DE10122542A1 - Device for regulating movements of the body of motor vehicles - Google Patents

Abstract

The invention relates to a device for regulating the movements of the superstructure (12) of a motor vehicle, whereby said superstructure (12) is supported directly or indirectly by a serially connected active actuating member (1) and a supporting spring (21) on at least a wheel axle. The actuating member (1) is formed from an electromechanical drive.

Description

The invention relates to a device for avoidance undesirable movements in the construction of motor vehicles. The standard for this are between the wheel axle and the body of the Motor vehicle arranged springs that the movement of the wheels oppose a growing force against building. Faster vibrations are coupled by the springs Dämpfar eliminated or at least greatly reduced.

Systems for changing the Height or the distance of the body over the road. For this it is known for vehicles with steel springs Level control usually in the shock absorber integrate. The shock absorber can also automatically and caused by the vertical vehicle movements up to desired control height in the vehicle body can be pumped up. In vehicles with air springs, the regulation of the Realize height by using the air springs Load via corresponding external sensors a larger Receive pressure medium quantity. It is also known at Vehicles with hydropneumatic suspension Height control using a hydraulic actuator to realize. However, all of these known systems serve exclusively the regulation of the height of the body the height of the vehicle body above the ground. The distance the structure above the carriageway changes with a change the payload, so that the known systems mentioned  are designed, the corresponding control process extremely perform slowly, with an appropriate control process can last from several seconds to minutes. A Adjustment of dynamic load fluctuations, for example as an impact on the current driving condition or on fast-moving body movements (for example, vibrations that build up) is included impossible with these known systems.

Even if you use the known systems quickly Wanted to interpret control processes, he would stand for this the necessary energy and power requirements are hardly available. Theoretically allow fully active hydraulic Chassis systems an optimal chassis control in terms of driving comfort and handling of the vehicle. she turn out to be from a cost point of view as unrealistic and even if the Power saving additional components are provided, very high Performance requirements.

From DE-AS 26 04 809 it is for an adjustable Suspension system for vehicles known the Harden spring stiffness, which improve the Stability or controllability of the vehicle is used.

Furthermore, reference is made to DE-OS 37 38 284, which describes an active chassis control for motor vehicles, which builds on the basis of known level regulations and a first one depending on the relative deflection acted upon active actuator for the Level control system and a second active actuator in the form of an active or a semi-active damper  between wheel suspension and vehicle body includes. On such a system has a very high energy requirement.

Finally, it has become known from EP-PS 444278 for Regulating the movement of a vehicle body using a spring element to be connected in series with an actuator, this Series connection additionally a suspension spring between Vehicle body and wheel axle is connected in parallel.

The invention is therefore based on a device genus resulting from the preamble of claim 1. The object of the invention is a simple and specify effective device through which a quick active control of the movements of the vehicle body for a Increasing vehicle stability is possible. Task of The invention is also to provide a shock absorber, which Particularly suitable for simple and quick regulation is.

The task is, on the one hand, the result of the characterizing part of claim 1 resulting Combination of features solved. The invention is in principle So in an active regulation of the movements of the Vehicle body an electromechanical actuator use the necessary mechanical Can perform positioning movements very easily and quickly, such an actuator being comparatively inexpensive is. On a hydraulic actuator with elaborate Pipes, storage and pumps can thus be dispensed with become.

The invention is a surprisingly simple way  dynamically active suspension control created without hydraulic pressure supply needs. Based on the Invention can also be achieved that the Energy consumption is minimized and comfort is increased. at the system according to the invention forms an electromechanical Drive an active spring damper system, which with its Drive is and as an additional, in the vehicle Units to be accommodated are only electrical Power supply and electrical control required. The hydraulically independent damper can be retained.

A particularly simple structure for the actuator results from the combination of features listed in claim 2. there is a comparatively inexpensive electric motor in the Inserted the area of construction that covers the supports device according to the invention on a wheel axle. This electric motor drives a threaded spindle on its Thread a non-rotatably arranged and axially movable Threaded screw is seated. If the spindle turns, it moves Screw up and down, changing the altitude of the Construction. The motor and the spindle driven by it react very quickly to corresponding actuation signals so that the arrangement described is very good for dynamic Regulation of the movements of the vehicle body is suitable. However, if the vehicle has a hydraulic power pack, for example for a power steering, it can be under Circumstances recommend a for driving the actuator hydraulic drive to choose.

To energy in the movement of the construction through the Saving the electric motor is recommended in further training at Invention the combination of features according to claim 3. By the  Relief spring, which is preferably set in such a way that with its coils not standing on the block, the Thread largely free of contact forces due to the structure the vehicle stops, it becomes possible that by the actuator only the dynamic movements of the superstructure can be effected have to. The thread remains largely from the Contact forces of the structure spared. However, it is necessary that with downward movements of the body the actuator work against the force of the relief spring got to. The spring should be set so that in the force to be exerted by the motor in both directions is the same is great.

Active chassis control systems are intended to reduce or completely compensate pitch and roll movements of the vehicle body by means of control interventions. To do this, each of the four actuators must be able to raise its vehicle corner. The necessary lifting work is the integral of (adjustment force × adjustment path). If the actuator is relieved of the purely static force component, only a fraction of the energy has to be used during control interventions. Therefore, as shown in Fig. 2, it is proposed according to claim 3 to use parallel to the actuators relief springs ( 6 ), which are statically matched so that the actuators ( 1 ) are relieved when the vehicle is at rest.

A further improvement can thus be seen in the application achieve the features of claim 4 where the use of Gas springs for the suspension spring or the relief spring is proposed. Gas springs offer compared to steel springs one, higher suspension comfort. In addition, a static  Deflection, for example caused by a Weight increase due to payload, by supplying air be compensated. The special advantage of gas springs (Steel springs) is that the own frequency of the Spring mass system is almost independent of the payload.

The system shown in Fig. 3 thus has gas springs ( 7 ), which offer a higher suspension comfort compared to steel springs. In addition, a static deflection, for example caused by an increase in weight as a result of an additional load, can be compensated for by the supply of air (level control). The special advantage of gas springs over steel springs is that the natural frequency of the spring-mass system is almost independent of the payload.

When representing a regulation of the vertical dynamics under Using air springs gives you the option of treble the air columns of an air suspension system by supplying and removing additional air not only quasi-static in the sense of a Level regulation, but also to regulate dynamically. On such an approach has so far proved to be little proven to be workable since the speed of sound in air a physical limit for those at fast High amplitude control operations required Flow speed in the pneumatic feed lines forms. In order not to come near this limit unacceptably large supply cross-sections are chosen.

It is therefore proposed that the upper end of the gas springs ( 7 ) z. B. formed as a plate ( 9 ) adjustable by actuator ( 1 ), as shown in Fig. 4. It is advantageous to use an electromechanical drive ( 1 ), but if a hydraulic unit, for example for a power steering, is already present in the vehicle, the hydraulic drive may also be an inexpensive variant. In any case, it is advantageous to use the actuator relief spring ( 6 or 8 ) to reduce energy consumption. All advantages are combined in a system that uses both gas suspension springs ( 7 ) and gas actuator relief springs ( 8 ) ( FIG. 4), with both gas springs either being able to supply or remove air independently of one another or one of these springs, the another gas spring can be connected to this via an electrically controllable pneumatic valve. The electromechanical drive ( 1 ) can preferably be accommodated within the actuator relief gas spring 8 .

To regulate a chassis equipped with the struts according to the invention, at least the sensor information about the spring deflection is necessary. For this purpose, the struts according to the invention are equipped with displacement sensors ( 10 ). Furthermore, sensors can also be provided for the actuator paths. Both sensor systems can be combined in the spring strut to form a sensor unit. In addition, the pneumatic pressures in the gas springs can also be sensed to determine the exact system status. In an advantageous development of the invention, the use of the features listed in claims 9 and 10 is therefore recommended.

The system presented here combines the advantages of the technically mature pneumatic system for active Chassis level control and the efficiency, design  and power density optimized electromechanical Actuators to a fully active chassis control system with minimal energy consumption. Electrical energy is only in in a medium dynamic range. Very fast Compression is carried out by the conventional hydraulic Damper intercepted, slow operations by a pneumatic Level control system. The middle one, from the Electromechanical actuators covered area concerns especially the adjustment of roll, pitch and lifting movements of the Vehicle, such as when cornering, accelerating and Braking and driving over bumps occur.

Previous approaches to active chassis control are regularly failed due to excessive energy consumption because was mostly attempted to use a too wide dynamic range to cover energy-consuming actuators. The proposed system, however, leaves the area higher Dynamics in which every active system is energetically overwhelmed would be a passive damper and the low dynamic range the level control, which once set no more Energy supply needed. Also the energy needs in the area medium dynamic, in which is actively regulated by the Use of the (preferably pneumatically adjustable) Actuator relief springs minimized. That of dynamic passive gas spring systems known optimal suspension comfort remains in full even with active chassis control receive.

For the color of an active chassis control with minimal Energy consumption are based on a vehicle pneumatically level adjustable chassis only the Struts against the ones presented here additionally electrically  exchangeable, sensors and control electronics add. There are no other units in the vehicle chassis accommodate. The system can also be retrofitted without major problems are inserted into a vehicle.

The solution to the problem of the invention with regard to Shock to consists in that listed in claim 11 Combination of features. Advantageous further training in the invention result from subclaims 11 to 27.

Exemplary embodiments of the invention are described below the drawing explained. It shows:

Figure 1 is a provided with a steel spring made of spring supporting apparatus according to the invention and which belongs to this apparatus strut.

FIG. 2 shows the device or shock absorber according to FIG. 1, in which a relief spring was additionally inserted;

Fig. 3 shows a device or strut corresponding to Fig. 1, in which the steel spring has been replaced by a gas spring and

Fig. 4 shows the embodiment of FIG. 2, in which both the suspension spring and the relief spring are formed by gas springs.

Fig. 1 shows a support 12 on which the structure of the vehicle in Fig. 1 can be directed downward. The pad 12 sits on rubber buffers 13 on a motor housing 14 which receives an electric motor 15 as an electromechanical drive 1 . The motor is anchored with its poles 16 in the motor housing 14 . The rotor of the motor is optionally connected in one piece to a threaded spindle 17 , on the ball thread 18 of which a threaded screw 19 is non-rotatably but axially movable. If the threaded spindle 17 is rotated in one of two directions by the electric motor, the threaded screw 19 moves up or down. Balls are inserted between the thread of the threaded screw and the threaded spindle, which together produce a ball gear. If, for example, the threaded spindle 17 is rotated in a first direction of rotation, the threaded screw 19 moves upward and thus raises the support 12 . When the direction of rotation of the threaded spindle 17 is reversed, the support is lowered. The threaded screw 19 is held in a connecting sleeve 20 , the upper edge of which forms a plate 9 on which a suspension spring 21 is supported with its upper end in FIG. 1. The electromechanical drive 1 and the suspension spring 21 are thus connected in series. With its lower end, the suspension spring 21 is seated on a housing 22 of a damper 23 , wherein the housing 22 of the damper can consist of several parts. The lower end 24 of the damper 23 is at least indirectly connected to a wheel axle, which is not shown in FIG. 1. The damper 23 has, as usual, a piston 25 which is guided sealingly on the inner surface of the housing 22 . As usual, the damper has the task of compensating for rapid vibrations of the wheel compared to the structure of the vehicle. The piston rod 26 of the damper 23 is connected to the connecting sleeve 20 , so that the vibrations of the suspension spring 21 relative to the connecting sleeve 20 are damped by the damper 23 . The motor housing 14 and the housing 22 of the damper 23 are provided with a first diaphragm 27 and a second diaphragm 28 which interlock in a telescopic manner.

In order to be able to regulate the movements of the structure and thus the support 12 , a sensor must be inserted which can measure such movements. Therefore on the ground of the connection sleeve 20, a first sensor 30 is inserted which is to measure the movement of the connecting sleeve 20 and thus the threaded screw 19 relative to the support 12 in a position. For this purpose, a pin 29 anchored relative to the support 12 , which transmits the movement of the support 12 relative to the connecting sleeve 20 . This movement can be measured by the first sensor 30 . Of course, within the scope of the invention, the first sensor or further sensors can be attached to other suitable locations on the device.

In the embodiment of Fig. 1, it is disadvantageous that the entire load of the body of the motor vehicle must be absorbed by the ball gear with the threaded screw 19 and the threaded spindle 17 . The loads on the transmission are therefore considerable and the resulting friction must be overcome by a corresponding expenditure of energy. In addition, the control works asymmetrically, since gravity acts as a support and counteracts the drive in the opposite direction. In Fig. 2, therefore, a relief spring 6 is inserted, which frees the ball gear from the load of gravity, so that only the acceleration of the body has to be transmitted in both directions via this gear. This results in a considerable saving in energy, since the relief spring 6 is connected in parallel with the transmission and is otherwise in series with the suspension spring 21 .

The embodiment according to FIG. 3 is largely the same as that of FIG. 1, only that the suspension spring 21 has been replaced by a gas spring 7 , which can also be used to regulate the level, that is to say to control the height of the support 12 relative to the road. The advantages that can be achieved by using a gas spring have already been described in detail above.

In Fig. 4, both the suspension spring 21 and the relief spring 6 have been replaced by a gas spring 7 and 21, respectively. The two gas springs can be controlled and fed by a common source, so that the suspension spring can be regulated to a certain extent. The suspension spring 7 can also remain reversed by being filled up once and remaining in this state later. The gas spring 7 can also serve to change the height of the support 12 to a greater extent, which results in a control of the level, that is, the distance between the support 12 and the road. The smaller vibrations of the support 12 can at least be compensated for by the second gas spring 8 . If both springs are not activated, the gas springs can be made in one piece via a split bellows. However, it is also possible to fill the upper bellows belonging to the relief spring 6 once with gas and to actuate the gas spring 7 by means of a corresponding gas source for regulating the level.

Claims (27)

1. Device for controlling movements of the body ( 12 ) of motor vehicles, the body ( 12 ) being supported indirectly or directly on at least one wheel axle via a series circuit comprising an actuator ( 1 ) and a suspension spring ( 21 ), characterized in that the actuator ( 1 ) is an electromechanical drive. 2. Device according to claim 1, characterized in that the actuator ( 1 ) is provided with an electric motor ( 15 ), the pole windings of which are fixed relative to the structure ( 12 ) and the rotor of which drives a threaded spindle ( 17 ), by means of which the rotation of the The distance between a threaded screw ( 19 ) and the body ( 12 ) can be changed and the support spring ( 21 ) is supported at least indirectly on the threaded screw ( 19 ) with its end facing away from the wheel axle. 3. Device according to claim 1 or 2, characterized in that the actuator (1) comprises a relief spring (6) is connected in parallel, which with its one end at least indirectly on the structure (12) end facing the bearing spring (6) and with their other end is supported at least indirectly on the structure ( 12 ). 4. Device according to one of the preceding claims, characterized in that the suspension spring ( 21 ) and / or the relief spring ( 6 ) is formed by a gas spring. 5. Device according to one of the preceding claims, characterized in that the gear screw ( 19 ) in connection with the spindle ( 17 ) forms a ball gear. 6. Device according to one of the preceding claims, characterized in that the relief spring ( 6 ) is selected in its rigidity such that it can bear the load exerted on it by the structure ( 12 ) without standing on the block. 7. Device according to one of the preceding claims, characterized in that a connecting sleeve ( 20 ) is provided on which both the support spring ( 21 ) and the relief spring ( 6 ) is supported and which also from the spindle ( 17 ) on the Threaded screw ( 19 ) absorbs the force exerted and transfers it to the suspension spring ( 21 ). 8. The device according to claim 7, characterized in that an extension of the connecting sleeve ( 20 ) is connected to a piston ( 25 ) which projects into a cylinder which is at least indirectly connected to the wheel axle and forms a damper ( 23 ) with the latter and at which the The support spring ( 21 ) is supported on the cylinder end facing away from the wheel axis. 9. Device according to one of the preceding claims, characterized in that a with the structure ( 12 ) facing end of the suspension spring ( 21 ) connected to the first sensor ( 30 ) is provided which detects the movement of the structure ( 12 ) end of the suspension spring ( 21 ) with respect to the vehicle axle, the sensor ( 30 ) preferably being attached to the extension of the connecting sleeve ( 19 ). 10. Device according to one of the preceding claims, characterized in that a second sensor ( 31 ) is provided, which records the movement of the body relative to the vehicle axis, the sensor (clearly) preferably at one with its first end with the body ( 12 ) connected rod ( 29 ) is attached, which protrudes into the cylinder and carries the sensor ( 31 ) there. 11. Suspension strut for motor vehicles, the suspension strut having a suspension spring, a damper and an actuator ( 1 ) with which the length of the suspension strut can be changed, characterized in that the actuator ( 1 ) has an electromechanical drive. 12. Strut for motor vehicles according to claim 11, characterized characterized in that the electric drive motor of the electromechanical drive directly on the shock absorber is attached. 13. Strut for motor vehicles according to claim 12, characterized characterized in that the electric drive motor of the Electromechanical drive in the strut structurally is integrated. 14. Strut for motor vehicles according to claim 11, 13, characterized in that the actuator ( 1 ) is arranged in series with the suspension spring. 15. A strut for motor vehicles according to claim 14, characterized in that the actuator ( 1 ) is connected to the upper, body-side end of the strut and the suspension spring to the lower, wheel-side end of the strut. 16. Strut for motor vehicles according to claim 15, characterized in that the suspension spring is supported via a spring plate ( 20 ) on the actuator ( 1 ), the distance of the spring plate from the upper end of the strut being variable with the aid of the actuator. 17. Strut for motor vehicles according to one of claims 11 to 16, characterized in that the damper is arranged parallel to the series connection of the suspension spring and actuator ( 1 ) between the upper and lower ends of the strut. 18. Strut for motor vehicles according to claim 17, characterized in that the axes of symmetry of the actuator ( 1 ) and damper coincide. 19. Strut for motor vehicles according to one of claims 11 to 18, characterized in that the actuator ( 1 ) is assigned a parallel relief spring ( 6 ). 20. Strut for motor vehicles according to claim 19, characterized in that the relief spring ( 6 ) is designed such that it largely keeps the static portion of the strut load from the actuator ( 1 ). 21. Shock absorber for motor vehicles according to one of claims 11 to 20, characterized in that the suspension spring ( 21 ) or the relief spring ( 6 ) or both springs are each formed by a gas spring, the gas quantities in the gas springs of the individual struts via corresponding connections and valves can also be changed while driving. 22. Strut for motor vehicles according to one of claims 11 to 21, characterized in that the actuator has a Ball screw drive, contains. 23. Strut for motor vehicles according to claim 22, characterized in that the threaded spindle of the ball screw drive is rotated by the electric drive motor and the spindle nut is fastened to the spring plate ( 20 ). 24. Strut for motor vehicles according to one of claims 11 to 23, characterized in that a first sensor ( 31 ) is provided, which detects the current length of the strut or its spring travel. 25. Strut for motor vehicles according to one of claims 11 to 24, characterized in that a second sensor ( 30 ) is provided which detects the travel of the actuator ( 1 ). 26. Strut for motor vehicles according to claim 25, characterized in that the second sensor ( 30 ) is formed by means which detect the rotation of the drive motor. 27. Strut for motor vehicles according to claim 24, 25 or 26, characterized in that at least one of the sensors ( 30 , 31 ) is formed by a sensor element which is received by the hollow damper shaft and determines its path signal based on the position of a permanent magnet, the Magnetic field protrudes through the wall of the damper shaft in its hollow center.