WO2020169893A1 - Hydraulic shock absorber provided with a self-adjustable limit stop - Google Patents

Hydraulic shock absorber provided with a self-adjustable limit stop Download PDF

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Publication number
WO2020169893A1
WO2020169893A1 PCT/FR2019/053255 FR2019053255W WO2020169893A1 WO 2020169893 A1 WO2020169893 A1 WO 2020169893A1 FR 2019053255 W FR2019053255 W FR 2019053255W WO 2020169893 A1 WO2020169893 A1 WO 2020169893A1
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WO
WIPO (PCT)
Prior art keywords
shock absorber
tube
bores
piston
stop
Prior art date
Application number
PCT/FR2019/053255
Other languages
French (fr)
Inventor
Frederic RIGUEL
Christophe Monteil
Alan CAVAREC
Jean Marc ALLEGRE
Francis Bontron
Original Assignee
Psa Automobiles Sa
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Application filed by Psa Automobiles Sa filed Critical Psa Automobiles Sa
Publication of WO2020169893A1 publication Critical patent/WO2020169893A1/en

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16FSPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32Details
    • F16F9/48Arrangements for providing different damping effects at different parts of the stroke
    • F16F9/49Stops limiting fluid passage, e.g. hydraulic stops or elastomeric elements inside the cylinder which contribute to changes in fluid damping
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16FSPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32Details
    • F16F9/50Special means providing automatic damping adjustment, i.e. self-adjustment of damping by particular sliding movements of a valve element, other than flexions or displacement of valve discs; Special means providing self-adjustment of spring characteristics
    • F16F9/512Means responsive to load action, i.e. static load on the damper or dynamic fluid pressure changes in the damper, e.g. due to changes in velocity
    • F16F9/5123Means responsive to load action, i.e. static load on the damper or dynamic fluid pressure changes in the damper, e.g. due to changes in velocity responsive to the static or steady-state load on the damper
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16FSPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/10Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using liquid only; using a fluid of which the nature is immaterial
    • F16F9/14Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect
    • F16F9/16Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts
    • F16F9/18Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts with a closed cylinder and a piston separating two or more working spaces therein
    • F16F9/185Bitubular units

Definitions

  • the present invention relates to a hydraulic shock absorber having an end stop, as well as to a motor vehicle equipped with this type of shock absorber.
  • Motor vehicles generally include for each wheel a suspension comprising a suspension spring, and a hydraulic telescopic shock absorber which slows down the movements of this suspension.
  • the shock absorber can include a hydraulic end stop, which stops the movement at the end of the stroke to avoid an impact on a rigid stop.
  • a known type of hydraulic adjustable limit stop presented in particular by document US Pat. No. 32077270, comprises a rod receiving an axial thrust from a movement to be braked, driving a piston sliding in a cylinder having a series of distributed bores. lengthwise.
  • a manual control system located outside the cylinder adjusts the closure of these holes in order to adjust the level of braking of the stop.
  • a stop known for a vehicle suspension shock absorber comprises a jack rod comprising at its lower end a damping piston to achieve the main damping, extending towards the bottom by a shirt which at the end of the compression stroke is adjusted around an inner stop tube.
  • the sleeve has a series of axially distributed bores, which are closed one after the other when the tube is introduced into this sleeve in order to brake more and more strongly the transfer of fluid coming from from the outer chamber formed around the liner, to the chamber in front of the piston inside the tube. Increasingly higher braking is obtained at the compression limit switch of the shock absorber.
  • a thrust spring disposed below the main piston comes a little before the end of the shock absorber stroke to press on a valve sliding axially in the stop tube which has additional holes at different heights.
  • a control chamber arranged in the stop tube below the plug has a limited passage of fluid to the outside in order to slow down the downward movement of this plug under the effect of the thrust spring, and the upward movement of this bushel under the effect of a return spring.
  • this type of stopper comprising an adjustable valve inside the stopper tube is not suitable for a hydraulic end-of-travel stopper comprising a piston coming inside the stopper tube having bores distributed over its length.
  • the object of the present invention is in particular to avoid these drawbacks of the prior art.
  • a hydraulic shock absorber comprising a shock absorber piston moving axially during compression in a direction called forward which is turned towards a shock absorber base, receiving forward a rod comprising at its end a piston re-entering stop in a fixed end-of-travel stop tube having bores which slow down the fluid leaving this tube, this damper being remarkable in that it comprises a valve sliding around the tube, held axially between a front return spring bearing on the shock absorber base to return it to a rear position, and a rear return spring resting on the shock absorber piston to return it to a front position, the valve comprising a rear seat closing in the rear position of the rear holes of the tube and a front bearing surface closing in the front position of the front bores of the tube, and comprising a chamber separated axially into two volumes by a fixed sealing segment.
  • the plug In the case of a lightly loaded vehicle, the plug is returned to the rear position, which closes the rear holes in the tube and frees the front holes by giving a braking law over a large travel of the stop for lightly loaded vehicle ensuring the comfort.
  • the rapid operations of the stopper do not move the bushel because of its slow dynamics.
  • the hydraulic shock absorber according to the invention may further include one or more of the following features, which may be combined with one another.
  • the chamber forms an annular volume in contact with the tube, closed at the ends by the bearing surfaces of the plug resting on this tube.
  • the sealing segment has an internal diameter fixed in an external groove of the tube, and an external diameter fitted in the chamber.
  • the sealing segment advantageously has a fluid leakage rate between the two volumes.
  • the front and rear positions of the plug are each defined by a ring fitted in an outer groove of the tube.
  • the return springs are helical springs fitted in an inner tube receiving the damper piston.
  • the bores in the tube form longitudinal slots starting from the rear end of this tube, having a width which narrows towards the front, the rear bores being arranged axially at these slots.
  • the rear bores have a total section of the passage of the fluid greater than that of the front passages.
  • the front bores are arranged behind the end of stroke of the stop piston.
  • the subject of the invention is also a motor vehicle equipped with hydraulic suspension dampers, comprising dampers comprising any of the preceding characteristics.
  • FIG. 1 shows in axial section the front part of a shock absorber according to the invention at rest, the vehicle being unladen;
  • FIG. 2 shows this shock absorber in operation at the start of the end stop
  • FIG. 3 shows this shock absorber in operation at the end of the end stop
  • FIG. 4 shows the shock absorber at rest with the vehicle loaded
  • Figure 1 shows a telescopic shock absorber comprising on the front side indicated by the arrow AV, an inner tube 4 disposed in an outer tube 2 forming a body, containing a shock absorber piston 6 fixed on a rod 8 separating two hydraulic chambers to achieve the main damping of the suspension movement.
  • the volume between the outer 2 and inner 4 tubes containing a pressurized gas receives the overflow of fluid coming from the inlet of the rod 8 into the damper during its compression.
  • the rod 8 comprises an extension 10 in front of the shock absorber piston 6, comprising at its front end a stop piston 12 equipped on its periphery with a seal, which returns towards the end of stroke of the shock absorber in a stop tube 14 comprising a front end base 16 linked to the outer 2 and inner 4 tubes.
  • Stopper tube 14 has longitudinal slots 20 extending from its rear end, covering nearly half of its length, having a large width at the rear end, which gradually narrows forward.
  • the stop tube 14 further comprises two series of bores, each aligned transversely, comprising rear bores 22 disposed approximately at the first third of the front end of the slots 20, and front bores 24 arranged near the front base 16.
  • a plug 30 slides between the stop tube 14 and the inner tube 4, allowing free passage of the fluid on each side by virtue of outer longitudinal slots 32 formed around this plug.
  • the plug 30 comprises a front annular seat 36 and a rear annular seat 38 fitted around the stop tube 14, forming a guide comprising a seal on this tube.
  • the plug 30 can slide along a limited stroke on each side by an annular ring 34 engaged in an outer groove of the stop tube 14, between a rear position where its rear seat 38 closes the rear holes 22, and a front position where its seat front 36 closes the front holes 24.
  • the segment 42 has an outer contour fitted to the surface of the annular chamber, so as to axially separate a front volume and a rear volume of this chamber, allowing a small leakage rate between them.
  • a slow sliding dynamic of the plug 30 is obtained, given by the transfer of fluid between the two volumes of the annular chamber 40, which is slowed down by the leakage rate around the segment 42.
  • the valve 30 is held axially between two helical return springs fitted in the inner tube 4, comprising a front return spring 44 bearing on the end base 16 to return the valve to a rear position resting on the rear ring 34 , where the rear holes 22 are closed, the front holes 24 remaining open.
  • a rear return spring 46 is supported on the damper piston 6 to return the valve 30 to a front position resting on the front ring 34, with the front holes 24 closed and the rear holes 22 open.
  • the return springs 44, 46 are guided in the inner tube 4 which ensures low friction and absence of noise.
  • annular chamber 40 can be formed outside the plug 30 against the inner tube 4, with a segment attached to this tube.
  • the shock absorber passes quickly over the end stop, with a frequency of about one Hertz which is that of the suspension, do not modify this position of the valve thanks to the slow dynamics of transfer in its annular chamber 40.
  • FIG. 2 shows the shock absorber at the start of its end of travel, the stop piston 12 having entered the stop tube 14. There is weak braking at the start thanks to the flow of fluid passing through a wide part of the slots 20, and by the front holes 24.
  • FIG. 3 shows the shock absorber at the end of its end of stroke, the stop piston 12 having reached the end of the stop tube 14, with progressive braking throughout this important stroke including first of all the closing of the slots 20. We then have the operation with only the holes front 24, which are closed a little before the end of the limit switch in order to apply vigorous braking at this end.
  • a high level of comfort is obtained with progressive braking over the entire travel of the end stop.
  • FIG. 4 shows the loaded vehicle at rest, the stop piston 12 arriving just at the start of the stop tube 14.
  • the pressure of the rear return spring 46 pushes the plug 30 forward by compressing the front return spring 44, which moves this bushel by freeing the rear holes 22 and closing the front holes 24.
  • the rear bores 22 have a total passage section greater than that of the front bores 24. Damping is effected mainly by the operation of the damper piston 6.
  • FIG. 5 shows the vehicle with the shock absorber arriving at the start of the end of travel, the stop piston 12 having just closed the rear holes 22.
  • the shock absorber piston 6 rises by reducing the pressure on the rear return spring 46.
  • the valve 30 also rises under the effect of the front return spring 44, with a slow dynamic to return to the position. original shown in figure 1.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Fluid-Damping Devices (AREA)
  • Axle Suspensions And Sidecars For Cycles (AREA)

Abstract

The invention relates to a hydraulic shock absorber comprising a shock absorber piston (6) receiving, towards the front, a rod (10) comprising a stop piston (12) entering a fixed limit stop tube (14) having bores (20, 22, 24) which slow the fluid leaving this tube (14), this shock absorber comprising a bushing (30) sliding around the tube (14), held axially between a front spring (44) returning it into a rear position, and a rear spring (46) bearing on the shock absorber piston (6) to return it to a front position, the bushing (30) comprising a rear bearing surface (38) which, in the rear position, closes rear bores of the tube (22) and a front bearing surface (36) which, in the front position, closes front bores of the tube (24), and comprising a chamber (40) separated axially into two volumes by a fixed sealing segment (42).

Description

DESCRIPTION DESCRIPTION
Titre : AMORTISSEUR HYDRAULIQUE EQUIPE D’UNE BUTEE Title: HYDRAULIC SHOCK ABSORBER EQUIPPED WITH A STOPPER
DE FIN DE COURSE AUTO-ADAPTABLE SELF-ADAPTABLE LIMIT SWITCH
La présente invention concerne un amortisseur hydraulique disposant d’une butée de fin de course, ainsi qu’un véhicule automobile équipé de ce type d’amortisseur. The present invention relates to a hydraulic shock absorber having an end stop, as well as to a motor vehicle equipped with this type of shock absorber.
Les véhicules automobiles comportent généralement pour chaque roue une suspension comprenant un ressort de suspension, et un amortisseur télescopique hydraulique qui freine les mouvements de cette suspension. En particulier l’amortisseur peut comporter une butée hydraulique de fin de course, qui arrête le mouvement en bout de course pour éviter un choc sur une butée rigide. Motor vehicles generally include for each wheel a suspension comprising a suspension spring, and a hydraulic telescopic shock absorber which slows down the movements of this suspension. In particular, the shock absorber can include a hydraulic end stop, which stops the movement at the end of the stroke to avoid an impact on a rigid stop.
Un type de butée hydraulique de fin de course réglable connu, présenté notamment par le document US-A-32077270, comporte une tige recevant une poussée axiale d’un mouvement à freiner, entraînant un piston coulissant dans un cylindre présentant une série de perçages répartis sur la longueur. Un système de commande manuelle disposé à l’extérieur du cylindre, permet de régler la fermeture de ces perçages afin d’ajuster le niveau de freinage de la butée. A known type of hydraulic adjustable limit stop, presented in particular by document US Pat. No. 32077270, comprises a rod receiving an axial thrust from a movement to be braked, driving a piston sliding in a cylinder having a series of distributed bores. lengthwise. A manual control system located outside the cylinder adjusts the closure of these holes in order to adjust the level of braking of the stop.
Toutefois le réglage de ce type de butée ne comporte aucun automatisme permettant de s’adapter à différentes charges. However, the adjustment of this type of stop does not include any automatic mechanism to adapt to different loads.
Un autre type de butée connu pour un amortisseur de suspension de véhicule, présenté notamment par le document FR-A1 -3050000, comporte une tige de vérin comprenant à son extrémité inférieure un piston d’amortissement pour réaliser l’amortissement principal, se prolongeant vers le bas par une chemise qui en fin de course de compression vient s’ajuster autour d’un tube intérieur de butée. Another type of stop known for a vehicle suspension shock absorber, presented in particular by document FR-A1 -3050000, comprises a jack rod comprising at its lower end a damping piston to achieve the main damping, extending towards the bottom by a shirt which at the end of the compression stroke is adjusted around an inner stop tube.
La chemise comporte une série de perçages répartis axialement, qui sont fermés les uns après les autres lors de l’introduction du tube dans cette chemise afin de freiner de plus en plus fortement le transfert de fluide venant de la chambre extérieure formée autour de la chemise, vers la chambre en avant du piston à l’intérieur du tube. On obtient un freinage de plus en plus élevé de la fin de course de compression de l’amortisseur. The sleeve has a series of axially distributed bores, which are closed one after the other when the tube is introduced into this sleeve in order to brake more and more strongly the transfer of fluid coming from from the outer chamber formed around the liner, to the chamber in front of the piston inside the tube. Increasingly higher braking is obtained at the compression limit switch of the shock absorber.
Un ressort de poussée disposé en dessous du piston principal, vient un peu avant la fin de course de l’amortisseur presser sur un boisseau coulissant axialement dans le tube de butée qui comporte des perçages additionnels à différentes hauteurs. A thrust spring disposed below the main piston, comes a little before the end of the shock absorber stroke to press on a valve sliding axially in the stop tube which has additional holes at different heights.
Une chambre de contrôle disposée dans le tube de butée en dessous du boisseau, comporte un passage limité de fluide vers l’extérieur afin de freiner le mouvement de descente de ce boisseau sous l’effet du ressort de poussée, et le mouvement de remontée de ce boisseau sous l’effet d’un ressort de rappel. A control chamber arranged in the stop tube below the plug, has a limited passage of fluid to the outside in order to slow down the downward movement of this plug under the effect of the thrust spring, and the upward movement of this bushel under the effect of a return spring.
De cette manière un appui rapide du ressort de poussée sur le boisseau, lors d’un débattement important de la suspension réalisé de manière occasionnelle pour un véhicule peu chargé, ne descend pas le boisseau freiné par le fluide de la chambre de contrôle, présentant une dynamique lente. Les perçages du tube de butée restent ouverts, donnant une grande souplesse à la butée de fin de course ce qui apporte un confort élevé. In this way, rapid support of the thrust spring on the valve, during a large travel of the suspension carried out occasionally for a lightly loaded vehicle, does not lower the valve braked by the fluid from the control chamber, presenting a slow dynamics. The holes in the stop tube remain open, giving the limit stop great flexibility, which provides high comfort.
Un appui fréquent du ressort de poussée sur le boisseau, avec un véhicule chargé entraînant cette fréquence, finit par descendre le boisseau qui ferme des perçages du tube de butée en durcissant plus fortement la butée de fin de course. On obtient une sécurité en évitant un talonnement de la suspension pour ce véhicule chargé. Frequent pressing of the thrust spring on the plug, with a loaded vehicle driving this frequency, ends up lowering the plug which closes the bores of the stop tube by hardening the end stop more strongly. Safety is obtained by avoiding bottoming out of the suspension for this loaded vehicle.
Toutefois ce type de butée comprenant un boisseau réglable intérieur au tube de butée, ne convient pas pour une butée hydraulique de fin de course comportant un piston venant à l’intérieur du tube de butée présentant des perçages répartis sur sa longueur. However, this type of stopper comprising an adjustable valve inside the stopper tube is not suitable for a hydraulic end-of-travel stopper comprising a piston coming inside the stopper tube having bores distributed over its length.
La présente invention a notamment pour but d’éviter ces inconvénients de la technique antérieure. The object of the present invention is in particular to avoid these drawbacks of the prior art.
Elle propose à cet effet un amortisseur hydraulique comportant un piston d’amortisseur se déplaçant axialement lors d’une compression dans une direction appelée avant qui est tournée vers un fond d’amortisseur, recevant vers l’avant une tige comprenant à son extrémité un piston de butée rentrant dans un tube fixe de butée de fin de course présentant des perçages qui freinent le fluide sortant de ce tube, cet amortisseur étant remarquable en ce qu’il comporte un boisseau coulissant autour du tube, maintenu axialement entre un ressort de rappel avant prenant appui sur le fond d’amortisseur pour le rappeler dans une position arrière, et un ressort de rappel arrière prenant appui sur le piston d’amortisseur pour le rappeler dans une position avant, le boisseau comprenant une portée arrière fermant dans la position arrière des perçages arrière du tube et une portée avant fermant dans la position avant des perçages avant du tube, et comprenant une chambre séparée axialement en deux volumes par un segment d’étanchéité fixe. It provides for this purpose a hydraulic shock absorber comprising a shock absorber piston moving axially during compression in a direction called forward which is turned towards a shock absorber base, receiving forward a rod comprising at its end a piston re-entering stop in a fixed end-of-travel stop tube having bores which slow down the fluid leaving this tube, this damper being remarkable in that it comprises a valve sliding around the tube, held axially between a front return spring bearing on the shock absorber base to return it to a rear position, and a rear return spring resting on the shock absorber piston to return it to a front position, the valve comprising a rear seat closing in the rear position of the rear holes of the tube and a front bearing surface closing in the front position of the front bores of the tube, and comprising a chamber separated axially into two volumes by a fixed sealing segment.
Un avantage de cet amortisseur est que le boisseau coulissant autour du tube, comportant les deux volumes de la chambre séparés par le segment d’étanchéité, présente avec un débit de fuite une dynamique de déplacement lente sous l’effet des deux ressorts de rappel. An advantage of this damper is that the valve sliding around the tube, comprising the two chamber volumes separated by the sealing segment, has a slow displacement dynamic with a leakage rate under the effect of the two return springs.
Dans le cas d’un véhicule peu chargé le boisseau est rappelé dans la position arrière, ce qui ferme les perçages arrière du tube et libère les perçages avant en donnant une loi de freinage sur une grande course de la butée pour véhicule peu chargé assurant le confort. Les fonctionnements rapides de la butée ne déplacent pas le boisseau à cause de sa dynamique lente. In the case of a lightly loaded vehicle, the plug is returned to the rear position, which closes the rear holes in the tube and frees the front holes by giving a braking law over a large travel of the stop for lightly loaded vehicle ensuring the comfort. The rapid operations of the stopper do not move the bushel because of its slow dynamics.
Dans le cas d’un véhicule fortement chargé la pression du ressort de rappel arrière s’appliquant pendant longtemps finit par déplacer le boisseau, ce qui libère les perçages arrière et ferme les perçages avant du tube. On obtient alors un fonctionnement neutralisé de la butée pour le début de sa course laissant le fonctionnement uniquement du piston d’amortisseur, et un freinage plus important pour sa fin de course adapté à la charge, ce qui permet de conserver un confort de conduite. In the case of a heavily loaded vehicle, the long-applied rear return spring pressure eventually displaces the plug, freeing the rear bores and closing the front bores of the tube. This results in neutralized operation of the stop for the start of its stroke, leaving the operation only of the shock absorber piston, and greater braking for its limit switch adapted to the load, which allows driving comfort to be maintained.
L’amortisseur hydraulique selon l’invention peut comporter de plus une ou plusieurs des caractéristiques suivantes, qui peuvent être combinées entre elles. The hydraulic shock absorber according to the invention may further include one or more of the following features, which may be combined with one another.
Avantageusement, la chambre forme un volume annulaire en contact avec le tube, fermé aux extrémités par les portées du boisseau en appui sur ce tube. Dans ce cas, avantageusement le segment d’étanchéité présente un diamètre intérieur fixé dans une gorge extérieure du tube, et un diamètre extérieur ajusté dans la chambre. Advantageously, the chamber forms an annular volume in contact with the tube, closed at the ends by the bearing surfaces of the plug resting on this tube. In this case, advantageously the sealing segment has an internal diameter fixed in an external groove of the tube, and an external diameter fitted in the chamber.
De plus, avantageusement le segment d’étanchéité présente un débit de fuite du fluide entre les deux volumes. In addition, the sealing segment advantageously has a fluid leakage rate between the two volumes.
Avantageusement, les positions avant et arrière du boisseau sont définis chacune par un jonc ajusté dans une gorge extérieure du tube. Advantageously, the front and rear positions of the plug are each defined by a ring fitted in an outer groove of the tube.
Avantageusement, les ressorts de rappel sont des ressorts hélicoïdaux ajustés dans un tube intérieur recevant le piston d’amortisseur. Advantageously, the return springs are helical springs fitted in an inner tube receiving the damper piston.
Avantageusement, des perçages du tube forment des fentes longitudinales partant de l’extrémité arrière de ce tube, présentant une largeur qui se réduit vers l’avant, les perçages arrière étant disposés axialement au niveau de ces fentes. Advantageously, the bores in the tube form longitudinal slots starting from the rear end of this tube, having a width which narrows towards the front, the rear bores being arranged axially at these slots.
Avantageusement, les perçages arrière présentent une section totale de passage du fluide supérieure à celle des passages avant. Advantageously, the rear bores have a total section of the passage of the fluid greater than that of the front passages.
Avantageusement, les perçages avant sont disposés en arrière de la fin de course du piston de butée. Advantageously, the front bores are arranged behind the end of stroke of the stop piston.
L’invention a aussi pour objet un véhicule automobile équipé d’amortisseurs hydrauliques de suspension, comportant des amortisseurs comprenant l’une quelconque des caractéristiques précédentes. The subject of the invention is also a motor vehicle equipped with hydraulic suspension dampers, comprising dampers comprising any of the preceding characteristics.
L’invention sera mieux comprise et d’autres caractéristiques et avantages apparaîtront plus clairement à la lecture de la description ci-après donnée à titre d’exemple, en référence aux dessins annexés dans lesquels : The invention will be better understood and other characteristics and advantages will emerge more clearly on reading the description given below, given by way of example, with reference to the accompanying drawings in which:
[Fig. 1 ] présente en coupe axiale la partie avant d’un amortisseur selon l’invention au repos, le véhicule étant à vide ; [Fig. 1] shows in axial section the front part of a shock absorber according to the invention at rest, the vehicle being unladen;
[Fig. 2] présente cet amortisseur en fonctionnement au début de la butée de fin de course ; [Fig. 2] shows this shock absorber in operation at the start of the end stop;
[Fig. 3] présente cet amortisseur en fonctionnement à la fin de la butée de fin de course ; [Fig. 3] shows this shock absorber in operation at the end of the end stop;
[Fig. 4] présente l’amortisseur au repos le véhicule étant chargé ; [Fig. 4] shows the shock absorber at rest with the vehicle loaded;
[Fig. 5] présente cet amortisseur en fonctionnement au début de la butée de fin de course ; et [Fig. 6] présente cet amortisseur en fonctionnement à la fin de la butée de fin de course. [Fig. 5] shows this shock absorber in operation at the start of the end stop; and [Fig. 6] shows this damper in operation at the end of the end stop.
La figure 1 présente un amortisseur télescopique comportant du côté avant indiqué par la flèche AV, un tube intérieur 4 disposé dans un tube extérieur 2 formant un corps, contenant un piston d’amortisseur 6 fixé sur une tige 8 séparant deux chambres hydrauliques pour réaliser l’amortissement principal du mouvement de la suspension. Le volume entre les tubes extérieur 2 et intérieur 4 contenant un gaz sous pression, reçoit le trop-plein de fluide venant de l’entrée de la tige 8 dans l’amortisseur lors de sa compression. Figure 1 shows a telescopic shock absorber comprising on the front side indicated by the arrow AV, an inner tube 4 disposed in an outer tube 2 forming a body, containing a shock absorber piston 6 fixed on a rod 8 separating two hydraulic chambers to achieve the main damping of the suspension movement. The volume between the outer 2 and inner 4 tubes containing a pressurized gas receives the overflow of fluid coming from the inlet of the rod 8 into the damper during its compression.
La tige 8 comporte une prolongation 10 en avant du piston d’amortisseur 6, comprenant à son extrémité avant un piston de butée 12 équipé sur son pourtour d’un joint d’étanchéité, qui rentre vers la fin de course de l’amortisseur dans un tube de butée 14 comprenant un fond d’extrémité avant 16 lié aux tubes extérieur 2 et intérieur 4. The rod 8 comprises an extension 10 in front of the shock absorber piston 6, comprising at its front end a stop piston 12 equipped on its periphery with a seal, which returns towards the end of stroke of the shock absorber in a stop tube 14 comprising a front end base 16 linked to the outer 2 and inner 4 tubes.
Le tube de butée 14 comporte des fentes longitudinales 20 partant de son extrémité arrière, couvrant près de la moitié de sa longueur, présentant une grande largeur à l’extrémité arrière, qui se réduit progressivement vers l’avant. Le tube de butée 14 comporte de plus deux séries de perçages, chacune étant alignée transversalement, comprenant des perçages arrière 22 disposés environ au premier tiers de l’extrémité avant des fentes 20, et des perçages avant 24 disposés près du fond avant 16. Stopper tube 14 has longitudinal slots 20 extending from its rear end, covering nearly half of its length, having a large width at the rear end, which gradually narrows forward. The stop tube 14 further comprises two series of bores, each aligned transversely, comprising rear bores 22 disposed approximately at the first third of the front end of the slots 20, and front bores 24 arranged near the front base 16.
Un boisseau 30 coulisse entre le tube de butée 14 et le tube intérieur 4, en permettant un passage libre du fluide de chaque côté grâce à des fentes longitudinales extérieures 32 formées autour de ce boisseau. A plug 30 slides between the stop tube 14 and the inner tube 4, allowing free passage of the fluid on each side by virtue of outer longitudinal slots 32 formed around this plug.
Le boisseau 30 comporte une portée annulaire avant 36 et une portée annulaire arrière 38 ajustées autour du tube de butée 14, formant un guidage comprenant une étanchéité sur ce tube. The plug 30 comprises a front annular seat 36 and a rear annular seat 38 fitted around the stop tube 14, forming a guide comprising a seal on this tube.
Le boisseau 30 peut coulisser suivant une course limitée de chaque côté par un jonc annulaire 34 engagé dans une gorge extérieure du tube de butée 14, entre une position arrière où sa portée arrière 38 ferme les perçages arrière 22, et une position avant où sa portée avant 36 ferme les perçages avant 24. Une chambre annulaire cylindrique 40 définie entre les deux portées 36, 38 du boisseau 30, en contact avec le tube de butée 14, reçoit à l’intérieur un segment annulaire 42 fixé dans une gorge extérieure de ce tube. Le segment 42 présente un contour extérieur ajusté sur la surface de la chambre annulaire, de manière à séparer axialement un volume avant et un volume arrière de cette chambre en permettant un petit débit de fuite entre elles. The plug 30 can slide along a limited stroke on each side by an annular ring 34 engaged in an outer groove of the stop tube 14, between a rear position where its rear seat 38 closes the rear holes 22, and a front position where its seat front 36 closes the front holes 24. A cylindrical annular chamber 40 defined between the two bearing surfaces 36, 38 of the plug 30, in contact with the stop tube 14, receives inside a annular segment 42 fixed in an outer groove of this tube. The segment 42 has an outer contour fitted to the surface of the annular chamber, so as to axially separate a front volume and a rear volume of this chamber, allowing a small leakage rate between them.
On obtient une dynamique lente de coulissement du boisseau 30 donné par le transfert de fluide entre les deux volumes de la chambre annulaire 40, qui est freiné par le débit de fuite autour du segment 42. A slow sliding dynamic of the plug 30 is obtained, given by the transfer of fluid between the two volumes of the annular chamber 40, which is slowed down by the leakage rate around the segment 42.
Le boisseau 30 est maintenu axialement entre deux ressorts hélicoïdaux de rappel ajustés dans le tube intérieur 4, comprenant un ressort de rappel avant 44 prenant appui sur le fond d’extrémité 16 pour rappeler le boisseau dans une position arrière en appui sur le jonc arrière 34, où les perçages arrière 22 sont fermés, les perçages avant 24 restant ouverts. The valve 30 is held axially between two helical return springs fitted in the inner tube 4, comprising a front return spring 44 bearing on the end base 16 to return the valve to a rear position resting on the rear ring 34 , where the rear holes 22 are closed, the front holes 24 remaining open.
Un ressort de rappel arrière 46 prend appui sur le piston d’amortisseur 6 pour rappeler le boisseau 30 dans une position avant en appui sur le jonc avant 34, avec les perçages avant 24 fermés et les perçages arrière 22 ouverts. A rear return spring 46 is supported on the damper piston 6 to return the valve 30 to a front position resting on the front ring 34, with the front holes 24 closed and the rear holes 22 open.
Les ressorts de rappel 44, 46 sont guidés dans le tube intérieur 4 ce qui assure un faible frottement et une absence de bruit. The return springs 44, 46 are guided in the inner tube 4 which ensures low friction and absence of noise.
En variante la chambre annulaire 40 peut être formée à l’extérieur du boisseau 30 contre le tube intérieur 4, avec un segment fixé à ce tube. Alternatively, the annular chamber 40 can be formed outside the plug 30 against the inner tube 4, with a segment attached to this tube.
Le véhicule étant à vide, le ressort de rappel avant 44 maintient le boisseau 30 dans sa position arrière, lors du roulage du véhicule des passages rapides de l’amortisseur sur la butée de fin de course, avec une fréquence d’environ un Hertz qui est celle de la suspension, ne modifient pas cette position du boisseau grâce à la dynamique lente de transfert dans sa chambre annulaire 40. With the vehicle unladen, the front return spring 44 maintains the plug 30 in its rear position, when the vehicle is rolling, the shock absorber passes quickly over the end stop, with a frequency of about one Hertz which is that of the suspension, do not modify this position of the valve thanks to the slow dynamics of transfer in its annular chamber 40.
La figure 2 présente l’amortisseur en début de sa fin de course, le piston de butée 12 étant entré dans le tube de butée 14. On a un freinage faible au début grâce au débit de fluide passant par une partie large des fentes 20, et par les perçages avant 24. FIG. 2 shows the shock absorber at the start of its end of travel, the stop piston 12 having entered the stop tube 14. There is weak braking at the start thanks to the flow of fluid passing through a wide part of the slots 20, and by the front holes 24.
La figure 3 présente l’amortisseur à la fin de sa fin de course, le piston de butée 12 étant arrivé au bout du tube de butée 14, avec un freinage progressif pendant toute cette course importante comprenant d’abord la fermeture des fentes 20. On a ensuite le fonctionnement avec uniquement les perçages avant 24, qui sont fermés un peu avant l’extrémité de la fin de course afin d’appliquer un freinage énergique à cette extrémité. FIG. 3 shows the shock absorber at the end of its end of stroke, the stop piston 12 having reached the end of the stop tube 14, with progressive braking throughout this important stroke including first of all the closing of the slots 20. We then have the operation with only the holes front 24, which are closed a little before the end of the limit switch in order to apply vigorous braking at this end.
On obtient un niveau de confort élevé avec un freinage progressif sur la course complète de la butée de fin de course. A high level of comfort is obtained with progressive braking over the entire travel of the end stop.
La figure 4 présente le véhicule chargé au repos, le piston de butée 12 arrivant juste au début du tube de butée 14. La pression du ressort de rappel arrière 46 pousse le boisseau 30 vers l’avant en comprimant le ressort de rappel avant 44, ce qui déplace ce boisseau en libérant les perçages arrière 22 et en fermant les perçages avant 24. FIG. 4 shows the loaded vehicle at rest, the stop piston 12 arriving just at the start of the stop tube 14. The pressure of the rear return spring 46 pushes the plug 30 forward by compressing the front return spring 44, which moves this bushel by freeing the rear holes 22 and closing the front holes 24.
Lors du roulage du véhicule avec des petites oscillations de la suspension, les perçages arrière 22 dégagés s’ajoutant aux fentes 20, la butée de fin de course ne freine quasiment pas l’amortisseur. Avantageusement les perçages arrière 22 présentent une section totale de passage supérieure à celle des perçages avant 24. L’amortissement se fait essentiellement par le fonctionnement du piston d’amortisseur 6. When driving the vehicle with small oscillations of the suspension, the rear holes 22 released in addition to the slots 20, the limit stop hardly brakes the shock absorber. Advantageously, the rear bores 22 have a total passage section greater than that of the front bores 24. Damping is effected mainly by the operation of the damper piston 6.
La figure 5 présente le véhicule avec l’amortisseur arrivant en début de fin de course, le piston de butée 12 venant de fermer les perçages arrière 22. Figure 5 shows the vehicle with the shock absorber arriving at the start of the end of travel, the stop piston 12 having just closed the rear holes 22.
On a alors un fonctionnement de la butée de fin de course sur une course réduite, allant jusqu’à la fin de course présentée figure 6, mais avec un freinage important grâce à la fermeture des perçages avant 24. We then have an operation of the end stop over a reduced stroke, going to the end of stroke shown in Figure 6, but with significant braking thanks to the closing of the front holes 24.
On obtient alors pour le véhicule en charge avec une assiette plus basse à la fois un amortissement normal pour les petites oscillations et un freinage important sur la course restante pour les grandes oscillations, ce qui assure le confort et la tenue de route. For the vehicle under load with a lower trim, both normal damping for small oscillations and significant braking over the remaining stroke for large oscillations is then obtained, which ensures comfort and road holding.
Après un déchargement du véhicule, le piston d’amortisseur 6 remonte en réduisant la pression sur le ressort de rappel arrière 46. Le boisseau 30 remonte aussi sous l’effet du ressort de rappel avant 44, avec une dynamique lente pour revenir dans la position d’origine présentée figure 1. After unloading the vehicle, the shock absorber piston 6 rises by reducing the pressure on the rear return spring 46. The valve 30 also rises under the effect of the front return spring 44, with a slow dynamic to return to the position. original shown in figure 1.
On obtient de manière simple et efficace, sans liaison avec l’extérieur ni système électrique, un réglage passif auto-adaptatif de la butée de fin de course. On notera que la butée de fin de course comporte des composants simples en nombre réduit, ce qui lui donne un coût modéré. A simple and efficient way, without any connection to the outside or an electrical system, is a self-adapting passive adjustment of the limit stop. It will be noted that the end stop has a reduced number of simple components, which gives it a moderate cost.

Claims

REVENDICATIONS
1. Amortisseur hydraulique comportant un piston d’amortisseur (6) se déplaçant axialement lors d’une compression dans une direction appelée avant (AV) qui est tournée vers un fond d’amortisseur (16), recevant vers l’avant une tige (10) comprenant à son extrémité un piston de butée (12) rentrant dans un tube fixe de butée de fin de course (14) présentant des perçages (20, 22, 24) qui freinent le fluide sortant de ce tube (14), caractérisé en ce qu’il comporte un boisseau (30) coulissant autour du tube (14), maintenu axialement entre un ressort de rappel avant (44) prenant appui sur le fond d’amortisseur (16) pour le rappeler dans une position arrière, et un ressort de rappel arrière (46) prenant appui sur le piston d’amortisseur (6) pour le rappeler dans une position avant, le boisseau (30) comprenant une portée arrière (38) fermant dans la position arrière des perçages arrière du tube (22) et une portée avant (36) fermant dans la position avant des perçages avant du tube (24), et comprenant une chambre (40) séparée axialement en deux volumes par un segment d’étanchéité (42) fixe. 1. Hydraulic shock absorber comprising a shock absorber piston (6) moving axially during compression in a direction called forward (AV) which is turned towards a shock absorber base (16), forwardly receiving a rod ( 10) comprising at its end a stop piston (12) entering a fixed end-of-stroke stop tube (14) having bores (20, 22, 24) which brake the fluid leaving this tube (14), characterized in that it comprises a plug (30) sliding around the tube (14), held axially between a front return spring (44) bearing on the shock absorber base (16) to return it to a rear position, and a rear return spring (46) bearing on the shock absorber piston (6) to return it to a front position, the plug (30) comprising a rear bearing surface (38) closing in the rear position of the rear holes of the tube ( 22) and a front bearing surface (36) closing in the front position of the front holes of the tube (24), and comprising by having a chamber (40) separated axially into two volumes by a fixed sealing segment (42).
2. Amortisseur selon la revendication 1 , caractérisé en ce que la chambre (40) forme un volume annulaire en contact avec le tube (14), fermé aux extrémités par les portées du boisseau (36, 38) en appui sur ce tube (14). 2. Shock absorber according to claim 1, characterized in that the chamber (40) forms an annular volume in contact with the tube (14), closed at the ends by the bearing surfaces of the valve (36, 38) resting on this tube (14) ).
3. Amortisseur selon la revendication 2, caractérisé en ce que le segment d’étanchéité (42) présente un diamètre intérieur fixé dans une gorge extérieure du tube (14), et un diamètre extérieur ajusté dans la chambre (40). 3. Shock absorber according to claim 2, characterized in that the sealing segment (42) has an internal diameter fixed in an external groove of the tube (14), and an external diameter fitted in the chamber (40).
4. Amortisseur selon la revendication 3, caractérisé en ce que le segment d’étanchéité (42) présente un débit de fuite du fluide entre les deux volumes. 4. Shock absorber according to claim 3, characterized in that the sealing segment (42) has a fluid leakage rate between the two volumes.
5. Amortisseur selon l’une quelconque des revendications précédentes, caractérisé en ce que les positions avant et arrière du boisseau (30) sont définis chacune par un jonc (34) ajusté dans une gorge extérieure du tube (14). 5. Shock absorber according to any one of the preceding claims, characterized in that the front and rear positions of the plug (30) are each defined by a ring (34) fitted in an outer groove of the tube (14).
6. Amortisseur selon l’une quelconque des revendications précédentes, caractérisé en ce que les ressorts de rappel (44, 46) sont des ressorts hélicoïdaux ajustés dans un tube intérieur (4) recevant le piston d’amortisseur (6). 6. Shock absorber according to any one of the preceding claims, characterized in that the return springs (44, 46) are helical springs fitted in an inner tube (4) receiving the shock absorber piston (6).
7. Amortisseur selon l’une quelconque des revendications précédentes, caractérisé en ce que des perçages (20) du tube (14) forment des fentes longitudinales partant de l’extrémité arrière de ce tube (14), présentant une largeur qui se réduit vers l’avant, les perçages arrière (22) étant disposés axialement au niveau de ces fentes (20). 7. Shock absorber according to any one of the preceding claims, characterized in that the bores (20) of the tube (14) form longitudinal slots starting from the rear end of this tube (14), having a width which is reduced towards the front, the rear bores (22) being disposed axially at the level of these slots (20).
8. Amortisseur selon l’une quelconque des revendications précédentes, caractérisé en ce que les perçages arrière (22) présentent une section totale de passage du fluide supérieure à celle des passages avant (24). 8. Shock absorber according to any one of the preceding claims, characterized in that the rear bores (22) have a total fluid passage section greater than that of the front passages (24).
9. Amortisseur selon l’une quelconque des revendications précédentes, caractérisé en ce que les perçages avant (24) sont disposés en arrière de la fin de course du piston de butée (12). 9. Shock absorber according to any one of the preceding claims, characterized in that the front bores (24) are disposed behind the end of stroke of the stop piston (12).
10. Véhicule automobile équipé d’amortisseurs hydrauliques de suspension, caractérisé en ce qu’il comporte des amortisseurs selon l’une quelconque des revendications précédentes. 10. Motor vehicle equipped with hydraulic suspension dampers, characterized in that it comprises dampers according to any one of the preceding claims.
PCT/FR2019/053255 2019-02-21 2019-12-20 Hydraulic shock absorber provided with a self-adjustable limit stop WO2020169893A1 (en)

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FR1901718A FR3093155B1 (en) 2019-02-21 2019-02-21 HYDRAULIC SHOCK ABSORBER EQUIPPED WITH A SELF-ADAPTABLE LIMIT STOP
FR1901718 2019-02-21

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3207270A (en) 1964-08-31 1965-09-21 Ellis Fluid Dynamics Corp Shock absorber including adjustable metering orifices
JPS56155139U (en) * 1980-04-21 1981-11-19
JPS58137143U (en) * 1982-03-12 1983-09-14 昭和製作所 Variable damping force hydraulic shock absorber
US20160025174A1 (en) * 2014-07-23 2016-01-28 Kyb Suspensions Europe, S.A. Variable load control system in a hydraulic device
US20160223045A1 (en) * 2015-02-03 2016-08-04 Tenneco Automotive Operating Company Inc. Secondary dampening assembly for shock absorber
FR3050000A1 (en) 2016-04-08 2017-10-13 Peugeot Citroen Automobiles Sa HYDRAULIC DAMPER EQUIPPED WITH AN ATTACK SHOCK HAVING AN ADJUSTABLE BRAKE LAW
EP3406931A1 (en) * 2017-05-24 2018-11-28 PSA Automobiles SA Self-adjusting hydraulic abutment for the end-of-travel of an oscillating movement

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3207270A (en) 1964-08-31 1965-09-21 Ellis Fluid Dynamics Corp Shock absorber including adjustable metering orifices
JPS56155139U (en) * 1980-04-21 1981-11-19
JPS58137143U (en) * 1982-03-12 1983-09-14 昭和製作所 Variable damping force hydraulic shock absorber
US20160025174A1 (en) * 2014-07-23 2016-01-28 Kyb Suspensions Europe, S.A. Variable load control system in a hydraulic device
US20160223045A1 (en) * 2015-02-03 2016-08-04 Tenneco Automotive Operating Company Inc. Secondary dampening assembly for shock absorber
FR3050000A1 (en) 2016-04-08 2017-10-13 Peugeot Citroen Automobiles Sa HYDRAULIC DAMPER EQUIPPED WITH AN ATTACK SHOCK HAVING AN ADJUSTABLE BRAKE LAW
EP3406931A1 (en) * 2017-05-24 2018-11-28 PSA Automobiles SA Self-adjusting hydraulic abutment for the end-of-travel of an oscillating movement

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FR3093155A1 (en) 2020-08-28

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