Title of Invention

"A FRICTION CLUTCH IN PARTICULAR FOR A MOTOR VEHICLE INCLUDING MULTI-FUCTIONAL MEANS"

Abstract

The invention concerns a clutch comprising a pre-damper (A2) and a main damper (Al). Each damper is provided with rotary input (18) and output (18, 14) elements, two guide rings (16a, 16b, 32a, 32b) secured in rotation to one first element selected among its input (18) and output (18, 14) elements, a plate (15, 35) secured in rotation to the second of said elements, friction means biased by relative angular displacement of the plate (15, 35) and of guide rings (16a, 16b, 32a, 32b). The pre-damper includes a multifunctional member (33) for centering the guide rings (32a, 32b) of the pre-damper (A2) relative to its input element (8) and for securing in rotation the input element (18) of the pre-damper (A2) to the guide rings (32a, 32b) of said pre-damper (A2). The multifunctional member (33) further serves to guide in rotation the output element (14) of the pre-damper (A2) relative to its input element (18) and/or to ensure friction for the friction means of the pre-damper (A2).

Full Text

INTERNATIONAL PATENT APPLICATION NO. PCT/FR2004/050431, PUBLICATION NO. WO2005/026575 A FRICTION CLUTCH, IN PARTICULAR FOR A MOTOR VEHICLE, INCLUDING MULTI-FUNCTION MEANS The present invention relates to a friction clutch, in particular for a motor vehicle, which includes multi-function means. In a motor vehicle, the function of a friction clutch is to transmit a torque between a rotatable input member and a rotatable output member, by gripping the friction means of the clutch between a pressure plate and an engine flywheel, while ensuring the continuity of the said torque and damping out the vibrations that come from the engine. In general, the input element consists of a clutch friction disc, while the output element consists of a hub which, in particular, is adapted to be coupled to an input shaft of the gearbox. It is known in the current state of the art, and in particular from the document FR-A-2 689 191 (FR/92 03638), to provide a friction clutch, in particular for a motor vehicle, of the type comprising two dampers which are coupled together in series, namely a predamper and a main damper, each of which has a rotatable input element and a rotatable output element, the output element of the main damper being also the input element of the predamper, wherein each of the two dampers includes two guide rings which are coupled in rotation to a first element selected from among its input elements and output elements, a damper plate which is coupled in rotation to the second one of the said elements, friction means which are actuated by relative angular displacement of the damper plate and guide rings, the predamper further including multi-function means having the following functions: - centring the guide rings of the predamper with respect to its input element, and - coupling the input element of the predamper with the guide rings of the said predamper, for rotation together. In that document, the multi-function means consist of pins which connect the guide rings with the output element of the damper, and which provide the two functions of centring and coupling together in rotation. The fitting of these pins is usually carried out in the course of a relatively complex and lengthy operation. A particular object of the invention is to provide a remedy for this problem by providing a friction clutch having multi-function means which are adapted to be assembled easily and quickly, while reducing as much as possible the number of components in the clutch. With this in view, the invention provides a friction clutch, in particular for a motor vehicle, of the type set forth above, characterised in that the multi-function means comprise a multi-function member which furthermore performs at least one of the following functions: - guiding the output element of the predamper in rotation with respect to its input element, and - providing friction for the friction means of the predamper. Due to the fact that a single and common multi-function member performs several functions, the fitting and the structure of the clutch are simplified. Preferably, the multi-function member is of generally annular form, and is substantially coaxial with the input element and output element of the predamper. Thus, the multi-function member is of simple construction, and enables the various components of the clutch to be assembled together by telescoping them over the said multi-function member. In addition, the multi-function member, which has a generally annular form, enables the size of the clutch to be limited. According to further optional features of the said friction clutch: - the multi-function member has a first end which is in contact with the damper plate of the predamper, and which is delimited by a friction face for frictional contact with the damper plate; - the first end of the multi-function member is disposed axially between the two guide rings of the predamper; - the input element and output element are of generally annular forms, defining an outer hub and an inner hub respectively, the said hubs being substantially coaxial, and having the multi-function member interposed radially between them, whereby to provide centring for the output element of the predamper with respect to its input element; - at least one of the guide rings and the input element have internal contours adapted for securing them in rotation and for cooperating with complementary external contours of the multi-function member; - the contour of the multi-function member for securing it in rotation with the input element extends axially outside the space defined between the two guide rings of the predamper; - the multi-function member and the output element of the predamper are delimited by complementary surfaces defining an inner bearing and an outer bearing respectively, for ensuring that the said output element of the predamper is guided in rotation with respect to the input element of the predamper which is coupled for rotation with the multi-function member; - the input element of the predamper has an end which is opposed axially to the multi-function member and which is coupled in rotation, for example in a dog clutch relationship, with a guide ring for guiding the output element of the predamper in rotation with respect to the input element of the predamper; - each damper includes elastic members acting circumferentially and mounted in windows formed in the guide rings and the damper plate, and at least one of the resilient members is mounted with a circumferential clearance in a corresponding window of the damper plate, whereby to constitute first and second damping stages; - the friction means of each damper include a friction ring having two lugs which, when the resilient member having a circumferential clearance is in a rest position, is in circumferential engagement with one end of the said resilient member having circumferential clearance, whereby the said friction ring is driven in rotation when the second damping stage is activated; - each lug of the friction ring of the predamper prevents any direct contact taking place between the damper plate of the predamper and the end of the resilient member with which the lug is in circumferential engagement; - the friction means of the main damper comprise at least one flat friction ring having lugs for securing it in rotation with the output element of the main damper and radially extending the length of the internal contour of the said flat ring; - the flat friction ring is in contact with the damper plate of the main damper, and is delimited by a friction face for frictional contact with the said damper plate; - the flat friction ring is in contact with the lug-bearing friction ring, and is delimited by a face which is in frictional contact with the said lug-bearing ring when the second damping stage of the main damper is activated; - the two guide rings of the main damper are fixed with respect to the output element of the said main damper, the two guide rings of the predamper being disposed axially outside the space defined between the two guide rings of the main damper; - the friction clutch includes a resilient ring which is interposed axially between the predamper and the main damper, and which is adapted to apply a force for urging the multi-function member into frictional engagement against the damper plate of the predamper, and which contributes to the axial positioning of the main damper; - the resilient ring surrounds the output element of the predamper and elastically returns the output element of the main damper axially into engagement, directly or indirectly, against an axial positioning abutment element of the said output element of the main damper; - the resilient ring is provided with means for securing it in rotation with the multi function member. The invention will be understood more clearly on a reading of the following description, which is given by way of example only and with reference to the attached drawings, in which: - Figure 1 is an exploded perspective view of a clutch according to the invention; and - Figure 2 is a view in axial cross section of the clutch shown in Figure 1. The drawing shows a friction clutch according to the invention. In the example to be described, the clutch is for a motor vehicle. The friction clutch comprises a friction wheel assembly 10 for transmitting a torque between an engine flywheel, which is coupled with a driving shaft such as the crankshaft of an internal combustion engine, for rotation with it, and a driven shaft such as the input shaft of a gearbox. The friction wheel assembly 10 is provided with damping means which comprise a main damper A1 and a predamper A2. These dampers A1 and A2 are coupled in series with a general rotary input element, such as a clutch friction wheel 12, and a general rotary output element such as an inner hub 14 which is of generally annular form, the said input and output elements being substantially coaxial with each other. In the known way, the clutch friction wheel 12 is arranged to be gripped between the engine flywheel and a pressure plate which is actuated by clutch-engaging means. The inner hub 14 has internal longitudinal splines by means of which it can be coupled in rotation with one end of the driven shaft. Each damper A1, A2 is formed with rotary input and output elements, so that a torque which enters through the input element is transmitted to the output element after being damped. The input element of the main damper A1 is the general input element of the friction wheel assembly 10, that is to say it is the friction wheel 12. The friction wheel 12 is fixed on a damper plate 15 of the main damper A1, for example by means of rivets. The damper plate 15 is arranged between two guide rings 16a and 16b of the main damper A1, coaxially with these latter. The guide rings 16a and 16b are coupled in rotation, for example by welding, with an outer hub 18 which acts as the output element of the main damper A1. The outer hub 18 is annular in form, and it is substantially coaxial with the inner hub 14. Circumferentially acting resilient means, such as helical springs 20a, 20b, 22a and 22b, with a high stiffness, are mounted in windows 24 in the guide rings 16a and 16b and in windows 26 in the annular damper plate 15. The resilient members 20a and 20b are arranged in groups, for example two groups as here. The resilient members 20a and 20b of a first group are mounted without any circumferential clearance in the windows 24 and 26 mentioned above, and play a part in the transmission of a rotary torque between the guide rings 16a and 16b and the damper plate 15, as from the start of a relative rotational movement between the clutch friction wheel 12 and the outer hub 18. The resilient members 22a and 22b in a second group are mounted, without any circumferential clearance, in the windows 24 in the guide rings 16a and 16b, but with a predetermined circumferential clearance in the windows 26 of the annular damping plate 15, and they do not take any part in the transmission of a rotary torque, except when the angular displacement, starting from a rest position, between the guide rings 16a and 16b and the annular damper plate 15 exceeds a predetermined valuewhich corresponds to the circumferential clearance between the resilient members 22a and 22b on the one hand and the windows 26 of the damper plate 15 on the other. Thus, the resilient members 20a and 20b in the first group transmit the torque permanently, while the resilient members 22a and 22b in the second group only transmit it when the angular displacement between the guide rings 16a and 16b and the annular damper plate 15 is greater than the said predetermined value. The damping out of vibrations and irregularities in the torque thus takes place in two damping stages, with the resilient members in the second group only acting when the angular displacement between the guide rings 16a and 16b of the annular damper plate 15 exceeds the predetermined value. When the first damping stage of the main damper A1 is activated, the clutch friction wheel 12 drives the damper plate 15 in rotation. Its windows 26 then cause the resilient members 20a and 20b, which are mounted without any clearance, to rotate. The resilient members 20a and 20b then cause the guide rings 16a and 16b to rotate out of phase with each other, the phase offset being dependent on the stiffness of the resilient members 20a and 20b. The outer hub 18, fixed with respect to the guide rings 16a and 16b, is itself also rotated. in parallel with the activation of the resilient members, friction means are brought into action when the first damping stage of the main damper A1 is activated. For this purpose, the main damper A1 includes flat friction rings 28a and 28b carrying lugs which are radial extensions of the internal profile of these flat rings, and which are adapted to cooperate with external teeth of the outer hub 18, so that they couple the rings 28a and 28b with the hub 18 for rotation with the latter. The flat friction rings 28a and 28b are in contact with the damper plate 15 of the main damper A1, and they have faces for frictional contact with the damper plate 15, the gripping force between the friction rings 28a and 28b being provided by a resilient ring 30, for example a Belleville ring or a corrugated ring, which is interposed axially between the guide ring 16b and the friction ring 28b. When the angular displacement, with reference to the rest position, between the guide rings 16a and 16b on the one hand and the annular damper plate 15 on the other exceeds the predetermined value, the second damping stage of the main damper A1 is activated. The resilient members 28a and 28b are then also caused by the damper plate 15 to rotate, and their stiffnesses are thereby added to the stiffnesses of the resilient members 20a and 20b, and thereby contribute to the phase offset between the guide rings 16a, 16b and the damper plate 15. The main damper A1 further includes a friction ring 31 which is formed with two pairs of lugs 31 P. The lugs 31P of one pair are in circumferential contact with the ends of a corresponding resilient member 22a or 22b when the latter is in its rest position. Each lug of the friction ring 31 is arranged to cooperate with the inner surface of the corresponding window 26, in such a way that this friction ring 31 is driven in rotation when the second damping stage of the main damper A1 is activated. The lug-bearing ring 31 is interposed between the guide ring 16a and the flat friction ring 28a, so as to constitute, with those two rings, two supplementary friction faces. These two damping stages of the main damper A1 constitute the third and fourth damping stages of the friction wheel assembly 10, the two first damping stages of the friction wheel assembly 10 being provided by the predamper A2. The predamper A2 provides coupling between the outer hub 18 and the inner hub 14. It will accordingly be noted that the input element of the predamper A2 is the output element of the main damper A1, and that the output element of the predamper A2 is the general output element of the friction wheel assembly 10. The predamper A2 includes first and second guide rings 32a and 32b, which are disposed axially outside the space defined between the two guide rings of the main damper A1, One of the guide rings 32a and 32b has internal contours for coupling it in rotation in cooperation with a complementary first portion of the external contour of a multi-function member 33, the guide rings of the predamper being fitted in this example with the aid of lugs at their periphery, using a brazing process. The multi-function member 33 is of a generally annular form, substantially coaxial with the outer hub 18 and the inner hub 14, and it is interposed radially between these two hubs in such a way that it provides centring for the inner hub 14 with respect to the outer hub 18. This centring is completed by a centring ring 34 which also guides the outer hub 18 in rotation with respect to the inner hub 14, this ring 34 being coupled in rotation, for example in a dog clutch relationship, with one end of the outer hub 18 which is the end axially remote from the multi-function member 33. In addition, the outer hub 18 has an internal contour, for coupling it in rotation, which is in cooperation with a complementary second portion of the external contour of the multi-function member 33, the form of which is the same as that of the first portion of the said contour. It will therefore be seen that the guide rings 32a and 32b are coupled in rotation with the outer hub 18, because its elements are all coupled in rotation with the multi-function member 33. The second portion of the outer contour of the multi-function member 33 extends axially outside the space lying between the two guide rings 32a and 32b of the predamper A2. In addition, the multi-function member 33 and the inner hub 14 are delimited by complementary inner and outer bearing surfaces respectively, so as to ensure, with the ring 34, that the inner hub 14 is guided in rotation with respect to the outer hub 18, which is rotatable with the multi-function member 33. The predamper A2 further includes an annular damper plate 35 which is disposed between the said guide rings 32a and 32b, and which is rotatable with the inner hub 14, on which it is for example shrink-fitted. Circumferentially acting resilient members, such as helical springs 36a, 36b, 38a and 38b, of relatively low stiffness, are mounted in windows 40 in the guide rings 32a and 32b, and in windows 44 in the damper plate 35. In a similar way to the main damper A1, the resilient members 36a, 36b, 38a and 38b are arranged in groups, of which there are two in this example. Thus, the resilient members 36a and 36b of the first group are fitted without any circumferential clearance in the windows 40 of the guide rings 32a and 32b and the windows 44 in the damper plate 35, and share in the transmission of a torque as from the start of relative rotation of the outer hub 18 with respect to the inner hub 14. By contrast, the resilient members 38a and 38b of the second group are mounted without any circumferential clearance in the windows 40 of the guide rings 32a and 32b, but with a predetermined circumferential clearance in the windows of the annular damper plate 35 of the predamper A2. The said resilient members 38a and 38b in the second group therefore play no part in the transmission of rotation torque except when the angular displacement between the damper plate 35 and the guide rings 32a and 32b is greater than the above mentioned circumferential clearance. Thus, as with the main damper A1, the predamper A2 gives two damping stages. When the first damping stage of the predamper A2 is activated, the outer hub 18 drives the guide rings 32a and 32b in rotation. The windows 40 then cause the resilient members 36a and 36b to rotate, since the latter are mounted without any clearance. The resilient members 36a and 36b then cause the damper plate 35 to rotate, with a phase lag or offset which depends on the stiffness of the resilient members 36a and 36b. The inner hub 14, being fixed with respect to the damper plate 35, is also driven in rotation. In parallel with the activation of the resilient members 36a and 36b, friction means are brought into use when the first damping stage of the predamper A2 is activated. In this connection, the multi-function member 33 is fixed so as to be rotatable with the guide rings 32a and 32b, and is in contact with the damper plate 35 of the predamper A2. A resilient ring 48, which is interposed axially between the predamper A2 and the main damper A1, applies a force, in particular through the interposed guide ring 32b, to urge the multi-function member 33 into engagement against the damper plate 35 of the predamper A2. This force then ensures that the multi-function member 33 is in contact on the damper plate 35, which similarly provides friction. The said resilient ring 48 is provided in this example with means for coupling it in rotation with the multi-function member 33, these means consisting of lugs which are adapted to cooperate with the outer contour of the multi-function member 33. Another friction face is defined between the rotary guide ring 34, which is rotatable with the outer bearing 18, and a friction ring 50. When the angular displacement, with respect to a rest position, between the guide rings 32a and 32b on the one hand and the annular damper plate 35 on the other exceeds a limiting value, the second damping stage of the predamper A2 is activated. The resilient members 38a and 38b then themselves cause the damper plate 35 to rotate, and their stiffnesses are thereby added to the stiffnesses of the resilient members 36a and 36b in contributing to the phase displacement between the guide rings 32a and 32b and the damper plate 35. The predamper A2 further includes a friction ring 52 which is formed with two pairs of lugs 52P. The lugs 52P of a pair are in circumferential contact with the ends of a resilient member 38a or 38b when the latter is in its rest position. Each lug of the friction ring 52 is arranged to cooperate with the internal surface of the corresponding window 44, in such a way that the friction ring 52, firstly, is driven in rotation when the second damping stage of the predamper A2 is activated, and secondly, it prevents any direct contact between the damper plate 35 and the end of the resilient member 38a or 38b with which the lug 52P is in engagement. This lug-bearing ring 52 is interposed between the guide ring 32b and the damper plate 35 of the predamper A2, in such a way that, with the guide ring 32b, it defines a first friction face. The predamper A2 further includes a fiat friction ring 53, this ring being coupled with the lug-bearing ring 52 for rotation with it, the flat ring 53 being formed with a notch which cooperates with a complementary projecting element of the lug bearing ring 52. Thus, when the second damping stage of the predamper A2 is activated, the lug-bearing ring 52, which is driven in rotation with the damper plate 35, carries the friction ring 53 with it. The said friction ring 53 is in contact with a resilient ring 54. The resilient ring 54 is formed with lugs for fixing it to the guide ring 32a. The friction ring 53 and resilient ring 54 therefore do not rotate at the same speed, and accordingly they together define a line of friction. The two damping stages of the predamper A2 add themselves to the two damping stages of the main damper A1, so as to define four damping stages. In the event of a weak angular displacement between the input element 12 and the output element 14 of the friction wheel assembly 10, the first stage of the predamper A2, in which the resilient members 36a, 36b, 38a and 38b are of low stiffness, is activated. As described earlier herein, the second damping stage of the predamper A2 is then activated when the angular displacement between the input element 12 and the output element 14 of the friction wheel assembly 10 exceeds a certain threshold value. When the end of the second damping stage of the predamper A2 is reached, external bosses 56 of the inner hub 14 come into contact with internal bosses 57 on the inner contour of the outer hub 18, so that the torque passes directly between the inner hub 14 and the outer hub 18. The predamper A2 then no longer plays any part in the transmission of the torque, and the first and second stages of the main damper A1 are then activated in that order. In addition to performing the various functions described above, the multifunction member 33 facilitates fitting of the friction wheel assembly 10. In this connection, first of all, the damper plate 35 is fitted on the inner hub 14, in this example by shrink-fitting. The various elements of the predamper A2 are then fitted on either side of the damper plate 35 and around the inner hub 14, with a first end of the multi-function member 33 being disposed axially between the two guide rings of the predamper A2. The second end of the multi-function member 33 lies axially outside the space defined between the two guide rings of the predamper A2r which enables the outer hub 18 on which the main damper A1 is mounted to come into a capping position over the said second end. The resilient ring 48 surrounding the multi-function member takes part in the axial positioning of the main damper A1. In this connection, this resilient ring 48 biasses the outer ring 18 axially into indirect engagement via the friction ring 50 against an axial positioning abutment element of the outer ring 18, consisting of a circlip 58. In a modified version not shown, the outer ring 18 may be in direct engagement against the circlip 58. We Claim: 1. A friction clutch, In particular for a motor vehicle, of the type comprising two dampers (Al, A2) which are coupled together in series, namely a predamper (A2) and a main damper (Al), each of which has a rotatable input element (12, 18) and a rotatable output element (18, 14), the output element (18) of the main damper (Al) being also the input element (18) of the predamper (A2), wherein each of the two dampers includes two guide rings (lea, lab, 32a, 32b) which are coupled In rotation to a first element selected from among its input elements (12, 18) and output elements (18, 14), a damper plate (15, 35) which is coupled in rotation to the second one of the said elements, friction means (52, 31, 28a, 28b, 33) which are actuated by relative angular displacement of the damper plate (15, 35) and guide rings (16a, 16b, 32a, 32b), the predamper (A2) further including multi¬function means having the following functions: - centering the guide rings (32a, 32b) of the predamper (A2) with respect to its 15 input element (18), and - coupling the input element (18) of the predamper (A2) with the guide rings (32a, 32b) of the said predamper (A2), for rotation together. characterized in that the multi-function means comprise a multi-function member (33) which furthermore performs at least one of the following functions: - guiding the output element (14) of the predamper (A2) in rotation with respect to its input element (18), and - providing friction for the friction means of the predamper (A2). 2. A friction clutch as claimed in Claim 1, wherein the multi-function member (33) is of annular form, and is substantially coaxial with the input element (18) and output element (14) of the predamper (A2). 3. A friction clutch as claimed in Claim 2, wherein the multi-function member (33) has a first end which is in contact with the damper plate (35) of the predamper (A2), and which is delimited by a friction face for frictional contact with the damper plate (35). 4. A friction clutch as claimed in Claim 3, wherein the first end of the multi-function member (33) is disposed axially between the two guide rings (32a, 32b) of the predamper (A2). 5. A friction clutch as claimed in any one of Claims 2 to 4, wherein the input element (18) and output element (14) are of annular forms, defining an outer hub (18) and an inner hub (14) respectively, the said hubs being substantially coaxial, and having the multi-function member (33) interposed radially between them, whereby to provide centring for the output element (14) of the predamper (A2) with respect to its input element (18). 6. A friction clutch as claimed in any one claims 2. to 5, wherein at least one of the guide rings (32a, 32b) and the input element (18) have internal contours adapted for securing them in rotation and for cooperating with complementary external contours of the multi-function member (33). 7. A friction clutch as claimed in claim 6, wherein the contour of the multi-function member (33) for securing it in rotation with the input element (18) extends axially outside the space defined between the two guide rings (32a, 32b) of the predamper (A2). 8. A friction clutch as claimed in claim 6 or Claim 7, wherein the multifunction member (33) and the output element (14) of the predamper (A2) are delimited by complementary surfaces defining an inner bearing and an outer bearing respectively, for ensuring that the said output element (14) of the predamper (A2) is guided in rotation with respect to the input element (18) of the predamper (A2) which is coupled for rotation with the multi4unction member (33). 9. A friction clutch as claimed in Claim 8, wherein the Input element (18) of the predamper (A2) has an end which is opposed axially to the multi- function member (33) and which is coupled in rotation, for example In a dog clutch relationship, with a guide ring for guiding the output element (14) of the predamper (A2) in rotation with respect to the Input element (18) of the predamper (A2). 10. A friction clutch as claimed in any one of the preceding claims, wherein each damper (A2, Al) includes elastic members (36a, 36b, 38a, 38b, 20a, 20b, 22a, 22b) acting circumferentially and mounted in windows (40, 44, 24, 26) formed in the guide rings (32a, 32b, 16a, 1Gb) and the damper plate 30 (35, 15), and in that at least one of the resilient members (36a, 3Gb, 38a, 38b; 20a, 20b, 22a, 22b) is mounted with a circumferential clearance in a corresponding window (44, 26) of the damper plate (35, 15), whereby to constitute first and second damping stages. 11. A friction clutch as claimed in claim 10, wherein the friction means of each damper (A2, Al) include a friction ring (52, 31) having two lugs (52P, 31 P) each of which, when the resilient member (38a, 38b, 22a, 22b) having a circumferential clearance is in a rest position, is in engagement with one end of the said resilient member (38a,38b, 22a, 22b) that the friction having two lug (38a, 38b, 22a, 22b) having circumferential clearance, whereby the said friction ring (52, 31) is driven in rotation when the second damping stage is activated. 12. A friction clutch as claimed in claim 11, wherein each lug (52P) of the friction ring (52) of the predamper (A2) prevents any direct contact taking place between the damper plate (35) of the predamper (A2) and the end of the resilient member (38a, 38b) with which the lug (52P) is in circumferential engagement. 13. A friction clutch as claimed in any one of the preceding claims, wherein the friction means of the main damper (Al) comprise at least one flat friction ring (28a, 28b) having lugs for securing it In rotation with the output element (18) of the main damper (Al) and radially extending the length of the internal contour of the said flat ring (28a, 28b). 14. A friction clutch as claimed in claim 13, wherein the flat friction ring (28a, 28b) is in contact with the damper plate (15) of the main damper (Al), and is delimited by a friction face for frictional contact with the said damper plate (15). 15. A friction clutch as claimed in claims 11 and 14 taken together, wherein the flat friction ring (28a, 28b) is in contact with the lug- bearing friction ring (31), and is delimited by a face which is in frictional contact with the said lug-bearing ring when the second damping stage of the main damper (Al) is activated. 16. A friction clutch as claimed in any one of the preceding Claims, wherein the two guide rings (16a, 16b) of the main damper (Al) are fixed with respect to the output element (18) of the said main damper (Al), the two guide rings (32a, 32b) of the predamper (A2) being disposed axially outside the space defined between the two guide rings (16a, 16b) of the main damper (Al). 17. A friction clutch as claimed in any one of the preceding claims, wherein it includes a resilient ring (48) which is Interposed axially between the predamper (A2) and the main damper (Al), and which is adapted to apply a force for urging the multi4unction member (33) into frictional engagement against the damper plate (35) of the predamper (A2), and which contributes to the axial positioning of the main damper (Al). 18, A friction clutch as claimed in claim 17, wherein the resilient ring (48) surrounds the output element (14) of the predamper (A2) and elastically returns the output element (18) of the main damper (Al) axially into engagement, directly or indirectly, against an axial positioning abutment element of the said output element (18) of the main damper (Al). 19. A friction clutch as claimed in claim 18 or claim 19, wherein the resilient ring (48) is provided with means for securing it in rotation with the multi- function member (33).

Documents:

968-DELNP-2006-1-Correspondence Others-(29-02-2012).pdf

968-DELNP-2006-Abstract-(02-07-2012).pdf

968-delnp-2006-abstract.pdf

968-DELNP-2006-Claims-(02-07-2012).pdf

968-delnp-2006-claims.pdf

968-DELNP-2006-Correspondence Others-(02-07-2012).pdf

968-DELNP-2006-Correspondence Others-(03-02-2012).pdf

968-DELNP-2006-Correspondence Others-(29-02-2012)-.pdf

968-DELNP-2006-Correspondence Others-(29-02-2012).pdf

968-delnp-2006-Correspondence Others-(29-05-2012).pdf

968-delnp-2006-correspondence-others.pdf

968-delnp-2006-description (complete).pdf

968-DELNP-2006-Drawings-(02-07-2012).pdf

968-delnp-2006-drawings.pdf

968-DELNP-2006-Form-1-(02-07-2012).pdf

968-delnp-2006-form-1.pdf

968-DELNP-2006-Form-2-(02-07-2012).pdf

968-delnp-2006-form-2.pdf

968-DELNP-2006-Form-3-(02-07-2012).pdf

968-delnp-2006-form-3.pdf

968-delnp-2006-form-5.pdf

968-DELNP-2006-GPA-(02-07-2012).pdf

968-delnp-2006-gpa.pdf

968-delnp-2006-pct-210.pdf

968-DELNP-2006-Petition-137-(02-07-2012).pdf