WO2004085178A1

WO2004085178A1 - Anti-roll system

Info

Publication number: WO2004085178A1
Application number: PCT/DE2004/000580
Authority: WO
Inventors: Ivo Agner
Original assignee: Luk Fahrzeug-Hydraulik Gmbh & Co. Kg
Priority date: 2003-03-26
Filing date: 2004-03-20
Publication date: 2004-10-07
Also published as: DE112004000076B4; DE112004000076D2

Abstract

The invention relates to an anti-roll system or roll-stabilizing system, comprising a stabilizer and an actuator (76, 78), such as a swivel motor or cylinder, on the front axle and on the rear axle of a motor vehicle, and comprising a control valve (5). The anti-roll system serves to influence the stabilizer and a common supply of the actuators (76, 78) by a pump (1).

Description

Anti-roll Svstem

The invention relates to an anti-roll system or roll stabilization system, each with a stabilizer and an actuator, such as. B. swivel motor or cylinder, on the front axle and on the rear axle of a motor vehicle to influence the stabilizer and a common supply of the actuators by a pump and with a control valve.

Anti-roll systems of this type are known. They serve the suspension of a motor vehicle with one-sided compression and rebound of the wheels assigned to an axle, for. B. when cornering, harden and thus avoid a torsional vibration of the vehicle about its longitudinal axis. Such vibrations are also referred to as rolling or swaying. The known anti-roll systems have a hydraulic device, for example a swivel motor, which interacts with two stabilizer sections in such a way that mutual rotation is brought about. The torques generated thereby counteract a deflection of a wheel connected to the anti-roll bar. In the known hydraulic systems, however, it is not possible to set a higher pressure on the swivel motor of the rear axle than on the front axle.

If higher torsional torques are to be set on the rear axle than on the front axle in these systems, this can only be achieved by using larger actuator areas on the rear swivel motor or by adjusting the stabilizer geometry. The former is at the expense of dynamism, the second solution often leads to unloved compromises in the vehicle package.

The higher twisting torques are desirable, however, because due to a stiffer stabilizer on the rear axle compared to the front axle, driving behavior can be shifted in the direction of oversteering, which ensures greater agility, especially at lower driving speeds. It's also easier to find a balanced, to generate constant driving behavior with different vehicle load conditions.

It is therefore an object of the invention to realize these properties without the disadvantages mentioned above.

The task is carried out by an anti-roll system or a roll stabilization system, each with a stabilizer and actuator, such as. B. swivel motor or cylinder, on the front axle and on the rear axle of a motor vehicle to influence the stabilizer and with a common supply of the actuators by a pump and with a control valve in that the control valve divides the pump volume flow into a front axle volume flow and a rear axle volume flow and (additionally) regulates the pressure on the front axle actuator. An anti-roll system is preferred in which the control valve on the front axle can also allow a lower pressure than on the rear axle actuator. Furthermore, an anti-roll system is preferred in which the control valve has a pressure reducing function for the front axle actuator, in particular through an additional bypass tank drain for the front axle volume flow.

An anti-roll system according to the invention is characterized in that a common changeover valve for the front axle actuator and for the rear axle actuator for switching the volume flows during right-hand or left-hand cornering of the vehicle is arranged downstream of the control valve. An anti-roll system is also preferred which has a pressure control valve downstream of the area of the switchover valve for the rear axle actuator, which can be connected to the higher pressure area of the rear axle actuator via one or two non-return valves.

An anti-roll system according to the invention is characterized in that the pressure control valve for the rear axle pressure is arranged in the area of the rear axle actuator. Furthermore, a pressure sensor for the rear axle pressure is arranged in the area of the rear axle actuator. An anti-roll system is also preferred, in which connections such. B. expansion hoses, the area of the rear axle actuator with the Area of the front axle actuator is connected. Furthermore, an anti-roll system is preferred, in which the control valve and the changeover valve are arranged in the region of the front axle actuator.

An anti-roll system according to the invention is characterized in that the pressure control valve for the rear axle pressure can regulate the pressure at the rear axle actuator independently of the pressure level at the front axle actuator. An anti-roll system is also preferred, in which a fail-safe valve for the front axle actuator is arranged downstream behind the area of the switchover valve for the front axle actuator. Furthermore, an anti-roll system is preferred, in which suction valves for the front axle actuator are arranged downstream behind the fail-safe valve.

An anti-roll system according to the invention is characterized in that the control valve, for example in the event of a lack of oil, favors the front axle actuator over the rear axle actuator for supplying oil. Another anti-roll system is characterized by the fact that the control valve can be pilot-controlled. The pressure control valve for the rear axle actuator can also be pilot-controlled.

The invention will now be described with reference to the figures.

Figure 1 shows a control valve according to the invention.

Figure 2 shows a hydraulic circuit diagram of a subsystem.

Figure 3 shows a hydraulic diagram of the overall system.

FIG. 1 shows a control valve according to the invention and part of the hydraulic circuit diagram of the anti-roll system. A hydraulic pump 1, which is preferably a suction-controlled piston pump, feeds a control valve 5 via a connection 3 with the volume flow required by the anti-roll system. The valve 5 has a valve piston 7, which has three piston collars 9, 11 and 13 and is arranged displaceably in a valve bore 15. The valve bore 15 also has a connection 17 to the rear axle actuator, a connection 19 to the front axle actuator and a connection 21 to an oil reservoir 23. The connection 19 to the front axle actuator leads to a Connection 25, through which the entire volume flow flows to the front axle actuator, and into a pilot control connection 27 to the piston surface 31 of the collar 9 of the valve piston 7. A damping resistor 29 is arranged in the pilot control connection 27. On the pump side, a control oil line 32 branches off from the connection 3, which leads control oil to the piston surface 33 of the piston collar 13 of the valve piston 7. A resistor 35 is also arranged in the control line 32 and serves both as a damping resistor and as a resistor for generating a pressure drop. A force of a spring 37 also acts on the surface of the piston 33. Furthermore, a pilot valve 39 is arranged at this end of the valve bore 15, which can close the spring chamber in a pressure-tight manner by means of a seat valve 41. The seat valve 41 can be actuated electrically by an electromagnet 43. If the control pressure in the spring chamber, which acts on the piston surface 33 and the seat valve 41, exceeds the magnetic force on the seat valve 41, the seat valve 41 will open and a control oil flow will flow into the oil reservoir 45. As a result, the control pressure on the surface 33 of the valve piston 7 cannot increase any further. By varying the magnetic force, the control pressure in the spring chamber can be regulated to different levels. In the position of the valve piston 7 shown here, the volume flow from the pump 1 can reach the connection 19 and thus to the front axle actuator without throttling. A pressure is established in the connection 19 and in the line 25 to the front axle actuator in accordance with the forces acting on the front axle actuator, which pressure acts on the piston surface 31 via the pilot control connection 27 and the resistor 29. If this pressure on the front axle actuator exceeds the control pressure on the piston surface 33 in the spring chamber, which is predetermined by the pilot valve 39, and the force of the spring 37, the valve piston 7 is shifted to the right, and the control edge 47 of the piston collar 1 1 opens a connection to the rear axle actuator. As a result, an oil flow throttled via the control edge 47 will flow to the rear axle actuator to the extent that the pressure at the front axle actuator can no longer increase. The control valve 5 therefore always sets a pressure for the front axle actuator, which corresponds to the balance of forces on the left piston surface 31 and on the right piston surface 33, which is determined by the pilot valve 39. If the pressure on the rear axle is now to be higher than the pressure on the front axle, a control edge change to the control edge 49 takes place on the piston collar 11 of the valve piston 7. The piston 7 thus continues to move to the right and thus throttles the inlet to the front axle actuator via the control edge 49. The volume flow to the rear axle actuator via the control edge 47 is thus guided through the valve practically unthrottled. If the inflow throttling to the front axle actuator via the control edge 49 is not sufficient to maintain the desired lower pressure at the front axle actuator, an additional control edge 51 on the piston collar 13 is opened when the valve piston 7 moves further to the right, which controls a bypass oil flow to the tank 23 allows and thus can lower the pressure at the front axle actuator by drain. This means that a higher pressure can now be set on the rear axle actuator than on the front axle actuator.

In Figure 2, the control valve 5 from Figure 1 and a pressure control valve 55 for the rear axle actuator are symbolically shown in a circuit diagram. The same reference symbols are used for the control valve 5 from FIG. 1 for the same structures and functions, so that a repeated explanation is unnecessary to avoid repetition. The volume flow to the rear axle actuator is passed behind the control valve 5 for the front axle actuator via a connection 53 to the pressure control valve 55 for the rear axle actuator. The pressure at the rear axle actuator, which is established in line 59, is passed via a pilot control connection 61 to a piston surface 63 of the pressure control valve 55. A spring force of a spring 67 and in turn a control pressure act on the opposite surface 65 of the pressure control valve 55, which can be set by a pilot valve 57 analogously to the pilot control of the control valve 5 for the front axle. The pressure at the rear axle actuator can thus be regulated via this pressure control valve 55 independently of the pressure at the front axle actuator. The symbolically represented tank connections 23 and 45 from FIG. 1 are implemented in practice by a common oil tank 23, 45 for the overall system.

Figure 3 shows the circuit diagram of the entire anti-roll system. Parts and functions which have already been explained in FIG. 1 and FIG. 2 are provided with the same reference symbols and are not explained again here. It can be seen in FIG. 3 that downstream of the control valve 5, which divides the pump volume flow of the pump 1 into a volume flow to the front axle actuator 76 via the connection 25 and into a volume flow to the rear axle actuator 78 via the connection 53, a changeover valve 70 is shown, which is mechanically connected to a changeover area 72 for the front axle actuator 76 and a switchover area 74 for the rear axle actuator 78. This changeover valve 70 serves to simultaneously conduct the pressurized volume flow both into the right chamber of the front axle actuator 76 and into the right chamber of the rear axle actuator 78 and to connect the left chamber of the front axle actuator 76 and the left chamber of the rear axle actuator 78 to the tank or vice versa, depending on which cornering the motor vehicle is taking. The front axle actuator 76 and the rear axle actuator 78 can, for. B. hydraulic swivel motors or hydraulic cylinders, which can act on a stabilizer accordingly. The pressure for the front axle actuator 76 is sensed via a pressure sensor 80, while the pressure for the rear axle actuator 78 can be sensed via a pressure sensor 82. In the hydraulic circuit of the front axle actuator 76, downstream of the changeover valve area 72, there is a fail-safe valve 84 which, in the event of a fault, isolates the front axle actuator 76 from the rest of the hydraulic system by spring force and thus ensures a rigid stabilizer clamping. When compensatory movements of the stabilizer and the front axle actuator 76 are taken care of by suction valves 86 and 88, the front axle actuator 76 always remains filled with oil.

To achieve good control dynamics on the front axle actuator 76, it is appropriate if the control valve 5 for pressure control of the front axle actuator 76, the changeover valve 70 and the fail-safe valve 84 and the suction valves 86 and 88 are arranged in the immediate vicinity of the front axle actuator 76, behind the regulating or switching valves to ensure the lowest possible oil volumes and thus quick pressure build-up and dismantling times in the front axle actuator 76 Furthermore, for good control dynamics on the rear axle actuator 78, it is advantageous if the control valves and switching valves responsible for the rear axle actuator 78 are arranged in the immediate vicinity of the rear axle actuator 78. In this case, this is the pressure control valve 55, which adjusts the pressure at the rear axle actuator, and one or more check valves 90, 91. The pressure sensor 82 should also be positioned in the immediate vicinity of the rear axle actuator 78. So that the pressure control valve 55 can always regulate the pressure on the high-pressure side of the rear axle actuator 78, it is connected to both pressure areas of the rear axle actuator 78 via a check valve 90. Depending on whether the rear axle actuator area 92 or the rear axle actuator area 94 is to be subjected to high pressure, ie depending on whether the vehicle is turning left or right, the pressure control valve 55 is connected to the high-pressure-carrying area via the check valve 90 and is separated from the low-pressure area. leading area separated. The low-pressure area is connected to the tank area 23, 45 via the changeover valve 74. Instead of the check valve 90, two individual check valves 91, as shown in FIG. 4, can also be used. In this way, either the pressure-carrying area 98 or, in the other case, the pressure-carrying area 100 is connected to the supply line 96 to the pressure control valve 55, and the pressure-carrying area is thus separated from the non-pressure-carrying area. The entire area of the rear axle actuator 78 with the pressure control and non-return valves can be connected to the area of the front axle actuator 76 via expansion hoses 102 and 104. Furthermore, the pump 1 can be connected to the valve area of the front axle actuator 76 via a simple expansion hose 106.

Basically, the advantage of this circuit remains that the actuators can take the required amount of oil from the hydraulic circuit and the pump size is still determined by the maximum sum of the simultaneous volume flow requirement of both actuators and not by the sum of the maximum volume flows of the individual actuators, which is definitely can be higher than the former.

Furthermore, the advantage is retained that in the event of a lack of oil due to leaks or pump damage, the front axle circuit is always supplied with pressurized oil first, and a higher pressure is established at the front axle circuit in such situations. This guarantees an understeering and thus safe driving behavior of the vehicle.

In order to increase the control dynamics of the system, it is advantageous to position both the control valve and the pressure sensor close to the actuator. Therefore it is necessary maneuverable to position the rear axle control valve 55 and the rear axle pressure sensor 82 close to the rear axle.

By arranging check valves 90, 91 appropriately on the rear axle circuit, it is possible to maintain the mechanically positively coupled changeover valve 70 for the front axle actuator and the rear axle actuator. The switching valve 74 can remain mechanically coupled, and the rear axle control valve 55 can be positioned hydraulically downstream of the switching valve 70 close to the rear axle.

A further dynamic increase in the control behavior of the control valves 5 and 55 is possible by using a pilot control. As a result, the mass of the magnet is decoupled from the mass of the valve piston, so that a subordinate control loop is created that is significantly more dynamic.

The valve arrangement according to the invention thus allows the first advantage that the pressure on the rear axle actuator 78 can be set higher than the pressure on the front axle actuator 76, and the second advantage that the valves 55 and 90, 91 for the rear axle are arranged on the rear axle actuator 78 close to the rear axle and thus a much better dynamic is possible. The control valve 5 according to the invention adjusts the pressure at the front axle actuator 76 in that the control edge 47 throttles the further flow of the oil to the rear axle actuator 78. This results in a higher pressure at the front axle actuator 76 in accordance with the throttle resistance. The valve piston 7 itself is controlled by a pressure compensator. On the right side, a force acts on the surface 33, the z. B. is generated via a pilot pressure by means of pilot valve 39. In addition, a spring 37 acts in this direction. These forces push the valve piston 7 to the left. The volume flow to the rear axle actuator 78 is blocked. All oil from the pump 1 now flows to the front axle actuator 76 until a pressure has built up here, which acts on the left side 31 of the valve piston 7 and corresponds to the force on the right side 33 of the valve piston 7. The valve 5 now opens the control edge 47. Due to the effect of the balance of forces, the valve piston 7 always sets a pressure that is proportional to the force on the right-hand piston side 33. If the regulated pressure on the rear axle actuator 78 becomes higher than the pressure to be set on the front axle actuator 76, the valve 5 can no longer operate in its previous pressure control position, since in this position only higher pressures on the front axle actuator 76 than on the rear axle actuator 78 can be set. In the transition area, when the pressure at the rear axle actuator 78 becomes greater than at the front axle actuator 76, a control edge change of the valve piston 7 takes place. Since the pressure at the front axle actuator 76 would increase more than the force equilibrium at the valve piston 7 allows, the piston 7 moves further to the right and closes the inflow of the volume flow to the front axle actuator 76 with simultaneous further opening of the volume flow flow to the rear axle actuator 78 a higher pressure is set than on the front axle actuator 76. Should the pressure on the front axle actuator 76 increase further, the piston 7 moves further to the right until the control edge 51 opens to the tank 23 and the pressure in the front axle actuator area drops. Between the states "inflow to front axle actuator 76 open - outflow to tank 23 closed" and "inflow to front axle actuator 76 closed - outflow front axle actuator 76 to tank 23 open", there is now a control movement up to a control position which thus adjusts the pressure at front axle actuator 76 that it is proportional to the force applied to the right side 33 of the piston 7.

LIST OF REFERENCES

Hydraulic pump connection to the control valve control valve valve piston 1, 13 piston collars, 19,21 connection oil reservoir connection to the front axle actuator pilot control connection damping resistance piston surface control valve pilot chamber control oil line piston surface control valve spring chamber resistance spring pilot valve seat valve electromagnet tank area, 49,51 control edge connection to the rear axle actuator pressure control valve pilot valve control line to the rear axle chamber Piston area pressure control valve rear axle actuator Piston area spring chamber Pressure control valve rear axle actuator spring changeover valve 72.74 diverter valve range

76 front axle actuator

78 rear axle actuator

80.82 pressure sensor

84 Fail-safe valve

86.88 suction valve

90 check valve

92.94 rear axle actuator area

96 Pressure control valve supply line

98,100 pressure area rear axle actuator

102,104,106 expansion hoses

Claims

claims

1. Anti-roll system or roll stabilization system, each with a stabilizer and an actuator (76, 78), such as a swivel motor or cylinder, on the front axle and on the rear axle of a motor vehicle to influence the stabilizer and a common supply of the Actuators (76, 78) by a pump (1) and with a control valve (5), characterized in that the control valve (5) divides the pump volume flow into a front axle volume flow and a rear axle volume flow and controls the pressure at the front axle actuator (76).

2. Anti-roll system according to claim 1, characterized in that the control valve (5) on the front axle actuator (76) can allow a lower pressure than on the rear axle actuator.

3. Anti-roll system according to claim 1 or claim 2, characterized in that the control valve (5) has a pressure reducing function for the front axle actuator (76), in particular by an additional bypass tank drain (21) for the front axle volume flow.

4. Anti-roll system according to one of the preceding claims, characterized in that downstream of the control valve (5) a common switch valve (70) for the front axle actuator (76) and for the rear axle actuator (78) is arranged, which a switching of Front axle volume flow and the rear axle volume flow for a right or left movement of the vehicle.

5. Anti-roll stabilization according to one of the preceding claims, characterized in that a pressure control valve (55) is arranged downstream behind the area of the changeover valve (70) for the rear axle actuator (78), which pressure control valve (55) via one (90) or two check valves ( 91) can be connected to the higher pressure range of the rear axle actuator (78).

6. Anti-roll system according to one of the preceding claims, characterized in that the pressure control valve (55) for the rear axle pressure is arranged in the region of the rear axle actuator (78).

7. Anti-roll system according to one of the preceding claims, characterized in that a pressure sensor (82) for the rear axle pressure is arranged in the region of the rear axle actuator (78).

8. Anti-roll system according to one of the preceding claims, characterized in that the area of the rear axle actuator (78) by connections such. B. expansion hoses (102, 104), with the area of the front axle actuator (76).

9. Anti-roll system according to one of the preceding claims, characterized in that the control valve (5) and the changeover valve (70) are arranged in the region of the front axle actuator (76).

10. Anti-roll system according to one of the preceding claims, characterized in that the pressure control valve (55) for the rear axle pressure can regulate the pressure at the rear axle actuator (78) independently of the pressure level at the front axle actuator (76).

11. Anti-roll system according to one of the preceding claims, characterized in that a fail-safe valve (84) for the front axle actuator is arranged downstream of the area of the changeover valve (70) for the front axle actuator (76).

12. Anti-roll system according to one of the preceding claims, characterized in that suction valves (86, 88) for the front axle actuator (76) are arranged downstream of the fail-safe valve (84).

13. Anti-roll system according to one of the preceding claims, characterized in that by the control valve (5), for example in the event of a lack of oil, the front axle actuator (76) is preferred over the rear axle actuator (78) for supplying oil.

14. Anti-roll system according to one of the preceding claims, characterized in that the control valve (5) is pilot-controlled.

15. Anti-roll system according to one of the preceding claims, characterized in that the pressure control valve (55) is pilot-controlled for the rear axle actuator.