Spring-Damper System

Abstract

A spring-damper system for a wheel suspension of a motor vehicle comprise a support spring of a spring constant k.sub.T and a damper acting in parallel to the support spring. A spring element is arranged in series with the support spring and can be controlled by means of a controller in such a way that a total spring constant k.sub.G of the spring-damper system can be varied.

Claims

1.-15. (canceled)

16. A spring-damper system for a wheel suspension of a motor vehicle, comprising a load-bearing spring with a spring constant and a damper acting parallel to the load-bearing spring, wherein a spring element is included which acts in series with the load-bearing spring and is controllable by a control device in such a manner that an overall spring constant of the spring-damper system can be varied.

17. The spring-damper system according to claim 16, wherein the spring element comprises a cartridge, a piston rod for coupling to the load-bearing spring, and a spring unit.

18. The spring-damper system according to claim 17, wherein the piston rod extends into a cartridge interior space of the cartridge, and a main piston having a bypass for a hydraulic fluid is arranged at an end of the piston rod arranged in the cartridge interior space, wherein a valve which is controllable by the control device is provided for controlling the bypass.

19. The spring-damper system according to claim 17, wherein the spring unit has a spring cartridge, the spring cartridge interior space of which is hydraulically connected directly or indirectly to the cartridge.

20. The spring-damper system according to claim 19, wherein the spring unit comprises a spring with a spring constant, a separating piston, and a separating piston stop, wherein the separating piston divides the spring cartridge interior space into a spring chamber and a third working chamber, wherein the spring is arranged in the spring chamber and presses the separating piston in the spring cartridge in the direction of the separating piston stop.

21. The spring-damper system according to claim 18, wherein the main piston divides the cartridge interior space into a first and a second working chamber, which is in each case filled with the hydraulic fluid, and the piston rod extends through the first working chamber.

22. The spring-damper system according to claim 20, wherein the spring unit is integrated in the cartridge in such a manner that the third working chamber and the second working chamber merge directly into each other and form a common working chamber.

23. The spring-damper system according to claim 20, wherein the third working chamber and the second working chamber are connected to each other by means of a hydraulic line.

24. The spring-damper system according to claim 17, wherein the cartridge comprises a displaceable base which is mounted movably in the cartridge.

25. The spring-damper system according to claim 21, wherein the displaceable base together with the main piston forms the first working chamber.

26. The spring-damper system according to claim 20, wherein the spring is a spiral spring and/or a gas compression spring filled with nitrogen.

27. The spring-damper system according to claim 18, wherein the controllable valve is controllable electrically, mechanically, hydraulically or pneumatically.

28. The spring-damper system according to claim 16, wherein an input means for controlling the spring element is operatively connected to the control device.

29. The spring-damper system according to claim 18, wherein a temperature sensor for determining a hydraulic fluid temperature is provided, and wherein data for controlling the valve depending on the hydraulic fluid temperature are stored in the control device.

30. The spring-damper system according to claim 18, wherein the valve comprises a coil with an internal resistor, and further data for controlling the valve depending on the hydraulic fluid temperature are stored in the control device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 shows a spring-damper system for a wheel suspension of a motor vehicle;

[0028] FIG. 2 shows an alternative spring-damper system for a wheel suspension of a motor vehicle.

[0029] The figures are schematic by way of example. The same reference numbers in the figures indicate identical functional and/or structural features.

DETAILED DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 illustrates a spring-damper system 10 for a wheel suspension of a motor vehicle, comprising a load-bearing spring 20 (not shown) with a spring constant k.sub.T and a damper 30 (not shown) acting parallel to the load-bearing spring 20. A spring element 1 is included here which acts in series with the load-bearing spring 20 and is controllable via a control device 12 in such a manner that an overall spring constant k.sub.G of the spring-damper system 10 can be varied. The control device 12 may comprise known hardware and/or software components, including a controller, processor, CPU, or microprocessor configured to execute software and/or firmware stored in a memory, such as RAM or ROM.

[0031] The spring element 1 comprises a cartridge 2, a piston rod 3 for coupling to the load-bearing spring 20, and a spring unit 4. The piston rod 3 extends into a cartridge interior space 21 of the cartridge 2, and a main piston 5 having a bypass 6 for a hydraulic fluid 9 is arranged at an end of the piston rod 3 arranged in the cartridge interior space 21. In addition, a valve 11 which is controllable via the control device 12 is provided for controlling the bypass 6. The controllable valve 11 is controllable electrically, mechanically, hydraulically or pneumatically.

[0032] Furthermore, the spring unit 4 has a spring cartridge 41, the spring cartridge interior space 42 of which is hydraulically connected directly to the cartridge 2, a spring 43 with a spring constant k.sub.F, a separating piston 44, and a separating piston stop 45. The separating piston 44 divides the spring cartridge interior space 42 into a spring chamber 46 and a third working chamber 81 here. Furthermore, the spring 43 is arranged in the spring chamber 46 and presses the separating piston 44 in the spring cartridge 41 in the direction of the separating piston stop 45. The spring 43 is a spiral spring and/or a gas compression spring filled with nitrogen.

[0033] Furthermore, the main piston 5 divides the cartridge interior space 21 into a first and a second working chamber 7, 8, which is in each case filled with the hydraulic fluid 9, and the piston rod 3 extends through the first working chamber 7. The spring unit 4 is integrated in the cartridge 2 in such a manner that the third working chamber 81 and the second working chamber 8 merge directly into each other and form a common working chamber.

[0034] In addition, the cartridge 2 comprises a displaceable base 22 which is mounted movably in the cartridge 2. The displaceable base 22 together with the main piston 5 forms the first working chamber 7. In addition, an input means 15 is provided which is connected for controlling the spring element 1 via the control device 12. The input means may comprise electronic and/or mechanical input means, such as a touch screen, button, switch, dial or knob.

[0035] In addition, a temperature sensor 14 for determining the hydraulic fluid temperature is provided, and data 16 for controlling the valve 11 depending on the hydraulic fluid temperature are stored in the control device 12. The data 16 may be stored in a memory, such as the associated with the control device 12.

[0036] FIG. 2 shows an alternative spring-damper system 10 for a wheel suspension of a motor vehicle. Since the features of this spring-damper system 10 substantially correspond to the features of the embodiment illustrated in FIG. 1, only different features will be discussed below.

[0037] The spring-damper system 10 comprises a spring unit 4 with a spring cartridge 41, the spring cartridge interior space 42 of which is hydraulically connected indirectly to the cartridge 2. The third working chamber 81 and the second working chamber 8 of the spring-damper system 10 are connected to each other here via a hydraulic line 13. Furthermore, the valve 11 comprises a coil with an internal resistor, and further data 17 for controlling the valve 11 depending on the hydraulic fluid temperature are stored in the control device 12. The data 17 may be stored in a memory, such as the associated with the control device 12.

[0038] The disclosure is not limited in terms of its design to the preferred exemplary embodiments described above. Rather, numerous variants are conceivable which make use of the presented solution even in fundamentally different embodiments.