EP1711357A1

EP1711357A1 - Active roll stabilization system

Info

Publication number: EP1711357A1
Application number: EP05700520A
Authority: EP
Inventors: Marco Grethel; Manfred Homm; Michael Reuschel
Original assignee: LuK Lamellen und Kupplungsbau Beteiligungs KG; LuK Lamellen und Kupplungsbau GmbH
Current assignee: Schaeffler Buehl Verwaltungs GmbH; LuK Lamellen und Kupplungsbau GmbH
Priority date: 2004-01-28
Filing date: 2005-01-07
Publication date: 2006-10-18
Also published as: JP2007519558A; US7318594B2; DE112005000809A5; WO2005072999A1; US20070013151A1; DE102005000889A1

Abstract

The invention relates to an active roll stabilization system of a vehicle having an axle with at least two wheels, said axle being provided with a roll stabilizer that is actuated by means of a hydraulic device. Said hydraulic device is impinged upon via at least one pressure control valve with a preselected pressure level by means of a pressure supply device such as a pump. In order to reduce the costs for producing an active roll stabilization system of the aforementioned type, the pressure control valve is pilot-operated by a pressure control pilot valve.

Description

Wankstabilisierunqseinrichtunq

The invention relates to a device for active roll stabilization of a vehicle, with at least one axle having at least two wheels, which is provided with a transverse stabilizer which can be actuated with the aid of a hydraulic device which is operated by a pressure supply unit, such as a pump, via at least one pressure limiting valve preselected pressure level can be applied.

Such roll stabilization devices are also referred to as anti-roll systems or roll stabilization systems. In conventional anti-roll systems, directly controlled pressure limiting and directional control valves are used.

The object of the invention is to provide a device for active roll stabilization of a vehicle, with at least one axle having at least two wheels, which is provided with a transverse stabilizer which can be actuated by means of a hydraulic device which is actuated by a pressure supply unit, such as a pump, via at least one Pressure relief valve can be acted upon with a preselected pressure level to create, which is inexpensive to manufacture.

The object is in a device for active roll stabilization of a vehicle, with at least one axle having at least two wheels, which is provided with a transverse stabilizer, which can be actuated by means of a hydraulic device, which is operated by a pressure supply unit, such as a pump, via at least one pressure relief valve a preselected pressure level can be acted upon, in that the at least one pressure relief valve is pilot operated by a pressure relief pilot valve. In the context of the present invention, it was found that the magnetic coils used in conventional anti-roll systems for direct actuation of the pressure relief valves have a not inconsiderable cost. cause ten percent. In contrast, the present invention provides the advantage that inexpensive pilot valves available on the market can be used.

The object specified above is for a device for active roll stabilization of a vehicle, with at least two axles having at least two wheels, each of which is provided with a transverse stabilizer, the transverse stabilizers being operable with the aid of hydraulic devices which are actuated by a pressure supply unit, such as a pump, Different pressure levels can be applied via pressure limiting valves, in that the pressure limiting valves assigned to the hydraulic devices are pilot-controlled by at least two pressure limiting pilot valves connected in series. The series connection of the pressure limiting pilot valves provides the advantage that an additional, additional pilot-related inlet orifice can be omitted.

A preferred exemplary embodiment of the roll stabilization device is characterized in that a direction changeover valve, for example a 7/2-way valve, which is used for the direction-dependent changeover of the hydraulic devices, is piloted by a direction changeover pilot valve. This can further reduce manufacturing costs. Another preferred exemplary embodiment of the roll stabilization device is characterized in that a fail-safe valve, which is pilot-controlled by a fail-safe pilot valve, is connected between the direction changeover valve and one of the hydraulic devices. This can further reduce manufacturing costs.

Another preferred exemplary embodiment of the roll stabilization device is characterized in that a direction changeover valve, for example a 7/2-way valve, which is used for the direction-dependent changeover of the hydraulic devices, and a fail-safe valve which is connected between the direction changeover valve and one of the hydraulic devices , are piloted by a single switching pilot valve. The advantage here is, on the one hand, that there is no additional pilot control circuit due leakage point and secondly in the absence of an additional pilot valve.

A further preferred exemplary embodiment of the roll stabilization device is characterized in that the switching pilot valve has three switching positions, wherein in the first state of the switching pilot valve neither the direction changeover valve nor the fail-safe valve are switched, wherein in the second state of the switching pilot valve only the fail-safe valve is switched and in the third state of the switching pilot valve both the fail-safe valve and the direction changeover valve are switched. The direction changeover valve and the fail-safe valve are preferably spring-biased directional valves with two switch positions. In the first state, the switching pilot valve can be de-energized. Then both the direction change-over valve and the fail-safe valve are in their starting position, in which they are held, for example, by a prestressed spring, as long as a magnet used to actuate the directional control valves is de-energized. In the second state, the switching pilot valve is energized so that the pilot pressure overcomes the spring bias of the fail-safe valve and switches the fail-safe valve from its initial position to its second position. With the medium current supply, the resulting pressure force on the direction changeover valve is not yet sufficient to overcome its greater pretension, so that the direction changeover valve remains in its initial position. With a higher current supply to the switching pilot valve and thus the higher pressure, the direction changeover valve is also switched from its initial position to its second position. The fail-safe valve remains in its second position.

Another preferred embodiment of the roll stabilization device is by a pressure reducing valve, which the pilot pressure level of z. B. sets 5 bar, marked. This total pilot pressure valve is operated in parallel to the pressure relief valves for the actuators. Another preferred exemplary embodiment of the roll stabilization device is characterized in that the total pilot pressure reducing valve is acted upon by the pressure from a tank from which the pressure supply unit is supplied. The targeted return of the tank pressure into the spring chamber of the overall pilot pressure reducing valve ensures that the total pilot pressure is raised by the tank pressure level and a control differential pressure of, for example, 5 bar is available. This eliminates the influence of the tank pressure level on the pilot circuit.

A further preferred exemplary embodiment of the roll stabilization device is characterized in that the pressure limiting valves and / or the direction changeover valve and / or the fail-safe valve are / are pressurized with the pressure from a tank from which the pressure supply unit is supplied. Through the targeted return of the tank pressure into the spring chamber of the pressure relief valves, the direction changeover valve and / or the fail-safe valve, the overall pilot pressure is raised by the tank pressure level and a control differential pressure of 5 bar, for example, is available.

Another preferred exemplary embodiment of the roll stabilization device is characterized in that all valves comprise valve pistons which are guided in a cast valve block, in particular made of die-cast aluminum, in which channels for supplying and / or discharging hydraulic medium are cast. Conventional valves for the chassis area are designed in the so-called plug-in design. The valve piston is guided in a valve sleeve which is firmly connected to a magnet. The valve sleeve is in turn in a valve block, against which it is sealed with the help of O-rings. By guiding the valve piston directly in the valve block, both the valve sleeve and the O-rings can be omitted.

A further preferred embodiment of the Wankstabilisierungseinrichtu ^{"" x} characterized in that several valves through molded channels mite.T. ^ n- who are communicating. This has the advantage that time-consuming reworking of the valve block can be omitted.

A further preferred exemplary embodiment of the roll stabilization device is characterized in that valve slide elements, control elements, sensor elements, hydraulic elements and / or electronic elements of several valves are combined in one unit and are shielded from the environment by a protective cover, in particular a protective trough. The protective cover has the advantage that there is no need for complex and cost-intensive individual protection of the magnets and sensors. The protective cover seals off the control elements from the outside and at the same time ensures that no hydraulic medium gets into the environment.

Another preferred exemplary embodiment of the roll stabilization device is characterized in that the individual control elements, sensor elements, hydraulic elements and / or electronic elements are electrically connected directly to one another. The elimination of a cable harness with its large number of plug connections not only reduces manufacturing costs, but also significantly increases system security. Thanks to the direct contact of magnets, sensors and the connector with the electronics, internal control wiring is not necessary. The sensors, for example pressure and displacement sensors, do not require independent housings, amplifiers and evaluation units.

Further advantages, features and details of the invention result from the following description, in which various exemplary embodiments are described in detail with reference to the drawing. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination. Show it:

Figure 1 is a hydraulic circuit diagram of a conventional roll stabilization device; FIG. 2 shows a hydraulic circuit diagram of a roll stabilization device according to the invention with pilot-controlled valves;

FIG. 3 shows a hydraulic circuit diagram of a roll stabilization device according to the invention with two pressure limiting pilot valves connected in series;

FIG. 4 shows a hydraulic circuit diagram of a roll stabilization device according to the invention with targeted tank pressure feedback;

5 shows a longitudinal section through a valve block with a valve piston guided therein, and FIG. 6 shows a schematic representation of a roll stabilization control device according to the invention in section.

The actual state of a standard system is shown in FIG. Pressure supply unit is a suction-throttled radial piston pump 21, which provides two different pressure levels via a cascade connection by means of two proportional pressure relief valves 22 and 28, which are connected as pressure differential valves. The pressure levels are monitored by pressure sensors 23 and 27. These pressure ranges are designated 35 for the right side and 34 for the left side for a swivel motor on the stabilizer on the front axle, and 33 and 32 for a swivel motor on the stabilizer on the rear axle. The pressure on the rear axle must always be lower than the pressure on the front axle. These two pressure levels are switched by means of a 7/2-way valve 24, which is also referred to as a direction changeover valve, when cornering on the right or left, so that either the pressure in the swivel motors on the right or on the left side of the vehicle increases or lowers. The operation of the direction changeover valve 24 is monitored with the aid of a switch position detection sensor 26. In addition, a fail-safe valve 25 is arranged in the front axle hydraulic train, which serves to block the swivel motor 37 of the front axle in the event of a valve jamming or in the event of a power failure and to depressurize the swivel motor 36 of the rear axle. In addition, two suction valves 29 and 30 are attached, each of the pressure range 35 and 34 of the swivel motor 37 on the Can connect the front axle to the tank line and the tank 31 in such a way that the swing motor 37 can be throttled freely via the leakage points in the swing motor even by sucking in the volume flow without cavitation problems.

The proportional pressure relief valves 22 and 28 and the 7/2 and 3/2-way valves 24 and 25 are directly controlled valves. A not inconsiderable share of the costs is caused by the solenoids used for the control. To ensure the necessary actuating forces for the valves, quite large and expensive solenoids are used. Therefore, in the context of the present invention, considerations were made to replace the direct control of the valves by a pilot control. The big advantage is the availability of inexpensive pilot valves.

In the embodiment shown in Figure 2, the direct magnets were replaced by pilot valves 42. In addition, the pump 21 was followed by a pressure reducing valve 41 to provide the total pilot pressure. The hydraulic circuit diagrams shown in Figures 1 to 4 are similar. The same reference numerals have been used to designate the same parts. To avoid repetition, reference is made to the previous description of FIG. 1. Only the differences between the individual versions are discussed below.

In FIG. 2, the pressure relief valve 22 is preceded by a pressure relief pilot valve 44 and an inlet orifice 45. A pressure relief pilot valve 48 and an inlet orifice 49 are connected upstream of the pressure relief valve 28. The direction switch valve 24 is connected upstream of a direction switch pilot 51. A fail-safe pilot valve 52 is connected upstream of the fail-safe valve 25. In addition to the availability of inexpensive pilot control valves, the exemplary embodiment shown in FIG. 2 has the advantage that higher actuating forces can possibly act on the main valves, which increases safety during operation. In addition, smaller solenoids can be used to control the pilot valves, which, due to their lower power consumption, do not put as much strain on the vehicle electrical system as the conventional used direct magnets. However, an increased system leakage was found in tests carried out within the scope of the present invention on the roll stabilization device shown in FIG. 2, which has a disadvantageous effect on the overall efficiency and / or the dynamics of the system. In addition, the tank pressure, which can be up to 15 bar at low temperatures, can significantly influence the function of the pilot control circuit. These problems have been eliminated by the exemplary embodiments shown in FIGS. 3 and 4.

3 shows in an ellipse 42 that the pressure relief pilot valves 44 and 48 are connected in series, in contrast to the exemplary embodiment shown in FIG. This has the advantage that a parallel oil flow through the inlet orifice 49 (FIG. 2), which represents a “leakage point” caused by the pilot circuit, can be eliminated in the pilot circuit. A single pilot valve 61 is arranged in an ellipse 60, which switches off the two pilot valves 51 and 52 Figure 2 replaced.

The pilot valve 61 has three discrete switching positions. In the de-energized state, the two directional control valves 24 and 25 are not switched. With a medium current supply to the switching pilot valve 61, the pilot pressure overcomes the bias of a spring 65 on the fail-safe valve 25, so that the fail-safe valve 25 switches to its second position (not shown in FIG. 3). With this medium current supply, the resulting pressure force on the direction changeover valve 24 is not yet sufficient to overcome the greater preload of a spring 66. Accordingly, the direction changeover valve 24 remains unswitched, that is to say in the position shown in FIG. 3. When the switching pilot valve 61 is energized, the biasing force of the spring 66 is overcome by the higher pilot pressure, and the direction switching valve 24 switches to its second switching position (not shown in FIG. 3). The fail-safe valve 25 remains in its second position.

In Figure 3 it is also indicated by arrows 63 and dashed lines that the tank pressure is fed back into the spring spaces of the pressure reducing valve 41 and the directional control valves 24, 25. The return of the tank pressure in the spring chamber of the pressure reducing Valve 41 ensures that the total pilot pressure is always raised by the pressure level of the tank pressure and thus a control differential pressure of, for example, 5 bar is available. The same applies to the two directional control valves 24, 25.

In FIG. 4, arrows 67 and dashed lines indicate that the tank pressure is not only attributed to the pressure reducing valve 41 and the directional control valves 24, 25, but also to the pressure limiting valves 22, 28.

An aluminum die-cast housing 70 is shown in section in FIG. A blind hole 72 is recessed in the die-cast aluminum housing 70, in which a valve piston 73 is accommodated so that it can move back and forth. The blind hole 72 is closed by means of a plug 74 which is held in the blind hole 72 by a holding plate 75. On the side of the holding plate 75 facing away from the valve piston 73, a receiving space 76 is provided for a magnet (not shown). The holding plate 75 and / or the plug 74 can also be formed by the magnet. The plug 74 and the holding plate 75 can also be integrated in the magnet. The valve piston 73 is pressed by the prestressing force of a helical compression spring 77 against a stop surface 78 which forms the bottom of the blind hole 72.

In the die-cast aluminum housing 70, which is also referred to as the valve housing, four lamellae 81, 82, 83, 84 are recessed in the region of the valve piston 73, which run transverse to the longitudinal axis of the valve piston 73. The lamella 81 is used for leakage feedback. The lamella 82 forms a connecting channel to a pump (21 in FIGS. 1 to 4). The lamella 83 forms an outflow channel, for example, to a pressure limiting valve (22, 28 in FIGS. 1 to 4). The lamella 84 represents, for example, a connection channel to a further pilot valve.

The valve shown in FIG. 5 can be, for example, a pressure limiting pilot valve, as shown in FIGS. 2 to 4 and designated 22 and 28. The valve piston 73 is acted upon by the pilot pressure via the lamella 81. In the position of the valve piston 73 shown in FIG Hydraulic medium charged with the pilot pressure via the lamella 82 and a notch 86, which is formed on the valve piston 73, into the outflow lamella 83, which is connected to one of the pressure limiting valves (22, 28 in FIGS. 2 to 4). If the pilot pressure in the lamella 81 overcomes the biasing force of the spring 77, or if the valve piston 73 is moved away from the stop surface 78 with the aid of a magnet, then the connection between the lamellae 82 and 83 is interrupted. The so-called labyrinth solution of the flow channels shown in FIG. 5 provides the advantage that the valve piston 73 runs directly in the valve block 70. Several valves are connected to each other by cast channels.

In Figure 6, a vehicle interface is designated 90. Electronic elements 91 of a roll stabilization control device according to the invention are attached directly to the vehicle interface. Sensor elements 92 are attached directly to the electronic elements 91. A connector plug 93 is connected directly to the electronic elements 91. Channels and connections, in particular hydraulic connections 95, for the valves are accommodated in a first control plate 94, which is formed by a die-cast aluminum housing part in the labyrinth construction of the flow channels. A second control plate 99 is separated from the first control plate 94 by an intermediate plate 98. Sliders and magnets 100 of the valves are accommodated in the second control plate 99. A protective plate 104, which is also referred to as a protective trough, isolates the electronic elements, sensor elements and the control plates from the outside. This has the advantage that the respective components do not have to be encapsulated individually. The protective trough 104 takes over the partitioning of the control elements to the outside and at the same time ensures that no oil gets into the environment. The direct contact between the individual elements provides the advantage that a complex wiring harness with a large number of plug connections can be omitted. This not only reduces costs, but also significantly increases system security. LIST OF REFERENCES

21. Suction-throttled radial piston pump 22. Proportional pressure relief valve 23. Pressure sensor 24.7 / 2-way valve 25. Fail-safe valve 26. Switch position detection sensor 27. Pressure sensor

28. Proportional pressure relief valve

29. Suction valve

30. Suction valve

31. Tank 32. Pressure area left side HA - swing motor

33. Printing area right side HA - swing motor

34. Printing area left side VA - swing motor

35. Printing area right side VA - swing motor

36. Swing motor rear axle 37. Swing motor front axle

38.- 39.- 40.-

41. Pressure reducing valve for total pilot pressure 42. Pilot valve 43.-

44. pilot valve for 22

45. inlet panel for 44 46.- 47.-

48. pilot valve for 28 49. Inlet cover for 48 50.-

51. Pilot valve for 24

52. pilot valve for 25 53.-

54.- 55.- 56.- 57.- 58.- 59.-

60th ellipse

61. a single pilot valve (instead of 51 and 52) for 24 and 25 62.- 63. tank pressure feedback for 41, 24, 25

64. -

65th spring

66th pen

67. Tank pressure feedback for 22, 28, 24, 25, 41 68.-

69.-

70. Die-cast aluminum housing

71-

72. Blind hole 73. Valve piston

74. Plug

75. Retaining plate

76th place for magnet (can also replace 74, 75)

77. Coil compression spring 78. Stop surface

79.- 80.-

81. Lamella => pilot pressure feedback

82. Lamella => connecting channel to the pump

83rd lamella => outflow channel to pressure relief valve 84th lamella => connecting channel to further pilot valve 85.- 86. notch 87.- 88.- 89.-

90th vehicle interface

91. Electronics 92. Sensor technology

93. Connector with direct contact 94. first control plate

95. Hydraulic connections

96. -

97.-

98. intermediate plate 99. second control plate

100th magnet

101. -

102. -

103. - 104. mudguard

Claims

claims

1. Device for active roll stabilization of a vehicle, with at least one axle having at least two wheels, which is provided with a transverse stabilizer which can be actuated with the aid of a hydraulic device (36, 37) which is operated by a pressure supply unit (21), such as a pump, A preselected pressure level (32, 33; 34, 35) can be acted upon by at least one pressure limiting valve (22, 28), characterized in that the pressure limiting valve (22, 28) is piloted by a pressure limiting pilot valve (44, 48).

2. Device for active roll stabilization of a vehicle, with at least two axles having at least two wheels, each of which is provided with a transverse stabilizer, the transverse stabilizers being operable with the aid of hydraulic devices (36, 37) operated by a pressure supply unit (21), such as a pump via which pressure relief valves (22, 28) can be acted upon with different pressure levels (32, 33; 34, 35), characterized in that the pressure relief valves (22, 28) assigned to the hydraulic devices (36, 37) are connected in series by at least two Pressure relief pilot valves (44,48) are pilot operated.

3. Roll stabilization device according to one of the preceding claims, characterized in that a direction switch valve (24), for example a 7/2-way valve, which is used for direction-dependent switching of the hydraulic devices (36, 37), is pilot-controlled by a direction switch pilot valve (51) ,

4. Roll stabilization device according to claim 3, characterized in that between the direction switching valve (24) and one of the hydraulic devices (37) a fail-safe valve (25) is connected, which is pilot-controlled by a fail-safe pilot valve (52).

5. Roll stabilization device according to claim 2, characterized in that a direction change-over valve (24), for example a 7/2-way valve, which serves for direction-dependent switching of the hydraulic devices (36, 37), and a fail-safe valve (25) is connected between the direction changeover valve (24) and one of the hydraulic devices (37), are piloted by a single switching pilot valve (61).

6. roll stabilization device according to claim 5, characterized in that the switching pilot valve (61) has three switching positions, wherein in the first state of the switching pilot valve (61) neither the direction switching valve (24) nor the fail-safe valve (25) are switched, wherein in only the fail-safe valve (25) is switched in the second state of the switching pilot valve (61), with both the fail-safe valve (25) and the direction change-over valve (24) being switched in the third state of the switching pilot valve (61).

7. Roll stabilization device according to one of the preceding claims, characterized by an overall pilot pressure reducing valve (41) which is connected between the pressure supply unit (21), the pressure limiting pilot valve (44) and in parallel with the pressure limiting valve (22).

8. Roll stabilization device according to claim 7, characterized in that the overall pilot pressure reducing valve (41) is pressurized with the pressure from a tank (31) from which the pressure supply unit (21) is supplied.

9. Roll stabilization device according to one of claims 2 to 8, characterized in that the pressure limiting valves (22, 28) and / or the direction changeover valve (24) and / or the fail-safe valve (25) with the pressure from a tank (31 ) are / is supplied from which the pressure supply unit (21) is supplied.

10. Roll stabilization device according to one of the preceding claims, characterized in that all valve pistons (73) comprise that in a cast Valve block (70), in particular made of die-cast aluminum, are guided, in which channels (81, 82, 83) for supplying and / or discharging hydraulic medium are cast.

11. Roll stabilization device according to claim 10, characterized in that different valves are connected to one another by cast channels (83, 84).

12. Roll stabilization device according to one of the preceding claims, characterized in that slide elements, control elements, sensor elements, hydraulic elements and / or electronic elements of a plurality of valves are combined in one unit.

13. Roll stabilization device according to one of the preceding claims, characterized in that the unit is shielded from the environment by a protective cover (104), in particular a protective trough.

14. Roll stabilization device according to claim 12 or 13, characterized in that the individual control elements, sensor elements, hydraulic elements and / or electronic elements are electrically connected directly to one another.