Device for connecting trailer and / or load-bearing unit

Abstract

The invention relates to a method and to a device for operating a device for connecting a trailer and / or a load-bearing unit, which device can be assembled to the rear of a motor vehicle body, comprising a retaining arm which is rigidly connected to the motor vehicle body at a first end during operation, a connecting element for the trailer and / or the load-bearing unit is supported on the second end, a force acting on the connecting element during operation and transmitted by the retaining arm to the motor vehicle body is detected by the evaluation unit by means of a deformation sensor, and the retaining arm has at least two deformation regions, when a force acts on the retaining arm, the deformation behavior of the deformation region is detected by at least one deformation sensor, which is rigidly connected to the corresponding deformation region of the retaining arm, such that the deformation behavior thereof is detected.

Description

Summary of the invention

[0001] The present invention relates to a method for operating a device for connecting a trailer and / or a load-bearing unit that can be assembled at the rear of a motor vehicle body, the device comprising a retaining arm, which is fixedly connected to the motor vehicle body at a first end during operation and carries a connecting element for the trailer and / or the load-bearing unit at a second end, wherein a force applied to the connecting element during operation and transmitted by the retaining arm to the motor vehicle body is detected by an evaluation and analysis unit with the aid of a deformation sensor, wherein the retaining arm has at least two deformation areas, and when a force acts on the retaining arm, the deformation behavior of the deformation area is respectively detected by at least one deformation sensor, which is rigidly connected to the corresponding deformation area of ​​the retaining arm, thereby detecting the deformation behavior of the deformation area, and is characterized in that the evaluation and analysis unit has a load analysis stage, which, starting from the deformation values ​​of the at least two deformation areas obtained by the deformation sensor, uses an analysis method to obtain at least one load type of the retaining arm.

[0002] The advantage of the solution according to the invention is therefore that there is a way to analyze the type of loading of the holding arm and to differentiate between the types of loading in order to be able to provide information on the influence of the loading of the connecting element on the vehicle, for example.

[0003] It is particularly advantageous if the load analysis stage uses the deformation values ​​without converting them into forces in the vertical direction and / or in the longitudinal direction of the vehicle and / or transversely to the longitudinal midplane of the vehicle.

[0004] An advantageous solution provides that at least one evaluation method is a value comparison method, ie a method which evaluates different determined or stored deformation values ​​by comparison with other values.

[0005] It is particularly advantageous if the value comparison method compares the deformation values ​​with one another and / or with reference values ​​in order to thereby detect whether the deformation values ​​meet different evaluation criteria.

[0006] It is particularly advantageously provided that the reference value is a reference value which is predefined, in particular stored, in the load analysis stage.

[0007] In principle, the reference value can be determined theoretically or by model calculations.

[0008] However, it is particularly advantageous if the reference value is determined experimentally.

[0009] It is particularly advantageous here if the reference value is determined by load tests on representative holding arms.

[0010] A wide variety of approaches are conceivable with regard to the implementation of the analytical method.

[0011] An advantageous solution provides that at least one of the evaluation methods evaluates the absolute value of the load-dependent deformation value.

[0012] The load-dependent deformation value refers to the deformation value detected by the deformation sensor when the holding arm is loaded. In certain cases, it is considered necessary to correct the deformation value detected by the unloaded detection unit when the holding arm is unloaded.

[0013] For example, the evaluation criterion is based on a comparison of the absolute value of the load-dependent deformation value with a threshold value as a reference value.

[0014] A further advantageous solution provides that at least one further evaluation criterion is based on a comparison of each of the absolute values ​​of the load-dependent deformation values ​​with a stored reference value range.

[0015] In this case, however, the stored reference value range is also either determined theoretically or preferably determined experimentally, in particular also by load tests of representative holding arms.

[0016] A further advantageous solution provides that at least one evaluation criterion compares at least one deformation value of a deformation region with a deformation value of at least one further deformation region.

[0017] Such an analysis method makes a comparison, in particular, of the behavior of deformation values ​​of deformation regions that are highly sensitive to the support load in relation to deformation regions that are less sensitive to the support load.

[0018] The method according to the invention can be implemented particularly advantageously if the evaluation criterion is based on a comparison of the behavior of at least one of the deformation values ​​of a deformation region that is highly sensitive to support loads relative to at least one of the deformation values ​​of a deformation region that is less sensitive to support loads.

[0019] From this comparison, conclusions can be drawn in a wide variety of other analytical methods.

[0020] A simple solution provides that the analytical method determines the difference between two deformation values.

[0021] This difference between two deformation values ​​can in principle be compared with a predefined reference value range.

[0022] However, it is particularly advantageous if the evaluation method determines the ratio of the difference between two deformation values ​​to the maximum of the two deformation values.

[0023] This ratio can also be compared, for example, with a certain reference value.

[0024] It is particularly advantageous if the evaluation criterion is based on the ratio of the difference between two deformation values ​​to the maximum value of the deformation values ​​compared to a stored reference value range.

[0025] Each of the aforementioned evaluation criteria allows, for example, a simple differentiation between the fact that a trailer is connected to the connecting element or the fact that a load carrier, in particular a bicycle carrier, is connected to the connecting element.

[0026] Thus, for example, when a trailer is present, the load-dependent deformation value or the load-dependent deformation value of the deformation region highly sensitive to the support load is above the threshold value, and the load-dependent deformation value or the load-dependent deformation value of the deformation region less sensitive to the support load is below the threshold value.

[0027] In contrast, if a bicycle carrier is present, the load-dependent deformation value or the load-dependent deformation values ​​of both deformation regions are above the threshold value.

[0028] Furthermore, when a trailer is present, the load-dependent deformation values ​​or the load-dependent deformation values ​​of the deformation region with low sensitivity to the support load are within a reference value range including the deformation value zero, while the load-dependent deformation values ​​or the load-dependent deformation values ​​of the deformation region with high sensitivity to the support load are outside the reference value range.

[0029] In addition, when a trailer is present, the ratio of the difference between the load-dependent deformation values ​​of a deformation region that is highly sensitive to support load and a deformation region that is less sensitive to support load to the maximum deformation value is within a reference value range and is higher than the value when a bicycle carrier is present. When a bicycle carrier is present, the reference value range for this ratio is below the reference value range for a trailer.

[0030] A further advantageous method provides that the evaluation method determines the magnitude of at least one force acting on the deformation region by comparing the respective load-dependent deformation value with at least one load reference value predefined for this deformation value.

[0031] It is particularly advantageous if the method assigns at least one load-dependent deformation value to at least three load reference values ​​by assigning at least one deformation value to a range between two consecutive load reference values.

[0032] In this case, it is preferably provided that the evaluation criterion is based on the absolute value of at least one of the load-dependent deformation values ​​relative to a series of at least three load reference values ​​assigned to this deformation value.

[0033] A further advantageous method provides that the evaluation method carries out a comparison of at least one of the load-dependent deformation values ​​with an associated maximum load reference value.

[0034] In this case, it is preferably provided that the evaluation criterion is based on the absolute value of at least one of the load-dependent deformation values ​​relative to a maximum load reference value assigned to the at least one load-dependent deformation value.

[0035] The load of the holding arm can be detected at least in general by means of the analysis criteria, and the transformation of the deformation value and the force F x , F y and F z No subsequent analysis is necessary, namely by detecting that the load-dependent deformation value is assigned to a range between two consecutive load reference values ​​or to an exceeding or approaching of a maximum load reference value.

[0036] A further advantageous method provides that the evaluation method detects at least one load-dependent deformation value in a time-resolved manner.

[0037] It is preferably provided here that in the method the evaluation criterion is based on a time curve of at least one of the deformation values.

[0038] The time curve can be, for example, a brief temporal change in at least one of the deformation values, ie a temporal increase in at least one of the deformation values, in order to detect a brief, in particular sudden, influence on the connecting element.

[0039] Such a brief, sudden influence on the connecting element can occur in particular when the braking action of the trailer vehicle does not take place in the desired manner, for example if the brake system of the trailer vehicle is defective.

[0040] Such a short-term sudden influence lies within a time window of less than 0.5 seconds, for example.

[0041] In this case, it is provided in particular that a gradient characteristic is detected from at least one load-dependent deformation value.

[0042] In such a case, the analysis criterion is based in particular on the edge slope of the slope characteristic, which is compared with a reference value.

[0043] As a result, the behavior of the towed vehicle is problematic at edge inclinations greater than a reference value.

[0044] Another possibility for detecting the time-resolved behavior of the load-dependent deformation values ​​alternatively or additionally provides that the evaluation method determines the time period for the increase of at least one load-dependent deformation value to a maximum value.

[0045] In this case, the analysis criterion is based on whether the duration exceeds a reference time or is less than a reference time, wherein the reference time is preferably less than 0.5 seconds.

[0046] Thus, when the duration is shorter than the reference time, the behavior of the towing vehicle is problematic.

[0047] The aforementioned analysis criterion for the time-resolved detection of at least one of the load-dependent deformation values ​​makes it possible to detect pulse-like influences of the trailer on the retaining arm, in particular on its connecting elements, and thus to detect potentially problematic behaviors of the trailer, such as malfunctioning of the trailer vehicle's inertia brake.

[0048] A further advantageous embodiment of the evaluation method provides that the evaluation method detects the time curve of the oscillation of at least one of the deformation values ​​about a middle value of the oscillating deformation value, in particular the amplitude and / or the period duration.

[0049] An advantageous embodiment of the method according to the invention provides that the evaluation criterion evaluates the amplitude of the oscillation of one of the load-dependent deformation values ​​about a central value and compares this amplitude with a reference value.

[0050] A further solution provides, additionally or alternatively, that the evaluation criterion is based on a comparison of a cycle duration of one of the load-dependent deformation values ​​with a reference cycle duration.

[0051] The analysis of the time curve of the oscillation of at least one of the deformation values ​​makes it possible to determine, in particular by analyzing the magnitude of the amplitude and / or the cycle duration, whether the trailer connected to the connecting element is performing an insignificant movement or an important, therefore dangerous, side-to-side rolling movement for the tractor, for example when the amplitude exceeds a reference value or the cycle duration exceeds a reference cycle duration.

[0052] To improve the functionality of the load analysis stage, it is preferably provided that each of the deformation values ​​taken into account by the load analysis stage is corrected by the no-load correction stage.

[0053] Such a no-load correction stage provides, for example, that the no-load deformation value is determined and subtracted from the determined deformation value under load, so that each deformation value under load is corrected by a fraction of the no-load deformation value.

[0054] The solution according to the invention preferably provides that the no-load correction stage is activated before the holding arm is loaded.

[0055] A further advantageous solution provides that the no-load correction stage is activated after the holding arm has been moved into the working position.

[0056] It is further preferably provided that each of the deformation values ​​applied by the load analysis stage is corrected by a tilt correction stage which, linked to the deformation value of the orientation of the retaining arm when the vehicle is stationary on a horizontal reference surface, corrects the actual orientation of the retaining arm due to the tilt of the vehicle.

[0057] The inclination correction stage preferably provides that the deformation value of the deformation region is changed in such a way that the influence of the changed orientation of the holding arm relative to the orientation of the vehicle at rest on a horizontal reference surface is taken into account in the deformation region.

[0058] For example, provision is made here for the inclination correction stage to operate with a stored inclination correction value.

[0059] The tilt correction value is expediently determined experimentally. The tilt correction value is determined experimentally in particular by detecting it, which takes place at different tilts of the holding arm under load and without load.

[0060] Alternatively or additionally to the aforementioned solution, the task mentioned at the outset is solved according to the invention by a method for detecting forces on a device for connecting a trailer and / or a load-bearing unit which can be assembled at the rear of a motor vehicle body, the device comprising a retaining arm which is fixedly connected to the motor vehicle body at a first end during operation and is constructed at a second end for supporting a connecting element, wherein the retaining arm is provided with a sensor assembly, wherein the retaining arm according to the invention in the method is provided with at least two deformation sensors which react in particular in different ways to three forces acting on the connecting element in spatial directions transverse to each other, and the at least two deformation sensors deliver deformation values ​​from which at least one component force acting on the connecting element is derived.

[0061] The advantage of the solution according to the invention can be seen in that it provides in a simple manner the possibility of determining a reliable value for the acting force.

[0062] It is particularly advantageous if at least one of the values ​​of the force components in a spatial direction is determined.

[0063] It is particularly advantageous if at least the magnitude of the force component in the direction of gravity is determined.

[0064] Furthermore, it is advantageous if at least the magnitude of the force component in the direction of travel of the motor vehicle is determined.

[0065] Furthermore, it is advantageous if at least a magnitude of the force component is determined transversely, in particular perpendicularly, to the vertical longitudinal center plane.

[0066] In order to avoid erroneously deriving deformation values ​​and / or values ​​of component forces acting on the connecting element, it is preferably provided that before deriving the deformation values ​​and / or the component forces, it is detected whether a suitable state for deriving the component forces acting on the connecting element is currently in effect.

[0067] A wide variety of criteria can be applied for this.

[0068] An advantageous solution provides for detecting whether a suitable state for deriving deformation values ​​and / or force components acting on the connecting element is currently in effect by detecting at least one of the following parameters, for example, the voltage supply, in particular the voltage supply of a deformation sensor, the orientation of the vehicle in space and whether the retaining arm is in a working position, the orientation of the vehicle in space referring to an orientation in which the vehicle is essentially stationary in a horizontal plane.

[0069] In order to avoid a falsification of the values ​​of the deformation and / or the force components, at least one of the individual values ​​is advantageously detected in the no-load situation before the individual values ​​are determined.

[0070] It is also advantageous if, after the holding arm has been moved into the operating position, the respective values ​​are detected in the unloaded state, so that it can be avoided that the respective values ​​are determined outside the operating position, which could lead to erroneous results.

[0071] Furthermore, an advantageous solution provides, alternatively or additionally, that the respective value is detected in the no-load state after the connecting element is mounted on the holding arm, also in order to avoid erroneous measurements, if the connecting element is not fixedly connected to the holding arm.

[0072] Furthermore, it is provided that the respective value in the no-load state is stored only if the value does not exceed a predefined value which excludes external forces acting on the connecting element, so that a plausibility check can be performed thereby in order to exclude an erroneous detection of no-load state.

[0073] A further advantageous solution provides that after the detection of an approaching object, in particular after the detection of an approaching trailer or load carrier, the respective value is detected when the vehicle is unladen.

[0074] Finally, it is advantageously provided that after the detection of the individual values ​​in the no-load state, the values ​​in the no-load state are detected again after a predetermined time interval in order to ensure that a value detected once in the no-load state does not remain constant for a long time and thus allow erroneous measurements to occur.

[0075] In order to obtain the most accurate load-dependent value for the force component, it is preferably provided that the corresponding value delivered when no load is applied is subtracted from the value delivered when the force acts on the connecting element in order to obtain at least one of the load-dependent deformation values ​​and / or force component values.

[0076] In order to also avoid an erroneous determination of the forces acting on the connecting element, the forces acting on the connecting element can in particular be determined in such a way that it is ensured as far as possible that the state of the motor vehicle and the state of the device according to the invention allow a most accurate determination of the forces acting on the connecting element.

[0077] Thus, for example, it is provided that when an onboard function of the motor vehicle is being executed, i.e. the motor vehicle is in a state ready for operation but not in a standby state or, for example, a shut-down state, at least one of the deformation values ​​and / or the value of the component force acting on the connecting element is obtained.

[0078] A further advantageous solution provides that at least one of the deformation value and / or the value of the force component acting on the connecting element is obtained when the plug is inserted into the socket associated with the holding arm.

[0079] In this case, the insertion of a plug into a socket assigned to the holding arm is evaluated as a signal that an object is connected to the holding arm, in particular to a connecting element of the holding arm, and thus exerts a force on the holding arm.

[0080] A further expedient solution provides that after the object connected to the connecting element is detected, in particular after the trailer or load carrier connected to the connecting element is detected, at least one of the deformation value and / or the value of the component force acting on the connecting element is determined.

[0081] Such a recognition of an object connected to the connecting element can be performed, for example, by means of a camera system or a sensor arrangement, preferably by means of an ultrasonic sensor arrangement, which is usually also provided for simplifying the reversing of a motor vehicle.

[0082] Another expedient solution provides that at least one of the deformation values ​​and / or the values ​​of the component forces acting on the connecting element is determined when the speed of the motor vehicle is less than five kilometers per hour, in particular when the motor vehicle is stationary, so that the occurrence of dynamic forces can be excluded and it can be ensured that only forces acting statically on the connecting element are detected.

[0083] After at least one of the deformation value and / or the force component value has been determined, this value can be forwarded in a very diverse manner.

[0084] Preferably, provision is made for at least one of the values ​​of the force component acting on the connecting element in the vertical direction to be transmitted.

[0085] Furthermore, it is advantageous if at least one of the values ​​of the force components acting on the connecting element in the direction of travel and in particular parallel to the vertical longitudinal center plane is transmitted.

[0086] Finally, a further expedient solution provides for at least one value of the values ​​of the force components acting transversely to the vertical longitudinal center plane of the holding arm, in particular in an approximately horizontal direction, to be transmitted.

[0087] Furthermore, the transmission of the deformation values ​​and / or the values ​​of the individual force components can take place in a very diverse manner.

[0088] One possibility provides that at least one of the deformation values ​​and / or the values ​​of the individual force components and in particular the measurement accuracy associated with this value is displayed, ie displayed on a presentation unit, for example a display device.

[0089] This makes it easier for the user of the motor vehicle to quickly recognize the quality of the determination of the deformation value and / or the value of the individual force components and to draw conclusions therefrom that are necessary for the movement of the motor vehicle.

[0090] In order to be able to quickly assess the deformation values ​​and / or the values ​​of the force components, one solution in particular provides for at least one of the values ​​of the individual force components to be qualitatively represented in order to be able to quickly draw conclusions about the forces acting on the device according to the invention without a detailed examination.

[0091] A further advantageous solution provides that the magnitude of the force component acting on the connecting element in the vertical direction is indicated in relation to the support load predefined for the respective motor vehicle.

[0092] Furthermore, an advantageous solution provides that the magnitude of the force component acting in the direction of travel is indicated in relation to the maximum tensile force in order to also simplify the influence of the forces acting on the vehicle for the motor vehicle user.

[0093] A further advantageous solution provides that at least one of the values ​​of the component forces acting on the connecting element is transmitted to an electronic stability system of the motor vehicle, so that influencing forces of the towing vehicle or load carrier can be easily taken into account when electronically stabilizing the vehicle.

[0094] Furthermore, an advantageous solution provides that the magnitude of the force component acting on the connecting element is transmitted to a chassis control system of the motor vehicle.

[0095] With regard to the explanation so far of the individual embodiment variants of the method according to the invention, no further explanation has been given of how the magnitude of the force component acting on the connecting element is related to the magnitude of the deformation.

[0096] An advantageous solution therefore provides that the magnitude of the force component acting on the connecting element and the magnitude of the deformation are correlated with one another by means of a conversion factor.

[0097] Such a correlation is a simple mathematical solution that takes into account different relationships.

[0098] In particular, it is provided that the deformation values ​​delivered by the deformation sensor and the values ​​of the force components in three spatial directions transverse to one another are correlated with one another by means of the transformation coefficients of the transformation matrix.

[0099] No further explanation has been given so far regarding the determination of the conversion coefficients of the conversion matrix.

[0100] An advantageous solution therefore provides for the transformation coefficients of the transformation matrix to be determined within the framework of a calibration process.

[0101] For example, such a calibration process provides that a deformation value delivered by the deformation sensor is detected when a defined force component acts on the connecting element, wherein different force components acting on the connecting element are applied successively during the calibration process in order to generate different deformation values.

[0102] In particular, it is provided that during the calibration process the connecting element is influenced by a defined force component in one of three spatial directions transverse to one another and that a deformation value delivered by the deformation sensor is detected.

[0103] The calibration can be carried out particularly advantageously if, during the calibration process, each force component acting in one of the three spatial directions has the same magnitude, wherein the individual force components act in particular successively on the connecting element in order to obtain individual deformation values ​​for each of the force components.

[0104] A particularly simple mathematical model provides that the conversion factor is determined under the assumption that a linear relationship exists between the magnitudes of the force components in the three spatial directions transverse to one another and the deformation magnitudes delivered by the deformation sensor.

[0105] Alternatively or additionally to this, it is also conceivable to determine the conversion factor using other methods, for example by means of the method of least squares.

[0106] A particularly simple approach provides that three spatial directions transverse to one another are perpendicular to one another.

[0107] An improved method for determining the numerical value of a component force provides that, starting from a connecting element as a midpoint in space, the space is divided into eight octants around the connecting element, the octants being defined by three spatial directions transverse to one another, and the connecting element is influenced by the component forces in each octant to obtain a set of conversion coefficients in each octant, and furthermore, deformation values ​​are detected and, for the component forces in each octant, conversion coefficients based on the octants are obtained.

[0108] However, in order to be able to use conversion coefficients based on octants, it is preferably provided that a conversion matrix in the conversion matrix is ​​applied to obtain the value of the component force acting on the connecting element, and then a check is made to which octant of the octants the component force is assigned, and then the value of the component force is again obtained with the aid of the conversion matrix assigned to the octant, wherein the conversion matrix can be one of a non-octant-based conversion matrix or an octant-based conversion matrix.

[0109] According to the invention, the task of a device of the type described at the outset is also solved, optionally or supplementarily to the aforementioned solution, in that the forces applied to the connecting element during operation and transmitted by the retaining arm to the motor vehicle body are detected by an evaluation and analysis unit having a sensor assembly, wherein the sensor assembly has at least three deformation sensors, and the at least three deformation sensors of the sensor assembly are in particular arranged on the same side of a neutral fiber of the retaining arm, the neutral fiber not being deformed in length when the retaining arm is bent and deformed.

[0110] The solution according to the invention has the advantage that deformations of the holding arm can be detected in a simple manner by means of the sensor arrangement.

[0111] Furthermore, the object mentioned in the introduction is achieved by means of devices according to claims 40 to 79 .

[0112] According to the invention, the task of a device of the type described at the outset is also solved, optionally or supplementarily to the aforementioned solution, in that the forces applied to the connecting element during operation and transmitted by the retaining arm to the motor vehicle body are detected by an evaluation and analysis unit having a sensor assembly, wherein the sensor assembly has at least two deformation sensors, and the at least two deformation sensors of the sensor assembly are in particular arranged on the same side of a neutral fiber of the retaining arm, the neutral fiber not being deformed in length when the retaining arm is bent and deformed.

[0113] The solution according to the invention has the advantage that deformations of the holding arm can be detected in a simple manner by means of the sensor arrangement.

[0114] It is particularly advantageous here if all sensors of the sensor arrangement are arranged on the same side of a neutral fiber of the holding arm which does not deform during bending deformation of the holding arm.

[0115] Furthermore, according to the invention, in a device of the type described at the outset, the task mentioned at the outset is achieved in that a force detection module is provided on one side of the retaining arm, which comprises a sensor assembly which detects the forces applied to the connecting element during operation and the forces transmitted by the retaining arm to the motor vehicle body.

[0116] Such a force detection module provides an advantageous and simple solution for detecting the forces acting on the holding arm.

[0117] In particular, it is provided here that the sensor arrangement of the force detection module has at least three, in particular four, deformation sensors.

[0118] No further explanation has been given so far here regarding the arrangement of the motor vehicle module.

[0119] Therefore, an advantageous solution provides that the force detection module is not arranged on the side of the holding arm facing the roadway in the operating state, which means that the force detection module is only arranged on the surface of the holding arm not facing the roadway, because this prevents the holding arm from contacting objects on the roadway and damaging the force detection module, or prevents the holding arm from contacting objects arranged on the surface soil and damaging the force detection module.

[0120] It is particularly advantageous here if the force detection module is arranged in the operating state on the side of the holding arm facing away from the roadway.

[0121] Such an arrangement of the force detection module has the advantage that it shows the side of the force detection module that is least damaged.

[0122] In order to be able to advantageously arrange a deformation sensor on the one hand and to be able to advantageously transmit the deformation of the holding arm to the deformation sensor on the other hand, another solution to the task mentioned in the introduction preferably provides that the forces applied to the connecting element during operation and transmitted by the holding arm to the motor vehicle body are detected by an evaluation unit having a sensor assembly, wherein the sensor assembly has at least two deformation sensors and the sensor assembly is arranged on at least one deformation transmission element connected to the holding arm.

[0123] In this case, the deformation can be provided at different deformation transmission elements.

[0124] In another solution to the task mentioned at the outset, it is particularly advantageous if the forces applied to the connecting element during operation and transmitted by the retaining arm to the motor vehicle body are detected by an evaluation unit having a sensor assembly, wherein the sensor assembly has at least two deformation sensors and all deformation sensors of the sensor assembly are arranged on a common deformation transmission element.

[0125] If each of the at least two deformation sensors detects a deformation of the holding arm of different magnitude when one and the same force acts on the connecting element, then the force acting on the holding arm can be detected particularly advantageously, since differently oriented forces that can act on the connecting element can thereby be separated in a simple manner.

[0126] With regard to the connection of the deformation transmission element to the holding arm, it is preferably provided that the deformation transmission element is motion-free and thereby rigidly connected to the holding arm in at least two fastening regions, and that at least one of the deformation sensors is arranged between the fastening regions of the deformation element.

[0127] It is further advantageous if the deformation transmission element is connected to the holding arm by means of at least three fastening regions and if at least one of the deformation sensors is arranged between two of the fastening regions.

[0128] No further information has been given so far with regard to the connection of the fastening region of the deformation transmission element to the holding arm.

[0129] In principle, it is conceivable for the fastening region to be directly connected to the holding arm, for example by welding.

[0130] However, a particularly advantageous solution provides that the deformation transmission element is connected to the holding arm in the fastening region by means of an engagement element.

[0131] Such a connection to the holding arm by means of the engagement element can be realized particularly advantageously if the engagement element is rigidly connected to the holding arm on the one hand and to the fastening region of the deformation transmission element on the other hand.

[0132] A particularly advantageous solution provides that the engagement element is formed on the holding arm, in particular formed integrally.

[0133] When such a connection of the holding arm to the deformation transmission element is arranged, it is preferably provided that the engagement elements transmit deformations of the holding arm in deformation regions of the holding arm, respectively located between the engagement elements, to the fastening region of the deformation transmission element.

[0134] It is particularly advantageous if a deformation region of the holding arm is respectively present between two engagement elements.

[0135] A particularly advantageous solution provides that the holding arm has at least two deformation regions, the deformation of which is transmitted via engagement elements arranged on both sides to fastening regions of the deformation transmission element, between which there is a deformed region of the deformation transmission element.

[0136] With regard to the arrangement of the two deformation regions in the holding arm, it is particularly advantageous if at least two deformation regions are arranged one behind the other in the direction of extension of the holding arm.

[0137] Furthermore, for the detection of deformations in the deformed regions it is advantageous if at least one deformation sensor is arranged in one of the deformed regions of the deformation transmission element.

[0138] In this case, in particular at least one deformation sensor is arranged in each deformable region of the deformation transmission element.

[0139] Furthermore, it is expediently provided that each deformable region is connected to a non-deformable region of the deformation transmission element and that the fastening regions are respectively located in a non-deformable region, so that the fastening regions are surrounded by the respective non-deformable regions.

[0140] In this case, a non-deformable region means in particular that it has a significantly higher rigidity than a deformable region, which means that the rigidity of this region is at least twice, in a better case at least five times, higher than that of the deformable region.

[0141] The advantage of this solution is that the largest possible part of the deformation transmitted from the deformation area of ​​the holding arm to the deformation transmission element is not distributed over the entire deformation transmission element, but is essentially effective in the deformed area, in which, in particular, the deformation sensor is provided, so that the largest possible deformation is thus generated in this deformed area and the smallest possible deformation or no deformation is achieved in the less deformable area of ​​the deformation transmission element.

[0142] It is particularly advantageous if the deformable regions are arranged in each case between two less deformable regions.

[0143] Furthermore, for the purpose of ideally transferring as much as possible of the deformation transmitted to the deformation transmission element to the deformed region, it is advantageous if the less deformable region and the deformed region are arranged successively in the deformation direction, which means that the less deformable region and the deformed region are arranged successively in the direction in which substantial deformation is transmitted to the deformation transmission element.

[0144] Furthermore, it is advantageous if the deformed region is designed as a deformation concentration region.

[0145] The deformation concentration region means in particular that a major part of the deformation transmitted to the deformation transmission element or a major part of the deformation influencing the deformation transmission element, ie more than 50%, more preferably more than 70%, is formed in the deformation concentration region.

[0146] Such a configuration of the deformed region has the advantage that the deformation energy is essentially concentrated in this region and thus the greatest possible deformation can be detected by the deformation sensors.

[0147] No further information has been given so far regarding the material of the deformation transmission element.

[0148] It is thus preferably provided that, outside the region where deformation occurs, the material of the deformation transfer element is constructed as a material that is not easily deformed or a material that is not actively deformed, which means, for example, that outside the region where deformation occurs, only less than 30%, better still less than 20%, preferably less than 10% of the deformation that is transmitted to the deformation transfer element or influences the deformation of the deformation transfer element occurs.

[0149] On the other hand, it is preferably provided that in the deformed region the material of the deformation transmission element is prone to deformation or is suitable for deformation by suitable shaping, for example by a cross-sectional constriction.

[0150] In order to be able to compensate for deformations of the deformation transmission element that are not caused by deformations of the holding arm, it is preferably provided that the deformation transmission element has, in addition to the deformed regions, non-deformed regions, on which at least one reference deformation sensor is arranged.

[0151] In the deformation-free area, due to its design and arrangement, basically no deformation occurs which is transmitted to the deformation transmission element or which influences the deformation transmission element, which means in particular that less than 20%, better less than 10%, preferably less than 5% of the deformation occurs which is transmitted to the deformation transmission element or which influences the deformation transmission element.

[0152] With the aid of such a reference deformation sensor in a deformation-free area, conditional material deformations in the deformation transfer element caused by other influences are detected by the reference deformation sensor, and since the material deformations are also detected by the deformation sensor, the material deformations can subsequently be corrected therefor, which are caused, for example, by thermal influences and which serve as a condition for the deformation transmitted to the deformation transfer element or influence the deformation of the deformation transfer element.

[0153] It is therefore preferably provided that the respective non-deformed region consists of the same material as the deformed region.

[0154] Furthermore, it is preferably provided that the respective non-deformable region is connected on one side to a less deformable region of the deformation transmission element.

[0155] A particularly advantageous geometrical configuration provides that the non-deformed region of the deformation transmission element is designed in the shape of a tongue.

[0156] Furthermore, it is preferably provided that the non-deformed region of the deformation transmission element is produced from the same material as the deformed region, in particular has the same material thickness.

[0157] In order to optimally correlate the effects detected by the reference deformation sensor with the effects detected by the deformation sensor, it is preferably provided that the reference deformation sensor is thermally connected to the deformation transmission element.

[0158] In particular, it is thereby possible to thermally connect the reference deformation sensor to the deformation sensor by means of the deformation transmission element.

[0159] In particular, when each deformation sensor is equipped with a reference deformation sensor, an optimal thermal connection is achieved if a thermal connection is established between each deformation sensor and the reference deformation sensor assigned to the deformation sensor, and between each deformed region equipped with the deformation sensor and a non-deformed region assigned to the deformed region, and the non-deformed region carries the assigned reference deformation sensor.

[0160] It is generally advantageous if the non-deformed region carrying the respective reference deformation sensor has the same thermal properties as the deformed region carrying the respective deformation sensor.

[0161] In order to achieve as large a deformation as possible in the region of the reference deformation sensor as in the region of the deformation sensor, it is expediently provided that the non-deformed regions carrying the reference deformation sensor have a similar, preferably identical, geometry as the deformed regions carrying the deformation sensor.

[0162] In this case, it is also particularly advantageous if the non-deformed region of the deformation transmission element is produced from the same material as the deformed region of the deformation transmission element.

[0163] In order to monitor the functional capability of the reference deformation sensor, it is preferably provided that at least one temperature sensor for functional monitoring is associated with the reference deformation sensor.

[0164] Preferably, a temperature sensor is assigned to each reference deformation sensor for function monitoring.

[0165] No further information has been given so far with regard to the design of the deformation transmission element.

[0166] An advantageous solution therefore provides that the deformation transmission element is designed similarly to a plate and that each deformed region carrying a deformation sensor is designed by a cross-sectional constriction of the deformation transmission element.

[0167] In particular, it is provided here that the cross-sectional constriction of the deformation transmission element is formed by a constriction of the surface area of ​​the deformation transmission element.

[0168] The deformation sensors and the reference deformation sensors can be sensors designed in a very diverse manner which are able to detect extension processes and / or compression processes in the deformed region.

[0169] One possibility provides that the deformation sensor and the reference deformation sensor are designed as strain sensors, in particular as strain gauges.

[0170] Another possibility provides that the deformation sensor and the reference deformation sensor are designed as magnetostrictive sensors or as optical sensors which can detect extensions and compressions.

[0171] For optimal compensation of the strain sensors, it is particularly advantageous if a reference strain sensor assigned to a strain sensor is identical to the assigned strain sensor.

[0172] According to the invention, the object mentioned at the outset is also achieved in particular in that the retaining arm has a first deformation region and a second deformation region between the first end and the second end, and when there is a force acting parallel to the direction of travel and in the longitudinal center plane of the retaining arm, the deformation regions each undergo a deformation that is different from the deformation that occurs when there is a force acting transversely to the direction of travel and in the longitudinal center plane.

[0173] The advantage of the solution according to the invention can be seen from this, that when there is a force acting in the longitudinal middle plane of the retaining arm parallel to the direction of travel and a force acting in the longitudinal middle plane transversely to the direction of travel, especially perpendicularly to the direction of travel, in particular when these two forces are of comparable magnitude, the first deformation region and the second deformation region behave differently, which means that they deform with different intensities, whereby it is possible to distinguish between the force acting in the longitudinal middle plane of the retaining arm parallel to the direction of travel and the force acting in the longitudinal middle plane of the retaining arm transversely to the direction of travel when evaluating the signal of the deformation sensor through the different deformations of the first deformation region and the second deformation region.

[0174] What is even more beneficial is that when there is a force acting transversely to the longitudinal middle plane, in particular perpendicular to the longitudinal middle plane, and in particular the magnitude of this force is the same as the magnitude of the force acting in the longitudinal middle plane, parallel to or transverse to the direction of travel, the first deformation zone and the second deformation zone also behave differently, which indicates that the intensity of their deformation is different.

[0175] The different behavior of the first and second deformation regions can be achieved by different configurations of the first and second deformation regions in the holding arm, in particular by different cross sections and / or different extensions and / or different lengths.

[0176] In this case, it is provided in particular that the first deformation region and the second deformation region are arranged one behind the other in the direction of extension of the holding arm.

[0177] In the explanation so far of the solution according to the invention, no further explanation has been given with regard to the processing of the deformation sensor signal and the reference deformation sensor signal.

[0178] An advantageous solution therefore provides that each deformation sensor is connected to an associated reference deformation sensor in a Wheatstone bridge.

[0179] This makes it possible in a simple manner to compensate for conditioned effects, in particular thermal effects, without deformation of the deformation region of the holding arm by direct use of the deformation sensor signal and the reference deformation sensor signal.

[0180] Furthermore, an advantageous solution provides that the evaluation unit has a processor which converts a value corresponding to the deformation in the deformed region into a corresponding value for a force acting on the connecting element in three mutually transverse, in particular mutually perpendicular, spatial directions using conversion values ​​which are obtained by calibration and stored in a memory.

[0181] The forces acting on the connecting element in three spatial directions transverse to one another, in particular perpendicular to one another, can therefore be derived from the values ​​corresponding to the deformation.

[0182] It is particularly advantageous here that two forces parallel to the longitudinal middle plane of the holding arm, in particular two forces in the longitudinal middle plane of the holding arm, are transverse to each other, in particular perpendicular to each other, and a third force is transverse to the longitudinal middle plane of the holding arm, in particular perpendicular to the longitudinal middle plane of the holding arm.

[0183] If converted values ​​for the force combinations acting on the connecting element in different octants are stored in a memory, the conversion of values ​​corresponding to the deformation can be improved, since the different converted values ​​allow an optimal adaptation to the actual situation.

[0184] According to the solution according to the invention, the evaluation unit is designed in particular in such a way that the value of the deformation sensor and, in particular, also the value of the reference deformation sensor is detected in order to ascertain the deformation.

[0185] In order to be able to perform a functional test of the reference deformation sensor, it is provided that the evaluation unit includes the value of at least one temperature sensor for testing the functional test of the reference deformation sensor.

[0186] Preferably, the evaluation unit detects the value of a temperature sensor respectively assigned to the reference deformation sensor in order to carry out a functional test of the reference deformation sensor.

[0187] In this case, the at least one temperature sensor or the plurality of temperature sensors can be arranged either on a printed circuit board carrying the evaluation unit or on the deformation transmission element.

[0188] In the above-mentioned embodiments, no further indication has been given as to how the retaining arm and the connecting element can be connected.

[0189] An advantageous solution provides that the holding arm carries the connecting element at its second end.

[0190] In this case, it is particularly advantageous if the holding arm and the connecting element form connected parts, so that it is not possible to separate the holding arm and the connecting element.

[0191] In such a case, it is provided in particular that the holding arm is designed as a ball neck and carries a connecting element at the second end, which connecting element comprises a connecting ball.

[0192] A further advantageous solution provides that the holding arm comprises a receiving body which is designed to detachably receive the connecting element.

[0193] For example, the connecting element is part of the carrying system and serves to connect the carrying system to the holding arm.

[0194] For example, the connecting element is designed as a connecting element for a carrying system for goods, in particular for luggage or bicycles.

[0195] In this case, the receiving body is designed in particular such that it has an insertion receptacle which is accessible through the insertion opening.

[0196] Preferably, provision is made for the aforementioned receiving body of the holding arm that the connecting element comprises the supporting arm.

[0197] In this case, the support arm is expediently provided with an insertion section which can be inserted and fixed in the insertion receptacle.

[0198] The carrying arm is, for example, part of a carrying system.

[0199] In another embodiment, it is optionally provided that the support arm carries the connecting ball.

[0200] In another embodiment, the support arm is provided with other connecting means, for example with a connecting opening.

[0201] For precise fixing of the support arm, it is expedient if the insertion section is received in the insertion receptacle in a form-fitting manner transversely to the insertion direction and is fixed in the functional state in the insertion direction by a form-fitting body.

[0202] The above description of the solution according to the invention therefore includes in particular the different combinations of features defined by the following consecutively numbered embodiments:

[0203] 1. A method for operating a device for connecting a trailer and / or a load-bearing unit (360) which can be assembled at the rear of a motor vehicle body, the device comprising a holding arm (30) which is fixedly connected to the motor vehicle body (12) at a first end (32) during operation and carries a connecting element (40) for the trailer (350) and / or the load-bearing unit (360) at a second end, wherein a force applied to the connecting element (40) during operation and transmitted by the holding arm (30) to the motor vehicle body (12) is detected by an evaluation unit (230) with the aid of deformation sensors (172, 174, 176, 178), wherein the holding arm (30) has at least two deformation sensors. Region (82, 84), when force acts on the holding arm (30), the deformation performance of the deformation region is detected by at least one deformation sensor (172, 174, 176, 178), and the deformation sensor is rigidly connected to the corresponding deformation region (82, 84) of the holding arm (30), so as to detect the deformation performance of the deformation region, wherein the evaluation and analysis unit (230) has a load analysis stage (233), which starts from the deformation values ​​(D152, D154, D156, D2158) of the at least two deformation regions (82, 84) obtained from the deformation sensors (172, 174, 176, 178), and uses an analysis method to obtain at least one load type of the holding arm (30).

[0204] 2. The method according to embodiment 1, wherein the load analysis stage (233) uses the deformation values ​​(D152, D154, D156, D158) without converting them to the vertical direction (F z ) and / or forces in the longitudinal direction of the vehicle (24) and / or forces transverse to the longitudinal midplane of the vehicle (F y )’s force.

[0205] 3. The method according to any one of the preceding embodiments, wherein at least one analytical method is a numerical comparison method.

[0206] 4. A method according to any one of the preceding embodiments, wherein the numerical comparison method compares the deformation numerical values ​​(D) with each other, and / or compares the deformation numerical values ​​with reference numerical values ​​(RB0, S, RAWB, RFWB, B1...B6, RFS, ZR, RAS, RPS).

[0207] 5. A method according to implementation scheme 4, wherein the reference value is a preset, especially saved reference value (RB0, S, RAWB, RFWB, B1...B6, RFS, ZR, RAS, RPS).

[0208] 6. A method according to implementation scheme 4 or 5, wherein the reference values ​​(RB0, S, RAWB, RFWB, B1...B6, RFS, ZR, RAS, RPS) are obtained by experiments.

[0209] 7. A method according to embodiment 6, wherein the reference value is obtained by load testing a representative retaining arm (30).

[0210] 8. The method according to any of the preceding embodiments, wherein at least one analysis method evaluates the absolute value of the load-dependent deformation value (D).

[0211] 9. A method according to embodiment 8, wherein the analysis criterion is based on a comparison of the absolute value of the load-dependent deformation value (D) with a threshold value (S) serving as a reference value.

[0212] 10. A method according to embodiments 8 or 9, wherein at least one analysis criterion is based on a comparison of each of the absolute values ​​of the load-dependent deformation values ​​(D) with a stored reference value range (RB0).

[0213] 11. A method according to any of the preceding embodiments, wherein at least one analysis method compares at least one deformation value (D) of a deformation region (82) with at least one deformation value (D) of at least one other deformation region (84).

[0214] 12. A method according to any of the preceding embodiments, wherein the analysis method is based on a comparison of the behavior of deformation values ​​(D152, D154) of deformation areas that are highly sensitive to the support load relative to deformation areas that are less sensitive to the support load.

[0215] 13. A method according to embodiments 11 or 12, wherein the analytical method results in the difference between two deformation values ​​(D).

[0216] 14. A method according to embodiment 13, wherein the analysis method obtains the ratio of the difference between the two deformation values ​​(D) relative to the maximum value of the two deformation values ​​(D).

[0217] 15. A method according to any one of embodiments 11 to 14, wherein the analysis criterion is based on a comparison of the performance of at least one deformation value (D152, D154) of a deformation region (82) that is highly sensitive to support loads relative to at least one deformation value (D154, D156) of a deformation region (84) that is less sensitive to support loads.

[0218] 16. A method according to embodiment 15, wherein the analysis criterion is based on the ratio of the difference between the deformation values ​​(D) and the maximum value of two deformation values ​​(D) compared to a stored reference value range (RAWB, RFWB).

[0219] 17. A method according to any one of the preceding embodiments, wherein the size of the deformation value (D152, D154, D156, D158) determined by the load is obtained when there is at least one deformation area (82, 84) by comparing the deformation value (D152, D154, D156, D158) determined by the load with at least one load reference value (B1...B6) preset for the deformation value.

[0220] 18. A method according to embodiment 17, wherein the analysis method assigns at least one load-dependent deformation value (D152, D154, D156, D158) to a plurality of preset load reference values ​​(B1...B6) by assigning the at least one load-dependent deformation value (D152, D154, D156, D158) to a range (BS1, BS2, BS3, BS4, BS5) between two consecutive load reference values ​​(B1...B6).

[0221] 19. A method according to embodiments 17 or 18, wherein the analysis criterion is based on the assignment of at least one of the deformation values ​​to a series containing at least three load reference values ​​(B1 to B6) prepared for the deformation value.

[0222] 20. A method according to any of the preceding embodiments, wherein the analysis method implements a comparison of at least one of the deformation values ​​(D152, D154, D156, D158) with an assigned maximum load reference value (B6).

[0223] 21. A method according to embodiment 20, wherein the analysis criterion is based on the assignment of at least one of the load-dependent deformation values ​​(D152, D154, D156, D158) relative to a maximum load reference value (B6) assigned to the deformation value.

[0224] 22. A method according to any of the preceding embodiments, wherein the analysis method detects at least one of the load-dependent deformation values ​​(D152, D154, D156, D158) in a time-resolved manner.

[0225] 23. A method according to embodiment 22, wherein the analysis criterion is based on a short-term temporal change of at least one of the deformation values ​​(D152, D154, D156, D158).

[0226] 24. A method according to embodiment 23, wherein the analysis method detects the slope characteristic from at least one of the load-dependent deformation values ​​(D152, D154, D156, D158).

[0227] 25. A method according to embodiment 24, wherein the analysis criterion compares the edge slope (FS) of the slope characteristic with a stored reference value (RFS).

[0228] 26. A method according to any one of embodiments 22 to 25, wherein the analysis method determines the duration (Z) for at least one of the load-dependent deformation values ​​(D) to grow to a maximum value.

[0229] 27. A method according to any one of embodiments 22 to 26, wherein the analysis criterion is based on comparing the duration (Z) with a reference time (RZ).

[0230] 28. A method according to any one of embodiments 22 to 27, wherein the analysis criterion is based on the time curve of at least one of the deformation values.

[0231] 29. A method according to any one of embodiments 22 to 28, wherein the analysis method detects the time curve of the oscillation of at least one of the deformation values ​​(D152, D154, D156, D158) around the middle value of the oscillating deformation value (D152, D154, D156, D158).

[0232] 30. A method according to embodiment 29, wherein the analysis criterion is based on a comparison of the amplitude (AS) of the oscillation of one of the load-dependent deformation values ​​(D152, D154, D156, D158) around a middle value with a reference value (RAS).

[0233] 31. A method according to embodiments 28 to 30, wherein the analysis criterion is based on a comparison of a period duration (PS) of one of the load-dependent deformation values ​​with a reference period duration (RPS).

[0234] 32. A method according to the preamble of embodiment 1 or according to any of the preceding embodiments, wherein each deformation value (D) applied by the load analysis stage (233) is corrected by a no-load correction stage (285).

[0235] 33. A method according to embodiment 32, wherein the deformation value (Dl) when no-load is obtained by the no-load correction stage (285) and is subtracted from the deformation value (D) obtained when loaded.

[0236] 34. A method according to embodiment 32 or 33, wherein the no-load correction stage (285) is activated before the retaining arm (30) is loaded.

[0237] 35. A method according to any one of embodiments 32 to 34, wherein the no-load correction stage (285) is activated after the retaining arm (30) moves into the working position.

[0238] 36. A method according to any of the preceding embodiments, wherein each deformation value (D) applied by the load analysis stage (233) is corrected by a tilt correction stage (283), which is associated with the deformation value (D) of the orientation of the retaining arm (30) when the vehicle is stationary on a horizontal reference surface, correcting the actual orientation of the retaining arm (30) due to the tilt of the vehicle.

[0239] 37. A method according to embodiment 36, wherein the tilt correction stage (283) changes the deformation value (D) of the deformation zone (152, 154, 156, 158) in such a way that, in the deformation zone, the influence of the changed orientation of the retaining arm (30) relative to the orientation of the vehicle at rest on a horizontal reference surface is taken into account.

[0240] 38. A method according to embodiment 36 or 37, wherein the tilt correction stage (283) operates with a stored tilt correction value.

[0241] 39. A method according to embodiment 38, wherein the tilt correction stage (283) operates with an experimentally determined tilt correction value.

[0242] 40. A device for connecting a trailer and / or a load-bearing unit (360) that can be assembled at the rear of a motor vehicle body, the device comprising a retaining arm (30), which is fixedly connected to the motor vehicle body (12) at a first end (32) during operation and carries a connecting element (40) for the trailer (350) and / or the load-bearing unit (360) at a second end, wherein the force applied to the connecting element (40) during operation and transmitted by the retaining arm (30) to the motor vehicle body (12) is detected by an evaluation unit (230) with the aid of deformation sensors (172, 174, 176, 178), wherein the retaining arm (30) has at least two deformation regions. (82, 84), when a force acts on the retaining arm (30), the deformation performance of the deformation area is detected by at least one deformation sensor (172, 174, 176, 178), and the deformation sensor and the corresponding deformation area (82, 84) of the retaining arm (30) are rigidly connected, so as to detect the deformation performance of the deformation area, wherein the evaluation and analysis unit (230) has a load analysis stage (233), which starts from the deformation values ​​(D152, D154, D156, D2158) of the at least two deformation areas (82, 84) obtained from the deformation sensors (172, 174, 176, 178), and uses an analysis method to obtain at least one load type of the retaining arm (30).

[0243] 41. The apparatus according to embodiment 40, wherein the load analysis stage (233) uses the deformation values ​​(D152, D154, D156, D158) without converting them into vertical directions (F z ) and / or forces in the longitudinal direction of the vehicle (24) and / or forces transverse to the longitudinal midplane of the vehicle (F y )’s force.

[0244] 42. An apparatus according to any one of embodiments 40 to 41, wherein at least one analysis method is a numerical comparison method.

[0245] 43. An apparatus according to any one of embodiments 40 to 42, wherein the numerical comparison method compares the deformation numerical values ​​(D) with each other, and / or compares the deformation numerical values ​​with reference numerical values ​​(RB0, S, RAWB, RFWB, B1...B6, RFS, ZR, RAS, RPS).

[0246] 44. An apparatus according to embodiment 43, wherein the reference values ​​are preset, in particular saved reference values ​​(RB0, S, RAWB, RFWB, B1...B6, RFS, ZR, RAS, RPS).

[0247] 45. An apparatus according to embodiment 43 or 44, wherein the reference values ​​(RB0, S, RAWB, RFWB, B1 ... B6, RFS, ZR, RAS, RPS) are obtained by experiments.

[0248] 46. ​​An apparatus according to embodiment 45, wherein the reference value is obtained by load testing a representative retaining arm (30).

[0249] 47. An apparatus according to any one of embodiments 40 to 46, wherein at least one analysis method evaluates the absolute value of the deformation value (D) determined by the load.

[0250] 48. An apparatus according to embodiment 47, wherein the analysis criterion is based on a comparison of the absolute value of the load-dependent deformation value (D) with a threshold value (S) serving as a reference value.

[0251] 49. An apparatus according to embodiments 47 or 48, wherein at least one analysis criterion is based on a comparison of each absolute value of the load-dependent deformation value (D) with a stored reference value range (RB0).

[0252] 50. An apparatus according to any one of embodiments 40 to 49, wherein at least one analytical method compares at least one deformation value (D) of a deformation region (82) with at least one deformation value (D) of at least one other deformation region (84).

[0253] 51. An apparatus according to any one of embodiments 40 to 50, wherein the analysis method is based on a comparison of the deformation values ​​(D152, D154) of deformation areas that are highly sensitive to support loads relative to deformation areas that are less sensitive to support loads.

[0254] 52. An apparatus according to embodiments 50 or 51, wherein the analysis method results in a difference between two deformation values ​​(D).

[0255] 53. An apparatus according to embodiment 52, wherein the analysis method obtains the ratio of the difference between the two deformation values ​​(D) relative to the maximum value of the two deformation values ​​(D).

[0256] 54. An apparatus according to any one of embodiments 50 to 53, wherein the analysis criterion is based on a comparison of the performance of at least one deformation value (D152, D154) of a deformation region (82) that is highly sensitive to support loads relative to at least one deformation value (D154, D156) of a deformation region (84) that is less sensitive to support loads.

[0257] 55. An apparatus according to embodiment 54, wherein the analysis criterion is based on the ratio of the difference between the deformation values ​​(D) and the maximum value of two deformation values ​​(D) compared to a stored reference value range (RAWB, RFWB).

[0258] 56. An apparatus according to any one of embodiments 40 to 55, wherein the size of the load-determined deformation value (D152, D154, D156, D158) obtained when there is at least one deformation area (82, 84) is determined by an analytical method by comparing the load-determined deformation value (D152, D154, D156, D158) with at least one load reference value (B1...B6) preset for the deformation value.

[0259] 57. An apparatus according to embodiment 56, wherein the analysis method assigns at least one load-dependent deformation value (D152, D154, D156, D158) to a plurality of preset load reference values ​​(B1...B6) by assigning the at least one load-dependent deformation value (D152, D154, D156, D158) to a range (BS1, BS2, BS3, BS4, BS5) between each two consecutive load reference values ​​(B1...B6).

[0260] 58. An apparatus according to embodiments 56 or 57, wherein the analysis criterion is based on the assignment of at least one of the deformation values ​​to a series containing at least three load reference values ​​(B1 to B6) prepared for the deformation value.

[0261] 59. An apparatus according to any one of embodiments 40 to 58, wherein the analysis method implements a comparison of at least one of the deformation values ​​(D152, D154, D156, D158) with an assigned maximum load reference value (B6).

[0262] 60. An apparatus according to embodiment 59, wherein the analysis criterion is based on the assignment of at least one of the load-dependent deformation values ​​(D152, D154, D156, D158) relative to a maximum load reference value (B6) assigned to the deformation value.

[0263] 61. An apparatus according to any one of embodiments 40 to 60, wherein the analysis method detects at least one of the load-dependent deformation values ​​(D152, D154, D156, D158) in a time-resolved manner.

[0264] 62. An apparatus according to embodiment 61, wherein the analysis criterion is based on a short-term temporal change of at least one of the deformation values ​​(D152, D154, D156, D158).

[0265] 63. An apparatus according to embodiment 62, wherein the analysis method detects a slope characteristic from at least one of the load-dependent deformation values ​​(D152, D154, D156, D158).

[0266] 64. An apparatus according to embodiment 63, wherein the analysis criterion compares the edge slope (FS) of the slope characteristic with a stored reference value (RFS).

[0267] 65. An apparatus according to any one of embodiments 61 to 64, wherein the analysis method determines the duration (Z) for at least one of the load-dependent deformation values ​​(D) to grow to a maximum value.

[0268] 66. An apparatus according to any one of embodiments 61 to 65, wherein the analysis criterion is based on comparing the duration (Z) with a reference time (RZ).

[0269] 67. An apparatus according to any one of embodiments 61 to 66, wherein the analysis criterion is based on a time curve of at least one of the deformation values.

[0270] 68. An apparatus according to any one of embodiments 61 to 67, wherein the analysis method detects the time curve of the oscillation of at least one of the deformation values ​​(D152, D154, D156, D158) around the middle value of the oscillating deformation value (D152, D154, D156, D158).

[0271] 69. An apparatus according to embodiment 68, wherein the analysis criterion is based on a comparison of the amplitude (AS) of the oscillation of one of the load-dependent deformation values ​​(D152, D154, D156, D158) around a middle value with a reference value (RAS).

[0272] 70. An apparatus according to embodiments 67 to 69, wherein the analysis criterion is based on a comparison of a period duration (PS) of one of the load-dependent deformation values ​​with a reference period duration (RPS).

[0273] 71. An apparatus according to the preamble of embodiment 40 or according to any one of embodiments 40 to 68, wherein each deformation value (D) applied by the load analysis stage (233) is corrected by a no-load correction stage (285).

[0274] 72. An apparatus according to embodiment 71, wherein the deformation value (Dl) when no-load is obtained by the no-load correction stage (285) and is subtracted from the deformation value (D) obtained when loaded.

[0275] 73. An apparatus according to embodiment 71 or 72, wherein the no-load correction stage (285) is activated before the retaining arm (30) is loaded.

[0276] 74. An apparatus according to any one of embodiments 71 to 73, wherein the no-load correction stage (285) is activated after the retaining arm (30) moves into the working position.

[0277] 75. An apparatus according to any one of embodiments 40 to 74, wherein each deformation value (D) applied by the load analysis stage (233) is corrected by a tilt correction stage (283), which is associated with the deformation value (D) of the orientation of the retaining arm (30) when the vehicle is stationary on a horizontal reference surface, correcting the actual orientation of the retaining arm (30) due to the tilt of the vehicle.

[0278] 76. An apparatus according to embodiment 75, wherein the tilt correction stage (283) changes the deformation value (D) of the deformation zone (152, 154, 156, 158) in such a way that, in the deformation zone, the influence of the changed orientation of the retaining arm (30) relative to the orientation of the vehicle at rest on a horizontal reference surface is taken into account.

[0279] 77. An apparatus according to embodiment 75 or 76, wherein the tilt correction stage (283) operates with a stored tilt correction value.

[0280] 78. An apparatus according to embodiment 77, wherein the tilt correction stage (283) operates with an experimentally determined tilt correction value.

[0281] 79. An apparatus according to the preamble of embodiment 40 or according to any one of embodiments 40 to 78, wherein at least two deformation sensors (172, 174, 176, 178) of the sensor assembly (170) are arranged on the same side of the neutral fiber of the retaining arm (30), and the length of the neutral fiber is not variable when the retaining arm (30) is bent and deformed.

[0282] 80. An apparatus according to embodiment 79, wherein a force detection module (100) is arranged on one side of the retaining arm (30, 30'), which includes a sensor assembly (170), which detects the force applied to the connecting element (40) during operation and transmitted from the retaining arm (30) to the motor vehicle body (12).

[0283] 81. A device according to embodiment 80, wherein the sensor assembly has at least three, in particular four deformation sensors (172, 174, 176).

[0284] 82. A device according to embodiments 80 to or 81, wherein the force detection module (100) is arranged on a side of the retaining arm (30, 30') facing the roadway (44) in an operating state.

[0285] 83. A device according to any one of embodiments 80 to 82, wherein the force detection module (100) is arranged on a side of the retaining arm (30, 30') facing away from the roadway (44) in the operating state.

[0286] 84. An apparatus according to the preamble of embodiment 40 or any one of embodiments 40 to 83, wherein the force applied to the connecting element (40) during operation and transmitted by the retaining arm (30) to the motor vehicle body (12) is detected by an evaluation and analysis unit (230) having a sensor assembly (170), the sensor assembly having at least two deformation sensors (172, 174, 176), and the deformation sensors (172, 174, 176, 178) are arranged on at least one deformation transfer element (102) connected to the retaining arm (30).

[0287] 85. An apparatus according to the preamble of embodiment 40 or any one of embodiments 40 to 84, wherein the force applied to the connecting element (40) during operation and transmitted by the retaining arm (30) to the motor vehicle body (12) is detected by an evaluation and analysis unit (230) having a sensor assembly (170), the sensor assembly having at least two deformation sensors (172, 174, 176), and all deformation sensors (172, 174, 176, 178) of the sensor assembly (170) are arranged on a common deformation transfer element (102).

[0288] 86. An apparatus according to any one of embodiments 79 to 85, wherein each of the at least two deformation sensors (172, 174, 176) detects deformations of different sizes of the retaining arm (30, 30') when one and the same force affects the connecting element (40).

[0289] 87. An apparatus according to any one of embodiments 79 to 86, wherein the deformation transfer element (102) has no relative movement and is thereby rigidly connected to the retaining arm (30) in at least two fixed areas (104, 106, 108), and at least one of the deformation sensors (172, 174, 176, 178) is arranged between the fixed areas (104, 106, 108) of the deformation transfer element (102).

[0290] 88. An apparatus according to any one of embodiments 79 to 87, wherein the deformation transfer element (102) is connected to the retaining arm (30) by means of at least three fixed areas (104, 106, 108), and at least one of the deformation sensors (172, 174, 176, 178) is arranged between two fixed areas of each fixed area (104, 106, 108).

[0291] 89. An apparatus according to any one of embodiments 79 to 88, wherein the deformation transfer element (102) is connected to the retaining arm (30) in the fixing area (104, 106, 108) by means of a coupling element (114, 116, 118).

[0292] 90. A device according to embodiment 89, wherein the coupling element (114, 116, 118) is rigidly connected to the retaining arm (30) on the one hand, and is rigidly connected to the fixing area (104, 106, 108) of the deformation transfer element (102) on the other hand.

[0293] 91. A device according to embodiment 90, wherein the engaging element (114, 116, 118) is formed on the retaining arm.

[0294] 92. An apparatus according to any one of embodiments 79 to 91, wherein the coupling elements (114, 116, 118) transfer the deformation of the retaining arm (30) in the deformation regions (82, 84) of the retaining arm (30), respectively, located between the coupling elements (114, 116, 118) to the fixing regions (104, 106, 108) of the deformation transfer element (102).

[0295] 93. A device according to any one of embodiments 89 to 92, wherein a deformation region (82, 84) of the retaining arm (30) is present between two engagement elements (114, 116, 118), respectively.

[0296] 94. An apparatus according to any one of embodiments 79 to 93, wherein the retaining arm (30) has at least two deformation regions (82, 84), and the deformation of the deformation regions is transferred to the fixed regions (104, 106, 108) of the deformation transfer element (102) through coupling elements (114, 116, 118) arranged on both sides of each deformation region (82, 84), and there is a deformed region (152, 154, 156) of the deformation transfer element (102) between the fixed regions.

[0297] 95. A device according to embodiment 94, wherein the at least two deformation regions (82, 84) are arranged successively in the extension direction of the retaining arm (30).

[0298] 96. An apparatus according to any one of embodiments 79 to 95, wherein at least one deformation sensor (172, 174, 176, 178) is arranged in a deformed area of ​​the deformation transfer element (102).

[0299] 97. An apparatus according to any one of embodiments 94 to 96, wherein each deformable region (152, 154, 156, 158) is connected to a non-deformable region (144, 146, 148) of the deformation transfer element (102), and the fixed regions (104, 106, 108) are respectively located in a non-deformable region (144, 146, 148).

[0300] 98. A device according to embodiment 97, wherein the deformed regions (152, 154, 156, 158) are respectively arranged between two non-deformable regions (144, 146, 148).

[0301] 99. An apparatus according to embodiments 97 or 98, wherein the regions (144, 146, 148) that are not easily deformed and the regions (152, 154, 156, 158) that are deformed are arranged successively in the deformation direction.

[0302] 100. An apparatus according to any one of embodiments 94 to 99, wherein the deformed region (152, 154, 156, 158) is constructed as a deformation concentrated region.

[0303] 101. An apparatus according to any one of embodiments 79 to 100, wherein, outside the deformed area (152, 154, 156, 158), the material of the deformation transfer element (102) is constructed as a material that is not easily deformed or a material that is not actively deformed.

[0304] 102. An apparatus according to any one of embodiments 79 to 101, wherein, in the deformed region (152, 154, 156, 158), the material of the deformation transfer element (102) tends to deform by configuration, for example by narrowing of the cross section.

[0305] 103. An apparatus according to any one of embodiments 79 to 102, wherein the deformation transfer element (102) has non-deformed areas (192, 194, 196, 198) in addition to the deformed areas (152, 154, 156, 158), and at least one reference deformation sensor (182, 184, 186, 188) is arranged on the non-deformed areas (192, 194, 196, 198).

[0306] 104. An apparatus according to embodiment 103, wherein each of the non-deformed regions (192, 194, 196, 198) is made of the same material as the deformed regions (152, 154, 156, 158).

[0307] 105. A device according to embodiments 103 or 104, wherein each of the non-deformed regions (192, 194, 196, 198) is connected on one side to a non-deformable region (144, 146, 148) of the deformation transfer element (102).

[0308] 106. A device according to any one of embodiments 103 to 105, wherein the deformation-free area (192, 194, 196, 198) of the deformation transfer element (102) is constructed in a tongue shape.

[0309] 107. An apparatus according to any one of embodiments 103 to 106, wherein the non-deformed regions (192, 194, 196, 198) of the deformation transfer element (102) are made of the same material as the deformed regions (152, 154, 156, 158), and in particular have the same material thickness.

[0310] 108. A device according to embodiments 103 to 107, wherein the reference deformation sensor (182, 184, 186, 188) is thermally connected to the deformation transfer element (102).

[0311] 109. An apparatus according to embodiment 108, wherein the reference deformation sensor (182, 184, 186, 188) is thermally connected to the deformation sensor (172, 174, 176, 178) by means of the deformation transfer element (102).

[0312] 110. An apparatus according to embodiment 109, wherein, in order to achieve optimal thermal connection between each of the deformation sensors (172, 174, 176, 178) and a reference deformation sensor (182, 184, 186, 188) assigned to the deformation sensor, each deformed region (152, 154, 156, 158) equipped with a deformation sensor (172, 174, 176, 178) is thermally connected to a non-deformed region (192, 194, 196, 198) assigned to the deformed region, and the non-deformed region carries the assigned reference deformation sensor (182, 184, 186, 188).

[0313] 111. An apparatus according to any one of embodiments 103 to 110, wherein the non-deformed region (192, 194, 196, 198) carrying each reference deformation sensor (182, 184, 186, 188) has the same thermal properties as the deformed region (152, 154, 156, 158), and the deformed region (152, 154, 156, 158) carries the corresponding deformation sensor (172, 174, 176, 178).

[0314] 112. An apparatus according to any one of embodiments 103 to 111, wherein each of the non-deformed regions (192, 194, 196, 198) carrying the reference deformation sensors (182, 184, 186, 188) has a similar geometry to the deformed regions (152, 154, 156, 158) carrying the deformation sensors (172, 174, 176, 178).

[0315] 113. An apparatus according to any one of embodiments 103 to 112, wherein the non-deformed regions (192, 194, 196, 198) of the deformation transfer element (102) are made of the same material as the deformed regions (152, 154, 156, 158) of the deformation transfer element (102).

[0316] 114. An apparatus according to any one of embodiments 103 to 113, wherein at least one temperature sensor (252, 254, 256, 258) for functional monitoring is assigned to the reference deformation sensor (182, 184, 186, 188).

[0317] 115. An apparatus according to any one of embodiments 79 to 114, wherein the deformation transfer element (102) is constructed similarly to a plate, and each deformed area (152, 154, 156, 158) carrying a deformation sensor (172, 174, 176, 178) is constructed by a cross-sectional narrowing portion of the deformation transfer element (102).

[0318] 116. A device according to embodiment 115, wherein the cross-sectional narrowing portion of the deformation transfer element (102) is constructed by narrowing the surface area of ​​the deformation transfer element (102).

[0319] 117. An apparatus according to any one of embodiments 79 to 116, wherein the deformation sensor and the reference deformation sensor are constructed as strain sensors, in particular as strain gauges.

[0320] 118. An apparatus according to any one of embodiments 79 to 117, wherein the deformation sensor and the reference deformation sensor are constructed as magnetostrictive sensors or optical sensors.

[0321] 119. A device according to the preamble of embodiment 40 or any one of embodiments 40 to 118, wherein the retaining arm (30) has a first deformation region (82) and a second deformation region (84) between the first end (32) and the second end (34), and when there is a force (Fx) acting in the longitudinal middle plane (18) of the retaining arm (30) parallel to the travel direction (24), the deformation regions are deformed respectively, and the deformation is different from the deformation when there is a force (Fx) acting in the longitudinal middle plane (18) transverse to the travel direction (24). z ) when the deformation occurs is different.

[0322] 120. A device according to embodiment 119, wherein when there is a force (F y ), the first deformation region and the second deformation region (82, 84) are deformed respectively, and the deformation is related to the presence of a force (F) acting parallel to and / or transverse to the travel direction (24) and in the longitudinal midplane (18). x , F2) when the deformation is different.

[0323] 121. An apparatus according to embodiments 119 or 120, wherein the first deformation region and the second deformation region (82, 84) are arranged successively in the extension direction of the retaining arm (30).

[0324] 122. An apparatus according to any one of embodiments 40 to 121, wherein each deformation sensor (172, 174, 176, 178) is connected to an associated reference deformation sensor (182, 184, 186, 188) in a Wheatstone bridge.

[0325] 123. An apparatus according to any one of embodiments 40 to 122, wherein the evaluation and analysis unit (230) has a processor (234) that converts the numerical value corresponding to the deformation in the deformed area (152, 154, 156, 158) into a force (F) acting on the connecting element (40) in three mutually transverse, especially mutually perpendicular spatial directions using a conversion value. x 、F y , F2) of the corresponding values ​​(WFx, WFy, WFz), the converted values ​​are obtained by calibration and stored in the memory (236).

[0326] 124. A device according to any one of embodiments 40 to 122, wherein two forces (F x 、F z ), in particular two forces (F x 、F z ), but are transverse to each other, especially perpendicular to each other, and the third force (F y ) is transverse to the longitudinal middle plane (18) of the retaining arm (30), in particular perpendicular to the longitudinal middle plane (18) of the retaining arm (30).

[0327] 125. An apparatus according to embodiments 123 or 124, wherein converted numerical values ​​for force combinations acting on the connecting element (40) in different eight partitions are stored in the memory (236).

[0328] 126. An apparatus according to any one of embodiments 40 to 125, wherein, in order to determine deformation, the evaluation and analysis unit (230) detects the values ​​of the deformation sensors (172, 174, 176, 178) and in particular detects the values ​​of the reference deformation sensors (182, 184, 186, 188).

[0329] 127. An apparatus according to embodiment 126, wherein the evaluation and analysis unit (230) detects the value of at least one temperature sensor (252, 254, 256, 258) for functional detection of the reference deformation sensor (182, 184, 186, 188).

[0330] 128. An apparatus according to implementation scheme 127, wherein the evaluation and analysis unit (230) detects the values ​​of the temperature sensors respectively assigned to each reference deformation sensor.

[0331] 129. A device according to any one of embodiments 40 to 128, wherein the retaining arm (30) carries the connecting element (40) at its second end (34).

[0332] 130. A device according to embodiment 129, wherein the retaining arm (30) and the connecting element (40) constitute connected parts.

[0333] 131. A device according to embodiment 129 or 130, wherein the retaining arm (30) is configured as a ball neck and carries the connecting element (40) on the second end (34), the connecting element including a connecting ball portion (43).

[0334] 132. A device according to any one of embodiments 40 to 131, wherein the retaining arm (30') includes a receiving body (31') so as to detachably receive the connecting element (40').

[0335] 133. A device according to embodiment 132, wherein the receiving body (31') has an insertion receiving portion (33') which is accessible through an insertion opening (35').

[0336] 134. A device according to embodiment 132 or 133, wherein the connecting element (40') comprises a carrying arm (42').

[0337] 135. A device according to any one of embodiments 132 to 134, wherein the support arm (42') having the insertion section (45') can be inserted and fixed in the insertion receptacle (33').

[0338] 136. A device according to any one of embodiments 132 to 135, wherein the carrying arm (42') carries a connecting ball portion (43).

[0339] 137. A device according to embodiments 135 or 136, wherein the insertion section (45') is received in the insertion receptacle (33') in a form-locking manner transversely in the insertion direction (E) and is fixed in the functional state along the insertion direction by a form-locking body (41).

[0340] 138. An apparatus according to the preamble of embodiment 40 or any one of embodiments 40 to 137, wherein the retaining arm (30) is equipped with at least three deformation sensors (172, 174, 176, 178), which react in particular in different ways to three forces acting on the connecting element (40) in spatial directions transverse to each other, and the at least three deformation sensors (172, 174, 176, 178) send sensor values ​​(M), and at least one component force acting on the connecting element (40) is derived from the sensor values ​​with the aid of an evaluation and analysis unit (270).

[0341] 139. The device according to any one of embodiments 40 to 138, wherein the evaluation and analysis unit (230) obtains the value (WF) of the component force in the spatial direction (x, y, z) x , W.F. y , W.F. z )

[0342] 140. The device according to any one of embodiments 40 to 139, wherein the evaluation unit (270) obtains the value (WF z ).

[0343] 141. A device according to any one of embodiments 40 to 140, wherein the evaluation and analysis unit (230) obtains the value (F) of its component force in the driving direction of the motor vehicle (10). x ).

[0344] 142. A device according to any one of embodiments 40 to 141, wherein the evaluation unit (230) determines the value (F) of its component force transverse to, in particular perpendicular to, the vertical longitudinal midplane (18). y ). BRIEF DESCRIPTION OF THE DRAWINGS

[0345] In the figure:

[0346] Figure 1 A side view showing a portion of the rear part of a motor vehicle body according to a first embodiment of the device for connecting a trailer according to the invention;

[0347] Figure 2 The motor vehicle body is shown Figure 1 The rear view looking in the direction of the arrow X;

[0348] Figure 3 Show according to Figure 2 A first embodiment of a device for connecting a trailer or a load-bearing member in its working position;

[0349] Figure 4 A first exemplary embodiment of a device for connecting a trailer or a load-bearing member is shown in a rest position R;

[0350] Figure 5 A side view of the holding arm of the first embodiment is shown, and a load force F is x Schematic diagram of a connecting element;

[0351] Figure 6 Shown in Figure 5 A top view of the retaining arm viewed in the direction of arrow D;

[0352] Figure 7 Shown in a powerful F z Side view of the holding arm at impact;

[0353] Figure 8 Shown in a powerful F z The basis of influence Figure 6 A top view of a retaining arm;

[0354] Fig. 9 Shown in a powerful F y Side view of the holding arm at impact;

[0355] Fig.10 Shown in a powerful F y Similar to the impact Figure 6 A top view of

[0356] Fig.11 Shown along Figure 5 A cross-sectional view taken along line 11-11 in FIG.

[0357] Fig.12 Shown in the light of Figure 5 and Figure 6 The force F x An enlarged top view of the holding arm with the deformation transmission element during impact;

[0358] Fig.13 Shown in the light of Figure 7 and Figure 8 The force F z The basis of influence Fig.12 A top view of

[0359] Fig.14 Shown in the light of Fig. 9 and Fig.10 The force F y A top view similar to 12 at the time of impact;

[0360] Fig.15shows an enlarged top view of a deformation transmission element according to a first exemplary embodiment, the deformation transmission element having a deformation sensor and a reference deformation sensor arranged thereon;

[0361] Fig.16 A Wheatstone bridge is shown for connecting the first deformation sensor and the first reference deformation sensor;

[0362] Fig.17 The method for connecting the second deformation sensor and the second reference deformation sensor is shown according to Fig.16 The Wheatstone bridge;

[0363] Fig.18 The method for connecting the third deformation sensor and the third reference deformation sensor is shown according to Fig.16 The Wheatstone bridge;

[0364] Fig.19 The method for connecting the fourth deformation sensor and the fourth reference deformation sensor is shown according to Fig.16 The Wheatstone bridge;

[0365] Fig. 20 An analysis circuit is shown, which is used to process Figures 16 to 19 The voltage measured in the Wheatstone bridge circuit;

[0366] Fig.21 shows a connecting element 40 and a force acting on the connecting element 40 obtained by the evaluation circuit;

[0367] Fig. 22 A side view of a first exemplary embodiment and a diagram of a circuit board carrying an evaluation circuit are shown;

[0368] Fig.23 A unit consisting of a printed circuit board carrying an evaluation circuit and a deformation transmission element having a deformation sensor and a reference deformation sensor is shown in a side view;

[0369] Fig.24 A second exemplary embodiment of the device according to the invention with an inverse unit arrangement is shown, comprising a deformation transmission element, a strain sensor, a reference strain sensor and an evaluation unit;

[0370] Fig.25 It is shown that according to the present invention, Fig.23 A diagram of a third embodiment of a similar device and a temperature sensor additionally provided on the circuit board;

[0371] Fig.26 A fourth exemplary embodiment of the device according to the invention is shown together with a diagram of a deformation transmission element and a diagram of a temperature sensor additionally arranged on the deformation transmission element;

[0372] Fig. 27 Shows something like Fig. 20 an evaluation analysis unit according to the third or fourth embodiment;

[0373] Fig.28 A fifth embodiment of the device according to the invention is shown similar to Figure 1 Side view of

[0374] Fig.29 A perspective view showing a fifth embodiment of the device according to the invention in the working position;

[0375] Fig.30 Shows the working position, Fig.28 A diagram of the fifth embodiment viewed in the direction of arrow X′;

[0376] Fig.31 Shown along Fig.30 A cross-sectional view taken along line 31-31 in FIG.

[0377] Fig.32 Shown along Fig.30 A cross-sectional view taken along line 32-32 in FIG.

[0378] Fig.33 Similar to the embodiment showing the static position Fig.31 sectional view of;

[0379] Fig.34 Shown in Fig.33 A perspective view of the fifth embodiment in a static position, viewed in the direction of arrow Y′;

[0380] Fig.35 A side view of the holding arm of the fifth embodiment is shown, and a load force F is x Schematic diagram of a connecting element;

[0381] Fig.36 Shown in Fig.35 A top view of the retaining arm viewed in the direction of the middle arrow D′;

[0382] Fig.37 Shown in a powerful F z A side view of the retaining arm of the fifth embodiment during impact;

[0383] Fig.38 Shown in a powerful F z The basis of influence Fig.36 A top view of a retaining arm;

[0384] Fig.39 Shown in a powerful F y A side view of the retaining arm of the fifth embodiment during impact;

[0385] Fig.40Shown in a powerful F y Similar to the impact Fig.36 A top view of

[0386] Fig.41 A first approach to mathematically linking the magnitude of the force component to the sensor value is shown;

[0387] Fig.42 A schematic view showing the procedure when calibrating the holding arm;

[0388] Fig.43 A second approach to mathematically linking the magnitude of the force component to the sensor value is shown;

[0389] Fig.44 shows the calibration based on the force components in the octaves with the aid of the connecting element as the midpoint;

[0390] Fig.45 A schematic diagram of the evaluation unit and its interaction with other components is shown;

[0391] Fig.46 For example, a motor vehicle with a trailer is shown;

[0392] Fig.47 A motor vehicle with a bicycle carrier is shown;

[0393] Fig.48 shows deformation values ​​measured by two deformation sensors in each deformation region when a towing member is present, the deformation sensors being arranged on opposite sides of the longitudinal center plane;

[0394] Fig.49 shows the deformation values ​​measured by two deformation sensors per deformation region when a bicycle carrier is present, the deformation sensors being arranged on opposite sides of the longitudinal center plane;

[0395] Fig.50 shows the deformation values ​​measured and averaged for each deformation zone when a trailer is present;

[0396] Fig.51 shows the measured and averaged deformation values ​​for each deformation zone when a bicycle carrier is present;

[0397] Fig.52 shows deformation values ​​detected in a time-resolved manner by two deformation sensors per deformation region in each case when a pulse-like influence is present on the trailer vehicle, the deformation sensors being arranged on opposite sides of a longitudinal center plane; and

[0398] Fig.53 The figures show the deformation values ​​detected in a time-resolved manner by two deformation sensors per deformation region in each case when there is a rolling motion of the trailer vehicle, the deformation sensors being arranged on opposite sides of the longitudinal center plane. DETAILED DESCRIPTION

[0399] The motor vehicle, designated as a whole by 10 , comprises a motor vehicle body 12 which is provided in a rear region 14 and in the vicinity of a vehicle underbody 16 with a carrier unit 20 which has, for example, a transverse carrier 22 which is connected to the rear region 14 adjacent to the vehicle underbody 16 .

[0400] The connection between the transverse support 22 and the rear region 14 can be achieved, for example, via a mounting flange that rests on the rear region 14 or, for example, via a side support 26 that extends in the vehicle longitudinal direction 24 and rests on a body section 28 that also extends in the vehicle longitudinal direction 24 .

[0401] A holding arm, in particular a ball neck, designated as a whole by 30 is connected to the support unit 20 by holding a first end 32 of the holding arm 30 on the support unit 20 , preferably on the transverse support 22 , either directly or via a bearing unit 36 ​​.

[0402] The holding arm 30 carries a connecting element 40 at a second end 34 opposite the first end 32 , which connecting element is provided, for example, for towing a trailer or for fastening a load-carrying unit.

[0403] For example, such a connecting element 40 is designed as a connecting ball 43 which allows a very common connection by means of a towing ball joint of a trailer vehicle.

[0404] However, the connecting ball 43 also allows a simple mounting of the load-bearing unit, since very common load-bearing units can also be mounted on the connecting ball and, if necessary, can also be additionally supported on the retaining arm 30 .

[0405] The connecting element 40 is located, for example, on a supporting part 42 which is connected to the second end region 34 of the retaining arm 30 and extends from the side of the supporting part 42 facing away from the roadway 44 in the direction of a center axis 46 which extends approximately vertically when the roadway 44 is horizontal and, when a connecting ball 43 is present, extends through a ball center point 48.

[0406] To improve the aesthetic effect, the transverse support 22 is preferably arranged below a bumper unit 50 at the rear of the motor vehicle body 12 , wherein the bumper unit 50 covers the transverse support 22 and the first end 32 of the retaining arm 30 , for example.

[0407] The holding arm 30 carries the connecting element 40, which is designed as a connecting ball, in particular in the exemplary embodiment shown, wherein the holding arm 30 carries the connecting element 40, which is designed as a connecting ball, in particular as in Figures 1 to 3 As in , the holding arm 30 extends from the pivot bearing unit 36 ​​to which the holding arm 30 is connected at its first end region 32 , wherein a pivot bearing body 52 of the pivot bearing unit 36 ​​is integrally formed on the first end region 32 , for example.

[0408] The pivot bearing body 52 of the pivot bearing unit 36 ​​can be pivotally supported about a pivot axis 54 on a pivot bearing receptacle 56, wherein the pivot axis particularly extends obliquely to the vertical vehicle longitudinal center plane 18, and the pivot bearing receptacle 56 on the one hand rotatably guides the pivot bearing body 52 about the pivot axis 54 and on the other hand comprises a locking unit (not shown) which allows the retaining arm 30 to be fixed in a non-rotatable manner relative to a pivoting movement about the pivot axis 54 in the working position and the rest position.

[0409] The pivot bearing receptacle 56 is in turn fixedly connected on its side to the transverse support 22 via a pivot bearing base 58 .

[0410] like Figures 1 to 4 As shown, the retaining arm 30 in this embodiment can be Figures 1 to 3 The working position A shown in FIG. is pivoted into Figure 4 In the rest position R shown in FIG. 1 , the connecting element constructed as a connecting ball 40 is in the working position so that the connecting element is behind the bumper unit 50 and on the side facing away from the roadway 44 , and the connecting element 40 is arranged to face the roadway 44 in the rest position.

[0411] In this case, the connecting element 40 can be displaced in a shuttle manner below the lower edge 51 of the bumper unit 50 .

[0412] Here, the retaining arm 30 in the working position A extends in particular essentially in a vertical vehicle longitudinal center plane 18 , wherein, when the connecting element 40 is configured as a connecting ball, the connecting element intersects the vehicle longitudinal center plane 18 centrally, so that in the working position A, the vertical ball center axis 48 is located in the longitudinal center plane 18 .

[0413] In the illustrated embodiment, the retaining arm 30 extends from the first end region 32 with a first arc segment 62 to an intermediate piece 64, the intermediate piece extends to an annular body 66, and a second arc segment 68 located on the side opposite to the intermediate piece 64 and the arc segment 62 is connected to the annular body, the second arc segment carrying a connecting element 40 constructed as a connecting ball on that side, wherein a ball attachment part 42 is also provided between the connecting element 40 constructed as a connecting ball and the second arc segment 148.

[0414] The second arc segment 68 forms the end region 34 of the holding arm 30 , which carries, for example, the ball attachment 42 , to which the connecting element 40 , which is designed as a connecting ball, adjoins.

[0415] Especially Figure 4 and Figure 5 The annular body 66 is shown to be provided for simple mounting of a contact unit on the holding arm 30 behind the intermediate piece 64 , said annular body surrounding a passage 72 into which the contact unit can be mounted.

[0416] The annular body 66 is preferably arranged in this case such that a transition to the second arc segment 68 follows the annular body 66 .

[0417] By means of the first arc segment 62, the intermediate piece 64 and the second arc segment 68, the retaining arm 30 constructed in this way is approximately U-shaped and oriented in the working position A so that the forces acting on the connecting element 40, in particular the forces acting on the ball center point 46, are transmitted to the pivot bearing body 52 of the pivot bearing unit 36 ​​via the approximately U-shaped configuration of the retaining arm 30, wherein the pivot axis 54 represents the center of the force receiving portion through the pivot bearing unit 36, and a load on the connecting element 40 occurs in the working position A and is to be detected.

[0418] like Figures 1 to 8 As shown, forces acting on the connecting element 40 are transmitted via the retaining arm 30 to the bearing unit 36 ​​and from the latter to the carrier unit 20 , which subsequently directs the forces into the rear region 14 of the motor vehicle body 12 , wherein different regions of the retaining arm 30 are used to detect the forces acting on the connecting element 40 .

[0419] In the above-mentioned embodiment, the first deformation region 82 and the second deformation region of the holding arm 30 are used as examples. The first deformation region includes a section of the intermediate piece 64 and the annular body 66 , and the second deformation region includes a section of the annular body 66 and the second arc segment 68 .

[0420] Furthermore, based on this exemplary embodiment, the annular region 66 has a high stability with respect to bending forces in the longitudinal center plane 18 , also transversely thereto, and in particular also has sufficient rigidity against tensile loads.

[0421] Thus, for example, Figure 5 and Figure 6 The force F shown in x So that in the deformation areas 82, 84, on the one hand, tensile forces ZX1, ZX2 ( Figure 6 ) and / or the occurrence of bending forces BX1, BX2 ( Figure 5 ), wherein these forces act in the direction of the longitudinal middle plane 18 of the holding arm 30, in particular in the longitudinal middle plane 18, the force F x In longitudinal center plane 18 it extends, in particular, in the longitudinal direction of the vehicle and is oriented, for example, perpendicularly to center axis 46 and facing away from pivot bearing 52 .

[0422] Furthermore, in the deformation regions 82, 84, as Figure 7 , Figure 8 As shown, when the connecting element 40 is loaded with a force F acting in the vertical direction, especially in the direction of gravity, z In the deformation regions 82, 84, bending forces BZ1, BZ2 occur mainly, wherein these forces act in a direction parallel to the longitudinal center plane 18 of the holding arm 30, in particular in the longitudinal center plane 18, and thus have opposite effects on mutually opposite surfaces with respect to the so-called neutral fibers NF of invariable length. z For example, when the vehicle is on a substantially horizontal plane, it acts in the direction of the center axis.

[0423] Preferably, the deformation regions 82 and 84 are arranged on the holding arm 30 and / or the holding arm is designed in the deformation regions 82, 84 in such a way that a force F acting in the direction of gravity or in a direction opposite to the direction of gravity is present. z When the retaining arm 30 is deformed, deformations of different strengths occur.

[0424] It is particularly useful, as will be explained in detail below, for the force F acting in the vertical direction to z The deformation region 84 causes a significantly smaller deformation than the deformation region 82, and when there are approximately equal forces F x +F z When the combined force is , the deformations in the two deformation regions 82 and 84 are approximately similar in size.

[0425] Therefore, the deformation area 82 is highly sensitive to the support load, and the deformation area 82 is less sensitive to the support load.

[0426] In addition, if Fig. 9 , Fig.10 As shown, the force F acting on the connecting element 40 and oriented perpendicularly to the longitudinal center plane 18 and the center axis 46 y Bending forces BY1 , BY2 are brought about which act in opposite directions on both sides of the longitudinal center plane 18 , but on different sides of the longitudinal center plane.

[0427] In order to detect these tensile forces ZX1 , ZX2 and bending forces BX1 , BX2 , BZ1 , BZ2 , BY1 , BY2 , a force detection module, designated as a whole by 100 , is provided on the holding arm 30 .

[0428] The force detection module 100 includes a deformation transfer element 102, which is rigidly connected to the retaining arm 30 in three fixing areas 104, 106, and 108, wherein the fixing area 104 is located on the side facing the first end 32 and is rigidly connected to an additional part 114 of the retaining arm 30, for example, located on the middle part 64, the fixing area 106 is approximately located in the middle between the fixing areas 104, 108 and is connected to, for example, a retaining additional part 116 located on the annular body 66, in particular in the center of the annular body 66, and the fixing area 108 is connected to an additional part 118 of the retaining arm 30 arranged on the arc segment 68, for example, in the central area of ​​the arc segment 68 between the annular body 66 and the end 34.

[0429] The connection between the engagement elements 114 , 116 , 118 of the holding arm 30 is hereby rigid and free of play and is preferably realized by welding or gluing, which does not allow for any elasticity of movement between the deformation transmission element 102 and the engagement elements 114 , 116 , 118 .

[0430] The engagement elements 114 , 116 , 118 are preferably likewise rigidly connected to the holding arm, in particular are integrally formed on the holding arm.

[0431] like Fig.11 As shown exemplarily with respect to the additional part 114, the coupling elements 114, 116, 118 of the retaining arm 30 are preferably constructed so that they have a base area 122, which extends from the retaining arm 30 and constructs a fixing bolt 124, which passes through a notch 126 arranged in the respective fixing area, in this case in the fixing area 104 of the deformation transfer element 102.

[0432] The fixing bolt 124 and the recess 126 are preferably shaped such that they can be rigidly connected via a weld seam 128 .

[0433] Furthermore, the foot region 122 is designed such that it has a shoulder 132 which is formed annularly around the fixing bolt 124 and on which the deformation transmission element 102 rests with a bearing surface 134 of the fixing region 104 surrounding the recess 126 and is thereby supported, for example, when the weld seam 128 is attached.

[0434] Furthermore, the deformation transmission element 102 is designed such that it has non-deformable regions 144, 146, 148, which in particular include the fixing region 104, and deformable regions 152, 154, 156, 158, respectively, which are arranged between the non-deformable regions 144, 146, 148, wherein the deformable regions 152, 154 are, for example, located between the non-deformable regions 144, 146, the deformable regions 152, 154 are preferably arranged at the same distance from the longitudinal center plane 18, but on opposite sides of the longitudinal center plane, and the deformable regions 156, 158 are located between the non-deformable regions 146, 148, and the deformable regions 156, 158 are likewise respectively arranged on opposite sides of the longitudinal center plane 18, preferably at the same distance from the longitudinal center plane.

[0435] In this case, the deformed regions 152 to 158 are preferably designed as deformation-concentrating regions, which means that deformations influencing the deformation transmission element 102 act significantly more strongly in the deformation-concentrating regions 152 , 154 , 156 , 158 than in the less deformable regions 144 , 146 , 148 .

[0436] The formation of such a deformation concentration region can be achieved in the simplest case by making the material in the deformation concentration regions 152 to 158 less rigid than the less deformable regions 144 , 146 , 148 .

[0437] The modification with respect to the rigidity can be achieved, for example, by changing the material in the deformation concentration regions 152 , 154 , 156 , 158 or likewise by changing the effective material cross section.

[0438] In accordance with Figure 6 , Figure 8 , Fig.10 In the exemplary embodiment shown, deformation concentration regions 152 , 154 , 156 , 158 are designed as narrow connecting strips of a plate 162 which forms deformation transmission element 102 , while less deformable regions 144 , 146 , 148 are formed by wider regions of plate 162 .

[0439] The result of such a construction of the deformation transfer element 102 is that the deformation of the deformation region 82 of the retaining arm 30 causes the coupling elements 114, 116 rigidly connected to the retaining arm 30 to move relative to each other, and the relative movement is transmitted to the fixing regions 104, 106, and from the fixing regions to the non-deformable regions 144, 146 of the deformation transfer element 102, wherein the non-deformable regions 144, 146 of the deformation transfer element 102 are basically not deformed, and thus the entire deformation generated in the deformation region 82 is transmitted to the deformed regions 152, 154, and the deformed regions, which are also constructed as deformation concentration regions, thereby concentrate the entire deformation formed between the coupling elements 114, 116 in the deformation region 82.

[0440] This indicates that the deformation concentration areas 152, 154 undergo deformation caused by the bending force BX1 acting in the longitudinal middle plane 18, as well as deformation caused by the tensile force ZX1, forces BZ1, and BZ2, wherein, when the retaining arm 30 is constructed symmetrically with respect to the longitudinal middle plane 18, the two deformation concentration areas 152, 154 undergo approximately the same deformation, because these deformations are based on the forces acting basically in the longitudinal middle plane 18.

[0441] This is appearing Fig. 9 , Fig.10 In the case of the bending force BY1 shown, the bending force BY1 acts on different sides of the longitudinal middle plane 18 in different directions, so that the deformation concentration area 152 is based on Fig. 9 , Fig.10 The deformation occurs due to the bending force BY1 shown in FIG. 1 , which is based on a compressive load, while the deformation concentrated area 154 is deformed based on a tensile load.

[0442] The deformation of the deformation region 84 of the retaining arm is transmitted in a similar manner via the joining elements 116, 118 to the fixing regions 106, 108, which are parts of the less deformable regions 146, 148, and thus transmit the deformation of the deformation region 84 to the deformable regions 156, 158, which are also constructed as deformation concentration regions and thus the entire deformation of the deformation region 84 occurs.

[0443] This also means that all forces BX2, ZX2, BZ2 acting basically in the longitudinal middle plane 18 affect the deformation concentration areas 156, 158 in the same way when the retaining arm 30 is constructed symmetrically with respect to the longitudinal middle plane 18, while the force BY2 causes opposite deformations in the deformation areas 156, 158, so that, for example, the deformation in the deformation concentration area 156 is based on a compressive load, while the deformation in the deformation concentration area 158 is based on a tensile load.

[0444] The deformation regions 82, 84 of the holding arms are such that a force F x The resulting load on the connecting element 40 causes a deformation which is different from the deformation caused by the force F z The resulting deformation of the connecting element 40 under load can be identified by means of the different deformations occurring in the deformation concentration areas 152 , 154 or in the deformation concentration areas 156 , 158 based on the different deformations of the deformation areas 82 , 84 . x or force F z Whether the connecting element 40 is influenced as explained in detail below.

[0445] For example, this can be illustrated by Fig.12 As shown for the sake of simplicity, when the deformation areas 82, 84 behave in substantially the same manner when the bending forces BX1, BX2 combined with the occurring tensile forces ZX1, ZX2 occur, then the deformation D152 in the deformation concentration area 152, the deformation D154 in the deformation concentration area 154, the deformation D156 in the deformation concentration area 156, and the deformation D158 in the deformation concentration area 158 are substantially the same size.

[0446] In addition, when the force F z When the deformation performance in the deformation regions 82 and 84 can change, Fig.13 As exemplarily shown in FIG. 1 , the deformation D152 , D154 in the deformation concentration regions 152 , 154 may be significantly smaller than the deformation D156 , D158 in the deformation concentration regions 156 , 158 .

[0447] like Fig.14 As shown, under the force F y The situation will be different when the impact occurs.

[0448] In this case, compression occurs in the deformation concentrated regions 152 , 156 as deformation D152 , D156 , while extension occurs in the deformation concentrated regions 154 , 158 as deformation D154 , D158 , respectively.

[0449] Here, deformations D152 , D156 based on compression may be the same or different, and deformations D154 , D158 based on extension may also be the same or different in the same manner.

[0450] like Fig.15 As shown, in order to detect the force F x and / or F2 and / or F y The resulting extension or compression in the deformation concentration areas 152 , 154 , 156 , 158 , deformation sensors 172 , 174 , 176 , 178 are respectively provided in the deformation concentration areas 152 , 154 , 156 , 158 , and the extension and compression in each deformation concentration area 152 , 154 , 156 , 158 can be detected with the help of the deformation sensors.

[0451] Since the deformation concentration regions 152, 154, 156, 158 not only experience expansion and compression due to the deformation regions 82, 84 of the holding arm 30, but also experience expansion and compression due to thermal expansion of the material in the deformation concentration regions 152, 154, 156, 158, reference deformation sensors 182, 184, 186, 188 are assigned to the deformation sensors 172, 174, 176, 178, and the reference deformation sensors are arranged on unloaded reference regions 192, 194, 196, 198 of the deformation transmission element 102, wherein the unloaded reference regions 192, 194, 196, 198 are preferably tongues 202, 204, 206, 208 arranged as close as possible to the deformation concentration regions 152, 154, 156, 158. 8, the tongue, for example, starts from the deformation-free areas 144, 148, extends substantially parallel to the deformation concentration areas 152, 154, 156, 158 but without contact with the deformation concentration areas, and also extends parallel to the deformation-free area 146, wherein the unloaded reference areas 192, 194, 196, 198 preferably have substantially the same material cross-section in the areas where they carry the reference deformation sensors 182, 184, 186, 188, and the substantially same material cross-section has the same material cross-sectional shape as the deformation concentration areas 152, 154, 156, 158, and in addition, the reference deformation sensors 182, 184, 186, 188 are preferably also constructed in the same manner as the deformation sensors 172, 174, 176, 178.

[0452] In order to electronically detect the deformation in the form of extension and compression in the deformation concentration areas 152, 154, 156, 158, the deformation sensors 172, 174, 176, 178 arranged in the deformation concentration areas are arranged in Wheatstone bridges 212, 214, 216, 218, respectively, wherein Figures 16 to 19 As shown, each Wheatstone bridge 212 , 214 , 216 , 218 is located between supply terminals V+ and V−.

[0453] In addition, the deformation sensors 172, 174, 176, 178 located in the Wheatstone bridges 212, 214, 216, 218 are connected in series with reference deformation sensors 182, 184, 186, 188 respectively assigned to the deformation sensors between the supply terminals V+, V−, and in order to construct the Wheatstone bridges 212, 214, 216, 218, resistors 222, 224 are connected in parallel to the series circuit of the deformation sensors 172, 174, 176, 178 and the reference deformation sensors 182, 184, 186, 188, wherein the resistors 222, 224 have the same fixed value.

[0454] Therefore, in each Wheatstone bridge 212, 214, 216, 218, a voltage U can be measured at the intermediate contact lead between the deformation sensors 172, 174, 176, 178 and the reference deformation sensors 182, 184, 186, 188, and at the intermediate contact lead between the resistors 222, 224, respectively, and the voltage U basically corresponds to the deformation, that is, the extension and compression occurring in the deformation concentrated areas 152, 154, 156, 158, wherein the temperature effect is widely compensated and in particular the temperature extension in the deformation concentrated areas 152, 154, 156, 158 is also compensated by arranging the reference deformation sensors 182, 184, 186, 188, which is especially possible when the reference deformation sensors 182, 184, 186, 188 are the same sensors as the deformation sensors 172, 174, 176, 178.

[0455] like Fig. 20 As shown, voltages UD152 , UD154 , UD156 , UD158 measured in Wheatstone bridges 212 , 214 , 216 , 218 and corresponding to the deformations in deformation concentration regions 152 , 154 , 156 , 158 are supplied to an A / D converter 232 of an evaluation unit 230 including an A / D converter.

[0456] The A / D converter 232 determines digitally deformed values ​​D152, D154, D156, D158 from the sensor values ​​UD152, UD154, UD156, UD158, which are forwarded to the load analysis stage 233, which will be described in more detail below.

[0457] The deformation values ​​D153, D154, D156 and D158 are also transmitted, in particular in parallel to the load analysis stage 233, to a force analysis stage 234, which, with the aid of a program code and a processor, based on the digital deformation values ​​D152, D154, D156, D158 and by comparing the deformation values ​​with conversion values, which are conversion values ​​for the deformation values ​​D152, D154, D156, D158 obtained during the calibration process and stored in the memory 236, outputs, for example, a value WF at a corresponding output. x , W.F. z , W.F. y , the output value is assigned to the force F x , F z and F y .

[0458] In the simplest case, a transformation matrix T valid for all spatial directions is stored in the memory 236, by means of which the digital deformation values ​​D152, D154, D156, D158 can be converted into a value WF of the force acting on the connecting element 40. x 、WF z 、WF y .

[0459] If the pair is located according to Fig.21 The value pairs WF in each of the eight zones I to VIII arranged around the towing element 40 x 、WF z 、WF y Calibration can be performed to improve the value WF x 、WF z 、WF y The mass of the connecting element 40 can also be x 、F z 、F y The nonlinear relationship with the digital deformation values ​​D152, D154, D156, D158 is incorporated into the calibration and thus into the conversion, so that the deformation values ​​D152, D154, D156, D158 are converted into the value WF of the force acting on the connecting element 40 x 、WF z 、WF y .

[0460] Thus, the value WF x 、WF z 、WF y The accuracy has been significantly improved.

[0461] Various possibilities are conceivable with regard to the configuration of the evaluation unit 230 , which comprises in particular the A / D converter 232 , the load analysis stage 233 , the force analysis stage 234 and the memory 236 .

[0462] For example, it is conceivable to arrange evaluation unit 230 directly on deformation transmission element 102 .

[0463] It is particularly advantageous if the evaluation unit 230 is arranged on a printed circuit board 240 which is connected to the deformation transmission element 102 but is arranged separately from the deformation transmission element.

[0464] Not only the evaluation unit 230 but also the resistors 222 , 224 of the respective Wheatstone bridges 212 , 214 , 216 , 218 may be arranged on the printed circuit board 240 .

[0465] A particularly advantageous embodiment provides here that the deformation sensors 172, 174, 176, 178 and the reference deformation sensors 182, 184, 186, 188 are arranged on one side of the deformation transfer element 102 and on the side facing the printed circuit board 240, while the evaluation and analysis unit 230, which in particular has the A / D converter 232, the load analysis stage 233, the force analysis stage 234 and the memory 236, is arranged on the printed circuit board 240 and likewise on the side facing the deformation transfer element 102.

[0466] The deformation transmission element 102 and the printed circuit board 240 are preferably also enclosed in a covering material 242 or cast in a covering material 242, so that the deformation transmission element 102, the printed circuit board 240 and the covering material 242 form a common unit 244 ( Fig.23 ).

[0467] For example, Fig. 22 As shown in , the unit 244 can be mounted on the joining elements 114 , 116 , 118 in such a way that the printed circuit board 240 is located on that side of the deformation transmission element 102 which faces away from the holding arm 30 .

[0468] But for example like Fig.24 As shown in FIG. 2 , in the second exemplary embodiment, the unit 244 can also be arranged in such a way that the printed circuit board 240 is located on the side of the deformation transmission element facing the holding arm 30 .

[0469] In the third embodiment, in order to ensure the functions of the reference deformation sensors 182 , 184 , 186 , 188 , for example, a separate temperature sensor 252 , 254 , 256 , 258 is respectively assigned to each of the reference deformation sensors 182 , 184 , 186 , 188 .

[0470] The individual temperature sensors 252, 254, 256, 258 can either be Fig.25 As shown, it is arranged on the circuit board 240, or it can be Fig.26 As shown in the fourth embodiment in FIG. 1 , it is arranged on the deformation transmission element 102 .

[0471] Such additional temperature sensors 252, 254, 256, 258 enable additional temperature measurements to be performed in order to check whether the reference deformation sensors 182, 184, 186, 188 have full functional operating capabilities or to check whether there are erroneous measurements of the voltages UD152, UD154, UD156, UD158 caused by functional limitations or functional interruptions of the reference deformation sensors 182, 184, 186, 188.

[0472] Regardless of whether it is set on the circuit board 240 ( Fig.25 ) or in the case of being arranged on the deformation transfer element 102 ( Fig.26 ), for example, the voltages UD252, UD254, UD256 and UD258 measured on the temperature sensors 252, 254, 256 and 258 are also as Fig. 27 As shown, it is input to the A / D converter 232 and converted into numerical values ​​T252, T254, T256, T258 by the A / D converter, and input to the load analysis level 233 and / or the force analysis level 234, and then checked by the load analysis level 233 and / or the force analysis level 234 before implementing the evaluation and analysis of the corresponding digital deformation values ​​D152, D154, D156, D158.

[0473] In the fifth exemplary embodiment, a holding arm denoted as a whole by 30 ′ is connected to the carrier unit 20 in that a first end 32 ′ of the holding arm 30 ′ is held on the carrier unit 20 , preferably on the transverse carrier 22 , either directly or via a bearing unit 36 ​​′.

[0474] The holding arm 30 ′ comprises a receiving body 31 which is provided with the first end 32 ′ and the second end 34 ′ and is designed to receive a connecting element 40 ′ which is used, for example, for towing a trailer or for fastening a load-carrying unit.

[0475] For example, such a connecting element 40′ is configured as a connecting ball 43′ held on a supporting arm 42′, which allows a very common connection by means of a towing ball joint of a trailer vehicle, wherein the supporting arm 42′ having an insertion section 45 can be inserted and fixed in the insertion receptacle 33′ of the receptacle 31′ through an insertion opening 35 in the receptacle 31 at the rear as viewed in the direction of travel in the working position A.

[0476] The connecting element 40′ is connected to the retaining arm 30′, for example, by means of the supporting arm 42′, so that the connecting ball part 43 extends from the side of the supporting arm 42′ facing away from the roadway 44 in the direction of the central axis 46, which extends approximately vertically when the roadway 44 is horizontal and extends through the ball center point 48 when the connecting ball part 43′ is present.

[0477] In particular, the insertion receptacle 33 ′ is designed such that it receives the insertion section 45 in a form-fitting and detachable manner transversely to the insertion direction E and is secured against displacement in the insertion direction ER by the form-fitting element 41 .

[0478] The insertion section 45 of the support arm 42 ′ is detachably fastened in the receiving body 31 , in particular by means of a fastening pin 41 which extends transversely to the vehicle longitudinal center plane 18 and passes through the receiving body 31 and the support arm 42 ′.

[0479] However, a connecting element 40 ′ configured in this way also allows a simple mounting of the load-bearing unit, since a very common load-bearing unit is also configured to be mounted on the connecting ball 43 and can optionally also be supported additionally on the retaining arm 30 .

[0480] Alternatively, however, only a support arm 42 held on the load-carrying unit can be used as a connecting element 40 ′, which support arm has an insertion section 45 which is suitable for insertion into the insertion receptacle 33 ′.

[0481] To improve the aesthetic effect, the transverse support 22 is preferably arranged below a bumper unit 50 at the rear of the motor vehicle body 12 , wherein the bumper unit 50 covers, for example, the transverse support 22 and a portion of the first end 32 ′ of the retaining arm 30 ′.

[0482] The retaining arm 30' carries the connecting element 40' including the connecting ball 43 via the insertion section 45 which is inserted into the insertion receptacle 33', in particular in the fifth exemplary embodiment shown, wherein the retaining arm 30' in particular as in Figure 28 to Figure 32As in FIG. 1 , the holding arm 30 ′ extends from the pivot bearing unit 35 ′ to which the holding arm 30 ′ is connected at its first end region 32 ′, wherein a pivot bearing body 52 ′ of the pivot bearing unit 36 ​​′ is integrally formed on the first end region 32 ′, for example.

[0483] In the fifth embodiment, the pivot support body 52' of the pivot support unit 36' can be pivotally supported about a pivot axis 54' on a pivot support receiving portion 56', wherein the pivot axis in particular extends transversely to the vertical vehicle longitudinal center plane 18, and the pivot support receiving portion 56' on the one hand guides the pivot support body 52' to rotate about the pivot axis 54' and on the other hand includes a locking portion, which allows the retaining arm 30' to be fixed in a non-rotatable manner relative to the pivot movement about the pivot axis 54' in the working position A and the rest position R.

[0484] With regard to the entirety of the configuration of the pivot bearing unit 36 ​​′ relative to the pivot bearing receptacle 56 ′ and the configuration of the locking portions of the pivot bearing body 52 ′ relative to the pivot bearing receptacle 56 ′, reference is made to DE 10 2016 107 302 A1.

[0485] In order to lock the pivot bearing 52' in the working position A, in particular Fig.31 As shown, a stop element 59' is provided, which passes through the recess of the holding arm 30' and is supported on the end of the insertion section 45 of the support arm 42' inserted into the insertion receptacle 33' facing away from the insertion opening 35', and thereby comes into contact with the stop unit 60' ( Fig.32 ) and simultaneously prevent the pivotal movement of the holding arm 30' having the receiving body 31' around the pivot axis 54', and the stop unit 60' includes a stop unit arranged on the pivot support body 52' and the pivot support receiving portion 56'.

[0486] In addition, if Fig.33 As shown, the locking of the pivot bearing 52 ′ in the rest position R is achieved by a locking device 61 .

[0487] The pivot bearing receptacle 56 ′ is in turn fixedly connected on its side to the transverse carrier 22 via a pivot bearing base 58 ′.

[0488] like Figures 28 to 34 As shown, the retaining arm 30' in the fifth embodiment can be Figure 28 to Figure 32 The working position A shown in FIG. is pivoted into Fig.33 , Fig.34In the static position R shown in the drawing, the connecting element 40' having the connecting ball portion 43 is in the working position so that the connecting element is behind the bumper unit 50 and on the side facing away from the roadway 44. When the connecting element 40' is removed, the insertion opening 35 of the insertion receiving portion 33 is arranged to face the roadway 44 in the static position.

[0489] Here, the retaining arm 30′ in the working position A extends in particular essentially in the vertical vehicle longitudinal center plane 18, wherein, when the connecting element 40′ is constructed as a connecting ball part 43 provided with a supporting arm 42, the connecting element 40′ intersects the vehicle longitudinal center plane 18 in the center, so that in the working position A, the vertical ball part center axis 48 is located in the longitudinal center plane 18.

[0490] In the illustrated embodiment, the receptacle 31′ of the retaining arm 30′ extends from the first end region 32′ with an additional portion 62′ to an intermediate piece 64′, the intermediate piece extends to an intermediate body 66, and an end piece 68 located on the side opposite to the intermediate piece 64 and the additional portion 62 is connected behind the intermediate body 66, and the connecting element 40′ has a supporting arm 42 arranged between the connecting ball portion 43 and the end piece 68 and extends outward above the end piece 68.

[0491] The end piece 68 here forms the end region 34 ′ of the holding arm 30 ′, wherein the holding arm 30 ′ absorbs the forces transmitted to the insertion receptacle 33 ′ by the insertion section 45 of the support arm 42 ′ by means of the insertion receptacle 33 ′.

[0492] like Figures 35 to 40 As shown, the retaining arm 30′ constructed in this way to receive the force transmitted by the insertion section 45 is constructed almost linearly through the additional part 62′, the middle piece 64′ of the intermediate body 66 and the end piece 68, and the retaining arm 30′ is oriented in the working position A so that the force acting on the connecting element 40′, in particular on the ball center point 46, is transmitted to the pivot bearing body 52′ of the pivot bearing unit 36′ through the retaining arm 30′, wherein the pivot axis 54′ represents the center of the force receiving part through the pivot bearing unit 36′, and the load of the connecting element 40′ occurs in the working position A and is to be detected.

[0493] like Figure 28 to Figure 32 As shown, the forces influencing the connecting element 40 are transmitted via the retaining arm 30′ to the bearing unit 36′ and from there to the carrier unit 20, which then directs the forces into the rear region 14 of the motor vehicle body 12, wherein different regions of the retaining arm 30′ are used to detect the forces acting on the connecting element 40.

[0494] In the above-mentioned embodiment, a first deformation region 82 of the holding arm 30' and a second deformation region of the holding arm 30' are used by way of example. The first deformation region 82 is constructed, for example, by a transition region from the intermediate piece 64 to the intermediate body 66', and the second deformation region is constructed by a transition region from the intermediate body 66' to the end piece 68'.

[0495] Furthermore, based on this exemplary embodiment, the intermediate body 66 ′ has a high stability with respect to bending forces in the longitudinal center plane 18 , also transversely thereto, and reacts in particular preferentially to tensile loads.

[0496] For example, the first deformation region 82 , the second deformation region 84 are designed in a targeted manner, for example as regions formed with material weakening or material strengthening, wherein in the simplest case the material weakening can be caused by an introduced cross-sectional deformation.

[0497] Thus, for example, Fig.35 and Fig.36 The force F shown in x So that in the deformation areas 82, 84, on the one hand, tensile forces ZX1, ZX2 ( Fig.36 ), on the other hand, at least when there is a connecting ball 43' on the side facing away from the roadway 44 and arranged at a certain distance relative to the support arm 42' in the operating position, bending forces BX1, BX2 ( Fig.35 ), wherein these forces act in the direction of the longitudinal middle plane 18 of the holding arm 30 ′, in particular in the longitudinal middle plane 18, the force F x It is oriented in the longitudinal center plane 18 perpendicularly to the center axis 46 and facing away from the pivot bearing 52 .

[0498] Furthermore, in the deformation regions 82, 84, as Fig.37 , Fig.38 As shown, when the connecting element 40 is loaded with a force F acting in the direction of the center axis 46 z , bending forces BZ1, BZ2 mainly occur in the deformation regions 82, 84, wherein these forces act in the direction of the longitudinal middle plane 18 of the retaining arm 30, in particular in the longitudinal middle plane 18, and therefore have opposite effects on mutually opposite surfaces with respect to the so-called invariable-length neutral fibers NF.

[0499] In addition, if Fig.39 , Fig.40 As shown, the force F acting on the connecting element 40 and oriented perpendicularly to the longitudinal center plane 18 and the center axis 46 yBending forces BY1 , BY2 are brought about which act in opposite directions on both sides of the longitudinal center plane 18 , but on different sides of the longitudinal center plane.

[0500] In particular, the deformation regions 82 , 84 are designed such that they react to the tensile forces Z and bending forces B with deformations of different magnitudes, for example the deformation region 82 is highly sensitive to the support load and the deformation region 84 is less sensitive to the support load.

[0501] In order to detect these tensile forces ZX1 , ZX2 and bending forces BX1 , BX2 , BZ1 , BZ2 , BY1 , BY2 , a force detection module, designated as a whole by 100 , is provided on the holding arm 30 ′.

[0502] The force detection module 100 includes a deformation transfer element 102, which is rigidly connected to the retaining arm 30' in three fixing areas 104, 106, and 108, wherein the fixing area 104 is located on the side facing the first end 32 and is rigidly connected to an additional part 114 of the retaining arm 30', for example, located on the middle part 64, the fixing area 106 is approximately located in the middle between the fixing areas 104, 108 and is connected to, for example, a retaining additional part 116 located on the middle body 66, in particular in the center of the middle body 66, and the fixing area 108 is connected to an additional part 118 of the retaining arm 30 arranged on the end piece 68, for example, in the central area of ​​the end piece 68 arranged between the middle body 66 and the end 34.

[0503] The connection between the engagement elements 114 , 116 , 118 of the holding arm 30 ′ is hereby rigid and free of play and is preferably realized by welding or gluing, which does not allow for any elasticity of movement between the deformation transmission element 102 and the engagement elements 114 , 116 , 118 .

[0504] The engagement elements 114 , 116 , 118 are preferably likewise rigidly connected to the holding arm 30 ′, in particular integrally formed thereon.

[0505] As described in the first to fourth embodiments, the force detection module 100, the deformation transfer element 102, the joining elements 114, 116, 118, the deformation sensors 172, 174, 176, 178, the reference deformation sensors 182, 184, 186, 188, the Wheatstone bridges 212, 214, 216, 218, the evaluation unit 230, the circuit board 240 with the encapsulation material 242, and the temperature sensors 252, 254, 256, 256 are constructed in the same manner in the fifth embodiment and also operate in the same manner.

[0506] like Fig.41As shown, in order to obtain a measured value vector M for sensor values, which represents the deformation values ​​D152, D154, D156D, D158 corresponding to the measured voltages UD152, UD154, UD156, UD158, and a value WF generated by the evaluation unit 230 or 230′ for the vector K representing the component force, by means of a transformation matrix T x 、WF y 、WF z The correlation between them is corrected or calibrated in all the aforementioned embodiments.

[0507] Since the force vector K has a value of WF x 、WF y 、WF z The three component forces are applied, for example, only to three deformation values ​​from the deformation values ​​of the sensor values ​​UD152, UD154, UD156, UD158, for example to the deformation values ​​D152, D154, D156, in order to construct the measured value vector M.

[0508] like Fig.41 As shown, in order to obtain the respective values ​​WF of the component forces of the force vector K x 、WF z 、WF y , such a measurement value vector M must be multiplied by the transformation matrix T.

[0509] In this case, the transformation matrix T has nine transformation coefficients t 1x , t 2x , t 3x , t 1y , t 2y , t 3y , t 1z , t 2z , t 3z .

[0510] like Fig.42 As shown, in order to determine the conversion coefficient t 1x to 3z The holding arm 40 is fastened in a fixed position on a test stand, for example to the pivot bearing 52 , and the connecting element 40 is influenced with different forces in different spatial directions by means of a force-exerting arm KA.

[0511] For example, by means of the arm KA with a force F in the X direction x and / or force F in the Z direction z and / or force F in the Y direction y Or the influence may be carried out by one or more combinations of these forces.

[0512] As already mentioned, in the simplest case, a transformation matrix T valid for all spatial directions x, v, z is stored in the memory 236, with the aid of which the deformation values ​​D152, D154, D156 can be converted into values ​​WF of the component forces acting on the connecting element 40. x 、WF z 、WF y .

[0513] In such a calibration ( Fig.42 ), three calibration processes are performed in sequence, and for example, in the first calibration process only the force component F x Influencing the connecting element 40, in the third calibration process only with the force component F y Or the force F z The connecting element 40 is influenced and the deformation values ​​D152 , D154 and D156 are subsequently detected in each calibration process.

[0514] Since in each of the three calibration processes, the other force component F y and F z or F x and F z or F x and F y is zero, so after all three calibration processes a system of nine equations is generated, which is used to determine a total of nine unknown conversion coefficients t 1x to 3z .

[0515] But if Fig.43 As shown, it is also possible to work with the deformation values ​​D152, D154, D156, D158 from all four sensor values ​​UD152, UD154, UD156, UD158 in order to determine a total of twelve conversion coefficients t 1x to 4z In this case, a total of four calibration processes are to be performed in order to obtain a total of twelve conversion coefficients t for the twelve unknowns. 1x to 4z The equation of .

[0516] During calibration or correction, the force F z During the adjustment of the holding arm 30 , preferably in the direction of gravity, the adjustment of the holding arm 30 is compared to the motor vehicle 10 being in a substantially horizontal plane.

[0517] During the adjustment of the holding arm 30 in comparison with the motor vehicle 10 which is located on a substantially horizontal surface, the force F xIt also acts in a substantially horizontal direction and in particular in the vertical vehicle longitudinal center plane 18 , and therefore also in the vertical longitudinal center plane 18 of the retaining arm 30 .

[0518] In addition, the force F y acts transversely, in particular perpendicularly, to the vertical longitudinal center plane 18 and perpendicularly to the force F x 、F z effect.

[0519] The applied force F is set here x 、F y 、F z The physical relationship with the correspondingly adjusted deformations represents the simplest possible conception.

[0520] If the pair is located according to Fig.21 and Fig.44 The value pairs WF in each of the eight subareas I to VII arranged in space around the connecting element 40 x 、WF z 、WF y Calibration can be performed to improve the value WF x 、WF z 、WF y The quality of the result is thus also able to reduce the force F acting on the connecting element 40 z 、F z 、F y The nonlinear spatial relationship of the digital deformation values ​​of the voltages UD152, UD154, UD156, UD158 is incorporated into the calibration and thus into the conversion of these deformation values ​​D152, D154, D156, D158 into a value WF of the force acting on the connecting element 40. x 、WF z 、WF y .

[0521] Thus, the value WF x 、WF z 、WF y The accuracy has been significantly improved.

[0522] For the sake of related Fig.44 The octaves I to VIII shown are calibrated. During calibration or correction, in order to determine the special transformation matrix T for the octave, the force F is selected respectively. x 、F y 、F z , so that they are located in a respective octant and in particular all act in the direction of the same point on connecting element 40 .

[0523] To determine the transformation matrix TI for an octant I, for example, only the force components F located in this octant I are used. x I. F z I. F y The power of I.

[0524] The resulting force component values ​​WF for the spaces in each octant I to VIII are: x 、WF z 、WF y It can also be determined more accurately.

[0525] Since when determining the unknown force acting on the connecting element 40, the orientation of the force and therefore also the assignment of the force to an octant are unknown, the force component WF of the force is determined, for example, either by means of a transformation matrix T determined for all spatial directions x 、WF y 、WF z , or the force component WF of this force is obtained by means of one of the transformation matrices TI to TVIII x 、WF y 、WF z , and then by the evaluation unit 230 or 230 ′ and by virtue of the value WF x 、WF y 、WF z It is detected to which of the octants the force is assigned, for example octant III, and then the value WF is determined again with the aid of the transformation matrix determined for this octant, for example with the aid of the transformation matrix TIII. x 、WF y 、WF z .

[0526] like Fig.45 As shown, in order to carry out a load analysis based on the deformation values ​​D152, D154, D156, D158 with the aid of the load analysis stage 233 and / or to determine the load-dependent force F acting on the connecting element 40 x 、F y 、F z , a state evaluation and analysis unit 270 is set, which works together with the evaluation and analysis unit 230 and also has a flow sequence controller 280.

[0527] The flow sequence controller 280 first detects in a state detection stage 282 whether the voltage supply of the evaluation unit 230 is sufficient.

[0528] State detection stage 282 checks the battery voltage of the vehicle, in particular the voltage present at deformation sensors 182 , 184 , 186 , 188 and possibly temperature sensors 252 , 254 , 256 , 258 and evaluation unit 230 , for example, by means of voltage sensor 302 .

[0529] The state detection level 282 also detects, in particular, whether the motor vehicle 10 is in a state that allows detection of the force applied to the retaining arm, which means that it is detected whether the vehicle is in a basically horizontal plane, wherein the standard of a basically horizontal plane is met if the deviation of each plane direction from the absolute horizontal plane is at most ±2°, better ±1°.

[0530] To this end, the state detection stage 282 uses one or more tilt sensors 304 ( Figure 3 , Fig.45 ) to check the orientation of the vehicle having the device according to the present invention relative to a vehicle orientation located in a preset horizontal plane, wherein the tilt sensor 304 can, for example, be arranged in the flow sequence controller 280, or in the motor vehicle 10, or on the carrier unit 20 and be queried by the status detection stage 282.

[0531] If the orientation of the vehicle deviates substantially from the orientation in the predefined horizontal plane, then, for example in the case of large deviations, state detection stage 270 is deactivated.

[0532] Furthermore, in the state detection stage 282 the position of the holding arm 30 is checked to see whether it is in the operating position or outside the operating position.

[0533] For this purpose, the state detection stage 282 uses a sensor group 306 ( Figure 3 , Fig.45 ) Check the working position and / or other positions of the holding arm 30, wherein the working position is checked at least once and when it is found that it is not in the working position, the check is evaluated as negative.

[0534] If, in the state detection stage 282, on the one hand, a sufficient voltage supply is determined, on the other hand, an unnecessary tilt correction or an implementable tilt correction of the motor vehicle 10 is determined, and in addition, it is determined that the retaining arm 30 is in the working position, then the evaluation and analysis unit 230 is activated so as to use the subsequent activation stage 284, so that the evaluation and analysis unit 230 derives the deformation values ​​D152, D154, D156, D158 of the motor vehicle 10 with the retaining arm 30 in the current state.

[0535] During the activation of the evaluation unit 230 , the tilt correction stage 283 is also activated.

[0536] By activating the tilt correction level 283 of the evaluation unit 230, when there are compensable deviations, the deformation values ​​D152, D154, D156, D158 are corrected with the help of stored tilt correction data, for example obtained by calibration, for use in the load analysis level 233 and / or the force analysis level 234.

[0537] After the state detection stage 282 has identified a permissible state for detecting a force acting on the holding arm 30, in particular on the connecting element 40 of the holding arm 30, and after the activation stage 284 has activated the analysis circuit 230, which optionally has the tilt correction stage 283, the no-load detection control stage 286 is preferably used as the next step.

[0538] In the no-load detection control stage 286 , it is first checked whether no-load detection is possible, ie, detection without load on the holding arm 30 , in particular whether load can be detected when no external forces acting on the connecting element 40 of the holding arm 30 are present.

[0539] The no-load detection control level 286, for example, activates the no-load value memory 3121 of the no-load correction level 285, which receives the deformation values ​​D152, D154, D156, D158 converted by the A / D converter 232 when activated and corrected by the tilt correction level 283 when necessary, and saves them as deformation values ​​D0152, D0154, D0156, D0158 obtained without external force, that is, obtained when no-load.

[0540] The value stored in the no-load value memory 3121 of the no-load correction stage 285 is then optionally compared with the no-load reference value D for the state of the holding arm 30, in particular for the state of the connecting element 40, which is present and stored in the no-load reference memory 3122. R 152.D R 154.D R 156.D R 158 in order to carry out a plausibility check to check whether a load on the holding arm 30 caused by external forces, in particular a load on the connecting element 40, can be eliminated.

[0541] The value stored in no-load reference memory 3122 is detected, for example, by previously determining the corresponding deformation value when no-load or by determining the corresponding deformation value when no-load at the factory.

[0542] In addition, the no-load detection control stage 286 detects the time interval between the last time the holding arm 30 moved to the working position and the current time point.

[0543] If, for example, it is determined that the movement of the holding arm 30 into the operating position and the movement of the connecting element 40 into the operating position took place only a few seconds ago, it can be inferred that no external forces are acting on the connecting element 40 yet and that no load can therefore be determined.

[0544] Another possibility is that the empty-car detection control stage 286 activates the camera system 314 ( Figure 1 , Fig.45 ), the camera system 314 is, for example, integrated in a reversing camera system of the motor vehicle 10 or comprised by the reversing camera system and is able to optically detect whether an object is effectively connected to the connecting element 40 and therefore to the retaining arm 30, in particular whether a towing ball joint or a load carrier is effectively connected to the connecting element 40 and therefore to the retaining arm 30.

[0545] Another possibility is that the unloaded detection control stage 286 activates a sensor system 316 ( Figure 2 , Fig.45 ), the ultrasonic sensor is integrated in particular in the rear bumper unit 50 and is also able to detect whether an object affects the retaining arm 30 and the connecting element 40.

[0546] Another possibility for checking whether an object is affecting the connecting element 40 and thus the holding arm 30 is that the unloaded detection control stage 286 detects whether the socket 31 assigned to the device for supplying electrical energy to the trailer vehicle or load-carrying unit is activated, which means that a power supply plug is inserted into the socket ( Figure 2 , Fig.45 ).

[0547] If a power supply plug inserted into the socket 31 is detected by the sensor 318 assigned to the socket 31 , it can be inferred therefrom that an object is placed on the connecting element 40 or on the holding arm 30 , so that no-load detection is not possible.

[0548] Based on one or more of the aforementioned information, the no-load memory 312 of the no-load correction stage 285 is activated so that the deformation values ​​sent from the evaluation and analysis unit 230 can be saved as deformation values ​​D0152, D0154, D0156, D0158 that conform to the state of the retaining arm 30 or the connecting element 40 without external force influence when no-load.

[0549] However, if no state is determined with respect to the no-load detection control level 286, i.e., no-load state detection is possible, then, for example, the deformed values ​​stored in the no-load memory 3122 during the last no-load detection are no longer replaced by the values ​​just stored in the no-load value memory 3121, but they continue to be used and the values ​​stored in the no-load memory 3121 are deleted.

[0550] A no-load correction is subsequently carried out using the deformation values ​​D0152 , D0154 , D0156 and D0158 which are then present in the no-load value memory 3122 of the no-load correction stage 283 .

[0551] After the no-load detection control stage 286 has been fully executed, the load detection control stage 288 is activated.

[0552] The load detection control stage 288 serves to operate the no-load correction stage 285 in such a way that the no-load correction stage 285 detects only the deformation values ​​of the load-dependent force components acting on the connecting element 40 and the holding arm 30 .

[0553] For this purpose, load detection control stage 288 preferably detects whether an onboard function of motor vehicle 10 is activated, ie, for example, whether the operation of all electrical components is activated. This is accomplished, for example, by querying a suitable onboard power supply voltage via sensor 302 .

[0554] Furthermore, the load detection control stage 288 checks, by accessing the sensor 318, whether the socket 31 assigned to the device is activated, the activation of which can be inferred from the presence of an external force ( Fig.45 ), which is caused by the trailer or load-bearing unit.

[0555] Furthermore, the load detection control stage 288 checks by means of the sensor 322 or by querying the vehicle control whether the vehicle is stationary or moving at a speed of less than 5 km / h or faster, so that at a speed of less than 5 km / h it can be assumed that the motor vehicle 10 is basically stationary for the purpose of load detection ( Fig.45 ).

[0556] In addition, the load detection control stage 288 checks, for example, also with the aid of the camera system 314 whether an external object, such as a trailer or a load-bearing unit, is connected to the connecting element 40, and / or the load detection control stage 288 checks with the aid of the camera system 314 and / or the sensor system 315 whether an external object, such as a trailer or a load-bearing unit, is connected to the retaining arm 30 and to the connecting element 40.

[0557] If necessary, load detection control stage 288 additionally checks by means of sensor 306 whether holding arm 30 with connecting element 40 is in an operating position in which a trailer can be towed or a load-carrying unit can be mounted.

[0558] If the load detection control stage 288 detects that an external object acts on the connecting element 40 and the retaining arm 30, the load detection control stage 288 causes the no-load correction stage 285 to take over the deformation values ​​D152, D154, D156, and D158, and causes the no-load memory 3122 to take over the values ​​D0152, D0154, D0156, and D0158, and these values ​​are subtracted from the values ​​D152, D154, D156, and D158 ( Fig.45 ), so that there are deformation values ​​D1521, D1541, D1561, D1581 that appear later, which represent the external force component F that affects the holding unit 30 and the connecting element 40. x 、F z 、F y The value of the deformation determined by the load.

[0559] Based on the load-dependent deformation values ​​D1521, D1541, D1561, D1581 that are then present, the evaluation unit 230 now determines the different load states of the holding arm 30 by means of a load analysis stage 233 with the aid of program code and a processor using one or more analysis methods, and determines the force component F by means of the aforementioned transformation. x 、F y and F z Not required.

[0560] Possible load states involve, for example, identifying whether Fig.47 The bicycle carrier 350 is shown connected to the connecting element 40 of the holding arm 30, or whether Fig.46 A trailer 360 is shown connected to the connecting element 40 .

[0561] The analytical method used for this is based, for example, on the fact that the bicycle carrier 350 acts on the retaining arm 30 and in particular on the deformation regions 82 and 84 in such a way that both the deformation region 82 and the deformation region 84 are subject to significant bending forces BX and BZ, which are generated by the bicycle carrier 350 , while the pure tensile force ZX has a small contribution, so that both deformation regions react with similar deformations.

[0562] However, if a trailer vehicle 360 ​​is connected to the connecting element 40, the trailer vehicle 360 ​​is on the connecting element 40 with a supporting load on the one hand, which causes a force FZ, and on the other hand, the trailer vehicle acts on the connecting element 40 with a force FX, which depends on the mass of the vehicle when the vehicle is accelerating, rather than the mass of the vehicle when the vehicle is stationary or traveling at a negligible speed.

[0563] Therefore, if the analysis method implemented by the load analysis stage 233 is implemented when the vehicle is stationary or at a negligible speed of the vehicle (less than 5 km / h), the tension ZX on the load areas 82 and 84 is small and can even be ignored, unless the vehicle is stationary on an inclined surface, in which case the tension can be at least partially compensated by the inclination correction stage 283.

[0564] Fig.48 and Fig.49 The example shows the deformation values ​​D152 / 1, D154 / 1 of the deformation region 82 which is highly sensitive to the supporting load and the deformation values ​​D156 / 1, D158 / 1 of the deformation region 84 which is less sensitive to the supporting load, measured when there is a trailer 350 and a bicycle carrier 360, wherein the low load marked MIN in the figure and the maximum load marked MAX in the figure of the retaining arm 30 are respectively shown.

[0565] For example, Fig.46 In the trailer 350 shown, the extension values ​​D1561 and D1581 of the deformation region 84 that is less sensitive to the support load are close to zero, while at the minimum load, the deformation values ​​D1521 and D1541 of the deformation region 82 that is highly sensitive to the support load are approximately the same and have values ​​greater than the deformation values ​​D1561 and D1581. Fig.48 )

[0566] When the maximum load is present with the aid of the trailer 350, the deformation values ​​D1561 and D1581 of the deformation region 84 which is less sensitive to the supporting load are still close to zero, while the deformation values ​​D1521 and D1541 of the deformation region 82 which is highly sensitive to the supporting load are greater than the values ​​at the minimum supporting load.

[0567] This is because the bending moment BZ caused by the supporting load FZ causes a very small deformation in the deformation area 84, which can be ignored in certain circumstances, while in the deformation area 82 far away from the connecting element 40, the deformations D1521 and D1541 caused by the bending moment BZ are always larger, and therefore are larger at the maximum supporting load FZ than at the minimum supporting load FZ.

[0568] In contrast, there are Fig.47When the bicycle carrier 360 is shown, the deformation values ​​show different performances ( Fig.49 ).

[0569] For example, the deformation values ​​D1561 and D1581 are significantly different from zero, and at the minimum load, although the values ​​are smaller than the deformation values ​​D1521 and D1541, the magnitudes are qualitatively similar.

[0570] This is because the bicycle carrier 360 generates significant bending forces BX and BZ which significantly influence both the deformation region 82 and the deformation region 84, wherein Fig.49 As shown, the influence on the deformation region 84 is smaller than the influence on the deformation region 82 .

[0571] However, if the bicycle carrier 360 reaches the maximum load of the connecting element 40, then Fig.49 As shown, the deformation values ​​D1561 and D1581 are even larger, and in certain cases are more different than at low loads, and the deformation values ​​D1561 and D1581 are close to the maximum allowable deformation values.

[0572] When a maximum load is present through the bicycle carrier 360, the different parts between the deformation values ​​D1561 and D1581 as well as D1521 and D1541 measured on different sides of the longitudinal center plane are caused, for example, on the one hand by a force FY caused by uneven loading of the bicycle carrier on different sides of the connecting element 40 or by an asymmetry of the retaining arm 30, which is caused, for example, by the fact that the retaining arm 30 is pivotably supported with a pivot axis 54 extending obliquely to the longitudinal center plane 18.

[0573] The load analysis stage 233 can now differentiate between a trailer 350 connected to the connecting element 40 or a bicycle carrier 360 connected to the connecting element 40 using different analysis methods.

[0574] Each of the analysis methods described below first checks whether the deformation values ​​D1521, D1541, D1561 and D1581 are within the permissible value range between the values ​​D0 and Dmax. If this is the case, a further analysis is started.

[0575] The first and simplest analysis method stipulates that the deformation values ​​are checked according to the first analysis standard, that is, whether the deformation values ​​D1561 and D1581 of the deformation area 84 which is less sensitive to the supporting load are close to D0 relative to the deformation values ​​D1521 and D1541 of the deformation area 82 which is highly sensitive to the supporting load.

[0576] According to a first analysis criterion, in particular the deformation values ​​D1561 and D1581 are compared with a preset first reference value range RB0 containing the value D0, for example, the reference value range comprises the value D0 plus / minus 5% of Dmax.

[0577] If deformation values ​​D1561 and D1581 are within first reference value range RB0 , a first criterion is given that trailer vehicle 350 is present on connecting element 40 .

[0578] Thus, a result is already provided using the first evaluation criterion for distinguishing between a trailer vehicle 350 connected to the connecting element 40 or a bicycle carrier 360 connected to the connecting element 40 .

[0579] Furthermore, when the second analysis method is used, the second analysis criterion is that all deformation values ​​D1561, D1581, D1521 and D1541 are significantly different from D0 when the bicycle carrier 360 is present.

[0580] The second analysis criterion, for example, stipulates a threshold value S of the deformation values ​​D156l, D158l, D152l and D154l as a second reference value, which threshold value is, for example, 5% or 10% of Dmax. If all deformation values ​​D156l, D158l, D152l and D154l are higher than the threshold value S, then the second analysis criterion starts from the bicycle carrier 360 connected to the retaining element 40.

[0581] The second evaluation criterion, in particular in combination with the first evaluation criterion, makes it possible to differentiate between a trailer vehicle 350 connected to the connecting element 40 and a bicycle carrier 360 connected to the connecting element 40 .

[0582] The third analysis standard used in the third analysis method stipulates that the difference DI between the deformation value D1521 of the deformation area 82 which is highly sensitive to the supporting load and the deformation value D1561 of the deformation area which is low sensitive to the supporting load with respect to its position relative to the longitudinal mid-plane is obtained, or the difference DI between the deformation value D1541 of the deformation area 82 which is highly sensitive to the supporting load and the deformation value D1581 of the deformation area 84 which is low sensitive to the supporting load with respect to its position relative to the longitudinal mid-plane is obtained, and the difference DI is established in association with the respective absolute values ​​of the deformation values ​​D1521 or D1541 or D1561 or D1581.

[0583] ( Fig.48 , Fig.49 )

[0584] like Fig.48As can be clearly seen, when the trailer 350 is present, the aforementioned difference is approximately equal to the absolute value of the deformation value D1521 or D1541 of the deformation region 82 which is highly sensitive to the supporting load, and Fig.49 As shown, when the bicycle carrier 360 is present, the aforementioned difference is only a small portion of the aforementioned deformation values ​​D1521 and D1541.

[0585] The third analysis standard, for example, stipulates a trailer reference value band RAWB as a preset reference value, and the trailer reference value band is between the maximum value of the deformation values ​​D152l and D154l of the deformation area 82 which is highly sensitive to the supporting load and 50% of the maximum value of the deformation values ​​D152l and D154l of the deformation area 82 which is highly sensitive to the supporting load, and the third analysis standard stipulates a bicycle carrier reference value band RFWB as a preset reference value, and the bicycle carrier reference value band is between 50% of the maximum value of the deformation values ​​D152l and D154l of the deformation area 82 which is highly sensitive to the supporting load and D0, and depending on whether the difference DI is in the trailer reference value band RAWB or the bicycle carrier reference value band RFWB, the trailer 350 and the bicycle carrier 360 can be distinguished.

[0586] The third evaluation criterion can therefore also differentiate between a trailer vehicle 350 connected to the connecting element 40 or a bicycle carrier connected to the connecting element 40 .

[0587] The load analysis stage 233 can therefore forward either a signal of the trailer 350 connected to the connecting element 40 , such as the signal A, or a signal of the bicycle carrier 360 connected to the connecting element 40 , such as the signal F, to the communication stage 290 of the state evaluation unit 270 .

[0588] Furthermore, the communication stage 290 is able to communicate with the vehicle, in particular the onboard electronics, and to forward the signals, for example, to a speed monitoring unit 322 or a stabilization system 326 of the vehicle or a chassis control unit 328 of the motor vehicle in order to adjust the speed, chassis stabilization and chassis settings depending on the operation with a trailer 350 or with a bicycle carrier 360.

[0589] Furthermore, communication level 290 may also cooperate with display level 292 which displays to the driver on display device 294 , for example, the fact that an operation with trailer 350 or with bicycle carrier 360 is taking place.

[0590] The operating method of the load analysis stage 233 can be further simplified.

[0591] Another simplified operating method provides that only one deformation value is used for analyzing the standard deformation value from the deformation values ​​D1521 and D1541 as well as D1561 and D1581, for example, the deformation value D1521 and the deformation value D1561 or D1541 and D1581, i.e., the deformation values ​​detected by means of the sensors 152 and 156 or 154 and 158 located on the same side of the longitudinal midplane 18.

[0592] When applying the aforementioned three analysis criteria, the deformation values ​​D1521 and D1561 or D1541 and D1581 can also identify the different behaviors of the deformation regions 82 and 84 when there is a trailer 350 or a bicycle carrier 360, and can therefore be used to identify a trailer or a bicycle carrier.

[0593] The load analysis stage 233 can also be operated in a simplified operating mode.

[0594] like Fig.50 and 51 As shown, a simplified operating mode stipulates that a deformation intermediate value D821 and D841 are respectively constructed from the deformation values ​​D1521 and D1541 of the deformation area 82 which is highly sensitive to the support load and the deformation values ​​D1561 and D1581 of the deformation area 84 which is less sensitive to the support load, and the deformation intermediate values ​​are evaluated and analyzed with the aid of an analytical method.

[0595] The first analysis criterion and the second and third analysis criteria can all be applied in a similar manner to the deformation intermediate values ​​D821 and D841, because the different performances of the deformation areas 82 and 84 are also reflected in the deformation intermediate value D82 formed by D1521 and D1541 and in the deformation intermediate value D84 formed by D1561 and D1581, that is, when a trailer is present, the deformation intermediate value D84 is near D0 and mainly only the deformation intermediate value D82 and DO are significantly different, while when a bicycle carrier 360 is present, the deformation intermediate values ​​D82 and D84 are both significantly different from D0.

[0596] Unless it is specified that three components F x 、F y and F z Otherwise, the force detection module 100 according to the present invention may also have only two deformation concentration areas, that is, the deformation in the deformation area 82 that is highly sensitive to the supporting load is transmitted to one deformation concentration area, and the deformation in the deformation area 84 that is less sensitive to the supporting load is transmitted to one deformation concentration area, and then the deformation is detected by the deformation sensor assigned to the deformation concentration area.

[0597] In such a simplified embodiment, the deformation concentration regions are preferably located in the vicinity of the longitudinal mid-plane 18 of the holding arm 30 or in the longitudinal mid-plane of the holding arm 30 .

[0598] The load detection control stage 288 can also simultaneously activate the force analysis stage 234 in the analysis circuit 230 or 230', which then determines the values ​​WFx1, WFz1 and WFy1 and thus determines the load-dependent forces on the holding arm 30 and the connecting element 40, which represent the external force component F acting on the holding arm 30 and the connecting element 40. x , F z and F y .

[0599] The force component F x , F z and F y The same may be transmitted to the communication stage 290 , which also transmits these force components to the speed control 322 as well as to the stabilization system 326 and the chassis control 328 .

[0600] Likewise, for example, communication stage 290 forwards the numerical value to presentation stage 292 , which then displays the numerical value, for example, on a display device.

[0601] Another possible load state is realized by using the fourth analysis method, that is, when the force F x , F y or F z A rough estimate of the total load size can be made in this case.

[0602] When the trailer 350 is identified by one or more of the first to third analysis criteria, the fourth analysis method determines the size of one or two of the deformation values ​​D1521 and D1541 that are highly sensitive to the supporting load or the deformation intermediate value D82 of the deformation area 82 that is sensitive to the supporting load, or determines the size of one or two of the deformation values ​​D1541 and D1561 that are less sensitive to the supporting load or the deformation intermediate value D84 of the deformation area 84 that is less sensitive to the supporting load, so as to identify how much force is applied to the connecting element 40 when there is a bicycle carrier.

[0603] like Figures 48 to 51As shown, the load of the connecting element is obtained with the help of load reference values ​​B1 to B6, by determining between which load reference values ​​of the load reference values ​​B1, B2, B3, B4, B5, B6 the individual deformation values ​​D1521, D1541, D1561 and D1581 or the deformation intermediate value D82 or D84 are located, so that, for example, through the five load segments BS1 to BS5 it is known that the deformation value or the deformation intermediate value can be classified into which load segment, and as load segments BS1 to BS5 can be forwarded from the load analysis level 233 via the communication level 290 in the aforementioned manner.

[0604] For example, the magnitude of the total force acting on the connecting element 40 can be determined at least qualitatively based on one or more predefined load reference values ​​B1 . . . B6 , without the magnitude of the force having to be absolutely determined.

[0605] In addition, the fifth analysis method can be used by means of the fifth analysis standard by only and Figures 48 to 51 The comparison of the maximum load reference value B6 in the communication stage 290 determines to what extent an overload has occurred, i.e. to what extent the load reference value B6 has been exceeded, or determines to what extent an overload will occur, i.e. to what extent the load reference value B6 will be directly reached. The information is also conveyed via the communication stage 290 as a warning signal WB.

[0606] Other possible load states relate to the behavior of trailer vehicle 350 , in particular its dynamic behavior during travel.

[0607] The premise for determining the load state is that it is determined according to one or more of the first to third analysis methods that the trailer vehicle 350 is connected to the connecting element 40 .

[0608] In the sixth analysis method, a time-resolved detection of each of the deformation values ​​D1521 , D1541 , D1561 and D1581 is performed during vehicle travel with the aid of a sixth analysis criterion in order to identify sudden changes in the deformation values.

[0609] For example Fig.52 As shown, when there is a trailer 350 that is identified as a trailer by the first three analysis criteria, this is the case if all deformation values ​​show a short-term change in deformation values ​​D1521, D1541, D1561 and D1581, and all deformation values ​​D show an increase or decrease in value.

[0610] In this case, an additional evaluation analysis of the slope F5 of the short-term changing edge F and / or an additional evaluation analysis of the duration Z of the increase of each deformation value D from the previous starting value to the maximum value is performed, and it is possible to draw inferences from the evaluation analysis about the operating mode of the braking of the trailer 350 or other problem-dependent behaviors of the trailer 350, which lead to a sudden change of the deformation value D of the two deformation areas 82 and 84 to a maximum value, and the behavior occurs, for example, in a time interval Z that is smaller than the reference time interval ZR, for example less than 0.5 seconds of the reference time interval ZR.

[0611] If, for example, the inertia brake of the trailer 350 operates normally, a small edge slope FS or a large duration Z is detected, or if the inertia brake does not operate normally, a duration Z exceeding a preset reference value for the edge slope FS and / or being less than a stored reference duration RZ is detected, and a warning signal WA is then generated, which is conveyed by the communication unit 290.

[0612] The seventh and eighth analysis methods described below will introduce other analysis methods for evaluating and analyzing the dynamic performance of the trailer 350 .

[0613] like Fig.53 As shown, in the seventh and eighth analysis methods, after identifying the trailer 350 connected to the connecting element 40 during vehicle travel, the deformation values ​​are detected in a time-resolved manner, corresponding to anti-phase oscillations, relative to the intermediate values ​​M152, M154, M156 and M158, respectively, wherein the deformation values ​​are the deformation values ​​D1521, D1541 of the deformation section 82 detected on the opposite sides of the longitudinal center plane 18 and the deformation values ​​D1561, D1581 of the deformation section 84 detected on the opposite sides of the longitudinal center plane 18, so as to identify lateral forces on the connecting element 40 that are transverse to the driving direction and are, for example, attributed to the rolling motion of the trailer 350, wherein the amplitude AS of the oscillation indicates the degree of strong rolling motion and / or the period duration PS of the oscillation generated by the rolling motion is preferably in a range of greater than one second.

[0614] The amplitude AS of the oscillation is compared with a preset reference value RAS according to the seventh analysis criterion, and the period duration PS of the oscillation is compared with a preset reference value RPS according to the eighth analysis criterion to identify whether the trailer 350 involves a left-right shaking movement that endangers the tractor, and then a warning signal WS is output, which is conveyed by the communication unit 290.

Claims

1. A method for operating a device for connecting a trailer and / or a load-bearing unit (360) which can be assembled at the rear of a motor vehicle body, the device comprising a holding arm (30) which is fixedly connected to the motor vehicle body (12) at a first end (32) during operation and carries a connecting element (40) for the trailer (350) and / or the load-bearing unit (360) at a second end, wherein: A force applied to the connecting element (40) during operation and transmitted by the holding arm (30) to the motor vehicle body (12) is detected by means of deformation sensors (172, 174, 176, 178) by means of an evaluation unit (230), wherein the holding arm (30) has at least two deformation regions (82, 84), and when a force acts on the holding arm (30), the deformation behavior of the deformation region is detected by at least one deformation sensor (172, 174, 176, 178), wherein the deformation sensor The device is rigidly connected to the corresponding deformation areas (82, 84) of the retaining arm (30), so as to detect the deformation performance of the deformation areas, and is characterized in that the evaluation and analysis unit (230) has a load analysis stage (233), which uses an analysis method to obtain at least one load type of the retaining arm (30) based on the deformation values ​​(D152, D154, D156, D2158) of the at least two deformation areas (82, 84) obtained from the deformation sensors (172, 174, 176, 178).

2. The method according to claim 1, characterized in that The load analysis stage (233) uses the deformation values ​​(D152, D154, D156, D158) without converting them to vertical directions (F z ) and / or forces in the longitudinal direction of the vehicle (24) and / or forces transverse to the longitudinal midplane of the vehicle (F y )’s force.

3. The method according to any one of the preceding claims, characterized in that At least one analysis method is a numerical comparison method.

4. The method according to any one of the preceding claims, characterized in that The numerical comparison method compares the deformation values ​​(D) with each other and / or compares the deformation values ​​with reference values ​​(RB0, S, RAWB, RFWB, B1...B6, RFS, ZR, RAS, RPS).

5. The method according to claim 4, characterized in that The reference values ​​are predefined, in particular stored reference values ​​(RB0, S, RAWB, RFWB, B1 . . . B6, RFS, ZR, RAS, RPS).

6. The method according to claim 4 or 5, characterized in that: The reference values ​​(RB0, S, RAWB, RFWB, B1...B6, RFS, ZR, RAS, RPS) are obtained through experiments.

7. The method according to claim 6, characterized in that The reference values ​​are obtained through load testing of representative holding arms (30).

8. The method according to any one of the preceding claims, characterized in that At least one analysis method evaluates the absolute value of the load-dependent deformation value (D).

9. The method according to claim 8, characterized in that The analysis criterion is based on a comparison of the absolute value of the load-dependent deformation value (D) with a threshold value (S) as a reference value.

10. The method according to claim 8 or 9, characterized in that: At least one analysis criterion is based on a comparison of each of the absolute values ​​of the load-dependent deformation values ​​(D) with a stored reference value range (RB0).

11. The method according to any one of the preceding claims, characterized in that At least one analysis method compares at least one deformation value (D) of a deformation region (82) with at least one deformation value (D) of at least one other deformation region (84).

12. The method according to any one of the preceding claims, characterized in that The analysis method is based on the comparison of the behavior of the deformation values ​​(D152, D154) of the deformation areas with high sensitivity to the support load relative to the deformation areas with low sensitivity to the support load.

13. The method according to claim 11 or 12, characterized in that: The analytical method results in the difference of two deformation values ​​(D).

14. The method according to claim 13, characterized in that The analytical method yields the ratio of the difference between the two deformation values ​​(D) relative to the maximum of the two deformation values ​​(D).

15. The method according to any one of claims 11 to 14, characterized in that The analysis criterion is based on a comparison of the behavior of at least one deformation value (D152, D154) of a deformation region (82) that is highly sensitive to support loads relative to at least one deformation value (D154, D156) of a deformation region (84) that is less sensitive to support loads.

16. The method according to claim 15, characterized in that The analysis criterion is based on the ratio of the difference of the deformation values ​​(D) to the maximum of the two deformation values ​​(D) compared to a stored reference value range (RAWB, RFWB).

17. A method according to any one of the preceding claims, characterised in that By comparing the deformation value (D152, D154, D156, D158) determined by the load with at least one load reference value (B1...B6) preset for the deformation value, an analytical method is used to determine the size of the deformation value (D152, D154, D156, D158) determined by the load when at least one deformation area (82, 84) exists.

18. The method according to claim 17, characterized in that By assigning at least one load-dependent deformation value (D152, D154, D156, D158) to a range (BS1, BS2, BS3, BS4, BS5) between two consecutive load reference values ​​(B1...B6), the analysis method assigns at least one load-dependent deformation value (D152, D154, D156, D158) to multiple preset load reference values ​​(B1...B6).

19. The method according to claim 17 or 18, characterized in that The evaluation criterion is based on the assignment of at least one of the deformation values ​​to a series of at least three load reference values ​​( B1 to B6 ) provided for this deformation value.

20. The method according to any one of the preceding claims, characterized in that The analysis method carries out a comparison of at least one of the deformation values ​​(D152, D154, D156, D158) with an assigned maximum load reference value (B6).

21. The method according to claim 20, characterized in that The evaluation criterion is based on an assignment of at least one of the load-dependent deformation values ​​(D152, D154, D156, D158) to a maximum load reference value (B6) assigned to the deformation value.

22. The method according to any one of the preceding claims, characterized in that The analysis method detects at least one of the load-dependent deformation values ​​(D152, D154, D156, D158) in a time-resolved manner.

23. The method according to claim 22, characterized in that The analysis criterion is based on a short-term temporal change in at least one of the deformation values ​​( D152 , D154 , D156 , D158 ).

24. The method according to claim 23, characterized in that The analysis method detects a slope characteristic from at least one of the load-dependent deformation values ​​(D152, D154, D156, D158).

25. The method according to claim 24, characterized in that The analysis criterion compares the edge slope (FS) of the slope characteristic with a stored reference value (RFS).

26. The method according to any one of claims 22 to 25, characterized in that The analysis method determines the time period (Z) for at least one of the load-dependent deformation values ​​(D) to increase to a maximum value.

27. The method according to any one of claims 22 to 26, characterized in that The analysis criteria are based on comparing the duration (Z) to a reference time (RZ).

28. The method according to any one of claims 22 to 27, characterized in that The evaluation criterion is based on a time curve of at least one of the deformation values.

29. The method according to any one of claims 22 to 28, characterized in that The analysis method detects the time curve of the oscillation of at least one of the deformation values ​​(D152, D154, D156, D158) about a middle value of the oscillating deformation value (D152, D154, D156, D158).

30. The method according to claim 29, characterized in that The analysis criterion is based on a comparison of the amplitude (AS) of the oscillation of one of the load-dependent deformation values ​​(D152, D154, D156, D158) about a median value with a reference value (RAS).

31. The method according to claims 28 to 30, characterized in that The evaluation criterion is based on a comparison of a cycle duration (PS) of one of the load-dependent deformation values ​​with a reference cycle duration (RPS).

32. A method according to the preamble of claim 1 or according to any one of the preceding claims, characterized in that Each deformation value (D) applied by the load analysis stage (233) is corrected by the no-load correction stage (285).

33. The method according to claim 32, characterized in that The no-load correction stage (285) produces a no-load deformation value (D1) and subtracts it from the deformation value (D) produced under load.

34. The method according to claim 32 or 33, characterized in that The no-load correction stage (285) is activated before the holding arm (30) is loaded.

35. The method according to any one of claims 32 to 34, characterized in that The no-load correction stage (285) is activated after the holding arm (30) has been moved into the working position.

36. A method according to any one of the preceding claims, characterised in that Each deformation value (D) applied by the load analysis stage (233) is corrected by a tilt correction stage (283) which correlates the deformation value (D) to the orientation of the retaining arm (30) when the vehicle is stationary on a horizontal reference surface, correcting the actual orientation of the retaining arm (30) due to the tilt of the vehicle.

37. The method according to claim 36, characterized in that The tilt correction stage (283) changes the deformation value (D) of the deformation region (152, 154, 156, 158) in such a way that the influence of the changed orientation of the retaining arm (30) relative to the orientation of the vehicle at rest on a horizontal reference surface is taken into account in the deformation region.

38. The method according to claim 36 or 37, characterized in that The tilt correction stage (283) operates with the stored tilt correction value.

39. The method according to claim 38, characterized in that The tilt correction stage (283) operates with experimentally determined tilt correction values.

40. A device for connecting a trailer and / or a load-bearing unit (360) which can be assembled on the rear of a motor vehicle body, the device comprising a retaining arm (30) which is fixedly connected to the motor vehicle body (12) at a first end (32) during operation and carries a connecting element (40) for the trailer (350) and / or the load-bearing unit (360) at a second end, wherein: A force applied to the connecting element (40) during operation and transmitted by the holding arm (30) to the motor vehicle body (12) is detected by an evaluation unit (230) with the aid of deformation sensors (172, 174, 176, 178), wherein the holding arm (30) has at least two deformation regions (82, 84), and when a force acts on the holding arm (30), the deformation behavior of the deformation region is detected by at least one deformation sensor (172, 174, 176, 178), wherein the deformation sensor The sensor and the corresponding deformation area (82, 84) of the retaining arm (30) are rigidly connected to each other, so as to detect the deformation performance of the deformation area, and is characterized in that the evaluation and analysis unit (230) has a load analysis stage (233), which uses an analysis method to obtain at least one load type of the retaining arm (30) based on the deformation values ​​(D152, D154, D156, D2158) of the at least two deformation areas (82, 84) obtained from the deformation sensors (172, 174, 176, 178).

41. The device according to claim 40, characterized in that The load analysis stage (233) uses the deformation values ​​(D152, D154, D156, D158) without converting them to vertical directions (F z ) and / or forces in the longitudinal direction of the vehicle (24) and / or forces transverse to the longitudinal midplane of the vehicle (F y )’s force.

42. The device according to any one of claims 40 to 41, characterized in that At least one analysis method is a numerical comparison method.

43. The device according to any one of claims 40 to 42, characterized in that The numerical comparison method compares the deformation values ​​(D) with each other and / or compares the deformation values ​​with reference values ​​(RB0, S, RAWB, RFWB, B1...B6, RFS, ZR, RAS, RPS).

44. The device according to claim 43, characterized in that The reference values ​​are predefined, in particular stored reference values ​​(RB0, S, RAWB, RFWB, B1 . . . B6, RFS, ZR, RAS, RPS).

45. The device according to claim 43 or 44, characterized in that The reference values ​​(RB0, S, RAWB, RFWB, B1...B6, RFS, ZR, RAS, RPS) are obtained through experiments.

46. ​​The device according to claim 45, characterized in that The reference values ​​are obtained through load testing of representative holding arms (30).

47. The device according to any one of claims 40 to 46, characterized in that At least one analysis method evaluates the absolute value of the load-dependent deformation value (D).

48. The device according to claim 47, characterized in that The analysis criterion is based on a comparison of the absolute value of the load-dependent deformation value (D) with a threshold value (S) as a reference value.

49. The device according to claim 47 or 48, characterized in that At least one analysis criterion is based on a comparison of each of the absolute values ​​of the load-dependent deformation values ​​(D) with a stored reference value range (RB0).

50. The device according to any one of claims 40 to 49, characterized in that At least one analysis method compares at least one deformation value (D) of a deformation region (82) with at least one deformation value (D) of at least one other deformation region (84).

51. The device according to any one of claims 40 to 50, characterized in that The analysis method is based on the comparison of the behavior of the deformation values ​​(D152, D154) of the deformation areas with high sensitivity to the support load relative to the deformation areas with low sensitivity to the support load.

52. The device according to claim 50 or 51, characterized in that The analytical method results in the difference of two deformation values ​​(D).

53. The device according to claim 52, characterized in that The analytical method yields the ratio of the difference between the two deformation values ​​(D) relative to the maximum of the two deformation values ​​(D).

54. The device according to any one of claims 50 to 53, characterized in that The analysis criterion is based on a comparison of the behavior of at least one deformation value (D152, D154) of a deformation region (82) that is highly sensitive to support loads relative to at least one deformation value (D154, D156) of a deformation region (84) that is less sensitive to support loads.

55. The device according to claim 54, characterized in that The analysis criterion is based on the ratio of the difference of the deformation value (D) to the maximum of two deformation values ​​(D) compared to a stored reference value range (RAWB, RFWB).

56. The device according to any one of claims 40 to 55, characterized in that By comparing the deformation value (D152, D154, D156, D158) determined by the load with at least one load reference value (B1...B6) preset for the deformation value, an analytical method is used to determine the size of the deformation value (D152, D154, D156, D158) determined by the load when at least one deformation area (82, 84) exists.

57. The device according to claim 56, characterized in that By assigning at least one load-dependent deformation value (D152, D154, D156, D158) to a range (BS1, BS2, BS3, BS4, BS5) between two consecutive load reference values ​​(B1...B6), the analysis method assigns at least one load-dependent deformation value (D152, D154, D156, D158) to multiple preset load reference values ​​(B1...B6).

58. The device according to claim 56 or 57, characterized in that The evaluation criterion is based on the assignment of at least one of the deformation values ​​to a series of at least three load reference values ​​( B1 to B6 ) provided for this deformation value.

59. The device according to any one of claims 40 to 58, characterized in that The analysis method carries out a comparison of at least one of the deformation values ​​(D152, D154, D156, D158) with an assigned maximum load reference value (B6).

60. The device according to claim 59, characterized in that The evaluation criterion is based on an assignment of at least one of the load-dependent deformation values ​​(D152, D154, D156, D158) to a maximum load reference value (B6) assigned to the deformation value.

61. The device according to any one of claims 40 to 60, characterized in that The analysis method detects at least one of the load-dependent deformation values ​​(D152, D154, D156, D158) in a time-resolved manner.

62. The device according to claim 61, characterized in that The analysis criterion is based on a short-term temporal change in at least one of the deformation values ​​( D152 , D154 , D156 , D158 ).

63. The device according to claim 62, characterized in that The analysis method detects a slope characteristic from at least one of the load-dependent deformation values ​​(D152, D154, D156, D158).

64. The device according to claim 63, characterized in that The analysis criterion compares the edge slope (FS) of the slope characteristic with a stored reference value (RFS).

65. The device according to any one of claims 61 to 64, characterized in that The analysis method determines the time period (Z) for at least one of the load-dependent deformation values ​​(D) to increase to a maximum value.

66. The device according to any one of claims 61 to 65, characterized in that The analysis criteria are based on comparing the duration (Z) to a reference time (RZ).

67. The device according to any one of claims 61 to 66, characterized in that The evaluation criterion is based on a time curve of at least one of the deformation values.

68. The device according to any one of claims 61 to 67, characterized in that The analysis method detects the time curve of the oscillation of at least one of the deformation values ​​(D152, D154, D156, D158) about a middle value of the oscillating deformation value (D152, D154, D156, D158).

69. The device according to claim 68, characterized in that The analysis criterion is based on a comparison of the amplitude (AS) of the oscillation of one of the load-dependent deformation values ​​(D152, D154, D156, D158) about a median value with a reference value (RAS).

70. The device according to claims 67 to 69, characterized in that The evaluation criterion is based on a comparison of a cycle duration (PS) of one of the load-dependent deformation values ​​with a reference cycle duration (RPS).

71. The device according to the preamble of claim 40 or any one of claims 40 to 68, characterized in that Each deformation value (D) applied by the load analysis stage (233) is corrected by the no-load correction stage (285).

72. The device according to claim 71, characterized in that The no-load correction stage (285) produces a no-load deformation value (D1) and subtracts it from the deformation value (D) produced under load.

73. The device according to claim 71 or 72, characterized in that The no-load correction stage (285) is activated before the holding arm (30) is loaded.

74. The device according to any one of claims 71 to 73, characterized in that The no-load correction stage (285) is activated after the holding arm (30) has been moved into the working position.

75. The device according to any one of claims 40 to 74, characterized in that Each deformation value (D) applied by the load analysis stage (233) is corrected by a tilt correction stage (283) which correlates the deformation value (D) to the orientation of the retaining arm (30) when the vehicle is stationary on a horizontal reference surface, correcting the actual orientation of the retaining arm (30) due to the tilt of the vehicle.

76. The device according to claim 75, characterized in that The tilt correction stage (283) changes the deformation value (D) of the deformation region (152, 154, 156, 158) in such a way that the influence of the changed orientation of the retaining arm (30) relative to the orientation of the vehicle at rest on a horizontal reference surface is taken into account in the deformation region.

77. The device according to claim 75 or 76, characterized in that The tilt correction stage (283) operates with the stored tilt correction value.

78. The device according to claim 77, characterized in that The tilt correction stage (283) operates with experimentally determined tilt correction values.

79. The device according to the preamble of claim 40 or any one of claims 40 to 78, characterized in that At least two deformation sensors (172, 174, 176, 178) of the sensor assembly (170) are arranged on the same side of a neutral fiber of the retaining arm (30), and the length of the neutral fiber does not change when the retaining arm (30) is bent and deformed.

80. The device according to claim 79, characterized in that A force detection module (100) is arranged on one side of the holding arm (30, 30'), which comprises a sensor assembly (170) which detects the force applied to the connecting element (40) during operation and transmitted by the holding arm (30) to the motor vehicle body (12).

81. The device according to claim 80, characterized in that The sensor assembly has at least three, in particular four, deformation sensors (172, 174, 176).

82. The device according to claim 80 or 81, characterized in that The force detection module (100) is arranged in an operating state on a side of the holding arm (30, 30') facing the roadway (44).

83. The device according to any one of claims 80 to 82, characterized in that The force detection module (100) is arranged in an operating state on a side of the holding arm (30, 30') facing away from the roadway (44).

84. The device according to the preamble of claim 40 or any one of claims 40 to 83, characterized in that A force applied to the connecting element (40) during operation and transmitted by the holding arm (30) to the motor vehicle body (12) is detected by an evaluation unit (230) having a sensor assembly (170), the sensor assembly having at least two deformation sensors (172, 174, 176), and the deformation sensors (172, 174, 176, 178) being arranged on at least one deformation transmission element (102) connected to the holding arm (30).

85. The device according to the preamble of claim 40 or any one of claims 40 to 84, characterized in that A force applied to the connecting element (40) during operation and transmitted by the holding arm (30) to the motor vehicle body (12) is detected by an evaluation unit (230) having a sensor assembly (170), the sensor assembly having at least two deformation sensors (172, 174, 176), and all deformation sensors (172, 174, 176, 178) of the sensor assembly (170) being arranged on a common deformation transmission element (102).

86. The device according to any one of claims 79 to 85, characterized in that Each of the at least two deformation sensors (172, 174, 176) detects deformations of the holding arm (30, 30') of different magnitude when one and the same force acts on the connecting element (40).

87. The device according to any one of claims 79 to 86, characterized in that The deformation transfer element (102) is free from relative movement and is thereby rigidly connected to the holding arm (30) in at least two fixing areas (104, 106, 108), and at least one of the deformation sensors (172, 174, 176, 178) is arranged between the fixing areas (104, 106, 108) of the deformation transfer element (102).

88. The device according to any one of claims 79 to 87, characterized in that The deformation transmission element (102) is connected to the holding arm (30) by means of at least three fixing areas (104, 106, 108), and at least one of the deformation sensors (172, 174, 176, 178) is arranged between two fixing areas of each fixing area (104, 106, 108).

89. The device according to any one of claims 79 to 88, characterized in that The deformation transmission element (102) is connected to the holding arm (30) in the fastening region (104, 106, 108) by means of a joining element (114, 116, 118).

90. The device according to claim 89, characterized in that The engagement element (114, 116, 118) is rigidly connected to the holding arm (30) on the one hand and to the fastening region (104, 106, 108) of the deformation transmission element (102) on the other hand.

91. The device according to claim 90, characterized in that The engagement element (114, 116, 118) is integrally formed on the retaining arm.

92. The device according to any one of claims 79 to 91, characterized in that The engagement elements (114, 116, 118) transfer deformations of the holding arms (30) in deformation regions (82, 84) of the holding arms (30) respectively located between the engagement elements (114, 116, 118) to the fixing regions (104, 106, 108) of the deformation transfer element (102).

93. The device according to any one of claims 89 to 92, characterized in that A deformation region (82, 84) of the holding arm (30) is located between two engagement elements (114, 116, 118).

94. The device according to any one of claims 79 to 93, characterized in that The retaining arm (30) has at least two deformation regions (82, 84), the deformation of the deformation regions being transmitted to the fixing regions (104, 106, 108) of the deformation transfer element (102) through the coupling elements (114, 116, 118) arranged on both sides of each deformation region (82, 84), and a deformed region (152, 154, 156) of the deformation transfer element (102) existing between the fixing regions.

95. The device according to claim 94, characterized in that The at least two deformation regions (82, 84) are arranged successively in the extension direction of the holding arm (30).

96. The device according to any one of claims 79 to 95, characterized in that At least one deformation sensor (172, 174, 176, 178) is arranged in a deformed region of the deformation transmission element (102) among the deformed regions (152, 154, 156, 158).

97. The device according to any one of claims 94 to 96, characterized in that Each deformable region (152, 154, 156, 158) is connected to a non-deformable region (144, 146, 148) of the deformation transfer element (102), and the fixing regions (104, 106, 108) are respectively located in a non-deformable region (144, 146, 148).

98. The device according to claim 97, characterized in that The deformed regions (152, 154, 156, 158) are respectively arranged between two regions (144, 146, 148) that are not easily deformed.

99. The device according to claim 97 or 98, characterized in that The regions (144, 146, 148) that are not easily deformed and the regions (152, 154, 156, 158) that are deformed are arranged successively in the deformation direction.

100. The device according to any one of claims 94 to 99, characterized in that The deformed region (152, 154, 156, 158) is configured as a deformation concentration region.

101. The device according to any one of claims 79 to 100, characterized in that Outside the deformed regions (152, 154, 156, 158), the material of the deformation transmission element (102) is designed as a material that is not easily deformed or a material that is not actively deformed.

102. The device according to any one of claims 79 to 101, characterized in that In the deformed regions (152, 154, 156, 158), the material of the deformation transmission element (102) is prone to deformation by shaping, for example by a cross-sectional constriction.

103. The device according to any one of claims 79 to 102, characterized in that The deformation transmission element (102) has, in addition to the deformed regions (152, 154, 156, 158), non-deformed regions (192, 194, 196, 198), and at least one reference deformation sensor (182, 184, 186, 188) is arranged on the non-deformed regions (192, 194, 196, 198).

104. The device according to claim 103, characterized in that Each of the non-deformed regions (192, 194, 196, 198) is made of the same material as the deformed regions (152, 154, 156, 158).

105. The device according to claim 103 or 104, characterized in that The respective non-deformed regions (192, 194, 196, 198) are connected on one side to the less deformable regions (144, 146, 148) of the deformation transfer element (102).

106. The device according to any one of claims 103 to 105, characterized in that The deformation-free regions (192, 194, 196, 198) of the deformation transmission element (102) are designed in the shape of tongues.

107. The device according to any one of claims 103 to 106, characterized in that The non-deformed regions (192, 194, 196, 198) of the deformation transmission element (102) are made of the same material as the deformed regions (152, 154, 156, 158), in particular have the same material thickness.

108. The device according to claims 103 to 107, characterized in that The reference deformation sensor (182, 184, 186, 188) is thermally connected to the deformation transfer element (102).

109. The device according to claim 108, characterized in that The reference deformation sensor (182, 184, 186, 188) is thermally connected to the deformation sensor (172, 174, 176, 178) by means of the deformation transmission element (102).

110. The device according to claim 109, characterized in that In order to achieve optimal thermal connection between each of the deformation sensors (172, 174, 176, 178) and a reference deformation sensor (182, 184, 186, 188) assigned to the deformation sensor, each deformed region (152, 154, 156, 158) equipped with a deformation sensor (172, 174, 176, 178) is thermally connected to a non-deformed region (192, 194, 196, 198) assigned to the deformed region, and the non-deformed region carries the assigned reference deformation sensor (182, 184, 186, 188).

111. The device according to any one of claims 103 to 110, characterized in that The non-deformed regions (192, 194, 196, 198) carrying the respective reference deformation sensors (182, 184, 186, 188) have the same thermal properties as the deformed regions (152, 154, 156, 158) carrying the corresponding deformation sensors (172, 174, 176, 178).

112. The device according to any one of claims 103 to 111, characterized in that The non-deformed regions (192, 194, 196, 198) each carrying the reference deformation sensor (182, 184, 186, 188) have a similar geometry to the deformed regions (152, 154, 156, 158) carrying the deformation sensor (172, 174, 176, 178).

113. The device according to any one of claims 103 to 112, characterized in that The non-deformed regions (192, 194, 196, 198) of the deformation transmission element (102) are made of the same material as the deformed regions (152, 154, 156, 158) of the deformation transmission element (102).

114. The device according to any one of claims 103 to 113, characterized in that At least one temperature sensor (252, 254, 256, 258) for function monitoring is associated with the reference deformation sensor (182, 184, 186, 188).

115. The device according to any one of claims 79 to 114, characterized in that The deformation transmission element (102) is designed similar to a plate, and each of the deformed regions (152, 154, 156, 158) carrying a deformation sensor (172, 174, 176, 178) is designed by a cross-sectional constriction of the deformation transmission element (102).

116. The device according to claim 115, characterized in that The cross-sectional constriction of the deformation transmission element (102) is formed by constricting the surface area of ​​the deformation transmission element (102).

117. The device according to any one of claims 79 to 116, characterized in that The deformation sensor and the reference deformation sensor are designed as strain sensors, in particular as strain gauges.

118. The device according to any one of claims 79 to 117, characterized in that The deformation sensor and the reference deformation sensor are designed as magnetostrictive sensors or optical sensors.

119. The device according to the preamble of claim 40 or any one of claims 40 to 118, characterized in that The retaining arm (30) has a first deformation region (82) and a second deformation region (84) between the first end (32) and the second end (34), wherein when there is a force (Fx) acting in a longitudinal middle plane (18) of the retaining arm (30) parallel to the travel direction (24), the deformation regions are deformed in a manner similar to that when there is a force (Fx) acting in the longitudinal middle plane (18) transverse to the travel direction (24). z ) when the deformation occurs is different.

120. The device according to claim 119, characterized in that When there is a force (F) acting transversely to the longitudinal midplane (18), in particular perpendicularly to the longitudinal midplane (18), y ), the first deformation region and the second deformation region (82, 84) are deformed respectively, and the deformation is related to the presence of a force (F) acting parallel to and / or transverse to the travel direction (24) and in the longitudinal midplane (18). x , F2) when the deformation is different.

121. The device according to claim 119 or 120, characterized in that The first deformation region and the second deformation region (82, 84) are arranged successively in the extension direction of the holding arm (30).

122. The device according to any one of claims 40 to 121, characterized in that Each deformation sensor (172, 174, 176, 178) is connected to an associated reference deformation sensor (182, 184, 186, 188) in a Wheatstone bridge.

123. The device according to any one of claims 40 to 122, characterized in that The evaluation unit (230) has a processor (234) which converts values ​​corresponding to deformations in the deformed regions (152, 154, 156, 158) using conversion values ​​into forces (F x 、F y , F2) of the corresponding values ​​(WFx, WFy, WFz), the converted values ​​are obtained by calibration and stored in the memory (236).

124. The device according to any one of claims 40 to 122, characterized in that Two forces (F x 、F z ), in particular two forces (F x 、F z ), but are transverse to each other, especially perpendicular to each other, and the third force (F y ) is transverse to the longitudinal middle plane (18) of the retaining arm (30), in particular perpendicular to the longitudinal middle plane (18) of the retaining arm (30).

125. The device according to claim 123 or 124, characterized in that Transformed values ​​for force combinations acting on the connecting element (40) in different octaves are stored in the memory (236).

126. The device according to any one of claims 40 to 125, characterized in that In order to determine the deformation, the evaluation unit (230) detects values ​​of deformation sensors (172, 174, 176, 178) and in particular values ​​of reference deformation sensors (182, 184, 186, 188).

127. The device according to claim 126, characterized in that The evaluation unit (230) detects the value of at least one temperature sensor (252, 254, 256, 258) for functional testing of the reference deformation sensor (182, 184, 186, 188).

128. The device according to claim 127, characterized in that The evaluation unit (230) detects the values ​​of the temperature sensors respectively associated with the reference deformation sensors.

129. The device according to any one of claims 40 to 128, characterized in that The retaining arm (30) carries the connecting element (40) at its second end (34).

130. The device according to claim 129, characterized in that The retaining arm (30) and the connecting element (40) form connected parts.

131. The device according to claim 129 or 130, characterized in that The retaining arm (30) is designed as a ball neck and carries the connecting element (40) at the second end (34), the connecting element comprising a connecting ball (43).

132. The device according to any one of claims 40 to 131, characterized in that The holding arm (30') comprises a receiving body (31') for detachably receiving the connecting element (40').

133. The device according to claim 132, characterized in that The receiving body (31') has an insertion receiving portion (33') which is accessible through an insertion opening (35').

134. The device according to claim 132 or 133, characterized in that The connecting element (40') comprises a carrying arm (42').

135. The device according to any one of claims 132 to 134, characterized in that The support arm (42') having the insertion section (45') can be inserted and fixed in the insertion receptacle (33').

136. The device according to any one of claims 132 to 135, characterized in that The carrying arm (42') carries the connecting ball portion (43).

137. The device according to claim 135 or 136, characterized in that The insertion section (45') is received in the insertion receptacle (33') in a form-fitting manner transversely in the insertion direction (E) and is fixed in the functional state in the insertion direction by a form-fitting body (41).

138. The device according to the preamble of claim 40 or any one of claims 40 to 137, characterized in that The holding arm (30) is equipped with at least three deformation sensors (172, 174, 176, 178), which react in different ways to three forces acting on the connecting element (40) in spatial directions transverse to each other, and the at least three deformation sensors (172, 174, 176, 178) send sensor values ​​(M), and at least one component force acting on the connecting element (40) is derived from the sensor values ​​with the help of an evaluation unit (270).

139. The device according to any one of claims 40 to 138, characterized in that The evaluation unit (230) determines the value (WF) of the component force in the spatial direction (x, y, z) x , W.F. y , W.F. z ) 140. The device according to any one of claims 40 to 139, characterized in that The evaluation unit (270) obtains the value (WF) of the force component in the direction of gravity (Z). z ).

141. The device according to any one of claims 40 to 140, characterized in that The evaluation unit (230) determines the value (F) of its force component in the direction of travel of the motor vehicle (10). x ).

142. The device according to any one of claims 40 to 141, characterized in that The evaluation unit (230) determines the value (F) of its force component transversely, in particular perpendicularly, to the vertical longitudinal center plane (18). y ).

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