WO1989009891A1 - Twin-pipe shock absorber - Google Patents

Twin-pipe shock absorber Download PDF

Info

Publication number
WO1989009891A1
WO1989009891A1 PCT/NL1989/000016 NL8900016W WO8909891A1 WO 1989009891 A1 WO1989009891 A1 WO 1989009891A1 NL 8900016 W NL8900016 W NL 8900016W WO 8909891 A1 WO8909891 A1 WO 8909891A1
Authority
WO
WIPO (PCT)
Prior art keywords
piston
shock absorber
valve
working cylinder
passage
Prior art date
Application number
PCT/NL1989/000016
Other languages
French (fr)
Inventor
Cornelis De Kock
Original Assignee
Koni B.V.
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 Koni B.V. filed Critical Koni B.V.
Priority to US08/113,888 priority Critical patent/US5423402A/en
Priority to DE8989904258T priority patent/DE68900319D1/en
Priority to AT89904258T priority patent/ATE68247T1/en
Publication of WO1989009891A1 publication Critical patent/WO1989009891A1/en
Priority to US08/396,312 priority patent/US5467852A/en

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
    • F16F9/486—Arrangements for providing different damping effects at different parts of the stroke comprising a pin or stem co-operating with an aperture, e.g. a cylinder-mounted stem co-operating with a hollow piston rod
    • 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
    • F16F9/44—Means on or in the damper for manual or non-automatic adjustment; such means combined with temperature correction
    • F16F9/46—Means on or in the damper for manual or non-automatic adjustment; such means combined with temperature correction allowing control from a distance, i.e. location of means for control input being remote from site of valves, e.g. on damper external wall
    • 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
    • F16F9/44—Means on or in the damper for manual or non-automatic adjustment; such means combined with temperature correction
    • F16F9/46—Means on or in the damper for manual or non-automatic adjustment; such means combined with temperature correction allowing control from a distance, i.e. location of means for control input being remote from site of valves, e.g. on damper external wall
    • F16F9/465—Means on or in the damper for manual or non-automatic adjustment; such means combined with temperature correction allowing control from a distance, i.e. location of means for control input being remote from site of valves, e.g. on damper external wall using servo control, the servo pressure being created by the flow of damping fluid, e.g. controlling pressure in a chamber downstream of a pilot passage
    • 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
    • F16F9/50—Special 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
    • F16F9/504—Inertia, i.e. acceleration,-sensitive means

Definitions

  • the invention relates to a twin-pipe shock absorber, com ⁇ prising a working cylinder, a piston which is movable in said cylinder and has a passage and upstream valve, an external pipe fitted round the working cylinder, an oil tank between working cylinder and external pipe, a disc shutting off the working cylin- der and having a passage and an upstream valve, and a damper valve.
  • shock absorbers are known.
  • the damper valve in them is located either in the piston rod guide or in a separate bypass.
  • a disadvantage is that the shock absorption is the same at all frequencies of movement of the unsprung wheel guide part. At high frequencies this is very disturbing.
  • the object of the invention is to eli ⁇ minate this disadvantage and produce a shock absorber of the type mentioned in the preamble, in which the shock absorption can be adapted very rapidly to the frequency of movement of the unsprung wheel guide part.
  • the above twin-pipe shock absor ⁇ ber is characterized in that a central pipe extends through the piston and with its bottom end projects through said disc, said damper valve is disposed at the bottom end of said central pipe, and regulation means are present to regulate the damping exerted by the damper valve depending at least on the frequency at which the working cylinder vibrates.
  • shock absorbers which have damping adapted to frequency have two damper valves and two regu- lation systems. This makes those designs expensive and complex.
  • GB-A-2, 159,604 discloses a twin-pipe shock absorber having an electromagnetically controlled axially displaceable control tube in the interior of the piston rod.
  • the damper valve at the bottom end of the control tube cannot be regulated depending on the frequency at which the working cylinder vibrates.
  • FR-A-2,560,325 discloses a twin-pipe shock absorber having an electronically controllable damping valve in the connec ⁇ tion between the oil tank and the space underneath the piston. However, there is no central pipe extending through the piston and with its bottom end projecting through a disc shutting off the working cylinder.
  • the valve body of the damper valve will be disposed on or form part of an exciting element which moves up and down and has a narrow oil passage, such throttling means being capable of regulat ⁇ ing the oil pressure under said exciting element.
  • a finer regulation is, however, possible if provision is made below the exciting element for a throttle plate fixed to one or more coils which are placed in the field of at least one perma ⁇ nent magnet, it being possible to move the throttle plate up and down through more or less exciting of the coils, and provision being made between the throttle plate and the exciting element for an oil chamber having an oil throughflow spout which can be shut off to a greater or lesser extent by the throttle plate.
  • the exciting element can be a piston which is displaceable in a cylinder.
  • the leakage occurring between cylinder and exciting piston can cause problems in accuracy. It may therefore be prefer ⁇ able for the exciting element to be suspended in resilient mem ⁇ branes. If a spring acts upon the throttle plate, fitting tolerances can be eliminated.
  • the invention also relates to a vehicle provided with a shock absorber of the above-mentioned type, in which a throttle plate fixed to one or more coils is disposed below the exciting element.
  • the coils have an electrical connection to a regulation system which is in turn connected to sensors for measuring different movements of the vehicle, and which can give signals to the coils depending on the movements measured.
  • Figs. 1, 2 and 3 show respectively three embodiments of shock absorbers according to the invention.
  • Fig. 4 shows the bottom end of the embodiment according to ' Fig. 3, on a larger scale.
  • the shock absorber shown in Fig. 1 comprises a working cylin ⁇ der 1 designed as an internal pipe, an external pipe 2, a tank 3 located between the working cylinder 1 and the external pipe 2, a piston 4 which is displaceable in the working cylinder 1 , a hollow piston rod 5 connected to the sprung part of a wheel suspension part, a cover 6 shutting off the working cylinder and the tank at the top and also forming guidance for the piston rod, a disc 7 shutting off the working cylinder 1 a short distance above its bottom end, and a bottom plate 8 which shuts off the working cylin ⁇ der 1 and the external pipe 2 and is provided with a fastening eye 9 for fastening the shock absorber to the unsprung part of the wheel guide.
  • the piston rod 5 has apertures 11 which connect the space above the piston to the interior of the piston rod.
  • the top end of the central pipe 10 is some distance above the apertures 11.
  • the piston 4 is provided with a cylin- drical valve housing 12, a valve seat 13, and a valve body 14 which is pressed by a spring 15 on the seat 13.
  • the parts 12 to 15 form an upstream valve.
  • the disc 7 contains passages 16 which are provided with a spring-loaded upstream valve 17 on the top side.
  • an exciting piston 19 which is displace ⁇ able up and down in a cylinder 18, and on which the resilient valve body 20 of the damper valve is fitted. This valve body 20 contacts a seat at the bottom side of the disc 7 when the damper valve is in the closed position.
  • the exciting piston 19 contains a narrow duct 21 (for re ⁇ striction) which connects the space above and below the piston 19.
  • the pressure above and below the piston 19 can be balanced by means of this duct.
  • a solid, relatively heavy piston 23 (mass inertia piston) which is displaceable up and down in a cylinder 22 is disposed below the exciting piston 19. This heavy piston is retained between two springs 24, 25.
  • the spring 25 presses a valve body 26 against a seat formed on the cover of the cylinder 22.
  • An aperture 27 is provided in this cylinder cover.
  • the spring 24 rests against the bottom plate 8.
  • the mass inertia piston 23 has a passage 28 with upstream valve 29.
  • the oil tank 3 is connected by means of apertures 30 to the space below the disc 7.
  • the shock absorber works as follows:
  • the upstream valve 13, 14, 15 of the piston 4 causes negligible damping; the damping action is produced by the damper valve 7, 20 on the bottom side of the disc 7.
  • the size of the damping is determined by the system 18, 19, 22 to 29 situated below the valve body 20, in particular by the combination of mass inertia piston 23 and the springs 24, 25, the so-called mass spring system.
  • This system is designed for the actual frequen ⁇ cy of the non sprung mass (wheel, hub, disc brake, wheel guide part).
  • the valve body 26 comes away from its seat, so that the pressure below the exciting piston 19 is reduced or falls off.
  • the valve body 20 of the damper valve is pressed on its seat with little or no pres ⁇ sure, so that the damping action is very slight. This is restored after the piston 23 is returned to its original place by the springs 24, 25, and the valve body 26 goes onto its seat.
  • the oil flow through the narrow duct 20 can then pressurize the space below the exciting element 19.
  • the mass inertia piston 23 displaces oil when it moves, so that the recoil movement is damped.
  • the damping of the shock absorber can decrease to zero at high frequencies of the movement of the unsprung mass. The movements of low frequency and great amplitude can be damped in the optimum manner.
  • corresponding parts are given the same reference numbers.
  • This embodiment differs from that of Fig. 1 in that the mass spring system is replaced by an electromagnetic system.
  • the exciting element 19 is also a damper valve body.
  • the said electromagnetic system comprises a permanent magnet 31, which is fixed to the cylinder 18, and a suspended electrical coil 32 with horizontal choke plate 33. The attracting action of the permanent magnet on the elec ⁇ trically excited coil causes the choke plate 33 to be pressed against a seat surrounding an outflow port 34 in the bottom of the cylinder 18.
  • a spring 35 which presses the piston 18 against a seat at the bottom side of the disc 7 is active between the bottom of the cylinder 18 and the exciting piston 19.
  • the coil 31 is electrically connected to earth at one side, and at the other is connected by means of a wire 37 to a connecting element 36 which can be connected to an electronic control system.
  • the exciting of the coil 31 will result in a reduction or enlarge ⁇ ment of the gap between the choke plate 33 and the duct 34.
  • a release in pressure occurs below the exciting piston 19, with the result that the piston is not pressed as hard against the damper valve seat, so that there is less damping.
  • a reduction in the width of the gap results in greater damping.
  • the said electronic control system is connected to sensors which pass on information to the system on any change in the steer ⁇ ing angle per second, the speed of travel, the horizontal and vertical, lateral and transversal speed, the height of travel etc.
  • This system excites the coil 34, so that a lower or higher damping level is selected.
  • the switching speed is extremely high.
  • the damper valve reacts to slight movements in the regulating coil. As in Fig. 1 , the damping can be switched off fully or partially if there are disturbing high frequencies in the movement of the un ⁇ sprung part of the wheel guide.
  • a disadvantage of the invention according to Fig. 2 can be that leakage between the exciting piston 19 and the cylinder 18 is not constant. Seals cannot be used, due to the additional friction.
  • the embodiment according to Figs. 3 and 4 does not have these disadvantages.
  • corresponding parts are given the same reference numbers.
  • the exciting element 19 is free from the walls of the cylinder 8, 18 and is suspended in resilient plates 49.
  • the valve body 17 of the damper valve also consists of resilient plates. There is no risk of leaking; oil can pass through the exciting element only via duct 21. The regulating process can be accurate; the sensitivity is great. Provision is made below the throttle plate 23 for another leaf spring 41 which holds the throttle plate in the de-energized position.
  • the damping takes place on both the outgoing and the ingoing stroke by means of the same damper valve, whose damping action is regulated mechanically or electromagnetically in such a way that at high frequency of the movement of the unsprung part of the wheel guide it is reduced to a minimum, while at low frequency the normal damping action is achieved.
  • the embodiments described lead to very rapid adaptation of the damping action to the said frequency.
  • the piston 4 in the working cylinder 1 is simple in design and has only one upstream valve which lies round the central pipe in such a way that it gives a dynamic seal. Concentrating the damping in a single regulating element is a great practical advantage.
  • various additions and modifications are possible within the scope of the invention.
  • the duct 34 can contain a cylin ⁇ drical shaft with flat side or a tapering shaft which rests on the choke plate 33 and determines the dimensions of the passage accu ⁇ rately when the choke plate is not resting on its seat.

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

Abstract

A twin-pipe shock absorber comprises a working cylinder (1), a piston (4) which is movable in the cylinder and has a passage and upstream valve (13, 14, 15). Round the working cylinder an external pipe (2) is fitted and an oil tank (3) is present between the working cylinder and the external pipe. The working cylinder is shut off by a disc (7) having a passage (16) and an upstream valve (17) positioned near said passage. Further the absorber is provided with a damper valve. To produce a shock absorber in which the shock absorption can be adapted very rapidly to the frequency of movement of the unsprung wheel guide part a central pipe (10) extends through the piston (4) and with its bottom end projects through said disc (7). The damper valve is disposed at the bottom end of said central pipe (10), and regulation means are present to regulate the damping exerted by the damper valve depending at least on the frequency at which the working cylinder vibrates.

Description

Short title: Twin-pipe shock absorber.
The invention relates to a twin-pipe shock absorber, com¬ prising a working cylinder, a piston which is movable in said cylinder and has a passage and upstream valve, an external pipe fitted round the working cylinder, an oil tank between working cylinder and external pipe, a disc shutting off the working cylin- der and having a passage and an upstream valve, and a damper valve.
Such shock absorbers are known. The damper valve in them is located either in the piston rod guide or in a separate bypass.
The oil flow passes through the same damper valve both on the ingoing and on the outgoing stroke of the piston. A disadvantage is that the shock absorption is the same at all frequencies of movement of the unsprung wheel guide part. At high frequencies this is very disturbing. The object of the invention is to eli¬ minate this disadvantage and produce a shock absorber of the type mentioned in the preamble, in which the shock absorption can be adapted very rapidly to the frequency of movement of the unsprung wheel guide part.
According to the invention, the above twin-pipe shock absor¬ ber is characterized in that a central pipe extends through the piston and with its bottom end projects through said disc, said damper valve is disposed at the bottom end of said central pipe, and regulation means are present to regulate the damping exerted by the damper valve depending at least on the frequency at which the working cylinder vibrates.
It is of essential importance that the oil flow on the in- going and outgoing stroke of the piston is conveyed through the central pipe to one single damper valve, and that the damping of this valve can be set rapidly. The piston of the shock absorber and the guide of the piston are simple in design: there is only one upstream valve, which can be placed round the central pipe in such a way that it seals dynamically.
It is pointed out that known shock absorbers which have damping adapted to frequency have two damper valves and two regu- lation systems. This makes those designs expensive and complex.
GB-A-2, 159,604 discloses a twin-pipe shock absorber having an electromagnetically controlled axially displaceable control tube in the interior of the piston rod. The damper valve at the bottom end of the control tube cannot be regulated depending on the frequency at which the working cylinder vibrates.
Further FR-A-2,560,325 discloses a twin-pipe shock absorber having an electronically controllable damping valve in the connec¬ tion between the oil tank and the space underneath the piston. However, there is no central pipe extending through the piston and with its bottom end projecting through a disc shutting off the working cylinder.
The valve body of the damper valve will be disposed on or form part of an exciting element which moves up and down and has a narrow oil passage, such throttling means being capable of regulat¬ ing the oil pressure under said exciting element.
In order to produce the regulation by mechanical means, provision is made below the exciting element for a mass inertia piston between two springs or spring systems, in which piston there is a passage which is provided with an upstream valve and connects the space above and below the piston, there being above the piston an oil passage with valve which can be opened when the oil pressure is raised above the piston, in order to reduce the pressure below the exciting element. A finer regulation is, however, possible if provision is made below the exciting element for a throttle plate fixed to one or more coils which are placed in the field of at least one perma¬ nent magnet, it being possible to move the throttle plate up and down through more or less exciting of the coils, and provision being made between the throttle plate and the exciting element for an oil chamber having an oil throughflow spout which can be shut off to a greater or lesser extent by the throttle plate.
The exciting element can be a piston which is displaceable in a cylinder. The leakage occurring between cylinder and exciting piston can cause problems in accuracy. It may therefore be prefer¬ able for the exciting element to be suspended in resilient mem¬ branes. If a spring acts upon the throttle plate, fitting tolerances can be eliminated.
The invention also relates to a vehicle provided with a shock absorber of the above-mentioned type, in which a throttle plate fixed to one or more coils is disposed below the exciting element. According to the invention, the coils have an electrical connection to a regulation system which is in turn connected to sensors for measuring different movements of the vehicle, and which can give signals to the coils depending on the movements measured. The invention will now be explained in greater detail with reference to the figures, in which a number of embodiments are shown in longitudinal section.
Figs. 1, 2 and 3 show respectively three embodiments of shock absorbers according to the invention. Fig. 4 shows the bottom end of the embodiment according to ' Fig. 3, on a larger scale.
The shock absorber shown in Fig. 1 comprises a working cylin¬ der 1 designed as an internal pipe, an external pipe 2, a tank 3 located between the working cylinder 1 and the external pipe 2, a piston 4 which is displaceable in the working cylinder 1 , a hollow piston rod 5 connected to the sprung part of a wheel suspension part, a cover 6 shutting off the working cylinder and the tank at the top and also forming guidance for the piston rod, a disc 7 shutting off the working cylinder 1 a short distance above its bottom end, and a bottom plate 8 which shuts off the working cylin¬ der 1 and the external pipe 2 and is provided with a fastening eye 9 for fastening the shock absorber to the unsprung part of the wheel guide.
A central pipe 10, projecting with its bottom end through the disc 7, extends through the piston 4.
Just above the piston 4, the piston rod 5 has apertures 11 which connect the space above the piston to the interior of the piston rod. The top end of the central pipe 10 is some distance above the apertures 11. The piston 4 is provided with a cylin- drical valve housing 12, a valve seat 13, and a valve body 14 which is pressed by a spring 15 on the seat 13. The parts 12 to 15 form an upstream valve. The disc 7 contains passages 16 which are provided with a spring-loaded upstream valve 17 on the top side.
Below the disc 7 is an exciting piston 19 which is displace¬ able up and down in a cylinder 18, and on which the resilient valve body 20 of the damper valve is fitted. This valve body 20 contacts a seat at the bottom side of the disc 7 when the damper valve is in the closed position.
The exciting piston 19 contains a narrow duct 21 (for re¬ striction) which connects the space above and below the piston 19. The pressure above and below the piston 19 can be balanced by means of this duct.
A solid, relatively heavy piston 23 (mass inertia piston) which is displaceable up and down in a cylinder 22 is disposed below the exciting piston 19. This heavy piston is retained between two springs 24, 25. The spring 25 presses a valve body 26 against a seat formed on the cover of the cylinder 22. An aperture 27 is provided in this cylinder cover. The spring 24 rests against the bottom plate 8. The mass inertia piston 23 has a passage 28 with upstream valve 29. The oil tank 3 is connected by means of apertures 30 to the space below the disc 7.
The shock absorber works as follows:
On the outgoing stroke (the piston 4 moves upwards) the oil above the piston 4 is pressed through the apertures 11 into the hollow piston rod 5 and comes to rest in the central pipe 10. Near the foot of this pipe 10 the oil flows through the damper valve to the ducts 16 and via the upstream valve 17 into the space below the piston 4. On the ingoing stroke (piston 4 moves downwards) the oil lying below the piston 4 will flow through the upstream valve 13, 14, 15 to the increasing space above the piston 4. An oil volume corresponding to the volume of the piston rod 5 penetrating the working cylinder 1 also flows through the central pipe 10 to the damper valve 7, 20 and after passing through it goes into the tank
3 through the apertures 30. The upstream valve 13, 14, 15 of the piston 4 causes negligible damping; the damping action is produced by the damper valve 7, 20 on the bottom side of the disc 7. The size of the damping is determined by the system 18, 19, 22 to 29 situated below the valve body 20, in particular by the combination of mass inertia piston 23 and the springs 24, 25, the so-called mass spring system. This system is designed for the actual frequen¬ cy of the non sprung mass (wheel, hub, disc brake, wheel guide part). When the wheel is flung up, the piston 23 remains behind, while oil flows via the ball valve 29 and the passage 28 from the space below the piston 23 to the space above the piston 23. The valve body 26 comes away from its seat, so that the pressure below the exciting piston 19 is reduced or falls off. The valve body 20 of the damper valve is pressed on its seat with little or no pres¬ sure, so that the damping action is very slight. This is restored after the piston 23 is returned to its original place by the springs 24, 25, and the valve body 26 goes onto its seat. The oil flow through the narrow duct 20 can then pressurize the space below the exciting element 19.
The mass inertia piston 23 displaces oil when it moves, so that the recoil movement is damped. With a suitable selection of the characteristics of the springs 24, 25 and the mass of the piston 23, the damping of the shock absorber can decrease to zero at high frequencies of the movement of the unsprung mass. The movements of low frequency and great amplitude can be damped in the optimum manner.
In the embodiment according to Fig. 2, corresponding parts are given the same reference numbers. This embodiment differs from that of Fig. 1 in that the mass spring system is replaced by an electromagnetic system. Moreover, the exciting element 19 is also a damper valve body. The said electromagnetic system comprises a permanent magnet 31, which is fixed to the cylinder 18, and a suspended electrical coil 32 with horizontal choke plate 33. The attracting action of the permanent magnet on the elec¬ trically excited coil causes the choke plate 33 to be pressed against a seat surrounding an outflow port 34 in the bottom of the cylinder 18.
A spring 35 which presses the piston 18 against a seat at the bottom side of the disc 7 is active between the bottom of the cylinder 18 and the exciting piston 19.
The coil 31 is electrically connected to earth at one side, and at the other is connected by means of a wire 37 to a connecting element 36 which can be connected to an electronic control system. The exciting of the coil 31 will result in a reduction or enlarge¬ ment of the gap between the choke plate 33 and the duct 34. When the gap increases a release in pressure occurs below the exciting piston 19, with the result that the piston is not pressed as hard against the damper valve seat, so that there is less damping. A reduction in the width of the gap results in greater damping.
The said electronic control system is connected to sensors which pass on information to the system on any change in the steer¬ ing angle per second, the speed of travel, the horizontal and vertical, lateral and transversal speed, the height of travel etc. This system excites the coil 34, so that a lower or higher damping level is selected. The switching speed is extremely high. The damper valve reacts to slight movements in the regulating coil. As in Fig. 1 , the damping can be switched off fully or partially if there are disturbing high frequencies in the movement of the un¬ sprung part of the wheel guide.
A disadvantage of the invention according to Fig. 2 can be that leakage between the exciting piston 19 and the cylinder 18 is not constant. Seals cannot be used, due to the additional friction.
The embodiment according to Figs. 3 and 4 does not have these disadvantages. In this embodiment also, corresponding parts are given the same reference numbers. The exciting element 19 is free from the walls of the cylinder 8, 18 and is suspended in resilient plates 49. The valve body 17 of the damper valve also consists of resilient plates. There is no risk of leaking; oil can pass through the exciting element only via duct 21. The regulating process can be accurate; the sensitivity is great. Provision is made below the throttle plate 23 for another leaf spring 41 which holds the throttle plate in the de-energized position.
In the embodiment according to Figs. 2, 3 and 4 the space below the bottom of the cylinder 18 is connected to the tank 3.
It is of essential importance for the invention that the damping takes place on both the outgoing and the ingoing stroke by means of the same damper valve, whose damping action is regulated mechanically or electromagnetically in such a way that at high frequency of the movement of the unsprung part of the wheel guide it is reduced to a minimum, while at low frequency the normal damping action is achieved. The embodiments described lead to very rapid adaptation of the damping action to the said frequency. The piston 4 in the working cylinder 1 is simple in design and has only one upstream valve which lies round the central pipe in such a way that it gives a dynamic seal. Concentrating the damping in a single regulating element is a great practical advantage. Of course, various additions and modifications are possible within the scope of the invention. For example, the duct 34 can contain a cylin¬ drical shaft with flat side or a tapering shaft which rests on the choke plate 33 and determines the dimensions of the passage accu¬ rately when the choke plate is not resting on its seat.

Claims

1. Twin-pipe shock absorber, comprising a working cylinder (1 ) , a piston (4) which is movable in said cylinder and has a passage and upstream valve (13, 14, 15), an external pipe (2) fitted round the working cylinder, an oil tank (3) between working cylinder and external pipe, a disc (7) shutting off the working cylinder and having a passage (16) and an upstream valve (17) positioned near said passage, and a damper valve, characterized in that a central pipe (10) extends through the piston (4) and with its bottom end projects through said disc (7), said damper valve is disposed at the bottom end of said central pipe (10), and regu¬ lation means are present to regulate the damping exerted by the damper valve depending at least on the frequency at which the working cylinder vibrates.
2. Shock, absorber according to Claim 1, characterized in that the valve body (20) of the damper valve is disposed on or forms part of an exciting element (19) which is displaceable up and down and has a narrow oil passage (21), and said regulating means can regulate the oil pressure below said exciting element.
3. Shock absorber according to Claim 2, characterized in that provision is made below the exciting element (19) for a mass inertia piston (23) between two springs (24, 25) or spring systems, in which piston there is a passage (28) which is provided with an upstream valve (29) and connects the space above and below the piston, there being above the piston an oil passage (27) with valves (26) which can be opened by raised oil pressure above the piston, in order to reduce the pressure below the exciting element.
4. Shock absorber according to Claim 2, characterized in that provision is made below the exciting element (19) for a throttle plate (33) fixed to one or more coils (32) which are placed in the field of at least one permanent magnet (34), it being possible to move the throttle plate (33) up and down through more or less exciting of the coils, and provision being made between the throttle plate (33) and the exciting element (19) for an oil cham¬ ber having an oil throughflow spout (34) which can be shut off to a greater or lesser extent by the throttle plate (33).
5. Shock absorber according to one of Claims 2 to 4, charac¬ terized in that the exciting element (19) is a piston which is displaceable in a cylinder (18).
6. Shock absorber according to one of Claims 2 to 4, charac- terized in that the exciting element (19) is suspended in resilient membranes (40) .
7. Shock absorber according to one of Claims 4 to 6, charac¬ terized in that a spring (41) contacts the throttle plate (33).
8. Vehicle provided with at least one shock absorber accord- ing to one of Claims 4 to 7, characterized in that the coils (32) are electrically connected to a regulation system which is in turn connected to sensors for measuring different movements of the vehicle, and which can give signals to the coils
PCT/NL1989/000016 1988-04-06 1989-04-03 Twin-pipe shock absorber WO1989009891A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US08/113,888 US5423402A (en) 1988-04-06 1989-04-03 Twin-pipe shock absorber
DE8989904258T DE68900319D1 (en) 1988-04-06 1989-04-03 DOUBLE PIPE SHOCK ABSORBER.
AT89904258T ATE68247T1 (en) 1988-04-06 1989-04-03 TWIN TUBE SHOCK ABSORBER.
US08/396,312 US5467852A (en) 1988-04-06 1995-02-28 Twin-pipe shock absorber

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL8800882 1988-04-06
NL8800882A NL8800882A (en) 1988-04-06 1988-04-06 TWO-PIPE SHOCK ABSORBER.

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WO1989009891A1 true WO1989009891A1 (en) 1989-10-19

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PCT/NL1989/000016 WO1989009891A1 (en) 1988-04-06 1989-04-03 Twin-pipe shock absorber

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EP (1) EP0408631B1 (en)
JP (1) JP2815207B2 (en)
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WO1992012359A1 (en) * 1990-12-27 1992-07-23 Koni B.V. Twin-pipe shock absorber
DE4108026A1 (en) * 1991-03-13 1992-09-17 Teves Gmbh Alfred TWO TUBE SHOCK ABSORBER
WO1992016772A2 (en) * 1991-03-13 1992-10-01 Alfred Teves Gmbh Twin-tube shock absorber
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FR2679972A1 (en) * 1991-07-31 1993-02-05 Boge Ag ADJUSTABLE SHOCK ABSORBER.
WO1993005315A1 (en) * 1991-09-06 1993-03-18 Alfred Teves Gmbh Controllable valve arrangement for adjustable double-tube dashpots
DE4132262A1 (en) * 1991-09-27 1993-04-01 Teves Gmbh Alfred HYDRAULIC VIBRATION DAMPER FOR MOTOR VEHICLES
DE4137403A1 (en) * 1991-11-14 1993-05-19 Teves Gmbh Alfred Twin-tube car shock absorber with variable damping
WO1993009966A2 (en) * 1991-11-18 1993-05-27 Itt Automotive Europe Gmbh Hydraulic adjustable vibration damper
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WO1996008950A2 (en) * 1994-12-19 1996-03-28 Koni B.V. Continuously variable twin-tube shock damper
EP0740086A1 (en) * 1995-04-27 1996-10-30 Automobiles Peugeot Arrangement for damping by fluid lamination and motor vehicle suspension system equiped with such a damping arrangement
NL1002426C2 (en) * 1996-02-22 1997-08-25 Koni Bv Continuously adjustable one-pipe shock absorber with bi-directional control valve.
WO2001011254A1 (en) * 1999-08-10 2001-02-15 Ld Design Electronics Ab Arrangement for a piston- and cylinder device
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Cited By (44)

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Publication number Priority date Publication date Assignee Title
EP0463350A2 (en) * 1990-06-19 1992-01-02 Robert Bosch Gmbh Suspension strut with a working cylinder
EP0463350A3 (en) * 1990-06-19 1992-07-29 Robert Bosch Gmbh Suspension strut with a working cylinder
WO1992012359A1 (en) * 1990-12-27 1992-07-23 Koni B.V. Twin-pipe shock absorber
US5372223A (en) * 1990-12-27 1994-12-13 Koni B.V. Twin-pipe shock absorber
DE4108026A1 (en) * 1991-03-13 1992-09-17 Teves Gmbh Alfred TWO TUBE SHOCK ABSORBER
WO1992016772A2 (en) * 1991-03-13 1992-10-01 Alfred Teves Gmbh Twin-tube shock absorber
WO1992016771A1 (en) * 1991-03-13 1992-10-01 Alfred Teves Gmbh Twin-tube shock absorber
US5400877A (en) * 1991-03-13 1995-03-28 Alfred Teves Gmbh Two-tube shock absorber
WO1992016772A3 (en) * 1991-03-13 1993-04-29 Teves Gmbh Alfred Twin-tube shock absorber
US5464079A (en) * 1991-03-13 1995-11-07 Alfred Teves Gmbh Two-tube shock absorber
FR2677095A1 (en) * 1991-06-01 1992-12-04 Bosch Gmbh Robert PREFERRED FLUID SHOCK ABSORBER COMPRISING A BLADE OF VALVES HAVING A DIAMOND INTERIOR CONTOUR.
FR2679972A1 (en) * 1991-07-31 1993-02-05 Boge Ag ADJUSTABLE SHOCK ABSORBER.
WO1993005315A1 (en) * 1991-09-06 1993-03-18 Alfred Teves Gmbh Controllable valve arrangement for adjustable double-tube dashpots
US5611413A (en) * 1991-09-06 1997-03-18 Itt Automotive Europe Gmbh Controllable valve arrangement for controllable two-tube vibration absorbers
DE4132262A1 (en) * 1991-09-27 1993-04-01 Teves Gmbh Alfred HYDRAULIC VIBRATION DAMPER FOR MOTOR VEHICLES
DE4137403A1 (en) * 1991-11-14 1993-05-19 Teves Gmbh Alfred Twin-tube car shock absorber with variable damping
WO1993009966A2 (en) * 1991-11-18 1993-05-27 Itt Automotive Europe Gmbh Hydraulic adjustable vibration damper
WO1993009966A3 (en) * 1991-11-18 1993-11-11 Teves Gmbh Alfred Hydraulic adjustable vibration damper
WO1993022582A1 (en) * 1992-04-27 1993-11-11 Itt Automotive Europe Gmbh Pilot operated valve for running gear regulating systems
FR2723159A1 (en) * 1994-07-26 1996-02-02 Fichtel & Sachs Ag ADJUSTABLE HYDRAULIC SHOCK ABSORBER
WO1996008950A2 (en) * 1994-12-19 1996-03-28 Koni B.V. Continuously variable twin-tube shock damper
WO1996008950A3 (en) * 1994-12-19 1996-05-02 Koni Bv Continuously variable twin-tube shock damper
NL9402150A (en) * 1994-12-19 1996-08-01 Koni Bv Continuously variable two-pipe shock absorber.
US5890568A (en) * 1994-12-19 1999-04-06 Koni B.V. Continuously variable twin-tube shock damper
EP0740086A1 (en) * 1995-04-27 1996-10-30 Automobiles Peugeot Arrangement for damping by fluid lamination and motor vehicle suspension system equiped with such a damping arrangement
US5842688A (en) * 1995-04-27 1998-12-01 Automobiles Peugeot-Automobiles Citroen Arrangement for damping through wire-drawing of a fluid and suspension system in particular of an automotive vehicle fitted with such a damping arrangement
FR2733564A1 (en) * 1995-04-27 1996-10-31 Peugeot DAMPING ARRANGEMENT BY ROLLING A FLUID AND A SUSPENSION SYSTEM, IN PARTICULAR A MOTOR VEHICLE, EQUIPPED WITH SUCH A DAMPING ARRANGEMENT
US6264015B1 (en) 1996-02-22 2001-07-24 Koni B. V. Continuously variable single-tube shock absorber with bidirectional control valve
WO1997031197A1 (en) * 1996-02-22 1997-08-28 Koni B.V. Continuously variable single-tube shock absorber with bidirectional control valve
NL1002426C2 (en) * 1996-02-22 1997-08-25 Koni Bv Continuously adjustable one-pipe shock absorber with bi-directional control valve.
GB2335476B (en) * 1998-03-19 2002-01-09 Tenneco Automotive Inc Acceleration sensitive damping for automotive dampers
WO2001011254A1 (en) * 1999-08-10 2001-02-15 Ld Design Electronics Ab Arrangement for a piston- and cylinder device
FR2800822A1 (en) * 1999-11-05 2001-05-11 Peugeot Citroen Automobiles Sa ARRANGEMENT FOR DAMPING THE MASS MOVEMENTS IN RELATION TO A SUPPORT
EP1098109A1 (en) * 1999-11-05 2001-05-09 Peugeot Citroen Automobiles SA Damping device for the movement of a mass in respect to a support
FR2815101A1 (en) * 2000-10-10 2002-04-12 Peugeot Citroen Automobiles Sa Damper for automobile wheels and axle comprises cylindrical casing filled with hydraulic fluid and containing piston delimiting two chambers which communicate with fluid throttling module
EP1197676A1 (en) * 2000-10-10 2002-04-17 Peugeot Citroen Automobiles SA Improved damping device for the movement of a mass in respect to a support
US10316924B2 (en) 2001-08-30 2019-06-11 Fox Factory, Inc. Front bicycle suspension assembly with inertia valve
US11346422B2 (en) 2001-08-30 2022-05-31 Fox Factory, Inc. Front bicycle suspension assembly with inertia valve
US9261163B2 (en) 2006-04-02 2016-02-16 Fox Factory, Inc. Suspension damper having inertia valve and user adjustable pressure-relief
US9746049B2 (en) 2006-04-02 2017-08-29 Fox Factory, Inc. Suspension damper having inertia valve and user adjustable pressure-relief
US10359092B2 (en) 2006-04-02 2019-07-23 Fox Factory, Inc. Suspension damper having inertia valve and user adjustable pressure-relief
US11085503B2 (en) 2006-04-02 2021-08-10 Fox Factory, Inc. Suspension damper having inertia valve and user adjustable pressure-relief
DE102010040226B4 (en) * 2009-09-10 2016-02-18 Kayaba Industry Co., Ltd. Fluid-filled shock absorbers
FR3003619A1 (en) * 2013-03-25 2014-09-26 Peugeot Citroen Automobiles Sa HYDRAULIC SHOCK ABSORBER COMPRISING A FAST RELIEF DEVICE

Also Published As

Publication number Publication date
EP0408631A1 (en) 1991-01-23
NL8800882A (en) 1989-11-01
US5423402A (en) 1995-06-13
JPH03504629A (en) 1991-10-09
US5467852A (en) 1995-11-21
JP2815207B2 (en) 1998-10-27
EP0408631B1 (en) 1991-10-09

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