DE102019209592A1 - Rigid axle for a motor vehicle and a method for damping the lift and roll of a motor vehicle with a rigid axle - Google Patents

Abstract

The invention relates to a rigid axle (1) for a motor vehicle, comprising an axle body (2), at each of the ends of which a wheel suspension (3a, 3b) for at least indirect attachment of a wheel (4a, 4b) to the axle body (2) is arranged, wherein the axle body (2) in the area of the respective wheel suspension (3a, 3b) comprises at least one damper (6a, 6b) for supporting a vehicle body of the motor vehicle, characterized by a fluid line (5) for guiding a fluid between the dampers (6a, 6b) , wherein a device (7) for controlling the fluid flow is provided in order to generate a damping force for the stroke and roll damping of the motor vehicle as a function of an opposing wheel stroke of the motor vehicle. The invention also relates to a motor vehicle and a method for damping the lift and roll of the motor vehicle.

Description

The present invention relates to a rigid axle for a motor vehicle, comprising an axle body, at the ends of which a wheel suspension for at least indirect fastening of a wheel to the axle body is arranged. In the area of the respective wheel suspension, the axle body comprises at least one damper for supporting a vehicle body of the motor vehicle. The invention also relates to a motor vehicle and a method for damping the lift and roll of the motor vehicle.

From the DE 20 2012 005 687 U1 discloses a device for damping a rolling motion for a motor vehicle. This device connects two wheels on an axle of the motor vehicle and creates a dependency for vertical movement of both wheels. A torsionally rigid rotating tube with lever arms at the ends of the tube, which is mounted transversely to the direction of travel and floating, is provided, the rotating tube being mounted by the length of the arms in front of or behind the relevant rigid axle or on the wishbone. The pivot rod is articulated with the arms on the wishbone of the wheel suspension or on the sides of the rigid axle, but directly and without coupling rods, so that the distance of the tube from the attachment to the rigid axle or the wishbone is always constant. Furthermore, the pivot rod is floatingly attached to the body or the frame of the vehicle, so that it nods to the side of the vehicle and rotates around the vehicle axis. The rotary tube is suspended from two approximately vertical connecting elements under the body or the frame, one of the connecting elements being a shock absorber and the other being a coupling rod.

Based on the prior art, the present invention is based on the object of proposing a rigid axle for a motor vehicle which creates improved driving comfort. The object is achieved by the subject matter of claim 1. Further advantageous embodiments can be found in the dependent claims.

A rigid axle according to the invention for a motor vehicle comprises an axle body, at the ends of which a wheel suspension for at least indirect fastening of a wheel to the axle body is arranged, the axle body in the area of the respective wheel suspension including at least one damper for supporting a vehicle body of the motor vehicle, with a fluid line for Guiding of a fluid is provided between the dampers, a device for controlling the fluid flow is also provided in order to generate a damping force for the stroke and roll damping of the motor vehicle as a function of an opposing wheel stroke of the motor vehicle.

If the motor vehicle drives over an obstacle, for example, or drives through a pothole, a positive or negative wheel stroke of the respective wheel arranged at the end of the axle body occurs. The wheel is shifted upwards, that is to say in the direction of the body of the motor vehicle, or downwards, that is to say away from the body. The other wheel arranged at the opposite end of the axle body can remain unchanged in its relative position, depending on the driving situation of the motor vehicle, or it can perform the same or opposite lifting movement. When the motor vehicle is in motion, there are often different lifting movements of the wheels, which are passed into the body via the shock absorbers and suspension struts of the motor vehicle and there trigger a lifting and / or rolling movement that negatively affects the driving comfort of the motor vehicle. If the wheels at one end of the axle body move in opposite directions relative to the wheels at the opposite end of the axle body, the term wheel travel is in opposite directions.

Lifting and rolling movements essentially act around the longitudinal axis of the motor vehicle. During a lifting movement, the motor vehicle is raised or lowered on one of the two long sides as a result of the wheel stroke, that is to say for example when driving over an obstacle or when driving through a pothole. Rolling movements occur, for example, when the motor vehicle is cornering. The lifting and rolling movements of the motor vehicle are counteracted by the rigid axle with the device in that the fluid is guided from one side of the vehicle to the other during a wheel stroke in the opposite direction and the associated compression movement of the left and right wheel suspension.

The design and functioning of the rigid axle is described below using the example of a wheel stroke in opposite directions, with only a first damper and a first wheel being arranged on the first wheel suspension at the first end of the rigid axle, and with only a second damper and one at the second end of the rigid axle second wheel is arranged on the second wheel suspension.

During the opposing wheel stroke of the wheels, for example when the left wheel on the first wheel suspension moves up and the right wheel moves down on the second wheel suspension, a fluid flow of the fluid arranged in the fluid line is introduced or initiated, the fluid either from the first damper in the direction of the second damper or vice versa a flow velocity flows. The device is directly connected to the fluid line and the fluid preferably flows through it. The device influences or controls the fluid flow in such a way that flow properties of the fluid, such as for example a flow velocity or a fluid pressure, are changed. More precisely, the device changes, in particular, a damping coefficient of the fluid. By changing the damping coefficient of the fluid by means of the device, a damping force is generated which dampens the situational lifting and rolling movement of the motor vehicle in order to adapt the driving comfort of the motor vehicle to the respective situation and thereby improve it.

According to a first embodiment, the device comprises a valve unit. The dampers are preferably hydraulically connected to one another via the fluid line, the fluid flowing through the valve unit or at least one hydraulic valve of the valve unit. The fluid line is thus a hydraulic line and the fluid is preferably a hydraulic oil, the hydraulic oil flowing as a result of the wheel stroke from one vehicle side to the other or from the first damper to the second damper or vice versa. The valve unit has the task of generating at least one defined damping force by controlling the fluid flow or by changing the damping coefficient, which causes the stroke and roll damping in order to improve the driving comfort of the motor vehicle.

The damping force is therefore only generated as soon as an opposing compression or an opposing wheel stroke occurs and the fluid is thus set in motion and accordingly has a certain flow speed. Using the damping coefficient defined by the valve unit, the damping force is then applied in opposition to the rolling or rolling movement of the motor vehicle. It is advantageous that excessive body damping or minimum damping is avoided when the wheel stroke is in the same direction and a harmonious relationship between stroke and roll damping can be found.

With compression in the same direction, the fluid velocity is almost zero, since there is no relative stroke movement of the wheels and therefore the fluid does not flow from one to the other side of the motor vehicle or from one damper to the other. “From one side of the motor vehicle to the other” means that the fluid flows from the left side to the right side of the motor vehicle or vice versa.

According to a second embodiment, the device comprises at least one electromagnet. In this case, the fluid is preferably a magnetized fluid or a magnetorheological fluid, which is set into a flow movement between the dampers as a result of an opposing wheel stroke in the fluid line. By means of the respective electromagnet, a magnetic field is generated that acts on the magnetorheological fluid in such a way that the flow properties, in particular the viscosity of the fluid, are influenced. Consequently, a damping coefficient of the fluid is set by the magnetic field of the electromagnet which generates a damping force which dampens the lifting and rolling movement of the motor vehicle in order to improve the driving comfort of the motor vehicle as a result.

Regardless of whether the device comprises a valve unit or at least one electromagnet, the device can be designed as a passive, semi-active or active system.

In a passive system, the device has a single predefined damping coefficient, so that only a single predefined damping force can be generated. During the wheel stroke in opposite directions, the fluid is guided from one side of the motor vehicle to the other. Using the example of the valve unit, the device has a hydraulic valve with a certain predefined damping coefficient of the fluid, which generates a certain damping force in order to dampen the lifting and rolling movement of the motor vehicle.

Using the example of the electromagnet, a predefined magnetic field acts during the opposing wheel stroke, which influences the flow properties of the magnetorheological fluid in such a way that a certain, predefined damping coefficient is specified, which generates a certain damping force to dampen the lifting and rolling movement of the motor vehicle.

A device designed as a semi-active system is preferably set up to set different predefined damping coefficients or damping forces as a function of the wheel stroke of the motor vehicle. In other words, using the valve unit as an example, several valves or hydraulic valves can be provided that have different predefined damping coefficients, so that depending on the wheel stroke in opposite directions, it is possible to switch between the valves in order to create a specific, predefined valve with a selected valve Set or select the damping coefficient to generate a defined damping force.

Alternatively, several electromagnets with different predefined magnetic field strengths can be provided, so that at least one of the electromagnets is activated as a function of the opposing wheel stroke in order to set or select a certain damping coefficient for generating a defined damping force. For both examples, the device is connected to a control unit that monitors the current driving situation of the motor vehicle.

An active system is to be understood as meaning that the device preferably comprises at least one pump, which is furthermore preferably fluidically connected to at least one fluid reservoir. The pump, which is hydraulically connected to the fluid reservoir and which can be controlled and regulated, for example, by a control unit, produces a corresponding fluid, for example either hydraulic oil or a magnetorheological fluid, as a result of the opposing wheel stroke and depending on the compression movement of the dampers or the spring units fed from the fluid reservoir into the fluid line, so that a fluid pressure is changed within the fluid line. In other words, the pump can generate an additional damping force. Depending on the requirements placed on the rigid axle, the damping force, for example, can be increased as the wheel stroke increases in opposite directions.

An electromagnet in an active system can be controlled or regulated in such a way that, depending on the wheel stroke of the wheels relative to one another, a corresponding magnetic field is generated which influences the flow properties of the magnetized fluid and thus a corresponding damping coefficient or damping factor depending on the driving situation of the motor vehicle. a corresponding damping force can be set. As a result, a situation-dependent, variable damping force is set which counteracts any swaying or rolling of the motor vehicle. In other words, the damping force is adapted to the situational relative movement of the wheels.

According to a method according to the invention for damping the lift and roll of a motor vehicle, which comprises at least one rigid axle according to the invention, at least one first damper in the area of a first wheel suspension and at least one second damper in the area of a second wheel suspension are connected to one another via a fluid line for guiding a fluid, wherein a damping force for the stroke and roll damping of the motor vehicle is generated by a device arranged in the fluid flow between the dampers for controlling the fluid flow as a function of an opposing wheel stroke of the motor vehicle.

The damping force for damping the lift and roll of the motor vehicle is preferably generated by setting a damping coefficient.

The damping force for damping the lift and roll of the motor vehicle is preferably generated by means of a valve unit as a function of a wheel lift of the motor vehicle in the opposite direction. In other words, a flow of the fluid through the valve unit or through at least one valve of the valve unit is changed, whereby a corresponding damping force is applied counter to the lifting and rolling movement of the motor vehicle.

Alternatively, the damping force for damping the lift and roll of the motor vehicle is generated by means of at least one electromagnet as a function of a wheel lift of the motor vehicle in opposite directions. In other words, the flow properties or the flow behavior of the fluid are changed by the at least one electromagnet, whereby a corresponding damping force is applied counter to the lifting and rolling movement of the motor vehicle.

Different predefined damping forces are preferably set as a function of the wheel stroke of the motor vehicle by means of the device.

The rigid axle according to the invention is preferably used on an axle of a motor vehicle. The motor vehicle can have several axles running transversely to the longitudinal direction of the vehicle, with one, several or all axles in each case being able to be configured as rigid axles according to the invention. A motor vehicle is to be understood as meaning, in particular, a passenger vehicle (passenger car), a commercial vehicle (commercial vehicle) or a heavy goods vehicle (HGV).

• 1 eine stark vereinfachte schematische Ansicht einer erfindungsgemäßen Starrachse für ein Kraftfahrzeug gemäß einer ersten Ausführungsform, und
• 2 eine stark vereinfachte schematische Ansicht der erfindungsgemäßen Starrachse für ein Kraftfahrzeug gemäß einer zweiten Ausführungsform.

Two preferred exemplary embodiments of the invention are explained in more detail below with reference to the figures. Here shows

• 1 a greatly simplified schematic view of a rigid axle according to the invention for a motor vehicle according to a first embodiment, and
• 2 a greatly simplified schematic view of the rigid axle according to the invention for a motor vehicle according to a second embodiment.

According to 1 and 2 a motor vehicle - not shown here - has a rigid axle according to the invention 1 on. It is conceivable that the motor vehicle also has several such rigid axles 1 includes.

The rigid axle shown schematically here 1 includes an axle beam 2 , at the ends of each a wheel suspension 3a , 3b is arranged, wherein on the first wheel suspension 3a two wheels 4a and on the second wheel suspension 3b two more wheels 4b are arranged.

The axle beam 2 includes in the area of the respective wheel suspension 3a , 3b a respective mute 6a , 6b to support a - not shown here - vehicle body of the motor vehicle. The vehicle body is also supported by spring devices - also not shown here. The dampers 6a , 6b are by means of a fluid line 5 , which is provided for guiding a fluid, fluidly connected to one another.

If the motor vehicle has a bump on the left or right side of the vehicle, e.g. For example, if you drive through a pothole, the wheels will travel in opposite directions 4a the left side of the vehicle opposite the wheels 4b the right side of the vehicle. As a result, there is a compression movement of the motor vehicle and an actuation, that is to say a compression or elongation of the dampers 6a , 6b whereby the fluid is in a flowing motion from the one damper 6a , 6b to the other damper 6a , 6b is moved.

One device 7th to control the fluid flow is provided, which generates a damping force for the stroke and roll damping of the motor vehicle as a function of the opposing wheel stroke. In other words, the device represents 7th a damping coefficient, the flow properties of the fluid passing through the device 7th is passed through, influenced to the effect that the damping force acts opposite to the rolling or rolling movement of the motor vehicle. A lifting and rolling movement of the motor vehicle is consequently counteracted or damped by means of the damping force.

After 1 comprises the device 7th according to a first exemplary embodiment, an electromagnet 7b wherein the fluid is a magnetorheological fluid. If the wheel stroke is in opposite directions, a fluid flow is created between the dampers 6a , 6b initiated, the fluid flowing from one side of the motor vehicle to the other with a flow rate that is dependent on the compression movement or the wheel stroke. The electromagnet 7b creates a magnetic field that influences the flow properties of the magnetorheological fluid. Hence, by the magnetic field of the electromagnet 7b a predefined damping coefficient of the fluid is set, which generates a certain damping force. The lifting and rolling movement of the motor vehicle is damped by the damping force, so that the driving comfort and driving safety of the motor vehicle are improved.

In other words, the damping force is only generated as soon as an opposing compression or an opposing wheel stroke occurs and the fluid is thus set in motion and with a certain fluid velocity from one damper to the other 6a , 6b flows. The damping force is then applied in the opposite direction to the rolling or rolling motion of the motor vehicle via the damping coefficient defined by the device. With compression in the same direction or with the wheel stroke in the same direction, that is, when the wheels move 4a , 4b either move all together up or down, the fluid velocity is almost zero, since there is no relative stroke movement of the wheels 4a , 4b takes place to each other and thus the fluid also not from one to the other damper 6a , 6b flows.

Here is the device 7th with the electromagnet 7b designed as an adaptive system, whereby targeted, predefined damping coefficients are provided for generating situation-dependent damping forces

2 shows a second exemplary embodiment, according to which the device 7th a valve unit 7a includes. The dampers 6a , 6b are via the fluid line 5 hydraulically connected to one another, the fluid consequently being a hydraulic oil. The device further comprises 7th a pump 8th and a fluid reservoir 9 . The pump 8th connects the fluid reservoir 9 with the fluid line 5 , with the pump 8th can be controlled by a control unit - not shown here - in order to control the fluid flow within the fluid line 5 to control.

The hydraulic oil is released from the first damper due to the opposing wheel stroke 6a to the second damper 6b or vice versa. The valve unit 7a has the task of influencing the flow properties of the fluid in such a way that a certain damping coefficient is provided as a function of the wheel stroke and a damping force is set as a result in order to implement the stroke and roll damping of the motor vehicle. In other words, the damping coefficient is adapted to the circumstances of the current driving mode of the motor vehicle.

The situational setting of the damping coefficient or the damping force is made by the pump 8th causes additional hydraulic oil from the fluid reservoir as a result of the wheel stroke 9 into the fluid line 5 pumps in order to influence the damping coefficient in a targeted manner and to apply a defined force to the wheels. Thus the device is 7th with the valve unit 7a designed as an active system, whereby an additional force on the wheels can be adapted to the situation in order to react to a changing driving situation.

The invention is not based on the 1 and 2 Embodiments described limited. So can the rigid axle 1 according to 1 instead of an electromagnet 7b also with a valve unit 7a be equipped. The rigid axle can also 1 after 2 instead of a valve unit 7a also with one or more electric motors 7b be equipped to set a damping coefficient or a damping force depending on the situation.

It is also conceivable that the device 7th is set up to set different predefined damping forces as a function of the wheel stroke of the motor vehicle. In other words, the device 7th regardless of whether they have a valve unit 7a or one or more electric motors 7b comprises, be designed as a semi-active system that, depending on the wheel stroke, selects a damping coefficient from several predefined damping coefficients in order to generate a certain damping force depending on the wheel stroke.

List of reference symbols

1

Rigid axle

2

Axle beam

3a

First wheel suspension

3b

Second suspension

4a

First bike

4b

Second wheel

5

Fluid line

6a

First damper

6b

Second damper

7th

contraption

7a

Valve unit

7b

Electromagnet

8th

pump

9

Fluid reservoir

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 202012005687 U1 [0002]

Claims (14)

Rigid axle (1) for a motor vehicle, comprising an axle body (2), at the ends of which a wheel suspension (3a, 3b) for at least indirect fastening of a wheel (4a, 4b) to the axle body (2) is arranged, the axle body (2 ) comprises at least one damper (6a, 6b) for supporting a vehicle body of the motor vehicle in the area of the respective wheel suspension (3a, 3b), characterized by a fluid line (5) for guiding a fluid between the dampers (6a, 6b), wherein a device (7) is provided for controlling the fluid flow in order to generate a damping force for the stroke and roll damping of the motor vehicle as a function of an opposing wheel stroke of the motor vehicle. Rigid axle (1) after Claim 1 , characterized in that the device (7) comprises a valve unit (7a). Rigid axle (1) after Claim 2 , characterized in that the dampers (6a, 6b) are hydraulically connected to one another via the fluid line (5). Rigid axle (1) after Claim 1 , characterized in that the device (7) comprises at least one electromagnet (7b). Rigid axle (1) after Claim 4 , characterized in that the fluid is a magnetorheological fluid. Rigid axle (1) according to one of the preceding claims, characterized in that the device (7) comprises at least one pump (8). Rigid axle (1) according to one of the preceding claims, characterized in that the pump (8) is fluidically connected to at least one fluid reservoir (9). Rigid axle (1) according to one of the preceding claims, characterized in that the device (7) is set up to set different predefined damping forces as a function of the wheel stroke of the motor vehicle. A method for damping the lift and roll of a motor vehicle which has at least one rigid axle (1) according to one of the Claims 1 to 8th comprises, at least one first damper (6a) in the area of a first wheel suspension (3a) and at least one second damper (6b) in the area of a second wheel suspension (3b) being connected to one another via a fluid line (5) for guiding a fluid, whereby through a device (7) arranged in the fluid flow between the dampers (6a, 6b) for controlling the fluid flow as a function of an opposing wheel stroke of the motor vehicle generating a damping force for damping the lift and roll of the motor vehicle. Procedure according to Claim 9 , characterized in that the damping force for the stroke and roll damping of the motor vehicle is generated by setting a damping coefficient. Method according to one of the Claims 9 or 10 , characterized in that the damping force for damping the lift and roll of the motor vehicle is generated by means of a valve unit (7a) as a function of a wheel lift of the motor vehicle in opposite directions. Method according to one of the Claims 9 or 10 , characterized in that the damping force for damping the lift and roll of the motor vehicle is generated by means of at least one electromagnet (7b) as a function of an opposing wheel lift of the motor vehicle. Method according to one of the Claims 9 to 12th , characterized in that by means of the device (7) different predefined damping forces are set as a function of the wheel stroke of the motor vehicle. Motor vehicle, comprising at least one rigid axle (1) according to one of the Claims 1 to 8th .

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