AT526343A4 - Steering force module for a powertrain test bench - Google Patents

Abstract

In order to be able to impress reaction forces on the steering system of the drive train to be tested on a drive train test stand (1), a steering force module (18) is provided which has a force transmission unit (19) with an outer part (19a) and an axis of rotation relative to the outer part (19a). (DA) has a rotatable inner part (19b), wherein the inner part (19b) can be connected in a rotationally fixed manner to a rotatable part of the wheel suspension (4), at least a section of the outer part (19a) being movable in at least one additional degree of freedom of movement relative to the inner part (19b). is, wherein on the movable section of the outer part (19a) an attachment point (BP) is provided for attaching a tie rod end (14a) of the tie rod (14) which is detached from the wheel suspension (4) of the vehicle (2), and wherein the steering force module (18) at least a force generating unit (20) for generating the steering counterforce (FG), the force generating unit (20) having a fixed part (21) and a moving part (22) that is movable relative thereto, the fixed part (21) being at a fixed assembly point (MP) of the Drive train test stand (1) or at a drive train-fixed or vehicle-fixed assembly point (MP ') and the moving part (22) is connected at a connection point (VP) to the movable section of the outer part (19a) of the power transmission unit (19), the steering counterforce ( FG) can be transferred from the at least one force generating unit (20) to the tie rod (14) via the moving part (22) and the movable section of the outer part (19a).

Description

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Steering force module for a powertrain test bench

The invention relates to a steering force module for use on a drive train test bench for a drive train of a vehicle with at least one steerable wheel suspension and a steering system, wherein the steering force module is designed to generate a steering counterforce that counteracts a steering force that can be exerted by the steering system on a tie rod of the steering system. The invention further relates to a drive train test bench, a use of the drive train test bench and a

Method for operating a drive train test bench.

Drive train test benches are well known in the state of the art and are used to carry out test runs with drive trains of mostly multi-track vehicles. Either just the drive train can be set up on the test bench or an entire vehicle with drive train can be set up. In both cases, the original wheels have been removed from the wheel suspensions, leaving only the wheel suspension or at least a part of the wheel suspension relating to the drive

is available.

In order to apply a drive or load torque to the drive train, a number of load machines, for example in the form of asynchronous machines, are provided on the drive train test bench. The available loading machines can be controlled by a control unit in order to carry out desired test runs, e.g. a legally required test run or a desired, definable speed

Torque curve.

The loading machines are arranged in a stationary manner on the test bench, for example bolted to a foundation. The loading machines can be connected to the available wheel suspensions via connecting shafts, usually in a form-fitting manner. For example, the connecting shaft can be connected to a wheel hub of the wheel suspension, which is rotatably mounted in a steering knuckle of the wheel suspension by means of a wheel bearing. If it is a wheel suspension of a driven axle, then the wheel hub can in turn be connected to a drive shaft of the drive train. If necessary, suitable bearing blocks can also be provided between the drive train and the loading machine in order to support the connecting shaft

and/or to support the wheel suspension.

There are also known drive train test benches in which the original wheel is replaced by a special test wheel that stands on the ground so that wheel contact forces take effect. However, the test wheel stands still in the direction of rotation and cannot be steered. The

The connecting shaft of the loading machine can be passed through the test wheel

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and connected to the drive shaft of the drive train. Even those

Drive train test benches are included in the present invention.

If a steerable wheel suspension of a steered axle is connected to a load machine, then the wheel suspension is usually fixed in the neutral position (straight position). This means that no steering movement is possible on the test bench. Steering functions therefore generally cannot be tested on a conventional powertrain test bench. However, it may be desirable to also test certain steering functions on a powertrain test bench. Naturally, however, the test bench does not contain the reaction forces that act on the drive train during real driving on the road, for example a restoring force that occurs at

acts on the steered wheels when cornering.

In order to provide such reaction forces, it is known from WO 2018/046609 A1, for example, that the tie rod of the steering can be unhooked and connected to a separate steering force module. A reaction force can be exerted on the steering via the steering force module. The disadvantage here, however, is that, on the one hand, the kinematics and friction effects of the real wheel suspension cannot be realistically reproduced. On the other hand, due to the mechanically indeterminate coupling between the tie rod and the steering force module, problems can arise due to longitudinal forces (acting essentially normal to the transverse force generated), which can result from movements of the vehicle body, for example, when using a vehicle. The optionally disclosed installation of the steering power module on the underbody of the vehicle is also not included

Any application is easily possible.

It is therefore an object of the invention to provide an improved device or an improved method for reacting reaction forces to the drive train test bench

To be able to memorize the steering system of the drive train to be tested.

According to the invention, the object is achieved with the steering force module mentioned at the outset in that the steering force module has a force transmission unit with an outer part and an inner part which can be rotated about an axis of rotation relative to the outer part, the inner part being rotatably connected to a rotatable part of the wheel suspension, at least a section of the Outer part is movable in at least one additional degree of freedom of movement relative to the inner part, wherein on the movable section of the outer part an attachment point is provided for attaching a tie rod end of the tie rod that is detached from the wheel suspension of the vehicle and wherein the steering force module has at least one force generation unit for generating the steering counterforce, wherein the force generation unit a fixed part and a movable part relative to it

Has a moving part, the fixed part being at a fixed assembly point

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Drive train test bench or at a drive train-fixed or vehicle-fixed assembly point and the moving part is connected at a connection point to the movable section of the outer part of the power transmission unit, the steering counterforce being transferable from the at least one force generating unit via the moving part and the movable section of the outer part to the tie rod. As a result, the steering counterforce can be transferred very precisely to the tie rod and the tie rod end is guided very stable transversely to the direction of the steering counterforce

enabled.

The movable section of the outer part preferably includes the entire outer part.

This can increase stability and simplify the structure.

It is advantageous if the at least one additional degree of freedom of movement has at least one rotational degree of freedom of movement, preferably at least two rotational degrees of freedom of movement, or at least one translational degree of freedom of movement. The at least one rotational degree of freedom of movement can be formed by a swivel joint or a ball joint. At least one

Translational degree of freedom of movement can be formed by a linear guide.

According to an advantageous embodiment, the steering force module comprises a test rim, wherein the movable section of the outer part is connected in an articulated manner to the test rim, with a tire preferably being mounted on the test rim. This means that the steering force module can be used on the drive train test bench mentioned at the beginning, whereby the original test wheel can be replaced by the test rim according to the invention including tires. The execution is

advantageous because the real wheel contact forces take effect here.

According to a preferred embodiment of the invention, the force transmission unit has a swash plate, the inner part of the force transmission unit being formed by an inner ring of the swash plate and the outer part of the force transmission unit being formed by an outer ring of the swash plate, the outer ring being pivotable in a wobbling movement around the inner ring. The outer ring of the swashplate can preferably be connected to the inner ring by means of a self-aligning bearing. This creates a simple and robust design with three rotational degrees of freedom of movement

created. This means that the steering force module can be used very flexibly.

The force generation unit is preferably designed as an active force generation unit, which has at least one electrically controllable actuator, or it is designed as a passive force generation unit, which has at least one suspension unit and/or at least one damping unit. An active force generation unit enables

a very variable and precise generation of the steering counterforce. A passive one

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On the other hand, the force generation unit allows for a very simple design that does not require any

external energy supply required.

The at least one electrically controllable actuator of the active force generation unit preferably comprises a linear actuator, wherein the linear actuator preferably has one of the following actuators: linear motor, pneumatic cylinder, hydraulic cylinder, electric motor with gear. This means that well-known and reliable actuators can be used

Generation of the steering counterforce can be used.

If the force generating unit is designed to be passive, then the suspension device can have a linear, progressive or degressive spring characteristic. Alternatively or additionally, the suspension device can have an adjusting device for changing a suspension characteristic. The suspension device preferably has at least one of the following springs: spiral spring, torsion spring, air spring, rubber spring, gas pressure spring. The damping device can, for example, have an adjusting device for adjusting a damping characteristic. The damping device advantageously has at least one of the following dampers:

Friction damper, hydraulic damper, rubber damper.

Furthermore, the passive force generation unit can advantageously have a compression stage and/or a rebound stage. This allows the desired direction of action of the steering counterforce to be determined. If compression and rebound are provided, then

The steering counterforce can be generated in both directions.

The rotatable part of the wheel suspension, with which the inner part of the power transmission unit can be connected in a rotationally fixed manner, is preferably a drive shaft or a wheel hub.

This enables flexible installation of the steering force module on the wheel suspension.

In order to enable a certain angular compensation, the moving part of the at least one force generating unit is preferably connected in an articulated manner to the movable section of the outer part at the connection point. In the same way, it can be advantageous if the fixed part of the at least one force generating unit can be connected in an articulated manner to the stationary component of the drive train test stand at the assembly point and/or if the attachment point is for the articulated attachment of the tie rod end of the tie rod

is trained.

It is advantageous if a position of the connection point of the moving part on the movable section of the outer part is adjustable and/or if a position of the attachment point for the tie rod head on the movable section of the outer part is adjustable. This makes the steering power module very flexible to suit a wide variety of needs

Drivetrains adaptable.

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The connection point of the moving part and the attachment point for the tie rod head are preferably arranged on opposite end faces of the movable section of the outer part (with respect to the axis of rotation). Alternatively or additionally, the connection point of the moving part and the attachment point for the tie rod end can also be at different locations in the radial direction and/or in the circumferential direction

be arranged with respect to the axis of rotation.

The steering force module according to the invention is preferably used on a drive train test bench for a drive train of a vehicle with at least one steerable wheel suspension, with at least one loading machine for applying a drive or loading torque to a drive shaft of the wheel suspension of the drive train being provided on the drive train test bench and with a control unit for controlling the loading machine is provided. If the steering force module has an active force generation unit, then the control unit is preferably designed to control the at least one actuator of the active force generation unit to generate the steering counterforce. This provides a drive train test bench on which a steering counterforce can be easily applied

can be generated.

The drive train test bench is preferably designed for a drive train of a multi-track vehicle with at least one steered drive axle with two steerable wheel suspensions, the steering force module being provided for at least one of the two steerable wheel suspensions. In order, for example, to generate different steering counterforces, one is preferably used for both steerable wheel suspensions

Steering power module provided.

It can be advantageous if a simulation unit for simulating the steering counterforce is provided on the drive train test bench and the control unit is designed to control the at least one actuator of the active force generation unit depending on a target steering counterforce determined by the simulation unit. This means that a desired steering counterforce can be simulated on the test bench, which is a very good representation

real driving possible.

A detection device for detecting a measured variable representative of an actual steering counterforce can also be provided on the drive train test bench, and the control unit can have a controller which is designed to produce a manipulated variable from the target steering counterforce determined by the simulation unit and the measured variable detected by the detection device determine. The control unit is preferred

designed to connect the at least one actuator of the active force generation unit with the

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to control the determined manipulated variable. This allows a desired steering counter force

be regulated.

The task is further solved with a method according to claim 20.

The present invention is explained in more detail below with reference to Figures 1 to 2b, which are advantageous by way of example, schematically and not in a restrictive manner

Show embodiments of the invention. This shows

Fig.1 shows an exemplary drive train test bench with a built-up

drive train of a vehicle,

Fig.2a shows a steering force module according to the invention in an exemplary embodiment

with an active force generation unit,

Fig.2b shows a section of the steering force module according to the invention in one

exemplary embodiment with a passive force generation unit.

In Fig.1 a schematic drive train test bench 1 is shown in a view from above. The drive train test bench 1 shown is designed for use with a drive train 3 of a two-axle and two-track vehicle 2. For example, only the drive train 3 could be constructed as shown, or the entire vehicle 2 including the drive train 3 could be constructed, as indicated by dashed lines in FIG. Within the scope of the invention, the drive train test stand 1 could of course also be designed to test drive trains 3 with more than two axles or to test a part of a drive train 3, such as a single one

suspension.

The drive train 3 shown in FIG. 1 is designed, for example, as a drive train 3 of a vehicle 2 with a driven front axle VA and front axle steering. The drive train 3 thus has a driven front axle VA with two steerable wheel suspensions 4 and a non-driven rear axle HA with two non-driven and non-steerable wheel suspensions 4. Of course, this is only an example and the drive train 3 could, for example, also have a non-driven front axle VA with steerable wheel suspensions 4 and a driven rear axle HA with non-steerable wheel suspensions 4. Also an all-wheel drive drivetrain 3 as well

All-wheel steering would of course be conceivable.

The drive train 3 here has a drive unit 5, for example an internal combustion engine or electric motor, which drives the driven front axle VA via a suitable transmission 6. A differential gear 7 is also provided on the front axle VA

is connected to the wheel suspensions 4 via drive shafts 8 in order to increase the drive power

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transmitted. The wheel suspensions 4 can, for example, each have a steering knuckle 9, on which a wheel hub (not shown) can be rotated by means of a wheel bearing

is stored.

The drive train 3 also has a steering system 10 for the steered front axle VA. The steering system 10 includes a steering wheel 11, which is connected to a steering gear 13 via a steering linkage 12. The steering gear 13 is in turn connected to the wheel suspensions 4 of the front axle VA via two tie rods 14, in particular with articulation points provided for this purpose on the steering knuckles 9. A steering force FL can be transmitted to the tie rods 14 via the steering system 10, whereby the steering knuckles 9 can be deflected . The design of the drive train 3 is of course only to be understood as an example and is simplified. For example, another steering system 10 would also be possible, which, for example, has no mechanical connection between the steering wheel 11 and the steering gear 12 (so-called steer-by-wire). Within the scope of the invention, the steering system 10 does not necessarily have to have a steering wheel 11 and a steering linkage 12. For example, it could be sufficient if only the steering gear 13 is installed on the test bench. In this case, the steering force FL could e.g. via a (not shown)

Steering actuator of the steering gear 13 are generated.

On the drive train test stand 1, a loading machine 15 is also provided for each wheel suspension 4 for applying a drive or loading torque. The loading machine 15 can, in a known manner, have a suitable electrical machine such as an asynchronous machine. A loading machine 15 can be connected in a rotationally fixed manner to the respective wheel suspension 4 by means of a connecting shaft 16 in order to transmit the torque provided by the loading machines 15 to the drive shafts 8 of the wheel suspension 4. The connecting shafts 16 can be connected, preferably in a form-fitting manner, to the wheel suspensions 4, in particular to the wheel hub, for example via a screw flange. The wheel hubs are connected to the drive shaft 8 on the inside facing away from the connecting shaft. If necessary, suitable bearing blocks can also be provided

be to support the connecting shaft 16 or the wheel suspension 4.

If the drive train test bench mentioned at the beginning is used with test wheels, then the test wheel can be replaced, for example, by a test wheel PR according to the invention, which is indicated by dashed lines in FIG. 2a and will be described in more detail below.

This means that the wheel contact force can continue to have a realistic effect.

A control unit 17 is also provided on the drive train test stand 1, which is designed to control the loading machines 11 to carry out a test run.

The control unit 17 can have suitable hardware and/or software. Over

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The control unit 17 can specify a desired test run in order to simulate certain driving states of the drive train 3. The test run can, for example, be specified in the form of a time course of setpoint values SW, e.g. setpoint speed or setpoint torque. A suitable control device can also be provided to regulate the setpoint values SW. The test run can be used to simulate desired resistances that act on the drive train 3 during real driving,

for example, slopes or slopes of a road or twists.

Depending on the steering movement of the steering wheel 11, a certain steering force is generated, which acts via the tie rods 14 on the steering knuckles 9 of the wheel suspensions 4 of the front axle VA. Normally the steering knuckles 9 would be deflected at a certain steering angle. As was mentioned at the beginning, however, such a deflection is generally not possible on the drive train test bench 1, since the wheel suspensions 4 are connected to the stationary load machines 15 via the connecting shafts 16. But even if a deflection of the wheel suspensions 4 were possible on the drive train test bench 1, any reaction forces that would normally arise during real driving on the road due to the driving conditions would be missing. It follows that even if the wheel suspensions 4 could be deflected, the steering force generated would not be counteracted by any counterforce or a steering counterforce that does not correspond to reality. In order to be able to exert a desired steering counterforce on the steering system 10 despite these restrictions on the drive train test bench 1, according to the invention there is a steering force module 18 (not shown in FIG. 1).

provided, which is described in detail below with reference to Fig. 2a + 2b.

Fig. 2a shows a section of the drive train test bench 1 in the area of the left front wheel suspension 4. The loading machine 15 and part of the connecting shaft 16 are shown cut off. A part of the drive shaft 8 of the drive train 3 and a part of the steering gear 13 are also shown cut off. A steering force module 18 according to the invention is provided on the wheel suspension 4 in an exemplary embodiment. The steering force module 18 is designed to generate a steering counterforce FG that counteracts the steering force FL that can be exerted on a tie rod 14 by the steering system 10. The steering force module 18 has a force transmission unit 19 with an outer part 19a and an inner part 19b which is rotatable relative to the outer part 19a about an axis of rotation DA. The inner part 19b is connected in a rotationally fixed manner to a rotatable part of a wheel suspension 4 and can rotate with it, while the outer part 19a is stationary (in the direction of rotation).

In the example shown, the original steering knuckle 9 including the wheel hub of the wheel suspension 4 is removed and replaced by the power transmission unit 19. The inner part 19b thus replaces

essentially the wheel hub. The inner part 19b is connected to the axial end face

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Connecting shaft 16 of the loading unit 15 is connected and connected to the drive shaft 8 on the opposite end face. The connecting shaft 16 can, for example, be screwed to the inner part 19b via a suitable flange 16b. The drive shaft 8 can be connected to the inner part 19b via a suitable shaft-hub connection, for example via a toothing. Of course, the embodiment shown is only an example and the inner part 19b could, for example, also be connected directly to the drive shaft 8 or the original wheel hub, so that if necessary only the steering knuckle 9 has to be removed and the original wheel hub can continue to be used

can.

At least a portion of the outer part 19a is movable relative to the inner part 19b in at least one additional degree of freedom of movement (in addition to rotation about the rotation axis DA). This at least one additional degree of freedom of movement can, for example, have at least one rotational degree of freedom of movement or at least one translational degree of freedom of movement. The at least one rotational degree of freedom of movement can be realized, for example, by a swivel joint or a ball joint. The at least one translational degree of freedom of movement can be realized, for example, by a linear guide. The at least one additional degree of freedom of movement is chosen so that the movable section of the

Outer part 19a can follow a deflection of the tie rod 14.

In the example shown, the movable section of the outer part 19a includes the entire outer part 19a and the at least one additional degree of freedom of movement includes two rotational degrees of freedom of movement. The force transmission unit 19 is thus designed as a type of swash plate, with the inner part 19b of the force transmission unit 19 being formed by an inner ring of the swash plate and the outer part 19a of the force transmission unit 19 being formed by an outer ring of the swash plate. The outer ring 19a can thus be pivoted in a wobbling movement around the inner ring 19b. The outer ring 19a therefore has a first rotational degree of freedom of movement relative to the inner ring 19b, in that the inner ring 19b is rotatable about the axis of rotation DA relative to the outer ring 19a. The axis of rotation DA also corresponds to the common axis of rotation of the connecting shaft 16 and the drive shaft 8 and runs here in the X direction. The second rotational degree of freedom of movement corresponds to a rotation of the outer ring 19a about the Y axis and the third second rotational degree of freedom of movement corresponds to a rotation of the outer ring 19a about the Z axis. This results in the outer ring 19a being around one

Pivot point DP can be rotated around all three axes X, Y, Z.

In order to realize the three degrees of freedom of movement mentioned, the outer ring 19a can be connected to the inner ring 19b, for example by means of a self-aligning bearing 26. The

Self-aligning bearing 26 can be, for example, a self-aligning ball bearing or a spherical roller bearing, such as

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is shown as an example in Fig.2. While unrestricted rotation around the X axis is possible, the other two rotational degrees of freedom of movement are restricted, so only a limited deflection angle is possible. It should be noted that the second and third rotational degrees of freedom of movement in this embodiment are not limited to rotation about the Y-axis and rotation about the Z-axis, but essentially rotation about any axis in the Y-Z plane is possible , analogous to one

Ball joint.

According to an alternative embodiment (not shown), the second and third rotational degrees of freedom of movement could also be realized, for example, by a universal joint. For this purpose, the outer ring 19a could be connected to an intermediate ring, for example via a first swivel joint, and the intermediate ring could be connected to the inner ring 19b via a second swivel joint, with the axes of rotation of the two swivel joints being normal to one another. For example, the axis of rotation of the first swivel joint could run in the Y direction and the axis of rotation of the second swivel joint could run in the Z direction.

Direction. In this case the rotation would be limited to the Y-axis and Z-axis.

On the movable section of the outer part 19a, an attachment point BP is also provided for attaching a tie rod end 14a of the tie rod 14 that is detached from the wheel suspension 4. In the example shown, the outer ring of the swashplate forms the movable section of the outer part 19a. The attachment point BP is located on an end face facing the tie rod 14 with respect to the axis of rotation DA

outer ring.

In the case of the drive train test bench with test wheels mentioned at the beginning, the original test wheel could, as already mentioned, be replaced by a test wheel PR according to the invention, as indicated by dashed lines in Fig. 2a. The test wheel PR according to the invention can have a special test rim PF, in which the power transmission unit 19 is integrated. The movable outer part 19a of the force transmission unit 19 is connected to the test rim PF in an articulated manner, for example by means of a suitable bearing 27. As a result, the outer part 19a can be pivoted relative to the inner part 19b on the one hand and relative to the test rim PF on the other hand. A tire R is preferably arranged on the test rim PF, via which the test wheel PR is supported on the floor of the test stand. As described at the beginning, the connecting shaft 16 in this version is centrally located through the test rim

passed through and connected to the drive shaft 8.

The bearing 27 is only indicated schematically in FIG. 2a and can be designed, for example, as a joint bearing. When the test stand 1 is in operation, the test rim PF (including tire R) is stationary and the connecting shaft 16 and the drive shaft 8 rotate relative to the

Test rim PF and also relative to the movable outer part 19a of the power transmission unit

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19. In the event of a steering angle as a result of a steering force FL, the outer part 19a can also

can be pivoted relative to the test rim PF and relative to the inner part 19b.

The steering force module 18 further has at least one force generating unit 20 for generating the steering counterforce FG. The force generating unit 20 has a fixed part 21 and a moving part 22 that is movable relative thereto. The fixed part 21 is here connected to a stationary assembly point MP of the drive train test bench 1. The stationary assembly point MP of the drive train test bench 1 can, for example, be arranged on a dedicated console of a suitable stationary structure of the drive train test bench 1. The connection is preferably designed to be detachable, for example by a screw connection. A variable position of the stationary assembly point MP on the drive train test stand 1 can also be advantageous in order to be able to change the position of the fixed part 21. To use the steering force module 18 during a test run, the fixed part

21 in any case fixed in place again, e.g. by tightening the screws.

The moving part 22 of the force generating unit 20 is connected at a connection point VP to the movable section of the outer part 19a, which is formed here by the outer ring of the swash plate. In the example shown, the connection point VP lies with respect to the axis of rotation DA on an end face of the movable section of the outer part 19a, here the outer ring of the swash plate, opposite the attachment point BP for the tie rod head 14a. The steering counterforce FG generated by the at least one force generating unit 20 can thus be transmitted to the tie rod 14 via the moving part 22 and the movable section of the outer part 19a, so that the steering counterforce FG counteracts the steering force FL transmitted from the steering system 10 to the tie rod 14. Contrary to the illustrated embodiment, the connection point VP of the moving part 22 and the attachment point BP for the tie rod head 14a could of course also be at different locations in the radial direction and / or in the circumferential direction with respect to the axis of rotation DA or the pivot point DP

be arranged.

Alternatively, the fixed part 21 could also be connected to a mounting point MP' of the drive train 3 that is fixed to the drive train or to a mounting point MP' that is fixed to the vehicle if an entire vehicle 2 is used as a test specimen. The assembly point MP' could, for example, be arranged at a suitable position on the underbody of a body of the vehicle 2 and the fixed part 21 of the force generating unit 20 (indicated by dashed lines) could, for example, be screwed to the underbody. In the example shown, the connection point VP 'could also be arranged on the same end face of the outer ring as the attachment point BP for the tie rod 14, for example diametrically opposite the attachment point BP with respect to the axis of rotation DA. A radial distance between the connection point VP' and the axis of rotation DA or the pivot point DP

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In this case, it could serve as a lever arm for transmitting the steering counter force FG to the

Tie rod 14 serves.

In Fig. 2a, the at least one force generation unit 20 is designed as an active force generation unit and includes an electrically controllable actuator. The actuator is designed here in particular as a linear actuator, the moving part 22 of which can be moved translationally relative to the fixed part 21. The linear actuator can include, for example, an electric linear motor, a pneumatic cylinder, a hydraulic cylinder or an electric motor with a gear (servo motor). In principle, however, other suitable actuators would also be conceivable, for example a rotary electric motor that acts via a lever arm as a moving part 22 that acts on the connection point VP. To generate the steering counterforce, the actuator can be controlled by a control unit, in particular by the

Control unit 17 of the test stand 1, as will be described below.

According to an alternative embodiment shown in FIG. 2b, the force generating unit 20 can also be designed as a passive force generating unit and have at least one suspension unit F and/or at least one damping unit D. In the embodiment shown, the passive force generating unit 20 has both a suspension unit F and a damping unit D, merely as an example. The suspension unit F and the damping unit D are shown schematically and can be designed in a suitable manner to generate the desired steering counterforce FG. In contrast to the active force generation unit 20 (Fig. 2a), no control by a control unit is necessary in the passive force generation unit 20 (Fig. 2b), but the steering counterforce FG is essentially a reaction force that results from the

constructive design of the suspension unit F or the damping unit D results.

The suspension device F can, for example, have a linear, a progressive or a degressive spring characteristic. Alternatively or additionally, the suspension device F could also have an adjusting device (not shown) for changing a suspension characteristic. The suspension device F can essentially have any suitable spring, for example at least one of the following types of springs: spiral spring, torsion spring, air spring, rubber spring, gas pressure spring. The damping device D can also have an adjusting device for adjusting a damping characteristic. The damping device D can also have any suitable damper, for example one of the following dampers: friction damper, hydraulic damper, rubber damper. Furthermore, it can be advantageous if the passive force generation unit has a compression stage and/or a rebound stage, preferably both. This allows the steering counterforce to be generated in both directions, i.e. both when turning to the left and when turning to the left

on the right, of course at different heights if necessary.

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It can also be advantageous if the moving part 22 of the at least one force generating unit 20 is connected in an articulated manner to the movable section of the outer part 19a at the connection point VP. A detachable connection of the moving part 22 to the movable section of the outer part 19a would also be conceivable in order to simplify the assembly of the steering force module 18 on the test bench. Alternatively or additionally, the fixed part 21 of the at least one force generating unit 20 can also be connected or connectable in an articulated manner to the stationary component of the drive train test bench 1 at the assembly point MP. In the same way, the attachment point BP can also be designed for the articulated attachment of the tie rod head 14a of the tie rod 14. The person skilled in the art can select a suitable structural design of the articulated connection, e.g. swivel joint, ball joint or the like. It can also be advantageous if a position of the connection point VP of the moving part 22 on the movable section of the outer part 19a is adjustable and / or if a position of the attachment point BP for the

Tie rod head 14a is adjustable on the movable section of the outer part 19a.

If the force generation unit is designed as an active force generation unit, as shown for example in Fig. 2a, then the control unit 17 is preferably designed not only to control the loading machines 15 (and any other functions of the test bench), but also to control the at least one actuator the active force generation unit to generate the steering counterforce FG. Of course, a separate control unit (not shown) could also be provided for controlling the at least one actuator of the active force generation unit, which can be part of the steering force module 18, for example. As a result, the steering force module 18 could, for example, be operated independently of the remaining functions of the drive train test bench 1. The separate control unit could also be connected to the control unit 17 of the drive train test bench 1 via a suitable communication connection, so that the steering counterforce FG via the control unit 17 of the

Drive train test bench 1 can be controlled.

A simulation unit 23 can also be provided for simulating the steering counterforce FG and the control unit 17 can be designed to control the at least one actuator of the active force generation unit depending on a target steering counterforce FG_soll determined by the simulation unit 23. Advantageously, a detection device 24 can also be provided for detecting a measured variable M representative of an actual steering counterforce FG_ist and the control unit 17 can have a controller 25 which is designed to use the target steering counterforce FG_soll determined by the simulation unit 23 and the to determine a manipulated variable X recorded by the detection device 24. The control unit 23 can then

at least one actuator of the active force generation unit with the determined manipulated variable X

14 153”

15

20

25

30

35

AV-4344 AT

head for. As a result, a control loop for regulating a specific steering counterforce FG can be implemented. Any suitable controller can be used as controller 25,

for example PL controller or PID controller, etc.

Even if only one steering force module 18 for a wheel suspension 4 of the drive train 3 is shown in FIG. 2a, a second, preferably identically designed, steering force module 18 could of course also be provided for the right wheel suspension (not shown) of the front axle VA. In this case, the right tie rod 14 of the steering gear 13 would be connected to the attachment point BP of the second (not shown) steering force module 18. As a result, a steering counterforce FG can be exerted on the steering system 10 on both sides. If necessary, different steering counterforces FG can of course be generated on both sides, for example at the same time, in order to achieve this

To be able to replicate reality as best as possible.

In principle, however, it could also be sufficient if only one steering force module 18 is provided for a steered axle of the drive train 3. In the example shown in Fig. 2a, the (not shown) tie rod 14 of the right front wheel suspension 4 could, for example, only be detached from the steering knuckle 9 and remain in the detached state. In this case, the common steering counter force FG for both sides could only come from

Steering force module 18 on the left side are generated.

Finally, an advantageous use of the steering force module 18 on the drive train test bench 1 to carry out a test run will be explained below. For the sake of simplicity, the description is only given for one wheel suspension 4 and can of course be carried out in an analogous manner for other wheel suspensions 4. The steps don't have to be either

must be carried out in the specified order.

First, a drive train 3 with at least one steerable wheel suspension 4 and with a steering system 10 (or an entire vehicle 2 with drive train 3) is set up in a suitable manner on the test bench 1. The tie rod head 14a of the tie rod 14 of the steering gear 13 of the steering system 10 is then detached from the wheel suspension 4, in particular from the steering knuckle 9, and the steering knuckle 9, possibly including the rotatable wheel hub, is removed from the wheel suspension 4. The inner part 19b of the power transmission unit 19 of the steering power module 18 is then connected in a rotationally fixed manner to a rotatable part of the wheel suspension 4 and the loading machine 15 is directly connected via the connecting shaft 16

or indirectly connected to the drive shaft 8 of the wheel suspension 4.

The rotatable part of the wheel suspension 4 can, for example, be the drive shaft 8 itself, as shown in FIG. 2, but could also be the wheel hub if this has not been removed with the steering knuckle 9. The direct connection of the connecting shaft 16

with the drive shaft 8 can mean that the connecting shaft 16 directly, i.e

15

20

25

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AV-4344 AT

is connected to the drive shaft 8 without any intermediate component, e.g. via a suitable shaft/hub connection such as a toothing. Indirect connection can mean that the connecting shaft 16 is indirectly connected to the drive shaft 8 via a component, for example the wheel hub, for example if only the steering knuckle 9 has been removed and the wheel hub remains on the wheel suspension 4. Indirectly can also mean that the wheel hub is replaced by the inner part 19b of the power transmission unit 19 and the connecting shaft 16 is connected to the inner part 19b on an axial end face of the inner part 19b and the drive shaft 8 is connected to the opposite end face

is, as shown in Fig.2.

As soon as the power transmission unit 19 is mounted, the fixed part 21 of the force generation unit 20 of the steering force module 18 can be connected to a stationary mounting point MP of the drive train test bench 1 or to a drive train-fixed mounting point MP 'of the drive train 3 or vehicle-fixed mounting point MP' of the vehicle. Of course, the fixed part 21 could also be pre-assembled if necessary. Finally, the previously detached tie rod end 14a of the tie rod 14 is attached to the attachment point BP of the movable portion of the outer part 19a of the power transmission unit 19 (e.g. the outer ring of the swash plate). This completes the construction and...

Test run can begin.

To carry out a test run, a drive or loading torque can be transmitted to the drive shaft 8 with the loading machine 15. With the steering system 10 of the drive train 3 (e.g. via the steering wheel 11) a steering force FL can then be exerted on the tie rod 14 and with the at least one (passive or active) force generating unit 20 of the steering force module 18 a steering counterforce FG can be generated, which corresponds to the steering force FL counteracts. If an active force generation unit is used, then both the loading machine 15 and the actuator of the active force generation unit can be controlled, for example, via the central control unit 17 of the drive train test bench 1. If only the drive train 3 (i.e. without a vehicle and without a steering wheel 11) is used as the test specimen, then the steering force FL can also be generated, for example, via any existing steering actuator (not shown) of the steering system 10, in particular of the steering gear 13. The steering actuator can, for example, be part of a power steering system and, for example, also via the

Control unit 17 can be controlled.

16/53”

Claims (25)

15 20 25 30 35 AV-4344 AT patent claims 1. Steering force module (18) for use on a drive train test bench (1) for a drive train (3) of a vehicle (2) with at least one steerable wheel suspension (4) and a steering system (10), the steering force module (18) being designed to to generate a steering force (FL) that counteracts a steering force (FL) that can be exerted by the steering system (10) on a tie rod (14) of the steering system (10), characterized in that the steering force module (18) has a force transmission unit (19) with an external part (19a) and an inner part (19b) which is rotatable relative to the outer part (19a) about an axis of rotation (DA), the inner part (19b) being rotatably connected to a rotatable part of the wheel suspension (4), at least a section of the outer part ( 19a) is movable in at least one additional degree of freedom of movement relative to the inner part (19b), wherein on the movable section of the outer part (19a) there is an attachment point (BP) for attaching a tie rod end (14a) detached from the wheel suspension (4) of the vehicle (2). Tie rod (14) is provided and wherein the steering force module (18) has at least one force generating unit (20) for generating the steering counter force (FG), the force generating unit (20) having a fixed part (21) and a moving part (22) movable relative thereto, wherein the fixed part (21) can be fastened to a stationary assembly point (MP) of the drive train test bench (1) or to a drive train-fixed or vehicle-fixed assembly point (MP') and the moving part (22) is at a connection point (VP) with the movable section of the outer part ( 19a) of the force transmission unit (19), the steering counterforce (FG) being generated by the at least one force generating unit (20) via the moving part (22) and the movable section of the Outer part (19a) can be transferred to the tie rod (14). 2. Steering force module (18) according to claim 1, characterized in that the movable section of the outer part (19a) comprises the entire outer part (19a). 3. Steering force module (18) according to claim 1 or 2, characterized in that the at least one additional degree of freedom of movement has at least one rotational degree of freedom of movement, preferably at least two rotational degrees of freedom of movement, or at least has a translational degree of freedom of movement. 4. Steering force module (18) according to claim 3, characterized in that the at least one rotational degree of freedom of movement is formed by a swivel joint or by a ball joint or that the at least one translational degree of freedom of movement is formed by a linear guide is formed. 5. Steering force module (18) according to one of claims 1 to 4, characterized in that the steering force module (18) comprises a test rim (PF), the movable section 17158” 15 20 25 30 35 AV-4344 AT of the outer part (19a) is articulated to the test rim (PF), whereby on the test rim (PF) preferably a tire (R) is mounted. 6. Steering force module (18) according to one of claims 1 to 5, characterized in that the force transmission unit (19) has a swash plate, the inner part (19b) of the force transmission unit (19) being formed by an inner ring of the swash plate and the outer part (19a ) of the power transmission unit (19) is formed by an outer ring of the swashplate, the outer ring being in a Tumbling movement can be pivoted around the inner ring. 7. Steering force module (18) according to claim 6, characterized in that the outer ring the swashplate is connected to the inner ring by means of a self-aligning bearing (26). 8. Steering force module (18) according to one of claims 1 to 7, characterized in that the force generation unit (20) is designed as an active force generation unit which has at least one electrically controllable actuator or that the force generation unit (20) is designed as a passive force generation unit, which at least one suspension unit (F) and/or at least one damping unit (D) having. 9. Steering force module (18) according to claim 8, characterized in that the at least one electrically controllable actuator comprises a linear actuator, the linear actuator preferably having one of the following actuators: linear motor, Pneumatic cylinder, hydraulic cylinder, electric motor with gearbox. 10. Steering force module (18) according to claim 8, characterized in that the suspension device (F) has a linear, a progressive or a degressive spring characteristic and / or that the suspension device (F) has an adjusting device for changing a suspension characteristic and / or that Suspension device (F) has at least one of the following springs: spiral spring, torsion spring, air spring, rubber spring, gas pressure spring and/or that the damping device (D) has an adjusting device for adjusting a damping characteristic and/or that the damping device (D) has at least one of the following dampers has: friction damper, hydraulic damper, rubber damper and/or that the passive force generation unit has a pressure stage and/or has a rebound stage. 11. Steering force module (18) according to one of claims 1 to 10, characterized in that the rotatable part of the wheel suspension (4) is a drive shaft (8) or a wheel hub. 12. Steering force module (18) according to one of claims 1 to 11, characterized in that the moving part (22) of the at least one force generating unit (20) on 15 20 25 30 35 AV-4344 AT Connection point (VP) is articulated to the movable section of the outer part (19a) and / or that the fixed part (21) of the at least one force generating unit (20) at the assembly point (MP, MP ') is articulated to the stationary component of the drive train test bench (1) can be connected and/or that the attachment point (BP) is used articulated fastening of the tie rod head (14a) of the tie rod (14) is formed. 13. Steering force module (18) according to one of claims 1 to 12, characterized in that a position of the connection point (VP) of the moving part (22) on the movable section of the outer part (19a) is adjustable and / or that a position of the attachment point (BP ) for the tie rod end (14a) on the movable section of the Outer part (19a) is adjustable. 14. Steering force module (18) according to one of claims 1 to 13, characterized in that the connection point (VP) of the moving part (22) and the attachment point (BP) for the tie rod end (14a) are on opposite sides with respect to the axis of rotation (DA). End faces of the movable section of the outer part (19a) are arranged and/or that the connection point (VP) of the movable part (22) and the attachment point (BP) for the tie rod end (14a) are at different locations in the radial direction and/or in Circumferential direction with respect to the axis of rotation (DA) are arranged. 15. Drive train test stand (1) for a drive train (3) of a vehicle (2) with at least one steerable wheel suspension (4), at least one loading machine (15) on the drive train test stand (1) for applying a drive or loading torque to a drive shaft (8 ) the wheel suspension (4) of the drive train (3) is provided and a control unit (17) is provided for controlling the loading machine (16), characterized in that at least one steering force module (18) according to one of claims 1 to 14 is provided, wherein the control unit (17) in the case of an active force generation unit is preferably designed to provide the at least one actuator of the active force generation unit To control the generation of the steering counterforce (FG). 16. Drive train test bench (1) according to claim 15, characterized in that the drive train test bench (1) is designed for a drive train (3) of a multi-track vehicle (2) with at least one steered drive axle (VA) with two steerable wheel suspensions (4), whereby the steering force module (18) is provided for at least one of the two steerable wheel suspensions (4), preferably a steering force module (18) according to one of claims 1 to 14 for both steerable wheel suspensions (4). is provided. 17. Drive train test bench (1) according to claim 15 or 16, characterized in that a simulation unit (23) is provided for simulating the steering counterforce (FG). 19/53” 15 20 25 30 35 AV-4344 AT and that the control unit (17) is designed to control the at least one actuator of the active force generation unit depending on one of the simulation unit (23). to control the determined target steering counter force (FG_soll). 18. Drive train test bench (1) according to claim 17, characterized in that a detection device (24) is provided for detecting a measured variable (M) representative of an actual steering counter force (FG_act), and that the control unit (17) has a controller (25). , which is designed to determine a manipulated variable (X) from the target steering counterforce (FG_soll) determined by the simulation unit (23) and the measured variable (M) recorded by the detection device (24) and that the control unit (17) is designed for this purpose is, the at least one actuator of the active force generation unit with the determined manipulated variable (X). 19. Use of the drive train test bench (1) according to one of claims 15 to 18 for carrying out a test run with a drive train (3) of a vehicle (2) with at least one steerable wheel suspension (4) and a steering system (10), wherein a tie rod end (14a ) a tie rod (14) of the steering system (10) is detached from the wheel suspension (4), the at least one loading machine (15) being connected directly or indirectly to a drive shaft (8) of the wheel suspension (4) via a connecting shaft (16). , wherein the inner part (19b) of the force transmission unit (19) of the steering force module (18) is connected in a rotationally fixed manner to a rotatable part of the wheel suspension (4), the fixed part (21) of the at least one force generating unit (20) of the steering force module (18) being connected to a fixed mounting point (MP) of the drive train test bench (1) or with a drive train-fixed or vehicle-fixed mounting point (MP '), the tie rod head (14a) of the tie rod (14) being at the attachment point (BP) of the movable section of the outer part (19a) of the power transmission unit (19) is attached, with the loading machine (15) transmitting a drive or loading torque to the drive shaft (8), with the steering system (10) exerting a steering force (FL) on the tie rod (14) and with The at least one force generating unit (20) of the steering force module (18) generates a steering counterforce (FG), which counteracts the steering force (FL). 20. Method for carrying out a test run on a drive train test bench (1) with a drive train (3) of a vehicle (2) which has at least one steerable wheel suspension (4) and a steering system (10), wherein a tie rod end (14a) of the steering system ( 10) is released from the steerable wheel suspension (4), wherein an inner part (19b) of a power transmission unit (19), which is rotatable about an axis of rotation (DA) relative to an outer part (19a) of the power transmission unit (19), with a rotatable part the wheel suspension (4) is connected in a rotationally fixed manner, with the tie rod end (14a) on one Attachment point (BP) of a, in at least one additional degree of freedom of movement 20/28” 15 20 25 AV-4344 AT A section of the outer part (19a) of the power transmission unit (19) which is movable relative to the inner part (19b), a fixed part (21) of a force generating unit (20) being connected to a stationary mounting point (MP) of the drive train test bench (1) or to a drive train fixed or vehicle-fixed mounting point (MP') is connected and a moving part (22) of the power generation unit (20) is connected to the movable section of the outer part (19a) of the power transmission unit (19), wherein a loading machine (15) of the drive train test bench (1) via a connecting shaft (16) is connected directly or indirectly to a drive shaft (8) of the wheel suspension (4), with the loading machine (15) transmitting a drive or loading torque to the drive shaft (8), with the steering system (10) generating a steering force (FL ) is exerted on the tie rod (14) and with the at least one force generating unit (20) a steering counterforce (FG) is generated, which counteracts the steering force (FL) via the moving part (22) and the movable section of the outer part (19a). the tie rod (14) acts, preferably a steering knuckle (9) of the wheel suspension (4) with a wheel hub mounted therein being replaced by the power transmission unit (19), the inner part (19b) of the power transmission unit (19) rotationally fixing the connecting shaft (16). connects to the drive shaft (8) or a steering knuckle (9) of the wheel suspension (4) is replaced by the power transmission unit (19) without a wheel hub mounted therein, the wheel hub connecting the connecting shaft (16) in a rotationally fixed manner to the drive shaft (8) and the Inner part (19b) of the power transmission unit (19) is connected to the wheel hub or to the drive shaft (8). becomes. 21/23”