DE3823043A1 - Suspension for vehicles - Google Patents

Abstract

In a suspension for vehicles with a spring strut, arranged between vehicle body and axle and comprising a working cylinder with piston with piston rod sliding therein, and with upper and lower working pressure chambers relative to the piston, which chambers are connected to one another by way of a non-return valve and also to a pressure accumulator (pre-loaded spring), it is proposed that a control slide valve (11) with at least one variable passage cross-section (f1(s), f2(s), f3(s)) be hydraulically driven by a control pump (12) with hydraulic drive (13) also assigned, and to derive the hydraulic drive (13) for the control pump (12) from the excess quantity resulting from compression of the spring strut (10), with pressure medium circuit in the spring strut (10), control slide valve (11), control pump (12) and control pump drive (13) altogether sealed off from the outside. <IMAGE>

Description

State of the art

The invention is based on a suspension for vehicles according to the preamble of claim 1. Known Fede Stanchions for motor vehicles have suspension and Damping the wheel masses on separate units; it but is also already known, suspension and damping components together in one (hydraulically effective) Unite shock absorber. The variety of suspension con scepter that from simple shock absorber with spring too complicated combined spring and damping units can be divided into three main areas share, namely the mainly widespread so-called called passive suspension, for influencing of a fast-running suspension process none in external energy is then supplied to this sense or external interventions can only be done slowly and for  Damping separate shock absorbers, if necessary are also provided in an integrated form. A sol che passive suspension can be used in a wide range different spring stiffness and differ set damping properties, for example wise stiff suspension with soft damping or vice versa returns, depending on driving comfort or tailored to the respective vehicle. Such passive suspension also includes common hydropneumati cal springs, which are supplemented by level controls can.

A second category of vehicle suspension includes the so-called semi-active suspensions, which are basically are designed so that the suspension suspension in terms of their temporal ver run through quick control interventions on the damper in a suitable Way is affected. The semi-active suspension ver is looking for an active spring component, so to speak simulate that if due to the current Suspension process the supply of external energy, thus actively influencing the suspension process existing damping options would be required be controlled so that the malfunction becomes a minimum (DE-OS 35 24 862). With such a semi-active suspension can already have significant external requirements Control intervention may be required, in particular fast switching valves that match the wheel frequency are able to work and it is it is necessary to record the wheel and body movements and in the overall electronic control concept of  semi-active suspension.

A third possibility concerns the so-called active Suspension, which is effective when the particular Suspension process makes this necessary from the outside not only through appropriate control intervention Adjustment of control elements is intervened, but active energy from outside the suspension area is supplied in this way, for example by means of a pump controlled pressure increase of the hydraulic oil that Ver Changes in the force acting on the wheel are possible. However, this requires the use of some very high hydraulic performance and use elaborate controls.

In contrast, the present invention is based on assumed the basis for suspension for vehicles form that not only from the supply external hydrau energies can be completely disregarded, but with a simultaneous reduction in the amount used control effort with suspension a shock absorber with variable spring stiffness and variable damping with rule that can be configured as required strategies are created that, if at all, only very little external control intervention makes demands. The supply of hydraulic energy from the outside should only be used for purposes of a existing level control.

Advantages of the invention

The suspension according to the invention solves this problem  the characteristic features of the main claim and has the advantage that, apart from a possible Pressure feed via pump and control valve one additionally assigned level control, which from the Control units and the shock absorber formed common same hydraulic circuit completely closed to the outside sen and the possibilities of determining the va stable spring stiffness or variable damping through a kind of finely tuned own tax tion can be achieved, where appropriate for the change the spring stiffness from the outside a yes / no function for a control throttle is due to special processes.

Nevertheless, the system according to the invention a variety of possible control strategies for an Fe depending on the design of each one set components, the respective pressure ratio nisse, throttle cross sections u. the like

The drive for the cross-sectional tax to be applied stanchions of a control valve, the passage cross cuts both the spring stiffness and the Cushion damping can affect wins one over a control pump drive, which its Druckbe impact from working the strut wins, namely during its compression process, the return Suspension in the shock absorber at the same time the provision of the control slide according to time functions in the off aisle position allows with optimal coordination the suspension process as well as individual processes at Suspension process.  

The invention enables due to the elimination agile control elements, e.g. fast magnet valves, creating an inexpensive suspension systems and the use of native control strategies to master the in practical driving kick strut excitement. Since this is almost the reason can take any form conception of the present invention a variety of adjustable parameters, so that a possible order comprehensive spectrum in the area of desirable Control strategies can be covered.

A possible control strategy is given below give:

• 1. The spring stiffness can be designed that with decreasing excitation frequency if decreasing;
• 2. interpretation is possible in the same way, such that the attenuation with decreasing pathogen frequency increases;
• 3. with several successive, approximately similar excitation vibrations on the spring The effects can be according to the Points 1.) and 2.) according to a time function be trained up to pre given limit values that should not be exceeded. Exceptions to this: suspension processes, the  through special signals (activation) early are recognized as special events - on this will be discussed further below in point 6.) gene;
• 4. the course of the time function mentioned in point 3.) can be determined so that the transition takes longer at low excitation frequencies than at high excitation frequencies - the exception of point 6 applies here too);
• 5. The influence of the excitation amplitude can be less be held as that of the excitation frequency, so that after exceeding one by design predetermined threshold amplitude the further Influence according to points 1.) and 2.) is significantly weakened or is eliminated (singular processes);
• 6. in suspension processes, which, as mentioned, due of special signals (activation) very early recognizable as special suspension processes at an early stage are, the basic regulation can limited rapid intervention on the spring stiffness be made. Since this is a clearly definable, also in terms of their impact on time clearly identifiable individual transactions can this intervention between predetermined Limit values in the process as a yes / no function (Black / white control). Such processes can be, for example: venfahrt (for example by recording lateral acceleration), brakes, Accelerate, occurrence of a completely different one Road conditions or the like;  
• 7. it is possible to correspond to the damping intervention according to point 2.) for compression and rebound depending on the design of the individual used Components so different to address bring that damping when rebounding increases more than with compression;
• 8. to compensate for different loads including one in the sense of the previous one Conception of slowly responsive level control be provided by which, after the Compensation, in total with increasing load together with the prevailing spring stiffness level is lifted.

By the measure listed in the subclaims These are advantageous further training and improvements possible in the suspension specified in the main claim, including the introduction of further or modes defied control strategies. It is particularly advantageous the overall hydraulic concept on the one hand driving at the same time, so the required Control energy supplying, and on the other hand controlled Shock absorber.

drawing

An embodiment of the invention is in the  Drawing shown and is in the following Description explained in more detail. The drawing shows in the basic concept is partly schematic tion of a shock absorber with variable spring stiffness and variable damping with closed pressure with telkreislauf and a separate detail on Control slider to limit the control serves.

Description of the embodiments

The basic knowledge of the present invention is based insist that by simultaneously exploiting the hydraulic pressure supplied by a shock absorber energy and one of them in the closed hydrauli circuit derived simultaneous control for the pressure medium flow from the two working pressure rooms of the shock absorber is possible, a shock absorber with variable Spring stiffness and variable damping and under Based on a variety of possible control strategies gien to create, the damping over a steady adjustable throttle regulated and supplemented by an additional controlled rapid intervention via another control throttle in the sense of a yes / no Function the spring stiffness can be influenced.

In the drawing, the following main components in hydraulic active connection are Darge, which together realize the basic concept of a shock absorber with variable spring stiffness and variable damping and, if desired, control interventions from the outside, together: A shock absorber 10 and a control slide 11 , which controls pressure connection lines between the two working pressure spaces formed by the shock absorber and other hydraulic components of the system via at least one variable passage cross section, a control pump 12 for driving the control slide 11 and a control pump drive 13 , which can also be regarded as part of the control pump. The structure is completed by a first basic storage spring 14 and a constant by the control slide, and on request by control intervention from the outside switchable second storage spring 15 , a variety of in the following to be explained in detail hy connecting lines between the components and check valves arranged in these.

The shock absorber 10 can be of basically conventional construction and comprises a working cylinder 16 , in which chem a piston 17 with a piston rod 17 a is guided in a sealed sliding manner. Assuming for a better understanding that the working cylinder 16 at 18 (articulated) is mounted stationary on the structure, then with respect to the piston rod 17 a due to the displacement of the piston 17 in the working cylinder 16 a deflection corresponding to the current momentary suspension process ges in the direction of W e + s and a rebound in the direction of the path - s, where the piston rod remote from the eye 17 b about the axis of a vehicle (on one side) may be attached. Sensors can be provided which detect and implement the respective instantaneous spring travel that occur, the frequencies and amplitudes as well as, if necessary, also speed and acceleration values of the current spring travel and feed a control logic circuit 19 , which is only indicated schematically, which, as far as in the comprehensive basic hydraulic concept required at all, circuit components accessible to an external controller. This will be discussed further below. A corresponding path, frequency, Ge speed and other values sensing sensor is also shown only schematically at 20 .

By sealing the piston 17 and of course the piston rod 17 a in the working cylinder 16 results in an upper pressure or working space 20 a and a lower pressure or working space 20 b , the cross section of the piston with D 4 and the piston rod with D 5 is designated. The prevailing system pressure or equilibrium pressure prevailing in the overall system without movement of the piston rod 17 a is denoted by p _F and can then assume various values during operation.

At this point it is first noted that the specified in the drawing, very special pressure lines between the strut 10 , control slide 11 and its drive and the Spei cherfedern only indicate a possible, even if before ferred embodiment of the present invention, but not the invention restrict this special connection circuit. In the basic concept shown here, the control slide closes or opens flow cross-sections (continuously) which, in deliberate contradiction, on the one hand influence the spring stiffness of the system and on the other hand change the damping during compression and rebound (separately).

In the illustrated embodiment, but not limited to here, the control slide 11 has several, for example three, dependent on the stroke s _{s of} the control slide control cross sections f ₁ (s), f ₂ (s), f ₃ (s), which, like it goes without saying that they can have any cross-sectional shape according to the design.

In the exemplary embodiment shown here, the passage cross-section f ₁ (s), which varies with the stroke, serves to determine and change the spring stiffness of the system, the passage cross-section f ₂ (s) serves to damp the shock absorber during compression (i.e. in the + s direction) and the passage cross-section f ₃ (s) the setting or determination of the damping when rebounding, i.e. movement of the shock absorber in the direction of - s. In a first approximation, the passage cross sections shown in the drawing, also in their relative assignment to each other, can be taken qualitatively for the following consideration, ie, that when the control slide 11 moves downward in the bore 21 of the control slide housing (not shown) down, for example the passage cross-section or control cross-section f ₁ (s), which is too constant for the spring stiffness, is reduced, while the other two passage cross-sections f ₂ (s) and f ₃ (s) become increasingly larger. This takes into account the demands made further above in points 1.) and 2.) - an increasing excitation frequency of the spring can, of course, depending on the design of the individual components in the overall system, lead to the control slide 11 in its time-dependent movement supply sequence can no longer run fully or only a little - from the starting position shown in the drawing - so that the passage cross section f ₁ (s) is increasingly throttled and the passage cross sections f ₂ (s) and f ₃ (s) increasingly in one opening remain in position.

As can be seen in the drawing, namely connects the passage cross section f ₁ (s), which is responsible for the spring dersteifigkeit, the second or additional storage spring 15 via a hydraulic connecting line 22 with the connection point 23 and via the line 23 'and one more Control throttle 24 to be explained with a variable throttle cross section f ( β ) with the first storage spring 14 , so that in the parallel connection of these two storage springs 14 and 15 with an open passage cross section f ₁ (s), a softer Federungsver is evidently obtained than in the case of the Passage cross section f ₁ (s) of additional storage spring 15 that is increasingly switched off or shut off and its influence on the mean total pressure in the system.

The control throttle 24 just mentioned can be preferably designed so that it suddenly switches on or off the additional storage spring 15 in the sense of a black / white function between limit values, where the control throttle is due to only very small requirements in terms of function and ability 24 applied electronics and therefore he can be cost-effective. However, it is understood that a continuous adjustment of the control throttle 24 is possible and is within the framework of the invention; in any case, by loading the control throttle 24 , the advantages and demands of the strategy point 6 mentioned above can be met.

The structure of the control slide 11 is completed by a lower pressure chamber 25 , which is connected via a connecting line 26 directly to the main pressure line 27 , which is also connected directly to the upper working pressure chamber 20 a of the strut 10 . Furthermore, the lower pressure chamber 25 of the control slide 11 is connected via a bypass line 28 and a bypass throttle 29 contained in this bypass line 29 with the throttle cross section f _bypass to the upper pressure chamber 30 , the lower pressure chamber 25 being formed by enlarged bore subregions in the control slide housing. Finally, in the lower pressure chamber 25 of the control slide there is a preload spring 31 , which generates the spring force K ₃ , which moves the control slide in the direction of its starting position, that is, against its deflection s _s .

The control slide is driven by the pressure p _R prevailing in its upper pressure chamber 30 , which is excessive compared to the system pressure p _{F and is} generated by the control pump 12 . The control pump 12 includes a hydrau lisch driven piston 32 which gleitverschieb Lich in an only schematically indicated bore 33 of the variable displacement pump 12 is mounted and a Druckar beitsraum 34 limited, the check valve via a first feedback in the form of a suction valve 35 with the main pressure line 27 and a second check valve in the form of a delivery valve 36 is connected to the upper pressure chamber 30 of the control slide 11 .

The piston 32 of the control pump 12 is also suitably spring-preloaded in a larger pressure chamber 37 , which belongs to the control pump drive 13 , the preload spring being designated 38 and generating a spring force K ₂ . The piston 12 protrudes into this pressure chamber 37 from its constricted bore 33 assuming its cylinder guide and carries a spring plate 29 on which the biasing spring 38 is supported on one side, while it bears on the other side of the bore base of the pressure chamber 37 .

The pressure p _A prevails in the pressure chamber 37 , which is generated by the drive piston 39 of the control pump drive 13 . By the stepped bores in the region of the control pump drive and the variable-capacity pump with the diameters D 1 of the drive piston and the diameter D 2 for the control pump piston there is a corresponding pressure ratio, so that by layout default of the pressure prevailing in the main pressure line 27 pressure _F p to the a side of the drive piston 39 a accordingly excessive, p the regulating slide 11 antrei bender control pump pressure _R can be produced, which closes the check valve 35 and the control slide about 11 continuously in certain positions along the regulating slide travel s _s shifts, in response to the amplitude of the compression travel of the Suspension strut 10 or the excitation emanating from the suspension strut in practical driving operation, which can basically take any shape, such an excitation spectrum can only be processed statistically anyway.

The area of the drive piston and the control pump is completed by a further check valve 40 in the drive piston, which opens at a corresponding overpressure in the pressure chamber 37 of the control pump against the pressure p _F in the main pressure line 27 and in this way always a pressure equilibrium by mutual hydraulic Interaction with other components that are operatively connected to the drive piston, control pump and control slide valve.

A further influencing variable, which is very important for the achievement of certain control strategies, results in the present invention in that a connecting line 41 which is adjustable in terms of its cross section to constant values or is stepped or continuously controlled from the outside is provided between the upper pressure chamber 30 of the control slide, which is acted upon by the high re gel pump pressure p _R and the pressure p _F which prevails above the drive piston 39 or acts on it. In particular, this pressure connection is made so that an opening 41 a of the connecting line 41 into the drive piston slidably receiving bore in the region of the re gel pump drive is provided at a height that communicates with an annular recess 42 of the drive piston 39 in the starting position, which is connected via internal transverse channels to the space in the interior of the piston, which at the same time serves to receive and support the check valve 40 which has just been mentioned. The path that the drive piston 39 can travel at full stroke corresponds to the dimension s _p indicated in the drawing, which means that in the area of the maximum stroke the upper ring edge of the ring recess 42 has controlled the opening 41 a of the connecting line 41 , in addition with an additional overlap s _Ü , this overlap measure being an essential design variable of the control strategy sought in each case.

From the drawing it can also be seen that the maximum male stroke s _{p of} the drive piston 39 is also limited by the fact that the lower edge of the recess 42 in the piston controls the widened shape of the pressure chamber 37 so that it compensates for a pressure both pressures p _A and p _F comes and a corresponding stroke limitation of the drive piston 39 .

In the connecting line 41 from the upper pressure chamber 30 of the control slide 11 to the pressure p _F in the drive piston ben 39 there is also a further, also very important design variable for the respective control strategy, namely a second control throttle 43 , which is preferably also designed to be continuously adjustable by external influence can. The second control throttle has a continuously variable control cross-section f ( α ). In individual cases, the cross section f ( α ) can also be constant.

In this connection, the supply and discharge lines to the passage cross sections controlled by the respective control edges of the control slide 11 are still to be completed. Connected from top to bottom in the drawing, the first passage cross section f ₁ (s) connects the additional storage spring 15 to the general pressure level via the first control throttle 24 , so that the two storage springs 14 and 15 are connected in parallel and one of the first storage spring 14 Connection 44 to the main pressure line 27 via an opening in this direction Rückschlagven valve 45 , so the second passage cross section f ₂ (s) of the control slide 11 connects the same connection point 23 , which leads via line 23 'to the first control throttle 24 , via a Connection line 46 to the pressure chamber 37 of the control pump 12 , wherein, as already mentioned, the pressure chamber 37 also serves the hydraulic connection between the drive piston 39 and the piston 32 of the control pump 12 .

The third flow section f ₃ (s) of the control slide bers 11 of a bypass line 47 connects in the form of the lower working pressure chamber 20 b to the upper working pressure space 20 a of the strut 10, which parallel a check valve is this 48 which is at a higher pressure in the upper working space 20 a (spring deflection), depending on the design of its opening characteristics.

The structure described so far is finally completed by the possibility of supplying pressure in the previously described, overall closed hydraulic system from the outside via a feed line 49 for realizing a level control, the pressure being supplied via a pump and a control valve, which together with 50 can be designated. The level regulation forms a slow pressure adjustment and represents, in addition to the control throttles 24 and 43 with f ( β ) and f ( α ), a third external intervention possibility, so that the strategy point 8) mentioned earlier can be taken into account accordingly.

In such an overall control system with specific hydraulic strategies that can be implemented by selecting or emphasizing specified parameters, desired control strategies can be implemented in addition to the external intervention options, and also speed-dependent movements, especially in the control slide area, since the control slide has a basically speed-dependent control pump moved and under spring force and in this state otherwise pressure balanced against adjustable throttles 43 with cross section f ( α ) and 29 with f (bypass) performs its return movement. As a result, a frequency dependency occurs at the control cross-sections of the control slide, which can be used to implement the desired control strategy and adjusted accordingly, including the bypass throttle 29 with the cross-section f _bypass and the coverage dimension f _Ü , which have already been mentioned above is.

It is understood that there are precise instructions like this Parameters to be dimensioned individually are in the range penetrate the dimensions; these are not required and otherwise freely definable values depending on the desired rule to be implemented strategy based on the rules shown stems with completely self-contained printing with tel cycle.

The following basic functional mechanisms can be implemented. The spring stiffness is influenced by a stepless, that is to say continuous or by sudden switching on and off of the storage spring 14 within certain limits; this can take place depending on external road influences or a desired choice of driving behavior (comfortable, sporty).

The control slide 11 works at the excitation frequency of the shock absorber 10 and controls the three cross sections provided here depending on its stroke s _s (with any cross-sectional profile depending on the design), the spring stiffness above f ₁ (s) and in the opposite direction via f ₂ (s) (s) spring damping during compression and f _3, the attenuation at the corner. The return speed of the Regelschie bers, whereby the increase in the constriction of the passage cross section f ₃ (s) and thus the suspension damping is influenced (via line 47 ) depends solely on the spring force K ₃ , on the diameter D 3 (diameter of the control webs of the control slide), from the respectively set cross-section f ( α ) of the control _throttle 43 and from the cross-section f _{bypass of} the bypass 29 , which, with a corresponding time delay, ensures pressure equalization between the upper and lower pressure chambers 30 , 25 on the control slide 11 . These are essential design parameters of the controller thus formed, which also includes the shock absorber 10 integrally, the advance of the control slide 11 being effected by the pressure medium delivery of the control pump 12 , which generates a control pump pressure p _R that is higher than the rest of the system pressure. The control pump 12 itself is in turn hydraulically driven by the upstream "drive control pump", realized by the drive piston 39 with diameter D 1 , which performs a stroke s _A , which, as explained, is limited to the value s _p by activation is.

Therefore, other essential design features of the controller thus formed are also the diameter D 4 of the piston 17 of the shock absorber, D 5 of the piston rod 17 a of the shock absorber, D 1 as the diameter of the drive piston 39 , D 2 as the diameter of the control pump piston 32 , D 3rd as the diameter of the control webs of the control slide and the paths s _F as the respective movement amplitude of the piston 17 in the strut 10 and the path s _p as a stop dimension for the maximum stroke movement of the drive piston 39 . This stop dimension s _{p also} determines the behavior of the overall control system in accordance with point 5 above), since this results in a reduction of the influence of the excitation amplitude, that is, the original output stroke of the shock absorber.

The drive piston 39 and the piston 32 of the control pump 12 go through the action of the spring 38 generated by the biasing spring force K 2 with each suspension movement unthrottled in the opposite direction to the stroke s _A , which can be done up to the housing-fixed impact of the drive piston 39 . In a further rebound on the spring leg 10 of the wide re reflux is carried out from the additional memory spring 15 - and even when the control variable throttle 24 ge closed - undisturbed, namely about the drive piston 39 provided non-return valve 40, which forms a relief valve. The additional control of the return channel 41 of the second control throttle 43 about its annular groove 42 of the drive piston 39 affects the return speed of the control slide 11, because at maximum stroke s _p of the drive piston 39 of the return duct 41 is closed on the Dros sel 43rd Here, then, the Überdek plays kung f _Ü an essential role, for 39 of the reflux can with a closed return channel according completely hochgepumptem drive piston (of course, in the plane in the extreme downward position) only via the bypass throttle valve 29 with the cross-sectional f _Byp effected so that this slows down the Rücklaufgeschwin speed of the control slide and accordingly the time behavior of the controller overall in this control state.

At this point it should also be mentioned that the control slide 11 also has a hydraulic stroke limitation, which is shown in more detail in the individual illustration in the drawing at the bottom right; It can be seen that when a maximum determinable stroke s _{smax of} the control _slide 11 is reached, the upper edge 11 a of the web 11 b which directly delimits the upper pressure chamber 30 b releases the connection to the line 23 'on the downstream side of the second spring accumulator 15 , that is to say opens , so that there is a pressure relief of the control pump pressure p _R. In this case, the maximum stroke there is still a residual overlap s ' to the connection side with the second memory spring 15 , so that the inflow area for stroke limitation of the inlet from the second storage spring 15 is closed.

The following diameter relationships generally still apply: D 1 < D 2 and D 2 ≦ D 3 , where the pressures then assume the following values: p _A < p _F and p _R < p _F.

It is important to point out that the control system thus formed, including the spring strut 10, even with a constant throttle cross section f ( α ) = const. the throttle 43 has an impressed Regelcha characteristic, so that it may be possible to find a design for the hydraulic controller with which the whole spectrum only with f ( α ) = const. can be covered. In this case, an electrical adjustment for the throttle cross section is not necessary, although the points 1), 2), 3), 4), 5) and 7) mentioned above are also met with a control throttle 43 which is then fixed are, so that a simple electronic control le diglich for the switching function of the control throttle 24 and in addition for the level control 50 is sufficient. Even if an electrical adjustment for the throttle cross-section f ( α ) is to be provided, much lower demands have to be made of these, compared to the usual effort for direct switching solenoid valves and their required control strategy of a corresponding electronic control unit. Furthermore, the present invention eliminates the need to control extremely large flow rates extremely quickly with accordingly sophisticated control strategies. This control process takes place in the hydraulic regulator, as described, instead, which can continuously intervene during any individual vibrations.

Finally, it is possible to slowly adjust the throttle cross section f ( α ) of the throttle 43 as a function of simple signals, for example as a function of the oil temperature or of the steps selected by the driver.

All in the description, the following claims and the features shown in the drawing can both individually as well as in any combination with each other be essential to the invention.

Claims (22)

1.Suspension for vehicles, with a arranged between the body and axle, a working cylinder with in this sliding piston with piston rod encompassing strut, and with reference to the Kol ben upper and lower working pressure chambers, which are connected to one another via a check valve and also with a pressure accumulator ( Storage spring) are connected, characterized in that a regulating slide valve ( 11 ) with at least one variable passage cross section ( f ₁ (s), f ₂ (s), f ₃ (s)) is provided,
that the control slide valve ( 11 ) is hydraulically driven by a control pump ( 12 ) with an associated hydraulic drive ( 13 ),
that the hydraulic drive ( 13 ) for the control pump ( 12 ) with the resulting from the deflection of the spring leg ( 10 ) resulting in excess quantity is in total outwardly closed circuit of the pressure medium in the spring strut ( 10 ), control slide ( 11 ) , Control pump ( 12 ) and control pump drive ( 13 ) and that
the at least one variable passage cross section ( f ₁ (s), f ₂ (s), f ₃ (s)) in the control slide valve ( 11 ) connects the two working pressure chambers ( 20 a , 20 b ) of the shock absorber ( 10 ). 2. Suspension according to claim 1, characterized in that a directly with the upper, at the compression pressure-generating working pressure chamber ( 20 a ) of the spring leg ( 10 ) connected to the main pressure line ( 27 ) is seen, which, if necessary, when the shock absorber ( 10 ) is compressed with the interposition of various pressure ratios, controls the control slide ( 11 ) to carry out a displacement movement. 3. Suspension according to claim 1 or 2, characterized in that the working with the excitation frequency of the strut during compression and rebounding reel slide ( 11 ) has at least three passage cross sections, a first passage cross section ( f ₁ (s)) for the determination the spring stiffness, a second passage cross-section ( f ₂ (s)) for the determination of the damping when the spring deflection ( 10 ) and a third passage cross-section ( f ₃ (s)) for determining the damping when the spring strut rebound. 4. Suspension according to one of claims 1-3, characterized in that the control slide ( 11 ) a lower pressure chamber ( 25 ) and an upper, via a check valve ( 36 ) as a delivery valve to the output pressure chamber ( 34 ) from the control pump ( 12 ) opening Pressure chamber ( 30 ). 5. Suspension according to one of claims 1-4, characterized in that the upper, for the return of the spool ( 11 ) decisive pressure chamber ( 30 ) through a bypass line ( 28 ) with a bypass throttle ( 29 ) with throttle cross-section ( f _bypass ) is connected to the lower pressure chamber ( 25 ) and in addition to this a return line ( 41 ) with a control throttle ( 43 ) is provided in parallel, which opens into the pressure chamber connected to the main pressure line ( 27 ) above or within the drive piston ( 39 ). 6. Suspension according to claim 3, characterized in that the passage cross-sections controlled by the movement of the control slide ( 11 ) ( f ₁ (s) , f ₂ (s), f ₃ (s)) change in the same direction or in opposite directions. 7. Suspension according to claim 3 or 6, characterized in that the first passage cross section ( f ₁ (s)) closes increasingly with an initial stroke movement of the control slide ( 11 ), while the other two cross sections ( f ₂ (s) , f ₃ (s)) increasingly open towards the first passage cross section. 8. Suspension according to claim 5, characterized in that the control throttle ( 43 ) in the return channel ( 41 ) is quickly or slowly continuously or suddenly adjustable. 9. Suspension according to one of claims 1-8, characterized in that in the lower pressure chamber ( 25 ) of the control slide ( 11 ) a biasing spring ( 31 ) for generating a predetermined control slide return force ( K 3 ) is arranged and that the un-pressure chamber ( 25 ) is connected directly to the main pressure line ( 27 ) carrying the system pressure ( p _F ). 10. Suspension according to one of claims 1-9, characterized in that a first storage spring ( 14 ) is provided, which (via a check valve 45 ) with the main pressure line ( 27 ) is connected, and that to influence the spring stiffness, a second additional storage spring ( 15 ) is provided, which has an increasing stroke in its cross section ( f ₁ (s)) reducing passage in the spool ( 11 ) with a spring ( 14 ) leading to the first storage line ( 22 , 23 , 23 ') ver is bound. 11. Suspension according to claim 10, characterized in that a second control throttle ( 24 ) with a variable control cross-section ( f ( β )) is arranged in the connecting line between the two storage springs. 12. Suspension according to claim 11, characterized in that the two storage springs ( 14 , 15 ) connecting to change the spring stiffness connecting second control throttle ( 24 ) is suddenly switchable between two limit values. 13. Suspension according to one or more of claims 1-12, characterized in that with the system pressure ( p _F ) leading main pressure line ( 27 ), optionally via a check valve ( 45 ) consisting of a pump and control valve level control for gradually increasing the system pressure depending on the load condition of the vehicle. 14. Suspension according to one or more of claims 1-13, characterized in that the upper, upon compression with a pressure increase reacting working pressure chamber ( 20 a ) of the shock absorber ( 10 ) via a check valve opening in the lower working pressure chamber ( 20 b ) ( 48 ) is connected directly to the lower working pressure chamber ( 20 b ). 15. Suspension according to one or more of claims 1-14, characterized in that the lower working pressure space ( 20 b ) of the shock absorber ( 10 ) via the main pressure line ( 27 ) and a gradually closing when the control slide ( 11 ) returns to its starting position Passage cross section (f ₃ (s)) is connected to the upper working pressure chamber ( 20 a ) for determining the damping behavior when rebounding. 16. Suspension according to one or more of claims 1-15, characterized in that the memory spring connection point ( 23 ) via a further, in its cross section ver reducing passage (f ₂ (s) when returning to the starting position of the control slide ( 11 ) ) with the intermediate pressure chamber ( 37 ) is connected to determine the damping behavior when the shock absorber ( 10 ) is compressed. 17. Suspension according to one of claims 1-16, characterized in that the piston ( 32 ) of the control pump ( 12 ) acted upon output pressure chamber ( 34 ) with a smaller diameter ( D 2 ) compared to the diameter ( D 1 ) of the drive piston ( 39 ) is connected to the main pressure line ( 27 ) via a check valve ( 35 ) working as a suction valve. 18. Suspension according to one or more of claims 1-17, characterized in that in the drive piston ( 39 ) of the hydraulic drive ( 13 ) for the control pump ( 12 ) a check valve ( 40 ) is seen before, which the intermediate pressure chamber ( 37 ) at this higher pressure in the main pressure line ( 27 ) and that a maximum stroke limitation ( s _p ) for the drive piston ( 39 ) is provided by an annular groove ( 42 ) as soon as this annular groove controls the pressure equalization to the intermediate pressure chamber ( 37 ). 19. Suspension according to claim 18, characterized in that coming from the first control throttle ( 43 ) de connecting line from the upper pressure chamber ( 30 ) of the control slide ( 11 ) in the region of the drive piston ( 39 ) at maximum stroke ( s _p ) of Drive piston ( 39 ) is shut off, with a given overlap ( s _Ü ) for setting the return speed of the control slide ( 11 ). 20. Suspension according to one of claims 1-19, characterized in that a stroke limiter on the control slide ( 11 ) is provided by opening the upper pressure chamber ( 30 ) in the drain line from the switchable second storage spring ( 15 ) while at the same time overlapping the Speicherfe deraufaufs at this passage cross section (f ₁ (s)) . 21. Suspension according to claim 17, characterized in that on the piston ( 32 ) of the control pump ( 12 ) engages a return spring ( 38 ) with a predetermined spring force ( K 2 ). 22. Suspension according to one or more of claims 1-21, characterized in that at least one, the travel, the speed of the deflection, the frequency of the spring movements and other data of the shock absorber ( 10 ) or the vehicle (steering wheel impact, brake pressure) Detecting sensor ( 20 ) is easily seen, the output signals of an electronic control circuit, a computer, a program-controlled microprocessor or the like can be supplied and the possible three external factors, namely pressure increase via the level control and adjustment of the throttle cross sections (f ( α )) and (f ( β )) of the control chokes ( 43 , 24 ) are determined.