A method for correcting misalignment in at least one axis system.

Abstract

The present invention relates to a method (100) for correcting misalignment of at least one shaft system (5, 5a, 5b) of a powertrain (3) on a test bench (1), in which at least one piezoelectric force sensor (4a, 4b, 4c, 4d) is arranged in a force path through which a force flow can be transmitted between a load unit (14; 14a, 14b) of the test bench (1) and the powertrain (3) or a drive unit (2) of the test bench (1) during the transmission of power via the shaft system (5; 5a, 5b) and which performs the following work steps: The present invention relates to a method (100) comprising a step (101) of performing a force measurement perpendicular to at least one plane (A, B; F) intersected by a rotation axis (D) of the axis system (5; 5a, 5b) and preferably at least substantially perpendicular to the rotation axis (D), a step (102) of analysing the measured values ​​or the measured value course of the force measurement in order to detect misalignment of the axis system (5; 5a, 5b), a step (103) of determining target values ​​for a position correction of the load unit (14; 14a, 14b) or the drive unit (2) in order to minimise the misalignment, and a step (105) of outputting the target values.

Description

[[Technical Field]]

[0001] The present invention relates to a method for correcting misalignment of at least one shafting of a powertrain on a test bench, wherein at least one piezoelectric force sensor is arranged in a force path through which a force flow can be transmitted between a load unit of the test bench and the powertrain or a drive unit of the test bench during transmission of power via the shafting. The invention further relates to a test bench on which the method can be implemented. [[Background Art]]

[0002] Misalignment is caused by assembly and manufacturing inaccuracies, subsidence phenomena, and thermal expansion, and results in displacement of rotating bodies. Such displacement has a harmful effect on the function and operating life of rotating bodies. Misalignment gives rise to distorting forces, especially bending moments and compressive forces, on the rotating body and its bearings.

[0003] Patent Document 1 discloses various test benches and measurement arrangements for detecting misalignment on a test bench using a piezoelectric force sensor. The content of this application is also incorporated into the content of the present application by reference. [[Prior Art Documents]] [[Patent Documents]]

[0004] [[Patent Document 1]] WO / 2021 / 011982 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0005] An object of the present invention is to provide a method for detecting and / or correcting imbalance and / or misalignment of a shaft system of an operating powertrain on a test bench and a corresponding powertrain test bench. Means for Solving the Problem

[0006] This object is solved by the independent claim. Advantageous embodiments are claimed in the dependent claims.

[0007] A first aspect of the present invention relates to a method for correcting misalignment of at least one shaft system of a powertrain on a test bench, wherein at least one piezoelectric force sensor is arranged in a force path through which a force flow can be transmitted between a load unit of the test bench and the powertrain or a drive unit of the test bench during power transmission through the shaft system, the method comprising the following working steps: performing force measurement in at least one plane and / or perpendicular to at least one plane intersected by a rotation axis of the shaft system, preferably at least substantially perpendicular to the rotation axis; analyzing the measured values or measured value progression of the force measurement to detect misalignment of the shaft system; determining a target value for position correction of the load unit or the drive unit to minimize the misalignment; outputting the target value; and the method comprising the above steps.

[0008] A second aspect of the present invention relates to a load unit connectable to a shaft system to be tested; at least one piezoelectric force sensor arranged in a force path through which a force flow is transmitted from the load unit of the test bench during power transmission by the shaft system, the at least one piezoelectric force sensor being configured to perform force measurement in a plane and / or perpendicular to a plane intersected by a rotation axis of the shaft system, preferably at least substantially perpendicular to the rotation axis; A means configured to perform force measurement, A means configured to analyze force measurement values ​​or changes in measurement values ​​in order to detect misalignment of the axial system, In order to minimize mismatch, means for determining a target value for position correction of the load unit or drive unit, Means for outputting target values, particularly interfaces and A signal processing device having This relates to a powertrain test bench equipped with [specific features / features].

[0009] Further aspects of the present invention relate to computer programs and computer-readable media. Therefore, the method according to the first aspect of the present invention can be implemented in a computer.

[0010] Within the meaning of the present invention, the target value preferably specifies the direction and amount in which the component to be aligned should be shifted and / or rotated. Furthermore, the target value can also indicate the absolute value of the direction and position in which the component to be aligned should be shifted and / or rotated.

[0011] Within the meaning of the present invention, an axial system comprises one or more rotatably connected axes.

[0012] Within the meaning of this invention, "communicable" preferably means "can be communicated" or "is being communicated."

[0013] Within the meaning of the present invention, force flow is preferably the path of force and / or torque in a mechanical system from the point of application, particularly the point of introduction, to one or more points where the force and / or torque is accommodated by the reaction force and / or reaction moment. Preferably, force flow consists of force, in particular lateral force with respect to the rotational direction of the axis, and torque, in particular torque about the axis of rotation.

[0014] Within the meaning of the present invention, power flow is preferably the power transmission path in a mechanical system from an introduction point to a point or multiple points where power is extracted.

[0015] Within the meaning of the present invention, the piezoelectric measuring element preferably comprises a piezoelectric crystal and charge dissipation or an electrical connection, respectively.

[0016] A mechanical unit within the meaning of the present invention is configured to convert energy, preferably kinetic energy, in particular rotational energy, into electrical energy, or vice versa, or chemical energy into kinetic energy. A mechanical unit within the meaning of the present invention preferably comprises a housing.

[0017] A support device within the meaning of the present invention is preferably a device for supporting an element against forces and / or torques acting on the element. The support device is preferably configured to provide so-called reaction forces or bearing reaction forces. A support device within the meaning of the present invention preferably works to support a bearing device. Preferably, the support device is a bell housing, a powertrain housing, or even a base plate.

[0018] Detection within the meaning of the present invention preferably involves determination and / or quantification and / or localization and / or analysis.

[0019] Means within the meaning of the present invention may be designed as hardware and / or software, in particular as a processing unit, in particular as a digital processing unit, in particular as a microprocessor unit (CPU), in particular as a CPU, which is preferably data-connected or signal-connected to a memory or bus system and / or has one or more programs or program modules. The CPU may be configured to process instructions implemented as a program stored in a memory system, to capture input signals from a data bus and / or to send output signals to the data bus. The memory system may comprise one or more different storage media, in particular as magneto-optical solid-state and / or other non-volatile media. The program may be designed to embody or implement the methods described herein such that the CPU can perform steps of such methods and, therefore in particular, can detect imbalances and / or inconsistencies.

[0020] Within the meaning of the present invention, an incremental encoder is preferably capable of determining individual angular segments and / or full revolutions. In particular, the incremental encoder provides at least one pulse for each rotation.

[0021] The present invention is based, in particular, on a method for adjusting misalignments in the powertrain shaft system on a test bench by force sensors, in particular by force sensors provided to determine torque during test operations on the test bench. Using the present invention eliminates the need for further measuring methods or measuring instrumentation, in particular optical methods commonly used in the prior art.

[0022] In particular, the shaft system does not need to be externally, in other words, separately aligned away from the test bench. Instead, misalignment detection is performed directly on the test bench through the establishment of a frictional connection between the load unit, so-called dyno, and the drive unit. The present invention therefore enables alignment of the shaft system in an assembled state, with all assembly inaccuracies, including unequal screw weights, alignment errors, fit tolerances, and manufacturing errors such as eccentricity, asymmetry, and density errors.

[0023] In the case of correction-required force measurement, the present invention preferably utilizes piezoelectric measuring elements, which enable particularly reliable measurements and, due to their rigidity, add only slight elasticity to the powertrain's vibration system. The piezoelectric measuring elements are preferably permanently mounted on a test bench so that physically impurity-free measurement signals can be recorded. In particular, the measuring elements may be supported by an intermediate plate or a base plate.

[0024] Since physical "force" variables are directly captured, conclusions regarding adverse effects on mechanical components can be drawn. Empirical methods for evaluating the condition of mechanical units are not necessary. Based on the determination of alignment errors by this invention, new standards for mechanical safety can therefore be developed. In addition to gravity, misalignment produces other spatially fixed forces or torques, in other words, those that do not rotate at rotational speed. This invention makes it possible to determine misalignment without additional vibration analysis.

[0025] If the alignment of the axial system changes during operation, the present invention enables this to be detected on the test bench and allows countermeasures, such as an emergency stop or load reduction, to be initiated to prevent permanent damage to the powertrain or even the test bench.

[0026] Furthermore, target values ​​for correcting mismatches are determined inventively. Automated positional compensation of the load unit and / or drive unit can be performed based on these target values. Mismatches can then be minimized or even eliminated directly on the test bench. Target value determination significantly simplifies the configuration or calibration of the measurement setup, which has generally been performed manually using optical methods. In particular, the time required can be reduced by orders of magnitude. The possibility of automation also makes it possible to eliminate the need for highly qualified personnel for these tasks.

[0027] In one advantageous embodiment of this method, the following additional work steps are taken: The steps include determining a bending moment curve for the axial system based on the measured force value or the trend of the measured value, A step of determining the bending line of the axial system based on the determined bending moment curve, taking into account the boundary and connection conditions, wherein the target value is determined through the bending line. This is done in determining the target value.

[0028] In a further advantageous embodiment, the method comprises the following steps: A step to check whether the bending moment or bending moment curve with respect to the axial system exceeds a threshold, The steps include: repeating this method when the threshold is exceeded, or terminating this method when the threshold is not exceeded. To further prepare.

[0029] An iterative process to optimize the alignment of the axial system based on the determined bending moment or bending moment curve allows for particularly precise determination of the target value.

[0030] In a further advantageous embodiment, the method comprises the following steps: The step of separating the frictional connection between the load unit and the drive unit, particularly by opening the coupling of the shaft system. To further prepare.

[0031] Isolating frictional connections makes it particularly easy to change the position of the load unit and / or drive unit.

[0032] In a further advantageous embodiment, the method comprises the following steps: Steps to change the position of the load unit and / or drive unit on the test bench based on the outputted target value. To further prepare.

[0033] Preferably, this position change is automated. More preferably, the test bench is equipped with an adjustment device for that purpose, which is configured to change the position of the load unit or drive unit translationally and / or rotationally.

[0034] In a further advantageous embodiment, the method comprises the following steps: Steps to establish a friction connection between the load unit and the drive unit. To further prepare.

[0035] Preferably, the friction connection is restored following a change in the position of the load unit and / or the drive unit.

[0036] In a further advantageous embodiment of this method, constants of the axial system specific to the test bench, in particular the product of the elastic coefficient and the resistance coefficient, are determined to calculate the bending line through two force measurements at different locations on the drive unit or load unit, respectively.

[0037] This allows the measurement setup to be calibrated without knowing the material properties of the axial system, particularly its stiffness.

[0038] In a further advantageous embodiment of this method, the axis of rotation of the axial system is the axis of rotation of the axis of the axial system on which the force measurement is performed.

[0039] Preferably, the plane on which force measurement is performed is defined by bearing points of the axial system on the mechanical unit on which the force sensor is supported. More preferably, the plane is defined by points on which the force sensor is positioned.

[0040] In a further advantageous embodiment of this method, force measurement is performed when the axial system is stationary or quasi-stationary.

[0041] Within the meaning of this invention, the stationary state of the axial system preferably exists when the axial system is not rotating.

[0042] Within the meaning of the present invention, a quasi-stationary state of the axial system preferably exists when the axial system rotates at an angular velocity such that the response time of the force sensor is relatively short with respect to the rate of change of the rotational position of the axial system. In particular, the force can be measured in a manner that is not affected by dynamics. Preferably, the magnitude of the angular velocity is very small, and its inertial mass has little or no effect, and in particular thereafter, in order to stop, the axial system requires a rotational angle range of about 90°, preferably about 70°, even more preferably about 15°, even more preferably about 10°, and most preferably less than about 5°. Preferably, there is no vibration of the axial system in the quasi-stationary state.

[0043] As a result, mismatch detection may also be performed while the axial system is stationary or near-stationary. This allows for the determination of mismatches even before actual test operation on the test bench. Doing so helps prevent damage to the drive unit under test or the test bench.

[0044] In a further advantageous embodiment of this method, force measurement is monitored such that one or more measurements are compared to a threshold indicating a critical axial load, and when the threshold is exceeded, the rotation of the axial system is stopped or no rotation occurs at all.

[0045] This can also prevent damage to the drive unit or test bench being tested.

[0046] In a further advantageous embodiment of the method, multiple piezoelectric sensors are provided in the force path, and each force measurement of the piezoelectric sensors is monitored.

[0047] In a further advantageous embodiment of this method, the distinction between parallel offset and / or angular offset of the axial system is made during the analysis in relation to the mismatch.

[0048] Features and advantages described below with respect to a first aspect of the present invention are applicable to corresponding further aspects of the present invention, and vice versa.

[0049] In one advantageous embodiment, the powertrain test bench further comprises an adjustment device configured to change the position of the load unit translationally and / or rotationally. Powertrain test benches, particularly those for signal processing devices, A means configured to control the adjustment device based on the outputted target value. To further prepare.

[0050] Further advantages and features will become apparent from the following description of preferred exemplary embodiments with reference to the figures. The figures are shown at least partially schematicly. [Brief explanation of the drawing]

[0051] [Figure 1a] This is a top view of the end face of the load unit, where the shaft of the load unit protrudes. [Figure 1b] This is a side view of the load unit shown in Figure 1a. [Figure 1c]Two top views of a powertrain test bench and a measurement arrangement having a first exemplary embodiment of the load unit shown in Figures 1a and 1b, through which a method for correcting mismatches can be realized. [Figure 2] This is an exemplary embodiment of a method for correcting inconsistencies. [Figure 3] These are four diagrams illustrating the bending lines for force, bending moment, angular misalignment, and parallel misalignment of the axial system on the test bench. [Figure 4] This diagram shows bend lines for parallel misalignment and angular misalignment in the axial direction of the axis system. [Figure 5] This is a top view of a measurement arrangement having a second exemplary embodiment of a powertrain test bench. [Figure 6] This is a top view of a measurement arrangement having a third exemplary embodiment of a powertrain test bench. [Figure 7] This is a top view of a fourth exemplary embodiment of a powertrain test bench. [Figure 8] Figures 1, 5, 6, and 7 show detailed diagrams of the powertrain test bench. [Modes for carrying out the invention]

[0052] Figures 1a, 1b, and 1c show three different views of a first exemplary embodiment of the powertrain test bench 1. Both the view in Figure 1a and the view in Figure 1b show only one load unit 14 of the powertrain test bench 1, while Figure 1c shows two views of a measurement setup having one of the load units 14 described in Figures 1a and 1b and one drive unit 2 under test.

[0053] The alignment of the individual views of Figure 1a, Figure 1b, and Figure 1c relative to each other occurs as a result of the x, y, and c coordinate axes drawn in the respective reference frames.

[0054] Figure 1a shows a top view in the opposite direction of the z-axis on the end face of the load unit 14, where the axis 5b of the load unit 14 protrudes therein. Figure 1b shows a side view of the load unit shown in Figure 1a along the x-axis. The load unit 14 is supported on a base plate or intermediate plate 10 by measuring elements 4a, 4b, 4c, 4d of force sensors. Preferably, the base plate or intermediate plate 10 also supports the measuring elements 4a, 4b, 4c, 4d in the horizontal direction. Preferably, adjustment devices 12a, 12, 12c are provided on the base plate or intermediate plate 10. Preferably, they have a first actuator 12a, a second actuator 12b, and a third actuator 12c to pivot around the x-axis and / or y-axis in order to shift the alignment of the base plate or intermediate plate 10 in the x-axis and / or y-axis direction, and thus also shift the alignment of the load unit 14.

[0055] In Figure 1c, the drive unit 2 and the load unit 14 are connected to or can be connected to the shaft system in a torque transmission manner. The shaft system is not fully depicted in this figure for clarity.

[0056] The left view of Figure 1c shows a measurement configuration in which the mismatch is strictly a parallel mismatch between the axis of rotation D of axis 5b of the load unit 14 and the axis of rotation D' of axis 5a of the drive unit 2 in the x-direction. The right view of Figure 1c shows a measurement configuration in which the mismatch is strictly an angular mismatch between the axis of rotation D of axis 5b of the load unit 14 and the axis of rotation D' of axis 5a of the drive unit 2 around the y-axis. However, generally speaking, the mismatch appears as a superposition of angular and parallel mismatches. Furthermore, the drive unit 2 may also be shifted in the y-direction and / or pivoted around the x-axis, as an addition or alternative. Furthermore, the measurement elements may also be positioned on or within the drive unit 2, as will be further described below with reference to Figures 5, 6 and 7.

[0057] Different planes A, B, F, G, and H are marked in Figure 1c as additional planes. Plane A is a plane that is aligned perpendicular to the rotation axis D of the load unit 14 and has two measuring elements 4a and 4d located on the lower end of the load unit 14 opposite to the axis 5b of the load unit 14. Plane B is similarly a plane that is aligned perpendicular to the rotation axis D of the load unit 14 and has two measuring elements 4b and 4c located on the lower end of the load unit 14 facing the axis 5b of the load unit 14.

[0058] Plane G is a plane that is perpendicular to the rotation axis D' of the drive unit 2 and contains the first bearing of the shaft 5a of the drive unit 2, which is located on the end of the drive unit 2 facing the shaft 5b of the load unit 14. Plane H is similarly perpendicular to the rotation axis D' of the drive unit 2 and contains the second bearing of the shaft 5a of the drive unit 2, which is located on the end of the drive unit 2 opposite to the shaft 5b of the load unit 14.

[0059] The right-hand portion of Figure 1c shows the forces caused by the misalignments depicted in planes A, B, and F. In planes A and B, forces of vectors A and B act on the measuring elements 4a, 4b, 4c, and 4d that support the load unit 14. In plane F, the force of vector F acts on the axial system (not depicted).

[0060] This method, in particular, enables the simultaneous detection and correction of inconsistencies in both the xz and yz planes.

[0061] Furthermore, testbench 1 preferably includes a signal processing device 7 (not depicted), which will be further described below with reference to Figure 8.

[0062] Figure 2 shows an exemplary embodiment of a method for correcting mismatches that may be used in the measurement setups described in Figures 1a to 1c.

[0063] After the installation of the measurement setup, it is preferably first calibrated. In particular, the scaling factor or constant, especially the product of the elastic coefficient and the resistance coefficient for the axial systems 5;5a, 5b, preferably the stiffness constant, is determined for this purpose. This scaling factor or material constant is preferably useful in the calculation of the bend line, as will be further described below with reference to Figure 3. More preferably, the scaling factor or material constant is determined by two force measurements, each at a different relative position of the drive unit 2 and the load unit 14.

[0064] In the first work step 101 of Method 100, force measurement is performed in planes A and B and / or perpendicular to planes A and B. Planes A and B intersect by the axis of rotation D of axis 5b of axis system 5; 5a and 5b, which is the axis of the load unit 14. Preferably, planes A and B are aligned at least substantially perpendicular to the axis of rotation D. Preferably, the axis of rotation D is the axis of rotation of axis 5b of axis system 5; 5a and 5b, by which force measurement is performed, in other words, force is measured, as depicted in Figure 1c.

[0065] More preferably, force measurements are subsequently performed in a stationary or quasi-stationary state of the axial system 5;5a, 5b. As previously described, this makes it possible to prevent damage to the measurement arrangement.

[0066] More preferably, the force measurements are continuously monitored. In particular, each most recently measured value is compared to a threshold indicating a critical load on the axial systems 5;5a, 5b. If this threshold is exceeded, the rotation of the axial systems 5;5a, 5b is stopped or ceased. Furthermore, method 100 is then preferably terminated. Preferably, as depicted in Figure 7, there are multiple force sensors 4, 11 in the force path, and each force measurement of force sensors 4, 11 is preferably monitored in this case.

[0067] A certain constant circumferential lateral force indicates an angular offset in the axial system and can therefore be identified as a misalignment by the method of the present invention.

[0068] In the second work step 102, the measured force values ​​or the changes in measured values ​​are analyzed to detect misalignment between the axis systems 5;5a, 5b. Preferably, a distinction is made between the parallel offset and / or angular offset of the axis systems 5;5a, 5b, thereby in relation to the misalignment.

[0069] In the third work step 103, a target value for position correction of the load unit 14 or drive unit 2 is determined to minimize mismatch. To this end, a bending moment or bending moment curve with respect to the axis systems 5; 5a, 5b is determined in the first substep 103-1, preferably based on measured values ​​or transitions of measured values ​​of force measurements. In the second substep 103-2, preferably the bending lines of the axis systems 5; 5a, 5b are then determined based on the determined bending moment or bending moment curve, taking boundary conditions into consideration. The target value for position correction is then preferably determined using these bending lines. Preferably, the mismatch is measured along the bending line w x The minimum occurs when (z) coincides with the axis of rotation D.

[0070] In the fourth work step 104, a check is performed to determine whether the bending moment or bending moment curve for the axial systems 5;5a, 5b exceeds a threshold. If the threshold is exceeded, method 100 continues and is repeated. A target value is output for this purpose in the fifth work step 105. Preferably, the output is made via the data interface 10 for the next work step. Alternatively or additionally, the target value may be output to the user via the user interface 10.

[0071] When the threshold can no longer be exceeded, method 100 is preferably terminated in the ninth and final work step 109.

[0072] As method 100 continues, the frictional connection between the load unit 14 and the drive unit 2 is preferably disconnected in the sixth work step 106 by opening the (not described) couplings of shaft systems 5; 5a, 5b. The relative positions of the two mechanical units 2, 14 to each other can thereby be changed without canceling out forces.

[0073] In the seventh work step 107, the positions of the load unit 14 and / or drive unit 2 on the test bench are changed based on the outputted target value. This, therefore, results in a reduction of inconsistencies.

[0074] In the eighth work step 108, the friction connection between the load unit 14 and the drive unit 2 is then preferably restored. Preferably, method 100 then restarts in the first work step 101. However, alternatively, method 100 can also restart from the beginning after the previous work steps.

[0075] Referring to Figures 3 and 4, an example calculation of the target value based on forces measured in planes A and B, or in plane F, is described below.

[0076] When the fixedly mounted drive unit 2 and load unit 14 are mechanically connected via the axial system, a frictional connection is established, which can be assumed to be a simplified bent beam (assuming a fixed / floating bearing shaft arrangement as depicted in Figures 1c and 3).

[0077] Depending on the location of the force flow measurement, if shown, the bearing force vectors A and B or the mismatched force vector F can be calculated from the resultant moment equilibrium in planes A and B, or in plane F.

[0078] Force component F for determining mismatch x and F y and force component F z In addition, instant component M bx and M by However, each can be obtained in an essentially known manner through a specific arrangement of the individual measuring elements 4a, 4b, 4c or their piezoelectric elements in a preferred orientation.

[0079] Other methods for determining these parameters may also be used. For example, derived from the measurement signal, in other words, the decomposition of the measurement signal of the measured individual measuring elements 4a, 4b, 4c or the forces F1, .., F i , in particular orthogonal decomposition.

[0080] For example, the M to be determined z , F X , F Y parameters are thereby solutions to a set of equations, whereby an equation of the following form is applied to each measurement signal. S1=a 11 ·M z +a 12 ·F x +a 13 ·F y S2=a 21 ·M z +a 22 ·F x +a 23 ·F y S3=a 31 ·M z +a 32 ·F x +a 33 ·F y SN=a N1 ·M z …

[0081] S1, S2, …Si, …, SN are thereby the measurement signals of the individual measuring elements 4a, 4b, 4c, … 2, N. Each coefficient a depends on a plurality of factors, such as for example the respective position and the respective orientation in the preferred direction of the measuring elements 4a, 4b, 4c, … 4i, 4N in the reference system, the sensitivity of the respective measuring elements 4a, 4b, 4c, …, 4i, … N, and possible signal losses due to a force shunt through the fixing means.

[0082] Torque M z , the first lateral force component F x and the second lateral force component F yTo solve such a set of equations for , measurement signals are required from at least three measurement elements 4a, 4b, and 4c having preferred orientations aligned so as to be in a single plane. Furthermore, at least two of the preferred orientations do not need to be aligned parallel or antiparallel.

[0083] In this general case described for N=3, in other words, the case with three measurement elements 4a, 4b, and 4c, the solution to the set of equations described above is obvious. If further measurement elements are added to the measurement system 1, the set of equations becomes the solution to the three parameters M that must be determined. z F x F y Although it may result in overdeterminism, the measurement accuracy can be further improved.

[0084] For N=4, four different sets of equations F(S1, S2, S3), F(S1, S2, S4), F(S1, S3, S4), and F(S2, S3, S4) can be constructed. The individual parameters M to be determined are... z F x F y The values ​​determined for can then be summed and averaged, or in other words, divided by 4 in the case of four measurement elements 4a, 4b, 4c, ..., 4i, ..., 4N. Similarly, an overdetermined set of equations F(S1, S2, ..., SN) can be constructed to be solved via a minimization problem.

[0085] Once a general solution is found for the set of equations, the parameter M that should be determined is... z F x F y The calculation can be reduced to matrix multiplication. This provides three rows and the same number of columns as the existing measurement signals S1, S2, S3, ..., SN. Each matrix element or coefficient is a parameter M to be determined. z F x F y This describes the contribution of each individual sensor to the given value.

[0086]

number

[0087] Bending moment M bx and M by Furthermore, it can be determined through such decomposition.

[0088] Each parameter M to be determined for the measured signals S1, S2, ...Si, ..., SN z F x F y Decomposition into components that contribute to this requires knowing the positions and orientations of the measurement elements 4a, 4b, 4c, ..., 4i, ..., 4N.

[0089] Geometric parameters can be determined from the design drawings of powertrain test bench 1 and from knowledge of the preferred orientations of measurement elements 4a, 4b, 4c, ..., 2i, ..., 2N.

[0090] The preferred orientation of the measuring elements 4a, 4b, 4c, ..., 4i, ..., 4N may, however, be determined by measuring the preferred orientation using calibration measurements. Preferably, force sensors 4, 11 are fastened between two flat plates for that purpose. In a subsequent step, an external lateral force in a known direction is applied. The preferred orientation of the measuring elements 4a, 4b, 4c, ..., 4i, ..., 4N in the plane spanned by the preferred orientation of the measuring elements 4a, 4b, 4c, ..., 4i, ..., 4N can be determined from the magnitudes of the individual measurement signals S1, S2, ..., Si, ..., SN with respect to the magnitude and direction of the introduced lateral force.

[0091] When the preferred orientation of each individual measuring element 4a, 4b, 4c, ..., 4i, ..., 4N is known, the distance of the measuring elements 4a, 4b, 4c, ..., 4i, ..., 4N from the axis of rotation D is equal to the defined torque M z This can be determined through such a decomposition by applying and measuring the individual measurement signals S1, S2, ...Si, ..., SN.

[0092] As depicted in Figure 3, the bending moment M is determined based on the forces of vectors A, B, and F. by (z) can be determined depending on the location of the load unit 14 in the direction of the rotation axis D, that is, in the direction of the z axis in the given reference system.

[0093] Bent line w x (z) and bending moment M by The relationship between (z) and (z) is, by extension, the following differential equation,

number

[0094] In each case, the differential equation is a polynomial function w x (z) can be solved by the aforementioned polynomial function w x (z) points to the bend line. w represents a series of corresponding polynomials that incorporate each connection condition. x (z) is, in that case, a set of combined differential equations w for multiple axial sections 5a, 5b of the axial system. x This can be determined when solving (z).

[0095] The scaling factor is the curve line w x This can be determined experimentally by specifying boundary conditions for (z). The cases depicted in Figures 1c and 3 are, for example, w x (0) = 0 and w x The boundary condition for (a)=0 is shown. Additionally, the derivative for the angular mismatch with respect to the bend is zero at the point z=a+b in all cases, in other words, w' x(a+b)=0. The scaling factor can then be calculated through two force measurements at different relative positions of the drive unit 2 and the load unit 14. Alternatively, the scaling factor may be estimated through FEM simulation of the axial system or measurement arrangement.

[0096] Figure 4 shows two different bend lines w for the purely angular misalignment of the rotation axes D and D' from Figure 1c (upper part of Figure 4) and the purely parallel misalignment of the rotation axes D and D' from Figure 1c (lower part of Figure 4), determined via the described calculation method. x (z) is shown. In each case, the dotted line indicates the bend line in angular misalignment and parallel misalignment greater than that of the dashed line.

[0097] Of course, the curved line lol y A separate parallel offset in the y-direction and an angular offset due to rotation around the x-axis, resulting in (z), may also occur. 2D curve line w xy (z) can be calculated by superposition in that case. The superposition is preferably the addition of curved lines which are vectors in their orientation, and therefore is a vector addition.

[0098] Figures 5 to 7 show further exemplary embodiments of the powertrain test bench 1. Even if the arrangement of one or more force sensors in these exemplary embodiments deviates to some extent significantly from the arrangement described with respect to the first exemplary embodiment in Figure 1, the calculation of the bending moment and bending line of the powertrain can be reduced to the calculation method described above with reference to Figures 3 and 4.

[0099] Figure 5 shows a second exemplary embodiment of the powertrain test bench 1, which is capable of detecting mismatches in addition to calibration or application tests. In particular, mismatches can be detected independently of the test bench operation.

[0100] Among the various options, powertrain test bench 1 includes load units, namely dynos 14a and 14b, which are rotatably fixed to the powertrain output and connectable in the manner shown in Figure 1.

[0101] The powertrain test bench 1 preferably further comprises an incremental encoder 6 configured to measure the rotation angle of the shaft systems 5a, 5b. The function of the incremental encoder 6 is known from the prior art, and among other things, it can determine the rotation angle or change in rotation angle and / or direction of the shaft systems 5a, 5b photoelectrically, magnetically and / or by sliding contact.

[0102] Furthermore, the powertrain 1 preferably has a force sensor 4, which preferably comprises a plurality of piezoelectric measuring elements, i.e., three piezoelectric measuring elements 4a, 4b, and 4c in Figure 1. The measuring elements 4a, 4b, and 4c are positioned on a measuring flange 12 in the exemplary embodiment shown in Figure 1, which may be part of a powertrain test bench 1 or a powertrain 3. Even more preferably, strain gauges may also be used as measuring elements 4a, 4b, and 4c.

[0103] The measuring flange connects the first shaft section 5a of the powertrain 3 to the second shaft section 5b. The shaft systems 5a and 5b rotate about the axis of rotation D, which is indicated by dashed / dotted lines in Figure 5.

[0104] The drive unit 2 may be either a component of the powertrain test bench 1 or a component of the powertrain 3, depending on which components of the powertrain 3 are to be tested on the powertrain test bench 1.

[0105] In the exemplary embodiment shown in Figure 5, the powertrain 3 comprises a drive unit 2, shaft systems 5a and 5b, a differential 13, and shaft segments (without reference numerals). Power can be transmitted from the drive unit 2 to the load units 14a and 14b via the first shaft section 5a, measuring flange 12, first pressure-power sensor, differential 13, and shaft segments.

[0106] The test bench 1 further comprises the entire drive test bench, the individual elements of the powertrain test bench 1, and / or even a support device 10 on which the powertrain 3 is mounted. The support device 10 can thus provide, for example, a mechanical structure for supporting the individual elements on the floor of the test bench hole. More preferably, the support device 10 may include or be designed to include a base plate.

[0107] In the exemplary embodiment shown in Figure 1, at least the drive unit 2 and power units 14a and 14b are supported by the support device 10.

[0108] Preferably, the power flow generated by the drive unit 2 induces a force flow from the support device 10 through the drive unit 2, the powertrain 3, and the load units 14a and 14b to the support device 10 in the exemplary embodiment shown in Figure 1. The support device 10 thereby provides the respective reaction forces to support the drive unit 2 and the load units 14a and 14b.

[0109] The measuring elements 4a, 4b, and 4c are preferably configured and designed to measure force in the F-plane, in other words, in a plane parallel to the xy-plane of the reference system being depicted. The first force sensor 4 preferably comprises piezoelectric elements 4a, 4b, and 4c that utilize the piezoelectric shear effect. In the exemplary embodiment shown, the force or respective torque on the measuring flange 12 is introduced to the piezoelectric elements 4a, 4b, and 4c via the end faces of the measuring elements 4a, 4b, and 4c. The end faces of the piezoelectric elements 4a, 4b, and 4c are thereby preferably connected to the surface of the measuring flange 12 by friction.

[0110] When there is a force on the measuring flange 12 in the x and / or y directions of the reference system, the piezoelectric measuring elements 4a, 4b, and 4c thus generate a corresponding measurement signal through the piezoelectric shear effect. The same applies when a torque acting in the z direction is applied to the measuring flange 12.

[0111] Alternatively or additionally, measuring elements 4a, 4b, and 4c can enable force measurement perpendicular to the first plane F. For this purpose, measuring elements 4a, 4b, and 4c preferably utilize the piezoelectric longitudinal effect or the piezoelectric transverse effect. When the force is measured both on the first plane F and perpendicular thereto, preferably there are measuring elements capable of measuring the force in the z direction, and measuring elements capable of measuring the force in the x-plane or xy-plane. More preferably, each of the measuring elements 4a, 4b, and 4c comprises at least two piezoelectric elements connected in series with respect to the force flow, so that the first piezoelectric element utilizes the piezoelectric shear effect and the second piezoelectric element utilizes the piezoelectric transverse or longitudinal effect.

[0112] Figure 6 shows a third exemplary embodiment of test bench 1 in which axial misalignment can be detected during test bench operation.

[0113] The substantial difference between the test bench 1 of the third exemplary embodiment from Figure 6 and the test bench 1 of the second exemplary embodiment from Figure 5 is that the force sensor 11 is not placed in the power flow between the drive unit 2 and the load units 14a and 14b, but rather between the support device 10 and the drive unit 2.

[0114] Through this arrangement, the first force sensor 4 measures the reaction force that the support device 10 exerts on the drive unit 2 when it receives torque between the shaft system 5 and the drive unit 2.

[0115] The force sensor 11 may thereby be supported preferably in the axial direction of the rotation axis D, as depicted in Figure 6. However, the drive unit 2 may also be supported laterally, downward, or upward by the force sensor 11, as shown in the top view in Figure 1a, Figure 1b, or Figure 7. Depending on how the piezoelectric measuring elements 11a, 11b, and 11c engage with the drive unit 2, elements having a piezoelectric shear effect, elements having a piezoelectric longitudinal or transverse effect, or elements having two different effects as described above with reference to Figure 5 may be employed in that case.

[0116] Furthermore, in the exemplary embodiment shown in Figure 6, the force is preferably measured in planes C and D and / or perpendicular to planes G and H.

[0117] The second exemplary embodiment shown in Figure 5 can also be combined with the third exemplary embodiment shown in Figure 6. For example, the second exemplary embodiment may therefore have a measuring flange 12 on which an additional pressure-power sensor is mounted. This second pressure-power sensor can then define a second plane F for measuring force and / or moment.

[0118] Furthermore, additional pressure-power sensors may be present for measuring the reaction forces on the load units 14a and 14b, and these additional pressure-power sensors may also preferably support the respective load units 14a and 14b against the support device, in particular against the ground or the base plate 10, thereby allowing the reaction forces between the load units 14a and 14b and the support device 10 to be measured in this case as well.

[0119] Compared to directly measuring the forces in the axial system 5, the reaction force measurement described in Figure 6 has the advantage that each force sensor 4 does not affect the moment of inertia and momentum of the axial system 5.

[0120] A fourth exemplary embodiment of a powertrain test bench in which axial misalignment can be detected is shown in Figure 7.

[0121] The powertrain 3 comprises, when applicable, just one shaft system 5 and one drive unit 2. In contrast to the first exemplary embodiment of the test bench shown in Figure 1, the reaction forces of both the load unit 14 and the drive unit 2 to the support device 10 are preferably measured with respect to at least one measuring plane A, B on the load unit 14 and at least one measuring plane G, H on the drive unit 2.

[0122] However, as with the exemplary embodiments shown in Figures 5 and 6, the powertrain 1 according to the first exemplary embodiment or the second exemplary embodiment may also include further elements, in particular, gear mechanisms or differentials, shaft segments, and the like.

[0123] However, in this exemplary embodiment, each force sensor 4, 11 may be provided having two elements connected in series with respect to the force flow, so that two different measurement directions, in particular two mutually orthogonal measurement directions, are possible. In particular, these measurement directions can be aligned in the y and x directions. The force in the z direction may be measured through a third piezoelectric element in the measuring element of force sensor 4, 11.

[0124] Figure 8 shows details of the powertrain test bench 1 described in Figure 1, Figure 5, Figure 6, or Figure 7, or a separate control unit configured to control the powertrain test bench 1.

[0125] The signal processing device 7 comprises means 8 configured to analyze force measurement values ​​or measurement profiles for detecting mismatches in the axis systems 5; 5a, 5b; means 9 for determining target values ​​for position correction of load units or drive units to minimize mismatches; and means 10, in particular, an interface for outputting target values. More preferably, the signal processing device 7 comprises means 15 for controlling adjustment devices 12a, 12, 12c based on the output target values. The signal processing device 7 is signal-connected to both the measuring elements 4a, 4b, 4c of the force sensors and the adjustment devices 12a, 12, 12c.

[0126] The exemplary embodiments described above are merely examples and are not intended to limit the scope of protection, application, and configuration. Rather, the above description provides guidelines for implementing at least one exemplary embodiment, thereby allowing various modifications to be made without departing from the scope of protection arising from its and equivalent combinations of features claims, particularly with respect to the function and arrangement of the described components. In particular, the individual exemplary embodiments can be combined with each other, particularly with respect to powertrain test benches or measurement arrangements. Thus, in particular, the exemplary embodiments of the powertrain test bench in Figures 5, 6, and 7 may also include adjustment devices 12a, 12b, and 12c. The series of work steps of the described method 100 can also deviate from those depicted. Similarly, force measurement, particularly with respect to axes, can be achieved through sensors based on strain gauges. [Explanation of Symbols]

[0127] 1. Powertrain test bench 2 Drive Unit 3 Powertrain 4. First voltage power sensor 4a, 4b, 4c Piezoelectric measuring elements 5, 5a, 5b axis system 6 Incremental Encoders 7. Signal Processing Devices 8, 9, 10, 15 Means of signal processing devices 11. Second voltage power sensor 12 Measuring flange 13 Differential / Gear Mechanism 14, 14a, 14b Load Units

Claims

1. A method (100) for correcting mismatch in at least one axis system (5, 5a, 5b) of a powertrain (3) on a test bench (1), At least one pressure-power sensor (4a, 4b, 4c, 4d) is positioned in the path of the force that can be transmitted through the power flow between the load unit (14; 14a, 14b) of the test bench (1) and the powertrain (3) or the drive unit (2) of the test bench (1) during the transmission of power via the axial system (5; 5a, 5b), and the following work steps are performed, namely, Step (101) of performing a force measurement in at least one plane (A, B; F) and / or perpendicular to the at least one plane (A, B; F) which is intersected by the axis of rotation (D) of the axial system (5; 5a, 5b) and is at least substantially perpendicular to the axis of rotation (D), Step (102) to detect mismatch in the axial system (5; 5a, 5b), by analyzing the measured value or the trend of the measured value of the force measurement, In order to minimize the aforementioned mismatch, the steps include determining a target value for position correction of the load unit (14; 14a, 14b) or the drive unit (2) (103), Step (105) to output the target value and Equipped with, The following additional work steps, namely, Step (103-1) of determining the bending moment or bending moment curve for the axial system (5; 5a, 5b) based on the measured value or the change in the measured value of the force measurement, Step (103-2) of determining the bending line of the axial system (5; 5a, 5b) based on the determined bending moment or bending moment curve, wherein the target value is determined through the bending line. Method (100) is carried out in the determination of the target value (103).

2. The following are the work steps, namely, Step (104) of checking whether the bending moment or bending moment curve with respect to the axial system (5; 5a, 5b) exceeds a threshold, If the threshold is exceeded, the method (100) is repeated iteratively, or if the threshold is not exceeded, the method (100) is terminated in step (109). The method according to claim 1 (100), further comprising the above.

3. The following are the work steps, namely, Step (106) to separate the frictional connection between the load unit (14) and the drive unit (2) by opening the coupling of the shaft system (5; 5a, 5b). The method according to claim 1 or 2 (100), further comprising the above.

4. The following are the work steps, namely, Step (107) of changing the position of the load unit (14) and / or the drive unit (2) on the test bench based on the outputted target value. The method according to any one of claims 1 to 3, further comprising (100).

5. The following are the work steps, namely, Step (108) to establish a friction connection between the load unit (14) and the drive unit (2) The method according to any one of claims 1 to 4, further comprising (100).

6. The method according to any one of claims 1 to 5 (100), wherein the constants of the axial system (5; 5a, 5b), in particular the product of the elastic coefficient and the resistance coefficient, are determined to calculate the bending line through two force measurements at different positions of the drive unit (2) or the load unit (14).

7. The method according to any one of claims 1 to 6 (100), wherein the rotational axis (D) of the axial system (5; 5a, 5b) is the rotational axis of the axis of the axial system (5; 5a, 5b) on which the force measurement is performed.

8. The method according to any one of claims 1 to 7 (100), wherein the force measurement is performed in a stationary or quasi-stationary state of the axial system (5; 5a, 5b).

9. The method according to any one of claims 1 to 8 (100), wherein the force measurement is monitored such that one or more measured values ​​are compared to a threshold indicating a critical axial system (5; 5a, 5b) load, and if the threshold is exceeded, the rotation of the axial system (5; 5a, 5b) is stopped or not performed.

10. The method according to any one of claims 1 to 9 (100), wherein a plurality of force sensors (4, 11) are provided in the path of force, and each force measurement of the force sensors (4, 11) is monitored.

11. The method according to any one of claims 1 to 10 (100), wherein the distinction between parallel offset and / or angular offset of the axial system (5; 5a, 5b) is made during the analysis with respect to the mismatch.

12. A computer program, when executed by a computer, includes instructions that prompt the computer to perform a step of the method according to any one of claims 1 to 11.

13. A computer-readable medium on which the computer program described in claim 12 is stored.

14. Powertrain test bench (1), Load units (14a, 14b) that can be connected to the axis system under test (5; 5a, 5b), At least one pressure-power sensor (4a, 4b, 4c, 4d) is positioned in the path of force transmitted from and through the load units (14a, 14b) of the powertrain test bench (1) during the transmission of power through the axial system (5; 5a, 5b), and is configured to perform force measurements perpendicular to the plane (A, B; F), intersected in a plane (A, B; F) and / or by the axis of rotation (D) of the axial system (5; 5a, 5b), and at least substantially perpendicular to the axis of rotation (D), - A means (8) configured to analyze the measured values ​​or changes in the measured values ​​of the force measurement in order to detect mismatch in the axial system (5; 5a, 5b), - Means (9) for determining a target value for position correction of the load unit or drive unit in order to minimize the aforementioned mismatch, - Means (10) for outputting the target value, particularly the interface and A signal processing device (7) having A powertrain test bench (1) equipped with the following.

15. The powertrain test bench (1) further comprises adjustment devices (12a, 12b, 12c) configured to change the position of the load units (14a, 14b) or the drive units (2) in a translational and / or rotational manner. The powertrain test bench (1), in particular the signal processing device (7), - Means (15) configured to control the adjustment device (12) based on the outputted target value. Furthermore, The powertrain test bench (1) according to claim 14.

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