Measurement roller and method for producing same

Abstract

The invention relates to a measurement roller and to a method for producing a measurement roller in order to measure at least one property, in particular the strip tension, the strip temperature, or the like, of a product being guided over the measurement roller, comprising a measurement roller body (11) which forms a circumferential surface (13) of the measurement roller, wherein the measurement roller has at least one sensor assembly (14), and the sensor assembly is formed from at least one recess (15) which is made within the circumferential surface and in which at least one sensor is received. The recess is designed to be closed by a cover (22) of the sensor assembly so as to be flush with the circumferential surface, and the cover is operatively connected to the sensor in a mechanical manner. The cover is bonded to the measurement roller body, and the cover is formed with a wall (23) on the circumferential surface.

Description

[0001] Measuring roller and method for manufacturing

[0002] The invention relates to a measuring roller and a method for producing a measuring roller for measuring at least one property, in particular strip tensile stress, strip temperature or the like, of a material guided over the measuring roller, with a measuring roller body which forms a circumferential surface of the measuring roller, wherein the measuring roller has at least one sensor arrangement, wherein the sensor arrangement is formed by at least one recess formed within the circumferential surface, in which at least one sensor is accommodated, wherein the recess is closed with a cover of the sensor arrangement flush with the circumferential surface, wherein the cover is in a mechanical operative connection with the sensor.

[0003] Measuring rollers and methods of the type mentioned above are used in particular for measuring strip tensile stress in a strip material used to produce foils, strips or webs, such as in particular aluminum foil. DE 102 07 501 CI discloses a measuring roller which has a plurality of sensor arrangements which in turn are formed by bores formed in the axial direction of the measuring roller in a measuring roller body and force sensors arranged therein. The bores run parallel to a circumferential surface of the measuring roller, with the respective force sensors inserted into the bores and clamped therein in such a way that a force acting on the circumferential surface, for example from a strip, can be measured. The advantage here is that the circumferential surface is not influenced by the sensor arrangements and is therefore continuous or completely closed with always the same material properties.A disadvantage, however, is that the holes, which are drilled parallel to the circumferential surface, can only be positioned at a safe distance from the circumferential surface, resulting in comparatively low measurement sensitivity of the force sensors. The effort required to create the holes and arrange the sensors within them is also comparatively complex. Sensor arrangements designed in this way are therefore only suitable for measuring large forces or tensile forces on thicker strips or webs.

[0004] To measure comparatively small tensile forces, measuring rollers, as known from DE 42 36 657 A1, are regularly used. Here, sensor arrangements are designed such that bores are made in the circumferential surface of a measuring roller body, into each of which a force sensor is inserted. Each bore is closed with a cover that is flush with the circumferential surface of the measuring roller. The cover is designed like a plug and is comparatively thick and is fixed in the bore, for example by screwing. This also makes it possible to preload the force sensor. In order to achieve the highest possible measurement sensitivity, the cover can be moved minimally within the bore, which requires the formation of a gap between the cover and the bore. The gap is sealed, for example, by means of an O-ring, plastic material, adhesive material or the like, to prevent contamination from penetrating the gap.to prevent the hole. Overall, this means that even small tensile forces on relatively thinner strips can be measured. A disadvantage, however, is that the required gap can easily leave marks on the strip running over the measuring roller. If the gaps are not completely closed, dirt can easily accumulate in them, which can falsify the measurement result. It is therefore also known to provide a measuring roller body with a so-called shrink ring in order to cover holes formed in the circumferential surface of the measuring roller body without leaving a gap. However, shrink rings of this type require a wall thickness that has a negative effect on measurement sensitivity and are comparatively expensive to produce.

[0005] The present invention is therefore based on the object of proposing a measuring roller and a method for its production which enables a high measuring sensitivity without influencing the quality of the strip.

[0006] This object is achieved by a measuring roller having the features of claim 1 and a method for producing a measuring roller having the features of claim 17.

[0007] The measuring roller according to the invention for measuring at least one property, in particular strip tensile stress, strip temperature or the like, of a material guided over the measuring roller, has a measuring roller body which forms a circumferential surface of the measuring roller, wherein the measuring roller has at least one sensor arrangement, wherein the sensor arrangement is formed by at least one recess formed within the circumferential surface, in which at least one sensor is accommodated, wherein the recess is closed by a cover of the sensor arrangement flush with the circumferential surface, wherein the cover is in a mechanically operative connection with the sensor, wherein the cover is materially connected to the measuring roller body, wherein the cover is formed with a wall on the circumferential surface. In the measuring roller according to the invention, the recess is formed radially in the circumferential surface, wherein at least one sensor is arranged therein.The cover completely seals the recess, thus creating a gap-free seal, so that no contaminants can penetrate into a gap or other opening in the sensor arrangement in the circumferential surface. Nevertheless, the cover also forms the circumferential surface and is mechanically connected to the sensor, such that forces acting directly on the circumferential surface can also act directly or indirectly on the sensor, essentially via the cover. The gap-free design of the sensor arrangement is made possible by the cover being integrally connected to the measuring roller body. The integral connection can be designed such that the sensor arrangement or the recess is completely and tightly sealed on the circumferential surface side.By eliminating the gap or closing the gap with a relatively soft material, the formation of marks on the belt can be effectively prevented. The integral bond between the cover and the measuring roller body also makes it possible to make the cover sufficiently thin so that the already low forces acting on the circumferential surface can be transmitted to the sensor via the cover. Overall, the measuring roller enables the measurement of, for example, belt tensile stresses on relatively thin belts or webs without the respective belt being influenced by the measuring roller.

[0008] According to the invention, the cover is formed on the peripheral surface with a wall which preferably has a specific shape on the peripheral surface. The wall is designed such that it forms the peripheral surface in sections. The recess is then at least completely covered by the wall. An outer contour of the wall can be designed to match an inner contour of the recess. It can also be provided that an outer contour of the wall covers an inner contour of the recess or is designed to be slightly larger than the recess. It is important that the wall or a wall thickness of the wall is comparatively thin compared to an opening cross-section of the recess. The wall can then also be materially connected to the measuring roller body at its outer edges or at the outer contour.A comparatively thin wall can be so flexible that even very small forces can be transferred to the sensor via the cover.

[0009] The recess can be formed by a blind hole in the measuring roller body, which can run in the direction of its radius relative to the measuring roller body. Thus, the blind hole can be formed orthogonally relative to a longitudinal axis of the measuring roller body or the measuring roller. The blind hole can be formed by drilling or milling. The blind hole can have a round cross-section or, in principle, any other cross-section with a specific shape, for example, in the form of an elongated hole, a groove, an ellipse, an oval, a polygon, or the like. Thus, a plurality of sensors can also be accommodated in the recess.

[0010] The wall can be formed with a wall thickness S, wherein the minimum wall thickness S can be > 0.2 mm to < 10 mm, preferably > 2 mm to < 5 mm, particularly preferably > 2 mm to < 3 mm. The wall can then be formed to be of uniform thickness, at least in sections. Since the wall forms the circumferential surface in sections, the wall has a radius of the measuring roller on the circumferential surface of the wall. The wall can therefore be formed with a uniform wall thickness in the manner of a bent sheet with an elliptical contour. Alternatively, the wall can also be produced by turning a plug or punch which is inserted into the recess only a few mm. In particular, a wall thickness S can then also vary slightly, for example within the ranges specified here.The sensor can be a force sensor, wherein the sensor arrangement can have a support body for supporting the force sensor in the recess and a preload device for the force-locking connection of the force sensor to the measuring roller. The support body can, for example, bear directly against the force sensor so that the force sensor is correctly positioned and fixed. The force sensor can be a piezoelectric sensor, in which case the support body can advantageously bear against an axial end of the force sensor and completely cover it. The preload device can be designed such that the force sensor can be subjected to a defined preload force. The preload device can be formed on the one hand by the measuring roller body or on the measuring roller body and / or by the support body.

[0011] The force sensor can be arranged with its axial ends between a base of the recess and the support body, whereby the support body can completely cover the force sensor. The base of the recess can be completely flat, so that the force sensor can be positioned directly on the base. Alternatively, the force sensor can also be arranged on the base with a flat plate or the like interposed. If the support body completely covers the force sensor, a force introduced via the cover can also act entirely on the force sensor. This can further improve measurement accuracy.

[0012] The cover can form the support body. In principle, the support body can rest against the cover, i.e., be arranged between the force sensor and the cover. If the cover forms the support body, the support body can be attached to the recess together with the cover. This also makes it possible to reduce the number of parts, which simplifies production of the measuring roller. The support body can be designed with an external thread, which can be screwed to an internal thread in a base of the recess. The support body can then be positioned and fastened in the recess particularly easily. Furthermore, the support body can be designed with a collar, which can rest against an axial end of the force sensor. In addition, the force sensor can be ring-shaped or disc-shaped with a through-bore.The support body can then also form the preloading device, with which the force sensor can be fixed in the recess by screwing the external thread to the internal thread. The support body can therefore be designed in the form of a screw or a threaded pin.

[0013] Alternatively, the cover can be formed on its outer edge with a sleeve with an external thread, which can be screwed to an internal thread in an inner wall of the recess. The thread can be a fine thread, so that the sleeve-shaped cover can be screwed into the recess like a plug. After screwing in, the material-to-material connection with the measuring roller body can be formed. The design of the thread allows for particularly precise and simple positioning of the cover in the recess to create the material-to-material connection.

[0014] The threads can form the preload device. For example, a collar can be formed on the support body, through which a preload force can be exerted on the force sensor. The preload force can be easily adjusted via the thread.

[0015] The support body can be designed as a punch, which can be arranged with its longitudinal axis running relative to the measuring roller body in the direction of its radius, wherein the punch can be arranged between the peripheral surface and the sensor. If the cover is formed with a wall on the peripheral surface, the punch can consequently be arranged between the wall and the sensor. Furthermore, the punch can be molded onto the wall such that the cover forms the punch. The punch can be designed such that it is arranged coaxially relative to the cover and the recess.

[0016] The cover can be designed with an outer contour and a diameter D l delimiting the outer contour, wherein the support body can be designed on or adjacent to a wall formed by the cover on the peripheral surface with a cross section and a diameter D2 delimiting the cross section. The cover or, for example, a blind hole in the recess can be designed with the outer diameter D l such that the outer contour corresponds to the diameter D l. Nevertheless, the cover and / or the recess can be designed such that the outer contour lies within the diameter D l or in its plane, wherein the outer contour then deviates at least partially from the diameter D l due to its essentially arbitrary shape. The diameter D l then corresponds to a relative distance from the two furthest points of the outer contour. The cross section of the support body can correspond to the diameter D2.Nevertheless, the support body can be designed such that the cross-section lies within the diameter D2 or in its plane, whereby the cross-section then deviates at least partially from the diameter D2 due to its essentially arbitrary shape. The diameter D2 then corresponds to a relative distance between the two furthest points of the cross-section. If the support body is designed, for example, as a body of revolution and is arranged coaxially to the recess on the wall or is molded onto the wall, a circular ring or annular wall is formed between the outer diameter D1 and the inner diameter D2. A force acting on the circumferential surface in the region of the cover can then be transmitted evenly to the support body. The annular wall then acts like a membrane or spring, such that a movement of the support body in the direction of its longitudinal axis is possible, even if only minimal.

[0017] A dimension of the diameter D l can be in a range of D l > 10 mm to < 100 mm, preferably > 10 mm to < 50 mm.

[0018] A dimension of the diameter D2 can be in a range of D2 > 2 mm to < 50 mm, preferably > 2 mm to < 30 mm.

[0019] A ratio K of the diameter D1 to D2 can be > 1.1 to < 100, preferably > 1.1 to < 50. As has been shown, with the specified ratios it is possible to achieve sufficient force dissipation via the support body to the force sensor or a corresponding cross-section of the support body in relation to a cross-section of the cover, which is defined by the diameter D1. If other ratios are selected, the cover may not be sufficiently flexible or the desired introduction of the force acting on the cover or the circumferential surface into the support body cannot be ensured.

[0020] The cover can be connected to the measuring roller body by welding, preferably laser welding. In this case, it can be provided that a continuous weld seam is formed along an outer contour of the cover in the region of the circumferential surface. The cover can lie flush against an inner contour of the recess or cover the recess to a certain extent. Consequently, the welding can be formed at a butt joint between the cover and the measuring roller body or at a lap joint. In the measuring roller body, a shoulder can therefore also be formed in the region of the circumferential surface, in which shoulder the cover is inserted or arranged such that a lap joint is formed with the measuring roller body. In particular, it can be provided that laser beam welding is used as the welding process, since the materials to be joined are only slightly thermally influenced here and, if necessary, additional materials can be dispensed with.After welding, any weld seam or unevenness between the circumferential surface of the cover and the circumferential surface of the measuring roller body can be compensated in a further work step by machining, such as grinding and / or turning.

[0021] The material of the cover, the measuring roller body, and a weld seam on the peripheral surface can be designed with a consistent hardness. This can be achieved, for example, by using similar or essentially similar materials, for example, an identical steel for the cover material and the material of the measuring roller body. Furthermore, the weld seam and the areas of the cover and the measuring roller body surrounding the weld seam can be heat-treated in such a way that the hardness of the materials in the weld seam area is not significantly affected by a temperature increase during welding.

[0022] The peripheral surface can be formed with a surface coating by means of deposition welding, preferably laser deposition welding. This makes it possible to apply a comparatively thin layer of material to the peripheral surface of the measuring roller body or the cover, which layer always has the same physical properties, in particular strength properties. Such a surface coating can also ensure that the peripheral surface has a comparatively high degree of hardness.

[0023] The measuring roller can be designed with a plurality of sensor arrangements, which can be arranged in a uniform pattern over the circumferential surface in a circumferential direction and a longitudinal direction of the measuring roller. For example, the sensor arrangements can be arranged at a constant distance relative to one another in a longitudinal direction of the measuring roller and / or in a radial direction along a circumference of the measuring roller. This then makes it possible to essentially continuously detect a force when a film strip, for example, comes into contact with the measuring roller, since one of the sensor arrangements can then always come into contact with the film strip. For example, it can be provided that the measuring roller has 10, 40, 60, 100 or more sensor arrangements. The sensor arrangements are preferably designed or arranged in a spiral shape along the measuring roller with respect to a circumference of the measuring roller.

[0024] In the method for producing a measuring roller for measuring at least one property, in particular strip tensile stress, strip temperature or the like, of a material guided over the measuring roller, at least one recess is formed in the measuring roller body within a circumferential surface of a measuring roller body of the measuring roller, wherein at least one sensor is received in the recess, wherein the recess is closed with a cover, wherein the cover is brought into a mechanical operative connection with the sensor, wherein the cover is materially connected to the measuring roller body, wherein at least the cover is subsequently machined such that the cover is formed flush with the circumferential surface. For the advantages of the method according to the invention, reference is made to the description of the advantages of the measuring roller according to the invention.

[0025] According to the invention, during production of the measuring roller, it is particularly provided that the cover is integrally connected to the measuring roller body. This integral connection can be effected, for example, by welding. In order to obtain a completely flat surface relative to a longitudinal extent of the measuring roller, machining of at least the cover is provided. During machining, material can also be removed from the measuring roller body. The machining can be carried out, for example, by grinding with a grinding wheel and / or turning. The grinding and / or turning can also be carried out in several work steps. Furthermore, it can be provided that the peripheral surface is machined by polishing. In addition, heat treatment of the peripheral surface as a whole or partially, for example in the area of ​​the cover and in particular of the integral connection, can be provided.

[0026] Further advantageous embodiments of the method emerge from the descriptions of the features of the subclaims which refer back to claim 1.

[0027] The invention is explained in more detail below with reference to the accompanying drawings.

[0028] They show:

[0029] Fig. 1 is a perspective view of a measuring roller;

[0030] Fig. 2 is a partial sectional view of a sensor arrangement along a line II-II of Fig. 1.

[0031] Fig. 1 shows a schematic representation of a measuring roller 10 by means of which a measurement of the strip tension of a strip (not shown here), for example a metal foil or the like, can be carried out and guided over the measuring roller 10. The measuring roller 10 is essentially formed from a measuring roller body 11 which is rotatable about a rotation axis 12. A plurality of sensor arrangements 14 are formed on a circumferential surface 13 of the measuring roller 10, by means of which sensor arrangements 14 a force acting from the circumferential surface 13 in the direction of the rotation axis 12 onto the circumferential surface 13 can be measured. The sensor arrangements 14 are arranged distributed essentially spirally over the circumferential surface 13 along the rotation axis 12, so that a strip resting against the measuring roller 10 or the circumferential surface 13 always overlaps with a sensor arrangement 14, and thus a strip tensile stress can be continuously measured. Fig.2 shows a partial sectional view of a sensor arrangement 14 in a schematic representation. In the measuring roller body 11, a recess 15 is formed by a blind hole 16. The blind hole 16 runs in the direction of a radius of the measuring roller body 11 or towards the rotation axis 12. A force sensor 17 is accommodated within the recess 15 and fixed by means of a support body 18. The force sensor 17 is connected to evaluation means (not shown here) via a connecting cable 19. The connecting cable 19 is led out of the recess 15 via a bore 20 in a base 21 of the recess 15. Furthermore, the recess 15 is closed with a cover 22 of the sensor arrangement 14, flush with the peripheral surface 13. The cover 22 is in a mechanical operative connection with the force sensor 17. In addition, the cover 22 is materially connected to the measuring roller body 11.

[0032] The cover 22 is formed on the peripheral surface 13 with a wall 23 which is relatively thin and has a substantially uniform wall thickness S. The cover 22 also forms the support body 18 or is formed integrally with it. Starting from the wall 23, a punch 24 of the support body 18 extends, which is arranged with its longitudinal axis 25 relative to the measuring roller body 11 in the direction of its radius. The punch 24 is formed with a diameter D2. Furthermore, the punch 24 or the support body 18 forms a collar 26. The force sensor 17 is now clamped with its axial ends 27 and 28 between the base 21 and a support surface 29 of the collar 26, resting flat against the latter. A threaded bore 30 is formed in the base 21, into which bore a threaded pin 31 formed on the support body 18 is screwed. The threaded pin 31 penetrates a through hole 32 in the force sensor 17.By screwing the support body 18 into the threaded bore 30, it is possible, on the one hand, to close the recess 15 and, on the other hand, to preload the force sensor 17 as desired during assembly. The threaded bore 30 and the threaded pin 31 thus form a preloading device 33.

[0033] The cover 22 is formed with a diameter D l which essentially corresponds to a diameter of the blind hole 16. Deviating from the illustration shown here, when the cover 22 is installed, it can project radially beyond the circumferential surface 13 by a certain amount. In this area of ​​the cover 22, which is no longer shown here, a hexagon socket or the like can be formed, for example, so that the cover 22 can then be screwed in easily and with a desired torque. The area of ​​the cover 22 (not shown) can be removed after installation, for example by grinding, turning or the like of the circumferential surface 13. After the cover 22 has been screwed in, a weld seam 35 is formed along an outer contour 34 of the wall 23 by means of welding, in particular laser beam welding, between the wall 23 and an edge 36 of the blind hole 16 on the circumferential surface 13.The weld seam 35 is essentially circular or oval and completely closed, so that the cover 22 is firmly bonded to the measuring roller body 11. After welding, the area of ​​the cover 22 (not shown here) can be removed by grinding and / or turning. Overall, this makes it possible to form a completely closed circumferential surface 13.

[0034] Optionally, heat treatment can be provided, in particular of the cover 22 in the region of the circumferential surface 13. Because the wall 23 is comparatively thin, a transmission of force acting radially on the circumferential surface 13 in the region of the cover 22 via the punch 24 to the force sensor 17 is easily possible. In this way, even comparatively low strip tensile stresses of thin strips can then be measured. Since the circumferential surface 13 is completely closed by the material connection, there can be no undesired contamination of the cover 22 in the region of the circumferential surface 13 or on the measuring roller body 11. Furthermore, impressions of sensor arrangements 14 on a strip are not possible here.

Claims

Patent claims 1. Measuring roller (10) for measuring at least one property, in particular strip tensile stress, strip temperature or the like, of a material guided over the measuring roller, with a measuring roller body (11) which forms a circumferential surface (13) of the measuring roller, wherein the measuring roller has at least one sensor arrangement (14), wherein the sensor arrangement is formed by at least one recess (15) formed within the circumferential surface, in which at least one sensor is accommodated, wherein the recess is closed off by a cover (22) of the sensor arrangement flush with the circumferential surface, wherein the cover is in a mechanical operative connection with the sensor, characterized in that the cover is materially connected to the measuring roller body, wherein the cover is formed with a wall (23) on the circumferential surface.

2. Measuring roller according to claim 1, characterized in that the recess (15) is formed by a blind hole (16) in the Measuring roller body (11) which runs relative to the measuring roller body in the direction of its radius.

3. Measuring roller according to claim 1 or 2, characterized in that the wall (23) is formed with a wall thickness S, wherein the minimum wall thickness S is > 0.2 mm to < 10 mm, preferably > 2 mm to < 5 mm, particularly preferably > 2 mm to < 3 mm.

4. Measuring roller according to one of the preceding claims, characterized in that the sensor is a force sensor (17), wherein the sensor arrangement (14) has a support body (18) for supporting the force sensor in the recess (15) and a pretensioning device (33) for the force-locking connection of the force sensor to the measuring roller (10).

5. Measuring roller according to claim 4, characterized in that the force sensor (17) is arranged with its axial ends (27, 28) between a bottom (21) of the recess (15) and the support body (18), wherein the support body completely covers the force sensor.

6. Measuring roller according to claim 4 or 5, characterized in that the cover (22) forms the support body (18).

7. Measuring roller according to one of claims 4 to 6, characterized in that the support body (18) is formed with an external thread, which is screwed with an internal thread in a bottom (21) of the recess (15).

8. Measuring roller according to one of claims 4 to 6, characterized in that the cover is formed on its outer edge with a sleeve with an external thread which is screwed to an internal thread in an inner wall of the recess.

9. Measuring roller according to claim 7 or 8, characterized in that the threads form the pretensioning device (33).

10. Measuring roller according to one of claims 4 to 9, characterized in that the support body (18) is designed as a stamp (24) which is arranged with its longitudinal axis (25) relative to the measuring roller body (11) running in the direction of its radius, wherein the stamp is arranged between the circumferential surface (13) and the sensor.

11. Measuring roller according to one of claims 4 to 10, characterized in that the cover (22) is designed with an outer contour and a diameter D1 delimiting the outer contour, wherein the support body (18) is designed on or adjacent to a wall (23) formed by the cover on the peripheral surface (13) with a cross section and a diameter D2 delimiting the cross section.

12. Measuring roller according to claim 11, characterized in that Dl is > 10 mm to < 100 mm, preferably > 10 mm to < 50 mm.

13. Measuring roller according to claim 11 or 12, characterized in that D2 is > 2 mm to < 50 mm, preferably > 2 mm to < 30 mm.

14. Measuring roller according to one of claims 11 to 13, characterized in that a ratio K of Dl to D2 is > 1.1 to < 100, preferably > 1.1 to < 50.

15. Measuring roller according to one of the preceding claims, characterized in that the cover (22) is connected to the measuring roller body (11) by welding, preferably laser beam welding.

16. Measuring roller according to one of the preceding claims, characterized in that the measuring roller (10) is formed with a plurality of sensor arrangements (14) which are arranged over the circumferential surface (13) in a circumferential direction and a longitudinal direction of the measuring roller in a uniform pattern.

17. Method for producing a measuring roller (10) for measuring at least one property, in particular strip tension, strip temperature or the like, of a material guided over the measuring roller, wherein within a circumferential surface (13) of a measuring roller body (11) of the measuring roller at least one recess (15) is formed in the measuring roller body, wherein in the recess at least one Sensor is received, wherein the recess is closed with a cover (22), wherein the cover is brought into a mechanical operative connection with the sensor, characterized in that the cover is materially connected to the measuring roller body, wherein subsequently at least the cover is machined in such a way that the cover is formed flush with the peripheral surface.

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