FR2518203A1 - Shock absorbing vehicle flywheel - has two flexible coupled discs capable of limited relative movement with opposed abutting stops - Google Patents

Abstract

The flywheel is firmly fixed to an internal combustion engine output shaft and is then firmly fixed to the input shaft (12) of a gearbox, via a clutch (6). Two concentric discs (2,4) can turn relative to each other, limited by one or a series of stops (20). The discs are connected by flexible parts (17). The stop slides on one disc (4) and is returned towards the centre. The other disc also has a stop and an opposed high speed stop, formed by shoulders, which blocks the stop on the first disc.

Description

The invention relates to steering wheels intended

  born to be made integral with the output shaft of a

  internal combustion engine and to be coupled to the rear

  entry of a gearbox via a friction disc clutch, in particular in a motor vehicle, flywheels of the type comprising two

  concentric plates which can rotate one relative

  port to the other to a limited extent by pull stop and retro means and which are connected in

  IO rotation by elastic members.

  To avoid the use of a heavy flywheel whose inertia is sufficient to filter the angular vibrations of the motor shaft, mainly when the latter has a small number of cylinders and idles,

  I 5 it is customary to provide an oscillation damping device

angular lations.

  If this device is incorporated in the hub of the friction disc, the disc is weighed down, especially if the damping device is arranged to act in a variable manner according to various parameters such as the speed of rotation of the engine. Consequently, the disc being generally integral in rotation of the input shaft of the gearbox, its high inertia makes it difficult to change gear ratios of this gearbox and requires excessive work on the synchronizers used

  to make these gear changes.

  It is known to remedy this drawback by means of flywheels of the aforementioned type, that is to say by placing the damping device not in the hub of the disc but in the flywheel This comprises

  then essentially two circular or annular trays

  laires which can rotate relative to each other about their common axis by means of a bearing,

  and which are connected in rotation by elastic members.

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  One of the plates is anchored on the motor shaft, and the other, which is the receiving plate, has an annular friction surface capable of cooperating with the

  clutch disc The elastic members, which are -

  generally springs, the ends of which are respectively connected to the two plates, allow the latter to oscillate in rotation on either side of a relative mean position, with respect to which the angular difference between the two plates is limited by IO stop means, called "pulling" in the direction where the motor plate drives the receiver plate, and "

retro "the other way around.

  When the engine is idling, do not

  putting no noticeable torque on the shaft of the 5-speed gearbox, the angular vibrations of which it is the object are damped in part by the relatively light flywheel, and in part by the springs which allow angular oscillations between the two When the flywheel transmits a significant engine torque to the shaft of the gearbox, the pull stop means are

  in action; and in motor brake phase, the trans-

  put being inverted as well as the angular distance between the plates, it is the retro stop means which are in action As soon as the stop means are in action, the coupling between the two plates is positive; the springs do not intervene in the transmission of the torque, which is not a disadvantage since then the engine turns at a sufficient speed so that the

  steering wheel alone, even light, filters vibrations properly

  angular positions of the motor shaft But the reversals

  the transmitted torque causes, on each entry into action of the abutment means, alternately of draw and retro, jerks due to the inversion of said angular difference between the plates; such jolts are harmful to the endurance of the transmission organs of the

  torque and, when the device equips a motor vehicle

  mobile, are unpleasant to feel by its occupants.

  The object of the invention is to remedy these drawbacks by providing a vibration-damping flywheel which is relatively light and which ensures

  smooth transmission during torque reversals.

  To this end, it relates to a steering wheel of the aforementioned type, characterized in that the stop means IO comprise at the imins a lock mounted sliding radially on a plate and resiliently biased towards the center of this plate, and in that the other plate carries a pull stop and a high speed retro stop located opposite the radially outer part of the pull stop and at a distance therefrom

  I 5 slightly greater than the corresponding dimension of the lock.

  According to advantageous features of the invention: said other tray also carries a

  low speed retro stop located next to the ra-

  internal dialeneent of the pulling stop and more distant from it than the high speed retro stop; the lock comprises a capsule guided by a stud integral with the first plate and containing

a centripetal return spring.

  An embodiment of a steering wheel according to the invention is described below, with reference to the accompanying drawings, in which: FIG. 1 is a view in axial section of a

  flywheel according to the invention, associated with a friction clutch

  partially presented, taken along line I-I in Fig 2; Fig 2 is a partial view of the steering wheel, taken in section along line II-II of Fig 1; and Fig 3 is a partial sectional view

  taken along line III-III of Fig 2 and correspond-

  in another mode of operation of the steering wheel.

  We see in the figures a flywheel 1 comprising an engine plate 2 fixed to the end of an output shaft 3 of an internal combustion engine, and a receiver plate 4 attached to the plate 2 and whose face turned on the opposite side of it cooperates with a

  friction disc 5 of a conventional clutch 6 This clutch

  ge essentially comprises a bell 7 fixed to the plate 4 by screws 8, a sliding plate 9 for clamping the

  disc 5 and a diaphragm spring 10 for clutch release

  IO die by a clutch release bearing 11 The disc 5 is solid

  Daire in rotation of a gearbox input shaft 12, one end of which can be seen carried by a bearing

13 at the end of the motor shaft 3.

  A bearing 14 for centering and abutment is

  I 5 interposed between the two plates 2 and 4 so that they

  set to rotate relative to each other around the central axis XX of the assembly and a flange 15 fixed to the periphery of the plate 2 ensures the axial maintenance of the plate 4 with the interposition of an annular lining 16 at low friction coefficient The bearing 14 is

  shown smooth, but alternatively it can be advanced

  taggedly replaced by a bearing with rings

  include axial stop means, which avoids the

  flange plate 15 Several helical springs 17 of

  traction arranged radially with their ends res-

  pectively attached to a lug 18 secured to the plate 2 and to a lug 19 secured to the plate 4 The springs 17 can tilt relative to their radial position,

  as shown in phantom in Fig 2, and allow

  thus feels a relative displacement in rotation of the two plates 2 and 4 on either side of an average position

  for which the springs 17 are oriented radially.

  Between the two trays are also dis-

  placed several locks 20 regularly distributed over the periphery of the steering wheel Each lock comprises a metal capsule 21 of parallelepiped shape elongated in the radial direction, open towards the plate 4 and which covers

  a guide pin 22 integral with the plate 4 and a res-

  helical compression spell 23; the spring 23 bears against the stud 22 and against an inner face

  24 of the capsule 21 so as to push it towards the center

be behind the wheel.

  Except at its radially inner end, IO the capsule 21 is externally coated with a sheath 25 of flexible plastic material intended to come into contact on the one hand with three faces or radial shoulders 26 to

  28 of the plate 2, these faces constituting lateral stops

  them for latch 20, and on the other hand with two shoulder-

  circular elements 29 of small diameter and 30 of large diameter also formed on the plate 2 and constituting

  stops for the latch 20 with respect to its centrifugal movements.

  The radial shoulders 26 and 27 face each other and start from the circular shoulder 30, which connects the external ends and forms part of a peripheral rim of the plate 2 The face 26, which constitutes the pulling stop, extends radially over a significant distance, while the face 27, which constitutes a high-speed retro stop, as will appear below, extends only opposite the external part of the face

  26 The circular shoulder 29 connects the inner end

  upper face 27 at the outer end of face 28, which constitutes a low-speed retro stop and is circumferentially opposite the inner part of face 26 Face 26 is covered with a lining 31 made of material flexible plastic This

  trim is spaced from face 27 by a slight distance

  rement greater than the circumferential dimension of the latch 20, while the distance between the face 28 and

  this trim is much larger.

  The motor plate 2 is here a carrier plate

  stop, but as a variant, it is clear that it is the receiving plate 4 which could be provided with the various stops

  26 to 30, the motor plate then carrying the latches 20.

  When stopped (Fig 2), the springs 17 are oriented radially and each latch 20 is substantially equidistant from the pulling stops 26 and retro bass

  speed 28, and is kept slightly away from the shoulder

  slightly circular 29 opposite by the centripetal thrust I O of the spring 23 on the face 24 of the capsule 21, which

  abuts on the radially outer face of the stud -22.

  When the engine is idling, its output shaft 3 is subject to significant vibrations around its axis of rotation, and the same is true for the I 5 plate 2 which is integral with it The latter rotates the plate 4 by means of the springs 17, which dampen the vibrations transmitted thanks to the

  angular oscillations between the two authorizing plates

  seized by the inclination of the springs 17 on either side

  of their radial average position These oscillations provo-

  quent a relative movement between each latch 20, linked in rotation to the plate-4 by the guide pin 22, and the various abutments integral with the plate 2 The mechanical characteristics of the springs 17 are such that each latch does not reach its pull stops 26

  or retro low speed 28 during this phase of ra-

  slowed down but moves along the circulating shoulder

re 29.

  As soon as the engine speed increases and its shaft 3, rotating in the direction of arrow F, transmits a significant engine torque to the plate 2, the latter

  rotates the plate 4 either by the res-

  spells 17, which stretch as much as possible in the inclined position, as shown in phantom in 17 A in Fig 2, but positively by pressing each pulling stop 26 against the corresponding latch 20, as visible in 20 A, in phantom , in Fig 2 Due to the speed of rotation, the lock is subjected to a centrifugal force and, against the spring 23, the capsule 21 slides radially on the guide pin 22 along the face 26 up to has drunk-

  ter against the circular shoulder 30, as shown

felt in Fig 3.

  When the transmitted torque reverses, the engine continuing to turn, in other words in the engine brake phase, the centrifugal force keeps the lock against the shoulder 30, and the plate 2 positively transmits the torque to the plate 4, this time oriented

  in the opposite direction to arrow F, by pressing his shoulder-

  radial 27 against the latch This shoulder 27 constitutes

  therefore moves a retro stop for notable speeds-

  ment greater than that of idling The distance between the lining 31 and the shoulder 27 being hardly more

  larger than the width of the latch 20, the angular travel

  the area between the two chainrings is negligible when the torque is reversed while the engine is running

  a speed significantly higher than that of idling.

  Such a torque reversal is therefore carried out smoothly, and the absence of relative angular oscillations between the two plates, the torque being transmitted positively without the intervention of the damping springs 17, is not a drawback because the flywheel inertia is enough to filter engine vibrations as soon as its speed is significantly higher than that of idling The flexibility of the linings 25 and 31 contributes to this filtration of

  vibrations in both directions of torque transmission '.

  If the engine speed decreases and becomes

  barely greater than that of idling, the force centri-

  fuge becomes insufficient to compress the spring 23, and the capsule 21 slides in the direction of the center of the

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  steering wheel and resumes initial radial position If at this low speed an engine brake is maintained, the torque transmitted by the plate 2 to the plate 4 being always oriented in the opposite direction to the arrow F, the radial face 28 comes into contact with the latch 20 as visible at 20 B in phantom in Fig 2 The face 28

  therefore constitutes a very low speed retro stop.

  It should be noted that if, under the effect of friction exerted on the lining 25, the latch 20 IO does not retract when the speed of the motor slows down, no inconvenience results. This withdrawal will occur later, during the next torque reversal, thanks to the small circumferential clearance provided between the lock

and the facing faces 26-31 and 27.

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Claims (8)

CLAIMS -   1. Steering wheel intended to be made integral with the output shaft (3) of an internal combustion engine and to be coupled to the input shaft (12) of a box   gears via a clutch (6) with   that friction, in particular in a motor vehicle, of the type comprising two concentric plates (2, 4) which can rotate relative to each other to a limited extent by means of pull-out stopper & et- de retro (20, 26 to 28) and which are connected in rotation by IO elastic members (17), this flywheel being characterized in that the stop means comprise at least one latch (20) mounted sliding radially on a plate   (4) and spring back towards the center of this plate   sheet, and in that the other plate (2) carries a stop for I 5 draw <26) and a retro-high speed stop (27) located opposite the radially outer part of the draw stop and at a distance of this light   greater than the corresponding dimension of the lock.   2. Steering wheel according to claim 1,   characterized in that said other plate (2) also carries   Lement a low speed retro stop (28) located in   gard of the radially inner part of the pulling stop (26) and further away from it than the retro stop high speed (27).   3 steering wheel according to claim 2, characterized in that the two backstops (27, 28) are constituted by two radial shoulders connected by a circular shoulder (29) forming a stop for the latch   (20) with respect to its centrifugal movements.   4 Lock according to any one of   claims 1 to 3, characterized in that the extremi   external tees of the high speed retro stop (27) and the pull stop (26) are connected by a circular shoulder (30) forming a stop for the latch   (20) with respect to its centrifugal movements.   5. Lock according to any one of   Claims 1 to 4, characterized in that the lock   (20) comprises a capsule (21) guided by a stud (22) integral with the first plate (4) and containing a spring centripetal recall (23).   6. Lock according to claim 5, characterized in that the capsule (21) has on its active faces IO an outer coating (25) of material flexible plastic.   7. Lock according to any one of   Claims 1 to 6, characterized in that the stopper   print (26) includes a coating (31) of material I 5 flexible plastic.   8. Lock according to any one of   Claims 1 to 7, characterized in that it comprises   several latches (20) regularly distributed over its periphery.