EP3114449A1

EP3114449A1 - Component with at least one measuring element comprising a sensor

Info

Publication number: EP3114449A1
Application number: EP14827715.5A
Authority: EP
Inventors: Jens Heim
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2014-03-05
Filing date: 2014-12-05
Publication date: 2017-01-11
Also published as: CN106461479B; DE102014204025A1; CN106461479A; US20170016786A1; US10302512B2; WO2015131862A1

Abstract

The invention relates to a component (1, 10, 14, 19) with a material recess (2, 16, 20) and a measuring element (3, 11, 17, 23, 25, 32, 37, 38, 42,45, 48, 57, 62) comprising at least one sensor (4, 13, 18, 22, 27, 28, 29, 33, 34, 36, 40, 43, 46, 47, 49, 50, 51, 52, 53, 63) which is adapted in a positive fit in the material recess (2, 16, 20). Said sensor (4, 13, 18, 22, 27, 28, 29, 33, 34, 36, 40, 43, 46, 47, 49, 50, 51, 52, 53, 63) is arranged in such a manner in or on the measuring element (3, 11, 17, 23, 25, 32, 37, 38, 42, 45, 48, 57, 62) such that the measuring direction of the sensor (4, 13, 18, 22, 27, 28, 29, 33, 34, 36, 40, 43, 46, 47, 49, 50, 51, 52, 53, 63) essentially corresponds to the action line of the contact angle.

Description

Name of the invention

Component with a sensor element having at least one sensor description

FIELD OF THE INVENTION The invention relates to a component having a material recess and a measuring element having at least one sensor, which is frictionally fitted into the material recess.

Background of the invention

To determine the stress on components during operation, forces and deformations acting on the component are measured. As sensors for detecting component loads, for example, load cells or strain gauges (DMS) are used. Strain gauges are usually glued directly to the component to be measured. However, the attachment of such sensors is expensive in a mass production, since the strain gauges must be individually secured and cabled with an adhesive on a surface. In DE 10 201 1 087 471 A1, a component with a sensor for measuring its load has already been proposed. This component has a material recess into which a measuring element designated as a material element is fitted in a force-fit manner, which has a sensor. The component whose load is to be measured and which may, for example, be a shaft, a bearing ring or the like, is prefabricated by producing the material recess. As part of the production or assembly of the component is then the sensor having used pre-assembled measuring element inserted into the recess, so that the original state of the component is largely retained.

However, it is desirable to further improve the signal quality of measurements. In particular, a greater sensitivity, a lower hysteresis and a better distinguishability of different load directions are desired.

Summary of the invention

The invention is therefore based on the object to provide a component which allows a better differentiation of different load directions.

To achieve this object, it is provided according to the invention in a component of the type mentioned that the sensor is arranged on or on the measuring element, that the measuring direction of the sensor substantially coincides with the line of action of the pressure angle.

The invention is based on the finding that the differentiation of load directions is facilitated if the sensor or its measuring direction is arranged in a certain way, namely such that the measuring direction of the sensor coincides with the line of action of the pressure angle. It is sufficient if the measuring direction of the sensor approximately coincides with the line of action of the pressure angle, especially since the pressure angle is subject to changes during operation as a function of external loads.

The component according to the invention makes it possible to position at least one sensor directly in the force path with maximum load. This force path with maximum load corresponds to the line of action of the pressure angle or the operating pressure angle. This operating pressure angle is due to the external load of the component in a certain range around the constructive nominal pressure angle. With the knowledge of the pressure angle or the operating pressure angle, therefore, the invention makes it possible to determine the relationship between to close between axial load and radial load. If the amount of the load is known, radial loads and axial loads can be determined separately and output in absolute sizes by means of the measuring element. The component preferably closes off the material recess flush at least on one side.

The component according to the invention can be a shaft or a bearing in which the exact determination of attacking axial or radial loads must be monitored. The sensor of the component according to the invention can be a strain-sensitive or pressure-sensitive element of the following group: strain gauges (DMS), thin-film strain gages, piezo element, piezo film, fiber Bragg grating, polymer optical fiber sensor, load cell. A development of the invention provides that on or in the measuring element of the component, a further sensor is arranged rotated by 90 ° to the first sensor. In this embodiment, both sensors are on the same plane, wherein the two sensors are arranged rotated by 90 ° to each other. Such an arrangement enables a temperature compensation of a sensor, in particular a strain gauge. Similarly, a measuring bridge comprising four sensors can be arranged on or in the measuring element of the component according to the invention. Such measuring bridges, which are also referred to as full bridges, allow a particularly accurate detection of an elongation based on changes in resistance.

A particularly preferred embodiment of the component according to the invention provides that the at least one sensor is arranged on or on a bevelled surface of the measuring element, which is aligned with the line of action of the pressure angle. It is particularly preferred that the beveled surface is aligned parallel to the line of action of the pressure angle or that the line of action of the pressure angle extends along the chamfered surface. In this way, a particularly accurate measurement of an elongation along the line of action can take place. By means of the known modulus of elasticity of Material of the measuring element can be determined on the basis of the detected strain, the attacking force. Typically, the measuring element consists of steel. Further embodiments of the invention can provide that the measuring element is arranged axially or radially or obliquely to the axial and / or radial direction in the component. In this way, various possibilities are created which allow an adaptation of the arrangement of the measuring element or the sensor to different directions of force. For each application, an optimal position of the measuring element can be determined in this way.

It is also within the scope of the invention that the sensor is arranged on or on the measuring element such that the measuring direction of the sensor substantially coincides with the line of action of the nominal pressure angle or the operating pressure angle.

In the case of the component according to the invention, it is also conceivable that the measuring element has a plurality of sensors arranged in parallel planes. In this way, the angular position of the line of action of the pressure angle can be detected, so that not only the amount of component load, but also their direction can be detected.

In this connection, it may be provided that a parallel plane has a plurality of sensors which are twisted relative to each other or arranged orthogonally. The arrangement of the sensors at a certain angle allows the detection of the direction of an attacking external load.

A variant of the invention provides that the measuring element has a plane parallel to the axial direction, on which a plurality of sensors are arranged side by side. The sensors can be arranged on the plane next to one another or axially behind one another in order to acquire measured values at different locations. The parallel plane can either be defined by the velvet length of a component, which may be formed, for example, as a shaft extend, alternatively, the parallel plane may also extend only over a portion of its length. Of course, arranged on the parallel plane sensors may be supplemented by other sensors, for example by one or more sensors on the axial end face.

A similar variant provides that a plurality of sensors are arranged on an outer surface of a cylindrical component, the plurality of sensors can either be aligned side by side parallel to the circumference, but they can also be arranged at an angle, that is obliquely to the circumferential direction. In this way, a detection of sensors to the line of action of the pressure angle of the component, in particular a bearing, take place.

Finally, two or more sensors can also be arranged in mutually rotated by 90 ° planes. In this case, one sensor, two sensors or a plurality of, for example, four sensors can be arranged on one level in order to compensate for disturbances such as temperature influences.

In addition, all described arrangements can be combined with each other to allow differentiation of different load directions. In this case, a balance between the quality of the measurement signals and the manufacturing costs is required.

In the context of the invention it can also be provided to push or clamp sensors, in particular strain sensors such as strain gauges, orthogonally. In the case of a component according to the invention, a measuring element with a plane parallel to the axial direction can be provided with orthogonally-pressed sensors, the measuring element being in two parts and having a first part having the parallel plane and a second, complementary part, the sensors being between the two parts are arranged. Also, there are different combinations of different Measurement levels and sensors possible to enable the desired separation of force components.

The measuring element comprising the first part and the second part may be divided in the middle, along a plane of symmetry, so that the sensors are arranged centrally. On the other hand, the measuring element can also be divided eccentrically, so that one part is larger than the other part. In this embodiment, the sensors are eccentrically loaded orthogonally. A further embodiment of the invention provides that the component has a means for tracking a measurement plane, wherein the means is designed so that the sensor is moved to the position of the maximum measurement signal. This automatically resulting position is a measure of the pressure angle resulting during operation. The sensor can be moved to rotate or translate.

Short description of the character

An embodiment of the invention is illustrated in the drawing and will be described in more detail below. Show it:

FIG. 1 shows a detail of a component according to the invention;

Figure 2 shows a detail of another embodiment of a component according to the invention;

FIG. 3 shows a detail of a component with a radially arranged measuring element; FIG. 4 shows a detail of a further exemplary embodiment with an obliquely arranged sensor; Figure 5 is a view similar to Figure 1 with drawn lines of action of the nominal pressure angle and the operating pressure angle;

characters

6 - 7 embodiments of cylindrical measuring elements;

Figures Embodiments of cylindrical measuring elements, in which

8 - 13 sensors are arranged on an inner plane; Figures Embodiments of cylindrical measuring elements, in which

14 - 17 the sensors are pressed orthogonally between two parts of the measuring element;

FIG. 18 shows an exemplary embodiment with a trackable measuring element;

and

Figure 19 shows typical courses of sensor data, wherein the strain on the

Total force is applied.

Detailed description of the drawing

Figure 1 shows a detail of a component 1, which is designed as a rolling bearing and has a cylindrical material recess 2, in which a measuring element 3, which has a sensor 4 is located. The sensor 4 is designed as a strain gauge (DMS) and has cable 5, which are connected to a Meßwerterfas- sanlage.

The formed as a rolling bearing member 1 comprises an inner ring 6, an outer ring 7 and arranged therebetween rolling elements 8. In Figure 1 it can be seen that the measuring element 3 is cylindrical or formed as a bolt. During operation of the rolling bearing this is acted upon by external forces. In Figure 1, the line of action 9 of the nominal pressure angle is shown in dashed lines. The sensor 4 is arranged on the measuring element 3 such that the measuring direction of the sensor substantially coincides with the line of action 9 of the pressure angle. Accordingly, the sensor 4 is located directly in the power flow or at the point at which the power flow is maximum.

It is possible to mount another sensor 4 turned by 90 ° to the sensor 4 on the same surface of the measuring element 3, in order to enable a temperature compensation. Likewise, four such sensors, which are connected to a measuring bridge (full bridge), be arranged on the corresponding surface of the measuring element 3.

Figure 2 is a similar embodiment and shows a component 10 which is designed in accordance with the first embodiment as a rolling bearing. Matching components are designated by the same reference numerals as in the first embodiment. The outer ring 7 has the Matenalausnehmung 2, in which the measuring element 1 1 is inserted. In contrast to the first exemplary embodiment, the measuring element 1 1 has an inclined surface 12 on which a sensor 13 is arranged. The trained as Dehnmessstreifen sensor 13 is thus arranged obliquely with respect to a radial plane of the component 10. The sensor 13 is arranged on the measuring element 1 1, that the line of action 9 of the pressure angle coincides with the position of the sensor 13. With the measuring arrangement shown in FIG. 2, a more accurate measurement result than with the measuring arrangement shown in FIG. 1 can be obtained.

FIG. 3 is a further exemplary embodiment and shows a component 14 which is designed as a roller bearing and which has an outer ring 15 provided with a material recess 16. The material recess 16 into which a measuring element 17 is inserted is positioned so that the line of action 9 of the nominal pressure angle intersects a sensor 18 of the measuring element 17. In the component 14 designed as a spherical roller bearing, the measuring element 17 is thus introduced radially into the material recess 16 of the outer ring 15. The measuring element 17 has on one side a radial groove 61, which serves as a guide for the cable 5. FIG. 4 shows a further exemplary embodiment of a component 19 designed as a roller bearing, in which a material recess 20 is introduced obliquely into the outer ring 21, so that the line of action 9 of the pressure angle intersects the sensor 22 of the measuring element 23. FIG. 5 is a similar embodiment to FIG. 1, therefore the same reference numerals as in FIG. 1 are used for matching components. The line of action of the nominal pressure angle is designated by the reference numeral 9 and shown in dashed lines, the line of action of the operating pressure angle 24 is shown as a solid line. The sensor 4 can thus be positioned on the line of action 24 of the operating pressure angle corresponding to a known ratio of axial load and radial load or corresponding to an operating pressure angle which is of particular interest for the evaluation. In FIG. 5 it can be seen that the line of action 9 of the nominal pressure angle and the line of action 24 of the operating pressure angle can differ from one another.

The measuring elements or measuring bolts can basically be introduced in any direction in the material recess, such. B. in the embodiments shown in FIGS 1 to 5 is shown.

In this case, an axial positioning, which is illustrated for example in FIGS. 1, 2 and 5, is preferred, since signal propagation via a cable guide or a mounted telemetry unit or via an electromagnetic or capacitive coupler can then be implemented particularly easily.

The strain-measuring sensors can directly into the power flow between the component, in particular between a rolling element and a lateral surface a bearing can be introduced without a disturbing cavity arises in the power flow path.

Such an example is shown in FIG. 4, where it can be seen that the force flux line 9 extends directly through the region of the measuring element 23 which is provided with the sensor 22. The cavity formed between the sensor 22 and the material recess, however, is not in the power flow.

Similarly, FIG. 3 shows an exemplary embodiment with a radially introduced measuring element 17, in which the force flux line 9 extends through a cavity which is formed between the inner end of the material recess 16 and the sensor 18. The measuring element 17 is in the power flow, although a small gap or gap between the sensor 18 and the material recess 16 is present.

FIG. 6 is an exemplary embodiment of a measuring element 25, which is designed as a cylindrical bolt and in principle coincides with the measuring element 3 of the preceding exemplary embodiments. At an axial end face 26 of the measuring element 25 is designed as a strain gauge senor sor 27 is attached. In addition, the measuring element 25 has two further sensors 28, 29, which are arranged in the interior of the measuring element 25 on the end face 26 parallel planes 30, 31. All sensors 27, 28, 29 are connected to cables or lines, which are not shown in Figure 6 for reasons of clarity. The strain-measuring sensors 27, 28, 29 arranged in a plurality of planes 26, 30, 31 which are parallel to one another are suitable for detecting the angular position of the line of action of the pressure angle. Thus, not only the amount of the loads acting on the bearing, but also their direction can be detected and distinguished. Optionally, the rear end face concealed in FIG. 6 can also have one or more sensors.

FIG. 7 is a further exemplary embodiment of a measuring element 32 which, like the exemplary embodiment of FIG. 6, has a plurality of planes 26, 30, 31. wherein sensors are mounted on the end face 26 and the inner parallel planes 30, 31 which are parallel to the end face 26. Two sensors 33, 34 designed as strain gages are respectively arranged on the planes 26, 30, 31, wherein the two sensors 33, 34, which are located in the same plane, are arranged rotated by 90 ° with respect to one another.

Figure 8 is another embodiment of a measuring element 37 having a plane 35 on which a plurality of sensors 36 are arranged in the axial direction next to each other. The arrangement shown in Figure 8 is adapted to detect the angular position of the line of action of the pressure angle, whereby not only the amount of stress on a component, such as a rolling bearing, but also their direction can be detected and distinguished. In other embodiments, the plane may also extend only over part of the length of the measuring element.

FIG. 9 is a view similar to FIG. 8 and shows a measuring element 38 in which a plane 39 on which the sensors 36 are arranged extends only over a section in the axial direction. Similarly, FIG. 10 shows the measuring element 38 of FIG. 9, which has a sensor 40 on its axial end face 41 in addition to the sensors 36 on the plane 39.

Figure 1 1 shows a similar embodiment of a measuring element 42, in which the sensors 43 are arranged in the interior of the measuring element 42 on a plane 44. With respect to the center sensor, the left sensor is arranged rotated in the clockwise direction, the right sensor is arranged rotated in a counterclockwise direction on the plane 44. In this way, alignment and position of the sensors 43 can be adapted to the pressure angle or a pressure angle range. The sensors or an imaginary line of symmetry of the sensors 43 in the embodiment of FIG. 11 are adapted along different operating pressure angles, so that the lines of action of different operating pressure angles each intersect a sensor 43. FIG. 12 is an exemplary embodiment of a measuring element 45, in which two sensors 46, 47 are arranged on two planes 41, 44 rotated by 90 ° relative to one another.

FIG. 13 is an exemplary embodiment of a measuring element 48 in which two sensors 49, 50 offset by 90 ° from one another are arranged on the end face 41. In addition, on the inner plane 44, a total of four sensors 51 are arranged in two rows and two columns, wherein adjacent sensors are offset by 90 ° to each other.

Depending on the interconnection, it is possible with these sensors 51 to compensate for disturbances such as temperature influences or to distinguish load directions. At this point, it is expressly pointed out that all appropriate combinations of the previously described embodiments are considered essential to the invention.

FIG. 14 is a further exemplary embodiment of a measuring bolt which has orthogonally pressed sensors 53 which are arranged on a plane 54 in the interior of the measuring element 52. The sensors 53 are associated with lines 55 for the measured value.

FIG. 15 is a similar illustration showing the measuring element 52, which additionally has a second part 56 which is complementary to the first part shown in FIG. 14, so that the two parts together form the cylindrical measuring element 52. The sensors 53 are arranged on the parting plane 54 so that they are pressed or clamped between the two parts of the measuring element 52. Different measuring planes and measuring points may be provided in the measuring element 52 in order to enable a separate detection of expansion and force components. Figure 16 is a view similar to Figure 14 and shows a measuring element 57 in which a parting plane 58 passes through an imaginary center. The second part of the measuring element 57 is thus identical to the first part.

FIG. 17 shows, analogously to FIG. 15, the sensors 53 clamped between the two parts of the measuring element 57.

In the case of the component which has one of the measuring elements described, the measuring plane, that is to say the plane in which the at least one sensor, in particular the strain gauges, is located, can be tracked in order to obtain information about the angular bearings of the operating pressure angle. For this purpose, the strain-detecting sensor is moved to the position in which the maximum measurement signal is detected. The then adjusting position of the measuring element is a measure of the operating pressure angle. The measuring element is for this purpose coupled to an actuator which is designed to rotate the measuring element about its longitudinal axis or to displace it along its longitudinal axis.

FIG. 18 shows a measuring element 62 with sensors 63 mounted on a plane 64. A trained as a drive actuator 65, which is designed as an electric motor is connected via a shaft 66 with a spindle 67. The spindle 67 meshes with a matching internal thread 68 of the measuring element 62. By means of a corresponding control (not shown), the measuring element 62 is displaced in each case by means of the drive 65 into that position at which the measuring signal supplied by the sensors 63 is maximum. The position of the measuring element 62 with respect to an initial state is then a measure of the pressure angle. The measuring element 62 can be displaced in the longitudinal direction. There are also other embodiments conceivable in which the measuring element is rotatable about its longitudinal axis.

The measured data recorded by means of the sensors, in particular by means of the strain sensors, are dependent on the bearing load and the position of the rolling bodies. Therefore, the measured values are averaged, which can also take place in a sliding manner, whereby the dependence of the measured values on the rolling body position is eliminated. The window width of the averaging is selected such that it corresponds at least to the length of a signal period of a rolling element passing by the sensor. It has been found that the averaged sensor data show some dependence on the global deformation of the bearing ring. This global deformation of the bearing ring is dependent on further boundary conditions, for example on how the bearing is installed and by what external forces the bearing was previously loaded. Therefore, the sensor signal shows a certain hysteresis, after a discharge, the strain signal is not completely back to an initial value. In order to minimize these disturbing influences, a signal processing is selected in which to dispense with an averaging. In this case, an evaluation of the signal swing is preferred, as this eliminates the mean value of the raw signal. The signal swing of a plurality of signal periods can in turn be subjected to an optionally moving averaging in order to equalize influences of non-circular rolling element rolling tracks or unequal rolling element diameters. In applications where the bearing rotates rapidly with respect to a load change, it is advantageous to choose the window width of the averaging of the signal strokes as an integer multiple of the number of rolling elements. The evaluation of the signal swing provides a higher sensitivity than the evaluation of the sensor data processed by the averaging, as shown in FIG. On the horizontal axis, the total force is plotted, on the vertical axis, the strain is applied. Reference numeral 59 denotes sensor data obtained by averaging, and 60 denotes sensor data obtained by evaluating the signal swing. Evaluation of the signal swing provides greater sensitivity with reduced hysteresis. The average evaluation does not return completely to the starting point.

As an aid for positioning a measuring element or measuring bolt, a machine element can be used which has a stop for positioning with respect to the axial contact surface of a bearing ring. The return spring travel of the measuring element or the measuring bolt can be kept by a suitable design of the stop. However, manufacturing-related tolerance influences remain with respect to the position of the strain-measuring sensor with respect to the pressure angle of the component, in particular of the bearing.

A reduction of the remaining tolerances can be achieved by the measuring element is not placed on the axial abutment surface (end face), but by an aid is inserted into the raceway of the bearing ring whose axial position is determined by the production pressure angle of the bearing ring. The measuring element or the measuring pin is then positioned on this aid.

As a result, influences of rolling elements are disregarded, since they are replaced by the aid. In order to eliminate or further minimize the remaining tolerances, strains are measured during the crimping process. In this case, the bearing or the bearing ring is loaded via the rolling elements or over Ersatzwälzkörper. The load on the bearing can also be effected in such a way that an operating pressure angle is created which pierces the planned sensor position laterally offset. It is also advantageous that the measuring bolt or the measuring element is pressed in until the measured elongation of a previously selected measuring point has exceeded a maximum.

LIST OF REFERENCE NUMBERS

1 component

2 material recess

3 measuring element

4 sensor

5 cables

6 inner ring

7 outer ring

8 rolling elements

9 line of action

10 component

1 1 measuring element

12 area

13 sensor

14 component

15 outer ring

16 material recess

17 measuring element

18 sensor

19 component

20 material recess

21 outer ring

22 sensor

23 measuring element

24 line of action

25 measuring element

26 face

27 sensor

28 sensor

29 sensor

30 level

31 level measuring element

sensor

level

sensor

measuring element

level

sensor

face

measuring element

sensor

level

measuring element

sensor

measuring element

sensor

parting plane

management

part

measuring element

parting plane

reference numeral

groove

measuring element

sensor

level Drive shaft

Spindle internal thread

Claims

claims

1 . Component (1, 10, 14, 19) having a material recess (2, 16, 20) and at least one sensor (4, 13, 18, 22, 27, 28, 29, 33, 34, 36, 40, 43, 46, 47, 49, 50, 51, 52, 53, 63) having measuring element (3, 1 1, 17, 23, 25,

32, 37, 38, 42, 45, 48, 57, 62), which is frictionally fitted into the material recess (2, 16, 20), characterized in that the sensor (4, 13, 18, 22, 27, 28 , 29, 33, 34, 36, 40, 43, 46, 47, 49, 50, 51, 52, 53, 63) on or on the measuring element (3, 11, 17, 23, 25, 32, 37) , 38, 42, 45, 48, 57, 62), that the measuring direction of the sensor (4, 13, 18, 22, 27, 28, 29,

33, 34, 36, 40, 43, 46, 47, 49, 50, 51, 52, 53, 63) substantially coincides with the line of action of the pressure angle.

2. Component according to claim 1, characterized in that on or in the measuring element (48) a total of four a measuring bridge forming sensors

(51) are arranged.

3. Component according to claim 1 or 2, characterized in that the at least one sensor (13) on or on a chamfered surface (12) of the measuring element (1 1) is arranged, which is aligned with the line of action of the pressure angle.

4. Component according to one of the preceding claims, characterized in that the measuring element (3, 1 1, 17, 23, 25, 32, 37, 38, 42, 45, 48, 57, 62) axially or radially or obliquely to the axial - And radial direction in the component (1, 10, 14, 19) is arranged.

5. Component according to one of the preceding claims, characterized in that the sensor (4, 13, 18, 22, 27, 28, 29, 33, 34, 36, 40, 43, 46, 47, 49, 50, 51, 52, 53, 63) is arranged on or on the measuring element (3, 11, 17, 23, 25, 32, 37, 38, 42, 45, 48, 57, 62) in such a way that the measuring direction of the sensor (4 , 13, 18, 22, 27, 28, 29, 33, 34, 36, 40, 43, 46, 47, 49, 50, 51, 52, 53, 63) substantially coincides with the line of action of the nominal pressure angle or the operating pressure angle.

6. Component according to one of the preceding claims, characterized in that the measuring element (25, 32) has a plurality of parallel planes (30,

31) arranged sensors (28, 29).

7. Component according to claim 6, characterized in that a parallel plane (30, 31) has a plurality of mutually rotated or orthogonally arranged sensors.

8. Component according to one of the preceding claims, characterized in that the measuring element (37, 38, 42, 48) has a plane (35, 39, 44) on which a plurality of sensors (36, 43, 51) are arranged side by side.

9. Component according to one of the preceding claims, characterized in that a measuring element (37, 52) with a plane parallel to the axial direction (35, 54) with orthogonally depressed sensors (36, 53) is provided, wherein the measuring element (37, 52 ) is formed in two parts and a first plane having the parallel plane (35, 54) and a second, complementary thereto part, wherein the sensors (36, 53) are arranged between the two parts.

10. Component according to one of the preceding claims, characterized in that it comprises means for tracking a measuring plane of the sensor

(63), wherein the means is adapted to move the sensor (63) in the position of the maximum measurement signal.