DE2223037A1 - Shock absorbers - Google Patents

Description

Ilanbur.q, the 3rd Hai iy? 2

xxiorifc ^: lt: 2 _{:) 0} Hai 1971, Japan, Pab.-nrao to "57108/71 3 · June 1971, Japan, Pat.-Anrao Kr ₀ 53728/71

Notifier ;

Tokico Ltd.

1-2, hakajima,

Kawasaki-shi, Kana ^ awa-ken, Japan

Shock absorbers

The invention relates to an improved .sich combined riydraulinch-nneumatische Gtoßdämpfervorrichtung, for dio un Scli'vin ^ ^ sdämpfunp and sur support of the vehicle ;; eatell: i; ewichfces in a running wheels on motor vehicles y ^ ui- used. can be _o

HiK ir; t; known, the piston rod of such a unit oil:; hollow limb to make ^ oniu-'end Ii η um for a

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To create gas or air chambers which should pneumatically absorb shocks; Part of the liquid chamber is maintained in the interior of the cylinder and works together with a damping piston slidably arranged in the cylinder, so that an effective unit is created, by forming and maintaining a high-pressure gas chamber in the piston rod, which contains a certain, predetermined volume of a gaseous medium, preferably nitrogen or air at a pressure of 10-20 atmospheres, can be completely prevented that gas leaks from the outer end of the gas chamber, as is otherwise the case with sealing means against the open atmosphere outside the unit possible would be ₀

However, practical experience has shown that, especially when the unit is used for a long time under heavy conditions of use of the vehicle, a considerable amount of air or gas mixing occurs amount of the pressurized gas or the compressed air in the form of a large number of small bubbles containing ¹ After a considerably long period of use of the · Ponder; it; it should be noted that these vesicles need to reach the upper end of the Kliissi-

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rise and there form a gas supply which penetrates through the sealing means which are provided at this point in order to seal off the liquid from the atmosphere defined compressed gas volume gradually reduced, if the closed gas or air volume is not topped up or supplemented to replace the leaked gas volume. usual box part of the known combined pneumatic and hydraulic shock absorbers _o

The main purpose of the invention is therefore to create a Teleskopöuoisdtimpfeinheit of the above type, in which automatically the leaked and accumulated gas volume from the upper end of the liquid chamber is led back into the high pressure gas chamber, which is formed and maintained in the inner part of the cavity , which is provided in the specially built and arranged piston rod for the combined mode of operation _o

According to the invention, the cylinder is a double-walled structure executed so that an annular small gap is provided between the cylinder walls. This .Rin "space forms a gas exhaust device which is located in extended substantially the length of the cylinder

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Lateral penetrations are also provided which establish a flow connection between the upper part of the liquid chambers or a certain ram which is formed further above it and the lower part of the cylinder The gas volume expelled in this way for the return line is finally passed through part of the liquid separators or chambers or through a correspondingly provided line device into the high-pressure gas chamber. , urüeingeführte the line device is in front "U""wefce with tine !; ■ Ueck ^ ci -.lagventil equipped urn stop to provide that the sur feedback provided, bar-c-CRAZY G? svolumen in reverse Hiclitun ,; wanaert ₀

Other advantages and benefits of the invention result from the claims as well as from the subsequent description and the drawing, in which exemplary embodiments of the invention are explained and shown.
Fig. 1 shows a simplified longitudinal section through a

preferred Ausfulirungsforrri the invention, Figo 2 on an enlarged scale the upper end of the

unit shown in F ± r " 1,

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Figure 3 ₀ shows a longitudinal section through an opposite Figo 1 abgewandel-th embodiment of the invention,

Fi ^ ₀ 4 one of the Fi- ;. 1 and 3 corresponding representation of a further modification,

Fig. 5 is a longitudinal section through the end part of a compared to Fig. 1 modified embodiment,

Pig 6 shows a representation corresponding to FIG of a further embodiment and

7 shows a representation corresponding to FIG. 4 of a modified form. watch us sf orm ₀

In a first embodiment of the invention, see FIG. 1, a shock absorber has a hollow cylinder 1 which contains a certain mass of hydraulic fluid, preferably an oil, in its interior arranged, whereby a concentric gap _ν "Λ is present between uiesen two parts ο Jiiin piston 3 is slidable in cylinder 1 and arranged in a sealed manner. The interior of cylinder 1 is divided into two hydraulic chambers, namely into an upper chamber A and a lower ^1L ammor F3 "

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An elongated hollow piston rod 4 is fixed with its lower end to the piston 3 by a screw connection 29. The piston 3 has a wide central bore 16 so that the inner space 4a of the bracket 4 and the lower cylinder chamber B are in flow connection with one another the upper end of the hollow piston rod 4 is complete and extends au £ the interior of the cylinder 1 to the top _o the closed upper end dEB rod 4 is connected to a rigid end 4-b of reduced diameter is formed, the end portion 4c is provided with external threads "

A bottom member 5 i designed as a circular disc in the middle with a passage 8 and also provided with a circumferential shoulder Sa, which sits with erect fit in the lower end of the cylinder Λ »A small space 6 is between the bottom surface Sc and the bottom part 2a of the shell 2 through Arrangement of a spacer ring 7 is provided, which is formed with radial grooves, not shown in detail, so that a fluid connection between the intermediate space cf> and the intermediate space 6 filled with hydraulic fluid is present a slightly smaller diameter than dumbbell 2 at this point, --o dal:> a small space, Ί as ^:? location of the annulus -κ »is present» through the middle ijohrun, ·; H uindur'cii is

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- 1 ~

lower hydraulic chamber B in fluid communication with space 60

An existing metal guide ring 9 is between the rod A and the jacket 2 arranged and has in its central bore 10 has such an inner diameter that the rod 4- sealed in the direction of its longitudinal axis is displaceable “The rod guide ring 9 is designed with a circumferential shoulder 9a, whereby a narrow gap! passage between the top of cylinder 1 and the guide ring 9 is present and a flow connection between the upper ends of the chamber A and the Gap ^ produced

The upper part of the upper chamber A and the lower part of the Lower chamber B are therefore hydraulically connected to one another via spaces 11, C & and Fl, the radial grooves in the spacer ring 7 »the room 6 and the passage 8 connected.

The stand-erifführung 9 is in one piece with an annular ν or jump 9b formed. A sealing ring 12 is between de.Ji dumbbell 2 and the piston rod; e 4- inserted and is inserted in .x held with the κing projection

Annular space 13 is between the packing 12 and .The rod guide 9 is provided and can via a fine annular gap between the rod 4 and the rod

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Guide 9 is available, are in connection with the upper liquid space A ,, A serving as a dust protection metal ring 14 is held in contact with the jJichtung pack 12 and prevents dust and dirt particles from outside could penetrate into the interior of the cylinder 1 = for this purpose the ring 14 interacts with an elastic sealing ring 14 a, which is held between the metal ring 14 and the piston rod 4. The outer circumferential surface of the metal ring 14 is kept in pressure contact with the inner wall surface of the jacket s 2., An externally threaded locking ring 15 is screwed into the internally threaded upper end of the jacket 2 to protect the assembly from the as a dust cover serving metal ring 14, the elastic ring 14a, the packing 12, the rod guide 9> the cylinder 1 and the base member 5 is to hold against the jacket sleeve 2 in their position ₀

The wide axial bore 16 in the piston 5 provides a constant flow connection between the interior 4a of the hollow piston rod 4 and the lower liquid _{chamber B in the cylinder 2 o} The interior 4a is divided into an upper high-pressure gas or air chamber D and a lower liquid chamber C.

The piston 3 is axially aligned with fluid passages 17, 17a formed and also has

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a valve spring chamber 50, with which the passages 17, 17a to be able to contact «, within the chamber a valve spring 19 is provided, which is usually a ' Valve member 18 holds in the closed position opposite the upper passage 17 «By arranging this spring-loaded The valve member goes through the fluid flow Passages 17, 17a and the chamber 50 only in the direction of from chamber A to chamber B when the valve member 18 "is below The effect of pressure opens.

Furthermore, liquids which are axially in alignment are permeable 20, 20a formed in the piston 3 in the same way

and are in communication with a valve spring chamber 51 in the piston. Inside the chamber 51, a valve spring 22 is arranged, which usually presses a valve member 21 in the closed position with respect to the lower passage 20. Due to the arrangement of this spring-loaded valve member 21, a reversed passage of fluid from chamber B to chamber A is made possible when the valve member 21 opens under the action of pressure _{or the like}

Sin cover member 23 has the shape of a hollow cylinder, the is substantially closed at the top, but has an upper axial opening and a lower open end. The hollow cylinder 23 is fixed to the piston rod 4- at the base of the reduced diameter

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End 4b arranged in which a fastening nut 25 with the interposition of a rubber damping block 24, a washer 25 and the essentially closed end of the cover 25 is tightened against the completely closed upper end shoulder of the hollow piston rod 4 ₀ The rubber block 24 clamps part of the only simplified and vehicle chassis 27 partially shown. The chassis 27 is perforated at 27a so that the end projection 4b, 4c may be passed pipes ₀ One or annular fastening member 28 may be fixed with an axle of the vehicle or attached to the axle member, as known per se, be connected ",. The link 28 is attached to the bottom part 2a of the lower shell »

The shock absorber or support strut assembly according to the invention works in the following way:

The unit is arranged between the vehicle chassis and the wheel axle in such a way that the piston 3 is substantially is held in the illustrated neutral position within cylinder 1 when the vehicle is stationary »

When the vehicle is running and the unit is subjected to an expanding force resulting from a reciprocating oscillatory motion between the chassis and the axle, the piston becomes;>: e _; '; enüber de: u Cylinder: <ufwärtsgeschegto The i-iydri'ulikflü; T, i ": koit, preferably

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ϋΐ, which is found in the annular chamber A, is thereby put under pressure and <.by the passage or the Jurc-h ^ ünp; e 11, the spaces λ and ^, the grooves im Spacer ring 7, the space 6 and the through hole 8 driven from the chamber A into the liquid chamber B « At the same time, the pressurized liquid acts through channel 1? on the valve member 18, which thereby against the action of the spring 19 is opened, so that the liquid through the channels 17, 17a and the 'valve chamber 50 flows into the lower liquid chamber B " During the restricted flow of liquid from chamber A into chamber B through the check valve unit, the number of which can be selected accordingly instead of the one unit illustrated in the drawing can, the liquid becomes a vibration dampening Subject to flow resistance., The liquid volume, that in the lower liquid chamber B according to the decreasing volume of the piston rod 4- from the inner effective volume of the cylinder 1 is supplemented, passes from the chamber C through the axial bore 16 of the piston 3 in the chamber B. Expands in a corresponding manner the volume of air or gas under high pressure that is locked in the air or gas chamber D. and the gas pressure is reduced accordingly

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On the other hand, when the device is subjected to a contracting force due to the vibration, the piston 3 in the cylinder 1 moves downward. The liquid in the camera B is therefore compressed. the number of which, as in the case of the valve unit acting in the opposite direction, can be adapted to the requirements, instead of the check valve unit 18, 19 being opened. As a result, the same vibration-damping and viscosity effect is exerted on the liquid passing through the restricted passage 20, 20a. The volume of liquid to be released from the chamber B due to the penetration of the piston rod 4- in the lower space of the cylinder 1 goes through the axial bore 16 into the chamber C ₀ is, therefore, is compressed more so that its pressure is increased accordingly _o

While the device performs the vibration damping described here, those explained below occur Difficulty on "When the unit stops the damping process Repeatedly executes, in particular over a longer period of use, the liquid in the chamber G is of the gas or air from the camera D

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The mixing means that fine bubbles of the gas or air enter the liquid in the chamber C, so that a kind of gas-liquid mixture is formed Attenuation, the fine gas or air bubbles are carried by the liquid into the annular liquid chamber A, where they collect in the uppermost part of the chamber _o Finally they escape through the fine gap that exists between the rod 4 and the guide 9 into the annular space 13β The packing 12 must therefore seal slowly not only against liquid but also against the gaseous medium. It is known that a sealing member can seal a liquid medium more effectively than a gaseous one. An effective clearing against a gaseous medium under pressure fluctuations is usually with a sealing ring or similar means Achieved only with considerable difficulty If, therefore, a significant amount of the escaped air or gas has collected in the upper end of the liquid chamber A, the vibration damping properties of the device are indeterminate and are no longer reliable »

The various passages, channels and spaces 11j <^.} (3>7> 6 ^and 8 together form a reliable device for the return of gaseous medium, the

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has accumulated occasionally by escaping at the top of the liquid chamber A, back to the gas chamber

Assume that a significant amount of the gaseous medium has accumulated at the top of chamber A and the shock absorber assembly is subjected to a pulling force apart from the vibratory motion between the shaft and the axle. The gas then exits the accumulation space through the passages or spaces 11, cfc, and β , 7, 6 and the bore 8 in the lower liquid channel he B returned ο This gas recirculation device, which is composed of the above-mentioned parts, is designed so that it has the smallest possible total passage volume hatο the leaked through the entrainment and the accumulated volume of the cushion gas medium can 13icht and effectively returned to the lower liquid chamber B by the upstroke of the damper piston 3 exploited and a certain small movement of the piston is carried out in this sense, ₀ the thus to · uckgeführte gaseous medium is out of chamber B through the Bore passage 16 and the liquid chamber G in the form of upwardly moving gas bubbles into the gas chamber D of the hollow piston rod 4 »

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If the shock absorber unit contracts under these working conditions, the part of the return device which is formed by the through-hole 8 in the piston 3 S ^e ~ is kept in flow communication with the lower, liquid-filled chamber B, the liquid can escape from the chamber B flow into the annular liquid chamber A «.

In this way, the liquid chamber A is essentially always filled with liquid and _r leakage of gas from the interior of the shock absorber to the outside is substantially completely prevented, so that a stable and reliable damping function ensures isto

The gas chamber D, which is formed in the upper part of the interior of the hollow piston rod, is filled with a certain, predetermined amount of gas or air, which has a predetermined high pressure the drawing is not particularly indicated, and should be referred to herein as W, without using a mechanical or pneumatic spring device transmits the shock absorber unit is a proportional load Chaissis ₀ When the shock absorber unit excluded solely by the action of this force W with a support spring

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is equipped, as will be explained, carries the shock absorber unit the proportional chassis weight excluding the part that is supported by the additional .Feder will ο

The pressure of the highly compressed gas and the expansive force derived from it, here designated by P and W, respectively can be calculated from the following formulas (1) and (2):

^V ° -, T _n (D

-it T

= ψ ο el ² . P (2)

In here is

Vq is the volume of gas present in the gas chamber,

measured with the cushioning extended to the maximum

Pistons,

Pp is the corresponding gas pressure, S is the deformation of the piston-cylinder-anor dnunr ·;.,

measured from the maximally extended position

to the neutral position, and d · the outer diameter of the hollow piston rod ,,

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Due to the expanding force V / becomes, depending on the individual case the weight of the vehicle chassis completely at rest: or partially supported "

In the case of a wheeled vehicle, it is extremely desirable the height of the chassis always to a: a predetermined value depending on the increase or decrease in the weight of the chassis or to hold the load, in the case of an ars vehicles weight-bearing system, the present one In applying the invention, this condition can be met by the expanding force V / in an appropriate one Way is modified.

The following is a special facility that is used to do this is suitable to modify the force V / in the preceding sense, with reference to - ^ 'ig. 2 explained

It should be assumed that the weight side of the chassis under the steady state conditions of the vehicle '- been \ uϊ ν) ,, and the gas pressure in the chamber D according iiuf P. increased isb _o Then

₂ (3)

ο d

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Through this increased pressure P _x, the increased chassis Seifcengewicht W ^ is supported ₀ In this IVeis e is the chassis height unöer stationary conditions of the vehicle does not change ,,; / hen, conversely, the Ghassis page weight under stationary conditions of the vehicle on ή ^ and the gas pressure has been reduced _{accordingly to P 2,}

In this way, the chassis height is also unöer statio changed to the general conditions of the vehicle

FiT ₁ O 2 now shows a reliable device. ur X of the pressure in the gas chamber in the above sense ₀

The pressure adjustment device according to Mr. 2 has an axial bore 4-1 which passes through the end projection of reduced diameter 4b, 4c of the hollow pipe and communicates with the gas chamber D, two separate, mechanically coupled / valve members 4-2 and 43 are with an axially extending B-ohrungskanal _o 44 formed for the gas or air, the valve member 42 is retained within the bore 41 by a screw 42a adjustable in its position "a Dichtungspackun ¹ ·: ί'ία is fitted on the outer periphery of the valve member 43 to the bore 41 by cooperation with the inner wall surface

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to seal the stem of the rod extension «A valve fs & k 45 is axially movable with a somewhat dead body in canal 44 ο that upper end of the shaft protrudes from the valve member 42, while the inner or opposite end of the Shaft from the valve member 4-5 protrudes slightly inward into the space of the cylinder 1 and at its lowest End carries a valve disk 4-6, which in turn is provided with a sealing member 46a «, a spring 4? is under bias between the valve member 43 and the Shank 45 arranged under the conditions shown

the valve stem 45 is biased to move upward, so that the valve disc 46 is held in pressure contact with the associated valve seat 43b which is at the lower end of the valve body 43 is provided to close the flow channel 44 ",

The uppermost end of the externally threaded part 4c can pass through an extension piece and a flexible hose be connected to a high pressure gas source «, The associated Parts shd built and arranged so that by screwing the extension piece onto the threaded one Rod end 4c of valve stem 45 is moved downward in FIG is so that the valve disc 46 is lifted from its associated seat 43b ",

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In this way, high pressure gas is from the supply source into the flow passage 44 and from uort fed into the chamber D.

Instead, the rod end 4c is in the free state is left and the shaft 45, for example, by hand for movement is printed down, can be a desired specific Gas quantity can be released through the channel 44 opened in this way into the open atmosphere »In any case, the Gas pressure in the chamber D can be changed in the sense of an increase or decrease, thereby reducing the chaasis set to a desired level «,

In addition to or separately from the introduction or discharge of gas, liquid can also be introduced in the same way or submitted, by applying any of these The force / deformation curve W-S, which is not shown here, can be used for pressure-modifying measures for the load-supporting System can be modified as desired.

One slightly modified from the previous one Shape is shown in Figo 3. In this example have the same or similar components have the same reference numerals as in the previous example, regardless of minor Deviations in form or function »

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In this embodiment is or «are the small The passage or the passages 11 are preferably designed as radial grooves and are separated from the one between the guide ring 9 and cylinder 1 is moved to an upper position between the same ring 9 and the seal 12 is, so that the possibility is created to occasionally leaked amount of gas that eventually in the Annular space 13 is caught, returned again «,

In addition, a mechanical support spring $ 1 is concentric placed around the lower jacket 2 and with its upper end against the upper flange provided with a flange End of the lid part 23 ·. This part is opposite to that previous example slightly modified and made of a plastic material by the spring force the flange pressed against a spring cage 32, which substantially the cup-shaped upper end portion of the Lid part 23 of the first embodiment corresponds and clamped between the upper shoulder end of the main part of the hollow piston rod 4 and the rubber stack 24 is ο the lower end of the spring 31 is on another Spring cage 33 supported on the outer surface of the shorter jacket 2 is attached in the area of its foot part ο This spring support device is one that acts upwards The spring 31 is subjected to expansion, to fully or partially support the load of the chassis «,

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Figo 4- shows an embodiment that is further modified compared to FIG Connecting grooves 11 are on the projection 9b of the rods. guide 9 formed in the same way as in Figo 3, about leaked gas that has collected in the annular chamber 13 has to transfer from there into the annulus c ^.

In this embodiment, the bottom member 5 is formed in its center with an upwardly extending projection ^> ä which has an axial bore through which a channel 8a is formed, which a flow connection

between the space 6 and the liquid chamber C inside the hollow piston rod 4 Piston and rod 3 »4- existing arrangement is in their shown in the neutral position.

A support spring 31 »which is shorter than the i- Fig. 3, The lower spring cage 33 is arranged essentially in a manner similar to that in the example according to FIG is attached to the lower jacket 2, but on a section between its ends »

In this embodiment, a pressure V / al ζ was that an upper and a lower running surface 34- and 35 and one, respectively Has a plurality of bearing balls 36, between the upper one Spring cage 32 and an elastic holder 37 arranged,

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which, for their part, are firmly attached to the vehicle chaissis (not shown) sits. The storage unit is thereby in its position around the Bar attachment with reduced diameter 4-b, 4c held, that the nut 26 is tightened on the externally threaded rod end 4c and over a spring washer 25 the bearing holds · This storage device is used to hold a noticeable relative rotation between the piston-cylinder Unit and the vehicle chassis,

A conventional steering knuckle of a front wheel is only partially shown and at the bottom end of the lower shell 2 welded

The mode of operation of the embodiment shown in FIGS. Approximation forms is the same as that of the example according to Figo 1 and results when taking into account the accordingly changed Parts without further ado from the above explanations ο

It is also possible to combine appropriate features explained in the individual examples. This option also applies to the examples discussed below.

In FIG. 5, only the is of a further embodiment from the example of Figo 1 different part shown.

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In this example, the bottom member 5 is provided with an upwardly projecting extension 5d 'which is axially in alignment with the bore 8 »In the projection 5d a valve chamber 111 is formed which receives a check valve 109 and a valve spring 110, whereby the channel 8 is usually closed _o A centered opening spring cage 112 is screwed onto the upper end of the hollow projection ^ d *

Also in this embodiment, the leaked and accumulated gas from the upper part of the liquid chamber A through the communicating path 11, ^ C, ft, and 7 derived in the bottom space 6 _β From there, the gas is further dutch the central hole 8 in the valve chamber 111 pressed after the check valve 109 has been opened. The gas then passes through the central opening of the spring cage 112 and through the liquid chambers B and G into the gas chamber D. The check valve 109 serves to prevent the leaked gas from being returned from the gas spaces ^ and / 3 through the passages 11 in the upper part of the chamber A when the expansion stroke of the piston and rod assembly 3, 4- is relatively short,

FIG. 6 shows a further modified version compared to FIG Execution form In this example, the non-return

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valve unit, as executed in the example according to Figo 5, is arranged at the end of the long tubular extension 5a , which is formed in the axis of the bottom part 5 in the same V / eise as in Figo-4- «,

The expelled leakage gas is returned through this check valve into the liquid chamber C and from there into the gas chamber D _o

In the embodiment according to Figo 7, the axial tube extension 5d "extends into the gas chamber D, wan the Piston 3 in the neutral position shown in FIG is ο a check valve, according to Figo 5> is placed on top of the long protrusion 5 * 1 ", so that off the annular space 13 expelled leakage gas directly into the Gas chamber D is released »

- PATENT CLAIMS -

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Claims (1)

PATENT CLAIMS ο Shock absorber unit for motor vehicles running on wheels with a cylinder arranged on the wheel part of the vehicle, one end of which is completely closed and the other end of which is sealed and in which a piston is slidably disposed that the Divided interior into two separate liquid chambers and a hollow one at the lower end The piston rod is attached, the interior of which is divided into an upper gas or air chamber and a lower liquid chamber. is divided keitskammer, which is in constant flow connection with the lower of the liquid chambers of the cylinder, characterized in that the Cylinder (1, 2) is double-walled and has an elongated ring-shaped between its walls Gas channel (dO, which via Ge3führungweg (11) is connected to the upper end area of the upper liquid chamber (A) for the discharge of leakage gas quantities is and on the gas ducts (/ 3> 6, 8) for forwarding the during an expansion stroke of the piston (3) Gas expelled from the upper part of the upper chamber is connected to the gas chamber (D) are ο Device according to Claim 1, characterized in that the double-walled cylinder consists of an actual 209850/0721 -27 - ~ 27 - Cylinder (1) and a lower jacket (2), which are firmly united with one another, is composed _o 5 «device according to claim 2, characterized in that that for the collection of the leaked gas over the uppermost end of the cylinder an annular space (13) and .A seal (12) closing off the area is provided are", M device according to claim 1, characterized in that the gas ducts have one or more laterally standing channels (11) between the area (13) and the intermediate space channel (<fO » Device according to Claim 1, characterized in that the gas guide paths have one or more radial have running channels at the bottom end of the interspace channel (<£) 6. Device according to one of claims 1-5 »characterized in that a check valve (109, 110) is provided between the intermediate space channel (<£ *) and the gas chamber (D) and only opens in the direction of the gas chamber» 209850/0721