DE2119531A1 - Hydraulic adjustable damper - Google Patents

Description

Patent attorney

. WöEtsr Jackisch 9 1 1 Q R * 5

t N, Mcnzelstraßo 40 ^ '· ^ P «5 I.

g i

7 Stuttgart N, Mcnzelstrasse 40

April 21, 1971

Societe Anonyme dite;

Societe Anonyme Automobiles

Citroen

117-167, Quai Andre-Citroen ".

75 - PARIS 15eme / France A 32 299 -

Hydraulic adjustable damper

The invention relates to a hydraulic adjustable damper with a cylinder in which a piston slides is arranged, with a first damping element, which during a complete movement of the piston is traversed by the damping fluid and with a line equipped with a control valve, the end parts of which open into two specific sections of the cylinder.

In the field of automobile manufacture and development, there are adjustable dampers or shock absorber assemblies already known. It is also known to have a variable one in series or in parallel with a first damping element To arrange passage or a nozzle.

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In addition, however, experience teaches that, under fixed specific application conditions, the best properties, that can be given to a damper to establish the connection between the flow rate and the pressure to define represents a linear characteristic; one therefore also chooses such a linear characteristic, for the first damping element in an adjustable damper.

w It is found, however, that the resulting from the addition of a nozzle effect property is not satisfactory. In fact, this latter nozzle introduces a flow rate / pressure ratio characteristic which is of the parabolic type; this is disadvantageous in terms of obtaining an overall correct damping property and ultimately also eliminates the advantage gained by choosing a first damping element with a linear characteristic.

The invention has set itself the task of a hydraulic To create a damper which avoids the disadvantages of the known damping arrangements and an adjustable one Creates damper with always linear characteristics.

To solve this problem, the invention is based on a hydraulic adjustable damper with a cylinder, in to which a piston is slidingly attached, with a first Damping element, which during a complete movement

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the piston is traversed by the damping fluid and with a line equipped with a control valve, whose end parts open into two specific sections of the cylinder and consists in that a second of the control valve differing attenuation element provided which is arranged in the closed loop formed by the conduit and the cylinder area, which is located between the junctions of the line.

According to a first embodiment of the invention, the first damping element is form-fitting with the cylinder self-formed, while the second attenuation element is also positively connected to the cylinder and arranged on it, but with respect to the piston is arranged either above the first damping element or between the first damping element and the piston.

In a further exemplary embodiment of the invention, the first damping element is designed in a form-fitting manner with the piston, while the second damping element is arranged in a form-fitting manner in the line.

Finally, it is also possible, according to a third exemplary embodiment, to connect both damping elements positively to the piston itself. Regardless of the

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management example one finally chooses, results as significant advantage that both the first and the second damping element both have a perceptibly linear characteristic exhibit.

In addition, the adjustable Damper is advantageously an integral part of the vehicle suspension, with "the control of the setting the damping effect can either be done manually can, or by a control arrangement as a function on the effect of at least one of the vehicle organs. For example, it is possible to adjust the control valve of the damper by means of known transfer arrangements extremely accurate with the governing bodies of the To connect the vehicle. In this way there is the particular advantage that a considerable increase in comfort for the moving vehicle is achieved when cornering sharply.

Further advantages and configurations of the invention can be found in the subclaims and the following description in which, based on the figures, the structure and mode of operation of exemplary embodiments of the invention in detail are explained in more detail. It shows:

Fig. 1, partially in section, an element of an oil-pneumatic Vehicle suspension with an adjustable

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Damper according to the invention is used, the FIGS. 2 to 5 show a schematic representation of cross-sections through various other exemplary embodiments of a adjustable hydraulic damper according to the invention, the

Fig. 6 shows a schematic representation of the control of the damper setting as a function of the wheel lock of the vehicle while the

7 shows a schematic representation of a manually operated one Shows damper setting.

In Fig. 1, the ball 1 of a hydro-pneumatic, preferably oil-pneumatic vehicle suspension is shown. This ball is in operative connection with a cylinder 2 in which a piston 3 is slidably arranged so that the vehicle suspension or the suspension of the vehicle in which the arrangement is mounted is ensured. In addition, the individual arrangements known in the device shown will no longer be discussed in more detail will.

In the following, however, the type of assembly of two is important Damping elements 4 and 5 in the cylinder 2, which with this are positively connected. The cylinder 2 is provided with an upper element 2a, which is screwed in is connected to an intermediate element 2b.

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First of all, the damping element 5 is in the transverse direction in a bore provided in the intermediate element 2b arranged, while the damping element 4 in the transverse direction is inserted into a bore in the upper element "2a; due to the fact that the upper element 2a is connected to the The lower element 2b is screwed, the two damping elements are also form-fitting with the cylinder 2 tied together. Finally, a line 6 is also provided in the lower element 2b, which is on one side and the other Side of the damping element 5 opens into the cylinder 2, but below the damping element 4 with regard to the piston 3. In the line 6 is an adjusting valve 7 inserted, which is controlled by the tit described below in more detail with regard to FIGS. 6 and 7 can be. It should be noted that it is beneficial is to choose the dimensions of the line 6 so large that they are in view of a hydraulic flow restriction does not matter.

In Fig. 2 is a further embodiment of the in Fig. 1 described damper shown in schematic form. You can find the different ones mentioned earlier here Elements again. However, it should be noted that the damping element 5, which in turn between the closed loops is that of the line 6 and the part of the cylinder 2 between the junctions 6a and 6b, via which the line 6 opens into the cylinder 2, ge -

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forms is above the damping element 4 in terms of is arranged on the piston 3. In this case, too, the damping elements 4 and 5 are both form-fitting, with the Cylinder 2 connected.

In the embodiment of FIG. 3, the damping element 5 is arranged in the line 6 itself, with which it is positively connected; this arrangement can be made before
or downstream of the regulating or adjusting valve 7.
In addition, the damping element 4 is positively connected to the piston 3 or forms a part of the same, which is located in the cylinder 2 between the
two junctions 6a and 6b of the line 6 can move. Without wanting to go into this embodiment in more detail, however, it should be pointed out that in
In this embodiment, the two damping elements 4 and 5 can obviously no longer be distinguished by the fact that one of the two is included in "the aforementioned closed loop, since this applies to both of them in this case.

In the exemplary embodiment shown in FIGS. 4 and 5, the two damping elements 4 and 5 are finally connected to or form with the piston 3 in a form-fitting manner
Parts of the same. The damping element 5
move in the cylinder 2 between the two junctions 6a and 6b of the line 6, while the damping element 4

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either above the junction 6a, as in Fig. 4, ″ or arranged below the junction 6b, as shown in FIG is.

The preferred exemplary embodiments of the invention that have just been mentioned by way of example can also be used in many other ways Form, which will not be discussed further here, but which are obviously within F: of the scope according to the invention are to be classified. It should be in only two further variants are discussed below; for example, the exemplary embodiment 2 can be modified in such a way that, although the damping elements 4 and 5 are arranged relative to one another retained, the damping element 4, however, with a form fit

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the piston 3 can be connected. Besides, it is for example It is possible that the damper shown in FIG. 4 can be modified to the extent that the damping element 4 is not positively connected to the piston 3, but with cylinder 2,

It should also be noted that the pressure / flow rate properties the attenuation elements 4 and 5 very precisely are selected linearly. In addition, as before already briefly mentioned, the control valve 7 and the line 6 can be designed so that when the control valve is fully open 7 it is avoided that both combined with each other exert any limiting influence »Should this

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not be the case, then you run the risk of attenuators or to introduce terms that no longer have any linear properties, which one has just sought to avoid.

In Fig. 6 is a control arrangement for setting the valve 7 as a function of the speed of the steering angle or the angle of the front wheels 8 of the vehicle * This steering angle is determined, as is well known, by a steering wheel 9 * with which a drive pinion Io for performing a rotation in a form-fitting manner is connected and is operatively connected to a rack 11. The rack is in turn known about a Linkage 12 is connected to the front wheels 8, only one of which is shown in FIG. 6.

The control arrangement for setting the valve 7 is interposed in this steering linkage. The control arrangement has a piston 13 which can move in a bore 14 in the component 15 of the control arrangement. The component 15 is firmly connected to the chassis of the vehicle. The bore Ik communicates with a second bore 16 via two lines 17 and 18 which are provided at their end parts. A piston 19 is slidably arranged in the bore 16 and is held in a central position by two springs 2oa and 2ob in the absence of a control fluid in the component 15. With the piston 19 is a control lever

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of the valve 7 connected via a known connection arrangement 22, which consists of a corresponding mounted, mechanical linkage, from one hydraulic Arrangement for the transmission of movements / or, as in that Embodiment shown in Fig. 6, from a cable may exist, which slides within a casing 23. Finally, it should be noted that one of the pistons 13 or 19, in the exemplary embodiment the piston 19, with a calibrated opening 19a running transversely through it is provided.

Of course, the setting of the valve 7 can also about other work or movement parameters of the vehicle instead of the turning speed of the front wheels 8. It can also, as shown in Fig. 7, can also be carried out by hand, specifically via a control button 24, which is connected to the aforementioned cable 22 connected is. If you make a predefined setting, the control handle is, for example, in the position indicated at 24a.

The advantages of the damper according to the invention or the damper arrangements can follow the description of the mode of action can be taken even more precisely. The common point of the various dampers described above was obvious to see that they have an attenuation insjfcejLl-. possibility through partial or complete coverage of a

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Had a line connected to part of the cylinder closed loop within which (at least)

one of the two damping elements, namely the damping element 5 is arranged.

This is of essential importance because it results in the setting of a damping range and not a simple discharge of fluid into a free line. Moreover, it hardly matters whether the two damping elements h and 5 'are connected in series one behind the other, as shown in FIG. 1, or in parallel in FIG. 3. It should be noted that the total attenuation expressions obtained are not identical in the two cases, but the attenuation setting is ensured in an analogous manner. This damping setting is all the more satisfactory in that, since the individual properties of the damping elements 4 and 5 have been selected of the linear type, the damping setting by the valve 7 also allows an overall perceptible linear damping to be obtained; it is recognized that this is the best type of cushioning to obtain satisfactory comfort in the vehicle suspension.

The mode of operation of the exemplary embodiment in FIG. 7 is quite simple, since actuation of the control handle 24 and pulling out to the position 24a on the cable 22, which leads to a pivoting of the lever 21. This

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then takes the valve 7 with. On its part, "from the

open position of the line 6 in a partially or fully closed position of the line. You get to " this way of a damping setting that allows the passage of fluid only through the damping element 4 of Fig. 1 corresponds to a damping setting that the passage of the fluid through the damping element 4 and, at least in part, also by the damping element κ corresponds in this exemplary embodiment. As a result, the amount of damping increases accordingly in this case the desire and will of the operator who operated the control handle 24.

The embodiment of Fig. 6 also finally leads to an actuation of the cable 22 and consequently the Valve 7 · As the resultant mode of action is generally understandable, will not be used in the following This is discussed in more detail, but rather the mode of operation of the control arrangement that can be traced back to the component 15 is intended to be more precise to be discribed.

If the driver turns the steering wheel 9 of his vehicle quickly, then on the one hand he causes the front wheels 8 of his vehicle to turn quickly and calls at the same time a rapid displacement of the piston 13 emerges. This simultaneously causes a fluid shift through the

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Lines 17 and l8 from one space of the bore 14 into the a space of the bore 16 and at the same time and in addition to this from the other space of the bore 16 into the other space of the hole 14. For the first time, the Move piston 19 against the action of springs 2oa and 2ob and take the cable 22 with you, so that the total damping grows. Such an effect is interesting and important and allows the suspension to be adjusted in sharp turns or to dampen the vehicle suspension effectively, reducing the discomfort, which of important, insufficiently dampened Transverse vibrations of the vehicle is caused, reduced or made to disappear. Such transverse vibrations are carried out by vehicles that are not equipped with adjustable dampers according to the invention.

If the curve continues and as a result the driver stops the steering wheel is essentially immovable with the front wheels turned, then the piston 19 returns the action of the springs 2oa or 2ob back to its starting position in which the fluid is calibrated by the opening 19a flows. In this way you get a correspondingly weakened damping, as when driving straight ahead, whereby a satisfactory suspension comfort is guaranteed.

In fact, this is exactly the effect one is aiming for, because it is completely sufficient, especially at the beginning of a curve,

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to prevent excessive lateral movement of the passenger compartment ", in which case, however, an exaggerated hardening of the suspension or the suspension of the vehicle is also seen wants to avoid tackling the curve. Finally, see the road on which the motor vehicle is traveling in a straight line again then the driver leads by turning on the steering wheel, the front wheels back into the straight ahead position, with the same effect as the beginning of the Curve builds up, but this time with a reverse flow of the fluid in the bores 14 and 16, whereby again a temporary increase in the damping of the vehicle suspension is evoked; this growth occurs all the more, the faster the steering wheel is turned.

Finally, it is easy to see that with very special Applications, for example when driving very quickly on a strongly curved, sinusoidal one Road, it is desirable to adjust the damping setting not only to the speed of the steering angle, but also to the steering angle of the wheels 8; in this case it is sufficient to omit the calibrated opening 19a, to get the desired setting.

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Claims (8)

Claims: A? 2 299 - ot l ^ Hydraulic adjustable damper with one cylinder, in which a piston is slidably arranged, with a first damping element, which during a complete Movement of the piston traversed by the damping fluxdum and with a conduit equipped with a control valve, the end parts of which are divided into two distinct sections of the cylinder open out, characterized in that a second, different from the control valve (7) Damping element (5) is provided, which in the closed loop is arranged, which is formed by the line (7) and the cylinder portion, the is located between the junctions of the line (7). 2. Damper according to claim 1, characterized in that both the first damping element (4) and the second damping element (5) form-fit with the cylinder (2) are connected, and that the second damping element (5) is arranged in the cylinder (2) with respect to the piston (3) above the first damping element (4). 3 damper according to claim 1, characterized in that the second damping element (5) is arranged between the first damping element (4) and the piston (3). 109846/1265 4. Damper according to claim 1, characterized in that the first damping element (4) is positively connected to the piston (3) and the second damping element (5) is arranged positively in the line (6). 5. Damper according to claim 1, characterized in that first and second damping element (4,5) in a form-fitting manner are connected to the piston (3). 6. Damper according to one of claims 1 to 5 » characterized in that each of the damping elements (4,5) has a linear characteristic. 7. damper according to one or more of claims 1 to 6, characterized in that the damping arrangements are an integral part of a vehicle suspension and that the adjustment of the control valve (7) takes place due to the action of at least one of the vehicle organs (8, 9) '. 8. Damper according to claim 7 »characterized in that the Adjustment of the regulator valve (7) via known transmission arrangements is connected to the control organs of the vehicle. 109846/126 5