DE10227417A1 - Suspension system for motor vehicles has reversible hydraulic pump in connection between low end adjusting devices associated with wheels, for rolling stabilization - Google Patents

Abstract

The suspension system has at least one mechanical spring damping unit (3A,B) associated with a wheel (2A,B). It has a hydraulic low end adjusting device (4A,B) for the damping unit, and a hydraulic pump (6). The reversible pump is integrated in a controllable connection (5) between at least two adjusting devices of two wheels is provided to displace pressure mediums between the adjusting devices. Each damper unit has a damper element (12A,B) and a mechanical spring (13A,B) parallel to it. The adjusting device has a hydraulic cylinder (7A,B) with a piston rod (14A,B) connected to the axle (15A,B) of a wheel.

Description

The invention relates to a suspension system for a vehicle each with at least one mechanical assigned to a wheel Spring-damper device.

From the DE 198 55 310 C2 an active suspension system for vehicles or motor vehicles is known, which has a support unit between a vehicle body and vehicle wheels. The support units each include a. active stroke-adjustable actuator and a passive spring arranged in series. An abutment of the spring on the body side can be adjusted vertically relative to the vehicle body by means of the actuator or the hydraulic unit.

A damper is arranged parallel to the spring. This is provided between a vehicle wheel and the vehicle body, where it basically also possible supposed to be this damper between a vehicle wheel and the hydraulic unit parallel to To arrange the spring. The hydraulic unit is operated by a control valve arrangement controlled and is with a pressure source and via the control valve assembly fluidly connectable to a pressure medium reservoir.

This known active suspension system has However. the disadvantage that at a roll stabilization from the cylinders of the hydraulic units hydraulic oil on one side of the vehicle must be drained into the pressure medium reservoir, which was previously supplied with Compression work has been pumped into the cylinder. This creates an energy loss, which is why this active suspension system is an energetic unfavorable execution represents.

Object of the present invention is a suspension system for a vehicle with at least one assigned to a wheel mechanical spring damper device to disposal to provide with which an active energetically favorable roll compensation can be carried out.

According to the invention, this object is achieved with a Suspension system according to the characteristics of claim 1 solved.

The suspension system according to the invention with an actuator for moving pressure medium or hydraulic oil between at least two foot adjustment devices represents an energetically favorable solution of a suspension system with active roll stabilization, since pressure medium in the system during a Roll compensation without feed of compression energy from a foot adjustment device a wheel to at least one further foot point adjustment device another wheel on the same side of the vehicle and / or on the led other side of the vehicle becomes.

Other advantages and beneficial Embodiments of the subject of the invention are the claims Description and the drawing can be removed.

Six advantageous embodiments of the suspension system according to the invention are schematic in the drawing are shown in simplified form and are described in the following description explained in more detail.

It shows:

l a suspension system with a controllable connection between two base adjustment devices, wherein a hydraulic pump is designed as a reversible pump;

2 a suspension system according to 1 , wherein a damper element is integrated in a mechanical spring;

3 a suspension system with a unidirectional hydraulic pump, a pressure intensifier being provided to control the foot point adjustment devices;

4 a suspension system with a controllable connection between two base adjustment devices, wherein a stabilizer is arranged between two hydraulic cylinders of the base adjustment devices;

5 a suspension system according to 2 , where a stabilizer according to 4 is integrated and

6 a suspension system according to 5 , wherein a damping element is integrated in a mechanical spring.

Referring to 1 is a suspension system 1 a motor vehicle shown, each with a wheel 2A . 2 B associated mechanical spring-damper device 3A . 3B is trained. Furthermore, for each of the spring damper devices 3A . 3B a hydraulic foot point adjustment device 4A . 4B intended.

For active roll compensation between the two spring damper devices 3A . 3B To be able to perform, is between the two hydraulic base adjustment devices 4A . 4B a controllable connection 5 is provided, via which between the two hydraulic base adjustment devices 4A . 4B Pressure medium can be moved.

In the controllable connection 5 is a hydraulic pump 6 integrated, which is designed as a reversible pump. Between the hydraulic pump 6 and a hydraulic cylinder 7A the foot point adjustment device 4A as well as between the hydraulic pump 6 and a hydraulic cylinder 7B the Foot point adjustment device 4B is a blocking organ 8A respectively. 8B arranged, the locking members each as a 2/2-way valve 8A respectively. 8B are executed.

In addition, each branches in the area between the hydraulic pump 6 and the 2/2-way valve 8A or the 2/2-way valve 8B a line 9A respectively. 9B from which in a pressure medium reservoir 10 lead. The two lines 9A . 9B are each with controllable additional 2/2-way valves 11A . 11B executed by means of which the two lines 9A . 9B and a connection between the hydraulic pump 6 and the pressure medium reservoir 10 is lockable.

The two spring damper devices 3A . 3B are each with a damping element 12A . 12B and one mechanical spring each 13A . 13B executed, which are connected in parallel to each other. The hydraulic cylinders 7A . 7B are in line with the mechanical springs 13A . 13B switched, each with a piston rod 14A . 14B with one axis 15A . 15B of a wheel 2A . 2 B connected is. The connection between the piston rods 14A . 14B and the axes 15A . 15B each place a base of the springs 13A respectively. 13B The damper elements 12A . 12B are on the vehicle body on a body 17 a motor vehicle, not shown, and at its other end each on an axis 15A . 15B established.

The combination of an electric motor 16 driven reversible hydraulic pump 6 with several, preferably electromagnetically unlockable blocking elements or 2/2-way valves 8A . 8B . 11A . 11B enables the functions of sealing, suspension, roll stabilization, level control and kneeling with the suspension system 1 can be carried out in a simple manner.

The one for driving the hydraulic pump 6 used electric motor 16 is preferably designed as an asynchronous motor. An asynchronous motor is particularly suitable because it generates high torque at low speeds and has compact inverters, which is why it requires only a small amount of space.

With the preferably electromagnetically unlockable 2/2-way valves 8A . 8B . 11A . 11B are different functions of the suspension system in different switching positions of the valves 1 feasible. So they stay the two hydraulic cylinders 7A . 7B associated valves 8A . 8B closed if a purely passive vehicle without roll compensation is to be displayed.

The hydraulic pump is used for roll stabilization 6 a certain volume of pressure medium depending on the direction of rotation of the electric motor 16 from the hydraulic cylinder 7A one side of the vehicle in the hydraulic cylinder 7B the other side of the vehicle or vice versa.

To implement active roll compensation, the between the hydraulic cylinders 7A . 7B and the hydraulic pump 6 lying valves 8A . 8B opened and the in the lines 9A . 9B arranged valves 11A . 11B closed. The electric motor 16 drives the hydraulic pump 6 depending on the desired or required direction of displacement of the pressure medium to the left and to the right, the between the hydraulic pump 6 and the hydraulic cylinders 7A . 7B arranged valves 8A . 8B are open and in the to the pressure medium reservoir 10 leading lines arranged valves 11A . 11B are closed.

For a one-sided lowering of a vehicle side, the so-called kneeling, the valves assigned to the vehicle side are each 8A . 11A closed, and the valves 8B . 11B which are assigned to the other side of the vehicle are open. The hydraulic oil or the pressure medium of the loaded hydraulic cylinder 7B is drained into the pressure medium reservoir, which leads to the lowering of this side of the vehicle. In order to bring the vehicle back into a horizontal position, the valves 8A . 11A respectively. 8B , 11B in pairs opened or closed while the hydraulic pump the pressure medium in the hydraulic cylinder in question 7A respectively. 7B of the suspension system 1 promotes.

For example, the valve is used for level control 8A controlled so that it is in the flow position. That from the hydraulic pump 6 Pumped volume of pressure medium is from the pressure medium reservoir 10 in the hydraulic cylinder 7A promoted, creating one with the mechanical springs 13A . 13B connected body construction 17 is raised against a surface of the vehicle. To the body structure 17 all valves 8A . 8B . 11A . 11B opened so that the pressure medium back into the pressure medium reservoir 10 can be traced back. Protection of the hydraulic system of the suspension system 1 can be done through a pressure relief valve that is integrated into the lines that run the hydraulic cylinders 7A . 7B with the hydraulic pump 6 connect.

In the area of the base points of the mechanical springs 13A . 13B and the base points of the damper elements 12A . 12B a positive control, not shown, is provided. The positive guidance ensures that an adjustment of the base points of the mechanical springs 13A . 13B a simultaneous adjustment of the base points of the damper elements 12A . 12B and the axes tilt 15A . 15B is omitted.

In 2 to 6 are further embodiments of the suspension system 1 shown, wherein for identical and functionally identical components of the suspension system according to the invention the same reference numerals as in 1 be used.

2 shows the suspension system 1 out 1 , the spring damper devices 3A . 3B deviating from the spring damper devices 1 are executed. The damper elements 12A . 12B without positive guidance are coaxial to the mechanical springs 13A . 13B arranged, which on the one hand an adjustment of the piston rods 14A . 14B also directly on the damper elements 12A and 12B acts without positive guidance and on the other hand the spring damper devices 3A . 3B have a smaller overall space requirement.

In 3 is the suspension system 1 with spring damper devices 3A . 3B according to 1 shown, the controllable connection 5 between the two hydraulic cylinders 7A . 7B with a pressure intensifier 18 is executed.

The pressure translator 18 has four chambers 19A . 19B . 20A and 20B on, the chambers 19A and 19B each via a line branch of the controllable connection 5 with the hydraulic cylinders 7A respectively. 7B are connected. The chambers 20A and 20B are on further lines 21A . 21B from the hydraulic pump designed as a unidirectional pump 6 can be pressurized if one between the pressure intensifier 18 and the hydraulic pump 6 arranged 3/4-way valve 22 is in the appropriate switch position. The 3/4-way valve 22 can be held electromagnetically and mechanically with spring elements in one of the three possible switching positions.

The pressure translator 18 is with a fixed partition 23 and with two movable partitions designed as separating pistons 24A and 24B educated. The two movable partitions 24A . 24B are through a connecting piston 25 firmly connected. The connecting piston 25 is longitudinally sealed in the fixed partition 23 led and penetrates the two chambers 20A . 20B such that an effective area of the chambers 19A . 19B larger than the effective area of the chambers 20A . 20B is.

This means that the hydraulic pump has the same delivery rate 6 into the chambers 20A . 20B a larger amount of pressure medium to the respective hydraulic cylinder to be supplied 7A respectively. 7B fed.

It also has other connecting lines 26A . 26B the hydraulic pump 6 directly with the hydraulic cylinders 7A . 7B connectable. This is done in the connecting lines 26A . 26B one 3/3-way valve each 27A . 27B integrated. With the appropriate position of the valves 27A . 27B become the hydraulic cylinders 7A . 7B directly from the hydraulic pump 6 supplied with pressure medium. In a further switching position of the valves 27A . 27B becomes pressure medium from the hydraulic cylinders 7A . 7B into the pressure medium reservoir 10 dissipated.

There is also the possibility of applying pressure medium using the pressure intensifier 18 due to a pressure differential between the two hydraulic cylinders 7A . 7B without compressor performance of the hydraulic pump 6 from the hydraulic cylinder 7A to the other hydraulic cylinder 7B or move in the opposite direction. There is also the option of the 3/3-way valves 27A . 27B to switch such that in addition to that via the pressure intensifier 18 provided fluidic operative connection a further direct fluidic connection between the two hydraulic cylinders 7A . 7B consists.

Of course, it is at the discretion of the person skilled in the art to design the spring-damper devices of the suspension system 3 to be carried out such that in each case the damper element of a spring damper device in the 2 shown way is spatially integrated into the mechanical spring.

Referring to 4 is another embodiment of the suspension system 1 shown in the between the two hydraulic cylinders 7A . 7B a spring-like stabilizer extending in the vehicle transverse direction 28 is arranged. The stabilizer 28 is on the body side and on each of the axles 15A . 15B opposite ends of the hydraulic cylinders 7A . 7B established. Furthermore, the stabilizer 28 executed essentially trapezoidal, the upper shorter side at two points on the body 17 is set. Starting from the two attachment points of the stabilizer 28 on the body 17 it is designed with two break points, to which two branches adjoin, in the direction of the wheels 2A . 2 B run. The free end of the branches is with one of the two hydraulic cylinders 7A . 7B in the area of the connection point between the mechanical spring 13A respectively. 13B and the hydraulic cylinder 7A respectively. 7B connected.

The stabilizer 28 represents a spring element that only when the two spring damper devices deflect in opposite directions 3A . 3B works, ie when a wheel 2A respectively. 2 B undergoes a shift that the movement of the other wheel 2 B respectively. 2A is opposite. In such a case, the stabilizer works 28 , With the same deflection of the two wheels 2A . 2 B is the influence of the stabilizer 28 on the suspension system 1 only marginally.

An active roll stabilization takes place by adjusting the base of the spring damper devices 3A . 3B by means of the two hydraulic cylinders 7A . 7B , becomes the stabilizer 28 or the base point of the stabilizer 28 together with the base of the mechanical springs 13A . 13B adjusted, which is why the in 3 shown fixing the stabilizer 28 represents an energetically favorable arrangement.

In the 4 to 6 Embodiments of the suspension system shown are preferably used in front axle systems of vehicles, the in 4 hydraulic system shown in 3 hydraulic system shown without the hydraulic pressure intensifier corresponds. Of course, it is within the discretion of the person skilled in the art to determine the embodiment of the suspension Systems 1 according to 4 to 6 if necessary with the in 3 to combine the pressure translator shown.

5 shows an embodiment of the suspension system 1 which is a combination of the stabilizer 28 according to 4 and the hydraulic control of the two hydraulic cylinders 7A . 7B in the in 1 shown way.

In 6 is another embodiment of the suspension system 1 shown, which is essentially the suspension system 5 equivalent. Only the spring damper devices 3A . 3B are executed differently and correspond to that in 2 illustrated embodiment in which the damper elements 12A . 12B inside the mechanical springs or coil springs 13A . 13B are arranged. So that the base points of the mechanical springs 13A . 13B and the damper elements 12A . 12B together adjusted who, which is particularly advantageous in a strut assembly.

This variant of the spring damper devices 3A . 3B compared to the arrangement of the damper elements which is spatially offset from one another 12A . 12B and the mechanical springs 13A . 13B represents an energetically more favorable embodiment, although the coaxial arrangement of the damper elements 12A . 12B and the feathers 13A . 13B requires a slightly higher control effort than the spatially separate arrangement.

1

suspension system

2A, 2B

wheel

3A, 3B

Spring-damper device

4A, 4B

hydraulic Foot point adjustment device

5

controllable connection

6

hydraulic pump

7A, 7B

hydraulic cylinders

8A, 8B

Blocking member, 2/2 way valve

9A, 9B

management

10

Pressure fluid reservoir

11A, 11B

second 2/2 way valve

12A, 12B

damper element

13A, 13B

mechanical feather

14A, 14B

piston rod

15A, 15B

axis

16

electric motor

17

body

18

Pressure intensifier

19A, 19B

chamber of the pressure translator

20A, 20B

chamber of the pressure translator

21A, 21B

cables

22

3/4 way valve

23

partition

24A, 24B

partition wall

25

connecting piston

26A, 26B

interconnectors

27A, 27B

3/3-way valve

28

stabilizer

Claims (8)

Suspension system ( 1 ) for a vehicle with at least one wheel each ( 2A . 2 B ) assigned mechanical spring damper device ( 3A . 3B ), with a hydraulic foot point adjustment device ( 4A . 4B ) for the spring damper device ( 3A . 3B ) and with a hydraulic pump ( 6 ), wherein a controllable connection (5) between at least two base adjustment devices ( 4A . 4B ) two wheels ( 2A . 2 B ) for moving pressure medium between the foot point adjustment devices ( 4A . 4B ) is provided. Suspension system according to claim 1, characterized in that a spring damper device ( 3A . 3B ) at least one damper element ( 12A . 128 ) and a mechanical spring ( 13A . 13B ) that are connected in parallel to each other. Suspension system according to claim 2, characterized in that a foot point adjusting device ( 4A . 4B ) a hydraulic cylinder ( 7A . 7B ), the piston rod ( 14A . 14B ) with one axis ( 15A . 15B ) of a wheel ( 2A . 2 B ) is connected, the hydraulic cylinder ( 7A . 7B ) in series with the mechanical spring ( 13A . 13B ) is switched. Suspension system according to one of claims 1 to 3, characterized in that the hydraulic pump ( 6 ) as a reversible pump for moving pressure medium between at least two base point adjustment devices ( 4A . 4B ) is formed, the hydraulic pump ( 6 ) is integrated in the controllable connection (5). Suspension system according to claim 4, characterized in that between the hydraulic pump ( 6 ) and one of the hydraulic cylinders ( 7A . 7B ) a blocking organ ( 8A . 8B ; 27A . 27B ) is arranged. Suspension system according to claim 4 or 5, characterized in that between the hydraulic pump ( 6 ) and the hydraulic cylinder ( 7A . 7B ) a line ( 9A . 9B ) to a pressure medium reservoir ( 10 ) branches off, which has a further blocking element ( 11A . 11B ; 27A . 27B ) opposite the pressure medium reservoir ( 10 ) can be blocked. Suspension system according to claim 5 or 6, characterized in that between the hydraulic pump ( 6 ) and a hydraulic cylinder ( 7A . 7B ) a foot point adjustment device ( 4A . 4B ) a pressure translator ( 18 ) is arranged. Suspension system according to one of claims 3 to 7, characterized in that between two hydraulic cylinders arranged adjacent in the transverse direction of the vehicle ( 7A . 7B ) a spring-like stabilizer extending in the transverse direction of the vehicle ( 28 ) is arranged, the body side and in each case on that of the axle ( 15A . 15B ) opposite end of the hydraulic cylinder ( 7A . 7B ) is set.