Measuring roll and its manufacturing method

Abstract

The present invention relates to a measuring roll for measuring at least one property, in particular strip tension, strip temperature, etc., of an article guided along the measuring roll, and to a method for manufacturing the measuring roll, the measuring roll having a measuring roll body (11) forming a circumferential surface (13) of the measuring roll, the measuring roll having at least one sensor mechanism (14) formed by at least one cavity (15) formed in the circumferential surface and accommodating at least one sensor, the cavity being designed to be closed by a lid (22) of the sensor mechanism flush with the circumferential surface, the lid being in mechanically operable connection with the sensor, the lid being materially joined to the measuring roll body and lying on the circumferential surface having a wall.

Description

[Technical Field]

[0001] The present invention relates to a measuring roll for measuring at least one property, in particular strip tension, strip temperature, etc., of an article guided along the measuring roll, and to a method for manufacturing the measuring roll, the measuring roll having a measuring roll body forming a circumferential surface of the measuring roll, the measuring roll having at least one sensor mechanism formed by at least one cavity formed in the circumferential surface and accommodating at least one sensor, the cavity being designed to be closed by a lid of the sensor mechanism so as to be flush with the circumferential surface, the lid being in mechanically operable connection with the sensor. [Background technology]

[0002] In particular, the above-described type of measuring roll and method is used to measure strip tension in strip material, particularly in the production of films, strips, or webs, such as aluminum foil. A measuring roll with multiple sensor mechanisms is known from DE 102 07 501 C1, where the sensor mechanisms are formed by drilled holes formed in the measuring roll body in the axial direction of the measuring roll and force sensors arranged therein. The drilled holes extend parallel to the circumferential surface of the measuring roll, and each force sensor is inserted into and supported therein so that the force acting on the circumferential surface, for example, from the strip, can be measured. An advantage of this method is that the circumferential surface is not affected by the sensor mechanisms and therefore always has the same material properties and is continuously or completely closed. A disadvantage, on the other hand, is that drilled holes formed parallel to the circumferential surface can only be formed at a safe distance from the circumferential surface, resulting in a relatively low measurement sensitivity of the force sensors. Furthermore, providing the drilled holes and arranging the sensors in the drilled holes requires a relatively large amount of effort. Therefore, a sensor mechanism designed in this way is only suitable for measuring large forces or tensions on thin strips or webs.

[0003] Measuring rolls such as those known from DE 42 36 657 A1 are typically used to measure relatively small tensions. Here, the sensor mechanism is designed so that drilled holes are formed in the circumferential surface of the measuring roll body and a force sensor is inserted into each of the drilled holes. The corresponding drilled holes are closed with lids that are flush with the circumferential surface of the measuring roll. The lids are relatively thick, like bungs, and are fixed in the drilled holes, for example, via a screw connection. This also makes it possible to pretension the force sensor. To achieve the highest possible measurement sensitivity, the lids need only move minimally within the drilled holes. To achieve this, a gap must be formed between the lid and the drilled holes. This gap is sealed using an O-ring, plastic material, adhesive material, or the like, which prevents, for example, dirt from entering the gap, i.e., the drilled holes. Overall, even small tensions in relatively thin strips can be measured in this manner. However, a disadvantage is that the required gap can easily leave an impression on the strip extending along the measuring roll. If the gap is not completely sealed, dirt can easily accumulate there, which can lead to errors in the measurement results. Therefore, it is also known to provide the measuring roll body with a so-called shrink ring in order to cover the drilled holes formed in the circumferential surface of the measuring roll body without leaving any gap. However, this type of shrink ring requires a wall thickness that adversely affects the measurement sensitivity and is relatively expensive to manufacture. Summary of the Invention

[0004] The object of the invention here is therefore to propose both a measuring roll and a method for its manufacture that allows for high measurement sensitivity without affecting the quality of the strip.

[0005] This object is achieved by a measuring roll having the features of claim 1 and a method for manufacturing a measuring roll having the features of claim 17.

[0006] A measuring roll for measuring at least one characteristic, in particular strip tension, strip temperature, etc., of an article guided along the measuring roll has a measuring roll body forming a circumferential surface of the measuring roll, the measuring roll having at least one sensor mechanism, the sensor mechanism being formed by at least one cavity formed in the circumferential surface and accommodating at least one sensor, the cavity being designed to be closed by a lid of the sensor mechanism so as to be flush with the circumferential surface, the lid being in mechanically operable connection with the sensor, the lid being materially joined to the measuring roll body, and the lid resting on the circumferential surface having a wall.

[0007] In the measuring roll according to the present invention, a cavity in the circumferential surface is formed radially with at least one sensor disposed therein. The lid completely closes the cavity, meaning that impurities cannot enter the gap or another opening in the sensor mechanism in the circumferential surface. However, the lid also forms the circumferential surface and is in mechanically operable connection with the sensor, so that forces acting directly on the circumferential surface can also act on the sensor, directly or indirectly, substantially via the lid. The gap-free design of the sensor mechanism is made possible by the lid being materially bonded to the measuring roll body. The materially bonded connection can be designed so that the sensor mechanism and / or cavity are completely and tightly sealed on the circumferential surface side. A gap-free connection, or a gap closed by a relatively soft material, can effectively prevent the formation of indentations on the strip. The materially bonded connection between the lid and the measuring roll body also allows the lid to be sufficiently thin, so that already small forces acting on the circumferential surface can be transmitted to the sensor via the lid. Overall, the measuring roll makes it possible to measure strip tension on, for example, relatively thin strips and / or webs, without the corresponding strips being affected by the measuring roll.

[0008] According to the present invention, the lid is preferably formed on a circumferential surface with a wall having a specific shape on the circumferential surface. The wall is formed to form a portion of the circumferential surface. The cavity is then at least completely covered by the wall. The outer contour of the wall can be designed to match the inner contour of the cavity. It is also possible for the outer contour of the wall to cover the inner contour of the cavity and / or for the cross section to be much larger than the cavity. It is important that the wall and / or its wall thickness are relatively thin compared to the cross section of the cavity opening. The wall can then also be material-bonded to the measuring roll body at its outer end and / or outer contour. A relatively thin wall can be very flexible, so that even very small forces can be transmitted to the sensor through the lid.

[0009] The cavity can be formed by a blind hole in the measuring roll body, which can extend radially relative to the measuring roll body. The blind hole can thus be formed perpendicular to the longitudinal axis of the measuring roll body and / or the measuring roll. The blind hole can be formed by drilling or milling. The blind hole can have a circular 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, etc. Then, multiple sensors can also be accommodated in the cavity.

[0010] The wall may have a wall thickness S, with the minimum wall thickness S being between 0.2 mm and 10 mm, preferably between 2 mm and 5 mm, and particularly preferably between 2 mm and 3 mm. At least a portion of the wall may be of uniform thickness. A portion of the wall forms a circumferential surface, so that on the circumferential surface of the wall, the wall has the radius of the measuring roll. Thus, the wall may be formed in the form of a curved plate with an elliptical profile and a uniform wall thickness. Alternatively, the wall may be manufactured by turning a plug or post inserted a few millimeters into the cavity. In particular, the wall thickness S may vary to some extent, for example within the ranges specified herein.

[0011] The sensor may be a force sensor, and the sensor mechanism may have a support for supporting the force sensor in the cavity and a pretensioning unit for a press-fit connection between the force sensor and the measuring roll. For example, the support may abut directly against the force sensor so that the force sensor is positioned and fixed in a precise position. The force sensor may be a piezoelectric sensor, and in this case the support may advantageously abut against an axial end of the force sensor and completely cover it. The pretensioning unit may be designed so that the force sensor is subjected to a defined pretensioning force. On the other hand, the pretensioning unit may be formed by or on the measuring roll body and / or by the support.

[0012] The axial end of the force sensor can be disposed between the bottom of the cavity and the support, and the support can completely cover the force sensor. The bottom of the cavity can be entirely flat so that the force sensor can be disposed directly on the bottom. Alternatively, the force sensor can be disposed on the bottom below an intermediate layer, such as a flat plate. If the support completely covers the force sensor, the force applied through the lid can also act completely on the force sensor. This can further improve the accuracy of the measurement.

[0013] The lid may form the support. In principle, the support may abut the lid, i.e., be arranged between the force sensor and the lid. If the lid forms the support, the support may be attached to the cavity together with the lid. This reduces the number of parts and simplifies the manufacture of the measuring roll.

[0014] The support may have an external thread that can be threaded into the internal thread of the bottom of the cavity. The support can then be positioned and fixed in the cavity particularly easily. The support may have a collar that can abut against the axial end of the force sensor. In addition, the force sensor can be designed in the shape of a ring or disk with a through hole. The support may then form a pretensioning unit, to which the force sensor can be fixed by threading the external thread into the internal thread in the cavity. The support can therefore be designed in the form of a screw or threaded pin.

[0015] Alternatively, the lid has a sleeve on its outer edge with an external thread that meshes with an internal thread on the inner wall of the cavity. The thread can be a fine thread so that the sleeve-like lid can be screwed into the cavity like a bung. After screwing in, a material-bonded connection with the measuring roll body can be formed. This thread design allows the lid to be positioned particularly precisely and simply in the cavity and to form a material-bonded connection.

[0016] The screw may form a pretensioning unit. For example, a collar may be formed on the support, by means of which a pretensioning force may be applied to the force sensor. The pretensioning force may be easily adjusted by means of the screw thread.

[0017] The support may be designed as a support pillar whose longitudinal axis is arranged to extend in a radial direction relative to the measuring roll body, and the support pillar may be arranged between the circumferential surface and the sensor. If a lid on the circumferential surface is formed together with the wall, the support pillar may thus be arranged between the wall and the sensor. Furthermore, the support pillar may be formed on the wall so that the lid forms the support pillar. The support pillar may be designed to be arranged coaxially relative to the lid and the cavity.

[0018] The lid may have an outer contour and a diameter D1 defining the outer contour, and the support may have a cross section at or adjacent to the wall formed on the circumferential surface by the lid and a diameter D2 defining a transverse cross section D2. The lid, or for example a blind hole in the cavity, may be formed with an outer diameter D1 such that the outer contour corresponds to the diameter D1. However, the lid and / or cavity may be designed such that the outer contour is within the diameter D1 and / or in its plane, which outer contour deviates at least partially from the diameter D1 by essentially any shape. The diameter D1 then corresponds to the relative distance from the two most distant points of the outer contour. The cross section of the support may correspond to the diameter D2. However, the support may be designed such that the cross section is within the diameter D2 and / or in its plane, which cross section deviates at least partially from the diameter D2 by essentially any shape. The diameter D2 then corresponds to the relative distance from the two most distant points of the cross section. If, for example, the support is designed as a rotating body and is arranged coaxially with the cavity in the wall or is molded onto the wall, an annular portion and / or annular wall is formed between the outer diameter D1 and the inner diameter D2. The forces acting on the circumferential surface in this area of ​​the lid can be transmitted evenly to the support. The annular wall then acts like a membrane or a spring, allowing even slight movements of the support in the direction of the longitudinal axis.

[0019] The diameter D1 may be in the range of 10 mm to 100 mm, preferably 10 mm to 50 mm.

[0020] The diameter D2 may be in the range of 2 mm to 50 mm, preferably 2 mm to 30 mm.

[0021] The ratio K of the diameter D1 to the diameter D2 can be between 1.1 and 100, preferably between 1.1 and 50. It has been proven that with the specified ratio, it is possible to achieve a sufficient force transmission via the support to the corresponding cross section of the force sensor or support for the cross section of the lid defined by the diameter D1. If another ratio is chosen, the lid may not be flexible enough, i.e. the desired transmission of forces acting on the lid or its circumferential surface to the support may not be ensured.

[0022] The lid can be connected to the measuring roll body by welding, preferably laser beam welding. A continuous weld seam can be formed along the outer contour of the lid in the region of the circumferential surface. The lid can be flush with the inner contour of the cavity or can partially cover the cavity. As a result, the weld can be formed with a butt joint or an lap joint between the lid and the measuring roll body. Accordingly, a shoulder can also be formed in the measuring roll body in the region of the circumferential surface where the lid is inserted or placed. This results in an lap joint with the measuring roll body. In particular, laser beam welding can be used as the welding process, since the materials to be joined are only slightly thermally affected and no filler is required. After welding, any weld seam, i.e., weld irregularities, between the circumferential surface of the lid and the circumferential surface of the measuring roll body can be smoothed in a further work step by machining, such as grinding and / or turning.

[0023] The materials of the lid, measuring roll body, and weld seam on the circumferential surface can be designed with matching hardness. This can be achieved by using similar or substantially similar materials, such as using the same steel for the lid material and the measuring roll body material. Additionally, the weld seam and the areas of the lid and measuring roll body surrounding the weld seam can be heat treated so that the hardness of the material in the area of ​​the weld seam is not significantly affected by the increase in temperature during welding.

[0024] The circumferential surface can be formed by surface treatment, preferably by overlay welding, preferably by laser overlay welding. This allows a relatively thin layer of material to be applied to the circumferential surface of the measuring roll body or the lid, and this material always has the same physical properties, especially strength properties. Such a surface treatment can also ensure that the circumferential surface has a relatively high hardness.

[0025] The measuring roll may have multiple sensor mechanisms, and the sensor mechanisms may be arranged in a uniform pattern across the circumferential surface of the measuring roll in both the circumferential and longitudinal directions. For example, the sensor mechanisms may be arranged at precisely the same distance from each other along the length of the measuring roll and / or radially around the circumference of the measuring roll. This allows for substantially continuous force detection when the filmstrip, for example, contacts the measuring roll, because one of the sensor mechanisms may always be in contact with the filmstrip. For example, the measuring roll may have 10, 40, 60, 100, or more sensor mechanisms. Preferably, the sensor mechanisms are formed or arranged in a spiral along the circumference of the measuring roll.

[0026] A method for manufacturing a measuring roll for measuring at least one property, in particular strip tension, strip temperature, etc., of an article guided along the measuring roll, comprises forming at least one cavity in the measuring roll body in a circumferential surface of the measuring roll body, accommodating at least one sensor in the cavity, closing the cavity with a lid, establishing a mechanically operable connection between the lid and the sensor, the lid being materially joined to the measuring roll body, and subsequently machining at least the lid so that it is flush with the circumferential surface. Regarding the advantages of the method according to the invention, please refer to the description of the advantages of the measuring roll according to the invention.

[0027] According to the invention, it is provided that when manufacturing the measuring roll, in particular the lid is materially joined to the measuring roll body. This material joining can be realized, for example, by welding. Machining of at least the lid is provided for in order to obtain a perfectly flush surface over the longitudinal direction of the measuring roll. During machining, material can also be removed from the measuring roll body. Machining can be carried out, for example, by grinding with a grinding wheel and / or by turning. Grinding and / or turning can also be carried out in several steps. Polishing of the circumferential surface is also possible. In addition, heat treatment of the circumferential surface can be provided, in whole or in part, for example in the region of the lid, in particular in the region of the material joining.

[0028] Further advantageous embodiments of the method result from the characterizing statements of the dependent claims which refer back to claim 1. [Brief explanation of the drawings]

[0029] The invention will be explained in more detail below with reference to the accompanying drawings. [Figure 1] FIG. 1 shows a perspective view of the measuring roll. [Figure 2] FIG. 2 shows a partial cross-sectional view of the sensor mechanism taken along line II-II in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0030] 1 shows a schematic diagram of a measuring roll 10, by means of which a measurement of the strip tension of a strip (not shown here), for example a metal foil, guided along the measuring roll 10 can be carried out. The measuring roll 10 is substantially formed by a measuring roll body 11, which is rotatable about a rotation axis 12. A plurality of sensor mechanisms 14 are formed on a circumferential surface 13 of the measuring roll 10, by means of which the forces acting on the circumferential surface 13 from one surface 13 to the other in the direction of the rotation axis 12 can be measured. The sensor mechanisms 14 are distributed substantially spirally over the circumferential surface 13 along the rotation axis 12, so that the strip abutting the measuring roll 10 or the circumferential surface 13 always overlaps with the sensor mechanisms 14, and the strip tension can be measured continuously.

[0031] FIG. 2 shows a schematic partial cross-sectional view of the sensor mechanism 14. In the measuring roll body 11, a cavity 15 is formed by a blind hole 16. In this context, the blind hole 16 extends radially of the measuring roll body 11, i.e., toward the rotation axis 12. A force sensor 17 is accommodated in the cavity 15 and fixed by a support 18. The force sensor 17 is connected to an evaluation means (not shown here) via a connecting cable 19. The connecting cable 19 exits the cavity 15 through a drilled hole 20 in the bottom 21 of the cavity 15. Furthermore, the cavity 15 is sealed flush with the circumferential surface 13 by a lid 22 of the sensor mechanism 14. For this purpose, the lid 22 is mechanically connected to the force sensor 17. Additionally, the lid 22 is material-bonded to the measuring roll body 11.

[0032] The lid 22 is formed on the circumferential surface 13 with a relatively thin wall 23 having a substantially uniform wall thickness S. The lid 22 also forms the support 18 or is formed integrally with the support 18. A post 24 of the support 18 extends from the wall 23 and is arranged so that its longitudinal axis 25 extends radially relative to the measuring roll body 11. The post 24 is designed to have a diameter D2. The post 24 or the support 18 further forms a collar 26. Axial ends 27 and 28 of the force sensor 17 are fixed between the bottom 21 of the collar 26 and the support surface 29, so that the force sensor 17 fits snugly against the collar 26. A threaded hole 30 is formed in the bottom 21, and a threaded pin 31 formed on the support 18 screws into the threaded hole 30. The threaded pin 31 passes through an opening 32 in the force sensor 17. By screwing the support 18 into the threaded hole 30, on the one hand the cavity 15 can be closed and on the other hand the force sensor 17 can be pretensioned as desired during assembly. The threaded hole 30 and the threaded pin 31 thus form a pretensioning unit 33.

[0033] The lid 22 is designed to have a diameter D1, which substantially corresponds to the diameter of the blind hole 16. Contrary to the illustration shown here, the lid 22 may protrude radially beyond the circumferential surface 13 to some extent when attached. This area of ​​the lid 22 is not shown here, but an internal hexagon or the like may be formed in this area, so that the lid 22 can be easily screwed on with the desired torque. The area of ​​the lid 22 not shown here can be removed after assembly is complete, for example by grinding, turning, or the like, the circumferential surface 13. After screwing on the lid 22, a weld seam 35 is formed by welding, in particular laser beam welding, along the outer contour 34 of the wall 23 between the wall 23 and the edge 36 of the blind hole 16 on the circumferential surface 13. The weld seam 35 is substantially circular or elliptical and completely closed, so that the lid 22 is materially joined to the measuring roll body 11. After welding, areas of the lid 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, a heat treatment of the lid 22 can be performed, particularly in the region of the circumferential surface 13. The fact that the wall 23 is relatively thin facilitates the transmission of forces acting radially on the circumferential surface 13 in the region of the lid 22 to the force sensor 17 via the support posts 24. This means that even relatively low strip tensions can be measured from a thin strip. Since the circumferential surface 13 is completely sealed by the material-bonded connection, no undesired contamination of the lid 22 in the region of the circumferential surface 13 or on the measuring roll body 11 can occur. Furthermore, no impressions from the sensor mechanism 14 on the strip can occur here.

Claims

1. A measuring roll (10) for measuring at least one characteristic, in particular the strip tension, the strip temperature, etc., of an article guided along the measuring roll (10), The measuring roll has a measuring roll body (11) that forms a circumferential surface (13) of the measuring roll, The measuring roll has at least one sensor mechanism (14), the sensor mechanism is defined by at least one cavity (15) formed in the circumferential surface and housing at least one sensor; the cavity is designed to be closed by a lid (22) of the sensor mechanism so as to be flush with the circumferential surface; the lid is in operable mechanical connection with the sensor; the lid is material-bonded to the measuring roll body; The lid on the circumferential surface has a wall (23). Measuring roll.

2. The cavity (15) is formed by a blind hole (16) in the measuring roll body (11), the blind hole extends in a radial direction relative to the measuring roll body; 2. The measuring roll of claim 1.

3. The wall (23) has a wall thickness S, and the minimum wall thickness S is 0.2 mm or more and 10 mm or less, preferably 2 mm or more and 5 mm or less, particularly preferably 2 mm or more and 3 mm or less.

3. A measuring roll according to claim 1 or 2.

4. The sensor is a force sensor (17), and the sensor mechanism (14) comprises a support (18) for supporting the force sensor in the cavity (15) and a pretensioning unit (33) for a press-fit connection between the force sensor and the measuring roll (10). A measuring roll according to any one of claims 1 to 3.

5. Axial ends (27, 28) of the force sensor (17) are arranged between the bottom (21) of the cavity (15) and the support (18); The support completely covers the force sensor.

5. The measuring roll of claim 4.

6. The lid (22) forms the support (18).

6. A measuring roll according to claim 4 or 5.

7. The support (18) has an external thread that meshes with an internal thread on the bottom (21) of the cavity (15). A measuring roll according to any one of claims 4 to 6.

8. the lid has a sleeve on its outer edge with external threads that mesh with internal threads on the inner wall of the cavity; A measuring roll according to any one of claims 4 to 6.

9. The screw forms a pretensioning unit (33).

9. A measuring roll according to claim 7 or 8.

10. the support (18) is designed as a strut whose longitudinal axis (25) is arranged in a radial direction relative to the measuring roll body (11), The support is disposed between the circumferential surface (13) and the sensor. A measuring roll according to any one of claims 4 to 9.

11. The lid (22) has an outer contour and a diameter D1 that defines the outer contour; the support (18) has a cross section at or adjacent to a wall (23) formed on the circumferential surface (13) by the lid and a diameter D2 defining the cross section D2; A measuring roll according to any one of claims 4 to 10.

12. D1 is 10 mm or more and 100 mm or less, preferably 10 mm or more and 50 mm or less.

12. The measuring roll of claim 11.

13. D2 is 2 mm or more and 50 mm or less, preferably 2 mm or more and 30 mm or less.

13. Measuring roll according to claim 11 or 12.

14. The ratio K of D1 to D2 is 1.1 or more and 100 or less, preferably 1.1 or more and 50 or less. Measuring roll according to any one of claims 11 to 13.

15. The lid (22) is connected to the measuring roll body (11) by welding, preferably by laser beam welding. A measuring roll according to any one of claims 1 to 14.

16. The measuring roll (10) has a plurality of sensor mechanisms (14) arranged in a uniform pattern over the circumferential surface (13) of the measuring roll in both the circumferential and longitudinal directions. A measuring roll according to any one of claims 1 to 15.

17. 1. A method for manufacturing a measuring roll (10) for measuring at least one property, in particular strip tension, strip temperature, etc., of an article guided along the measuring roll, comprising: At least one cavity (15) is formed in the measuring roll body (11) in the circumferential surface (13) of the measuring roll, At least one sensor is housed in the cavity; The cavity is closed by a lid (22), a mechanically operable connection is established between the lid and the sensor; the lid is material-bonded to the measuring roll body; At least the lid is then machined so that the lid is flush with the circumferential surface. method.

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