DE102004059544B4 - Suspension for a vehicle - Google Patents

Abstract

Wheel suspension for a vehicle (7), comprising a carrier element (5), a wheel carrier (1) arranged at a distance from the carrier element (5) and a wheel (14) rotatably mounted on the wheel carrier (1), wherein the wheel carrier (1) engages with the wheel carrier (1) Carrier element (5) via a first guide means (3) and a first pivotable connecting means (11) is connected and the wheel carrier (1) with the carrier element (5) via a second guide means (4, 2) and a second pivotable connecting means (13; 8), characterized in that
- In the first pivotable connecting means (11), a first force measuring device is integrated and
- in the second pivotable connecting means (13; 8) a second force measuring device (24, 25) and / or an angle measuring device (17, 18) is integrated.

Description

The The present invention relates to a suspension for a vehicle, comprising a support element, one at a distance from the carrier element arranged wheel carrier and one on the wheel carrier rotatably mounted wheel, wherein the wheel carrier with the carrier element via a first guide and a first pivotable connection means is connected and the wheel carrier with the carrier element via a second guide means and a second pivotable connecting means is connected.

Such suspensions are known from the prior art, for example from the DE 10 2004 030 463 A1 , known. In this case, the wheel force or a force acting on the wheel for use as an input variable, for example in a brake slip-based control system or an active steering momentarily determined only on the basis of an estimate of the operating point of the tire in his characteristic (slip curve) and is due to the pronounced non-linearity and complexity of the transmission properties of the tire with significant losses of accuracy and validity. This applies in particular to low coefficients of friction and strongly unsteady driving conditions.

task The invention is a suspension of the aforementioned Art to continue to form so that acting on the wheel forces higher accuracy can be determined.

These Task is according to the invention with a Arm solved according to claim 1. Preferred developments are given in the dependent claims.

The Inventive suspension for a vehicle, In particular motor vehicle has a support element, one at a distance to the support element arranged wheel carrier and one rotatable on the wheel carrier stored wheel, wherein the wheel carrier with the support element via a first guide and a first pivotable connecting means is connected and wherein the wheel carrier further with the carrier element via a second guide means and a second pivotable connecting means is connected. there In the first pivotable connecting means is a first force measuring device integrated and in the second pivotable connection means a second force measuring device and / or an angle measuring device integrated.

With the suspension of the invention is it is possible the forces acting on the wheel from measured values that are in the wheel suspension itself, ie in relative or immediate proximity be added to the wheel. Is the geometry of the suspension known, so can with two force measurements at different locations of the suspension acting on the contact point of the wheel forces, in particular the longitudinal force and the lateral force can be determined. According to an alternative of the invention Is it possible, these two forces too to determine by a force measurement and an angle measurement, wherein the angle measurement, the pivoting and / or rotation of the second guide means across from the wheel carrier or the carrier element describes.

Further can the wheel carrier also about additional guide means and pivotable connecting means to be connected to the carrier element.

The first pivotable connecting means is preferred as an elastomeric bearing formed over which z. B. the first guide means pivotable with the carrier element connected is. In this case, the first guide means wheel carrier side via a Ball joint to the wheel carrier be connected.

The second pivotable connection means may according to a first alternative also be an elastomeric bearing, in which the second force measuring device is integrated. The second guide is preferred over this elastomeric bearing pivotally connected to the carrier element and can wheel carrier side over a Ball joint on the wheel carrier be connected.

According to a second alternative, the second pivotable connecting means may be a spherical joint or a ball joint, via which the second guide means is pivotally and rotatably connected to the wheel carrier or to the carrier element, wherein in this ball joint or spherical joint, the angle measuring device is integrated. If the second guide means is connected to the carrier element via the second pivotable connection means, the second guide means is preferably connected to the wheel carrier via a ball joint on the wheel carrier side. If, however, the second guide means is connected to the wheel carrier via the second pivotable connection means, the second guide means is preferably connected to the carrier element via an elastomer bearing. But it is also possible that the second guide means is connected both to the wheel carrier and to the carrier element via a respective ball joint or a spherical joint, wherein one of these two joints is the second pivotable connecting means and having the angle measuring device. The angle measuring device can a gimbal angle, in particular but especially two gimbal angle and / or a rotation or preferably also measure at least one rotational angle.

Under a spherical one Joint should be understood here in particular an elastomer or rubber hinge which is movable in the same spatial directions as a Ball joint. For this, the joint can be an inner part and an outer part have, wherein the inner part with the interposition of an elastomeric body in the outer part is arranged. In principle, a spherical joint is also spherical Joint suitable. However, you can then at the wheel occurring shocks almost undamped to the support element and thus be passed to the vehicle body of the vehicle.

Further can in the second pivotable connecting means, both the second Force measuring device and the angle measuring device integrated be. Is the second pivotable connection means as an elastomeric bearing trained, so can measured both a force and at least one gimbal angle become.

The first guiding means is preferably a wishbone or a transverse rocker, wherein the second guide means as a leader or may also be designed as a wishbone. Is the second guide means a wishbone, the second guide means preferably forms one upper wishbone, whereas the first guide means as the lower wishbone or lower transverse rocker can be formed.

When Force sensors can z. B. piezoelectric elements can be used. As one on an elastomeric bearing acting force but regularly with one Deformation of the arranged in the elastomeric bearing elastomer body is accompanied it is also possible to use a displacement sensor as a force sensor, with knowledge the bearing stiffness of the elastomeric bearing of the measured path can be concluded on the acting force. It has become Magnetic sensors proved to be particularly suitable, so that the first force measuring device and optionally the second force measuring device each having a magnet and a magnetic field sensitive sensor can, which is designed in particular as a magnetoresistive sensor. Further the angle measuring device preferably has a magnet and at least a magnetoresistive sensor designed in particular as magnetoresistive sensor Sensor on.

The two force measuring devices or the first force measuring device and the angle measuring device can be electrically connected to an evaluation device, from the preferably based on the measurements provided by the sensors two the wheel acting and in particular perpendicular to each other personnel are determinable. These two forces are e.g. around the acting in the Radaufstandspunkt on the wheel longitudinal and transverse forces and optionally the additive superimposed inertia forces the wheeled movements in longitudinal and transverse direction. Under longitudinal force is preferably a rolling direction of the wheel or in driving or longitudinal direction the vehicle acting force, whereas the transverse force in particular aligned perpendicular to the longitudinal force is. Furthermore, the wheel preferably has a tire over which the wheel in contact with a surface or with a roadway stands. The wheel contact point is in this case the point or Area where the tire comes in contact with the ground.

Around to increase the accuracy with which the forces acting on the wheel are detected, have the first pivotable connection means and the second pivotable connection means prefers a distance to each other.

The The invention further relates to a vehicle, in particular a motor vehicle, with a vehicle body and at least one suspension according to the invention, wherein the carrier element is part of the vehicle body. The suspension can be in accordance with all Be further developed above embodiments. Especially Is it possible, To provide the vehicle with four suspension according to the invention. In this Case can the carrier elements the respective wheel suspensions be firmly connected or merge.

The Invention also relates to the use of a suspension according to the invention wherein means the first force measuring device is determined a first measured value, by means of the second force-measuring device and / or the angle-measuring device a second measured value is determined and based on these two Measurements acting on the wheel and perpendicular to each other personnel be determined. With these forces these are, in particular, the longitudinal and Transverse forces. Again, the suspension can according to all Be further developed above embodiments.

With the help of the intelligent joint sensor system, which is arranged in the handlebar support of the suspension in a suitable way, wheel-individually the plane, preferably related to the Radaufstandspunkt Radkraftvektoren or force vectors at Radaufstandspunkt, which are formed from lateral force and longitudinal force, as input to higher-level systems for vehicle dynamics control be calculated. The determination is made on the basis of Joint movements under the influence of external wheel forces. Furthermore, resonance phenomena, for example in the region of the wheel natural frequency, can be determined metrologically and used as an input variable for higher-level systems for regulating or adapting chassis force elements, for example for setting damper forces or bearing stiffnesses.

At the magnetoresistive measuring principle of these sensors can be the field line direction a permanent magnet in a calibrated steel beam (ball) be measured relative to the sensor, so that a detection of tilting movements between magnet and sensor in a large angular range high resolution is possible. With appropriate sensor arrangement can also relative displacements be detected between the magnet and the sensor, so that the deflection of the joint is determinable. The measured variable can be characterized by a differentiating Member in addition be derived in time, so that also relative (rotational) speeds can be measured. The intelligent angle joint can be achieved through the integration of sensors formed together with particular different suspension joint types become.

For the indirect Capture of these wheel forces can be two Sensors are used per wheel, since the respective determination of the Along- and side force separated in different load paths and through two different types of joints or by two at different Places arranged joint types takes place.

By the indirect measurement or calculation of the plane force vector on Rad can parent Systems for controlling the driving dynamics (ESP, active steering) an optimal Input for detection of forces acting on the vehicle to disposal be put. The control quality of systems for active yaw stabilization (yaw moment compensation) is thus significantly improved. The wheel force can not only as a pilot control variable in the slip control or the yaw moment compensation used by the control system but directly as a feedback size, thereby the robustness and the possible Dynamics of the controller can be improved. Also suitable for interventions on surfaces Low-friction value, an optimized control can be implemented.

The Invention will be described below with reference to a preferred embodiment described with reference to the drawing. In the drawing show:

1 a schematic view of an embodiment of the suspension according to the invention,

2 a section from 1 , from which in particular the upper control arm can be seen,

3 a schematic view of a ball joint with integrated angle measuring device,

4 a section from 1 , from which in particular the guide arm is evident,

5 a schematic view of an elastomer bearing with integrated force measuring device and

6 a section from 1 , from which in particular the lower arm can be seen.

Out 1 is a schematic view of an embodiment of the suspension according to the invention can be seen, wherein a wheel carrier 1 over an upper wishbone 2 , a lower wishbone 3 and a guide arm 4 with a carrier element 5 connected, which part of a vehicle body 6 a partially illustrated motor vehicle 7 is. The upper wishbone 2 is about a ball joint 8th with the wheel carrier 1 and a spherical joint 9 with the carrier element 5 connected. The lower wishbone 3 is about a ball joint 10 with the wheel carrier 1 and an elastomeric bearing 11 with the carrier element 5 connected. Furthermore, the guide arm 4 over a ball joint 12 with the wheel carrier 1 and an elastomeric bearing 13 with the carrier element 5 connected. In this case, the wheel carrier side ball joints 8th . 10 and 12 each at a distance from each other. Furthermore, carrier element side have the spherical joint 9 as well as the two elastomeric bearings 11 and 13 each at a distance from each other.

At the wheel carrier 1 is a tire or a wheel 14 rotatably mounted, which in a Radaufstandspunkt 15 in contact with a roadway shown schematically 16 stands. At the wheel contact point 15 grab a longitudinal force Fx and a lateral force Fy on the wheel 14 at, wherein these two forces can be determined by means of the suspension of the invention. The spatial directions x, y and z are indicated in a coordinate system.

According to a first alternative of the embodiment is in the ball joint 8th integrated an angle measuring device which can determine the gimbal angle τ, which is the upper arm 2 opposite the wheel carrier 1 occupies. The wishbone 2 is partial 2 can be seen, where at the gimbal angle τ or those angles are to be understood by which or around which the upper wishbone 2 versus above the wheel carrier 1 tilted and / or twisted. With knowledge of the arrangement of the elements of the suspension and / or the dynamic behavior of these elements can be calculated based on the gimbal angle τ, the longitudinal force Fx, since the angle τ is a function of the longitudinal force Fx. If a braking of the vehicle is considered, then τ is a function of the braking force Fx_Brems (τ = f (Fx_Brems)).

Out 3 is a schematic view of the ball joint 8th it can be seen in which a magnet 17 and a magnetic field sensitive sensor 18 comprising angle measuring device is integrated. In this case, the magnetic field-sensitive sensor 18 in the case 20 of the ball joint 8th arranged, whereas the magnet 17 in the ball stud 19 of the ball joint 8th is arranged, which is rotatable and pivotable in the ball joint housing 20 is stored. Alternatively, the magnet 17 and magnetic field sensitive sensor 18 formed angle measuring device also in the spherical joint 9 be integrated. The ball joint housing 20 is especially firm with the upper wishbone 2 connected, whereas the ball stud 19 preferably firmly with the wheel carrier 1 or with the carrier element 5 connected or vice versa. The coordinates x 'and z' in the designation x'z 'plane represent in 3 two axes of a local, handlebar related coordinate system, the longitudinal direction of the handlebar 2 defines the reference direction x '.

According to a second alternative of the embodiment is in the elastomeric bearing 13 a Wegmessvorrichtung integrated, wherein the guide link 4 is aligned clearly in the longitudinal direction x, which is fragmentary 4 is apparent. The elastomeric bearing 13 is schematic in 5 shown, wherein between one on the support element 5 attached inner part 21 and one on the guide arm 4 attached outer sleeve 22 an elastomeric body 23 is arranged. In the elastomeric body 23 is a magnet 24 arranged, whereas on the inner part 21 a magnetic field sensitive sensor 25 is attached. One in the longitudinal direction of the guide arm 4 acting force Fx 'deforms the elastomer body 23 so that the outer sleeve 22 around a path X 'relative to the inner part 21 is moved. This relative displacement X 'is dependent on the force Fx' and can be detected by the distance measuring device, so that with knowledge of the radial bearing stiffness Celast of the elastomer bearing 13 the force Fx 'can be determined.

Thus, the path measuring device as a whole forms a force measuring device. The coordinates x 'and y' in the designation x'y 'plane represent in 5 two axes of a local, handlebar related coordinate system, the longitudinal direction of the handlebar 4 defines the reference direction x '.

Knowing the arrangement of the elements of the suspension and / or the dynamic behavior of these elements can be from the force Fx 'on the Aufstandspunkt 15 of the wheel 14 Determine related acting longitudinal force Fx.

Consequently two alternatives for measuring the longitudinal force Fx have been presented, where the two alternatives can also be used together to z. B. the accuracy with which the longitudinal force Fx are determined can, increase.

To determine the transverse force Fy is in the elastomeric bearing 11 also integrated with a magnet and a magnetic field-sensitive sensor path measuring device, wherein the elastomeric bearing 11 essentially identical to the elastomeric bearing 13 is designed so that a more detailed representation of the elastomeric bearing 11 is waived. The term identical in construction is not interpreted too narrowly, so that the geometric dimensions of the elastomer bearing and / or the rigidity of the elastomer body may differ. From the relative displacement between the inner part and the outer sleeve of the elastomeric bearing 11 can be with knowledge of the radial bearing stiffness Celast of the elastomer bearing 11 on the elastomeric bearing 11 over the lower wishbone 3 acting force Fy 'determine which fragmentary 6 is apparent. Thus, also forms in the elastomeric bearing 11 integrated Wegmessvorrichtung a force measuring device. With knowledge of the arrangement of the elements of the suspension and / or the dynamic properties of these elements can be from the force Fy 'on the Aufstandspunkt 15 of the wheel 14 Determine related acting lateral force Fy.

An evaluation device is used to calculate or determine the effective wheel forces Fx and Fy on the basis of the values measured by means of the sensors 26 that are preferred in the motor vehicle 7 is arranged and may have a digital computer. The path measuring devices and angle measuring device or the sensors are electrically connected to the evaluation unit 26 connected. Alternatively, it is possible to integrate a separate evaluation device into each of the measuring bearings or measuring joints.

Consequently is easily created a suspension for a motor vehicle, with the forces acting on the wheel can be determined very accurately. As sensors in particular magnetoresistive sensors and as Magnets preferably permanent magnets used.

The wheel side force Fy can be measured by measuring the radial attitude deflection of the wishbone or swingarm bushings 11 with knowledge of the radial bearing stiffness and by the Radauf suspension kinematics defined load path along the handlebar 3 (from joint 10 to camp 11 ). The reaction force Fy 'acts radially on the bearing 11 ,

The wheel longitudinal force Fx can be determined either by measuring the radial bearing deflection of a guide armature bushing which acts primarily in the vehicle longitudinal direction 13 or by measuring the elastokinematically related gimbals of a wishbone ball joint 8th or spherical joints 9 (eg braking force - there occurs a tilting of the control arm 2 by the Aufziehbewegung the wheel carrier 1 on). This process takes place with knowledge of the load path along the handlebar 4 (from joint 12 to camp 13 ) and the radial bearing stiffness Celast of the guide arm Bushings 13 and / or the elastokinematic effects when introducing braking forces (wishbone ball joint 8th or spherical joint 9 ).

Furthermore, the resulting from possible Radeigen movements inertia forces of the wheel 14 also be determined via the measurement of the reaction loads in the sensor joints (joints with integrated force and / or angle measuring device), in the x and y directions.

1

wheel carrier

2

upper wishbone

3

lower wishbone

4

Trailing arm

5

support element

6

vehicle body

7

motor vehicle

8th

ball joint

9

spherical joint

10

ball joint

11

elastomeric bearings

12

ball joint

13

elastomeric bearings

14

wheel

15

wheel contact

16

roadway

17

magnet

18

sensitive to magnetic fields sensor

19

ball pin

20

Ball joint housing

21

inner part

22

outer sleeve

23

elastomer body

24

magnet

25

sensitive to magnetic fields sensor

26

evaluation

Fx

longitudinal force on wheel

Fy

lateral force on wheel

Fx '

force along the guide link

fy '

force along the lower wishbone

τ

gimbal Angle of the upper arm

x

longitudinal direction

y

transversely

z

vertical direction

X '

path or relative shift

Claims (13)

Suspension for a vehicle ( 7 ), with a carrier element ( 5 ), one at a distance from the carrier element ( 5 ) arranged wheel carrier ( 1 ) and one on the wheel carrier ( 1 ) rotatably mounted wheel ( 14 ), wherein the wheel carrier ( 1 ) with the carrier element ( 5 ) via a first guide means ( 3 ) and a first pivotable connection means ( 11 ) and the wheel carrier ( 1 ) with the carrier element ( 5 ) via a second guide means ( 4 ; 2 ) and a second pivotable connecting means ( 13 ; 8th ), characterized in that - in the first pivotable connecting means ( 11 ) a first force measuring device is integrated and - in the second pivotable connecting means ( 13 ; 8th ) a second force measuring device ( 24 . 25 ) and / or an angle measuring device ( 17 . 18 ) is integrated. Wheel suspension according to claim 1, characterized in that the first pivotable connecting means ( 11 ) is an elastomeric bearing. Wheel suspension according to claim 1 or 2, characterized in that the second pivotable connecting means ( 13 ) is an elastomeric bearing into which the second force measuring device ( 24 . 25 ) is integrated. Wheel suspension according to claim 1 or 2, characterized in that the second pivotable connecting means ( 8th ) is a spherical joint or a ball joint into which the angle measuring device ( 17 . 18 ) is integrated. Wheel suspension according to one of the preceding claims, characterized in that the first guide means ( 3 ) is a wishbone or a transverse rocker. Wheel suspension according to one of the preceding claims, characterized in that the second guide means ( 4 ) is a guide arm. Wheel suspension according to one of claims 1 to 5, characterized in that the second guide means ( 2 ) is a wishbone. Wheel suspension according to one of the preceding claims, characterized in that the first force measuring device and the second force measuring device ( 24 . 25 ) and / or the angle measuring device ( 17 . 18 ) each have a magnet and a magnetic field sensitive sensor. Wheel suspension according to claim 8, characterized in that the magnetic field-sensitive sensors ( 18 . 25 ) are magnetoresistive sensors. Wheel suspension according to one of the preceding claims, characterized in that the first force measuring device and the second force measuring device ( 24 . 25 ) and / or the angle measuring device ( 17 . 18 ) electrically with an evaluation device ( 26 ) are connected. Wheel suspension according to claim 10, characterized in that of the evaluation device ( 26 ) two on the wheel ( 14 ) and mutually perpendicular forces (Fx, Fy) are determinable. Wheel suspension according to claim 10 or 11, characterized in that of the evaluation device ( 26 ) are derived from Radeigen movements inertia forces of the wheel in two mutually perpendicular directions can be determined. Wheel suspension according to one or more of the preceding claims 1 to 12, characterized in that the carrier element ( 5 ) a part of a vehicle body ( 6 ) of the vehicle ( 7 ).