EP3948012A1 - Damper with travel limit stop provided with a pressure limit valve - Google Patents

Damper with travel limit stop provided with a pressure limit valve

Info

Publication number
EP3948012A1
EP3948012A1 EP20707731.4A EP20707731A EP3948012A1 EP 3948012 A1 EP3948012 A1 EP 3948012A1 EP 20707731 A EP20707731 A EP 20707731A EP 3948012 A1 EP3948012 A1 EP 3948012A1
Authority
EP
European Patent Office
Prior art keywords
stop
valve
piston
shock absorber
damper
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP20707731.4A
Other languages
German (de)
French (fr)
Inventor
Alan CAVAREC
Jean Marc ALLEGRE
Christophe Monteil
Frederic RIGUEL
Frederic Guingand
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Stellantis Auto SAS
Original Assignee
PSA Automobiles SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by PSA Automobiles SA filed Critical PSA Automobiles SA
Publication of EP3948012A1 publication Critical patent/EP3948012A1/en
Pending legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/48—Arrangements for providing different damping effects at different parts of the stroke
    • F16F9/49—Stops limiting fluid passage, e.g. hydraulic stops or elastomeric elements inside the cylinder which contribute to changes in fluid damping

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 may include a hydraulic end stop, which strongly slows down the movement before the end of travel to avoid an impact on a rigid stop.
  • a known type of hydraulic adjustable limit stop presented in particular by document US-A-3207270, comprises a rod receiving an axial thrust from a movement to be braked, driving a sliding piston 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 liner has a series of axially distributed holes, which are closed one after the other when the tube is introduced into this liner in order to increasingly slow down the transfer of fluid from the outer chamber formed around the liner. , to the bedroom in front of the piston inside the tube. Increasingly high braking is obtained from 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.
  • valve system with its spring is relatively complex to produce, which entails costs.
  • the present invention aims in particular to avoid these drawbacks of the prior art. It proposes for this purpose a hydraulic suspension damper comprising a damper piston sliding in an inner tube, which moves during compression of the damper in an axial direction called the forward direction, the damper piston extending through a stop piston returning at the end of the shock absorber stroke into a stop chamber equipped with bores, by pushing the fluid out of this stop chamber to brake the end of travel, this shock absorber being remarkable in that the stop chamber comprises a lateral bore arranged after a predefined stroke of the stop piston in the stop chamber, equipped with a valve for limiting the pressure in this stop chamber.
  • shock absorber for a lightly loaded vehicle, during small movements at the start of the end stop with high speeds the valve opens by limiting the pressure in the stop chamber. Once the drilling has been passed, the valve is neutralized, the limit stop works normally.
  • 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 valve comprises a ball pushed by a calibration spring to close the lateral bore.
  • the valve comprises a sleeve providing external guidance of the ball and of the calibration spring.
  • the stopper piston may be an annular piston comprising the bores, fitting around a stopper tube by closing the stopper chamber disposed around this stopper tube.
  • valve is advantageously fixed inside the stop tube.
  • valve socket can be fixed inside a tubular support fitted in the stop tube.
  • the predefined stroke is between 15 and 25mm.
  • the shock absorber comprises a valve calibration spring corresponding to an opening pressure of this valve giving a braking force of the stop piston of between 200 and 400daN.
  • the shock absorber comprises a valve calibration spring corresponding to an opening pressure of this valve given by a minimum compression speed of between 1.5 and 2.5 m / s.
  • the subject of the invention is also a motor vehicle comprising suspension shock absorbers comprising any of the preceding characteristics.
  • FIG. 1 shows in axial section the front part of a shock absorber according to the prior art, approaching the end stop;
  • FIG. 2 presents this shock absorber according to the prior art in the middle of the end stop
  • FIG. 3 shows the front part of a shock absorber according to the invention as it approaches the end stop
  • FIG. 4 is a graph showing examples of braking values for this shock absorber.
  • FIG. 1 shows a telescopic shock absorber working in compression along a main axis, towards a side called front by convention, indicated by the arrow AV.
  • the shock absorber has a cylindrical inner tube 2, containing a piston 4 fixed to the end of a shock absorber rod 20, sliding axially in this body with a seal to define a front chamber 6 and a rear chamber 22.
  • the piston 4 has reduced passages for the fluid 8 between the front chamber 6 and the rear chamber 22, which slow down its movement as a function of the direction and of the speed of passage of the fluid linked to the speed of the damper rod 20.
  • a compensation chamber forms an annular volume disposed between the inner tube 2 and an outer envelope, not shown, containing a pressurized gas, receiving the fluid discharged by the volume displaced during the entry of the damper rod 20 into the shock absorber when working in compression.
  • the piston 4 is extended on the front side by a circular liner 10 which before the end of the stroke fits around an end of stroke stop tube 12, closing an annular outer stop chamber 16 formed around this tube.
  • the stop tube 12 defining inside an inner chamber 26, is fixed by its front end to a cover 14 closing the front end of the inner tube 2.
  • the sleeve 10 has an outer annular boss 24 guiding it in the inner tube 2, and a series of axially aligned radial bores 18, which in the direction of the front have an increasingly larger diameter.
  • Figure 2 shows the advance of the liner 10 in the outer stop chamber 16 around the stop tube 12, the fluid from this outer chamber being pumped towards the inner chamber 26 through the bores 18 of calibrated section to achieve progressive braking of the advance of the rod of the shock absorber 20. The fluid then passes from the inner chamber 26 to the rear volume 22 of the piston 4 through its reduced passages 8.
  • the bores 18 of the sleeve 10 gradually close, which increasingly reduces the total section of the passage of the fluid from the stop chamber 16 to the inner chamber 26, and increases the braking force which becomes very important near the end of the stroke.
  • FIG. 3 shows a valve 34 fixed inside a tubular support 30 fitted in the stop tube 12, and wedged axially by a rear shoulder 32 bearing on the rear end of this stop tube.
  • the valve 34 comprises successively, starting radially from the outside, a radial bore 44 passing through both the stop tube 12 and the tubular support 30, a ball 36, then a calibrating helical spring working in compression 38, pressing on this ball outwards to close the radial hole.
  • valve 34 can operate in discharge when the pressure in the stop chamber 16 exceeds a threshold allowing the ball 36 to be moved backwards. compressing the setting spring 38.
  • Figure 4 shows the braking force F of the attack stop expressed in daN on the vertical axis, as a function of the stroke C expressed in mm from the start of the end stop, for different movement speeds piston 4 expressed in m / s.
  • the preset stroke C0 is 20mm.
  • the force F is very weak up to about 35mm of travel of the stop, then rises to about 200daN.
  • the force F rises quickly to reach 500daN at 20mm, then ends at around 700daN.
  • a speed value between 1.5 and 2.5m / s, and for a 20mm stroke the force F exceeds 300daN which is uncomfortable. This state is obtained, for example, when arriving on a retarder forming a boss on the road, which gives a high compression speed of the shock absorber with a low displacement.
  • the pressure-limiting valve 34 can be placed on other types of end-of-stroke stop, comprising for example a stop piston entering a stop tube equipped with bores, to perform the end-of-stroke braking. this stop piston.
  • a simple, efficient and economical way is obtained, with a simple valve 34 comprising very few components, an avoidance of the uncomfortable operating zone 52 limited by a predefined maximum stroke CO, and a minimum force FO of in particular between 200 and 400daN.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Fluid-Damping Devices (AREA)

Abstract

Hydraulic suspension damper comprising a damper piston which slides in an internal tube (2) and which is displaced during compression of the damper in an axial direction referred to as the forward direction, the damper piston being extended by a stop piston (10) which enters, at the end of travel of the damper, a stop chamber (16) which is provided with bores (18), forcing the fluid out of this stop chamber (16) in order to brake the travel end, the stop chamber (16) comprising a lateral bore (44) which is arranged after a predefined travel (C0) of the stop piston (10) in the stop chamber (16), and which is provided with a valve (34) for limiting the pressure in this stop chamber (16).

Description

DESCRIPTION DESCRIPTION
TITRE : AMORTISSEUR AVEC BUTEE DE FIN DE COURSE EQUIPEE TITLE: SHOCK ABSORBER WITH EQUIPPED LIMIT STOPS
D’UN CLAPET DE LIMITATION DE PRESSION A PRESSURE LIMITATION VALVE
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 freine fortement le mouvement avant la fin 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 may include a hydraulic end stop, which strongly slows down the movement before the end of travel 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-3207270, 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-A-3207270, comprises a rod receiving an axial thrust from a movement to be braked, driving a sliding piston 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 liner has a series of axially distributed holes, which are closed one after the other when the tube is introduced into this liner in order to increasingly slow down the transfer of fluid from the outer chamber formed around the liner. , to the bedroom in front of the piston inside the tube. Increasingly high braking is obtained from 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, 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. Toutefois ce type de butée comprenant un boisseau réglable commandé par la pression du ressort de poussée peut poser des problèmes, en particulier dans le cas d’un véhicule peu chargé qui n’a pas déplacé le boisseau, pour les déplacements de petite amplitude restant au début de la butée de fin de course, avec une vitesse élevée. Frequent pressing of the thrust spring on the plug with a loaded vehicle ends up lowering the plug which closes the bores in the stop tube by hardening the end stop more strongly. Safety is obtained by avoiding bottoming out of the suspension for this loaded vehicle. However, this type of stop comprising an adjustable valve controlled by the pressure of the thrust spring can pose problems, in particular in the case of a lightly loaded vehicle which has not moved the valve, for small amplitude movements remaining at start of the end stop at high speed.
Ce cas se produit notamment lors de l’arrivée sur un bossage transversal de la route formant un ralentisseur. On obtient alors un effort de freinage important qui dégrade le confort. This case occurs in particular when arriving at a transverse boss in the road forming a retarder. A significant braking force is then obtained which degrades comfort.
De plus le système de boisseau avec son ressort est relativement complexe à réaliser, ce qui entraîne des coûts. In addition, the valve system with its spring is relatively complex to produce, which entails costs.
La présente invention a notamment pour but d’éviter ces inconvénients de la technique antérieure. Elle propose à cet effet un amortisseur hydraulique de suspension comportant un piston d’amortisseur coulissant dans un tube intérieur, qui se déplace lors d’une compression de l’amortisseur dans une direction axiale appelée direction avant, le piston d'amortisseur se prolongeant par un piston de butée rentrant en fin de course de l’amortisseur dans une chambre de butée équipée de perçages, en refoulant le fluide hors de cette chambre de butée pour freiner la fin de course, cet amortisseur étant remarquable en ce que la chambre de butée comporte un perçage latéral disposé après une course prédéfinie du piston de butée dans la chambre de butée, équipé d’un clapet de limitation de la pression dans cette chambre de butée. The present invention aims in particular to avoid these drawbacks of the prior art. It proposes for this purpose a hydraulic suspension damper comprising a damper piston sliding in an inner tube, which moves during compression of the damper in an axial direction called the forward direction, the damper piston extending through a stop piston returning at the end of the shock absorber stroke into a stop chamber equipped with bores, by pushing the fluid out of this stop chamber to brake the end of travel, this shock absorber being remarkable in that the stop chamber comprises a lateral bore arranged after a predefined stroke of the stop piston in the stop chamber, equipped with a valve for limiting the pressure in this stop chamber.
Un avantage de cet amortisseur est que pour un véhicule peu chargé, lors des petits déplacements au début de la butée de fin de course avec des vitesses élevées le clapet s’ouvre en limitant la pression dans la chambre de butée. Une fois le perçage dépassé le clapet est neutralisé, la butée de fin de course fonctionne normalement. An advantage of this shock absorber is that for a lightly loaded vehicle, during small movements at the start of the end stop with high speeds the valve opens by limiting the pressure in the stop chamber. Once the drilling has been passed, the valve is neutralized, the limit stop works normally.
Pour les déplacements de grande amplitude avec une vitesse moins élevée, la pression ne monte pas trop au début de la fin de course, le clapet ne s’ouvre pas et la butée fonctionne normalement. On obtient de manière simple et économique une auto-adaptation automatique de la butée de fin de course qui assure le confort. For large amplitude movements at a slower speed, the pressure does not rise too much at the start of the limit switch, the valve does not open and the stopper operates normally. An automatic self-adaptation of the limit stop which ensures comfort is obtained in a simple and economical manner.
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, le clapet comporte une bille poussée par un ressort de tarage pour fermer le perçage latéral. Advantageously, the valve comprises a ball pushed by a calibration spring to close the lateral bore.
Dans ce cas, avantageusement, le clapet comporte une douille réalisant un guidage extérieur de la bille et du ressort de tarage. In this case, advantageously, the valve comprises a sleeve providing external guidance of the ball and of the calibration spring.
En particulier, le piston de butée peut être un piston annulaire comprenant les perçages, s’ajustant autour d’un tube de butée en fermant la chambre de butée disposée autour de ce tube de butée. In particular, the stopper piston may be an annular piston comprising the bores, fitting around a stopper tube by closing the stopper chamber disposed around this stopper tube.
Dans ce cas, avantageusement le clapet est fixé à l’intérieur du tube de butée. En particulier, la douille du clapet peut être fixée à l’intérieur d’un support tubulaire ajusté dans le tube de butée. Avantageusement, la course prédéfinie est comprise entre 15 et 25mm. In this case, the valve is advantageously fixed inside the stop tube. In particular, the valve socket can be fixed inside a tubular support fitted in the stop tube. Advantageously, the predefined stroke is between 15 and 25mm.
Avantageusement, l’amortisseur comporte un ressort de tarage du clapet correspondant à une pression d’ouverture de ce clapet donnant une force de freinage du piston de butée comprise entre 200 et 400daN. Advantageously, the shock absorber comprises a valve calibration spring corresponding to an opening pressure of this valve giving a braking force of the stop piston of between 200 and 400daN.
Avantageusement, l’amortisseur comporte un ressort de tarage du clapet correspondant à une pression d’ouverture de ce clapet donnée par une vitesse minimum de compression comprise entre 1 ,5 et 2,5m/s. Advantageously, the shock absorber comprises a valve calibration spring corresponding to an opening pressure of this valve given by a minimum compression speed of between 1.5 and 2.5 m / s.
L’invention a aussi pour objet un véhicule automobile comprenant des amortisseurs de suspension comportant l’une quelconque des caractéristiques précédentes. The subject of the invention is also a motor vehicle comprising suspension shock absorbers 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’art antérieur, à l’approche de la butée de fin de course ; [Fig. 1] shows in axial section the front part of a shock absorber according to the prior art, approaching the end stop;
[Fig. 2] présente cet amortisseur selon l’art antérieur au milieu de la butée de fin de course ; [Fig. 2] presents this shock absorber according to the prior art in the middle of the end stop;
[Fig. 3] présente la partie avant d’un amortisseur selon l’invention à l’approche de la butée de fin de course ; et [Fig. 3] shows the front part of a shock absorber according to the invention as it approaches the end stop; and
[Fig. 4] est un graphique donnant des exemples de valeurs de freinage pour cet amortisseur. [Fig. 4] is a graph showing examples of braking values for this shock absorber.
La figure 1 présente un amortisseur télescopique travaillant en compression suivant un axe principal, vers un côté appelé avant par convention, indiqué par la flèche AV. FIG. 1 shows a telescopic shock absorber working in compression along a main axis, towards a side called front by convention, indicated by the arrow AV.
L’amortisseur comporte un tube intérieur cylindrique 2, contenant un piston 4 fixé à l’extrémité d’une tige d’amortisseur 20, coulissant axialement dans ce corps avec une étanchéité pour délimiter une chambre avant 6 et une chambre arrière 22. The shock absorber has a cylindrical inner tube 2, containing a piston 4 fixed to the end of a shock absorber rod 20, sliding axially in this body with a seal to define a front chamber 6 and a rear chamber 22.
Le piston 4 comporte des passages réduits du fluide 8 entre la chambre avant 6 et la chambre arrière 22, qui freinent son mouvement en fonction de la direction et de la vitesse de passage du fluide liée à la vitesse de la tige d’amortisseur 20. Une chambre de compensation forme un volume annulaire disposé entre le tube intérieur 2 et une enveloppe extérieure non représentée, contenant un gaz sous pression, recevant le fluide refoulé par le volume déplacé lors de l’entrée de la tige d’amortisseur 20 dans l’amortisseur lors d’un travail en compression. The piston 4 has reduced passages for the fluid 8 between the front chamber 6 and the rear chamber 22, which slow down its movement as a function of the direction and of the speed of passage of the fluid linked to the speed of the damper rod 20. A compensation chamber forms an annular volume disposed between the inner tube 2 and an outer envelope, not shown, containing a pressurized gas, receiving the fluid discharged by the volume displaced during the entry of the damper rod 20 into the shock absorber when working in compression.
Le piston 4 se prolonge du côté avant par une chemise circulaire 10 qui avant la fin de course s’ajuste autour d’un tube de butée de fin de course 12, en fermant une chambre extérieure annulaire de butée 16 formée autour de ce tube. Le tube de butée 12 définissant à l’intérieur une chambre intérieure 26, est fixé par son extrémité avant à un couvercle 14 fermant l’extrémité avant du tube intérieur 2. The piston 4 is extended on the front side by a circular liner 10 which before the end of the stroke fits around an end of stroke stop tube 12, closing an annular outer stop chamber 16 formed around this tube. The stop tube 12 defining inside an inner chamber 26, is fixed by its front end to a cover 14 closing the front end of the inner tube 2.
La chemise 10 comporte un bossage annulaire extérieur 24 assurant son guidage dans le tube intérieur 2, et une série de perçages radiaux 18 alignés axialement, qui présentent en direction de l’avant un diamètre de plus en plus grand. The sleeve 10 has an outer annular boss 24 guiding it in the inner tube 2, and a series of axially aligned radial bores 18, which in the direction of the front have an increasingly larger diameter.
La figure 2 présente l’avance de la chemise 10 dans la chambre extérieure de butée 16 autour du tube de butée 12, le fluide de cette chambre extérieure étant refoulé vers la chambre intérieure 26 par les perçages 18 de section calibrée pour réaliser un freinage progressif de l’avance de la tige de l’amortisseur 20. Le fluide passe ensuite de la chambre intérieure 26 vers le volume arrière 22 du piston 4 par ses passages réduits 8. Figure 2 shows the advance of the liner 10 in the outer stop chamber 16 around the stop tube 12, the fluid from this outer chamber being pumped towards the inner chamber 26 through the bores 18 of calibrated section to achieve progressive braking of the advance of the rod of the shock absorber 20. The fluid then passes from the inner chamber 26 to the rear volume 22 of the piston 4 through its reduced passages 8.
Parallèlement en fonction de l’avance de la tige 20, les perçages 18 de la chemise 10 se ferment progressivement ce qui réduit de plus en plus la section totale de passage du fluide de la chambre de butée 16 vers la chambre intérieure 26, et augmente la force de freinage qui devient très importante près de la fin de course. At the same time as a function of the advance of the rod 20, the bores 18 of the sleeve 10 gradually close, which increasingly reduces the total section of the passage of the fluid from the stop chamber 16 to the inner chamber 26, and increases the braking force which becomes very important near the end of the stroke.
On obtient un freinage progressif de plus en plus important de la tige de l’amortisseur 20, que l’on détermine en ajustant les diamètres et les positions des perçages 18 de la chemise 10. Increasingly progressive braking is obtained on the rod of the shock absorber 20, which is determined by adjusting the diameters and the positions of the bores 18 of the sleeve 10.
La figure 3 présente un clapet 34 fixé à l’intérieur d’un support tubulaire 30 ajusté dans le tube de butée 12, et calé axialement par un épaulement arrière 32 prenant appui sur l’extrémité arrière de ce tube de butée. Le clapet 34 comporte successivement en partant radialement de l’extérieur, un perçage radial 44 traversant à la fois le tube de butée 12 et le support tubulaire 30, une bille 36, puis un ressort hélicoïdal de tarage travaillant en compression 38, pressant sur cette bille vers l’extérieur pour fermer le perçage radial. FIG. 3 shows a valve 34 fixed inside a tubular support 30 fitted in the stop tube 12, and wedged axially by a rear shoulder 32 bearing on the rear end of this stop tube. The valve 34 comprises successively, starting radially from the outside, a radial bore 44 passing through both the stop tube 12 and the tubular support 30, a ball 36, then a calibrating helical spring working in compression 38, pressing on this ball outwards to close the radial hole.
Une douille 40 fixée radialement dans le support tubulaire 30, formant un guidage du ressort 38 et de la bille 36, comporte vers le centre de l’amortisseur un épaulement intérieur comprenant un perçage central 42, qui retient l’extrémité de ce ressort pour lui permettre d’appliquer la pression sur la bille 36. A bush 40 fixed radially in the tubular support 30, forming a guide for the spring 38 and the ball 36, has towards the center of the shock absorber an inner shoulder comprising a central bore 42, which retains the end of this spring for it. allow pressure to be applied to the ball 36.
Avant la course prédéfinie C0 le déplacement de la chemise 10 autour du tube de butée 12 laisse le perçage radial 44 ouvert, le clapet 34 peut fonctionner en décharge quand la pression dans la chambre de butée 16 dépasse un seuil permettant de reculer la bille 36 en comprimant le ressort de tarage 38. Before the predefined stroke C0, the displacement of the sleeve 10 around the stop tube 12 leaves the radial bore 44 open, the valve 34 can operate in discharge when the pressure in the stop chamber 16 exceeds a threshold allowing the ball 36 to be moved backwards. compressing the setting spring 38.
Après la course prédéfinie C0 la chemise 10 dépasse le perçage radial 44 en le fermant, le fonctionnement de la butée de fin de course ne dépend plus du clapet 34. After the predefined stroke C0 the sleeve 10 goes beyond the radial bore 44 by closing it, the operation of the limit stop no longer depends on the valve 34.
La figure 4 présente la force F de freinage de la butée d’attaque exprimée en daN sur l’axe vertical, en fonction de la course C exprimée en mm à partir du début de la butée de fin de course, pour différentes vitesses de déplacement du piston 4 exprimées en m/s. La course prédéfinie C0 est de 20mm. Figure 4 shows the braking force F of the attack stop expressed in daN on the vertical axis, as a function of the stroke C expressed in mm from the start of the end stop, for different movement speeds piston 4 expressed in m / s. The preset stroke C0 is 20mm.
En particulier pour une petite vitesse de 0,1 m/s, la force F est très faible jusqu’à environ 35mm de course de la butée, puis monte ensuite à environ 200daN. A l’inverse pour une grande vitesse de 5 m/s, la force F monte rapidement pour atteindre 500daN à 20mm, puis termine à environ 700daN. Au-dessus d’une valeur de vitesse comprise entre 1 ,5 et 2,5m/s, et pour une course de 20mm, la force F dépasse 300daN ce qui est inconfortable. On obtient cet état par exemple lors de l’arrivée sur un ralentisseur formant un bossage sur la route, qui donne une grande vitesse de compression de l’amortisseur avec un faible déplacement. In particular for a low speed of 0.1 m / s, the force F is very weak up to about 35mm of travel of the stop, then rises to about 200daN. Conversely, for a high speed of 5 m / s, the force F rises quickly to reach 500daN at 20mm, then ends at around 700daN. Above a speed value between 1.5 and 2.5m / s, and for a 20mm stroke, the force F exceeds 300daN which is uncomfortable. This state is obtained, for example, when arriving on a retarder forming a boss on the road, which gives a high compression speed of the shock absorber with a low displacement.
Dans ce cas au-dessus de la force minimum F0 de 300daN, la pression dans la chambre de butée 16 est suffisamment importante pour ouvrir le clapet 34 en comprimant le ressort 38. On obtient une correction de courbe 50 qui limite la force F à 300daN jusqu’à la course prédéfinie CO. Après cette course prédéfinie CO la chemise 10 ferme le perçage 44 du clapet 34, les courbes reprennent leurs formes normales. In this case above the minimum force F0 of 300daN, the pressure in the stop chamber 16 is high enough to open the valve 34 by compressing the spring 38. A curve correction 50 is obtained which limits the force F at 300daN up to the preset stroke CO. After this predefined stroke CO the jacket 10 closes the bore 44 of the valve 34, the curves resume their normal shapes.
En variante on peut disposer le clapet de limitation de pression 34 sur d’autres types de butée de fin de course, comprenant par exemple un piston de butée rentrant dans un tube de butée équipé de perçages, pour réaliser le freinage de fin de course de ce piston de butée. As a variant, the pressure-limiting valve 34 can be placed on other types of end-of-stroke stop, comprising for example a stop piston entering a stop tube equipped with bores, to perform the end-of-stroke braking. this stop piston.
On obtient de manière simple, efficace et économique, avec un simple clapet 34 comprenant très peu de composants, un évitement de la zone de fonctionnement inconfortable 52 limitée par un maximum de course prédéfinie CO, et un minimum de force FO compris notamment entre 200 et 400daN. A simple, efficient and economical way is obtained, with a simple valve 34 comprising very few components, an avoidance of the uncomfortable operating zone 52 limited by a predefined maximum stroke CO, and a minimum force FO of in particular between 200 and 400daN.

Claims

REVENDICATIONS
1. Amortisseur hydraulique de suspension comportant un piston d’amortisseur (4) coulissant dans un tube intérieur (2), qui se déplace lors d’une compression de l’amortisseur dans une direction axiale appelée direction avant (AV), le piston d'amortisseur (4) se prolongeant par un piston de butée (10) rentrant en fin de course de l’amortisseur dans une chambre de butée (16) équipée de perçages (18), en refoulant le fluide hors de cette chambre de butée (16) pour freiner la fin de course, la chambre de butée (16) comportant un perçage latéral (44) disposé après une course prédéfinie (CO) du piston de butée (10) dans la chambre de butée (16), équipé d’un clapet (34) de limitation de la pression dans cette chambre de butée (16), caractérisé en ce que le piston de butée (10) est un piston annulaire comprenant lesdits perçages (18), s’ajustant autour d’un tube de butée (12) en fermant la chambre de butée (16) disposée autour de ce tube de butée (12). 1. A hydraulic suspension damper comprising a damper piston (4) sliding in an inner tube (2), which moves during compression of the damper in an axial direction called the forward direction (AV), the piston d 'shock absorber (4) extending by a stop piston (10) returning at the end of the shock absorber's stroke into a stop chamber (16) equipped with bores (18), by pushing the fluid out of this stop chamber ( 16) to brake the end of stroke, the stop chamber (16) comprising a lateral bore (44) arranged after a predefined stroke (CO) of the stop piston (10) in the stop chamber (16), equipped with a valve (34) for limiting the pressure in this stop chamber (16), characterized in that the stop piston (10) is an annular piston comprising said bores (18), fitting around a pressure tube stopper (12) by closing the stopper chamber (16) arranged around this stopper tube (12).
2. Amortisseur selon la revendication 1 , caractérisé en ce que le clapet (34) comporte une bille (36) poussée par un ressort de tarage (38) pour fermer le perçage latéral (44). 2. Shock absorber according to claim 1, characterized in that the valve (34) comprises a ball (36) pushed by a calibration spring (38) to close the lateral bore (44).
3. Amortisseur selon la revendication 2, caractérisé en ce que le clapet (34) comporte une douille (40) réalisant un guidage extérieur de la bille (36) et du ressort de tarage (38). 3. Shock absorber according to claim 2, characterized in that the valve (34) comprises a bush (40) providing an external guide of the ball (36) and of the calibration spring (38).
4. Amortisseur selon l’une quelconque des revendications précédentes, caractérisé en ce que le clapet (34) est fixé à l’intérieur du tube de butée (12). 4. Shock absorber according to any one of the preceding claims, characterized in that the valve (34) is fixed inside the stop tube (12).
5. Amortisseur selon les revendications 3 et l’une quelconque des autres revendications, caractérisé en ce que la douille (40) du clapet (34) est fixée à l’intérieur d’un support tubulaire (30) ajusté dans le tube de butée (12). 5. Shock absorber according to claims 3 and any one of the other claims, characterized in that the bush (40) of the valve (34) is fixed inside a tubular support (30) fitted in the stop tube. (12).
6. Amortisseur selon l’une quelconque des revendications précédentes, caractérisé en ce que la course prédéfinie (C0) est comprise entre 15 et 25mm. 6. Shock absorber according to any one of the preceding claims, characterized in that the predefined stroke (C0) is between 15 and 25mm.
7. Amortisseur selon l’une quelconque des revendications précédentes, caractérisé en ce qu’il comporte un ressort de tarage (38) du clapet (34) correspondant à une pression d’ouverture de ce clapet (34) donnant une force de freinage du piston de butée (10) comprise entre 200 et 400daN. 7. A damper according to any one of the preceding claims, characterized in that it comprises a calibration spring (38) of the valve (34) corresponding to an opening pressure of this valve (34) giving a braking force of the valve. stop piston (10) between 200 and 400daN.
8. Amortisseur selon l’une quelconque des revendications précédentes, caractérisé en ce qu’il comporte un ressort de tarage (38) du clapet (34) correspondant à une pression d’ouverture de ce clapet (34) donnée par une vitesse minimum de compression comprise entre 1 ,5 et 2,5m/s. 8. A damper according to any one of the preceding claims, characterized in that it comprises a calibration spring (38) of the valve (34) corresponding to an opening pressure of this valve (34) given by a minimum speed of compression between 1, 5 and 2.5m / s.
9. Véhicule automobile comprenant des amortisseurs de suspension, caractérisé en ce qu’il comporte des amortisseurs selon l’une quelconque des revendications précédentes. 9. Motor vehicle comprising suspension shock absorbers, characterized in that it comprises shock absorbers according to any one of the preceding claims.
EP20707731.4A 2019-03-28 2020-02-10 Damper with travel limit stop provided with a pressure limit valve Pending EP3948012A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1903228A FR3094434B1 (en) 2019-03-28 2019-03-28 SHOCK ABSORBER WITH LIMIT STOPS EQUIPPED WITH A PRESSURE LIMITATION VALVE
PCT/FR2020/050224 WO2020193883A1 (en) 2019-03-28 2020-02-10 Damper with travel limit stop provided with a pressure limit valve

Publications (1)

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EP3948012A1 true EP3948012A1 (en) 2022-02-09

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Application Number Title Priority Date Filing Date
EP20707731.4A Pending EP3948012A1 (en) 2019-03-28 2020-02-10 Damper with travel limit stop provided with a pressure limit valve

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EP (1) EP3948012A1 (en)
CN (1) CN113646557B (en)
FR (1) FR3094434B1 (en)
WO (1) WO2020193883A1 (en)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL132645C (en) 1964-08-31 1900-01-01
US4026533A (en) * 1975-08-29 1977-05-31 Hennells Ransom J Shock absorber with conical control elements
DE102010023870A1 (en) * 2010-06-15 2011-02-10 Daimler Ag Pneumatic spring damping device, particularly two-tube pneumatic spring damping device for motor vehicle, has compensation chamber with throttle device
FR3050000B1 (en) * 2016-04-08 2018-09-07 Peugeot Citroen Automobiles Sa HYDRAULIC DAMPER EQUIPPED WITH AN ATTACK ROCK HAVING AN ADJUSTABLE BRAKING LAW
FR3050496B1 (en) * 2016-04-25 2018-09-07 Peugeot Citroen Automobiles Sa HYDRAULIC SUSPENSION SYSTEM OF A VEHICLE
CN107013623B (en) * 2016-05-13 2019-01-25 北京京西重工有限公司 Hydraulic damper for vehicle
FR3066796B1 (en) * 2017-05-24 2019-06-21 Peugeot Citroen Automobiles Sa AUTO-ADJUSTABLE HYDRAULIC STOP FOR THE END OF THE RACE OF AN OSCILLATING MOVEMENT

Also Published As

Publication number Publication date
WO2020193883A1 (en) 2020-10-01
CN113646557A (en) 2021-11-12
FR3094434B1 (en) 2021-11-19
CN113646557B (en) 2023-12-01
FR3094434A1 (en) 2020-10-02

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