FR3049226B1 - HYDRAULIC SUSPENSION SYSTEM OF A VEHICLE - Google Patents

Abstract

The invention relates to a hydraulic suspension system for a vehicle, in particular an automobile. The hydraulic suspension system according to the invention comprises a hydraulic expansion stop (15b) whose piston is intended to be displaced in the corresponding cylinder by the piston of the detuned damper (1b) at the same time as the mechanical detent stop (16b) is compressed by the piston of the detented damper when the latter reaches an expansion stroke (CD) in the cylinder of the decarburized damper (1b). The invention finds its application in the field of the automotive industry.

Description

The invention relates to a hydraulic suspension system for a vehicle, in particular a motor vehicle.

In a manner known per se, a hydraulic suspension system of a vehicle, in particular an automobile, comprises for each of the wheels of the vehicle a piston damper movable in its corresponding cylinder and interposed between the body and the wheel stub axle. of the vehicle. The role of this damper is to greatly limit the oscillations transmitted by the wheels to the vehicle when the wheels encounter roughness or obstacles present on the road on which the vehicle is traveling.

[003] In order to limit and dampen the stroke of the piston of the damper, the latter comprises resilient and compressible mechanical attack or expansion stops, or possibly hydraulic. The role of these stops is also to protect the chassis of the vehicle when there are strong deflections of the corresponding wheel, due to incidents or significant obstacles, such as the retarders of the type dos-d'âne or the potholes.

[004] It is known in particular from FR 2995048 a hydraulic piston stop piston movable in its corresponding cylinder, and whose piston is intended to be moved by the piston of the damper when the latter approaches its end of course .

[005] However, as the major strokes of the piston of the damper are mainly of an incidental nature, the comfort of the suspension is not a priority with regard to the preservation of the mechanical integrity of the vehicle. For this reason, the stops of attack and relaxation are generally very stiff and generate discontinuities of brutal efforts. Comfort for the occupants of the vehicle is then strongly penalized in these situations.

The present invention aims to overcome the above disadvantages of the prior art.

[007] To achieve this object, the invention relates to a hydraulic suspension system of a vehicle, including an automobile, comprising for each wheel of the vehicle a detent damper cylinder and movable piston in the cylinder to delimit two chambers resp. and compression, and interposed between the body and the vehicle wheel-knuckle, a hydraulic thrust bearing mounted in the compression chamber and having a cylinder and a piston movable relative to each other, characterized in that it comprises for each wheel a compressible mechanical expansion stop and a piston hydraulic expansion stopper mounted in the expansion chamber, in that it comprises for each wheel a compressible mechanical attack stop positioned between the cylinder and the vehicle body or between the wheel knuckle and the vehicle body, in that the piston and the cylinder of the hydra thrust bearing are intended to be displaced relative to each other by means of the piston of the expander damper when the latter reaches a first attacking stroke in the cylinder of the expander, in that the abutment mechanical attack is intended to be compressed between the cylinder of the decarburized damper and the vehicle body when the piston of the expander damper reaches a second attacking stroke in the cylinder of the supersized damper greater than the first stroke, and in that the piston of the hydraulic expansion stop is intended to be displaced in the corresponding cylinder by the piston of the expander damper at the same time as the mechanical detent stop is compressed by the piston of the expander damper when the latter reaches a third detent stroke in the cylinder of the detachment damper.

[008] According to another feature, the first race in the piston of the piston detaré is between zero and twenty millimeters from a reference attitude of the vehicle.

[009] According to another feature, the second race in the piston of the detared damper is between forty and fifty millimeters from the reference attitude of the vehicle.

[010] According to another feature, the third expansion stroke of the piston of the detachment damper is about twenty millimeters from the reference attitude of the vehicle.

[011] According to another feature, the hydraulic expansion stop is a floating piston surrounding the stem of the expander and positioned in the expansion chamber of the cylinder of the damper removed between the upper end wall of the cylinder of the a detuned damper traversed by the stem of the detuned damper and a flange secured to the stem of the detuned damper.

[012] According to another feature, the mechanical expansion stop is a return spring positioned in the expansion chamber and whose ends are respectively bearing against the floating piston and the upper end wall of the cylinder of the expander damper .

[013] According to another feature, the cylinder of the hydraulic attack stop comprises a plurality of radial holes through the wall of the cylinder and allowing the entry or exit of the liquid from the compression chamber of the cylinder of the expander damper when the piston and the cylinder of the hydraulic thrust stop move relative to one another.

[014] According to another feature, the mechanical attack stop is secured to one end of the damper cylinder, is elastomeric material and has an annular cross section so as to be traversed by the piston rod of the detached damper connected to the vehicle body.

[015] According to another feature, the hydraulic suspension system comprises for each wheel of the vehicle a suspension spring mounted around the expander damper.

[016] The invention also relates to a vehicle, in particular an automobile, comprising a hydraulic suspension system as described above.

[017] The invention will be better understood, and other objects, features, details and advantages thereof will appear more clearly in the explanatory description which follows with reference to the accompanying drawings given solely by way of example illustrating a prior art and an embodiment of the invention and in which: - Figures 1A and 1B show a longitudinal sectional diagram of a damper of the prior art and a graph illustrating the arrangement of the components of the damping according to the stroke of the piston of the damper in the cylinder of the damper; FIGS. 2A and 2B show a longitudinal sectional diagram of a detonated damper according to the invention when the vehicle is at a reference attitude and a graph of the arrangement of the components of the detuned damper corresponding to the position the piston marked in Figure 2A; - Figures 3A and 3B show a longitudinal sectional diagram of a detachment damper according to the invention when the stroke of the damper piston exceeds a first stroke in the cylinder of the shock absorber and a graph of the arrangement of the elements of the detonated damper corresponding to the position of the piston indicated in FIG. 3A; - Figures 4A and 4B show a longitudinal sectional diagram of a detachment damper according to the invention when the piston stroke of the damper exceeds a second stroke in the cylinder of the shock absorber and a graph of the arrangement of the components of the detonated damper corresponding to the position of the piston indicated in FIG. 4A; FIGS. 5A and 5B show a longitudinal sectional diagram of a detonated damper according to the invention when the stroke of the damper piston exceeds a third expansion stroke in the damper cylinder and a graph of the damper. arrangement of the components of the detonated damper corresponding to the position of the piston marked in Figure 5A.

[018] With reference to Figure 1A, a hydraulic suspension system of a vehicle, including automotive, will now be described.

[019] The suspension of the vehicle comprises, for each wheel of the vehicle, a hydraulic damper 1 comprising a body 2 in the form of a cylinder and a piston 3 movable in the cylinder 2. This damper 1 is interposed between the body 6 of the vehicle and the corresponding wheel knuckle. The piston 3, integral with a first end of a rod 14 whose other end is connected to the body 6 of the vehicle, defines in the cylinder 2 two chambers 4, 5 respectively of compression and expansion in which hydraulic fluid incompressible (oil) included in the cylinder 2 is intended to flow on both sides of the piston 3 according to the movements of the latter in the cylinder 2.

[020] The behavior of each hydraulic damper 1 of the vehicle hydraulic suspension system can be described according to a damping law in which the force exerted by the damper 1 depends on the speed of movement of the corresponding wheel. In other words, the faster the piston 3 moves in the cylinder 2 of the damper, the greater the force exerted by the damper 1 on the body 6 of the vehicle is important.

[021] The hydraulic suspension system also comprises, for each wheel of the vehicle, a suspension spring 17 mounted around the damper 1 and whose ends are respectively supported against the body 6 of the vehicle via a cup 18 and against a cup 19 secured to the cylinder 2 of the damper. The suspension spring 17 is a stiffness element whose behavior can be described by a law in which the force exerted by the spring 17 on the body 6 of the vehicle depends on the amplitude of the displacement of the corresponding wheel. In other words, the more the suspension spring 17 is compressed, the greater the force exerted on the body 6 of the vehicle is important. The suspension spring 17 essentially serves to carry the body 6 of the vehicle while allowing the deflections.

[022] The suspension system also comprises for each wheel of the vehicle two respective mechanical 7 and hydraulic 9 attack stops, and two respective mechanical 16 and hydraulic 15 expansion stops.

[023] Each mechanical stop 7, 16 is comparable to a stiffness, and thus exerts a force on the body 6 according to the displacement of the corresponding wheel. In the same way as the suspension spring 17, the force exerted on the body 6 of the vehicle by the mechanical stops respectively of attack 7 and relaxation 16 is even greater than the deflection in attack and relaxation of the corresponding wheel is important.

Each hydraulic striker 9 and trigger 15 is equivalent to a shock absorber and therefore exerts a force on the body 6 of the vehicle according to the speed of travel of the corresponding wheel. In the same way as the hydraulic damper 1, the force exerted on the body 6 of the vehicle by the hydraulic stops respectively of attack 9 and relaxation 15 is even greater than the speed of travel of the corresponding wheel is important.

[025] Referring to Figure 1A, the mechanical attack stopper 7 is secured to one end of the cylinder 2 of the damper and positioned between the cylinder 2 of the damper and the body 6 of the vehicle. It also has an annular cross-section so as to be traversed by the rod 14 of the piston 3 of the damper 1. Thus, when the piston 3 exceeds a certain stroke in attack, the mechanical attack stopper 7 is compressed between end of the cylinder 2 of the damper 1 and the body 6 of the vehicle so as to strongly slow the stroke of the piston 3 in the cylinder 2 of the damper.

[026] Preferably, the mechanical attack stop 7 is elastomer material having a very high stiffness constant, so that the force exerted by the mechanical attack stop 7 on the body 6 of the vehicle increases very rapidly with the deflection in attack of the wheel.

[027] The hydraulic attack stop 9 is mounted in the compression chamber 4 of the cylinder 2 of the damper 1. The hydraulic attack stop 9 comprises a piston 11 secured to the lower bottom wall 12 of the cylinder 2 of the damper, and a cylinder 10 to be moved along the piston 11 of the attack abutment 9 by the piston 3 of the damper 1 when it reaches the vicinity of the end of stroke attack. The cylinder 10 of the hydraulic abutment 7 forms a compression chamber 20 filled with the hydraulic fluid, which is likely to escape from this chamber 20 by leaks around the piston 11 of hydraulic abutment 9 when the piston 3 of the the damper moves the cylinder 10 of the hydraulic attack stop 9 towards the lower bottom wall 12 of the damper. Thus, the piston 3 of the damper 1 arriving near its end stroke attack is very quickly braked.

[028] In addition, the hydraulic attack abutment 9 comprises a return spring 21 surrounding the piston 11 of the hydraulic abutment 9 and whose ends bear against respectively the bottom bottom wall 12 of the cylinder 2 of the damper and the annular end edge bordering the orifice of the cylinder 10 of the hydraulic stop 9. In this way, the return spring 21 allows the cylinder 10 of the hydraulic attack stop 9 to return to the rest position when the piston 3 of the damper 1 moves away from the cylinder 10 of the hydraulic stop 9.

[029] The hydraulic expansion stop 15 is a floating piston surrounding the rod 14 of the damper 1 so as to maintain an annular space 23 between the rod 14 and the inner edge of the floating piston through which the hydraulic fluid is likely to circulate. The hydraulic expansion stop 15 is positioned in the expansion chamber 5 of the cylinder 2 of the damper, between the upper end wall 8 of the cylinder 2 of the damper through which the rod 14 of the damper and a collar 22 forming a valve secured to the rod 14 of the damper. The mechanical expansion stop 16 is in turn a high stiffness spring positioned in the expansion chamber 5 and whose ends bear respectively against the floating piston 15 and the upper end wall 8 of the cylinder 2 of the damper 1.

[030] When the piston 3 of the hydraulic damper 1 moves in the vicinity of its limit end of travel, the flange 22 forming the valve moves the floating piston 15 towards the upper end wall 8 of the cylinder 2 of the 1. The floating piston 15 moving simultaneously compresses the mechanical expansion stop 16. In addition, the flange 22 forming a valve, in contact with the floating piston 15, closes the space 23 between the inner edge of the piston 15 and the rod 14 thus increasing the resistance of the hydraulic expansion stop to the displacement towards the upper end wall 8 of the cylinder 2 of the damper 1. Thus, the piston 3 of the hydraulic damper 1 arriving in the vicinity of its end of race is very quickly braked by the two stops of relaxation 15, 16.

[031] With reference to the graph of Figure 1B, the arrangement of the attacking stops 7, 9 and trigger 15, 16 depending on the stroke of the piston 3 of the damper 1 in the cylinder 2 of the damper 1 will be described.

[032] The vertical scale represents the stroke in millimeters of the piston 3 of the damper in the cylinder 2 of the damper 1 during deflections of the vehicle wheel. The horizontal scale is a visual scale representing the force exerted by each element of the hydraulic suspension at a wheel as a function of the stroke of the piston 3 in the cylinder 2 of the corresponding damper 1. The zero stroke (zero millimeters) corresponds to the position of the piston 3 of the damper 1 in the cylinder when the suspension of the vehicle does not undergo any other effort than that exerted by the mass of the vehicle. The vehicle is then at the reference base AR.

[033] The negative races of the piston 3 of the damper in the cylinder 2 correspond to deflections in attack of the wheel, that is to say that the suspension tends to compress and the body 6 of the vehicle to move closer to the road compared to the reference base AR. Conversely, the positive strokes of the piston 3 of the shock absorber 1 in the cylinder 2 correspond to displacements in relaxation of the wheel, that is to say that the suspension tends to relax and the body 6 of the vehicle to move away from the road relative to the reference base AR.

[034] For simplicity, in the following description, it is considered that the wheel deflections correspond to the strokes of the piston 3 in the corresponding damper. In the case where the damper 1 is inclined relative to a vertical direction, the wheel deflections are greater than the piston strokes 3 of the corresponding damper 1. Of course, the wheel deflections are proportional to the piston stroke 3 of the corresponding damper 1.

[035] It is considered that wheel deflections in attack or relaxation, corresponding to the races in attack or relaxation of the piston 3 of the damper 1, between -15 mm and 15 mm from the reference base AR correspond to low energy DLE deflections which represent the most frequent solicitations encountered on roads of good quality.

[036] It is considered that wheel deflections in attack or relaxation, corresponding to the races in piston attack 3 of the damper 1, between -15 mm and -50 mm from the reference base AR, and displacements of the wheel in attack or in expansion, corresponding to the strokes of the piston 3 of the shock absorber 1, between 15 mm and 50 mm from the reference base AR correspond to medium energy displacements DME which represent solicitations also frequent. These stresses are encountered on slightly degraded roads, where when the wheels cross small obstacles, such as small speed bumps.

[037] Finally, it is considered that wheel deflections in attack or relaxation, corresponding to the races in piston attack 3 of the damper 1, beyond -50 mm from the reference base AR, and deflections of the wheel in attack or relaxation, corresponding to the strokes of the piston 3 of the shock absorber 1, greater than 50 mm from the reference base AR correspond to high energy DHE deflections which represent little solicitations frequent. These stresses are encountered especially when the wheels cross a major hurdle-type retarder in the back of a donkey, or a relatively deep pothole.

[038] For more convenience in the following description, we will discuss the races in attack or relaxation of the piston 3 of the damper 1 in absolute value.

[039] Referring to the graph of Figure 1 B, the mechanical attack stop 7 is compressed as soon as the stroke of the piston 3 of the damper 1 exceeds an attacking stroke of about 10 mm. Thus, the mechanical attack stop 7 intervenes quickly to slow the stroke of the piston 3 of the damper 1 from the medium energy deflections DME. Beyond an attack stroke of the piston 3 of the damper 1 of 50 mm, that is to say for high energy deflections DHE, the piston 3 of the hydraulic damper 1 causes the displacement of the cylinder 10 of the hydraulic attack stop 9 around its corresponding piston 11, to quickly brake the piston 3 of the damper 1 in its corresponding cylinder 2 and better protect the body 6 of the vehicle.

[040] Referring again to the graph of Figure 1 B, the floating piston 15 of the hydraulic expansion stop is moved and simultaneously compresses the spring constituting the mechanical expansion stop 16 when the expansion stroke of the piston 3 of the damper 1 exceeds a value of about 70 mm, to quickly brake the piston 3 of the damper 1 in its corresponding cylinder 2.

[041] These stroke values in attack and relaxation of the piston 3 of the damper 1 are of course revised downward if the damper 1 is inclined relative to a vertical direction.

[042] With reference to Figures 2A, 2B, 3A, 3B, 4A, 4B, 5A and 5B, the suspension system according to the invention will now be described.

[043] It comprises for each wheel of the vehicle a suspension spring 17 as described above.

[044] The suspension system according to the invention comprises for each wheel of the vehicle a detuned hydraulic damper 1b. A detuned hydraulic damper 1b is a hydraulic damper which has been relaxed, that is to say that the orifices ensuring the passage of hydraulic fluid on either side of the piston 3 in one or other of the chambers of compression 4 and relaxation 5 of the detuned hydraulic damper 1b are wider than the orifices of a shock absorber 1 of the prior art. In this way, for a displacement speed of the piston 3 of the shock absorber 1.1b identical, the force exerted by the damping detaré 1b on the vehicle body is less than the force exerted by the damper 1 of the prior art. For example, a detuned damper 1b positioned at the front axle exerts a force on the body 6 of the vehicle 50% less than the force exerted by an unassisted conventional hydraulic damper 1, and a detuned damper 1b positioned at the rear axle exerts a force on the body 6 of the vehicle 20% less than the effort exerted by an unassisted conventional hydraulic damper 1.

[045] To compensate for the decrease in the damping force in attack exerted by the detuned damper 1b on the body 6 of the vehicle, the hydraulic suspension system according to the invention also comprises for each wheel of the vehicle a stop of mechanical attack 7b shorter than the mechanical attack stop 7 of the prior art, as well as, preferably, a hydraulic attack stop 9b whose cylinder 10b has an amplitude of displacement around the corresponding piston 11b between its end of stroke in attack and its end of course in relaxation for example between 40 and 60 mm. This displacement amplitude is greater than the displacement amplitude of the cylinder 10 of the hydraulic attack stop 9 of the prior art, which is of the order of 30 mm.

[046] In addition, the structure of the cylinder 10b of the hydraulic abutment 9b is different, since the cylinder 10b comprises in its wall a plurality of through radial holes 13, and allowing the entry or exit of the hydraulic fluid of the compression chamber 4 of the cylinder 2 of the detuned damper 1b when the piston 11b and the cylinder 10b of the hydraulic abutment 9b move relative to each other. Thus, as the cylinder 10b of the hydraulic thrust bearing 9b moves around the corresponding piston 11b towards the bottom bottom wall 12 of the cylinder 2 of the expander 1b, an increasing number of through holes 13 are blocked by the piston 11b of the hydraulic thrust bearing 9b, thus decreasing the overall cross section of the through holes 13 so that the force exerted by the hydraulic thrust bearing 9b on the body 6 of the vehicle increases for a speed of movement of the cylinder 10b constant.

[047] The arrangement of the mechanical attack abutments 7b and hydraulic 9b as a function of the strokes of the piston 3 of the detuned damper 1b is also different from that of the prior art.

[048] Indeed, when the plunger 3 of the detuned hydraulic damper 1b exceeds an attack stroke CA1 of between 0 and 20 mm, preferably 10 mm, the latter causes the displacement of the cylinder 10b of the hydraulic attack stop 9b around its corresponding piston 11b. For low and medium energy deflections, the overall section of a large number of holes 13 passing through the cylinder 10b of the hydraulic attack stop 9b is sufficiently high to ensure gentle braking of the piston 3 of the expander 1b. For DHE higher energy deflections in which the piston 3 of damped decelerator 1b is approaching its end of attack stroke, the overall section of a smaller number of holes 13 through the cylinder 10b of the abutment 9b hydraulic attack decreases because an increasing number of through holes 13 are plugged by the piston 11b of the hydraulic thrust bearing 9b as the cylinder 10b moves around the piston 11b of the hydraulic thrust bearing 9b towards the lower bottom wall 12 of the cylinder 2 of the damper 1: this ensures a more sudden braking of the piston 3 of the detuned damper 1b in order to protect the body 6 and the chassis of the vehicle.

[049] In addition, as soon as the piston 3 of the detuned damper 1b exceeds an attack stroke CA2 between 30 and 50 mm, preferably between 40 and 50 mm, the mechanical abutment 7b is compressed and participates in the reinforcement braking piston 3 of the expander 1b.

[050] To compensate for the decrease of the damping force in relaxation exerted by the detuned damper 1b on the body 6 of the vehicle, the hydraulic suspension system according to the invention also comprises for each wheel of the vehicle a detent stop mechanical 16b longer than the mechanical expansion stop 16 of the prior art. Therefore, the floating piston of the hydraulic expansion stopper 15b according to the invention has an amplitude of displacement around the rod 14 of the detuned damper 1b, between its rest position and its end-of-travel relaxation position, included for example between 40 and 80 mm. This displacement amplitude is greater than the displacement amplitude of the floating piston of the hydraulic expansion stopper 15 of the prior art, which is of the order of 20 to 30 mm. In addition, the extension of the displacement amplitude of the hydraulic expansion stop 15b makes it possible to reduce the stiffness of the spring of the mechanical expansion stop 16b, so that it contributes little to the braking of the piston 3 of the shock absorber detaré 1b relaxation. In addition, the floating piston 15b of the hydraulic expansion stop is formed by an annular ring that is radially split over its entire thickness and is intended to slide along the rod 14 of the expander 1b so as to maintain an annular space 23b between the rod 14 and the internal edge of the floating piston 15b, while the upper part of the expansion chamber 5 of the cylinder 2 of the detuned damper 1b comprises a wall 2b of substantially frustoconical shape whose cross section decreases in the upper direction towards the wall 8 of the expander 1b. Thus, the force exerted by the detent stops 15b, 16b on the vehicle body increases very gradually with the stroke of the floating piston 15b: as the floating piston 15b moves towards the upper end wall 8 of the cylinder 2 of the detuned damper 1b along the frustoconical wall 2b, the slot and the annular space 23b of the floating piston 15b closes gradually, thereby decreasing the passage section of the hydraulic fluid. This therefore ensures a variable damping according to the stroke of the floating piston 15b, significantly improving control of the vertical movements of the vehicle body, and thus the comfort of the vehicle.

[051] The arrangement of the mechanical expansion stops 16b and hydraulic 15b as a function of the strokes of the piston 3 of the expander 1b is also different compared to that of the prior art.

[052] Indeed, when the piston 3 of the detuned hydraulic damper 1b exceeds a relaxation stroke CD between 10 and 50 mm, preferably 20 mm, the flange 22 moves the floating piston 15b towards the end wall Upper 8 of the cylinder 2 of the expander 1b. The floating piston 15b moving then simultaneously compresses the mechanical expansion stop 16b. Thus, as soon as the piston 3 of the hydraulic damper 1b exceeds the relaxation stroke CD, the latter is gradually braked by the two stops of relaxation 15b, 16b.

[053] The comfort of the suspension is significantly improved by the hydraulic suspension system of the invention. Indeed, the discontinuity of the force exerted by the suspension system, and generator of discomfort for the passengers of the vehicle, is greatly reduced thanks to the hydraulic attack stop 9b, whose cylinder 10b has an extended range of displacement which acts before the mechanical attack stop 7b. In addition, the force exerted by the hydraulic attack stop 9b depending both on the speed and the displacement amplitude of the piston 3 of the detuned damper 1b in its cylinder 2, the braking of the piston 3 of the The shock absorber is adapted to the amplitude and the speed of its stroke in the cylinder 2, which also has a positive effect on passenger comfort. The hydraulic attack stop 9b dissipates the energy without accumulating it, thus avoiding any stimulus effect during low and medium energy deflections. The combined use of a hydraulic expansion stop 15b whose floating piston has a greater amplitude of displacement and a mechanical expansion stop 16b whose spring has a relatively low stiffness allows a progressive increase in the braking of the piston 3 of the detuned damper 1b during the expansion travel of the wheel of the corresponding vehicle, significantly improving the control of the vertical movements of the body 6 of the vehicle. In addition, the additional damping provided by the hydraulic attacking stops 9b and the expansion stops 15b as soon as the medium energy displacements DME compensates for the increased flexibility of the detuned damper 1b. [054] Moreover, when turning, the outer side of the vehicle has elements of the suspension moving in attack and the inner side of the vehicle has elements of suspension in relaxation. The combined use of the attack and detent stops according to the invention increases the level of damping as a function of the amplitude of the roll of the vehicle, which improves the stability of the latter in turns. Finally, the use of a detuned damper 1b reduces the efforts of the suspension during low energy DLE deflections. The body 6 of the vehicle thus freely discusses attack and relaxation, accentuating the feeling of comfort of the occupants of the vehicle. This increased flexibility of the detuned damper 1b is of course compensated by the additional damping provided by the hydraulic attack stop 9b, the hydraulic expansion stop 15b and the mechanical expansion stop 16b from the medium energy DME deflections.

[055] The configuration as described is not limited to the embodiment described above and shown in Figures 2A, 2B, 3A, 3B, 4A, 4B, 5A, 5B. It has been given only as a non-limiting example. Multiple modifications can be made without departing from the scope of the invention. In particular, the invention is not limited to a single hydraulic thrust bearing configuration 9b. One could for example imagine a hydraulic attack stop 9b whose cylinder 10b is secured to the inner walls of the compression chamber 4 of the detuned damper 1b and whose piston 11b is intended to be moved in its corresponding cylinder 10b by the piston 3 of the detuned damper 1b. Of course, any type of hydraulic drive stop 9b known and adapted to be housed in the compression chamber 4 of a damper 1 may be considered. In particular, the use of a hydraulic attack stopper 9b, whose displacement amplitude of the piston 11b or the cylinder 10b is as described in the prior art, is perfectly conceivable as long as the piston 3 of the 1b detuned damper is able to ensure the displacement of the piston 11b or the cylinder 10b of the hydraulic attack stop 9b from the medium energy deflections DME. It could also be imagined for each wheel of the vehicle a suspension spring 17 remote outside the hydraulic damper detaré 1, mounted in parallel with the hydraulic damper débé 1b between the wheel knuckle and the body 6 of the vehicle . Finally, it could be envisaged that at the rear axle of the vehicle, the mechanical attack stops (7b) are offset and each interposed between the stub axle of the corresponding wheel and the body (6) of the vehicle.

Claims (2)

A system for the hydraulic suspension of a vehicle, in particular an automobile, comprising for each wheel of the vehicle a detuned damper (1b) with a cylinder (2) and a piston (3) movable in the cylinder (2) in order to delimit two chambers (4 , 5) respectively of relaxation and compression, and interposed between the body (6) and the vehicle wheel-knuckle, a hydraulic attack stop (9b) mounted in the compression chamber (4) and comprising a cylinder (10b) and a piston (11b) movable relative to each other, characterized in that it comprises for each wheel a compressible mechanical expansion stop (16b) and a piston hydraulic expansion stop (15b) mounted in the expansion chamber (5), in that it comprises for each wheel a compressible mechanical attack abutment (7b) positioned between the cylinder (2) and the body (6) of the vehicle or between the stub axle wheel and the body (6) of the vehicle, in that the piston (11b) and the cyl indre (10b) of the hydraulic thrust bearing (9b) are intended to be displaced relative to each other via the piston (3) of the expander (1b) when the latter reaches a first attack stroke (CA1) in the cylinder (2) of the expander (1b), in that the mechanical attack stop (7b) is intended to be compressed between the cylinder (2) of the expander and the body (6) of the vehicle when the plunger (1b) of the plunger (3) reaches a second stroke (CA2) in the cylinder of the upset damper greater than the first stroke (CA1), and the piston of the hydraulic expansion stop (15b) is intended to be displaced in the corresponding cylinder (2) by the piston (3) of the expander (1b) at the same time as the mechanical expansion stop (16b). ) is compressed by the piston (3) of the expander (1b) when the latter reaches a tr eighth rebound stroke (CD) in the cylinder (2) of the decarburised damper (1b). 2. suspension system according to claim 1, characterized in that the first stroke (CA1) of the piston (3) of the detared damper (1b) is between zero and twenty millimeters from a reference base (AR) of the vehicle. 3. Suspension system according to claim 1 or 2, characterized in that the second stroke (CA2) of the piston (3) of the detared damper (1b) is between forty and fifty millimeters from the plate reference (AR) of the vehicle. 4. Suspension system according to any one of claims 1 to 3, characterized in that the third expansion stroke (CD) of the piston (3) of the detared damper (1b) is between ten and twenty millimeters from the reference attitude (AR) of the vehicle. 5. Suspension system according to any one of claims 1 to 4, characterized in that the hydraulic expansion stop is a floating piston (15b) surrounding the rod (14) of the expander (1b) and positioned in the expansion chamber (5) of the cylinder (2) of the damper removed between the upper end wall (8) of the cylinder (2) of the detented damper traversed by the stem (14) of the detared damper and a flange (22) integral with the rod (14) of the expander (1b). 6. Suspension system according to claim 5, characterized in that the mechanical expansion stop (16b) is a return spring positioned in the expansion chamber (5) and whose ends bear respectively against the floating piston (15b). ) and the upper end wall (8) of the cylinder (2) of the expander (1b). 7. Suspension system according to any one of claims 1 to 6, characterized in that the cylinder (10b) of the hydraulic abutment (9b) comprises a plurality of radial holes (13) passing through the wall of the cylinder ( 10b) and allowing entry or exit of the liquid from the compression chamber of the cylinder (10b) of the detuned damper (1b) when the piston (11b) and the cylinder (10b) of the hydraulic stop ( 9b) move relative to each other. 8. Suspension system according to any one of claims 1 to 7, characterized in that the mechanical attack stop (7b) is integral with one end (8) of the cylinder (2) of the damper (1). and is made of elastomeric material, and in that it has an annular cross-section so as to be traversed by the rod (14) of the piston of the detared damper (1b) connected to the body (6) of the vehicle. 9. A suspension system according to any one of claims 1 to 8, characterized in that it comprises for each wheel of the vehicle a suspension spring (17) mounted around the dyed damper (1b). 10. Vehicle, especially automobile, comprising a hydraulic suspension system according to any one of claims 1 to 9.