Tribometer device for determining at least one tribological quantity, control method for regulating a contact force

Abstract

Tribometer device (1000), preferably a rotary friction wear tribometer (1002) or an oscillating friction wear tribometer (1004), for determining at least one tribological quantity (GR) on an inner surface (2000) of a cylindrical component (2002), comprising: - a sample mandrel (1100) that can be inserted into the cylindrical component (2002) with at least one holder (1120) for a sample segment (1140), wherein - the holder (1120) is movable in a measuring direction (RM) towards the inner surface (2000) in order to keep the sample segment (1140) in contact (K) with the inner surface (2000), - a measuring instrument for the metrological recording of at least one tribological quantity (GR), characterized in that - the holder (1120) has a force sensor (1160) for measuring a contact force (FK) acting in the measuring direction (RM) between the sample segment (1140) and the inner surface (2000), wherein the contact force (FK) between the sample segment (1140) and the inner surface (2000) serves to determine the tribological quantity (GR), wherein - the tribometer device (1000) has a number of measuring elements (1430) each with a holder (1120), wherein each measuring element (1430) has a holder (1120) with the force sensor (1160) for a sample segment (1140), and the holder (1120) can be driven by an axially acting actuating means (1240), and - the tribometer device (1000) has a receptacle for the cylindrical component (2002), wherein the receptacle and the sample mandrel (1100) are rotatable relative to each other about a cylinder axis (AZ) of the cylindrical component (2002), and - the tribometer device (1000) has a control device (1400) with a controller (1420), designed to control the contact force (FK) to a target contact force (FKZ) with the actuating means (1240) as the actuating element) and the at least one force sensor (1160) as the measuring element (1430).

Description

[0001] The invention relates to a tribometer device according to the preamble of claim 1. The invention further relates to a control method.

[0002] DE 10 2006 022 349 A1 describes a test device for carrying out tribological investigations of materials in general. A force is applied to the friction partners under investigation, and the frictional force resulting from the relative movement is determined. In the case of a translational drive movement, at least one force sensor is used to measure the frictional force on the preferably stationary test specimen. This sensor can function, for example, piezoelectrically, using strain gauges, or by another suitable measuring principle. In the case of a rotating drive movement, the resulting frictional force is also measured on the preferably stationary test specimen by means of at least one force sensor in the circumferential direction of rotation. Furthermore, the measuring device also serves to determine the test force applied between the friction surfaces.For this purpose, a force sensor for measuring the normal force is preferably arranged on a fastening device of a test specimen.

[0003] A tribometer device for determining a tribological quantity, such as a rotary friction wear tribometer, is well known. Using such tribometer devices, the tribological behavior of components, particularly the inner surface of cylindrical components, can be determined under highly reproducible conditions. This tribological behavior includes, in particular, determining the coefficient of friction between the component and one or more sample segments, which are brought into and held in contact with the component by the tribometer device. The tribometer device is designed to generate relative motion between the component and the at least one sample segment.

[0004] A tribometer device of this type in the form of a rotary friction wear tribometer is known, for example, as model TE 47 from Phoenix Tribology Ltd, Kingsclere, Berkshire, England and is described at http: / / www.phoenix-tribology.com / at2 / leaflet / te47.

[0005] Such tribometer devices—also simply called tribometers—offer the inherent advantage, due to their design with a sample mandrel and attached holders, of determining tribological parameters even in hard-to-reach locations. Such hard-to-reach locations are found particularly on the inner surface of cylindrical components, such as cylinder liners.

[0006] Tribometer devices for determining a tribological quantity still require improvement. This applies in particular to the accuracy in determining at least one tribological quantity and the reliable creation of reproducible conditions during tribological testing.

[0007] It is therefore desirable to improve a tribometer device for determining a tribological quantity with regard to at least one of the aspects mentioned.

[0008] This is where the invention comes in, the object of which is to provide an improved tribometer device for determining a tribological quantity. In particular, the accuracy in determining the at least one tribological quantity and / or the reliable generation of reproducible conditions in tribological investigations are to be improved.

[0009] The problem relating to the tribometer device is solved in a first aspect by the invention with a tribometer device of claim 1.

[0010] The invention relates to a tribometer device, preferably a rotary friction wear tribometer or an oscillating friction wear tribometer, for determining at least one tribological quantity on an inner surface of a cylindrical component, comprising: - a sample mandrel that can be inserted into the cylindrical component, with at least one holder for a sample segment, wherein - the holder is movable in a measuring direction towards the surface in order to keep the sample segment in contact with the surface, - a measuring instrument for the metrological recording of at least one tribological quantity.

[0011] According to the invention, the tribometer device is designed to have the following features: - the holder has a force sensor for measuring a contact force acting in the measuring direction between the sample segment and the inner surface.

[0012] The invention is based on the consideration that determining at least one tribological quantity on the inner surface of a cylindrical component is advantageously possible using a probe mandrel.

[0013] The sample mandrel is inserted into the cylindrical component, and one or more holders are attached to the mandrel. These holders allow a sample segment to be brought into contact with the inner surface and held in that contact. The measuring direction is typically radial, which, in the case of a cylindrical component, is transverse to the surface, and in particular, essentially perpendicular to the surface. This advantageously enables the determination of tribological parameters even in hard-to-reach areas.

[0014] The invention has surprisingly recognized that, despite the limited space available on and within the cylindrical component, a more direct measurement of a tribological quantity, preferably a contact force, offers significant advantages.

[0015] In comparison to the prior art approach – which is obvious due to limited space constraints – of measuring a tribological quantity indirectly, and in particular averaged over several sample segments, a tribometer device according to the invention offers the advantage that the tribological quantity, in particular the contact force, can be determined individually for each sample segment, in particular with a measuring element for each.

[0016] The holder incorporates a force sensor for measuring a contact force acting in the radial direction—preferably with respect to the cylindrical component—between the sample segment and the inner surface; that is, transversely, preferably essentially perpendicularly, to the surface. This advantageously results in a more precise determination of the tribological quantity, which advantageously allows for its assignment to the individual sample segment. This assignment also enables more precise measurement, particularly with regard to the detection of short-term effects such as force peaks, on an individual sample segment—in this respect, each sample segment is assigned a measuring element with a holder and force sensor.

[0017] The fact that the holder has a force sensor also advantageously results in improved controllability of the contact force for one or more, in particular all, sample segments.

[0018] This reduces the dependence on other sensors, in particular a contact force that is only relevant for all contacts together and / or indirectly measuring sensors.

[0019] The invention, by providing the insight into forming a measuring element, makes it possible to attach a force sensor to the holder, so that an acting contact force between, for example, a cylinder liner and a piston ring "simulated" in the measuring setup on the measuring element, in particular by means of a test segment, can be precisely determined.

[0020] Advantageous further developments of the invention can be found in the dependent claims and specify in detail advantageous possibilities for realizing the concept explained above within the scope of the task and with regard to further advantages.

[0021] Preferably, the tribometer device is designed as a rotary friction wear tribometer or an oscillating friction wear tribometer. Preferably, the force sensor is arranged and configured for direct measurement of the contact force in the measuring direction.

[0022] Determining the tribological quantity advantageously includes measuring a frictional force and / or a frictional torque and / or a contact force and / or a coefficient of friction.

[0023] Determining the tribological parameter is particularly advantageous when determining the coefficient of friction at at least one contact between the cylindrical component and at least one sample segment. The coefficient of friction is preferably determined by measuring the frictional force at the at least one contact. Preferably, the frictional force at the at least one contact is determined indirectly by measuring a frictional torque.

[0024] In particular, the frictional force is obtained by multiplying the contact force or a normal force by a coefficient of friction. Accordingly, if the frictional force and the contact force can be determined metrologically, the coefficient of friction for a material pairing, especially between the cylindrical component and the sample segment, can be determined. FR=RN∗μ

[0025] The normal force FN can be approximated by the contact force FK, resulting in: FR'=RK∗μ

[0026] To determine the coefficient of friction, a frictional torque MR generated by the frictional force FR can be used, which counteracts a rotational relative movement between a cylindrical component and a measuring element of the tribometer device. MR=FR∗ZR

[0027] Here, ZR is the radius of the cylindrical component. In the case of a tribometer device with more than one holder, for example three holders, FR is the sum of the frictional forces. MR=∑FRi∗ZR

[0028] According to the formula mentioned above, the sum of the frictional forces can be determined by a sum of contact forces, wherein the sum of the contact forces can advantageously be formed from the contact forces that were measured with the force sensors according to the concept of the invention. MR=μ∗∑FKi∗ZR

[0029] The coefficient of friction can therefore be determined as follows: μ=MR∑FKi∗ZR

[0030] The invention provides that the tribometer device has a receptacle for the cylindrical component. Advantageously, the receptacle and the probe mandrel for generating a rotational relative movement of a measuring element to the cylindrical component are rotatably designed to rotate relative to each other about a cylinder axis of the cylindrical component. In particular, the tribometer device has a drive for generating the rotational relative movement and / or a drive for generating a translational relative movement of the measuring element to the cylindrical component. Advantageously, the translational relative movement occurs along the cylinder axis of the cylindrical component.

[0031] According to the invention, the contact force between the sample segment and the inner surface serves to determine the tribological quantity. In particular, the tribological quantity to be determined is a frictional force and / or a frictional torque, and the contact force between the sample segment and the inner surface serves to determine the frictional force and / or the frictional torque. In a preferred embodiment, the measuring device comprises a dynamometer arranged on the sample mandrel for determining the frictional torque. A frictional force, in particular an averaged frictional force, can advantageously be determined by means of the frictional torque. The frictional force arises, in particular, at one or more contacts between at least one sample segment and the inner surface of the cylindrical component.

[0032] The invention is further developed in that the tribometer device comprises three holders, in particular three measuring elements—i.e., three holders, each with a force sensor and preferably the associated sample segment. The number of three has proven advantageous for the symmetrical generation of contact forces for determining the tribological quantity, especially for determining a coefficient of friction. However, a different number of holders, in particular measuring elements, is possible, which are advantageously arranged uniformly around the circumference of the sample mandrel.

[0033] Advantageously, the holder is pivotably attached to the specimen mandrel by means of a rocker arm on a rotary bearing. The holder is advantageously fixed to the rocker arm, and particularly advantageously integrally connected to it. The pivotability of the rocker arm about the pivot axis of the rotary bearing advantageously allows a measuring movement or contact force to be generated along a measuring direction that approximately corresponds to a movement or force perpendicular to the inner surface.

[0034] The invention provides that the holder can be driven by an actuating means acting in an axial direction. The actuating means can be hydraulically and / or mechanically actuated, in particular a radial and / or axial load-bearing device. Preferably, the actuating means is selected from the group consisting of: a compressed air bellows, a diaphragm, a push rod, an adjusting screw, and a linear motor.

[0035] It has proven advantageous that the actuating means is designed to actuate a number of holders, preferably measuring elements, uniformly and / or simultaneously, in particular three holders, preferably measuring elements, uniformly and / or simultaneously.

[0036] A measuring element preferably comprises a holder with a force sensor for, optionally, a sample segment. In particular, a measuring element consists of a holder, a force sensor, and a sample segment. The tribometer device preferably comprises: - a number of three holders, and - a number of three force sensors, and - a number of three sample segments.

[0037] Optionally, the tribometer device can include a load cell for measuring an axially acting force, in particular one generated by the actuating device.

[0038] The invention provides a control device comprising a controller for regulating the contact force to a target contact force, with the actuating element as the actuator and the at least one force sensor as the measuring element. Preferably, the control device includes a summation display for subtracting a contact force from a target contact force, and more preferably, for subtracting an averaged contact force from an averaged target contact force, in order to determine a contact force deviation. More preferably, the control device includes an averaging display for determining an averaged contact force from at least two measured contact forces.

[0039] The tribometer device is advantageously designed to generate the rotational relative motion by rotating the cylindrical component around the cylinder axis. This allows the sample mandrel to remain stationary during operation, particularly during measurement, thus simplifying wiring and installation.

[0040] In a second aspect, the invention further specifies a control method of claim 11 for solving the problem.

[0041] The control method for controlling a contact force in a tribometer device, in particular a rotary friction wear tribometer or an oscillating friction wear tribometer, for determining at least one tribological quantity, in particular a friction force and / or a friction torque, on an inner surface of a cylindrical component, in particular on an inner surface of a cylinder liner, comprises the following steps: - Inserting a test mandrel into the cylindrical component, - Moving at least one holder for a sample segment in a measuring direction, in particular a radial direction, essentially perpendicular to the surface, wherein the at least one holder is driven by means of an actuating means acting in an axial direction, - keeping the sample segment in contact with the surface.

[0042] The following steps are provided in the control procedure according to the second aspect of the invention: - Measuring a contact force acting in the measuring direction between the sample segment and the inner surface using a force sensor, wherein the force sensor is arranged in or on the holder, - Rules of the contact force, advantageously an averaged contact force, by controlling the actuating device depending on the measured contact force, advantageously the averaged contact force.

[0043] Controlling the contact force involves adjusting a target contact force, in particular an averaged target contact force, by controlling the actuating device depending on the measured contact force, in particular the averaged contact force.

[0044] In a further development of the control procedure, it is provided that an averaged contact force is calculated from at least two measured values ​​of a contact force, in particular for the controlled adjustment of an averaged target contact force.

[0045] The following step is provided for in a further development of the standard procedure: - Generating a relative motion, in particular a rotational relative motion and / or a translational relative motion, between a measuring element of the tribometer device and the cylindrical component. This step is advantageously performed before and during the control of the contact force and particularly preferably also during a subsequent determination of at least one tribological quantity using one or, advantageously, two, three, four or more measuring elements on the tribometer device.

[0046] The control device of the tribometer apparatus according to the first aspect of the invention is configured to carry out the control method according to the second aspect of the invention.

[0047] It should be understood that the tribometer device according to the first aspect of the invention and the control method according to the second aspect of the invention have identical and similar sub-aspects, as set out in particular in the dependent claims. In this respect, for the further development of one aspect of the invention, reference is also made to the further developments of the other aspect of the invention.

[0048] Embodiments of the invention are now described below with reference to the drawings and comparison with the prior art, some of which is also shown. These drawings are not necessarily to scale; rather, where explanatory, they are presented in a schematic and / or slightly distorted form. For further details regarding the teachings directly apparent from the drawings, reference is made to the relevant prior art. It should be noted that numerous modifications and changes concerning the form and details of an embodiment can be made without deviating from the general idea of ​​the invention. The features of the invention disclosed in the description, the drawings, and the claims can be essential for the further development of the invention, both individually and in any combination.Furthermore, the invention encompasses all combinations of at least two of the features disclosed in the description, the drawing, and / or the claims. The general idea of ​​the invention is not limited to the exact shape or detail of the preferred embodiment shown and described below, nor is it limited to an object that would be restricted compared to the object claimed in the claims. For specified dimensioning ranges, values ​​lying within the stated limits are also disclosed as limit values ​​and are freely usable and claimable. Further advantages, features, and details of the invention will become apparent from the following description of the preferred embodiments and from the drawing; this is shown in: Fig. 1A, Fig. 1B schematically and in part a first embodiment of a tribometer device according to the concept of the invention, Fig. 2A, Fig. 2B a second preferred embodiment of a tribometer device according to the concept of the invention, Fig. 3A, Fig. 3B each a view of an advantageous rocker arm with a holder for a sample segment, in particular for the first and / or the second embodiment of the tribometer device, Fig. 4 schematically the structure of a control device, in particular for the first and / or the second embodiment of the tribometer device, for controlling a target contact force in the form of an averaged target contact force, Fig. 5 A diagram to illustrate the control procedure, in which contact forces are plotted over time.

[0049] Fig. Figure 1A schematically and partially shows a first preferred embodiment of a tribometer device 1000 according to the concept of the invention, which is configured as a rotary friction wear tribometer 1002. In other embodiments, the tribometer device can also be configured as a different tribometer, for example, as an oscillating friction wear tribometer 1004. Visible are a sample mandrel 1100 and a cylindrical component 2002, shown here by way of example in the form of a cylinder liner 2220, which can be received in the tribometer device 1000 by means of a receptacle (not shown here). The tribometer device 1000 is configured to generate a translational relative movement BT between the sample mandrel 1100 and the cylindrical component 2002 along a cylinder axis AZ of the cylindrical component, in particular to insert the sample mandrel 1100 into the cylindrical component 2002 for measurement purposes.The tribometer device 1000 is further developed to generate a rotational relative movement BR between the sample mandrel 1100 and the cylindrical component 2002 about the cylinder axis AZ. Advantageously, the cylindrical component 2002 is rotated so that the sample mandrel 1100 can remain stationary during the rotational relative movement BR.

[0050] Fig. 1B shows the one in Fig. Figure 1A shows the sample mandrel 1100 of the tribometer device 1000, but without the cylindrical component 2002. This reveals that the tribometer device has three measuring elements 1430 attached to the sample mandrel 1100: a first measuring element 1430.1, a second measuring element 1430.2, and a third measuring element 1430.3. Specifically, each measuring element 1430 has a holder 1120: the first measuring element 1430.1 has a first holder 1120.1, the second measuring element 1430.2 has a second holder 1120.2, and the third measuring element 1430.3 has a third holder 1120.3. The aforementioned measuring elements 1430 and holders 1120 are arranged evenly distributed around the circumference of the sample mandrel 1100.

[0051] Fig. Figure 2A shows a second preferred embodiment of a tribometer device 1000 based on the aforementioned model TE 47 from Phoenix Tribology Ltd. The embodiment according to the concept of the invention is shown in a cross-sectional view along a kinked cross-sectional plane X, wherein the cross-sectional plane X is in Fig. 2B is shown with a dashed line. In the cross-sectional view in Fig. In 2A, two of the three holders 1120.1, 1120.2, 1120.3 are visible, of which, due to the rotationally symmetrical design, only the first holder 1120.1 with corresponding numbering is described in more detail.

[0052] The embodiment of a tribometer device 1000 is further developed in an advantageous manner according to the concept of the invention, as shown here.

[0053] The first holder 1120.1 is designed to receive a first sample segment 1140.1. The first holder 1120.1 is designed to hold the first sample segment 1140.1 in such a way that it can be brought into contact K, here a first contact K1, with an inner surface 2000 of a cylindrical component 2002. In this case, the cylindrical component 2002 is designed as a cylinder liner 2200, and the inner surface 2000 is designed accordingly as the cylinder inner wall 2220. The first holder 1120.1 is attached to a first rocker arm 1130.1. The first rocker arm 1130.1 is pivotably attached to the sample mandrel 1100 about a first pivot axis 1222.1 via a first rotary bearing 1220.1. The first rotary bearing 1220.1 is designed as a sliding bearing in the present embodiment, but in other embodiments it can also be designed in other ways, for example as a hinge or similar pivotable connection.

[0054] In the embodiment of the tribometer device 1000 shown here—based on the model TE 47 from Phoenix Tribology Ltd.—the holder 1120 has a type of roller 1290, wherein the holder 1120 can be driven in the measuring direction by the actuating device by means of a type of conical transmission disc. The conical transmission disc is here connected to the actuating device as a conical deflection plate 1260—advantageously via a preload spring 1246. By means of the preload spring 1246, a preload can already be applied to the rocker arms without the actuating device having to provide a driving effect. Specifically, it is shown here that a conical deflection plate 1260, which is axially displaceable relative to the specimen mandrel 1100, is arranged on the specimen mandrel 1100. The deflection plate is displaceable by means of the actuating device 1240. In principle, the actuating device can also be implemented using any other suitable and appropriate translation mechanism.

[0055] In the present embodiment, the actuating means 1240 is advantageously provided with a compressed air bellows 1242, which is displaceable or expandable in the direction of at least one rocker arm 1130.1, advantageously all rocker arms 1130. In the present specific embodiment, the actuating means 1240 thus has a compressed air bellows 1242 or is realized by means of the compressed air bellows 1242. In this case, by pressurizing the compressed air bellows 1242 with compressed air, its axial extension can be changed, thereby correspondingly influencing the axial position of the conical deflecting plate 1260, in this case in particular via a preload spring 1246 and a preload section 1248 adjoining it in the direction of the cylinder axis AZ.

[0056] In principle, the actuating device can also be designed differently in another embodiment, e.g., as a hydraulically and / or mechanically actuated actuating device, in particular an actuating device in the form of a radial and / or axial load-bearing device. It has proven advantageous for the actuating device to be designed to actuate a number of measuring elements uniformly and / or simultaneously, in particular to actuate three measuring elements uniformly and / or simultaneously.

[0057] A first deflection roller 1290.1 ​​is rotatably attached to the end of the first rocker arm 1130.1 opposite the first rotary bearing 1220.1. This roller can be brought into rolling contact with the conical deflection plate 1260. When the conical deflection plate 1260 moves axially, the first rocker arm 1130.1, including the first holder 1120.1, pivots about the first pivot axis 1222.1 as the first deflection roller 1290 rolls on the conical surface of the conical deflection plate 1260. This generates a first measuring movement BM1 of the first sample segment 1120.1 in a first measuring direction RM1.

[0058] The first measuring direction RM1 is described by a circular path around the first pivot axis 1222.1. Such a circular measuring direction RM around a pivot axis 1222 represents a relatively good approximation of a radial direction RR, which is ideally sought to generate a normally acting contact force FK. By increasing the axial length of the rocker arm 1130 (i.e., along the cylinder axis AZ), this approximation can be further improved, but this simultaneously increases the axial extent of the tribometer device 1000. Therefore, a compromise must be found between these two target parameters.

[0059] Once the conical deflection plate 1260 reaches a sufficiently high axial position, a first contact K1 occurs with a first contact force FK1 between the first sample segment 1140.1 and the inner surface 2000. The contact K, here the first contact K1, can be point-like, line-like, or planar, depending on the shape of the sample segment 1140, here the first sample segment 1140.1.

[0060] According to the concept of the invention, the first holder 1120.1 has a first force sensor 1160.1 for measuring the first contact force FK1. The first force sensor 1160.1 is advantageously arranged in the first holder 1120.1 such that the first sample segment 1140.1 is positioned between the inner surface 2000 and the first force sensor 1160.1 in the first measuring direction RM1 and / or in the radial direction RR. In other words, the first force sensor 1160.1 is positioned behind, preferably directly behind, the first sample segment 1140.1 in the first measuring direction RM1 and / or in the radial direction RR.

[0061] The above statements apply analogously to the second holder 1120.2 and the third holder 1120.3, or generally a holder 1120 of a tribometer device 1000 according to the concept of the invention, with corresponding numbering.

[0062] With the advantageous design of the tribometer device 1000 shown here, the contact forces FK1, FK2, FK3 can be measured individually and / or as an averaged contact force FKM, and particularly preferably also controlled. For this purpose, the tribometer device 1000 can advantageously include a control unit 1400, which is connected to the force sensors 1160.1, 1160.2, 1160.3 and the actuator 1240, for example via suitable cables, with a signal transmission. In particular, the actuator 1240 can be controlled with a manipulated variable SG.

[0063] The tribometer device 1000 preferably includes a dynamometer 1282, which is configured to determine a frictional torque MR. The frictional torque MR is the torque acting about the cylinder axis AZ, which is generated by the rubbing contact K1, K2, K3 of the sample segments 1140.1, 1140.2, 1140.3 with the inner surface 2000 and opposes the rotational relative movement BR.

[0064] The tribometer device 1000 can optionally also include a load cell 1320 for measuring an axial force FA acting along the cylinder axis AZ.

[0065] Fig. 3A and Fig. Figure 3B shows a view of an advantageous rocker arm 1130 with a holder 1120 for a sample segment 1140. Fig. Figure 3A shows the rocker arm 1130 in a perspective view. The view shows both a pivot bearing mount 1224 for a pivot bearing 1220 (not shown) and a roller mount 1294 for a deflection roller 1290 (not shown).

[0066] Fig. 3B is a side cross-sectional view of the rocker arm 1130, with the cross-sectional plane Y in Fig. Figure 3A shows the arrangement of a force sensor 1160, which is located within the holder 1120 in the measuring direction MR and / or in the radial direction RR behind the sample segment 1140. This advantageously allows for the most direct possible measurement of the contact force FK, which results from contact K between the sample segment 1140 and the inner surface 2000 (not shown). In embodiments, the holder 1120 and the rocker arm 1130 can be formed as a single unit. The holder 1120 is advantageously designed for the force-fit and / or form-fit, releasable fixation of the sample segment 1140. For example, the holder 1120 can be configured to clamp the sample segment 1140 using one or more clamping screws (not shown).

[0067] Fig. Figure 4 schematically shows the structure of a control device 1400, in particular for a system in Fig. 2A, Fig. 2B or Fig. 3A, Fig. 3B shows a tribometer device 1000 for controlling a target contact force FKZ, here in the form of an averaged target contact force FKZM.

[0068] In a summation diagram 1460, an averaged contact force FKM is subtracted from the averaged target contact force FKMZ. The resulting contact force deviation FKD is then fed to a controller 1420. Based on the contact force deviation FKD, the controller determines a manipulated variable SG for the actuator 1240. In this case, the actuator 1240 comprises a compressed air bellows 1242, so the manipulated variable SG can advantageously be configured as a setpoint pressure value, a control timing, or a switching command for a pneumatic valve or compressor.

[0069] As a result of the actuation of the actuator 1240, a first contact K1 occurs between the first sample segment 1140.1 and the inner surface 2000 at the first rocker arm 1130.1 with the first holder 1120.1, a second contact K2 occurs between the second sample segment 1140.2 and the inner surface 2000 at the second rocker arm 1130.2 with the second holder 1120.2, and a third contact K3 occurs between the third sample segment 1140.3 and the inner surface 2000 at the third rocker arm 1130.3 with the third holder 1120.3.

[0070] According to the concept of the invention, the first holder 1120.1 has a first force sensor 1160.1 as a first measuring element 1430.1 for measuring a first contact force FK1 of the first contact K1. The second holder 1120.2 has a second force sensor 1160.2 as a second measuring element 1430.2 for measuring a second contact force FK2 of the second contact K2. The third holder 1120.3 has a third force sensor 1160.3 as a third measuring element 1430.3 for measuring a third contact force FK3 of the third contact K3.

[0071] The average contact force FKM is calculated from the first contact force FK1, the second contact force FK2, and the third contact force FK3 in a mean value diagram 1440. The average contact force FKM is thus a mean value calculated from the three measured contact forces FK1, FK2, and FK3. The average contact force FKM is then provided to the summary diagram 1460.

[0072] In the described manner, a continuous or quasi-continuous control loop can advantageously be implemented to control a contact force FK, in particular - as here in the case of a tribometer device 1000 with several holders 1120 and thus several force sensors 1160 - in the form of an averaged contact force FKM.

[0073] Fig. Figure 5 shows a diagram to illustrate the process of a control, in particular the calculation of an average value using an average value plot 1140. In the diagram, a force F, in particular a contact force FK, is plotted in Newtons against time T in seconds.

[0074] For clarity, only a first measured contact force FK1 of the first force sensor 1160.1 and a second measured contact force FK2 of the second force sensor 1160.2 are shown. However, a third measured contact force FK3 or even further measured contact forces FK can be taken into account analogously during control, particularly during averaging.

[0075] Visible is a target contact force FKZ, here an averaged target contact force FKZM, which is a constant 150 N. Also visible is the curve of the first contact force FK1, which, after an initial force build-up (through the initial extension of the first rocker arm 1130.1), stabilizes at a level slightly below the averaged target contact force FKZM of 150 N. The curve of the second contact force FK2 is also visible, which, after an initial force build-up (through the initial extension of the second rocker arm 1130.2), stabilizes at a level slightly above the averaged target contact force FKZM of 150 N.

[0076] The average contact force FKM, formed from the two contact forces FK1 and FK2, lies accordingly in the middle between the two curves of the first contact force FK1 and the second contact force FK2 and stabilizes – according to the in Fig.4 described function of the control device 1400 - after a time T of approx. 500 seconds at the value of the averaged target contact force FKZM.

[0077] Depending on the setting of the control behavior of the control device 1400, in particular the controller 1420, the temporal behavior of the control device 1400 and thus of the control procedure can be adjusted. In particular, a steeper control behavior can shorten the time in which the contact force FK is regulated to the target contact force FKZ, in particular the averaged contact force FKM to the averaged target contact force FKZM. REFERENCE MARK LIST (Part of the description) 1000 Tribometer device 1002 Rotary Friction Wear Tribometer 1004 Oscillation Friction Wear Tribometer 1100 sample mandrels 1120 holders 1120.1 first owner 1120.2 second holder 1120.3 third holder 1130 rocker arms 1130.1 first rocker arm 1130.2 second rocker arm 1130.3 third rocker arm 1140 Sample segment 1140.1 first test segment 1140.2 second sample segment 1140.3 third sample segment 1160 force sensor 1160.1 first force sensor 1160.2 second force sensor 1160.3 third force sensor 1220 swivel bearings 1220.1 first pivot bearing 1222 Swivel axis 1222.1 first pivot axis 1224 Rotary bearing mount 1240 actuators 1242 Air bellows 1246 Preload spring 1248 Leading section 1260 Deflection plate 1282 dynamometers 1290 pulley 1290.1 ​​first deflection pulley 1294 Roll recording 1320 Load cell 1400 Control unit 1420 controller 1430 measuring element 1430.1 first measuring element 1430.2 second measuring element 1430.3 third measuring element 1440 average images 1460 composite images 2000 interior surface 2002 cylindrical component 2200 cylinder liner 2220 Cylinder inner wall AZ cylinder axis BR rotational relative motion BT translational relative motion FA Axial force FK Contact Person FKD contact force deviation FKM averaged contact force FKZ Target Contact Person FKZM averaged target contact force K Contact K1 first contact K2 second contact K3 third contact MR frictional torque RM measuring direction RM1 first measuring direction RR radial direction SG Control variable T time X Cross-sectional plane X Y cross-sectional plane Y

Claims

[1] Tribometer device (1000), preferably a rotary friction wear tribometer (1002) or an oscillating friction wear tribometer (1004), for determining at least one tribological quantity (GR) on an inner surface (2000) of a cylindrical component (2002), comprising: - a sample mandrel (1100) that can be inserted into the cylindrical component (2002) with at least one holder (1120) for a sample segment (1140), wherein - the holder (1120) is movable in a measuring direction (RM) towards the inner surface (2000) in order to keep the sample segment (1140) in contact (K) with the inner surface (2000), - a measuring instrument for the metrological recording of at least one tribological quantity (GR), characterized by , that - the holder (1120) has a force sensor (1160) for measuring a contact force (FK) acting in the measuring direction (RM) between the sample segment (1140) and the inner surface (2000), wherein the contact force (FK) between the sample segment (1140) and the inner surface (2000) serves to determine the tribological quantity (GR), wherein - the tribometer device (1000) has a number of measuring elements (1430) each with a holder (1120), wherein each measuring element (1430) has a holder (1120) with the force sensor (1160) for a sample segment (1140), and the holder (1120) can be driven by an axially acting actuating means (1240), and - the tribometer device (1000) has a receptacle for the cylindrical component (2002), wherein the receptacle and the sample mandrel (1100) are rotatable relative to each other about a cylinder axis (AZ) of the cylindrical component (2002), and - the tribometer device (1000) has a control device (1400) with a controller (1420), designed to control the contact force (FK) to a target contact force (FKZ) with the actuating means (1240) as the actuating element) and the at least one force sensor (1160) as the measuring element (1430). [2] Tribometer device according to claim 1, characterized by , that the tribological quantity (GR) to be determined is a frictional force (FR) and / or a frictional torque (MR) and the contact force (FK) between the sample segment (1140) and the inner surface (2000) serves to determine the frictional force (FR) and / or the frictional torque (MR). [3] Tribometer device according to claim 1 or 2, characterized by , that - the measuring instrument comprises a dynamometer (1282) arranged on the sample mandrel (1100) for determining a frictional torque (MR). [4] Tribometer device according to any of the preceding claims, characterized by, that the tribometer device (1000) has a number of three measuring elements (1430.1, 1430.2, 1430.3), wherein each measuring element (1430) has a holder (1120) with force sensor (1160) for a sample segment (1140). [5] Tribometer device according to claim 4, characterized by , that the tribometer device (1000) has: - a number of three holders (1120.1, 1120.2, 1120.3), and - a number of three force sensors (1160.1, 1160.2, 1160.3), and - a number of three sample segments (1140.1, 1140.2, 1140.3). [6] Tribometer device according to any of the preceding claims, characterized by , that - the holder (1120) is pivotably attached to the sample mandrel (1100) by means of a rocker arm (1130) on a rotary bearing (1220). [7] Tribometer device according to claim 1, characterized by , that the actuating device (1240) is a hydraulically and / or mechanically actuating device. [8] Tribometer device according to claim 1 or 7, characterized by , that the actuating means (1240) is formed in the form of a radial and / or axial loading device. [9] Tribometer device according to claim 7 or 8, characterized by , that the actuating device (1240) is selected from the group consisting of: a pneumatic bellows (1242), a diaphragm, a push rod, an adjusting screw, a linear motor. [10] Tribometer device according to any of the preceding claims, characterized by , that - the holder (1120) has a deflection roller (1290), wherein the holder (1120) can be driven in the measuring direction (RM) by the actuating means (1240) by means of a conical transmission disc (1260). [11] Control method (400) for controlling a contact force (FK) in a tribometer device (1000) according to one of claims 1 to 10, for determining at least one tribological quantity (GR) on an inner surface (2000) of a cylindrical component (2002), comprising the steps: - Inserting a test mandrel (1100) into the cylindrical component (2002), - Moving at least one holder (1120) for a sample segment (1140) in a measuring direction (RM) towards the inner surface (2000), wherein the at least one holder (1120) is driven by means of an axially acting actuating means (1240), - in contact (K) Keeping the sample segment (1140) in contact with the inner surface (2000), characterized by the steps: - Measuring a contact force (FK) acting in the measuring direction (RM) between the sample segment (1140) and the inner surface (2000) with a force sensor (1160), wherein the contact force (FK) between the sample segment (1140) and the inner surface (2000) serves to determine the tribological quantity (GR) and the force sensor (1160) is arranged in or on the holder (1120), - Control of the contact force (FK) by controlling the actuating device (1240) depending on the measured contact force (FK), wherein a control device (1400) with a controller (1420) controls the contact force (FK) to a target contact force (FKZ) with the actuating device (1240) as the actuating element and the at least one force sensor (1160) as the measuring element (1430). [12] Control method (400) according to claim 11, characterized by, that if more than one contact force (FK, FK1, FK2, FK3) is available, an average contact force (FKM) is controlled by actuating the actuator (1240) in such a way that the average contact force (FKM) is formed from at least two measured values ​​of a contact force (FK, FK1, FK2, FK3) for the purpose of controlling and adjusting an average target contact force (FKZM). [13] Control method (400) according to claim 11 or 12, characterized by the step: - Generating a relative motion (BR, BT) between a measuring element (1430) of the tribometer device (1000) and the cylindrical component (2002). [14] Control method (400) according to claim 13, characterized by , that the relative motion (BR, BT) is a rotational relative motion (BR) and / or a translational relative motion (BT). [15] Control method (400) according to any one of claims 11 to 14, characterized by, that the measuring direction (RM) to the inner surface (2000) is a radial direction (RR) and / or transverse, preferably perpendicular, to the inner surface (2000). [16] Control method (400) according to any one of claims 11 to 15, characterized by , that the inner surface (2000) of the cylindrical component (2002) is an inner surface (2220) of a cylinder liner (2200).

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