WO2005070711A1

WO2005070711A1 - Anti-roll system for a vehicle

Info

Publication number: WO2005070711A1
Application number: PCT/EP2005/050042
Authority: WO
Inventors: Axel Hinz; Christoph Voss; Günther VOGEL; Christian Courth; Axel Nieder-Vahrenholz; Koen Vermolen; Ralf Kaiser; Holger Kollmann
Original assignee: Continental Teves Ag & Co. Ohg
Priority date: 2004-01-21
Filing date: 2005-01-06
Publication date: 2005-08-04

Abstract

The invention relates to an anti-roll system for a vehicle. Said system comprises: at least one actuator for actively influencing the rolling motion of the vehicle; a pump for supplying the actuator with a pressurised hydraulic fluid; a directional valve (1) and a safety valve (6), which are situated between the pump and the actuator in a pressurised supply line (12); a return line (22) for connecting the actuator, when required, to an unpressurised tank; at least one pressure control valve (2); a pressure sensor (7) for adjusting the hydraulic fluid supply to the actuator; and a sensor for detecting the selected position of the directional valve (1). According to the invention, at least one of the aforementioned valves (1, 2, 6) can be hydraulically actuated by the hydraulic fluid that is delivered by the pump, in order to reduce the dimensions of the system, in particular of the solenoid actuators.

Description

Vehicle Stability System.

The invention relates to an active vehicle stabilization system according to the preamble of patent claim 1.

Such a system is known from the lecture "Dynamic Drive - The Roll Stabilization System of the 7 's and the New 5' s" at the "Hydraulics in Motor Vehicles" conference at the Haus der Technik in Essen on November 12/13, 2003.

This system has, inter alia, a hydraulic circuit for the active regulation of chassis components, for which purpose the circuit is connected to hydraulic swivel motors which generate a controllable torque in the transverse stabilizers provided on the front and rear axles of the chassis. The hydraulic circuit is designed for a pump-supported pressure medium supply that is comparable to the flow characteristic of a hydraulic power steering. The valves required to control the pressure and flow direction are integrated in a valve block in connection with a sensor system. Both the directional and safety valve used for this purpose are designed as slide valves that are actuated electromagnetically. The directional valve is designed as an 8/2 level valve and the safety valve as a 4/2 level valve. The slide valve design leads to a large overall length the large amount of construction work required for the magnetic drive is additionally impaired.

It is therefore the object of the invention to improve a vehicle stabilization system of the type specified so that a compact, particularly reliable and responsive hydraulic system is created with as little effort as possible, the valves and the associated actuation of which can be integrated particularly well within a valve block.

This object is achieved according to the invention for a vehicle stabilization system of the type specified with the characterizing features of patent claim 1.

With the proposed solution features of the invention, the prerequisite is created that high flow rates can be maintained at a low dynamic pressure, the mechanical and electrical outlay for the valves is as low as possible, and the desire for a continuously variable pressure control can be fulfilled in the simplest possible way.

Further features, advantages and possible uses of the invention emerge from the subclaims and the description of several exemplary embodiments.

Show it:

FIG. 1 shows the hydraulic circuit diagram for a first expedient embodiment of the invention, which ensures that both swivel motors can be controlled with the least effort,

Figure 2 shows the hydraulic circuit diagram for a second expedient embodiment of the invention, with the least A separate control of both swivel motors ensures effort,

3 shows a separate regulation of both swivel motors according to the circuit principle according to FIG. 2, but using an 8/2-way valve instead of two 4/2-way valves as a directional valve,

FIG. 4 shows a structural embodiment of the directional valve in its unactuated basic position,

FIG. 5 the directional valve according to FIG. 4 in its actuated switching position,

FIG. 6 shows the hydraulic circuit diagram for an expedient embodiment of the invention, which has electromagnetically actuated inlet and outlet valves for the hydraulic actuation of the directional and safety valve,

7 shows an alternative circuit arrangement of the pilot valves and fixed orifices shown in FIGS. 1-3 for hydraulic actuation of the directional and safety valve,

8 shows a combination of the features known from FIGS. 6 and 7, which provide for the actuation of the safety valve, the combination of an inlet valve with an orifice and for the actuation of the directional valve, the combination of inlet and pilot valve on a control pressure line,

FIG. 9 shows an expedient embodiment of the invention by hydraulic action of the directional valve on both sides in opposite directions for hydraulically initiated actuation of the directional valve. valve in the basic as well as in the switch position,

FIG. 10 shows a structural embodiment of the directional valve presented in FIG. 9, which is in its hydraulically initiated basic position,

11 shows the directional valve according to FIGS. 9, 10 in its hydraulically operated changeover position,

12 shows a circuit variant of FIG. 9 for the hydraulic actuation of the directional valve.

FIG. 1 shows the hydraulic circuit diagram for a vehicle stabilization system, in particular for roll stabilization, the valves 1, 2, 3, 4, 6, 10 of which are integrated in a schematically illustrated valve block 17 in connection with the hydraulic pressure medium paths. The hydraulic circuit diagram comprises a considerably simplified circuit design for the synchronous hydraulic actuation of two actuators, which are designed as swivel motors arranged on the transverse stabilizers of the front and on the rear axle of a vehicle, the chambers VI, V2 and Hl, H2 of which are acted upon hydraulically, in order to be able to variably adjust the torsional stiffness of the anti-roll bars to actively influence the rolling motion of the vehicle.

The hydraulic circuit according to FIG. 1 accordingly has a pump connection P for a pump on the valve block 17, with a pump pressure line 9 on the pump connection to which a pressure sensor 7 is connected. The pump pressure line 9 is connected to a tank connection T within the valve block via a proportionally actuatable pressure control valve 2 which is open in the basic position. The tank connection T leads outside the valve block to an unpressurized tank from which the pump coupled to the steering system takes the pressure medium required for chambers VI, V2, Hl, H2 of the two actuators. Between the pressure control valve 2 and the tank connection T, two line branches 11 provided with check valves 10 are connected within the valve block 17 to the pump pressure line 9, which lead to the chambers VI, V2, Hl, H2 of the two actuators (swivel motors) which can be connected to the valve block. In the simplest design, the two check valves 10 are designed as spring-loaded ball check valves that open exclusively in the direction of the chambers VI, V2, Hl, H2, in order to ensure that the chambers are refilled at all times to avoid cavitation in the chambers VI, V2, Hl, H2 ,

Between the pressure control valve 2 and the pump connection P, a pressure supply line 12 is connected to the pump pressure line 9, into which a directional valve 1 is inserted, which in its basic position connects the pressure supply line 12 to the tank connection T via a downstream safety valve 6. The directional valve 1 and the safety valve 6 are designed as easy-to-manufacture 4/2-way valves in slide valve construction, which are actuated hydraulically according to the invention. The hydraulic actuation of the directional and safety valve 1, 6 takes place within the valve block 17 by means of two pilot valves 3, which are connected between the pump connection P and the pressure control valve 2 to two line branches 13 of the pump pressure line 9. The two line branches 13 have upstream of the two pilot valves 3 within the valve block orifices 5, between which and the two pilot valves 3 two control pressure lines 14 are connected for hydraulic actuation of the directional and safety valve 1, 6.

In the mechanically open basic position of the two pilot valves 3, a blocked partial flow of the pump Pressure line 9 via a return line 22 to the tank connection T, so that the two control pressure lines 14 are depressurized and the directional and safety valve 1, 6 remain in the basic position shown, in which the safety valve 6 keeps the chambers VI, V2, Hl, H2 pressure supply line 12 separate ,

To act upon the actuators hydraulically, the directional and safety valve 1, 6 is hydraulically switched by the pump pressure in the two control pressure lines 14 as soon as the two pilot valves 3 electromagnetically assume their blocking position. In this changeover position of the directional valve 1, which is hydraulically initiated by the dimmed pump pressure, the pump pressure simultaneously passes via the pump pressure line 9 to the pressure supply line 12 and to the safety valve 6 which is hydraulically switched to passage, which in the present example connects the pressure supply line 12 to the two chambers V2, H2 of the swivel motors, while the two chambers VI, Hl are connected to the unpressurized tank connection T via the safety valve 6, the directional valve 1 and the pressure control valve 2.

On the one hand, due to the hydraulic loading of the chambers V2, H2 and the hydraulic relief of the chambers VI, Hl, in the present exemplary embodiment, each of the two swivel motors rotates a rotary body which is mechanically connected to one of the two transverse stabilizers for variable adjustment of the torsional rigidity.

The switch position detection of the directional valve 1 is carried out by a displacement sensor 15 attached to the valve block 17, which prevents the safety valve 6 from being hydraulically switched to the open position in the event of an electrical or mechanical malfunction relevant to the directional valve 1. In the event of a malfunction then remains the pressure medium volume just enclosed in the chambers VI, V2, Hl, H2 exists due to the blocking effect of the safety valve 6 and the blocking effect of the check valves 10, the chambers VI, Hl, via the direction-dependent blocking effect of the two check valves 10 to avoid cavitation in the actuators. V2, H2 can be supplied with regulated pump pressure.

For sensitive, needs-based control of the pump pressure, the pressure control valve 2 can be actuated hydraulically continuously via a further pilot valve 4 connected to a line branch 13 of the pump pressure line 9. This further pilot valve 4, which is connected downstream of an orifice 5, differs in the use of a proportional magnet from the two binary switching pilot valves 3 already explained in connection with the directional and safety valve 1, 6, so that a proportional hydraulic control pressure can be set via the line branch 13, which The pressure control valve 2 is continuously operated via a control line 14. In the preferred embodiment, the position of the pressure control valve 2 which reduces or blocks the passage of liquid is realized particularly simply with the aid of a spring, as long as no pressure difference acts on the pressure control valve 2 via the pressure in the pump pressure line 9.

FIG. 2 shows, starting from the elementary hydraulic circuit according to FIG. 1, a suitable extension of the valve arrangement already described in FIG. 1 for the purpose of individually regulating the hydraulic pressure in the two chambers VI, V2 of the front swivel motor and in the chambers Hl, H2 of the rear swivel motor, for which purpose the chambers VI, Hl and V2, H2 are connected to two independent pressure supply lines 12, so that in addition to the pressure supply line 12 already described in FIG. 1, a further pressure supply line 12 flows upstream. nem another pressure control valve 2 is connected to the pump pressure line 9. In this further pressure supply line 12, only a further directional valve 1, which is identical in construction to the first directional valve 1 (see FIG. 1) and is advantageously connected to the control pressure line 14 of the first directional valve 1 for its hydraulic actuation, is inserted.

Both pressure control valves 2 ensure that reactions of the roadway can be hydraulically corrected via the cross stabilizers on the actuators in the chambers V2, H2.

The switching position of the further directional valve 1 is monitored analogously to the first directional valve 1 by an additional displacement sensor 15. An additional pressure sensor 7 is also provided for the pressure monitoring in the further pressure supply line.

In the exemplary embodiment according to FIG. 2, only the pressure supply of the chambers VI, V2 of the swivel motor arranged on the front axle of the vehicle is preferably provided with a safety valve 6, which keeps the chambers VI, V2 separate from the pressure supply of the pump and from the return to the tank in the event of a malfunction in the roll stabilization system , because it can then not be operated hydraulically due to the open position of the associated pilot valve 3. The effect of the front axle stabilizer is thus ensured in the event of a malfunction of the roll stabilization system due to the blocking effect of the safety valve 6.

Insofar as all details have not previously been given in detail for FIG. 2, these correspond to the illustrated embodiment according to FIG.

In contrast to the exemplary embodiment according to FIG. 2, FIG. 3 shows the structural union of those known from FIG two directional valves 1 to a single directional valve 1, which is designed as an 8/2-way valve in slide valve type. The structure of the hydraulic circuit diagram according to FIG. 3 otherwise corresponds to the hydraulic concept according to FIG. 2, in particular with regard to the hydraulic control of the directional and safety valves 1, 6 and the design of the pressure control and pilot valves 2, 3, 4.

The design of the directional valve 1 according to FIG. 3 as an 8/2-way valve only requires a single displacement sensor 15 to monitor the slide position; on the other hand, this valve design places high demands on the precision of the slide, so that in practice there are advantages in terms of production technology by dividing the 8th Draw the 2-way valve on two 4/2-way valves.

In this connection, FIG. 4 shows an expedient structural embodiment for the directional valve 1 known from FIG. 3 in a longitudinal section. The directional valve 1 has as essential components a two-part, metal-sealed hollow slide 16, which is inserted concentrically from two diametrical sides into a light metal valve block 17 in such a way that the directed towards each other hollow slide ends. The step bore 18 required for this purpose, which is introduced from both sides of the block, and the bushings 19 used therein for low-wear guiding of the two-part hollow slide 16 can be produced relatively shortly and with little manufacturing effort from diametrical manufacturing directions in the valve block 17 by the concept shown.

FIG. 4 shows the two-part hollow slide 16 in the unactuated basic position of the 8/2 directional valve known from FIG. 3, for which purpose a compression spring 20 arranged on the left outer end of the hollow slide pushes the hollow slide 16 onto the right cover-shaped housing stop 21 of the valve block 17 presses. As a result, the channel bore for the pump connection P (DRV-H) which opens into the stepped bore 18 transversely to the hollow slide axis is connected along the outer jacket of the left hollow slide part to the channel bore in the valve block 17 leading to the chamber H1 of the swivel motor, while the further chamber H2 of the swivel motor is connected via the transverse bores arranged in the end region of the left-hand hollow slide part are connected to the channel bore in valve block 17 leading to tank connection T.

An identical flow pattern results when looking at the right-hand hollow slide part, so that, apart from the special feature already shown in FIG. 3 for using the safety valve 6 between the right-hand hollow slide part and the chambers VI, V2, the flow in the right hollow slide part is mirror-symmetrical to the flow in the left hollow slide part Consideration corresponds.

In FIG. 5, the directional valve 1 is shown in the hydraulically actuated changeover position of the two-part hollow slide 16, after which the hollow slide 16 counteracts the effect of the control valve in the control bore P (PILOT), which acts on the right piston surface of the hollow slide 16 Compression spring 20 is shifted to the left so that, for example, the channel bore leading to the chamber Hl is hydraulically connected to the channel bore leading to the tank connection T in the valve block 17 via the transverse bores arranged at the right end of the left bushing 19. At the same time, the channel bore in the valve block 17 connected to the chamber H2 is also hydraulically connected along the outer jacket of the left-hand hollow slide part to the channel bore leading to the pump connection P (DRV-H).

The same statements made so far regarding the flow through the directional valve 1 also apply in principle to the right-hand hollow slide part, with the difference that Instead of the chambers Hl, H2, the chamber VI is hydraulically connected to the tank connection T and the chamber V2 is connected to the pump connection P (DRV-V).

In order to fulfill the simple flow of the directional valve 1 explained so far, the channel bore leading to the tank connection T is arranged on the vertical Spiegelach.se of the two hollow slide parts. At a distance from the mirror axis to the left and right side progressing to the central symmetrical channel bore of the tank connection T, the channel bores for the chambers H1 and V2, for the pump connections P (DRV-H) and P, open to the left and to the right side of the mirror axis (DRV-V), and the chambers H2 and VI each from above into the valve block 17.

Based on the hydraulic circuit diagrams of FIGS. 1 to 3, FIG. 6 shows an alternative embodiment for the hydraulic actuation of the directional and safety valve 1, 6, in that instead of fixed orifices 5 (see FIGS. 1-3) now closed 2/2 in the basic position Directional inlet valves 8 are used which, like the already explained pilot valves 3 which are open in the basic position, are switched electrically or electromagnetically.

Consequently, the hydraulically switchable safety valve 6 and the directional valve 1 are each hydraulically actuated via the control pressure line 14 opening between an inlet valve 8 and a pilot valve 3 as soon as the two pilot valves 3 are closed electromagnetically and the two inlet valves 8 are opened electromagnetically. In the simplest embodiment, the safety and directional valve 6, 1 is returned to the basic position automatically by a pair of compression springs as soon as the spring-assisted return of the inlet and pilot valves 8, 3 to their basic position as a result of the interruption of the electromagnetic excitation return. In the simplest form, the inlet and pilot valves 8, 3 are designed as fast-switching 2/2-way seat valves, which are advantageously designed for a low volume throughput. Otherwise, the basic circuitry arrangement and control of the other hydraulic components, such as pressure control valves 2, check valves and pilot valves 4, remain unchanged from the previous embodiments.

Finally, FIG. 7 shows a further variant for the hydraulic actuation of the safety and directional valve 6, 1, in that the two orifices 5 downstream of the two control pressure lines 14 and downstream of the two inlet valves 8 in reverse to that from the previous circuit diagrams according to FIG. 1-3 known hydraulic bridge circuit are arranged. The two inlet valves 8 are designed as fast-switching, normally closed solenoid valves in the 2/2-way seat valve type. Otherwise, the circuit structure according to FIG. 7 corresponds in all further details to the previously described FIGS. 3, 6.

FIG. 8 discloses a combination of the features known from FIGS. 6 and 7 for the hydraulic actuation of the safety valve and the directional valve, for which purpose the control pressure line 14 on the safety valve 6 corresponding to the hydraulic circuit according to FIG. 7 between an inlet valve 8 which is closed in the basic position and an orifice plate 5 is either connected to the return line 22 or to the pump pressure line 9, while the control pressure line 14 on the directional valve 1 according to FIG. 6 is connected to the pump pressure or return line 9, 22 via an inlet and a pilot valve 8, 3. All other details of FIG. 8 can be found in the previous exemplary embodiments. In contrast to the previous exemplary embodiments, FIG. 9 shows an expedient embodiment of the invention, according to which the directional valve 1 is moved exclusively by hydraulic initiation into the basic position shown in the figure or into the opposite position by means of a reciprocal hydraulic action. The basic positioning of the directional valve 1 known from the preceding FIGS. 1-8 and maintained by means of the compression spring 20 is thus eliminated since the directional valve 1 has a further actuating piston 23 which can be connected to the pump pressure line 9 via a further control pressure line 14.

Deviating from FIG. 6, there is therefore, according to FIG. 9, upstream of the further control pressure line 14 preferably a pilot valve 3 which is open in the basic position in a line branch 13 connected to the pump pressure line 9 and downstream of the further control pressure line 14 an outlet valve 24 which is closed in the basic position and which is a switchable connection of the other Control pressure line 14 with the return line 22 allows.

In the illustrated blocking position of the outlet valve 24, the directional valve 1 remains in its basic position, since the pump pressure via the open pilot valve 3 and the downstream control pressure line 14 acts unhindered on the right actuating piston 23 on the directional valve 1, while the left actuating piston 23 of the directional valve 1 as a result of the blocking position of the inlet valve 8 is separated from the pump pressure and is connected to the unpressurized return line 22 via the pilot valve 3 downstream of the inlet valve 8.

To switch the directional valve 1, the inlet valve 8, the two pilot valves 3 and the outlet valve 24 are excited electromagnetically, so that, on the one hand, the hydraulic actuation of the left actuating piston 23 Inlet valve 8 assumes its open switching position and the pilot valve 3 arranged downstream of the inlet valve 8 assumes its closed position, on the other hand the pilot valve 3 arranged upstream of the outlet valve 24 is closed and the outlet valve 24 is opened in order to relieve pressure from the right actuating piston 23.

The hydraulic actuation of the directional valve 1 according to the previous exemplary embodiment according to FIG. 9 is independent of the selected embodiment as an 8/2 or 4/2 way valve.

In FIG. 12, the hydraulic actuation of the directional valve 1 according to the exemplary embodiment according to FIG. 9 is simplified in that the two pilot valves 3 known from FIG. 9 and the outlet valve 24 are replaced by fixed shutters 5. However, this simplification in terms of circuitry means that the actuation of the directional valve 1 is somewhat delayed and the hydraulic volume requirement for actuating the directional valve 1 increases.

By means of the hydraulic actuation of the directional valve 1 on both sides, shown in FIGS. 9, 12, in its basic as well as in the changeover position, in contrast to the use of the compression spring 20 for basic valve positioning in both valve directions, precise switching sequences with minimal switching times for the directional valve 1 can be realized.

Unless all the details of FIGS. 9, 12 have been explained so far, they correspond to the previous exemplary embodiments according to FIGS. 1 to 8.

FIG. 10 shows an expedient constructive embodiment for the directional valve 1 known from FIG. 9 in a longitudinal section. The directional valve 1 has as essential components a two-part, metallic sealed th hollow slide 16 which concentrically diametrical two sides in a light-metal valve block 17 is inserted so that the contact _r on each other directed hollow spool ends. The step bore 18 required for this purpose, which is introduced from both sides of the block, and the bushings 19 used therein for low-wear guiding of the two-part hollow slide 16 can be produced relatively shortly and with little manufacturing effort from diametrical manufacturing directions in the valve block 17 by the illustrated concept. The valve position is monitored by a displacement sensor 15 inserted into the valve block 17 at one end of the directional valve 1.

FIG. 10 shows the two-part hollow slide 16 in the unactuated basic position of the 8/2 directional valve known from FIG. 9, for which purpose hydraulic pressure effective at the left outer end of the hollow slide (actuating piston 23) presses the hollow slide 16 against the right wire ring-shaped stop of the bushing 19 , As a result, the channel bore for the pump connection P (DRV-H) which opens into the stepped bore 18 transversely to the hollow slide axis is connected along the outer jacket of the left hollow slide part to the channel bore in the valve block 17 leading to the chamber H1 of the swivel motor, while the further chamber H2 of the swivel motor is connected via the transverse bores arranged in the end region of the left hollow slide part to the channel bore leading to the tank connection T in the valve block 17.

An identical flow pattern results when the right-hand hollow slide part is viewed, so that, apart from the special feature already shown in FIG. 9 for the use of the safety valve 6 between the right-hand hollow slide part and the chambers VI, V2, the flow course in the right hollow slide part is mirror-symmetrical to the flow course in the left hollow slide part Consideration corresponds. In this shown basic position of the directional valve 1 is the right hollow slide in the function of the right actuating piston 23 hydraulically pressureless.

In a departure from FIG. 10, the two-part hollow slide 16 is shown in the hydraulically actuated switch position in FIG. 11 because, due to the hydraulic pressure relief of the left hollow slide end face (left actuating piston 23), a control pressure present in the right control bore P (PILOT) on the piston surface of the right hollow slide 16 is effective, which presses the two-part hollow slide 16 against the left spring ring-shaped stop. In this way, for example, for the left-hand hollow slide part, the channel bore in valve block 17 leading to chamber H1 of the actuator is hydraulically connected to the channel bore in valve block 17 leading to tank connection T via transverse bores 19a, 19b. At the same time, the channel bore in the valve block 17 connected to the chamber H2 is hydraulically connected to the channel bore leading to the pump connection P (DRV-H) along the outer jacket of the left-hand hollow slide part and the transverse bores 19c, 19d. A structurally and functionally similar flow connection results in the illustrated switching position of the directional valve 1 via the transverse bores of the right-hand liner to the pump connection P (DRV-V) and to the channel bores in the valve block 17, which are provided on the chambers VI, V2 of the further actuator ,

Unless all the details shown in FIGS. 10, 11 have been dealt with so far, these can be found in the explanations of FIGS. 4, 5.

In summary, the invention discloses the following features worthy of mention:

A hydraulic circuit for a vehicle stabilization system is proposed, the safety, restraint and tion and pressure control valves 6, 1, 2 are pilot-controlled by pilot valves 3, 4, preferably in combination with fixed orifices 5, in the manner of a bridge circuit.

The directional valve 1 is designed as an 8/2 or 4/2 directional control valve in the spool design and the safety valve 6 as a 4/2 directional control valve, which no longer has to be adjusted by electromagnets. For the quick-switching actuation of the directional and safety valve 1, 6, the pilot valves 3,, have a flow rate that is as small as possible, for which purpose particularly small, quick-switching 2/2-way seat valves are used, such as those used in ABS / ESP brake systems ,

To actuate the closing bodies of the proportionally actuatable pressure control valves 2, which are preferably designed as seat valves, pilot valves 4 are provided which act analogously and each exert a hydraulic pressure proportional to the electric current in the pilot valve coil on the closing body of the pressure control valve 2 to be actuated, the pilot valve 4 being used to control it Hydraulic pressure is advantageously reduced by the pressure value resulting from the area ratio on the closing body. The current at the solenoid of the pilot valve 4 forms the manipulated variable with which the system pressure in the chambers VI, V2, Hl, H2 can be varied hydraulically in the closed control loop on the basis of the signal from the pressure sensor 7 on the pressure supply lines 12.

In the present exemplary embodiment, the actuator of the roll stabilization system consists of a swivel motor for each vehicle axle, which has two pressure medium connections per chamber for the hydraulic loading of its two chambers VI, V2 or Hl, H2, each pressure medium connection at the chambers VI, V2 or Hl, H2 via the cattle tion valves 1 is either connected to a pump connection P or to a tank connection T.

In order to be able to actively influence both the roll movement on the front and on the rear axle of the vehicle, there is an actuator both on the front and on the rear axle, both of which are actuated via at least one hydraulically pilot-controlled directional valve 1. The pressure supply required for this is provided by a pump at its pump pressure connection P. According to FIGS. 2, 3, 6, 7, the control of the pump pressure for each actuator 6 takes place individually via a pressure control valve 2, which is actuated in a hydraulically proportional manner depending on the switching position of an electrically proportioned pilot valve 4. The sequence of the pressure control and pilot valves 2, 3, 4 opened in the basic position leads to a tank connection T, from the tank of which the pump P takes the required pressure medium.

The concept of the invention allows at least one of a plurality of vehicle axles, preferably at least the front axle, to be actively influenced in order to reduce the vehicle roll movement.

In order to be able to actively influence both the roll movement on the front and on the rear axle of the vehicle in a particularly simple yet effective manner, FIG. 1 shows, in contrast to the other embodiments, a hydraulic circuit for a vehicle roll stabilization system, in which only one only 4/2-way valve designated as directional valve 1, the actuators of the front and rear axles can be actively influenced together in the manner on which the invention is based.

The pilot valves 3, 4 in the form of 2/2-way seat valves have the advantage, among other things, that they are particularly small and compact, for example as cartridge valves, arranged on a single side of a valve block and can be connected according to the principle of the magnetic connector to an electronic controller required to control the valves.

As can be seen from FIGS. 1-7, the invention offers good conditions for using both normally closed and normally open, small-sized pilot valves 3 for controlling the directional valves 1. Moreover, instead of the normally open pressure control valves 2, normally closed valves can also be closed Use pressure control valves 2, for which it is only necessary to swap positions between the pilot valves 4 and the associated fixed orifices 5.

In some examples, the directional valves 1 are preferably designed as 8/2 slide valves, which in a simplified construction can also be produced as two 4/2 slide valves, as is explicitly shown in FIG. 2.

Reference character list

1 directional valve 2 pressure control valve 3 pilot valve 4 pilot valve 5 fixed orifice 6 safety valve 7 pressure sensor 8 inlet valve 9 pump pressure line 10 check valve 11 line branch 12 pressure supply line 13 line branch 14 control pressure line 15 displacement sensor 16 hollow slide valve 17 valve block 18 stepped bore 19 bushing 20 pressure spring 21 housing stop 22 return line 23 actuating piston 24 outlet valve

Claims

claims

1. Vehicle stabilization system, with at least one actuator for actively influencing the vehicle movement, in particular the vehicle roll movement, with a pump for supplying pressure to the actuator with pressure medium, with a directional valve for connecting at least one chamber of the actuator either with a pressure supply line connected to the pump or with a return line, which is connected to a pressure-free tank, with at least one pressure control valve and a pressure sensor for regulating the supply of the actuator with the pressure medium of the pump, and with a safety valve that separates the actuator from the pressure supply line when a system error occurs, characterized in that at least one the aforementioned valves (1, 2, 6) can be actuated hydraulically by means of the pressure medium conveyed by the pump.

2. Vehicle stabilization system according to claim 1, characterized in that the hydraulic actuation of at least one of the valves (1, 2, 6) takes place either by means of a digital or analog actuating movement of a hydraulically actuated actuating piston (23), which is an integral part of one of the aforementioned valves (1, 2, 6).

3. Vehicle stabilization system according to claim 1 or 2, characterized in that the hydraulic actuation of at least one of the aforementioned valves (1, 2, 6) takes place depending on the switching position of an electrically actuated pilot valve (3, 4), which in combination with an orifice (5) forms a bridge circuit via which the pressure of the pump can be supplied to at least one of the aforementioned valves (1, 2, 6).

4. Vehicle stabilization system according to claim 3, characterized in that the pilot valve (3, 4) is designed as a 2/2-way valve, which is preferably designed in a poppet valve design and can be actuated either electromagnetically or piezoelectrically.

5. Vehicle stabilization system according to one of the preceding claims, characterized in that the pilot valve (4) for the stepless hydraulic actuation of the pressure control valve (2) is provided with a proportional magnet.

6. Vehicle stabilization system according to one of the preceding claims 1 to 4, characterized in that the pilot valve (3) for digital actuation of the directional as well as the safety valve (1, 6) has a switching magnet, the pilot valve (3) either with electromagnetic excitation holds in the fully open or fully closed switch position.

7. Vehicle stabilization system according to one of the preceding claims 1 or 2, characterized in that the hydraulic actuation of the directional as well as the safety valve (1, 6) in at least one of the possible switching positions depending on the switching position of an inlet valve cooperating with the pilot valve (3) (8), which is arranged hydraulically in series with the pilot valve (3).

Vehicle stabilization system according to claim 7, characterized in that between the pilot valve (3) and the inlet valve (8) a control pressure line (14) is connected to a pressure medium path connected to the pump, the piston for actuating (23) the direction and / or the Safety valve (1, 6) leads, the directional and / or safety valve (1, 6) being hydraulically depressurized when the pilot valve (3) is in the open position and the inlet valve (8) is in the closed position at the same time.

9. Vehicle stabilization system according to claim 8, characterized in that in the open switching position of the inlet valve (8) and at the same time the closed pilot valve (3) the actuating piston (23) of the directional or safety valve (1, 6) via the control pressure line (14) from the pressure the pump is loaded.

10. Vehicle stabilization system according to one of the preceding claims, characterized in that in the open switching position of the pilot valve (3, 4) the actuating piston (23) via the control pressure line (14) with the return line leading to the tank (22) is connected.

11. Vehicle stabilization system according to one of the preceding claims, characterized in that the flow cross-section of the pilot valve (3, 4) is smaller than the flow cross-section of the directional and / or the safety valve (1, 6).

12. Vehicle stabilization system according to claim 11, characterized in that the flow cross-section of the safety valve (6) is the size of the flow cross-section of the directional valve (1) adapted.

13. Vehicle stabilization system according to one of the preceding claims, characterized in that the area of the actuating piston (23) acted upon by the pressure of the pump is dimensioned such that the actuating piston (23) is the safety and / or Directional valve (6, 1) can be switched with reduced pump pressure.

14. Vehicle stabilization system according to one of the preceding claims, characterized in that the pilot valve (4) provided for the stepless actuation of the pressure control valve (2) adjusts a hydraulic pressure proportional to the electrical excitation on the actuating piston (23) of the pressure control valve (2) by means of current-proportional electrical excitation ,

15. Vehicle stabilization system according to claim 7, characterized in that the inlet valve (8) are designed as piezoelectrically or electromagnetically actuable 2/2-way valves in the poppet type.

16. Vehicle stabilization system according to one of the preceding claims, characterized in that the respective upstream of the pilot valves (3, 4) orifice (5) is designed as a fixed orifice.