claim 10, characterized in that the attachment is produced by welding.   12- Apparatus according to claim 3, characterized in that the flange (8) of the guide piece (6) is stepped in diameter and in that the portion of smaller diameter of the flange has a toothing to mesh with a toothing than   presents the drive part (44) at its internal periphery.   13- Apparatus according to claim 3, characterized in that the flange (8) of the guide piece (6) is stepped in diameter and in that the drive piece (44) has at its internal periphery a toothing for cutting grooves in the smaller diameter part of the flange (8), so that the part   drive (44) is fixed by crimping to the guide ring.   14- Apparatus according to any one of claims 1 to 3 and 5 to 13,   characterized in that the internal portion (444) is attached to the transverse wall.