Measuring roller for measuring a strip tension, apparatus, and method

Abstract

The invention relates to a measuring roller for determining a property of a strip-type material, in particular a metal strip, that is guided over the measuring roller, said measuring roller comprising: · a measuring roller body which has a peripheral surface and extends along an axis of rotation, · a recess in the measuring roller body, which recess is positioned at a distance from the peripheral surface or leads from the peripheral surface into the interior of the measuring roller body, · a first force sensor which is located in the recess, · and a second force sensor, the second force sensor either being located in the recess or a further recess being provided in the measuring roller body which is positioned at a distance from the peripheral surface or leads from the peripheral surface into the interior of the measuring roller body, and the second force sensor being located in the further recess, the first and second force sensors measuring a force which acts in a radial direction of the measuring roller body. · The measuring roller also has a third force sensor, wherein the third force sensor · is either located in the recess · or is located in the further recess · or a separate recess for the third force sensor is provided in the measuring roller body, which separate recess is positioned at a distance from the peripheral surface or leads from the peripheral surface into the interior of the measuring roller body, and the third force sensor is located in said recess provided for said third force sensor, wherein the third force sensor measures a force which acts parallel to the axis of rotation of the measuring roller body.

Description

[0001] "Measuring roller for measuring a strip tension, device and method"

[0002] The invention relates to a measuring roller for determining a property of a strip-shaped material guided over the measuring roller. The invention also relates to a method for determining a property of a strip-shaped material. The invention also relates to a method for producing a measuring roller for determining a property of a strip-shaped material guided over the measuring roller.

[0003] From WO 2020 / 120328 A1 a method is known in which an evaluation unit generates information dependent on a sensor signal of a first force sensor of a measuring roller and a sensor signal of a second force sensor of the measuring roller, which information corresponds to the strip tension with which a strip-shaped material is guided over the measuring roller or is directly proportional to the strip tension.The method described provides that the strip-shaped material is guided over a measuring roller for determining a property of a strip-shaped material guided over the measuring roller, wherein the measuring roller is designed with a measuring roller body having a circumferential surface, at least one recess in the measuring roller body, which is arranged at a distance from the circumferential surface or leads from the circumferential surface into the interior of the measuring roller body and with a first force sensor, which is arranged in the recess, and a second force sensor, which is arranged in the recess or a further recess adjacent to the recess.

[0004] The first force sensor has a sensor surface and the first force sensor can generate a sensor signal when the position of the sensor surface of the first force sensor changes. The second force sensor has a sensor surface and the second force sensor can generate a sensor signal when the position of the sensor surface of the second force sensor changes. The measuring roller is designed such that either the first force sensor is arranged in the recess next to the second force sensor and the sensor surface of the first force sensor is directly adjacent to the sensor surface of the second force sensor or the first force sensor is arranged so close to the second force sensor that the angle between an end boundary line running in the radial direction of the measuring roller, which intersects the point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor, and a line that

[0005] • runs in the plane containing the end limit line and the line connecting the point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor with the point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor, and

[0006] • intersects the end boundary line at the intersection point of the end boundary line with the peripheral surface, and

[0007] • the angle that intersects the point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor is less than 65°.

[0008] In the method described, the strip-shaped material is guided over the measuring roller in such a way that it partially wraps around the measuring roller. The method provides that the sensor signal generated by the first force sensor due to the change in the position of the sensor surface of the first force sensor, which results from the compressive force resulting from the wrapping, is fed to an evaluation unit and the sensor signal generated by the second force sensor due to the change in the position of the sensor surface of the second force sensor, which results from the compressive force resulting from the wrapping, is fed to an evaluation unit and the evaluation unit generates information dependent on the sensor signal of the first force sensor and the sensor signal of the second force sensor.

[0009] When processing strip-shaped material, the strip tension acting on it is of interest. Strip tension refers to a tensile force acting on the strip-shaped material or the tensile stress prevailing in the strip. Within a device, the strip tension acts as a tensile force, for example, in the longitudinal direction of the strip-shaped material. A deflection roller, at which the material is deflected, is subjected to compressive force by the strip tension.

[0010] For conventional rollers, the support forces of the rollers can be measured to measure the belt tension. Special force measuring devices are usually installed under the roller supports or deflection rollers.

[0011] The problem with the method known from WO 2020 / 120328 A1 is that the strip tension is only measured once per revolution of the measuring roller.

[0012] Against this background, the object of the invention was to create a measuring roller for determining a property of a strip-shaped material guided over the measuring roller, a method for determining a property of a strip-shaped material and a method for producing a measuring roller for determining a property of a strip-shaped material guided over the measuring roller, which allow the strip tension to be determined more frequently than once per revolution by means of the measuring roller.

[0013] This object is achieved by the measuring roller according to claim 1, by the method according to claim 6 and by the method according to claim 7. Advantageous embodiments are set out in the subclaims and the description below.

[0014] The invention is based on the basic idea of ​​providing a further force sensor, namely the third force sensor, within a measuring roller which is equipped with force sensors which are usually used to measure the flatness of the strip-shaped material, namely the first force sensor and the second force sensor. This third force sensor is intended to detect a force acting on it axially instead of a force acting on it radially. The inventors have recognized that the deflection of the measuring roller body can be determined using a force sensor which is arranged within the measuring roller body and can measure a force acting on it axially. The inventors have also recognized that the deflection of the measuring roller body depends on the strip tension acting on the strip-shaped material guided over the measuring roller.By adding the third force sensor, the invention therefore creates the possibility of measuring, in addition to the property of the strip-shaped material guided over the measuring roller, which is determined by means of the first force sensor and the second force sensor (often the flatness), a further property of the strip-shaped material guided over the measuring roller, namely the strip tension acting on the strip-shaped material.

[0015] By adding the third force sensor, which measures forces acting in a different direction, namely the axial direction, compared to the radial forces acting on the first force sensor and the second force sensor, the invention creates a decoupling of the measuring tasks. In the method known from W02020 / 120328 A1, the existing force sensors, which in W02020 / 120328 A1 can also be used to measure the flatness of the strip-shaped material, are assigned the additional task of measuring the strip tension. This advantageously means that in W02020 / 120328 A1, the already existing force sensors can also be used for a second measuring task. Thus, the effort required for W02020 / 120328 A1 is relatively lower.With W02020 / 120328 A1, no additional force sensors need to be provided for the second measuring task (e.g., measuring strip tension), which means that relatively fewer parts are required. However, the multiple use of existing components that results in this advantage with W02020 / 120328 A1 also means that the setup for the second measuring task, e.g., measuring strip tension, cannot be individually optimized. To perform the second measuring task, the setup must be accepted as it is provided for the first measuring task. This leads, among other things, to the problem described above that with the method according to W02020 / 120328 A1, the strip tension is only ever measured once per revolution of the measuring roller.

[0016] The invention is based on the fundamental idea that by evaluating the sensor signal of the third force sensor, the strip tension acting on the strip-shaped material guided over the measuring roller can be measured at any time. The measuring roller rotates around the rotational axis (hereinafter sometimes referred to as the longitudinal axis) while the strip-shaped material is guided over it. According to the findings of the invention, the strip tension acting on the strip-shaped material guided over the measuring roller can be determined at virtually any angular position of the measuring roller during this rotation by evaluating the sensor signal of the third force sensor.

[0017] The measuring roller according to the invention is suitable for determining one property of a strip-shaped material, in particular of metal strip, guided over the measuring roller. The measuring roller is particularly preferably suitable for determining two properties of the strip-shaped material, in particular of metal strip, guided over the measuring roller. In a preferred embodiment, the measuring roller is suitable for determining the flatness of the strip-shaped material, in particular of metal strip, guided over the measuring roller. An inventive use of the measuring roller according to the invention therefore provides for the use of the measuring roller for determining the flatness of a strip-shaped material, in particular of metal strip, guided over the measuring roller. Additionally or alternatively, the measuring roller is suitable for determining the strip tension acting on a strip-shaped material, in particular of metal strip, guided over the measuring roller.A use according to the invention therefore provides that the measuring roller according to the invention is used to determine the strip tension acting on a strip-shaped material, in particular a metal strip, guided over the measuring roller. In a particularly preferred use according to the invention, the measuring roller according to the invention is used to determine the flatness of a strip-shaped material, in particular a metal strip, guided over the measuring roller and to determine the strip tension acting on this strip-shaped material.

[0018] DESCRIPTION OF MEASURING ROLLER (BASIC CONSTRUCTION):

[0019] The measuring roller according to the invention has a measuring roller body. The measuring roller body preferably has a closed circumferential surface. In a preferred embodiment, the measuring roller body is a solid roller that extends along a longitudinal axis (axis of rotation). A solid roller is understood to be a measuring roller body that is in one piece and whose shape was either produced using a primary forming process, for example casting, and / or whose geometric shape is produced from a one-piece semi-finished product by separating processes, in particular by machining, in particular by turning, drilling, milling, or grinding. Additionally or alternatively, the solid roller can also be produced entirely or in parts (in particular in layers) by applying layers, as described in particular in WO 2020 / 174001 A1.

[0020] In a preferred embodiment, in a measuring roller body designed as a solid roller, the measuring roller pins arranged on the front side of the measuring roller for rotatably supporting the measuring roller, for example in ball bearings, are also part of the one-piece body. However, designs such as those shown in Fig. 2 of DE 20 2014 006 820 U1 are also conceivable, in which the main part of the measuring roller body is designed as a cylindrical solid roller with covers arranged on the front side on which the measuring roller pins are formed. Furthermore, the measuring roller body according to the invention can be designed, for example, like the measuring roller body shown in Fig. 3 of DE 20 2014 006 820 U1, in which the measuring roller body is designed with molded-on pins and a casing tube is pushed over the measuring roller body. In a particularly preferred embodiment, however, the measuring roller does not have a casing tube, but is designed as a solid roller.

[0021] The measuring roller body of the measuring roller according to the invention preferably has a closed circumferential surface. This can be achieved, for example, by designing the measuring roller body as a solid roller and forming all recesses provided in the measuring roller body such that no recess leads to or opens into the circumferential surface. In such an embodiment, the recesses are particularly preferably guided axially and have an opening on an end face of the measuring roller body, or transverse channels are provided within the measuring roller body, which lead radially from the recess further into the interior of the measuring roller body, for example, to a collecting channel in the center of the measuring roller body.A closed circumferential surface of the measuring roller body can also be achieved in that, in embodiments in which the respective recess has a recess leading in the direction of the circumferential surface, this recess is closed by a closure element. Such a closure element can be a casing tube that completely surrounds a base body of the measuring roller body, as shown, for example, in Figs. 3 and 4 of DE 102014 012 426 A1. However, the closure element can also be designed in the manner of the cover shown in DE 19747655 A1. In a preferred embodiment, however, the measuring roller does not have a casing tube, but is designed as a solid roller, either as one in which no recess leads to the circumferential surface, or as one in which the respective recess is a recess leading in the direction of the circumferential surface, but which is closed by a closure element, such as a cover.In addition, coatings are conceivable, for example on the circumferential surface of a solid roller or the circumferential surface of a casing pipe, for example to reduce friction or to protect the strip-shaped material to be guided over the measuring roller.

[0022] At least one recess is provided in the measuring roller body of the measuring roller according to the invention. It has been shown that the advantages of the invention can be achieved with just a single recess in the measuring roller body. Thus, for flatness measurements, it is conceivable to provide information about the flatness of the strip-shaped material guided over the measuring roller once per revolution of the measuring roller.

[0023] In a preferred embodiment, the measuring roller body has a plurality of recesses. In a preferred embodiment, the recesses are designed at the same radial distance from the longitudinal axis of the measuring roller body. In a preferred embodiment, all recesses are arranged equidistant from one another in the circumferential direction. However, embodiments are also conceivable in which a first group of recesses is provided, which are particularly preferably arranged at the same radial distance from the longitudinal axis and equidistant in the circumferential direction, and in which, in addition to this first group of recesses, at least one further recess is provided, which is either designed differently than the recesses in terms of its radial distance from the longitudinal axis and / or does not have the same distance in the circumferential direction from the other recesses as the other recesses have from one another.For example, it is conceivable to design a measuring roller with regard to flatness measurement in the same way as a prior art measuring roller, for example like the solid roller known from DE 102 07 501 or the measuring rollers known from DE 10 2014 012 426 A1, but then to provide these prior art measuring rollers with a further recess outside the grid for the equipment according to the invention, with which, for example, a different measurement is carried out, namely the measurement to be carried out with the third force sensor. Preferably, the recesses mentioned in this paragraph are those that run in the axial direction of the measuring roller body. Embodiments are also conceivable in which the measuring roller has a single recess and all force sensors of the measuring roller are arranged in a single recess, for example in a single axially running recess.

[0024] In a preferred embodiment, the measuring roller body has a closed circumferential surface and is terminated at each end by a front end. In a preferred embodiment, the front ends are arranged at an angle of 90° to the circumferential surface.

[0025] In a preferred embodiment, the measuring roller has bearing journals. In a preferred embodiment, in embodiments of the measuring roller with end faces, the bearing journals are formed on the end faces.

[0026] In a preferred embodiment, the measuring roller body is cylindrical.

[0027] ARRANGEMENT OF FIRST and SECOND FORCE SENSORS:

[0028] According to the invention, the measuring roller has a first force sensor arranged in a recess. In a preferred embodiment, the recess is arranged at a distance from the peripheral surface, wherein the recess does not open toward the peripheral surface, or no further recess, for example, a bore, leading from the recess leads to the peripheral surface. In an alternative, likewise preferred embodiment, the recess leads from the peripheral surface into the interior of the measuring roller body, but is closed by a closure element.

[0029] According to the invention, the measuring roller has a second force sensor which is arranged in a recess. In a preferred embodiment, the first force sensor and the second force sensor are arranged in one recess. In a preferred, alternative embodiment, the second force sensor is arranged in a further recess, i.e. not in the recess in which the first force sensor is arranged. In a preferred embodiment, the further recess is arranged at a distance from the circumferential surface, wherein the further recess does not open towards the circumferential surface, or no recess leading from the further recess, for example no bore, leads to the circumferential surface. In an alternative, likewise preferred embodiment, the further recess leads from the circumferential surface into the interior of the measuring roller body, but is closed by a closure element.

[0030] In a preferred embodiment, a recess in the measuring roller body extends in a direction parallel to the longitudinal axis of the measuring roller body. If, according to a preferred embodiment, several recesses are provided in the measuring roller body, it is preferred that all recesses in the measuring roller body each extend in a direction parallel to the longitudinal axis of the measuring roller body. In a preferred embodiment, the respective recess opens at least at one of its ends, preferably at both of its ends, onto an end face of the measuring roller body. A recess ending at an end face of a measuring roller body can be closed by an end cap, wherein this end cap only closes this recess. Embodiments are also conceivable in which the end face of the measuring roller body is completely closed by a cover, as shown, for example, in Figs. 1 and 2, or Fig. 4 of DE 10 2014 012 426 A1.

[0031] In a preferred embodiment, the recess, or if several recesses are provided, at least one recess is preferably elongated, wherein “elongated” is understood to mean that the recess is larger in a first direction (in the longitudinal direction of the recess) than in any direction perpendicular to this direction. In a preferred embodiment, the extension of the elongated recess in the longitudinal direction is twice or particularly preferably more than twice greater than in any direction perpendicular to this direction. In a preferred embodiment, the longitudinal direction of the recess encloses an angle with the longitudinal direction of the measuring roller body which is smaller than 75°, particularly preferably <45°, particularly preferably <30°, particularly preferably <10°, particularly preferably <5°.In a preferred embodiment, the longitudinal direction of the recess is not perpendicular to the longitudinal axis of the measuring roller body. If - as would be conceivable in one embodiment - the longitudinal axis of the recess and the longitudinal axis of the measuring roller body do not intersect, the aforementioned design rule applies to the projection of the longitudinal axis of the recess onto the plane containing the longitudinal axis of the measuring roller body. In these embodiments, the projection of the longitudinal axis of the recess onto a plane containing the longitudinal axis of the measuring roller body is therefore designed such that the projection of the longitudinal direction of the recess encloses an angle with the longitudinal direction of the measuring roller body that is smaller than 75°, particularly preferably <45°, particularly preferably <30°, particularly preferably <10°, particularly preferably <5°.In the preferred embodiments in which the recess extends parallel to the longitudinal axis of the measuring roller body, the longitudinal axis of the recess obviously does not intersect the longitudinal axis of the measuring roller body, just as a projection of the longitudinal axis onto a plane containing the longitudinal axis of the measuring roller body does not intersect the longitudinal axis of the measuring roller body. For example, DE 20 2007 001 066 U1 shows a measuring roller with elongated recesses.

[0032] In other preferred embodiments, at least one recess is not elongated but designed as a radially extending pocket, as shown, for example, in DE 19838457 A1. This recess can, for example, be used as a separate recess for the third force sensor.

[0033] In a preferred embodiment, the first force sensor and the second force sensor are arranged in a recess (if the measuring roller has only one recess: in the recess) of the measuring roller.

[0034] ARRANGEMENT OF THIRD FORCE SENSOR:

[0035] According to the invention, the measuring roller has a third force sensor.

[0036] The third force sensor can be arranged in the recess in which the first force sensor is also arranged. If, according to a preferred embodiment, the first force sensor and the second force sensor are arranged in a recess, then, according to a preferred embodiment, the third force sensor can also be provided in this one recess; the first force sensor, the second force sensor, and the third force sensor are arranged in a recess in this preferred embodiment. In a preferred embodiment of this embodiment, the recess is an elongated recess, which particularly preferably extends parallel to the longitudinal axis of the measuring roller body.

[0037] The third force sensor can be arranged in the recess in which the second force sensor is also arranged. If, according to a preferred embodiment, the first force sensor is arranged in one recess and the second force sensor is arranged in a further recess, then, according to a preferred embodiment, the third force sensor can be provided in the further recess; in this preferred embodiment, the second force sensor and the third force sensor are arranged in one recess, namely the further recess, while the first force sensor is arranged in a separate recess. In a preferred embodiment of this embodiment, the further recess is an elongated recess which, in particular, preferably extends parallel to the longitudinal axis of the measuring roller body.In an alternative embodiment, a separate recess is provided in the measuring roller body for the third force sensor, which is arranged at a distance from the circumferential surface or leads from the circumferential surface into the interior of the measuring roller body, wherein the third force sensor is arranged in this recess provided for it. In a preferred embodiment, the first force sensor and the second force sensor are arranged in one recess and the third force sensor is arranged in a separate recess provided for the third force sensor. In an alternative embodiment, the first force sensor is arranged in one recess, the second force sensor is arranged in a further recess and the third force sensor is arranged in a recess provided for it, which is not the recess in which the first force sensor is arranged and is not the further recess.

[0038] In embodiments in which the third force sensor is arranged in its own recess, according to a preferred embodiment, the recess provided specifically for the third force sensor is designed differently, in particular is aligned differently, than a recess in which the first force sensor is arranged. In a preferred embodiment, the recess in which the first force sensor is arranged is an elongated recess which particularly preferably extends parallel to the longitudinal axis of the measuring roller body, wherein the recess provided specifically for the third force sensor is not designed parallel to the longitudinal axis of the measuring roller body, but rather designed as radially extending pockets, as shown, for example, in DE 198 38 457 A1.

[0039] DESCRIPTION OF FORCE SENSORS:

[0040] The first force sensor has a sensor surface, wherein the force sensor can generate a sensor signal when the position of the sensor surface of the first force sensor changes. The second force sensor also has a sensor surface, wherein the second force sensor can generate a sensor signal when the position of the sensor surface of the second force sensor changes. The third force sensor also has a sensor surface, wherein the third force sensor can generate a sensor signal when the position of the sensor surface of the third force sensor changes. Force sensors are called force sensors because they are used to measure forces, particularly preferably compressive forces. In order to measure the force acting on them, the force sensors are designed such that they have a sensor surface and can generate a sensor signal when the position of the sensor surface changes.Force sensors usually have an associated reference system and react to changes in the position of the sensor surface in this reference system. Force sensors often have a housing. The reference system is then frequently the housing. In such an embodiment, the force sensor can, for example, determine whether the position of the sensor surface has changed relative to the housing. If the force sensor is designed as a piezoelectric force sensor, for example, it has a piezo quartz that can generate an electrical signal when the position of one of its surfaces changes relative to a reference surface, for example an opposite surface of the piezo quartz, if the piezo quartz is compressed, for example. In a force sensor designed as a strain gauge, a change in the position of the surface of the force sensor changes the length of the measuring wire orThe measuring grid formed by measuring wires is changed, usually stretched, but sometimes also compressed. In a force sensor designed as an optical force sensor, the optical properties of the force sensor, such as the refractive index or reflection properties, are changed by the change in the surface position.

[0041] The force sensors to be used according to the invention have a sensor surface whose change in position the force sensor observes to determine a force acting on it. Embodiments are conceivable in which the sensor surface is a surface of the element whose properties are changed to generate the sensor signal, for example a surface of the piezo quartz itself. However, intermediate pieces on which the sensor surface is formed are often provided in such force sensors. Such intermediate pieces are often rigid blocks in which a change in the position of one surface of the rigid block directly leads to a change in the position of the opposite surface due to the rigidity of the block. Such intermediate pieces can be used to design the sensor surface to protrude from other parts of the force sensor, in particular from a housing.By having a sensor surface that protrudes relative to other parts of the force sensor, measurement accuracy is increased because it creates a clearly defined surface upon which the environment can act. By having protruding sensor surfaces, measurement errors caused by force shunts can be prevented, for example. The force sensor according to the invention can, for example, be designed like the force sensor shown in DE 1 773 551 A1 and have a piezo element arranged in a housing and consisting of a multi-layer crystal arrangement, which is arranged between two force transmission disks. In such an embodiment, the sensor surface would be the outer surface of the upper force transmission disk in Fig. 1 of DE 1 773 551 A1 or the outer surface of the lower force transmission disk in Fig. 1 of DE 1 773 551 A1.

[0042] In a preferred embodiment, the sensor surface is flat. In a preferred embodiment, the surface normal of the flat sensor surface of the first force sensor points towards the circumferential surface. In a preferred embodiment, the surface normal of the sensor surface of the second force sensor is likewise flat and, in a preferred embodiment, likewise points towards the circumferential surface. In a preferred embodiment, the surface normal of the sensor surface of the first force sensor is parallel to the surface normal of the sensor surface of the second force sensor. In a preferred embodiment, a radial direction of the measuring roller body is a surface normal of the sensor surface of the first and / or the second force sensor. In a preferred embodiment, the surface normal of the sensor surface of the third force sensor is likewise flat and, in a preferred embodiment, points in a direction parallel to the axis of rotation.

[0043] In a preferred embodiment, the surface normal of a flat sensor surface of the first force sensor and / or the second force sensor at the point on the sensor surface at which the sensor surface is intersected by a radial of the measuring roller body is at an angle to this radial of the measuring roller body which is less than 45°, particularly preferably less than 20°, particularly preferably less than 10°, particularly preferably less than 5°.

[0044] In a preferred embodiment, the surface normal of a flat sensor surface of the third force sensor is at a point on the sensor surface at which the sensor surface is intersected by a line running parallel to the axis of rotation of the measuring roller body, at an angle to this line which is less than 45°, particularly preferably less than 20°, particularly preferably less than 10°, particularly preferably less than 5°.

[0045] In a preferred embodiment, the sensor surface of a force sensor used in the measuring roller according to the invention, in particular of the first force sensor and / or the second force sensor and / or the third force sensor, is a flat surface.

[0046] In a preferred embodiment, the sensor surface is ring-shaped, particularly circular. Likewise preferred are embodiments in which the sensor surface is circular or elliptical. Rectangular, square, or polygonal sensor surfaces are also conceivable. In a preferred embodiment, the sensor surface is flat.

[0047] In a preferred embodiment, the sensor surface is a surface which is highlighted from other elements of the force sensor and which is in contact with a boundary surface of the recess or which is in contact with a closure element which closes the recess towards the peripheral surface.

[0048] In a preferred embodiment, at least two force sensors used in the measuring roller according to the invention, particularly preferably the majority of the force sensors used in the measuring roller according to the invention, particularly preferably all force sensors used in the measuring roller according to the invention, are of the same type, thus of the same type and in particular of the same series, and particularly preferably of identical construction. The third force sensor can be designed as a strain sensor, in particular as a surface strain sensor. For example, the type 9232A sensor from Kistler AG (https: / / www.kistler.com / de / produkt / type-9232a / as available on May 27, 2022) can be used for the third force sensor.

[0049] The first force sensor and / or the second force sensor and / or the third force sensor can be fixed or clamped, for example, wedged, in the recesses in which they are arranged. These preloads are intentional and can be easily compensated for by measurement. The preload can be set to a predetermined value. For example, force sensors with plane-parallel surfaces can be arranged between wedge-shaped holding pieces, such as clamping wedges, which are moved against each other until the force sensor is firmly clamped between the holding pieces.

[0050] In a preferred embodiment, the respective force sensor is arranged on a housing or a holder, which simplifies handling during production. The housing can be arranged in a recess in the measuring roller. It can be provided that the force sensor of the first type is preloaded in the housing and / or with the housing. According to the invention, the term “housing” also covers holders that do not have the closed design of a conventional housing. A housing according to the invention can be designed in particular as described in DE 102006003792 A1, the disclosure content of which is explicitly incorporated herein by reference, wherein the housing or the holder has an inner sleeve having an outer circumferential cone, in which a force sensor is arranged, and an outer sleeve having an inner circumferential cone that can be engaged with the inner sleeve or clamped thereto.

[0051] According to the type of DE 10 2006 003 792 A1, the first force sensor and the second force sensor can be arranged in an axially extending recess and the third force sensor in a radially extending recess.

[0052] According to the invention, the sensor surface of the first force sensor is arranged such that its position can be changed by a force acting on it in a radial direction of the measuring roller body. In a preferred embodiment, the action of a force on the sensor surface of the first force sensor occurs in that a force acting on the measuring roller body moves a surface of a component of the measuring roller body adjacent to the first force sensor, which is in contact with the sensor surface or is brought into contact with the sensor surface by the action of the force acting on the measuring roller body, further in the direction of the first force sensor. The attempt to move the surface of the adjacent component in contact with the sensor surface further in the direction of the first force sensor is successful above a certain force level in that the sensor surface of the first force sensor changes its position.The specific force level at which this effect occurs is a measure of the sensitivity of the sensor. If the force that seeks to move the surface of the adjacent component further towards the first force sensor is so small that the sensor surface does not yield (does not change its position), then this force is below the sensitivity of the sensor. Therefore, the teaching provided by the invention of arranging the sensor surface of the first force sensor such that its position can be changed by a force acting on it in a radial direction of the measuring roller body can be implemented by providing a component adjacent to the first force sensor in the radial direction of the measuring roller body, which component has a surface that is either already in contact with the sensor surface in the initial state, or that is brought into contact with the sensor surface when a force acts on the measuring roller body.If the first force sensor is arranged in an axial bore, for example, this surface can be provided, for example, by a portion of the surfaces surrounding the axial bore arranged radially above or below the first force sensor. If the first force sensor is arranged, for example, in a radial bore that is closed with a closure element, the surface can be formed, for example, by the underside of the closure element.

[0053] According to the invention, the sensor surface of the second force sensor is arranged such that its position can be changed by a force acting on it in a radial direction of the measuring roller body. In a preferred embodiment, the action of a force on the sensor surface of the second force sensor occurs in that a force acting on the measuring roller body moves a surface of a component of the measuring roller body adjacent to the second force sensor, which is in contact with the sensor surface or is brought into contact with the sensor surface by the action of the force acting on the measuring roller body, further in the direction of the second force sensor. The attempt to move the surface of the adjacent component in contact with the sensor surface further in the direction of the second force sensor is successful above a certain force level in that the sensor surface of the second force sensor changes its position.The specific force level at which this effect occurs is a measure of the sensitivity of the sensor. If the force that seeks to move the surface of the adjacent component further towards the second force sensor is so small that the sensor surface does not yield (does not change its position), then this force is below the sensitivity of the sensor. Therefore, the teaching provided by the invention of arranging the sensor surface of the second force sensor such that its position can be changed by a force acting on it in a radial direction of the measuring roller body can be implemented by providing a component adjacent to the second force sensor in the radial direction of the measuring roller body, which component has a surface that is either already in contact with the sensor surface in the initial state, or that is brought into contact with the sensor surface when a force acts on the measuring roller body.If the second force sensor is arranged in an axial bore, for example, this surface can be provided, for example, by a portion of the surfaces surrounding the axial bore arranged radially above or below the second force sensor. If the second force sensor is arranged, for example, in a radial bore that is closed with a closure element, the surface can be formed, for example, by the underside of the closure element.

[0054] According to the invention, the sensor surface of the third force sensor is arranged such that its position can be changed by a force acting on it parallel to the axis of rotation of the measuring roller body. In a preferred embodiment, a force acts on the sensor surface of the third force sensor in that a force acting on the measuring roller body moves a surface of a component of the measuring roller body adjacent to the third force sensor, which is in contact with the sensor surface or is brought into contact with the sensor surface by the action of the force acting on the measuring roller body, further in the direction of the third force sensor. The attempt to move the surface of the adjacent component in contact with the sensor surface further in the direction of the third force sensor is successful above a certain force level in that the sensor surface of the third force sensor changes its position.The specific force level at which this effect occurs is a measure of the sensor's sensitivity. If the force that tends to move the surface of the adjacent component further toward the third force sensor is so small that the sensor surface does not yield (does not change its position), then this force is below the sensor's sensitivity. Therefore, the teaching provided by the invention of arranging the sensor surface of the third force sensor such that its position can be changed by a force acting on it parallel to the axis of rotation of the measuring roller body can be realized by providing a component adjacent to the third force sensor in a direction parallel to the axis of rotation of the measuring roller body, which component has a surface that is either already in contact with the sensor surface in its initial state, or that is brought into contact with the sensor surface when a force acts on the measuring roller body.If, for example, the third force sensor is arranged in an axial bore and is intended to measure a force that results in an expansion of a portion of the surface surrounding the axial bore, this surface can be provided, for example, by a portion of the surfaces surrounding the axial bore arranged radially above or below the third force sensor, with the force being transmitted by friction. If, for example, the first force sensor is arranged in a radial bore, this surface can be provided, for example, by a portion of the surfaces surrounding the radial bore arranged axially next to the third force sensor.

[0055] The invention makes use of the knowledge that the measuring roller body bends when it

[0056] • on the one hand, is radially supported at the end, for example by supporting the bearing journals of the measuring roller in stands,

[0057] • and on the other hand, a band-shaped material subjected to band tension is guided over the measuring roller with a wrap angle.

[0058] In the course of describing the invention, it is assumed, on the one hand, that the change in shape of the measuring roller body resulting from the deflection, for example the fact that the axis of rotation is no longer a completely straight axis when the measuring roller body is bent, but is slightly curved, is so small that a person skilled in the art would still describe the spatial relationships of bodies as "radial" or "parallel to the axis of rotation." Furthermore, the spatial relationships chosen in the course of describing the invention, such as "radial" or "radial direction" or "axial" or "parallel to the axis of rotation," apply in any case when the measuring roller is unloaded, i.e. when the measuring roller is considered as such and without it having already been deflected by a material guided over the measuring roller.

[0059] In a preferred embodiment, the first force sensor and / or the second force sensor and / or the third force sensor are each a piezoelectric force sensor, a strain gauge or an optical force sensor. In a preferred embodiment, at least the first force sensor and the second force sensor are of the same type. In a preferred embodiment, the first force sensor and the second force sensor and the third force sensor are of the same type, preferably a piezoelectric force sensor. In a preferred embodiment, the first force sensor and the second force sensor are of the same type, but the third force sensor is of a different type. In a preferred embodiment, the first force sensor and the second force sensor are piezoelectric force sensors, but the third force sensor is a strain gauge.

[0060] In a preferred embodiment, the third force sensor is arranged closer to the circumferential surface than to the axis of rotation. It is to be expected that a change in shape of the measuring roller body resulting from bending will be more pronounced in regions of the measuring roller body that are arranged closer to the circumferential surface than to the axis of rotation than in regions that are arranged closer to the axis of rotation than to the circumferential surface. Since, in a preferred embodiment, the magnitude of the force to be determined by the third force sensor depends on the magnitude of the change in shape of the measuring roller body in the region in which the third force sensor is arranged, it is advantageous if the third force sensor is arranged in the region in which the change in shape is particularly large.

[0061] In a preferred embodiment, the measuring roller body has two opposite ends and a center located centrally between these two ends, wherein the third force sensor is preferably arranged in the center. In a preferred embodiment, a force sensor arranged between the center and one end is arranged at least closer to the center than to the end. It is to be expected that a change in shape of the measuring roller body resulting from bending will be more pronounced in regions of the measuring roller body that are arranged closer to the center than to one end of the measuring roller body than in regions that are arranged closer to one end than to the center.Since, in a preferred embodiment, the magnitude of the force to be determined by the third force sensor depends on the magnitude of the change in shape of the measuring roller body in the region in which the third force sensor is arranged, it is advantageous if the third force sensor is arranged in the region in which the change in shape is particularly large.

[0062] In a preferred embodiment, a fourth force sensor is provided, wherein the fourth force sensor

[0063] • is either arranged in the recess

[0064] • or is arranged in the further recess

[0065] • or is arranged in the recess provided for the third force sensor

[0066] • or a separate recess is provided in the measuring roller body for the fourth force sensor, which is arranged at a distance from the circumferential surface or leads from the circumferential surface into the interior of the measuring roller body, and the fourth force sensor is arranged in this recess provided for it, wherein the fourth force sensor has a sensor surface and the fourth force sensor can generate a sensor signal when the position of the sensor surface of the fourth force sensor changes, wherein the sensor surface of the fourth force sensor is arranged such that its position can be changed by a force acting on it parallel to the axis of rotation of the measuring roller body.

[0067] The fourth force sensor is particularly preferably used to confirm the measurement result of the third force sensor. In a preferred embodiment, the third force sensor and the fourth force sensor are arranged in a plane perpendicular to the rotation axis. In this preferred embodiment, the third force sensor and the fourth force sensor are thus arranged "at the same height" between the ends of the measuring roller body.

[0068] In a preferred embodiment, in addition to the first force sensor and the second force sensor, the measuring roller body has a plurality of, preferably more than 3, further, preferably more than 5 further force sensors, of which the respective force sensor is arranged in a recess, preferably in the recess of the first force sensor or alternatively in a separate recess, wherein the recess in which the respective force sensor is arranged is arranged at a distance from the circumferential surface or leads from the circumferential surface into the interior of the measuring roller body, wherein the respective force sensor has a sensor surface and the respective force sensor can generate a sensor signal when the position of the sensor surface of the respective force sensor changes, wherein the sensor surface of the respective force sensor is arranged such that its position can be changed by a force acting on it in a radial direction of the measuring roller body.The greater the number of force sensors whose sensor surface position can be changed by a force acting on them in a radial direction of the measuring roller body, the more accurate the resolution of determining the flatness of the strip-shaped material guided over the measuring roller can be. With regard to the arrangement of the force sensors, whose sensor surface position can be changed by a force acting on them in a radial direction of the measuring roller body, the measuring roller according to the invention can be designed as described in WO 2020 / 120329 A1. According to the invention, a measuring roller equipped in this way is supplemented by at least the "third force sensor" in order to use it, for example, to measure the strip tension of the strip-shaped material guided over the measuring roller.

[0069] The method according to the invention for determining a property of a strip-shaped material provides that the strip-shaped material is guided over a measuring roller according to the invention in such a way that the measuring roller bends.

[0070] In a preferred embodiment, the strip-shaped material is guided over the measuring roller according to the invention at a wrap angle. In a preferred embodiment, the wrap angle is between 0.5° and 90°, particularly preferably between 3° and 45°, and especially preferably between 5° and 30°.

[0071] In a preferred embodiment, an evaluation unit is provided which determines the strip tension acting on the strip-shaped material from the sensor signal of the third force sensor. The method according to the invention for producing a measuring roller according to the invention provides that the measuring roller has at least one layer and that the layer is

[0072] • Printing using a 3D printer,

[0073] • Laser beam melting,

[0074] • Electron beam melting,

[0075] • Laser powder deposition welding

[0076] • thermal spraying

[0077] • Build-up welding

[0078] • Contract soldering

[0079] • a wire laser deposition welding,

[0080] • a powder bed process, particularly preferably the so-called “Selective Laser Sintering” (SLS) or the so-called “Selective Laser Melting” (SLM),

[0081] • Laser Metal Deposition (LMD),

[0082] • Extremely high-speed laser cladding (EHLA) and / or

[0083] • Arc welding with wire feed. In a preferred embodiment, the measuring roller according to the invention is manufactured according to the method described in WO 2020 / 174001.

[0084] The invention relates to a measuring roller which can be used in the treatment, e.g. rolling, hardening, forming, coating, separating, punching, etc., in particular in an at least cyclically continuous process, of strip-shaped or two-dimensionally elongated material, e.g. made of / with metal, e.g. iron, steel, aluminum, copper, magnesium, titanium and / or zinc, and / or made of / with plastic and / or paper, and with which a strip tension on or the material can be measured.

[0085] The invention is explained in more detail below with reference to exemplary embodiments illustrated in the drawings. In the drawings:

[0086] Fig. 1 shows the side view of a first embodiment of a measuring roller, partly in section;

[0087] Fig. 2 a measuring roller with cable ducts in perspective view with the cover removed;

[0088] Fig. 3 shows a section of a front view of the measuring roller according to Fig. 2;

[0089] Fig. 4 is a sectional detailed view of the force sensors arranged in a bore; a plan view of the arrangement of the force sensors according to Fig. 4; Fig. 6 is a cross-section through a holder with a force sensor in the installed situation in a partially illustrated measuring roller in a sectional side view according to section line BB in Fig. 7; the elements of Fig. 6 in a view along section line AA in Fig.

[0090] 6; Fig. 8 shows the elements of Figs. 6 and 7 in a view along the section line CC of Fig. 7; a schematic representation of the forces acting on a measuring roller; Fig. 10 shows a schematic representation of a measuring roller according to the invention, which is bent by the radial forces which the strip-shaped material under strip tension introduces into the measuring roller; the schematic representation of Fig. 10 with representation of the

[0091] compressive and tensile stresses acting on the measuring roller body; a schematic side view of the measuring roller according to the invention for

[0092] Representation of the factors used in the calculation of the strip tension; Fig. 13 is a further schematic side view of the measuring roller according to the invention to illustrate the factors used in the calculation of the strip tension for an exemplary measuring situation; a schematic representation of a setup for determining the

[0093] Proportionality factor k; Fig. 15 is a graph illustrating the forces acting on the measuring roller; Fig. 16 is a graph showing the forces acting on the measuring roller and the resulting force measured by the sensor.

[0094] The measuring roller 1 according to the invention with a pin 2 has a measuring roller body 1a designed as a solid roller. A recess 3 designed as a bore parallel to the longitudinal axis A (rotational axis A) of the measuring roller body 1a is provided in the measuring roller body 1a, from which a transverse channel 4 branches off near its front side and leads to a central cable channel 5. The recess 3 is closed at the front side with a cover 6 or individually with covers and contains a first force sensor 7a, a second force sensor 7b arranged next to the first force sensor 7a, and further force sensors 7c, 7d arranged next to the second force sensor 7b, from each of which a cable 8 (shown as only one cable for the sake of simplicity) is guided outwards through the bore 3, the transverse channel 4, and the central channel 5.

[0095] The measuring roller 1, shown schematically in perspective in Fig. 2 and Fig. 3 with the cover 6 removed, has cable ducts 10, 11 lying opposite one another parallel to each bore 3 for cables led outwards via the transverse duct 4 and the central duct 5. While in the embodiment according to Fig. 2 and 3 a bore 3 is provided in which the force sensors 7a, 7b, 7c, 7d (not shown in Fig. 2 and 3) are arranged, embodiments as shown in Fig. 1 are also possible, in which a roller body 1a designed as a solid roller is designed with a groove on its outer circumference which forms the recess for the force sensors 7a, 7b, 7c, 7d, and is covered with a casing tube 1b closing the groove.

[0096] The embodiments of the measuring roller 1 according to the invention shown in the figures have a measuring roller body 1a extending along a rotation axis A with a circumferential surface 20. In the embodiment of Fig. 1, the circumferential surface 20 is the outer surface of the casing tube 1b, in the embodiment of Figs. 2 and 3, the circumferential surface 20 is the outer surface of the solid roller.

[0097] In both embodiments of Fig. 1 and Figs. 2 and 3, the measuring roller body 1a has a recess 3 (once designed as a bore (Figs. 2 and 3) and once as a groove closed by the casing tube 1b). The recess 3 is arranged at a distance from the circumferential surface (Figs. 1 to 3). A first force sensor 7a is arranged in the recess, wherein the first force sensor 7a has a sensor surface and the first force sensor 7a can generate a sensor signal when the position of the sensor surface of the first force sensor 7a changes, wherein the sensor surface of the first force sensor 7a is arranged such that its position can be changed by a force acting on it in a radial direction of the measuring roller body 1b. Furthermore, a second force sensor 7b is provided. In both embodiments of Fig. 1 and Figs. 2 and 3, the second force sensor 7b is arranged in the recess 3 in which the first force sensor 7a is also arranged.It would also be conceivable to provide a further recess in the measuring roller body 1a, which is arranged at a distance from the circumferential surface 20 or leads from the circumferential surface 20 into the interior of the measuring roller body 1a, and to arrange the second force sensor 7b in the further recess. The second force sensor 7b has a sensor surface. The second force sensor 7b can generate a sensor signal upon a change in the position of the sensor surface of the second force sensor 7b, wherein the sensor surface of the second force sensor 7b is arranged such that its position can be changed by a force acting on it in a radial direction of the measuring roller body 1a.

[0098] The measuring roller 1 has a third force sensor 17. This is arranged in a bore 13, which is radially formed in Fig. 1 and is also closed by the casing tube 1b. It would also be conceivable to arrange the third force sensor—similar to the force sensor 7c or 7d—in the bore 3 of the embodiment according to Fig. 1 and to design the third force sensor as a strain gauge that measures the strain of the wall delimiting the bore 3 in the embodiment according to Fig. 1.

[0099] The third force sensor 17 has a sensor surface. The third force sensor 17 can generate a sensor signal upon a change in the position of the sensor surface of the third force sensor 17. The sensor surface of the third force sensor 17 is arranged such that its position can be changed by a force acting on it parallel to the rotational axis A of the measuring roller body 1a.

[0100] Fig. 4 shows the arrangement of a first force sensor 107a and a second force sensor 107b in a bore 103 of a measuring roller body 1a of a measuring roller, which is designed as a solid roller with an axial bore 103 introduced into the solid roller in the manner shown in Figs. 2 and 3. The force sensors 107a, 107b shown in Fig. 4 each have a housing 120. A plug socket 122 is installed on one side of the respective housing 120. The respective force sensor 107a, 107b each has a piezo element 113 consisting of a multilayer crystal arrangement. The respective piezo element 113 is located between two force transmission disks 114, 115. The force transmission disks 114, 115 are connected to the housing 120 by means of elastic flanges 116. The sensor surface of the force sensor 107a is the outer surface of the force transmission disc 114 in contact with the bore wall of the bore 103.The sensor surface of the force sensor 107b is the outer surface of the force transmission disc 114 in contact with the bore wall of the bore 103.

[0101] To allow the circular, flat sensor surfaces of the force sensors 107a and 107b to rest against the walls of the bore 103, the bore 103 has a rectangular cross-section. Fig. 5 shows a schematic plan view, cut at the level of the upper bore wall, of the force sensors 107a, 107b arranged in the bore 103. Line 123 is shown in Fig. 5, which connects the point on the sensor surface of the first force sensor 107a that is closest to the sensor surface of the second force sensor 107b with the point on the sensor surface of the second force sensor 107b that is closest to the sensor surface of the first force sensor 107a. The sensor surface of the force sensor 107a is the outer surface of the force transmission disc 114 in contact with the bore wall of the bore 103. The sensor surface of the force sensor 107b is the outer surface of the force transmission disc 114 in contact with the bore wall of the bore 103.

[0102] Fig. 6 shows a holder 1101 for a force sensor 1102. The holder 1101 holds the force sensor 1102 in an axial bore 1103 of the measuring roller 1104 shown in detail. However, this type of holder can also be used, for example, to hold the force sensor 17 in the radially designed bore 13 in the embodiment according to Fig. 1.

[0103] The holder 1101 has an inner sleeve 1105, which consists of a first inner wedge element arranged above the installation position provided for the force sensor 1102

[0104] 1106 with an inner surface facing the installation position of the force sensor 1102

[0105] 1107 and an outer surface 1108 which is at an angle to the inner surface 1107 and opposite the inner surface 1107. Furthermore, the inner sleeve 1105 has a second inner wedge element 1109 arranged below the installation position provided for the force sensor 1102, which has an inner surface 1110 facing the installation position of the force sensor 1102 and an outer surface 1111 which is at an angle to the inner surface 1110 and opposite the inner surface 1110.

[0106] The holder 1101 further comprises an outer sleeve 1112. The outer sleeve 1112 comprises a first outer wedge element 1113 with an inner surface 1114 facing the installation position of the force sensor and an outer surface 1115 that is at an angle to the inner surface 1114 and opposite the inner surface 1114. The outer sleeve 1112 further comprises a second outer wedge element 1116 with an inner surface 1117 facing the installation position of the force sensor 1102, with which the outer wedge element 1116 rests on the outer surface of the second inner wedge element 1109. The outer wedge element 1116 further comprises an outer surface 1118 opposite the inner surface 1117.

[0107] A pressure screw 1119 with an external thread is screwed into an internal thread 1120 formed in the outer sleeve. The screw-in depth of the pressure screw 1119 determines the relative position of the inner sleeve 1105 in relation to the outer sleeve 1112 and thus the degree of preload of the holder 1101 in the axial recess 1103.

[0108] As can be seen from Fig. 7, the inner sleeve 1105 and the outer sleeve 1112 have slots 1121 and 1122, respectively. These longitudinal slots 1121, 1122 reduce the spring stiffness of the inner sleeve 1105 and the outer sleeve 1112, respectively, and ensure that the force shunt remains low. The compressive force to be determined, acting in the direction of arrow D, is therefore well introduced into the force sensor 1102. The outer sleeve 1112 and the inner sleeve 1105 can be manufactured in a first machining step by machining. As a result, the shape tolerance of the inner surfaces 1114, 1117 of the outer sleeve 1112 and the outer surfaces 1108, 1111 of the inner sleeve can be manufactured particularly precisely, thus enabling the inner sleeve 1105 to move relative to the outer sleeve 1112 without tilting moments. In subsequent processing steps, the dimensions shown in the view in Fig.9 laterally arranged regions of the inner sleeve 1105 are further narrowed in order to reduce the lateral wall thickness of the inner sleeve 1105. This creates lateral free spaces 1123, 1124 between the inner sleeve 1105 and the outer sleeve 1112 in the view of Fig. 7, which promote the introduction of force into the force sensor 1102 and further reduce the force shunt.

[0109] Figure 8 shows a top view of force sensor 1102. This view clearly shows the cable arrangement leading to force sensor 1102. A first cable 1125 leads to the illustrated force sensor 1102, while further cables 1126 lead to additional force sensors (not shown) arranged in the same axial recess 1103.

[0110] Fig. 9 shows the forces exerted on the measuring roller by a metal band partially wrapped around the measuring roller and subject to tension. The quartz force sensors 7a, 7b, 7c, 7d arranged in recesses in the measuring roller generate an electrical charge. This charge is directly proportional to the force applied to the quartz.

[0111] The strip length deviation, usually measured in I-Units, which is commonly used as a representative of the flatness of the strip, can be calculated using the following relationships

[0112] Local radial force in N

[0113] F R,i

[0114] Local tensile force in N

[0115] Fz,i = FR,i / (2 x sin a / 2) a = belt deflection angle around measuring roller

[0116] Local tensile stress in N / mm2

[0117] 6z,i = Fz,i / (b£| xd) bEI = measuring zone width d = strip thickness

[0118] Tensile stress deviation in N / mm2

[0119] A6z,i = 6z, max - 6z, i

[0120] 6z,max = maximum local tensile stress

[0121] Band length deviation in pm / m

[0122] AL / Lj=(A6z,i / E)x10 6

[0123] 5

[0124] E=E-module (stainless steel =2.06x10° N / mm2)

[0125] Band length deviation in I-Unit

[0126] 5

[0127] E=E-module (stainless steel =2.06x10° N / mm2)

[0128] Example:

[0129] Quartz force sensor: Sensitivity = 4.2 pC / N

[0130] Charge on the sensor: = 210 pC

[0131] Force on sensor: FR = 50 N

[0132] Fz,i =50 / (2 x 0.342 / 2) = 146.19 N a = 20° 6z, i= 146, 19 / (25x0.5)= 11 .69N / mm2 b£l =25mm,d=0.5mm A6z,i = 20 - 11 .69 = 8.3 N / mm2 6z, max = 20 N / mm2 AL / Lj = (A6z,i / E) x 10 6 =162.34 pm / m E = Young's modulus

[0133] 5

[0134] (Stainless steel = 2.06 x 10° N / mm2)

[0135] 5

[0136] AL / Lj = (A6z,i / E) x 10° = 16.234 I-Unit

[0137] The flatness, or strip length deviation, is the first property of the metal strip guided over the measuring roller 1 that can be determined using the measuring roller 1 according to the invention. The force sensors 7a, 7b, 7c, 7d are used for this purpose.

[0138] By providing the third force sensor 17 according to the invention and its arrangement differing from the arrangement of the force sensors 7a, 7b, 7c, 7d, a further property of the metal strip guided over the measuring roller 1 can now be determined, namely the overall strip tension acting on the metal strip. The invention is based on the assumption that the measuring roller body 1a bends due to the metal strip guided over it, which is subject to strip tension. This is illustrated schematically and exaggeratedly in Figs. 10 and 11. The measuring roller 1 is held by its pins 2 in bearings (not shown).

[0139] Fig. 11 highlights that a radial force FR acting on the measuring roller body 1a, causing it to bend, leads to compressive stresses in the material of the measuring roller body 1a in the area of ​​the measuring roller body that lies between the point of application of the radial force FR and the axis of rotation A (symbolized in Fig. 11 by the arrows 22 pointing towards each other). In the area of ​​the measuring roller body that lies beyond the axis of rotation A, starting from the point of application of the radial force FR, the radial force FR leads to tensile stresses in the material of the measuring roller body 1a (symbolized in Fig. 11 by the arrows 21 pointing away from each other). The force FR shown in Fig. 11 does not have to act vertically on the measuring roller 1. The point of application of the force FR depends on the wrap angle with which the belt wraps around the measuring roller 1, as well as on the point at which the belt runs onto the measuring roller 1.

[0140] Fig. 10 highlights that the compressive stresses lead to forces acting axially (parallel to the rotation axis A) on the third force sensor 17 (highlighted in Fig. 10 by corresponding arrows).

[0141] A radial coordinate system is defined to determine the strip tension. In the definition shown in Fig. 12 (the coordinate system can also be defined differently), the position "0°" is selected at the "3 o'clock position." The angle increases counterclockwise; thus, the "12 o'clock position" has an angle of 90°, the "9 o'clock position" has an angle of 180°, and the "6 o'clock position" has an angle of 270°.

[0142] According to the invention, the force F_Sensor measured by the sensor 17 is proportional to the deflection 23 of the roller body 1a, with the deflection 23 being proportional to the radial force F_Radial (= FR) acting on the roller body 1a. This can be expressed using the following formula:

[0143] F_Sensor = F_Radial * k, where k is a proportionality factor.

[0144] According to the findings of the invention, the radial force F_Radial acting on the roller body 1a is composed of: • a radial force F_Unbalance from an unbalance of the roller body 1a,

[0145] • a radial force F_radial band tension, which results from the desired band tension,

[0146] • a radial force from the dead weight F_weight of the measuring roller.

[0147] This can be expressed using the following formula, where the individual forces (F_Sensor, F_Radial, F_Unbalance, F_RadialBandTension, F_Weight) are scalars:

[0148] F_Radial = F_Unbalance + F_RadialBandTension + F_Weight.

[0149] The radial force F_unbalance is proportional to the square of the angular velocity of the measuring roller 10 according to the following equation:

[0150] F_unbalance = m * e * w 2, where m is the mass of the measuring roller 1 measured in kg and e is the eccentricity, i.e. the distance of the center of gravity of the mass from the pivot point of the measuring roller 10 (measured in m) and w is the angular velocity of the measuring roller 10 (measured in 1 / s, where the angular velocity w results from the rotational speed n (in 1 / min) by the relationship w = (n * TT * 2) / 60).

[0151] To determine the position of the center of mass (eccentricity), the known methods can be used, as explained, for example, at htps: / / de.wikipedia.org / wiki / Massenmittelpunkt (in the version available on May 30, 2022).

[0152] The radial force F_radial band tension is sinusoidal over the angle of rotation of the measuring roller 1 and can be expressed with the following equation: where ß corresponds to the angle at which the band wraps around the measuring roller (measured in °) and a corresponds to the angular position of the third force sensor in the coordinate system at the time of measurement (measured in °) and a_B corresponds to an average angular position (measured in °) of a contact surface, in particular the wrap between band-shaped material and measuring roller 1.

[0153] The radial force F_weight due to the weight force is sinusoidal over the angle of rotation and can be expressed with the following equation:

[0154] F_weight = m * g * sin(a + a_g), where m corresponds to the mass of the measuring roller 1 (measured in kg) and g corresponds to the acceleration due to gravity (expressed in m / (s*s)) and a corresponds to the angular position of the measuring roller 1 in the coordinate system at the time of measurement (measured in °) and a_g corresponds to an angular position (measured in °) to the vertical or to the acceleration due to gravity.

[0155] Fig. 12 and 13 show by way of example how the values ​​included in the above formula are determined for the coordinate system used here and for the illustrated embodiment.

[0156] The coordinate system is chosen so that the angle a = 0° is at the “3 o’clock position”.

[0157] The belt is guided over the measuring roller 1 such that the angle ß corresponds to approximately 60° in the embodiment shown here. The angle ß is usually constant, since the wrap angle of the belt around the measuring roller 1 results from the installation position of the measuring roller and the position of the units located upstream and downstream of the measuring roller 1.

[0158] The center of the wrap angle ß is located at an angle a_B from the "3 o'clock position". In the exemplary embodiment shown here, the angle a_B is approximately 120°. Typically, the angle a_B is a constant, as it results from the wrap angle and the position of the contact surface between the belt and measuring roller 1. The contact surface is the area with which the belt rests on the measuring roller and is a direct result of the wrap angle and the width of the belt. The position of the center of the contact surface results from the point - usually constant in the selected coordinate system - at which the belt runs onto the measuring roller and the point - usually constant in the selected coordinate system - at which the belt runs off the measuring roller. In the exemplary embodiment shown here, the angle a_g is 270°.The angle a_g is a constant because it results from the position of the chosen zero point of the coordinate system and its relative position to the force of gravity.

[0159] Figure 13 shows a snapshot in which the third force sensor 17 is located at the angular position a = 200°. Figure 13 also shows the position of the center of mass M and the eccentricity of the center of mass M relative to the rotation axis A.

[0160] Therefore, for the current measurement situation shown in Fig. 13, the following values ​​for the forces result (using the values ​​for ß, a_B, a_g also shown in Fig. 12):

[0161] F_unbalance = m * e * w 2 ,

[0162] F_Radialbandzug =

[0163] F_Bandzug * 2 * sin (0.5 * ß) * sin(a + a_B) =

[0164] F_Band tension * 2 * sin (0.5 * 60°) * sin(200° + 120°) =

[0165] F_Band tension * 2 * 0.866 * -0.643 =

[0166] F_Band tension * -1 ,114

[0167] For the current measurement situation shown in Fig. 13:

[0168] -> F_Bandzug = ((F_Sensor)Z * k - (m * e * w 2 ) - m * 9.218)Z -1 .114

[0169] Thus, knowing the angular velocity w (measurable via a rotary encoder on the bearing journal 2), the weight m of the measuring roller 1, the eccentricity e, and the proportionality factor k, the strip tension acting on the measuring roller 1 can be calculated from the force F_Sensor measured by the third force sensor 17. The proportionality factor k is determined experimentally. The procedure for determining the proportionality factor k is explained using the schematic diagram shown in Fig. 14.

[0170] Measuring roller 1 is mounted on rotating bearings 12. In a first step, measuring roller 1 is not loaded and does not rotate. As a result, the radial force F_unbalance is not present, since the radial force F_unbalance is only present during the rotation of measuring roller 1. Furthermore, there is no belt on measuring roller 1, so the radial force F_belt tension is also not present.

[0171] Thus, without rotation of the measuring roller 1, only the radial force F_weight is present. Accordingly, F_radial = F_weight. Therefore, the force measured with the third force sensor 17 is based solely on F_weight. The measuring roller is measured at several angular positions a, so that the effect of F_weight on the third force sensor is known for different angles. The force measured in this way at the third force sensor F_SENSOR_WEIGHT thus corresponds solely to the influence of the radial force F_weight.

[0172] Subsequently, the measuring roller is loaded with a reference force 14 using a punch 13 at the same angles. This loads the measuring roller 1 with a simulated radial force F_strip tension. Thus, in these cases, the simulated radial force F_strip tension and the radial force F_weight act on the measuring roller 1 and are measured by the third force sensor 17.

[0173] Since the influence of the radial force F_weight on the third force sensor is known, the influence of F_weight can be subtracted from the measured force. The measured force at the third sensor 17 is then divided by the simulated radial force F_belt tension to determine the proportionality factor k at the various angles:

[0174] The proportionality factor k can also be determined based on the angle, and the proportionality factor k can be extrapolated for an entire rotation from the determined values. Alternatively, the proportionality factor k can also be determined for each angle.

[0175] Fig. 15 is a graph showing the angle of rotation on the x-axis, where the angle of rotation indicates the position of the third force sensor 17 relative to the "zero position" of a selected coordinate system. The y-axis shows the resulting force or stress acting on the third force sensor 17 in the respective position.

[0176] The individual curves shown in Fig. 15 show singularly the effect of the respective effect considered, i.e. omitting other effects.

[0177] Curves A and B show the effect of the imbalance on the force measured by the third force sensor. Curves A and B therefore "ignore" the influence of gravitational acceleration and the influence of belt tension.

[0178] Since the position of the center of mass relative to the position of the third force sensor 17 is constant (see, for example, Fig. 13), the influence of the imbalance (F_Unbalance) depends on the angular velocity w, but not on the angle of rotation. Curve A shows the influence of the imbalance for a low angular velocity, while curve B shows the influence of the imbalance at a high angular velocity.

[0179] Curve C shows the influence of the weight force (F_weight). Curve C therefore "ignores" the influence of the imbalance and the influence of the belt tension. The influence of the weight force depends on the momentary application of the third force sensor 17 at the time of measurement in the selected coordinate system. At bottom dead center (in the selected coordinate system of Figs. 12 and 13, thus at a = 270°), the weight force increases the force measured by the third force sensor 17. At top dead center (in the selected coordinate system of Figs. 12 and 13, thus at a = 90°), the weight force reduces the force measured by the third force sensor 17.

[0180] Curves D and E show the effect of the belt tension on the force measured by the third force sensor 17. Curves D and E therefore “ignore” the influence of the imbalance and the influence of the weight. The influence of the belt tension and the weight force depends on the moment of the third force sensor 17 at the time of measurement in the selected coordinate system as well as on the position of the contact surface between the belt and the measuring roller. If the force sensor is exactly below the mean angular position in the selected coordinate system (exactly at a = a_B), the force sensor is subjected to a maximum compressive force. If the force sensor is exactly opposite the mean angular position in the selected coordinate system (exactly at a = 180 + a_B), the force sensor is subjected to a maximum tensile force. Curves D and E differ in the magnitude of the belt tension. In curve E, a higher belt tension acts on the belt than in curve D. Fig.Figure 16 shows a graph showing the forces acting on the measuring roller and the resulting force measured by the sensor. The x-axis shows the angular position a of the measuring roller, and the y-axis the applied or measured force. The radial force F_weight is sinusoidal with the rotation of the measuring roller. The radial force F_unbalance is constant, independent of the angle. The sum of the radial forces F_weight, F_unbalance, and F_radial belt tension results in the radial force F_radial acting on the roller body 1a. The radial force F_radial is related to the force F_sensor measured by the sensor 17 via the experimentally determined proportionality factor k.

Claims

Patent claims: Measuring roller (1) for determining a property of a strip-shaped material, in particular of metal strip, guided over the measuring roller (1), with • a measuring roller body (1 a) extending along a rotation axis (A) with a circumferential surface (20), • a recess (3) in the measuring roller body (1a), which is arranged at a distance from the peripheral surface (20) or leads from the peripheral surface (20) into the interior of the measuring roller body (1a), and a first force sensor (7, 7a) which is arranged in the recess (3), wherein the first force sensor (7, 7a) has a sensor surface and the first force sensor (7, 7a) can generate a sensor signal when the position of the sensor surface of the first force sensor (7, 7a) changes, wherein the sensor surface of the first force sensor (7, 7a) is arranged such that its position can be changed by a force which acts on it in a radial direction of the measuring roller body (1a), • and a second force sensor (7,7b), wherein • the second force sensor (7,7b) is either arranged in the recess (3) or • a further recess (3) is provided in the measuring roller body (1a), which is arranged at a distance from the circumferential surface (20) or leads from the circumferential surface (20) into the interior of the measuring roller body (1a), and the second force sensor (7, 7b) is arranged in the further recess (3), wherein the second force sensor (7, 7b) has a sensor surface and the second force sensor (7, 7b) can generate a sensor signal when the position of the sensor surface of the second force sensor (7, 7b) changes, wherein the sensor surface of the second force sensor (7, 7b) is arranged such that its position can be changed by a force acting on it in a radial direction of the measuring roller body (1a), characterized in that a third force sensor (17) is provided, wherein the third force sensor (17) • is arranged either in the recess (3) • or is arranged in the further recess (3) • or in the measuring roller body (1 a) a separate recess (13) is provided for the third force sensor (17), which is arranged at a distance from the peripheral surface (20) or extends from the peripheral surface (20) into the Interior of the measuring roller body (1 a), and the third force sensor (17) is arranged in this recess (13) provided for it, wherein the third force sensor (17) has a sensor surface and the third force sensor (17) can generate a sensor signal when the position of the sensor surface of the third force sensor (17) changes, wherein the sensor surface of the third force sensor (17) is arranged such that its position can be changed by a force which acts on it parallel to the axis of rotation (A) of the measuring roller body (1a).

2. Measuring roller according to claim 1, characterized in that the first force sensor (7,7a) and / or the second force sensor (7,7b) and / or the third force sensor (17) are each a piezoelectric force sensor, a strain gauge or an optical force sensor.

3. Measuring roller according to claim 1 or 2, characterized in that the third force sensor (17) is arranged closer to the peripheral surface (20) than to the axis of rotation (A).

4. Measuring roller according to one of claims 1 to 3, characterized in that a fourth force sensor is provided, wherein the fourth force sensor • is arranged either in the recess (3) • or is arranged in the further recess (3) • or is arranged in the recess (13) provided for the third force sensor • or a separate recess is provided in the measuring roller body for the fourth force sensor, which is arranged at a distance from the circumferential surface (20) or leads from the circumferential surface (20) into the interior of the measuring roller body (1 a), and the fourth force sensor is arranged in this recess provided for it, wherein the fourth force sensor has a sensor surface and the fourth force sensor can generate a sensor signal when the position of the sensor surface of the fourth force sensor changes, wherein the sensor surface of the fourth force sensor is arranged such that its position can be changed by a force acting on it parallel to the axis of rotation of the measuring roller body.

5. Measuring roller according to claim 4, characterized in that the third force sensor (17) and the fourth force sensor are arranged in a plane which is perpendicular to the axis of rotation (A). Method for determining a property of a strip-shaped material, characterized in that the strip-shaped material is guided over a measuring roller (1) according to one of claims 1 to 5 in such a way that the measuring roller (1) bends. Method for producing a measuring roller (1) according to one of claims 1 to 5, characterized in that the measuring roller (1) has at least one layer and that the layer is • Printing using a 3D printer, • Laser beam melting, • Electron beam melting, • Laser powder deposition welding • thermal spraying • Build-up welding • Contract soldering • a wire laser deposition welding, • a powder bed process, particularly preferably the so-called “Selective Laser Sintering” (SLS) or the so-called “Selective Laser Melting” (SLM), • Laser Metal Deposition (LMD), • Extremely high-speed laser cladding (EHLA) and / or • Arc welding with wire feed.

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