FR2530752A1 - TORSION VIBRATION DAMPER, PARTICULARLY FOR TRANSMISSIONS OF MOTOR VEHICLES EQUIPPED WITH A TORQUE CONVERTER - Google Patents

Abstract

TORSIONAL VIBRATION DAMPER COMPRISING A DRIVING DISC AND A DRIVING DISC, HOUSING BETWEEN COVERS WHICH ARE AXIALLY SOLIDARITY AND IN ROTATION, MOBILE IN THE TANGENTIAL SENSE OF ONE IN RELATION TO THE OTHER AND EACH IN RELATION TO THE COVERS, AND TAKING INDEPENDENTLY SUPPORT ON THESE LATEST IN THE TANGENTIAL SENSE, EACH BY A GROUP OF DAMPER SPRINGS ACTING IN THE TANGENTIAL SENSE AND HOUSED on the one hand in NOTCHINGS DISTRIBUTED TO THE PERIPHERY OF THE COVERS AND on the other hand IN THE LEADING DISC OR THE DRIVEN DISK. IN ADDITION TO THE DAMPER SPRINGS, A FRICTION STAGE IS PROVIDED ON the one hand between the lead disc 12 and the covers 13, 14, and on the other hand between the latter and the lead disc 30, and act upon the appearance of RELATIVE MOVEMENTS BETWEEN SAID DISCS.

Description

The present invention relates to a torsional vibration damper,

  intended in particular for motor vehicle transmissions equipped with a torque converter, and comprising a driving disc and a driven disc housed between covers, which are axially and rotationally fixed, movable in the tangential direction, one by relation to each other and each in relation to the lids,

  and taking independent support on these in the

  gential, each with a group of damping springs acting in

  the tangential direction and housed on the one hand in notches distributed around the periphery of the covers and on the other hand in the driving disk

or the led record.

  Torsional vibration dampers of this type are for example required in motor vehicle transmissions equipped with an automatic transmission in connection with a converter of

  torque or a hydraulic clutch to compensate for irregularities

  rities, jerks, etc., and delete in particular, as soon as they appear

  tion, periodic excitations of torsional vibrations.

  The patent application of the Federal Republic of Germany published under No. 30 47 039 discloses a torsional vibration damper of the aforementioned type, intended for motor vehicle transmissions equipped with a torque converter, comprising two stages of friction and wherein a drive disk, driven by the converter, and a drive disk secured to a rotation of a shaft

  outlets are housed between lids, on which they take

  With the aid of damping springs acting in the tangential direction, relatively large relative movements between the driving disk and the covers on the one hand, and between the latter and the driven disk, on the other hand, being made by distributed spring sets. for each step at the periphery and each having several damping springs connected in series between the spring

  cushion of each game, each housed in a recess

  tial, radial stages are arranged, which, for a step, are connected either to the driving disk or to the lids

  framing the latter, and in the second stage, are mobile

  3 _ gentially in order to allow the transmission of a torque of the disk leading to the driven disk, as well as the relative movements damped between these disks and the covers, and consequently also

between the drives leading and driven.

  The aim of the invention is however to provide a vibration damper

  However, in particular, a more efficient suppression of periodic torsional vibration excitations is provided. According to an essential characteristic of the invention, a friction step is provided on the one hand between the driving disc and the covers, and on the other hand between the latter and the driven disk, and acts during the appearance of relative movements

between said disks.

  In the case of the invention, it is therefore a question of superimposing on the vibration damping produced by the damping springs a damping effect resulting from the friction steps, which naturally leads to a rapid decrease of the vibration excitations. and as a result of the suppression of torsional vibrations

at the moment of their appearance.

  According to another characteristic of the invention, the damping springs of each group are connected in parallel, but the

  groups are mounted in series, so that the appearance of a debate-

  angle between the driving disc and the driven disc produces a joint action of the groups of springs assigned to these two discs The elastic characteristic resulting from a series assembly

  with a lower slope than the characteristics of the

  individual spells mounted in series, a significant angular movement is thus feasible only for low torsional moments It should be that the damping springs of each group all have the same stiffness According to another characteristic of the invention,

  damping springs of various groups, on the other hand, can

feel a different stiffness.

  An appropriate dimensioning of the stroke and the stiffness of the damping springs of the various groups makes it possible to obtain a plot of the characteristic different from that of the initial range, starting from a predetermined angular displacement between the driving disk and the driven disk. The result is obtained by suppressing the joint action of the damping springs of the various groups when a predetermined angular displacement is reached. The joint action of the damping springs of the various groups, working in series over an initial range of angular deflection, can for example be omitted. by completely compressing the damping springs of a group after a predetermined range of angular deflection,

  so that only the damping springs of the second group

  make a relative movement between the corresponding disk and the covers, and consequently an increase in the angle of rotation between the driven disk and the driving disk. It goes without saying that only the characteristic of the damping springs still participating in

  angular deflection occurs for the locking of

  weavers of a group before this second range of angular deflection

  According to another characteristic of the invention, the relative mobility of the driving disc and / or the driven disc relative to the covers is limited to a predetermined angular displacement by a stop acting in the tangential direction, the intervent of said stop in the corresponding direction of rotation producing a rigid connection in rotation between the corresponding disc and the covers, and consequently the disconnection of the damping springs acting

between said means.

  When, on the other hand, the damping springs of at least one group are bandaged, according to another characteristic of the invention, it is possible to achieve decreasing characteristics. The damping springs of a group, with no or low tire, act

  then only on an initial range of angular deflection and deter-

  the variation of the rotation torque as a function of the angular deflection and of their own stiffness As soon as the force exerted by the damping springs of this group reaches, as a result of the

  compression, the bandage force of the damping springs of the

  The following are the springs of the two groups acting in series and the achievable angular deflection is the sum of the deflections

  angles produced on the various groups of springs.

  In this way, the rotational torque as a function of the angular displacement has a flatter course, so that the characteristic of the assembly over the range of angular deflection, for which the damping springs of the two groups exert a joint action, shows a decreasing pattern. relative to the initial range of angular deflection, on which act only the unbuffered damping springs of the aforementioned first group. According to another characteristic of the invention, the torsional vibration damper can also be equipped with a third damper group, by providing a group of damping springs which act only when a predetermined angular displacement is reached between the driving disk and the lids or between these and the driven disk, so that these damping springs

  additional contributions are being made in parallel with the

  weavers of the still active group, when the predetermined angular displacement is reached, which obviously results in a significant increase in the torsional stiffness and consequently a higher slope

  the torque characteristic as a function of angular deflection.

  According to another characteristic of the invention, the damping springs

  weavers of the group acting only when a predetermined angular clearance is reached are integral in rotation with the clusters and housed in arched notches, located on the driving disk

  or the driven disk extending from both sides in the tangential direction

  over a predetermined distance beyond the length of the

  aforementioned damping spells of said group Considering the housing in peripheral notches exceeding on both sides the length of the springs in the tangential direction, said springs

  dampers do not reach the edges delimiting the longitudinal notches

  curved in the peripheral direction after the crossing

  games between their front faces and said edges, which

  constitute then stops for the springs, these last

  coming in parallel with the damping springs of the still active group. According to another characteristic of the invention, a step of

  load friction is provided between the driving disc and the

  and / or between the latter and the driven disk, and acts solely

  when a predetermined angular deflection is reached; said friction step can be mounted with limited axial mobility between the discs having a relative mobility in the tangential direction and in frictionless rotation at a predetermined peripheral angle with respect to one of said discs, the friction disc being, after the driving on the rotation range without friction, secured in rotation with the above-mentioned disc,

the led record for example.

  According to another characteristic of the invention, a friction step can be provided directly between the driving disk and the driven disk, so that the appearance of a relative rotation involves the direct friction between the driving and driven disks, in addition friction influences between the driving disk and the lid on the one hand, and between these and the disk

led on the other hand.

  In one embodiment of the torsional vibration damper according to the invention, each friction step comprises a friction washer applied on at least one surface of

  friction of the discs with tangential mobility relative to

  In at least one friction step, this friction washer can be applied by a limited axial mobility presser plate to the friction surface of one of the relative tangential mobility disks, while the pressure plate is loaded by the force of springs and rotatably mounted on the second of the disks exerting a joint action in the friction step A Belleville spring can apply each plate

  pressure or friction disc.

  Other features and advantages of the invention will be

  better understood using the detailed description below of

  several embodiments and accompanying drawings on the

  which: Figure 1 is the partial front elevation of a first embodiment of a torsional vibration damper according to the invention three stages of damping; Figure 2 is the sectional elevation of the torsional vibration damper along the axis II-II of Figure 1; FIG. 3 shows the characteristics of the rotational torque as a function of the angular displacement for the traction and thrust sections; Figure 4 is the elevation, similar to Figure 1, of a second embodiment of a torsional vibration damper also of three steps; Figure 5 is the section of the torsional vibration damper along the axis V-V of Figure 4; FIG. 6 shows the characteristics, as in FIG. 3, of the torsional vibration damper according to FIGS. 4 and 5; FIG. 7 is the elevation, similar to FIGS. 1 and 4, of a

  another embodiment of a vibration damper of tor-

  according to the invention, but in two steps; Figure 8 is the sectional elevation of the torsional vibration damper along the axis VIII-VIII of Figure 7; and FIG. 9, similar to FIG. 6, shows the characteristic

  of the embodiment according to FIGS. 7 and 8.

  The torsional vibration damper 10, shown in FIGS. 1 and 2, comprises a driving disc 12 integral in rotation

  it does not intervene in the context of the invention.

  tion and simply shown in phantom The driving disk is dis-

  placed between lids 13, 14 having an axial spacing and integral in rotation and axially The lids are connected by spacing columns 15, riveted on them, distributed on their periphery near the outer edges and through bent 16 elbowed holes of the driving disk 12 The spacing columns 15 can move along the length

  periphery of said elongate holes 16 and thereby produce rotational

  relative to the covers 13, 14 and the driving disk 12, according to

the subsequent description.

  Shock absorber springs 20 are housed, with tangential offset

  relative to the oblong holes 16 traversed by the spacing columns 15, in tangential notches 17, 18, 19 distributed at the periphery of the covers 13, 14 on the one hand and the drive disc 12 on the other hand, which take thus mutually support in the tangential direction The damping springs 20 are maintained as follows in the windows-shaped peripheral indentations of the drive disk 12 and the covers 13, 14 The outer edges of the peripheral notches 17, 18 of the covers are folded outwards and at least partially cover the damping springs Friction washers 22, 23 are disposed on either side of the drive disk, radially inward relative to the damping springs; they constitute a first step of friction and, with the damping spring distributed around the periphery, a first damping step The friction washer 23 exerts a direct joint action with an internal friction surface of the inner cover 14, while the second washer friction 22 is applied to the disc driving by a spring Belleville 25, bearing on the lid 13

  outside, and a pressure plate 24 integral in rotation with

  13, 14, but having a limited axial mobility with respect to the latter The pressure plate 24 comprises in the vicinity of the spacer 15, solidarisant the covers in rotation and axially, radial portions 26 outwardly and partially surrounding the standoffs, as shown

Figure 1.

  A driven disk 30 is housed between the covers 13, 14, radially

  inside the driving disk 12 and coaxially with the latter; said disc 30 has on the hub side an internal toothing 32

  which secures it in rotation with external teeth 33 corres-

  of an output shaft 34 simply sketched in FIG.

  Damping springs 40, also acting in the tan-

  are housed in an inner ring of indentations 36, 37,

  38 distributed on the periphery and corresponding in

  keys 13, 14 on the one hand and the driven disk 30 on the other hand; these-re-

  Spells are held in position by the outer folded edges of the peripheral indentations of the covers. The driven disc 30 and the covers 13, 14 resiliently support each other in the tangential direction through these internal shock-absorbing springs. way that in the case of the driving disc, friction washers 42, 43 are arranged

  on either side of the edge of the driven disk, in the vicinity of the hub.

  While the friction washer 42 acts directly between the driven disc and a corresponding friction surface of the front cover 13, the friction washer 43 is applied to the other face of the driven disc 30 by a presser plate 44 with axial mobility.

  limited and rotational solidarity lids The force of application

  cation is produced by a Belleville spring 45, which is supported on a friction disc in charge 48, described below in connection with

  with a third step of damping.

  The friction disk 48 is disposed coaxially with the driven disk 30 and with limited axial mobility between the latter

  and the inner cover 14 In the vicinity of the peripheral notches

  containing the damping springs 40 of the second damping stage, in the driven disk 30 and the covers 13, 14,

  the loaded friction disc 48 also includes samples

  peripheral cranes 49, whose tangential length is however greater than that of the peripheral notches of the driven disk and

  lids, so that the friction disc under load

  some tangential mobility with respect to

  and the disc, without the damping springs 40 are applied on the limits of these peripheral notches 49 in the tangential direction. This friction disc 48 is a third damping stage with two damping springs 50 These two damping springs are housed symmetrically between

  several damping springs 40 of the second damping step

  in other peripheral notches 51, 52 of the lids

  13, 14 and pass through a peripheral notch 53, 54 correspon-

  of the driven disk 30 and the loaded friction disk 48.

  The peripheral indentations 53, 54 of the driven disc 30 and the friction disc in charge 48 have a length in the tangential direction greater than the corresponding length of the damping springs 50, which do not apply to the delimitations of the

  peripheral notches 53 of the driven disk 30 after a rota-

  predetermined configuration of the latter with respect to the covers 13, 14,

  and therefore act only after the appearance of the angular deflection

predetermined above.

  A friction washer 56 is disposed between the load friction dies 48 and an internal friction surface of the inner cover 14 In view of the pressure plate 44 belonging to the second friction step and solidly rotated with the lids by tongues 4: 6 axial, which pass through peripheral notches and engage with safety in shape in the inner cover 14, the friction disc in charge 48 is applied to the friction washer 56 and the latter on the corresponding friction surface of the cover In contrast, the friction disk 48 rotates freely through

  compared to the driven disk 30, over a predetermined range of perimeter angle

  pheric; axial tongues 57 of the friction disc under load engage in the peripheral indentations 53 of the driven disc 30,

  extending on either side of the damping springs 50, arriving

  wind on abutments after a predetermined rotation of the friction disk in load relative to the driven disk, then rotate in solidarity the friction disk in charge and the disk driven in

  the direction of rotation considered The damping springs 50 constitute

  kill, with the friction disc in charge 48 and the friction washer

  56 between the latter and the corresponding friction surface.

  the inner cover 14, the third stage of damping.

  When the torsional vibration damper 10 is in use, the application of a torque by the driving part 11 to the driving disk 12

  produces a rotation on the one hand between the driving disk and the cover

  13, 14 and secondly between them and the driven disk 30, which is integral in rotation with the output shaft 34 The spring

  damper 20 and 40 of 7 the first and the second damping stage

  which are mounted without a bandage, then act in series with

  low stiffness The flat pattern of characteristic 60 of the dia-

  FIG. 3 illustrates this point. The maximum rotation obviously occurs in the zone of the damping step whose damping springs have the minimum stiffness. In the case considered, this is the damping step which acts between the drive disk 12 and the covers 13, 14 and comprises the damping springs 20 As soon as the springs 20 of this step have, as a result of the rotation of the drive disk 12 relative to the covers 13, 14, undergone a compression such that the spacing columns 15, solidarisant the two covers in rotation and axially, are applied on the ends of the bent elongated holes 16 of the driving disk, the damping springs of the first stage are eliminated and only the damping springs of the second stage

  On the diagram in Figure 3, the first step of amor-

  The range of the angular deflection range from 0 to 230 and, after the elimination of the first damping stage, only a relative movement between the driven disk 30 and the covers 13, 14 occurs for an angular displacement of between 23 and 25.degree. 38, only the damping springs 40 acting, which leads to a higher slope of the characteristic 61 in the sector of the second damping stage For an angular deflection of 38

  between the driving disk 12 and the driven disk 30, the damping springs

  weavers 50 of the third stage of depreciation apply on

  delimitations in the tangential direction of the peripheral notches

  windows 53 of the driven disk, so that the damping springs 50 of the third step act in parallel

  with the damping springs 40 of the second damping step.

  This parallel connection of the damping springs 40 of the second stage and the damping springs 50 of the third stage produces

  obviously a steep slope of characteristic 62, which

  rope to the characteristic 61 of the second damping step for an angular deflection of 38 and acts until the total blocking of the damping springs of the second and third stages,

  for an angular clearance of 42.

  In addition to the previously described intervention of damping springs

  When angular movements occur between the driving disk 12 and the covers on the one hand and between the latter and the driven disk on the other hand, the friction steps assigned to each damping step act according to the movements

  relative to the driving disk and the driven disk relative to the covers.

  Thus, in the sector of the first stage of depreciation,

  With relatively soft damping springs, the

  initial rotation is accompanied in particular by a rela-

  between the driving discs 12 and the covers 13, 14, so that a friction work is provided in particular in the area of the friction washers 22, 23 When a deflection angle

  predetermined distance is reached between the driving disk 12 and the covers

  13, 14, the spacers 15 connecting the covers are applied to the ends of the bent elongated holes 16 and therefore prohibit a new relative movement between the drive disc 12 and the covers; the friction work produced by

  the continuation of the angular deflections is first provided only

  in the area of the two friction washers 42, 43

  killing the second friction step The friction disc in charge 48 is, as during the rotation of the driving disc 12

  relative to the covers 13, 14, at rest with respect to the covers

  key until the axial tongues 57, engaging in the peripheral notch 53, reach stops within the latter, thus limiting the rotational mobility of the friction disc under load relative to the driven disk 30 When the tongues 57 of the friction disc under load reach the abovementioned abutments, the third friction step acts as

  follows: the friction disc in charge, that the friction washer

  56 frictionally connects to a corresponding friction surface

  of the inner lid 15, is rotated relative to

  port to said inner cover The friction work provided in the vicinity of the friction washer 56 of the third friction step is superimposed as a result of the friction work produced in the area of the second friction step. As can be seen from the traction side of the diagram in Figure 3, that works

  equal friction must be provided when the rotational torques are

  decrease with a corresponding return of the relative mobility discs in the tangential direction The conditions valid for the pushing side, simply sketched, are in principle identical

  to those valid-for the pulling side of the diagram.

  The embodiment according to FIGS. 4 and 5 is also a three-stage torsional vibration damper, whose parts identical to those of FIGS. 1 and 2 have the same references,

but increased by 100.

  A driving part 111, simply shown in phantom, applies a torque to a driving disk 112, housed between lids 113, 114 integral in rotation and axially. The transmission of the torque to a not shown output shaft is ensured by a disk. conducted

  , coaxial with the driving disk 112, extending radially towards the

  in relation to the latter and also housed between the

  instead of being fitted on the hub side with a cylindrical toothing

  a simple bit 132, interacting with a combined toothing of the output shaft, the driven disk may comprise in the vicinity of the

  hub a veil 131 having a corresponding groove 132 '.

  As in the first embodiment, damping springs

  weavers 120, 140 are housed in peripheral notches 117, 118, 119 and 136, 137, 138 corresponding to the drive disk 112 and covers 113, 114 on the one hand, and driven disk 130, and

  lids on the other hand, the disk driving as the driven disk first

  tangential support on the lids by means of

  In contrast to the case of the first embodiment, the first damping step is instead assigned to the driven disk 130 and the second step to the driving disk.

  112 Four springs 140 in total of the first stage of depreciation

  They are then housed in the peripheral indentations 136, 137, 138 distributed on the covers 113, 114 and the driven disc, while three damping springs 120 of the second stage are arranged in each of the two halves, in the vicinity of the disc. 112 damping springs 150 of a third stage, housed in peripheral slots 153 in the form of windows of the driving disk 112, are arranged between the groups each comprising three damping springs 120 of the second stage, in

  peripheral notches 151, 152 corresponding to the

  113, 114 These bent peripheral notches 153 of the drive disc 112 extend well beyond the length of the damping springs 150 of the third step, so that they act in parallel with the damping springs 120 of the second step only when the driving disk 112 has undergone, after compression damping springs 120 of the second stage, a compression such that the damping springs 150 of the third

  apply to the tangential delimitations of the samples.

  Peripheral crusts 153 bowed from the driving disk.

  As in the first embodiment, the damping springs of the first and second damping stages are connected in series during the initial phase of a rotation between

  the driving and driven discs, so that the rotation of said discs

  in charge is opposed to the total resultant of this series assembly.

  The common action range of the damping springs of the first and second stages extends to an angular deflection of

  320 in this embodiment, as shown in the characterization

  160 of FIG. 6 The relatively soft damping springs of the first stage undergo a predominant compression

  until the spacing columns 115, movable tangential-

  in the bent 116 oblong holes of the driven disk 130, movable

  tangentially and solidarisant the lids 113, 114 rotating

  and axially, reach the ends of said oblong holes and thus block the driven disk relative to the covers in the direction of rotation considered The first step is thus stopped and new angular deflections can appear between the drive disc 112 and the covers Given the previously described elimination of damping springs 140 of the first step, only the damping springs 120 of the second step oppose an angular deflection of greater than about 32, until the damping springs 150 of the third step occur in parallel with the damping springs 120 of the second step, when an angular clearance of about 38 is reached The characteristic 161 of the second step is therefore determined by the only stiffness of the damping springs 120 of the second step on the beach angle of rotation between 320 and 380 The characteristic 162 of the t third step has against a steep slope, imposed by the parallel connection of the damping springs 120 and 150 of the second and third

  stage, and of the resultant equal to the sum of the elastic constants

of the various jurisdictions.

  In the second embodiment too, friction is

  superimposed on the action of the springs of the various damping stages.

  Unlike the case of the first embodiment, only a friction washer 122 is in a radial overlap area between the drive disk 112 and the driven disk 130; a pressure plate 124, integral in rotation with the driven disk, but movable axially with respect to the latter, applied

  however, said washer 122 on the drive disk 112 through

  a spring Belleville 125 acting between said plate 124 and the driven disk 130 It is also possible to perform the assembly so that a friction acts in the vicinity of its outer edge, between the drive disc and the covers, and near the hub area, between the driven disk and the lid, when

  said disks are rotated relative to the lid.

  Unlike the case of the first embodiment, this second embodiment has no additional friction disc acting only during the third step

  damping; it is also possible that the rubbing action

  early or late on the intervention of the damping springs of the third step, depending on the limitation of its mobility in rotation with respect to the driven disk, so as to

  produce a "driven friction".

  The third embodiment illustrated in FIGS. 7 and 8 is a two-stage vibration damper, in which

  parts identical to those of the preceding embodiments

  dentes have the same references, but again increased by 100. In this embodiment also, the load is applied by a driving part 211 simply represented in dots and dashes, using a drive disc 212 again housed between lids

  213, 214 integral in rotation and axially Radially to the in-

  inside the driving disk 212, a driven disk 230 equipped with a hub 231 is housed between the lids and secured in rotation, in a manner not of interest to the invention, with an output shaft 234 simply indicated in dots and dashes As in the second embodiment, the damping springs 240 of the first step are housed between the driven disk 230 and the covers 213,

  214, in peripheral indentations 236, 237, 238 corresponding to

  21 of the lids 213, 214 and the disc 230 The possibility of rotation of the driven disc relative to the lids is limited

  by the spacing columns 215, which solidarize the necks

  rotation and axially, through bent oblong holes 216 of the driven disk and are applied to the peripheral edges of said oblong holes when a predetermined rotation angle is reached between the driven disk 230 and the covers 213, 214, a solidarity connection in rotation then appearing between

  the driven disc and the covers in the direction of rotation considered

  deregulated, and thus eliminating the damping springs 240 of the first

  The damping springs 220 of the second damping stage act between the driving disc 212 and the covers 213, 214 as in the embodiment according to FIGS. 4 and 5, but are, unlike the latter, mounted without a bandage. . As a result of the tire damping spring 220 of the second damping step, it first appears under load a rotation between the driven disk 230 and the covers 213, 214, until the elastic force of damping springs 240 of the first stage achieve by compression the bandage force

  damping springs 220 of the second stage Only the res-

  damping spells 240 of the first step thus acting during the initial phase of rotation, the pace of the characteristic 260

  in FIG. 9 results, in the range between 0 and 3

  However, only the stiffness of the damping springs 240 of said step increases the angular movement between the drive disk 212 and the driven disk 230, the damping springs 220

  the second stage intervene in series with the

  weaver 240 of the first damping stage, so that the resultant of the series connection acts The characteristic resulting from the series assembly having a lower slope than the individual characteristics of the damping springs 220, 240 of the two stages, the angular deflection s extending over an angle of rotation of about 30 is determined by the lower slope of characteristic 261 of FIG.

  approximately in the exemplary embodiment described the use of res-

  damping spells bandaged in one of the damping stages

  thus makes it possible to achieve a decreasing characteristic.

  The series assembly of the damping springs of the first

  and the second step is deleted, when the angular

  the gap increases between the drive disc 212 and the covers 213, 214 by stops acting therebetween for an angle

  around 14, a rigid connection in rotation

  then falling between the driving disc and the covers in the direction of rotation considered After this elimination of spring

  shock absorber 220 of the second stage, a new angular deflection

  can only occur against the action of the

  weavers 240 of the first step acting alone on the initial range of rotation, until the stops acting between the covers and the driven disk are applied and thus rigidly connect in rotation the led disk to the lids, in the direction of rotation considered These stops are constituted by spacing columns 215, which secure the lids 213, 214 in rotation and axially, and through the bent elongated holes 216 of the driven disk 230 In Figure 8, the characteristic section 262 steep slope , connecting to the average stretch

  261 at low slope, represents the operating state after

  cage rotational mobility of the disc leading relative to the lids.

  In this embodiment too, a friction washer

  222 is disposed in a lap region between the disk

  leading 212 and the driven disk-230, as well as a friction washer

  223 between the driving disk and the inner lid 214.

  Another friction washer 242 is located radially in the

  interior of the damping springs 240 of the first step, resting on the driven disk 230 a pressure plate 224, integral in rotation with the outer cover, applied by means of a Belleville spring 245 It is seen that a rotation of the driven disk 230 relative to the covers 213, 214 produces friction in the region of the friction washer 242 of the driven disc, on the hub side, as well as in the area of the friction washer 222 between the driven disc 230 and the drive disc 212 La second friction step is produced, upon a rotation of the drive disc 212 relative to the covers 213, 214, by friction in the area of the friction washer 223 acting between the drive disc and the rear cover 214; it is the same, for an angular displacement between the driving disc and the driven disc, in the area of the friction washer 222 acting between these two discs In the sector of the section 262 of the characteristic with steep slope, between about 14 and 15, 50, a friction occurs in the area of the friction washer 222, housed between the drive disc and the driven disc, and in the area of the friction washer 242 of the led 8, in the vicinity of the hub is seen that a friction is superimposed on the action of the damping springs

  on all operating areas of the vibration damper

twisting.

  Of course, various modifications may be made by those skilled in the art to the principle and to the devices which have just been described solely by way of nonlimiting examples, without

* depart from the scope of the invention.

Claims (15)

claims   1 Torsional vibration damper, especially for   to motor vehicle transmissions equipped with a conver-   torque weaver, and comprising a driving disk and a driven disk housed between lids which are secured axially and in rotation, movable in the tangential direction with respect to   the other and each in relation to the lids, and taking   the latter are supported by means of a group of damping springs acting in the tangential direction and housed on the one hand in notches distributed around the periphery of the covers and on the other hand in the driving disk or the driven disc. said damper being characterized in that a friction step is provided on the one hand between the driving disc (12, 112, 212) and the covers (13, 14; 113, 114; 213, 214), and between them and the driven disk (30, 130, 230), and acts   when relative movements occur between said disks.   2 torsional vibration damper according to claim 1, characterized in that the damping springs (20, 40, 50, 120, 150, 220, 240) of each group are connected in parallel,   but the groups are mounted in series.   3 Torsional vibration damper according to one of the claims   1 or 2, characterized in that the damping springs (20, 40, 50, 120, 140, 150, 220, 240) of each group have the same stiffness.   4 Torsional vibration damper according to any of the   1 to 3, characterized in that the damping springs   (20, 40, 50, 120, 140, 150, 220, 240) of various feel a different stiffness.   Torsional vibration damper according to any one of   claims 1 to 4, characterized in that the relative mobility of the   driving disk (12, 112, 212) and / or the driven disk (30, 130, 23) relative to the covers (13, 14; 113, 114, 213, 214) is limited to a predetermined angular deflection by at least one stop   (15, 16; 115, 116; 215, 216) acting in the tangential direction.   Torsional vibration damper according to claim 5, characterized in that the abutment (15, 115, 215) is integral with the covers and engages in a bent notch (16, 116, 216) extending over a predetermined peripheral angle of the disc   driving (12, 112, 212) and / or driven disk (30, 130, 230).   7 torsion vibration damper according to claim 6, characterized in that the stop is constituted by a spacer (15, 115, 215) connecting the covers and axially through the arched notch (16, 116, 216) of the disc leading   (12, 112, 212) or the driven disk (30, 130, 230).   8 Torsional vibration damper according to any one of   Claims 1 to 7, characterized in that the springs   dampers (20, 120, 220) or (40, 140, 240) of at least one group are bandaged.   9 Torsional vibration damper according to any one of   Claims 1 to 8, characterized by a group of springs   dampers (50, 150) acting only when a predetermined angular deflection is reached between the drive disk (12, 112) and the covers (13, 14, 113, 114) or between the latter and the driven disc (30, 130).   Torsional vibration damper according to claim 9, characterized in that the damping springs (50, 150) of the group acting only after a predetermined angular deflection are integral in rotation with the covers (13, 14; 113, 114) and accommodated in curved indentations (53, 153) on the drive disc (12, 112) or the driven disc (30, 130) and extending tangentially on both sides for a predetermined distance   beyond the length of the damping springs of said group.   11 Torsional vibration damper according to any one of   Claims 1 to 10, characterized in that a step of rubbing   load is provided between the drive disc (12) and the covers and / or between these and the driven disc (30) and acts   only when a predetermined angular deflection is reached.   12 Torsional vibration damper according to any one of   Claims 1 to 11, characterized by a friction step   provided directly between the driving disk (112, 212) and the disk led (130, 230).   13 Torsional vibration damper according to any of the   Claims 1 to 12, characterized in that each step of rubbing   element has a friction washer (22, 23, 42, 43, 56, 122, 222, 223, 242) applied to at least one friction surface.   relatively tangential mobility discs.   Torsional vibration damper according to claim 13, characterized in that in at least one friction step the friction ring is applied by a pressure plate (22,   44, 48; 124; 244) - with limited axial mobility on the friction surface   of one of the relatively tangential mobility discs, while the pressure plate is loaded by the spring force and rotatably mounted on the second of the discs exerting   a combined action in the friction step.   Torsional vibration damper according to claims 11   and 13, characterized in that the friction step in charge comprises   carries a friction disc (48) movable axially between the relative tangential mobility discs and rotatably mounted without friction on a predetermined peripheral angle with respect to   one of said discs, but secured in rotation with said disc   only after crossing the predetermined peripheral angle   in the direction of rotation considered.   16 Torsional vibration damper according to one of the claims   14 or 15, characterized in that the application of each pressure plate and the friction disk is provided by a   Belleville spring (25, 45; 125; 245).