FR2840256A1 - VEHICLE SUSPENSION AND SUSPENSION THUS EQUIPPED - Google Patents

Abstract

The present invention relates to a suspension member for a vehicle capable of being subjected to compression during the relaxation of the vehicle suspension, comprising a spring element (2) elastically deformable during the compression stress and a deformable stop element (1) elastically only during a first compression stress phase. The stop element (1) and the spring element (2) are formed in one piece. The invention also relates to a suspension for a vehicle equipped with such a member. Particular application for suspensions of automotive type vehicles with stiffness characteristics corresponding to a stiffness curve capable of reproducing the criteria constituting a contract suspension.

Description

suspension (2) according to claim 24.

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  The present invention relates to a suspension member for a vehicle and

  a suspension for a vehicle fitted with such a member.

  The invention will find particular application in the field of

  manufacture and use of suspensions for motor vehicles.

  s Several types of wind suspension currently offered on the automotive market. In particular, conventional suspensions have linear flexibilities using stiffnesses which wind the result of a compromise between vertical comfort and

vehicle body management.

  To optimize this compromise, wind appeared from the anti-roll bars which, during the transfer of the masses stiffen the suspensions when cornering in order to reduce the

range of travel.

  The disadvantage of these bars lies in the fact that they link the wheels of a

  same train (front train or rear train) making them less independent.

  Another drawback is that this connection associated with additional friction degrades the filtration of the vehicle as well in vertical, lateral comfort

  (copying) only when going up in the whole direction.

  In addition, the mass transfers resulting from long iterative accelerations in diving or nose-up are always controlled by only the

  vertical stiffness of the suspensions.

  o Suspensions with variable flexibility have been proposed in an attempt to overcome the drawbacks mentioned. However, all these techniques still require the adoption of anti-roll bars with the drawbacks which result therefrom. Furthermore. for suspensions with variable flexibility, the compression stroke is reduced, and the relaxation stroke increased, which produces an elevation of the center

  s gravity of the vehicle in support, elevation detrimental to behavior.

  Smart suspensions have also been proposed, that is to say piloted by a central system incorporating electronic and computer means. However, such suspensions generally have a high cost,

and relative reliability.

  o Contractual quoted suspensions have also been proposed through this plaintiff. In particular, document WO-A-9104876 presents a suspension endowed with two distinct stiffnesses which are articulated around the position

vehicle statics.

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  This static position is predetermined and parameterized, and delimited by

  firstly the compression stroke, and secondly the relaxation stroke.

  Furthermore, the stiffness of the suspension in the relaxation stroke is greater than the stiffness of the suspension in the compression stroke according to a ratio of the order

s de1 a3.

  In other words, the stiffness in the compression stroke is relatively low and that in the relaxation stroke considerably higher. The resulting stiffness curve is of declining stiffness, which makes the contract suspension a system completely opposed to suspensions with linear flexibility or

o progressive.

  Still according to this previous technique, the point corresponding to the change between the two stiffnesses is located in the static position of the vehicle, that is to say correspond on the stroke of the suspension at the point of position of the

  vehicle when not subjected to any acceleration.

  This point, hereinafter referred to as a self-stabilizing reference point, creates a

  natural stabilization position for the vehicle.

  At this particular point, an intermediate connection flexibility is set up between the stiffness in the compression phase and that in

  phase of relaxation, and this to avoid too steep passage between the two.

  o This transition phase requiring flexible connection can be ensured by different technical solutions including that envisaged in WO-A 9104876 or also in document WO-A-9826193. In particular, an elastomeric stopper endowed with asymptotic flexibility can be implemented and it is by means of this stopper that the opposing spring will be put into action ensuring the additional stiffness necessary for the relaxation phase of this type of suspension. In current suspension arrangements using this technique, use is made on the one hand of a stop member performing the connection function, and

on the other hand has springs.

  o Although the various solutions proposed are technically satisfactory in terms of vehicle behavior than industrialization, it appeared to the applicant that even more economical solutions should be sought.

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  The present invention is part of this framework, and aims to provide a suspension member implantable in a vehicle suspension in particular

  automotive type to reduce manufacturing cost.

  Another advantage of the invention is to improve the ease of implantation in

  s the suspension, and this by reducing the number of component parts to be fitted.

  Another advantage of the invention is to ensure ease of adjustment of the

  stiffness and damping criteria through the adaptation of a single piece.

  Other objects and advantages will emerge during the description which follows

  of a preferred embodiment of the suspension member according to the invention and of

  o various embodiments of mounting in suspensions for vehicles.

  The present invention relates firstly to a suspension member for a vehicle capable of being subjected to compression stress, comprising a spring element elastically deformable during the compression stress and a stop element elastically deformable only during a first phase of compression stress. The stop element and the spring form element

in the same room.

  According to preferred variants, this suspension member is such that: The piece is made of elastomeric material, - The member is hollow for mounting around a rod, o - 11 has at least one passage along the member, on its outer surface, so that it can be mounted in a hydraulic shock absorber,

  - The wind passage (s) made up of axial grooves.

  The invention also relates to a suspension for vehicles. Wile is

  equipped with a member according to the invention.

  According to preferred embodiments, this suspension is such that:

  - The organ is mounted so that it is subjected to compression stress during

suspension relaxation phases.

  - It includes a hydraulic shock absorber in which the member is mounted.

  - It includes a movable floor which applies to one end of the body and has at least one fluid passage valve, to generate

  additional cushioning during deformation of the organ.

  - the organ is placed in opposition to the suspension stiffness of the suspension - it comprises three phases of distinct stiffness formed by:

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  o two linear stiffness segments, one of which corresponds to the desired stiffness during the compression phase of the suspension, and the other of which corresponds to the desired stiffness during the relaxation phase and is about three times stiffer than the s premiere o a phase of progressive stiffness connection so as to toggle in an extremely regular con of a segment of linear stiffness

to the other.

  The attached drawings are given by way of examples and are not limitative of the invention. They represent only one embodiment of the invention and

  will allow to understand it easily.

  Figures 1 to 3 show schematically the formation of an organ according to the invention.

  FIG. 4 illustrates a first method of mounting the member according to the invention

  s in a suspension, outside the hydraulic part of a shock absorber.

  Figures 5 and 6 show two other examples of mounting the member

  according to the invention in opposition to one of the arms of the suspension.

  Figures 7 and 8 show another embodiment of the mounting of

  suspension in which the member is positioned in a hydraulic shock absorber.

  o Figure 8 illustrates a particular assembly of the stop with means

amortization of its displacement.

  Figure 9 shows schematically the stroke / force curves observed according to the

  chosen suspension mode, namely linear, progressive or contracted @.

  Figure 10 shows an example of theoretical stiffness (Load in daN /

  s Stroke in mm) of a contract suspension.

  Figure 11 shows an example of an effort / displacement curve that can

  reproduce an elastomeric organ according to the invention.

  Figure 9 particularly illustrates the general technical trots

  currently being considered for suspensions for motor vehicles.

  o The curve identified L represents the race / effort relationship produced in the

  suspension frame with linear flexibility.

  The curve identified P presents the case of a suspension with progressive flexibility.

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  Finally, the curve identified C is part of the contract technique. We can see there the existence of two very distinct phases in relaxation and

  in compression with well determined and different stiffnesses.

  In the transition zone between the expansion and compression phases of curve C, a connection flexibility is created. On the ordinate axis, the initial prestress effort fp, as well as the effort interval, are represented.

  correspond to the connection phase fr.

  As a preferential measure, the connection phase corresponding to the reference r is positioned in the first part of the detent stroke, and more precisely between

  ola static position and the first part of the relaxation race.

  The realization of a suspension putting into practice the evolution of the stiffnesses represented in curve C of FIG. 9, requires the use of stops and elements

elastically deformable.

  The present invention presents an organ capable of participating in such a

suspension realization.

  To achieve this, the member presented here by way of example comprises a stop element identified 1 in FIG. 1, as well as a spring element identified 2 in FIG. 2, the stop elements 1 and spring 2 being produced in a single piece 13 visible in

figure 3.

  The shape of the illustrated part 13 is only indicative. The man of the trade is

  able to envisage all realizations producing the characteristics sought.

  In this way, con, it is possible in particular to constitute the spring element necessary for the relaxation phase, as well as the stop capable of producing the connection arc of the

contract suspension.

  The stop element 1 is elastically deformable in compression up to a predetermined force value after which the stop element 1 is no longer deformable. The stiffness of this part of the suspension organ is therefore of the asymptotic type. The other element, the spring element 2, is elastically deformable during

  the compression stress of the suspension member.

  This elastic deformation goes beyond the phase in which the stop of

  connection is put in elastic work.

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  The part 13 thus formed by superposition of these two parts will advantageously be made of an elastomeric material which can easily be produced in

large eerie.

  This forms a single piece 13 of low cost and capable of fulfilling the damping functions related to the relaxation and connection phases of the

contract suspension @.

  As a preference, the suspension member has a substantially elongated shape as shown in FIG. 3, and is hollow in order to allow easy mounting, in particular on a rod as shown in the examples described above.

o below.

  According to a first mounting example illustrated in FIG. 4, the part 13 is mounted in a suspension for a vehicle comprising a shock absorber 6 of common design. As illustrated, the part 13 is mounted outside the hydraulic part of the shock absorber 6 represented, but on the rod 7 of this shock absorber. It is easy to understand the work in expansion and compression of the part 13 thus positioned. In the example shown in FIG. 6, the part 13 is positioned in opposition to an arm 8 for suspension, said arm being pivotable about the axis 9. Again, the part 13 is deformed in compression during the phases of relaxation of the suspension with a preliminary deformation of the stop element 1, and a phase

  successive or only the spring element 2 is deformed.

  In similar fashion, FIG. 5 illustrates another example of mounting of

  the suspension member according to the invention at the level of a suspension arm.

  According to this possibility, the part 13 will advantageously be positioned so that it does not protrude beyond the volume delimited by the suspension arm. Generally speaking, it will be noted that the suspension member of the invention

  can be mounted on all types of suspension existing on the market.

  In another example shown in Figures 7 and 8, the part 13 is mounted

  n / a in the hydraulic part of a shock absorber 6.

  According to Figure 7, the part 13 is adapted to be compressed within the hydraulic part and also mounted on a rod 7 of the damper. In this context, it is advantageous to preserve fluid passages along the part 13 for proper operation of the hydraulic shock absorber 6. In particular, passages

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  in the form of axial grooves 3 in particular visible in FIG. 3 can be formed. The hydraulic operation of the damper 6 is therefore not hampered by the implantation of the part 13, but can be modified by exploiting the rolling of the fluid on the periphery of the elastomer member. By adapting the diameter of the part 13, it is possible to produce a slight friction on the internal wall of the shock absorber in the relaxation phase, the part 13 swelling slightly in compression. This feature can be used to participate in

  damping by producing friction damping.

  o In the variant presented in FIG. 8, a movable floor 11 has been produced surmounting the part 13 and having a plurality of valves 12 for the passage of fluid in order to form the valve function. The abutment surface at the end of the relaxation is not systematically mechanically linked to part 13, and this is due to the floor

mobile 1 1.

  By means of the floor 11, additional damping means are produced during the deformation of the suspension member. Indeed, the movable floor 11 accompanies the deformation of the suspension member, but in

  achieving additional depreciation.

  In the decompression phase of the organ, the damping or complementary function of the floor 11 persists until the complete relaxation of the organ of

  suspension, hence a beneficial effect on comfort.

  It will be noted that the deformation in compression of the suspension member, particularly in elastomer will produce the increase in its diameter. We will therefore adapt the size of the body accordingly to the geometry of the suspension in which it must be integrated, and this not to interfere with the operation

  including hydraulic shock absorber.

  In the preferential application to contractual suspensions @, there is shown in FIGS. 10 and 11 an example of the result capable of being obtained by

[The invention here presented.

  o In this context, Figure 10 shows the evolution of the stiffness of a suspension with, successively, a first linear segment corresponding to the relaxation of the suspension, an intermediate zone of non-linear stiffness located in the relaxation phase and producing a progressive evolution of stiffness, a second segment

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  linear correspond to the compression phase of the suspension. Room 13 of

  [The invention p rod u it, it alone, the first two phases.

  To get effect, a piece 13 with the stiffness properties illustrated by the curve of

  Figure 11 would be able to give satisfaction.

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REFERENCES

  1. Stop element 2. Spring element 3. Axial grooves 4. Shock absorber 5. Rod 6. Suspension arm 7. Pivot axis to 8. Stop surface 9. Movable floor 1 0. Valves 11. Piece elastomers P. Progressive Flexibility Is L. Flexibilitelineaire C. SystemeContractiveO r. Flexible connection fp. Initial prestressing fr. Connection phase lo 2840256

Claims (10)

  1. Suspension member for a vehicle capable of being stressed in compression, comprising a spring element (2) elastically deformable during the compression stress and a stop element (1) elastically deformable only during a first phase of compression stress Characterized by the fact that the stop element (1) and the spring element (2) are formed in the same o piece (13).   2. Body according to claim 1, characterized in that,   The piece (13) is made of elastomer material.   3. Body according to any one of claims 1 to 2, Characterized by the fact,   It is hollow for mounting around a rod (7).   4. Body according to any one of claims 1 to 3,   Characterized by the fact, that it has at least one passage along the organ, on its surface   o exterior, so that it can be mounted in a hydraulic shock absorber.   5. Body according to claim 4, characterized in that,   The wind passage or passages consist of axial grooves (3).   6. Suspension for vehicle, s Characterized by the fact,   That it is equipped with an organ according to any one of claims 1   at 5. 7. Suspension according to claim 6, characterized in that, where the organ is mounted in a manner, con to be stressed in compression during the phases of relaxation of the suspension.   8. Suspension according to claim 7, Characterized by the fact, 11 2840256   That it includes a hydraulic shock absorber (6) in which the member is mounted. 9. Suspension according to claim 8, characterized by the fact, that it comprises a movable floor (11) applying to one end of the organ and provided with at least one valve (12) for passage of fluid, to generate additional cushioning during deformation of the organ.   10. Suspension according to any one of claims 6 to 9,   o Characterized by the fact that - the organ is placed in opposition to the suspension stiffness of the suspension - it comprises three distinct phases of stiffness formed by: o two segments of linear stiffness, one of which corresponds to the desired stiffness during the compression phase of the suspension, and the other of which corresponds to the desired stiffness during the relaxation phase and is approximately three times stiffer than the first, where a connection phase has progressive stiffness so as to topple o fa, extremely regular con of a linear stiffness segment