Calender for producing very high line forces, and method for operating a calender

Abstract

The invention relates to a calender (100) for calendering flat structures (10), preferably in order to produce electrodes, having a first roller (1) and a second roller (2). The rollers (1, 2) can be moved relative to each other along a first axial direction (A1) of the first roller (1) and / or a second axial direction (A2) of the second roller (2). The first roller (1) has a first profile (P1), and the second roller (2) has a second profile (P2). The calender (100) has a tilting means (7) for tilting the first roller (1) and the second roller (2) about a tilt axis (V), said tilt axis (V) being perpendicular to the first axial direction (A1) and the second axial direction (A2). The invention additionally relates to a method for operating a calender (100).

Description

[0001] Calender for generating highest line forces, method for operating a calender

[0002] The invention relates to a calender for calendering flat structures, preferably for producing electrodes, comprising a first roll and a second roll. Furthermore, the invention relates to a method for operating a calender.

[0003] For calendering fabrics, the fabrics are typically fed along a fabric direction into a nip between two work rolls of a calender. The fabric passes through the nip and is subjected to pressure by the calender rolls.

[0004] Modern calender applications require the utmost precision in calender operation. Precise dimensioning of the roll gap is of utmost importance. Particular attention is paid to the defined setting, and in particular the consistency, of the roll gap height – also referred to as gap height – across its entire width, i.e., transverse to the fabric direction. Ensuring that the actual roll gap height corresponds to the desired height is counteracted by operational difficulties that regularly occur as a result of the inherent principles of the process. One example of a problem is the deflection of the rolls during calendering of a fabric. This deflection is typically due to deformation of the rolls when force is applied to the fabric. During calendering, the rolls deform due to the linear forces in the roll gap.However, especially when high levels of accuracy are required, other effects also become the focus of attention. For example, the rollers expand with increasing temperatures. A completely homogeneous temperature distribution is not possible, especially with heated rollers. Typically, the temperature of heated rollers drops at the edges, for example due to cooled bearings or a larger surface area through which heat can be dissipated. The inhomogeneous temperature distribution of heated rollers leads to inhomogeneous thermal expansion and thus also contributes to unwanted deviations in the gap height, which contributes to deflection in the sense of the present invention. Furthermore, undesirable effects occur in the roller gap at the edge of the calendered sheet, which contribute to deflection in the sense of the present invention.The force applied by the rollers to the calendered fabric causes the rollers to flatten in the areas in contact with the web. Outside of these areas, the rollers are not flattened by contact with the fabric. This creates shear stresses in the rollers at the edges of the calendered fabric, which deform the rollers and thus influence the roll gap. The effect described here reduces the gap height toward the edge of the calendered fabric, leading to an undesirable increase in the line force in the roll gap toward the edge of the calendered fabric.

[0005] State-of-the-art methods for dealing with, preventing, or compensating for roll deflection are known. One possibility is the use of ram-supported rolls, in which a device is provided inside the rolls that compensates for deflection of the roll shell by applying mechanical forces that counteract the deflection.

[0006] This technology becomes problematic in applications where extremely high precision is required while applying very high line forces. For example, the thin roll shells of ram-supported rolls cannot be manufactured with unlimited precision. Furthermore, ram-supported rolls are performance-limited in terms of the maximum line forces that can be applied. Finally, it is difficult to heat ram-supported rolls very evenly.

[0007] A constantly growing field of application for calenders is the production of electrodes for battery production. In this process, conductive foils are coated and then calendered. Calendering determines the density of the electrodes, their porosity, their adhesive strength, and, with these parameters, their conductivity and ultimately their electrochemical performance. Accuracies of 1 pm gap height relative to the roll gap are required across the entire width of the roll gap, with line forces ranging from over 500 N / mm to 10,000 N / mm.

[0008] Currently, calenders are used to produce electrodes with a web width typically not exceeding 800 mm. Larger web widths result in roll deflections that cannot be satisfactorily compensated for using conventional methods. For example, applying crowning to the rolls is inflexible, especially under varying line forces. Nevertheless, larger web widths are desirable because they significantly improve electrode production efficiency.

[0009] It is therefore an object of the present invention to provide a calender and a method for operating a calender which do not have the disadvantages of the prior art described, but offer the possibility of a very uniform adjustment of the roll gap at high line forces and large web widths.

[0010] This problem is solved by the features of claim 1 and claim 8.

[0011] The calender according to the invention for calendering sheet materials has a first roll and a second roll. The calender is preferably intended for calendering electrodes. The first roll and the second roll are working rolls of the calender. For example, it is conceivable that the first roll is an upper roll and the second roll a lower roll of the calender. However, it is also conceivable that the second roll is an upper roll and the first roll a lower roll of the calender. Furthermore, it is possible for the first roll and the second roll to be arranged next to one another and for the sheet material to be guided from above, from below, or obliquely between the first roll and the second roll. It is also conceivable for the first roll and the second roll to be inclined, i.e. for the axial directions of the rolls to be non-horizontal.Finally, it is conceivable that the rolls of the calender are aligned such that the nip plane is inclined, in particular not vertical, when the rolls are not interlaced, i.e., when the axial directions of the rolls are aligned parallel. The nip plane is the plane in which the axial directions of both rolls lie in an interlaced state, i.e., with an interlacing angle of zero. The present invention is not limited to a calender having only two rolls. In addition to the first roll and the second roll, the calender according to the invention can have additional rolls.

[0012] According to the invention, the first roller can be displaced along a first axial direction of the first roller and / or the second roller can be displaced along a second axial direction of the second roller. The axial directions correspond to the respective roller axes, i.e., the axes around which the roller rotates during operation. Thus, the rollers can be displaced relative to one another.

[0013] In addition, the calender according to the invention has an interlacing means for interlacing the first roll and the second roll. At least one of the rolls rotates about an interlacing axis that is perpendicular to the first axial direction and perpendicular to the second axial direction. The interlacing axis can be arranged centrally on the first roll and / or the second roll, but it does not have to be. If the interlacing axis is arranged centrally on the first and second rolls, the interlacing axis can be said to be centrally arranged. If the interlacing axis is not arranged centrally on the first and second rolls, the interlacing axis is arranged eccentrically.

[0014] The interlacing of the rollers makes it possible to adjust the gap height in the center of the roller gap as well as at the outer ends. If, for example, the roller gap is narrower at the ends than in the center, the rollers can be interlaced around a centrally located interlacing axis. This moves the rollers further apart at the ends while the distance in the center remains the same. If the roller gap is narrower at a first outer end than at a second outer end, the rollers can be interlaced around an interlacing axis located at the second outer end. The rollers thus move further apart at the first outer end.The effect of interlacing always leaves one point of the roll gap unchanged, namely the point through which the interlacing axis passes, and corrects the remaining areas either towards a larger roll gap (increasing the interlacing angle between the first axial direction and the second axial direction) or towards a smaller roll gap (reducing the interlacing angle). Interlacing ensures good and simple compensation of the deflection in a first approximation. A better-resolved compensation of the deflection, i.e. compensation that can be adjusted much more freely with regard to the location of the compensation, cannot be achieved through interlacing. In particular, the combination of interlacing and shifting along the axial directions also makes it possible to specifically compensate for unwanted deviations in the gap height caused by inhomogeneous roll temperatures.

[0015] To achieve this improved resolution for compensating for undesirable gap height deviations, the rollers are shifted relative to each other along the axial direction. Shifting the rollers changes the gap height profile. The combination of shifting the rollers along the axial direction and thus adjusting the gap height profile by shifting the profiles relative to each other and interlacing the rollers allows the gap height to be adjusted with high precision and reliability, even for very large web widths, such as 1,500 mm or more, even under very high line forces.

[0016] Advantageous embodiments and further developments of the invention can be found in the dependent claims and the description with reference to the drawings. According to a preferred embodiment of the present invention, the first roller has a first profile. The second roller has a second profile. The profiles of the rollers are surface topographies of the circumferential surfaces of the rollers and relate to the course of the extension of the rollers orthogonal to the respective axial direction along the respective axial direction. The profiles are provided in particular so that a desired course of the gap height and in particular a uniform gap height of the roller gap between the rollers is generated by the displacement along the axial directions.The first profile and / or the second profile preferably has a 0.5 S shape or a multiple thereof, in particular a 1 S shape, a 1.5 S shape, a double S shape or a 2.5 S shape. It is preferably provided that the first profile and / or the second profile has at least or exactly one, at least or exactly two or preferably at least or exactly three turning points. The first and the second roller are therefore not cylindrical or frustoconical, but have regions of different pitch across the roller width. This results in different roller diameters along the roller widths, which have a non-linear profile along the axial direction. Non-linear preferably also includes a series of several non-parallel linear sections.Depending on the relative position of the rollers along the axial direction, the diameter deviations of the two rollers compensate for each other, so that a desired, particularly uniform, gap height can be precisely adjusted according to the requirements. An S-shape has two opposing curves. A 1.5-S shape has three opposing curves. A double-S shape has four opposing curves. In addition to the explicitly mentioned 0.5-S, S, 1.5-S, and double-S shapes, other profiles are conceivable that include other numbers, especially larger numbers, of S-shapes, for example 1.75-S shape, 2.5-S shape, 3-S shape, and so on.

[0017] In particular, it is provided that the profiles each have a polynomial curve of at least or exactly third degree, or at least or exactly fourth degree, or at least or exactly fifth degree. It is conceivable that a crown is superimposed on the 0.5 S-shape, the S-shape, the 1.5 S-shape, and / or the double S-shape of the first roller. It is conceivable that, alternatively or additionally, a crown is superimposed on the S-shape, the 1.5 S-shape, and / or the double S-shape of the second roller.

[0018] During axial displacement, the areas in which compensation is applied can be freely selected by adjusting the profiles accordingly. By selecting appropriate profiles, a high degree of freedom is achieved to influence the roll gap in a highly customized manner, particularly with regard to the number of affected points, the locations of the influence within the roll gap, and the width of the affected areas.

[0019] A polynomial curve, or the characteristic that a profile has a polynomial of at least or exactly a certain order, is not to be understood in a slavishly mathematical sense. Rather, it should be viewed as a description of the essential form of the respective profile, as is sufficient for a person skilled in the art in everyday language. Thus, it is conceivable that in practice, the profiles are described not by mathematical functions but by tables of values ​​with disjoint extensions of the respective roller in the radial direction as a function of the axial direction. If the vast majority of the values ​​in the table of values ​​can be approximated within technical-practical error limits using a polynomial curve, then the respective profile, within the meaning of the present invention, corresponds precisely to this polynomial.If individual values ​​or smaller ranges of the value table are such that they cannot be approximated within the technical-practical error limits by the polynomial progression, this does not detract from what has been described above.

[0020] According to a further preferred embodiment of the present invention, the first profile and the second profile are designed such that, in a relative position of the first or second roller, the roller gap has a desired and, in particular, a uniform gap height along the axial direction when the interlacing device interlaces the first and second rollers by an interlacing angle about the interlacing axis, wherein the interlacing angle is preferably not equal to zero. In other words, the interlacing of the rollers is already taken into account when shaping the first profile and the second profile. This makes it possible to compensate for deviations from the desired gap height profile that are introduced by the interlacing itself or cannot be compensated for by the interlacing alone.

[0021] According to a preferred embodiment of the present invention, the deflection in the roll center is fully compensated by interleaving the rolls, and the resulting overcompensation at the quarter points is compensated for by shifting the rolls relative to each other along the axial direction. For this purpose, it is preferably provided that the first profile and / or the second profile have a double S shape. For this purpose, it is provided, for example, that the first profile and / or the second profile correspond to a polynomial of at least or exactly the fifth degree.

[0022] If the deflection is compensated only by means of axial displacement, it is conceivable that the first profile and the second profile each have an S-shape and preferably correspond to a polynomial of at least or exactly third order.

[0023] Alternatively, the distribution of the roll gap correction to achieve the desired roll gap profile can also be chosen differently between interlacing and axial displacement. For example, it is conceivable that the deflection is only partially compensated, for example, two-thirds, by interlacing the rolls, and the remaining compensation is achieved by axial displacement. It is conceivable that the first profile and / or the second profile only have an S-shape for this purpose. For this purpose, it is provided, for example, that the first profile and / or the second profile correspond to a polynomial of at least or exactly the third degree.

[0024] In particular, it is conceivable that the quarter points are also specifically influenced. For this purpose, a different distribution of the compensation through interlacing and axial displacement is provided. For this purpose, an overlay of the S-shape with a double S shape of the first profile and the second profile is preferably provided. For this purpose, it is provided, for example, that the first profile and the second profile correspond to a polynomial of at least or exactly the fifth degree. If, for example, the roll gap is to be narrowed at the quarter points, the proportion of compensation through interlacing is increased and the proportion of compensation through axial displacement is reduced. If, on the other hand, the roll gap is to be narrowed less at the quarter points, the proportion of compensation through axial displacement is increased, while the interlacing is reduced.

[0025] It is also conceivable that the deflection is compensated by twisting until overcompensation is just avoided, especially at the quarter points. The remaining deflection, especially the deflection in the center of the roll gap, is compensated by displacement along the axial direction. For this purpose, the first profile and / or the second profile has an S-shape. By changing the proportions of twisting and axial displacement, the gap heights at the quarter points and in the roll center can also be influenced differently.

[0026] It is also conceivable that the deflection is deliberately overcompensated by means of interlacing in the center of the roll gap, so that the interlacing alone, i.e., without the influence of axial displacement, results in only a slight variation in the roll gap height profile from the center of the roll gap to the quarter points and essentially remains constant. To compensate at the edges of the roll gap, i.e., outside the quarter points, an S-shape with an elongated S extending over the length of the roll gap would be necessary.

[0027] It is therefore possible to influence the roll gap in completely different ways by differently distributing the contributions of axial displacement and interlacing to deflection compensation, thus taking into account technical conditions that would otherwise not have been possible due to the design principle. The flexibility gained by combining axial displacement and interlacing is a significant advantage in extremely precise calendering with the highest line forces, as is necessary for calendering electrodes.

[0028] This flexibility is further increased if, in addition to or as an alternative to axial displacement and interlacing, asymmetrical pressure is applied to the first roller and / or the second roller. It is conceivable that this will cause a tilting of at least one of the rollers. The asymmetrical pressure can be generated by applying unequal forces to the opposing main bearings of a roller, in particular by applying forces that are adjusted independently of each other at the opposing main bearings of a roller.

[0029] Roughly five zones of the roll gap can be influenced by applying a portion of symmetrical pressure, a portion of interlacing, an eccentric arrangement of the interlacing axis, a portion of asymmetrical pressure, and a portion of axial displacement. These five zones are the two quarter points, the area of ​​the roll gap centers between the quarter points, and the edges of the roll gap, i.e. the areas between the quarter points and the roll necks. In particular, a combination of axial displacement, interlacing, and preferably also asymmetrical pressure can also influence the edges of the area of ​​the roll gap that is in contact with the fabric. This is particularly advantageous because these areas are often critical during calendering, and the fabric outside the quarter points is often not calendered with satisfactory accuracy.

[0030] A significant increase in flexibility is achieved through interlacing with a centrally or eccentrically arranged interlacing axis and asymmetrical pressure application. With only symmetrical pressure application or with only interlacing around a centrally arranged interlacing axis, the edges of the roll gap are affected equally. Likewise, with only symmetrical pressure application or symmetrical interlacing with a central interlacing axis, the quarter points are affected equally.If the interlacing with an eccentric interlacing axis and / or the pressure application is carried out asymmetrically, it is possible to influence the edges of the roll gap independently of one another and the quarter points independently of one another, to decouple the influence on the geometry of the roll gap at the edges, the quarter points, and in the center, and thus to contribute an asymmetrical contribution to the compensation of the deflection through interlacing with an eccentric interlacing axis and / or asymmetric pressure application. Compensating the deflection by means of interlacing and axial displacement at the edge regions of the calendered fabric is particularly advantageous. These edge regions can be the edge regions of the calendered fabric on the outside of the roll gap.However, especially when calendering electrodes, it is also common for the sheet to be calendered not to be coated across its entire width, but rather for longitudinal stripes to be provided on the sheet that are not coated. Longitudinal stripes can be arranged on the outside - relative to the roll gap - i.e. only bordering on one side to an area with a coating to be calendered. Alternatively or additionally, longitudinal stripes can be arranged on the inside - also relative to the roll gap - i.e. both sides bordering on an area with a coating to be calendered. These uncoated areas can, for example, be used to manufacture electrode contacts in a later production step. The longitudinal stripes extend transversely to the web path, i.e. along the roll gap, and their main direction of extension is along the web path, i.e. transversely to the roll gap.When calendering such a fabric with longitudinal stripes, the rollers are not in contact with the fabric in the area of ​​the longitudinal stripes, which means that edge regions of the calendered fabric are effectively also located along the longitudinal stripes. During calendering, the rollers are flattened in the areas where they are in direct contact with the calendered fabric by the force applied to the fabric. This flattening is similar to Hertzian pressure, with the difference that in the Hertzian pressure theory, no fabric is arranged between the cylinders considered there. Outside the area of ​​the rollers that is in contact with the fabric, no force is applied to the fabric.In a transition area between the flattening similar to Hertzian pressure and an area beyond the edge of the sheet that is not affected by this, the difference between the flattened and non-flattened shape of the rollers leads to shear stresses in the rollers. As a result, the roller gap narrows towards the edge area and the line force increases in the direction of the edge area. Without internally arranged longitudinal stripes, but for example with externally arranged longitudinal stripes, compensation of the effect described here is possible solely by profiles that have a 0.5 S shape. If the sheet has the described longitudinal stripes, the axial displacement of the rollers with corresponding profiles can be used to specifically compensate for the portion of the deflection caused by shear stresses due to flattening of the rollers at the edge areas of the sheet.In the case of two longitudinal stripes, i.e. three coated areas on the fabric, a 2.5 S-shape of the profiles would be necessary, for example. Since the rollers do not come into contact with the fabric in the area of ​​the longitudinal stripes, it is possible to provide a profile section here whose shape is not restricted by the need to be suitable for calendering. For example, very steep profile gradients up to discontinuities can be provided. These areas not suitable for calendering are not part of the S-shapes and polynomial descriptions of the profiles within the meaning of the present invention. If, for example, discontinuities are provided in areas of the longitudinal stripes, for example to compensate for the height of the profile gradients, the profiles within the meaning of the present invention can be represented using S-shapes and / or polynomials, omitting the discontinuities, as already described above.The jumps are accompanied by very steep areas that are at least functionally similar.

[0031] It should be expressly emphasized that the design of the profiles can influence the number and location of the areas where the roll gap is influenced. The possibilities in the design of the profiles, the possibilities of interlacing with an eccentrically arranged interlacing axis, and the asymmetrical pressure application thus provide a degree of freedom in influencing the geometry of the roll gap, which enables excellent results, especially when calendering electrodes.

[0032] It should be noted that the calender can be operated in pressure and gap mode. The details presented throughout the disclosure relate to both pressure and gap mode. In pressure mode, the calender is operated such that a uniform pressure is set in the roll gap. In gap mode, the calender is operated such that a desired gap height is set and readjusted, wherein in gap mode, as in pressure mode, pressure is applied to the main bearings. According to a further preferred embodiment of the present invention, it is provided that the displacement of the first roll along the first axial direction is accompanied by a displacement of first roll necks of the first roll by first main bearings of the calender.In other words, at least parts of the first main bearings remain fixed during the displacement of the rolls along the axial direction. In particular, it is also provided that the displacement of the second roll along the second axial direction is accompanied by a displacement of the second roll neck of the second roll by the second main bearing of the calender.

[0033] For this purpose, it is preferably provided that the first main bearings comprise cylindrical roller bearings, wherein the displacement of the first roller along the first axial direction causes a displacement of an inner ring of the first main bearing. In particular, it is provided that rolling elements and / or an outer ring of the first main bearing are not displaced when the first roller is displaced along the first axial direction. In this case, for example, the first axial adjusting means can cause the displacement of the first roll neck.

[0034] It is also conceivable for the second main bearings to comprise cylindrical roller bearings, wherein the displacement of the second roller along the second axial direction causes a displacement of an inner ring of the second main bearing. In particular, it is provided that rolling elements and / or an outer ring of the second main bearing are not displaced when the second roller is displaced along the second axial direction. In this case, for example, the second axial adjusting means can cause the displacement of the second roll neck.

[0035] It is conceivable that the rolling elements of at least one of the first main bearings and / or the second main bearings are guided only on the respective outer ring. As a result, the rolling elements would not move. It is also conceivable that the rolling elements of at least one of the first main bearings and / or the second main bearings are guided only on the respective inner ring. As a result, the rolling elements would move. Furthermore, it is conceivable that the inner ring of at least one of the first main bearings or second main bearings is formed by the first roll neck. For this purpose, the first roll neck is preferably hardened in the region of the respective bearing.

[0036] According to a further preferred embodiment of the present invention, the calender is provided with a first axial adjusting means for displacing the first roll along the axial direction. It is conceivable that the first axial adjusting means comprises a first annular cylinder. This advantageously ensures that the axial force required for this purpose acts centrally during displacement along the axial direction. A corresponding axial bearing is thus evenly loaded, which further leads to even loading of the roll. Finally, the centric application of the axial force and the resulting even loading prevent any unwanted influence on the bending line, i.e. the geometry of the roll gap.

[0037] According to a further preferred embodiment of the present invention, the first annular cylinder comprises a first expansion chamber, which is intended to be filled with an expansion medium, preferably with hydraulic oil. This advantageously makes it possible to move the first annular cylinder by introducing the expansion medium. The use of hydraulic oil is particularly advantageous because hydraulic oil, as a liquid, is virtually incompressible, and the expansion path of the first expansion chamber is thus highly defined.

[0038] It is preferably provided that the first expansion chamber is closed off by a stationary first part and a first annular piston that is movable along the axial direction. By introducing the expansion medium, the first expansion chamber is enlarged along the axial direction. In this case, the first annular piston is displaced along the axial direction. The use of a stationary first part and the first annular piston, which is movable in a defined manner along the axial direction, allows the introduction of the expansion medium into the first expansion chamber to be converted very precisely into a movement of the first axial actuating means. It is preferably provided that the stationary first part and the first annular piston each have an L-shaped part with respect to a sectional plane in which the axial direction lies.One leg of the L-shaped part of the movable first part can be displaced along one leg of the L-shaped part of the first annular piston. The first expansion chamber formed between the L-shaped parts is preferably sealed to the outside with seals.

[0039] For this purpose, it is preferably provided that the first annular piston is operatively connected to the first roller, in particular to one of the first roll necks, in order to absorb axially acting forces. In other words, axially acting forces are transmitted from the first annular piston to the first roller, in particular to one of the first roll necks. This advantageously makes it possible for a movement of the first annular piston to be directly converted into a movement of the first roller. It is preferably provided that the first annular piston is mounted on the first roll neck via a first axial bearing. In particular, it is provided that the first axial bearing is a rolling bearing, particularly preferably an axial cylindrical roller bearing. This enables smooth running of the first roller.

[0040] According to a further preferred embodiment of the present invention, the calender comprises a further first axial adjusting means for displacing the first roll counter to the axial direction. The further first axial adjusting means comprises a further first annular cylinder, wherein the further first annular cylinder preferably comprises a further first expansion chamber, which is intended to be filled with the expansion agent. The expansion agent is, in particular, a hydraulic oil. This advantageously makes it possible to displace the first roll not only along the axial direction, but also counter to it, and to allow the axial force required for this to act centrally.It is also conceivable that both the first expansion chamber and the further first expansion chamber are filled under pressure, so that the axial position of the first roller can be held by the first axial adjusting means and the further first axial adjusting means.

[0041] It is conceivable that the further first axial adjusting means is arranged on the same first roll neck of the first roll on which the first axial adjusting means is also arranged. The further first expansion chamber is closed off by a further stationary first part and a further first annular piston that is movable counter to the axial direction. The further first expansion chamber is enlarged counter to the axial direction by introducing the expansion means, whereby the further first annular piston is displaced counter to the axial direction. The further first annular piston is operatively connected to the first roll neck to absorb axially acting forces. Preferably, the further first annular piston is mounted on the first roll neck via a further first axial bearing, in particular a rolling bearing. In other words, the further first axial adjusting means is arranged on the same roll neck as the first axial adjusting means.Thus, the axial adjustment of the first roller can be effected from just one side in an advantageously simple manner, enabling technical synergy effects, for example, regarding the provision of control or supply lines. It is conceivable that the first axial bearing and the second axial bearing have a common ring, over one side of which rolling elements of the first axial bearing run, and over the other side of which rolling elements of the second axial bearing run, and which is firmly connected to the roll neck along the axial direction.

[0042] Alternatively, it is provided that the further first axial adjusting means is arranged on the first roll neck of the first roll, on which the first axial adjusting means is not arranged. Both first roll necks of the first roll are located opposite one another. The further first expansion chamber is closed off by a stationary further first part and a further first annular piston that is movable counter to the axial direction. By introducing the expansion means, the further first expansion chamber is enlarged counter to the axial direction, wherein the further first annular piston is displaced counter to the axial direction. The further first annular piston is operatively connected to the first roll neck to absorb axially acting forces, wherein the further first annular piston is preferably mounted on the first roll neck via a further first axial bearing, in particular a rolling bearing.In other words, the first axial adjusting means is arranged on one side of the first roll and the further first axial adjusting means is arranged on the other side of the first roll. The embodiment described here has the advantage that the calender is constructed symmetrically, which is simpler to design and offers the possibility of designing the first axial adjusting means and the second axial adjusting means at least partially identical. Furthermore, arranging the axial adjusting means on different sides of the roll offers the advantage that the calender is less wide overall. However, it is also conceivable that the first axial adjusting means and / or the second axial adjusting means and / or the further first axial adjusting means and / or the further second axial adjusting means act on axial bearings of the main bearings. In this regard, it is conceivable that the main bearings have combined radial-axial bearings.It is conceivable that the main bearings comprise angular contact ball bearings, tapered roller bearings, and / or spherical roller bearings. It is also conceivable that the axial adjustment means effect the axial displacement of the rollers via the main bearing housings. To apply the axial force for axial displacement, the axial adjustment means can comprise, for example, spindles, pneumatic means, electric motors, and / or hydraulic means.

[0043] According to a further preferred embodiment of the present invention, the stationary first part is supported on a first main bearing counter to the axial direction. The first main bearing is intended to support the first roll neck of the first roll. The first main bearing is capable of absorbing the axially acting forces of the first axial adjusting means. This results in an advantageously simple way of fixing the stationary first part. It is conceivable that the first main bearing comprises a cylindrical roller bearing. This makes it possible to reliably absorb large forces and to securely support the rolls. The divisions of the deflection compensation described here also relate to the inventive method described further below.

[0044] According to a further preferred embodiment of the present invention, the calender comprises means for tempering the first roller and / or the second roller. The tempering means make it possible to heat or cool the first or second roller. During calendering, particularly during the calendering of electrodes, there are often optimal temperature ranges within which calendering takes place. Depending on the temperature of the sheet material entering the calender, the calendering temperature must be raised or lowered. To achieve the optimal temperature range directly in the calendering area, heat can be dissipated from the sheet material to the rollers, thus cooling the sheet material. Furthermore, heat can be transferred from the rollers to the sheet material. To generate this heat flow, a temperature difference between the sheet material and the roller surface is necessary.The heat output transferred depends on the temperature difference, which can be adjusted by tempering the first and / or the second roller, i.e. by raising or lowering the temperature of the roller surface of the first or second roller as required. To raise the temperature, the first and / or the second roller are heated, and to lower the temperature, the first and / or the second roller are cooled. It is conceivable that the first and / or the second roller are heated to introduce heat into the sheet-like structure. It is also conceivable that the first and / or the second roller are heated to dissipate heat from the sheet-like structure. This is the case, for example, if the temperature difference between the surfaces of the rollers and the sheet-like structure is so great that excessive heat would be dissipated from the sheet-like structure without heating the rollers.It is also conceivable that the first and / or second rollers are cooled to dissipate heat from the fabric. It is also conceivable that the first and / or second rollers are cooled to transfer heat from the rollers into the fabric. This is the case when the rollers are warmer than the fabric and the temperature difference is so great that it would lead to excessive heat being transferred into the fabric.

[0045] Preferably, spacing means are provided between the first main bearings of the first roll and the second main bearing of the second roll. It is conceivable that the spacing means are provided to set a defined distance between the first main bearing and the second main bearing, thereby influencing the roll gap. The spacing means can comprise, for example, spindles, wedges, or hydraulic cylinders.

[0046] Preferably, the first roller and / or the second roller of the calender are heated to raise the temperature of the respective roller surface. This makes the calender even more suitable for use in the manufacture of electrodes. The first roller and / or the second roller can, for example, be heated electrically or inductively via induction coils. However, it is also conceivable for the first and / or the second roller to be heated with steam, which is guided, for example, through a central bore or through peripheral bores. It is preferred that the first roller and / or the second roller are provided for heating with an oil which flows through the first or second roller via peripheral bores. The roller surfaces of the first roller and / or the second roller are preferably heated to at least 80°C and very particularly preferably to at least 100°C.It is also conceivable that electrical heating elements are provided, for example in peripheral bores of the first and / or second rollers, for heating the roller surface of the first roller and / or the second roller.

[0047] Preferably, the first roller and / or the second roller of the calender are cooled to lower the temperature of the respective roller surface. This makes the calender even more suitable for use in the production of electrodes that must be calendered within a specific temperature range. If the sheet to be calendered is fed in at a temperature above the temperature range, the temperature can be lowered to the optimal range via the cooled rollers.

[0048] The first roller and / or the second roller can be cooled, for example, with a coolant which is preferably guided through a central bore or through peripheral bores.

[0049] According to a further preferred embodiment of the present invention, a region is provided in the roll nip through which the sheet to be calendered is guided and calendered, and which is also referred to as the calendering region in the context of this disclosure. Furthermore, it is provided that the calender has means for cooling the roll surface of the first roll and / or means for cooling the roll surface of the second roll, which act on the rolls, preferably from outside the rolls, and cool the roll surface outside this region (here also referred to as the non-calendering region) and preferably partially within this region. The non-calendering regions also include, in particular, regions in which the longitudinal strips described above pass through the roll nip.In addition to heat dissipation through the air, the roller surfaces of the heated rollers dissipate heat to the calendered fabric, while the roller surfaces of the heated rollers to the left and right of the calendering areas only dissipate heat to the air. This effect is further amplified with rollers heated by means of peripheral bores. To the left and right of the fabric, the roller surface temperature can be significantly higher than in the areas of the rollers that come into contact with the fabric due to a deflection of the heating medium arranged in this area of ​​the roller. This can therefore lead to undesirable changes in the roller geometry, particularly at the edge areas of the fabric, and thus to an undesirable influence on the roller gap and, consequently, to a falsification of the line force.In order to prevent the areas of the rollers that do not come into contact with the fabric from expanding so much due to excessive heating that this leads to undesirable effects in the roller nip, even to the point of contact between the first roller and the second roller outside the area through which the fabric is passed, the cooling means cool the heated rollers in these critical areas. Furthermore, the cooling ensures that the temperature profile in the roller nip is constant, and that in particular the rollers in the edge areas of the fabric are not hotter than in the middle of the roller nip. The axial displacement of the rollers relative to one another further increases the temperature gradient and the associated negative effects. The part of a roller that extends further beyond the fabric to be calendered heats up more.This is due to the fact that the area of ​​the roller into which heat is introduced but not absorbed by the fabric is larger here than on the opposite side. The part of the roller that protrudes less gets less hot. In particular, this also creates a temperature difference between the first roller and the second roller at points opposite each other in the roller gap. To prevent unwanted influences on the geometry of the roller gap, it is preferably provided that the cooling means can be adjusted independently of one another in terms of their respective cooling performance and, in particular, can be operated asymmetrically. This allows the problem described to be addressed directly and cooling can be provided as needed. Furthermore, it is conceivable that the cooling means can each be moved independently of one another along the axial direction.This allows the cooling means to be individually and precisely positioned at the points where heat needs to be dissipated from the rollers. Finally, it is conceivable that by varying the cooling intensity, for example, by cooling both sides of a roller to different degrees and / or by cooling the first and second rollers differently, the temperature distribution of the rollers and thus also the geometry of the roller gap can be specifically influenced.

[0050] It is also conceivable for the calender to have means for heating the roll surface of the first roll and / or means for heating the roll surface of the second roll, which act on the rolls, preferably from outside the rolls, and heat the roll surface in the non-calendering region and preferably partially within the calendering region. The non-calendering regions also include, in particular, regions in which the longitudinal strips described above pass through the roll gap. Cooled rolls absorb heat from the air as well as the calendered fabric, while the roll surfaces of the cooled rolls to the left and right of the calendering regions only absorb heat from the air. This effect is further enhanced with rolls cooled by means of peripheral bores.To the left and right of the fabric, the roller surface temperature can be significantly lower than in the areas of the rollers that come into contact with the fabric due to a coolant deflection arranged in this area of ​​the roller. This can lead to undesirable changes in the roller geometry, particularly at the edge areas of the fabric, and thus to an undesirable influence on the roller gap and, consequently, to a distortion of the line force. To prevent the areas of the rollers that do not come into contact with the fabric from becoming so severely deformed by greater cooling that unwanted effects occur in the roller gap, the heating means heat the cooled rollers in these critical areas.Furthermore, the heating ensures that the temperature profile in the roll nip is constant, and that in particular the rolls in the edge areas of the fabric are not cooler than, for example, in the middle of the roll nip. The axial displacement of the rolls relative to one another further intensifies the temperature gradient and the associated negative effects. The part of a roll that extends further beyond the fabric to be calendered cools down more quickly. This is because the area of ​​the roll from which heat is taken but not introduced by the fabric is larger here than on the opposite side. The part of the roll that extends less far gets less cold. In particular, this also creates a temperature difference between the first and second rolls at points opposite each other in the roll nip.In order to prevent unwanted influences on the geometry of the roll gap, it is preferably provided that the heating means can be adjusted independently of one another in terms of their respective heating output and, in particular, can be operated asymmetrically. This allows the problem described to be addressed directly and reheated as needed. Furthermore, it is conceivable that the heating means can each be moved independently of one another along the axial direction. This allows the heating means to be individually and precisely positioned at the points where heat must be dissipated from the rolls. Finally, it is conceivable that the temperature distribution of the rolls and thus also the geometry of the roll gap can be specifically influenced by heating to different intensities, for example by heating both sides of a roll to different intensities and / or by heating the first and second rolls differently.It is conceivable, for example, that the heating means are intended for inductive heating of the roller surfaces.

[0051] According to a further preferred embodiment of the present invention, the first profile is introduced by grinding the surface of the first roll, wherein the first roll is heated during grinding to the temperature intended for operation of the first roll. This makes it possible to achieve an extremely high accuracy of the first profile during operation of the calender. Temperature-related changes in the roll geometry can thus be at least partially compensated for. It is also conceivable that the second profile is introduced by grinding the surface of the second roll, wherein the second roll is heated during grinding to the temperature intended for operation of the second roll. In particular, the hot grinding described here can compensate for a polygon effect that occurs when the first roll is heated by means of peripheral bores.The temperature gradient of the roll between locations near the peripheral bores and locations farther away from the peripheral bores leads to different heat-induced expansions of the roll barrel, which forms the calendering area. Hot grinding makes it possible to grind the roll such that the different heat-induced expansions during operation of the ground roll lead to the desired peripheral shape and, in particular, to the avoidance of the polygon effect. It is particularly preferred that the surfaces of the roll barrels of the first roll and / or the second roll are hard-chrome-plated. It is also conceivable that the surfaces of the roll barrels of the first roll and / or the second roll are tungsten carbide coated. Furthermore, it is preferably additionally or alternatively provided that the surfaces of the roll barrels of the first roll and / or the second roll are inductively surface-hardened.

[0052] A further object for achieving the object posed at the outset is a method for operating a calender, in particular a calender according to the invention, wherein a deflection of the first roll of the calender is compensated by displacing the first roll along the first axial direction and / or the second roll along the second axial direction and by interlacing the rolls such that the roll gap has a desired and in particular uniform gap height. The method according to the invention advantageously enables sheet materials, for example in the production of electrodes, to be calendered with high precision using very high line forces across a wide web width. Even with web widths of significantly more than one meter, the gap height can be adjusted across the entire web width with an accuracy of 1 pm or less, and at the same time, calendering can be carried out using line forces of up to 10,000 N / mm.

[0053] According to a further preferred embodiment of the present invention, in addition to the deflection, temperature-induced deformations of the first roll and / or the second roll of the calender are compensated for by shifting the rolls along the axial direction and interlacing them such that the roll gap has the desired gap height profile along the axial direction. In particular, it can be provided that shifting the rolls along the axial direction and interlacing them compensates for deformations of the rolls caused by locally different temperatures of the rolls and thus locally different thermal expansion of the rolls. The features, details, and advantages previously mentioned in connection with the calender according to the invention likewise relate to the method according to the invention.

[0054] Further details, features, and advantages of the invention will become apparent from the drawings and the following description of preferred embodiments with reference to the drawings. The drawings merely illustrate exemplary embodiments of the invention, which do not limit the scope of the invention.

[0055] They show:

[0056] Fig. 1 : a schematic view of a calender according to an exemplary embodiment of the present invention for carrying out a method according to an exemplary embodiment of the present invention,

[0057] Fig. 2: a schematic view of the working rolls of a calender according to another exemplary embodiment of the present invention for carrying out a method according to an exemplary embodiment of the present invention,

[0058] Fig. 3: schematic views of the first roller and the second

[0059] Roll of a calender according to an exemplary embodiment of the present invention in different relative positions along the axial direction,

[0060] Fig. 4 (a) to (d): schematic views of a main bearing of a calender according to an exemplary embodiment of the present invention,

[0061] Fig. 5. a schematic view of a calender according to an exemplary embodiment of the present invention for carrying out a method according to an exemplary embodiment of the present invention in an unloaded state,

[0062] Fig. 6 is a schematic view of a calender according to another exemplary embodiment of the present invention for carrying out a method according to an exemplary embodiment of the present invention in an unloaded state,

[0063] Fig. 7: a schematic view of a detail of a calender according to another exemplary embodiment of the present invention,

[0064] Fig. 8 is a schematic view of a detail of a calender according to another exemplary embodiment of the present invention,

[0065] Fig. 9 (a) and (b) Detailed views of a calender from the prior art and

[0066] Fig. 10 (a)-(c) Detailed views of calenders according to different exemplary embodiments of the present invention.

[0067] Figures 1, 5 and 6 show calenders 100 according to exemplary embodiments of the present invention in a side view (Figure 1) and in a view along the fabric direction W (Figures 5 and 6). The opposite side of the calender 100 shown in Figure 1 is constructed as a mirror image of the side shown. The calender 100 is intended for calendering sheet material 10, in particular for producing electrodes. For this purpose, the calender 100 has a first roller 1 and a second roller 2, which can be heated, for example, with an oil that flows through peripheral bores of the rollers 1, 2 (not shown for the sake of clarity). The first roller 1 is mounted in a calender frame 20 so as to be rotatable about a first axial direction A1. The second roller 2 is mounted in the calender frame 20 so as to be rotatable about a second axial direction A2. It is conceivable that the calender 100 has additional rollers.In the following, however, the description will be limited to the first roll 1 and the second roll 2, which form the working rolls of the illustrated embodiments. A roll gap 9 is formed between the first roll 1 and the second roll 2, into which the fabric is fed in the fabric direction W.

[0068] The first roll 1 is supported by first roll necks 3 in first main bearings 5 ​​(see Figs. 4, 7, and 8). The second roll 2 is supported by second roll necks 4 in second main bearings. The first main bearings 5 ​​can comprise, for example, rolling bearings, in particular cylindrical roller bearings. The second main bearings are not shown here, as they are designed analogously to the first main bearings 5.

[0069] During the calendering of electrodes, a coated, conductive foil is rolled to a thickness of 40 μm to 400 μm using line forces ranging from 500 N / millimeter to 10,000 N / millimeter. Accuracy plays a key role in the electrode's subsequent performance. For example, the porosity of the electrode is determined by calendering. Even gap height deviations of 2 μm to 3 μm result in inaccuracies in the electrode manufacturing process that are barely acceptable. The calender 100 according to the invention and the method according to the invention enable the compensation of unwanted deflection with deviations of 1 μm or better.

[0070] If the coated films are calendered between the first roller 1 and the second roller 2, deformation of the rollers 1, 2 inevitably occurs. The rollers 1, 2 bend. The rollers 1, 2 also deform due to temperature differences that occur along the rollers. Temperature inhomogeneities of just a few degrees Celsius can lead to deviations in the gap height, which should be avoided. During calendering, particularly with larger web widths, this leads to deviations in the gap height that can no longer be tolerated. In order to compensate for these deviations and achieve a desired, in particular uniform, gap height, the calender 100 has an interlacing means 7 with which the first and second rollers 1, 2 can be interlaced about an interlacing axis V. The interlacing axis V is perpendicular to the first axial direction A1 of the first roller 1 and the second axial direction A2 of the second roller 2.Such an interlacing by an interlacing angle y is shown in Fig. 2. The interlacing axis V can be central, or in other words: centric, of one or both rollers 1, 2, or it can be arranged off-center, or in other words: eccentric. In Fig. 2, the interlacing axis V is arranged centrally at the top and the interlacing axis V is arranged off-center at the bottom. The interlacing by an interlacing angle y that is greater than zero, i.e. a non-parallel arrangement of the first axial direction A1 and the second axial direction A2 to one another, results in the roller gap 9 being larger further away from the interlacing axis V than near the interlacing axis V. In the example shown at the top of Fig. 2, the distance between the rollers 1, 2 is greater at the ends of the rollers 1, 2 than in the middle of the rollers 1, 2.This allows the roller gap to be adjusted variably across the width of the rollers 1, 2 to compensate for deflection of the rollers 1, 2.

[0071] To interlace the rolls 1, 2, the calender 100 is equipped with an interlacing means 7, with which one of the rolls 1, 2 or both rolls 1, 2 can be displaced relative to the calender frame 20 with a directional component perpendicular to the respective axial direction A1, A2 and can be rotated about the interlacing axis V. The interlacing can be brought about, for example, by displacing one or more main bearings. Thus, in Fig. 2 below, an interlacing can be seen in which only the first main bearing 5 (not shown) on the right-hand first roll neck 3 has been displaced upwards along the plane of the sheet. The second roll 2 has not been displaced here. In Fig. 2 above, both the first roll 1 and the second roll 2 are rotated about the interlacing axis V, which was brought about by displacing all main bearings of the rolls 1, 2.

[0072] In order to be able to adjust the compensation for unwanted deviations in the gap height with better spatial resolution and in particular to compensate for unwanted deviations introduced by the interlacing, such as overcompensation, the first roll 1 is provided with a first profile PI and the second roll 2 is provided with a second profile P2. The profiles Pl, P2 are ground into the roll barrels of the respective rolls 1, 2 and are shaped in such a way that different roll diameters are achieved along the axial direction A. The illustrations in Figs. 2 and 3 show the profiles Pl, P2 greatly enlarged. It is preferably provided that the profiles Pl, P2 are hot ground, i.e. that when the profiles Pl, P2 are ground, the respective roll is heated to a temperature which corresponds to the temperature at which it is to be operated in the calender 100.

[0073] In the embodiment shown here, the profiles Pl, P2 have different gradients and display three inflection points. By moving the first roller 1 and / or the second roller 2 relative to one another along the first axial direction A1 and / or the second axial direction A2, the profile of the height of the roller gap 9 can be adjusted. This is shown in Figure 3. In Figure 3, the first roller 1 and the second roller 2 can be seen in three different relative positions. In the relative position shown at the top, the profiles Pl, P2 run parallel to one another without load, i.e. without calendering a sheet-like structure 10. As soon as a sheet-like structure 10 is calendered, this changes due to the force introduced which occurs when the sheet-like structure 10 is rolled. To compensate for this, the first roller 1 and the second roller 2 can be moved relative to one another.

[0074] The setting of a desired roll gap 9 with the compensation of the deflection is therefore achieved through a combination of interlacing and axial displacement. It is conceivable that the deflection is fully compensated by interlacing the first roll 1 and the second roll 2, and that the resulting overcompensation at the quarter points is balanced out by shifting the rolls 1, 2 against each other along the axial direction A. For this purpose, the first profile PI and the second profile P2 each have a double S shape in the form of a fifth-degree polynomial. Another possibility for setting a desired roll gap 9 is that the deflection is only partially compensated, for example by 2 / 3, by interlacing the first roll 1 and the second roll 1, and the remaining compensation is achieved by shifting along the axial direction A.For this purpose, profiles Pl, P2 would be provided, which only have an S-shape in the form of a third-degree polynomial.

[0075] Furthermore, it is also possible to specifically influence the quarter points through axial displacement. For this purpose, the deflection compensation components, which are due partly to axial displacement and partly to twisting, can be varied. Such combinations could include superimposing the S-shape with a double S-shape of the first profile PI and superimposing the S-shape with a double S-shape of the second profile P2, with the first profile PI and the second profile P2 having the shape of a fifth-degree polynomial.

[0076] Overall, the combination of symmetrical pressure application in the main bearings 5, 6 with axial displacement and offsetting results in a very flexible option for setting the desired roll gap 9. In addition, it is also possible to influence the roll gap 9 through asymmetrical pressure application. For this purpose, for example, different amounts of force can be applied to the opposite main bearings 5, 6 of a roll 1, 2. Depending on the selected distribution of the deflection compensation between the axial displacement, offsetting with a centrally or eccentrically arranged offset axis V as well as between symmetrical and asymmetrical pressure application, the zones of the roll gap 9, i.e. in particular the areas between the roll necks 3, 4 and the quarter points, the quarter points and the area between the quarter points, can be adjusted in a targeted manner and taking into account other conceivable effects of the axial displacement and offsetting.

[0077] Furthermore, it is possible to compensate for the deflection by interlacing until overcompensation is just avoided, especially at the quarter points. The remaining deflection, especially in the center of the roll gap 9, is compensated by displacement along the axial direction A. For this purpose, the profiles P1, P2 have an S-shape.

[0078] In the relative position shown in the middle, the first roller 1 is shifted to the left and the second roller 2 to the right. Shown below is a relative position in which the first roller 1 is shifted to the right and the second roller 2 to the left. The relative positions shown here clearly show how the profile of the height of the roller gap 9 changes as a result of the shifting. In particular, this can influence the areas of the roller gap 9 between the outer ends and the middle. The position of the first roller 1 and / or the second roller 2 along the axial direction A is preferably monitored and readjusted if there is a deviation from a target value.

[0079] Figures 4 (a) to (d) each show a section of a calender 100, in which one of the first main bearings 5 ​​can be seen. The first main bearing 5 is designed here as a cylindrical roller bearing with an outer ring 5.1, an inner ring 5.2 and rolling elements 5.3. In the embodiments shown in Figs. 4 (a) and (b), the rolling elements 5.3 are laterally guided by a rolling element guide 5.4, which is connected to the outer ring 5.1. When the roll neck 3 is displaced along the first axial direction A1 by a first axial adjusting element (not shown here), the inner ring 5.2 is displaced along with it, the rolling elements

[0080] 5.3 are held in position by the rolling element guide 5.4, however, relative to the first axial direction Al and are fixed to the outer ring 5.1. Fig. 5 (c) shows an exemplary embodiment in which the rolling element guide

[0081] 5.4 is fastened to the inner ring 5.2. With a displacement of the inner ring 5.2 along the first axial direction Al, the rolling elements 5.3 are also displaced. Fig. 5 (d) shows an exemplary embodiment in which the inner ring 5.2 is formed by the roll neck 3 itself. For this purpose, the roll neck 3 is surface hardened. The rolling element guide 5.4 is again fastened to the outer ring 5.1, as a result of which the rolling elements 5.4 are not displaced in the first axial direction Al. The details of the first main bearing 5 shown here also apply to the second main bearings, whose inner rings are displaced with or without rolling elements.

[0082] What the embodiments shown have in common is that they have a first axial adjusting means 13, which is shown in detail in Figures 7 and 8 according to different embodiments of the present invention. The first axial adjusting means 13 is provided to displace the first roll 1 along the axial direction A. For this purpose, the first axial adjusting means 13 has a first annular cylinder 31. The first annular cylinder 31 has a first expansion chamber 32, which can be filled with an expansion medium, for example with hydraulic oil. The first annular cylinder 31 is arranged along the entire circumference of the first roll neck 3 of the first roll 1. By introducing the expansion medium into the first expansion chamber 32, a first annular piston 34 is displaced along the axial direction A.The first annular piston 34 presses in the axial direction A against a first axial bearing 35, which here is designed in the form of a rolling bearing, against whose ring on the roll barrel side the first annular piston 34 rests. The ring of the first axial bearing 35 facing away from the roll barrel is firmly connected to the first roll neck 3. Thus, a movement of the first annular piston 34 along the axial direction A leads to a movement of the first roll neck 3 along the axial direction A. The arrangement of the first expansion chamber 32 along the entire circumference of the first roll neck 5 enables a centric application of the axial force for displacing the first roll 1 along the axial direction A, resulting in a uniform load on the first axial bearing 35 and thus a uniform load on the first roll 1. Furthermore, an undesirable influence on the roll gap 9 due to a non-centric application of the axial force is avoided.

[0083] Figure 7 shows that the stationary first part 33 is supported on the first main bearing 5 opposite to the axial direction A. The first expansion chamber 32 is formed by a gap between the stationary first part 33 and the first annular piston 34. To prevent leaks through which the expansion medium could escape, the first expansion chamber 32 is sealed with circumferential seals 36.

[0084] In the exemplary embodiment shown in Figure 7, the first axial adjusting means 13 is arranged on the side of the main bearing 5 facing away from the roll barrel. However, it is also conceivable that the first axial adjusting means 13 is arranged on the side of the main bearing 5 facing the roll barrel. Not visible is the further first axial adjusting means 13', which in the exemplary embodiment shown in Figure 7 is located on the opposite side of the first roll 1 on the other first roll neck 3 and can cause a displacement of the first roll 1 counter to the axial direction A. According to this exemplary embodiment, the further first axial adjusting means 13' is designed to be completely mirror-symmetrical to the first axial adjusting means 13, which is why a pictorial representation is omitted here.In contrast to the exemplary embodiment shown in Figure 7, in the exemplary embodiment shown in Figure 8, both the first axial adjusting means 13 and the further first axial adjusting means 13' are arranged on the same first roll neck 3 of the first roll 1. Both the first axial adjusting means 13 and the further first axial adjusting means 13' are arranged here on the side of the main bearing 5 facing away from the roll barrel. However, it is also conceivable that the first axial adjusting means 13 and the further first axial adjusting means 13' are arranged on the side of the main bearing 5 facing the roll barrel. The fixed first part 33 of the first axial adjusting means 13 is supported on the first main bearing 5 opposite to the axial direction A.Furthermore, the stationary first part 33 forms a side wall of the first expansion chamber 32 as well as an upper wall of the expansion chamber 32 and an upper wall of the wide expansion chamber 32' of the further first axial actuating means 13'. The stationary first part 33 thus spans the first axial actuating means 13 and, at least partially, also the further first axial actuating means 13'. In addition to the first expansion chamber 32 of the first axial actuating means 13, the further first expansion chamber 32' of the further first axial actuating means 13' can also be seen. Like the first expansion chamber 32, the further first expansion chamber 32' is intended to be filled with the expansion medium. When the expansion medium is introduced into the further first expansion chamber 32', a movable further first annular piston 34' of the further first axial actuating means 3' moves counter to the axial direction A.Here, the further first annular piston 34' presses against the axial direction A against a further first axial bearing 35', whose roll barrel-side ring is firmly connected to the first roll neck 5. Filling the further first expansion chamber 32' thereby causes the first roll 1 to move against the axial direction A. The roll barrel-side ring of the further first axial bearing 35' and the ring of the first axial bearing 35, which faces away from the roll barrel of the first roll 1, are integrally connected to one another. However, it is also conceivable that these rings are separate.

[0085] Not shown are the details of the second axial adjusting means 14 and the further second axial adjusting means 14', which correspond completely to the details of the first axial adjusting means 13 and the further first axial adjusting means 13' shown here and have a second or further second annular cylinder with a second expansion chamber or further second expansion chamber, which is formed between a stationary second part and a movable second annular piston or between a stationary further second part and a movable further second annular piston. The movable second part of the second axial adjusting means 14 is supported on a second axial bearing. The movable further second part of the further second axial adjusting means 14' is supported on a further second axial bearing.

[0086] The axial position of the first roller 1 and the second roller 2 is controlled servo-hydraulically. For this purpose, the axial positions of the first roller 1 and the second roller 2 are measured, and the pressures in the expansion chambers 32, 32' are regulated so that the axial positions correspond to target values.

[0087] The rollers 1, 2 are temperature-controlled, particularly for calendering electrodes. For this purpose, the rollers 1, 2 are heated, for example, by means of peripheral bores (not shown) in which a heating medium is arranged or passed. The heating medium can be, for example, oil, steam, or the like. It is also conceivable for electrical heating elements to be provided in the peripheral bores or for the rollers 1, 2 to be heated inductively. The heat introduced by the heating is, on the one hand, dissipated by the roller surfaces into the ambient air, but, on the other hand, is also absorbed by the calendered sheet material 10. This results in a temperature gradient on the rollers 1, 2 between an area in which the roller surfaces of the rollers 1, 2 come into contact with the sheet material 10, the so-called calendering areas 92, and the areas to the left and right of these areas, the so-called non-calendering areas 93.This temperature gradient can be further increased by diverting the peripheral bores at the outer ends of the roll barrels in 180° turns, thus allowing more heat to be transferred from the heating medium to the rolls 1, 2. Due to the different thermal expansions of the rolls 1, 2 along the axial direction A, the temperature gradient influences the geometry of the rolls 1, 2 and thus also the geometry of the roll gap 9 and the bending line, and can lead to undesirable effects, such as a deviation from the intended geometry of the roll gap 9, or even contact between the first roll 1 and the second roll 2 outside the area in which the sheet 10 is calendered. To prevent this, means for cooling 15 of the first roller 1 and the second roller 2 are provided outside the rollers 1, 2, as can be seen in Figures 1, 2, 3 and 5.The cooling means 15 are arranged such that they absorb heat from the roller surfaces of the rollers 1, 2 in the areas that do not come into contact with the sheet material 10 and simultaneously also absorb heat from the areas of the roller surface of the rollers 1, 2 that come into direct contact with the sheet material 10. For this purpose, the cooling means 15 can be displaced along the axial direction A. The heat absorption by the cooling means 15 makes it possible to even out the temperature of the roller surfaces of the rollers 1, 2 along the roller gap 9 and thus prevent undesirable effects caused by temperature gradients. Cooling even makes it possible to specifically influence the thermal expansion of the rollers 1, 2 and actively change the geometry of the roller gap 9.

[0088] It is also conceivable, however, that the rolls 1, 2 are cooled. This is particularly advantageous if the sheet 10 is fed to the calender 100 at a temperature which is above the optimal temperature for calendering the sheet 10. The cooling can be effected, for example, by means of peripheral bores (not shown) in which a coolant is arranged or passed through. The heat dissipated by the cooling is partially re-introduced into the rolls 1, 2 by the calendered sheet 10 during calendering. This results in a temperature gradient on the rolls 1, 2 between the calendering regions 92 and the non-calendering regions 93. The temperature gradient can be further increased by diverting the peripheral bores for cooling at the outer ends of the roll barrels in 180° turns, so that more heat can be absorbed by the coolant there.Due to the different thermal expansions of the rollers 1, 2 along the axial direction A, the temperature gradient influences the geometry of the rollers 1, 2 and thus also the geometry of the roller gap 9 and the bending line, and can lead to undesirable effects, such as a deviation from the intended geometry of the roller gap 9. To prevent this, means for heating the first roller 1 and the second roller 2 (not shown, analogous to reference numeral 15) are provided outside the rollers 1, 2. The heating means are arranged in such a way that they introduce heat from the roller surfaces of the rollers 1, 2 into the areas that do not come into contact with the sheet material 10 and, at the same time, also introduce heat into the area of ​​the roller surface of the rollers 1, 2 that comes into direct contact with the sheet material 10. For this purpose, the heating means can be moved along the axial direction A.By adding heat through the heating means, it is possible to even out the temperature of the roller surfaces of the rollers 1, 2 along the roller gap 9, thus preventing undesirable effects caused by temperature gradients. Heating even makes it possible to specifically influence the thermal expansion of the rollers 1, 2 and actively change the geometry of the roller gap 9. It is conceivable that the heating means are inductive heating means.

[0089] Figures 9 (a) and (b) depict an effect that occurs during calendering at the edge regions 95 of the calendered fabric 10. In the calendering region 92 of the rollers 1, 2, i.e., the region of the rollers 1, 2 that is in direct contact with the fabric 10 during calendering, the rollers 1, 2 are flattened by the application of force. Further out to the left and right of the calendering regions 92, in non-calendering regions 93, no flattening occurs due to the application of force. This difference leads to shear stresses in the rolls 1, 2. As a result, the roll gap 9 narrows in a transition region 94 between the calendering region 92 and the non-calendering region 93 towards the edge region 95 and there is an increase in the line force 91 (shown here as arrows) in the direction of the edge region 95.

[0090] The described effect occurs not only at the left and right edges of the roll gap 9. If thinner regions are provided in the sheet 10, for example, regions without a coating, non-calendering regions 93 are also present in these regions. Figures 10 (b) and (c) show a sheet 10 with three such regions, which appear as longitudinal stripes on the sheet 10. Shear stresses and thus deformations of the rolls 1, 2 also occur in the edge regions 95 of the sheet 10, which border the longitudinal stripes.

[0091] Without longitudinal stripes in the fabric 10, compensation for the effect described here is possible solely by profiles P1, P2, which have a 0.5 S shape. This is illustrated in Figure 10 (a). By axially displacing the rolls 1, 2 with the illustrated profiles P1, P2, the narrowing of the roll gap 9 in the transition region 94 between the calendering region 92 and the non-calendering region 93, caused by the flattening, can be compensated.

[0092] If the sheet material 10 has the described longitudinal stripes, the portion of the deflection caused by shear stresses due to flattening of the rollers 1, 2 at the edge regions 95 of the sheet material 10 can be specifically compensated for by axially shifting the rollers 1, 2 with corresponding profiles P1, P2. This is illustrated by way of example in Figures 10 (b) and (c). The sheet material 10 illustrated in Figure 10 (b) has three coated regions and thus (in addition to the uncoated regions of the sheet material 10 at its outer edges) two longitudinal stripes. To compensate for the effect caused by the shear stresses, a 2.5-S shape of the profiles P1, P2 is provided here. The special shape of the profiles P1, P2 in the exemplary embodiment in Figure 10 (b) results in the coated regions being offset from one another along the direction of the line force.

[0093] This can be prevented by discontinuities 96 in the profiles P1, P2, as shown in Figure 10 (c). The discontinuities 96 are incorporated into the profiles P1, P2 in the non-calendering areas 93. Here, the roll surfaces do not come into contact with the calendered fabric 10, so that the height differences between the calendering areas 92, as shown in Figure 11 (b), can be compensated. Reference symbols:

[0094] 1 first roller

[0095] 2 second roller

[0096] 3 first roll neck

[0097] 4 second roll neck

[0098] 5 first main camp

[0099] 5.1 Outer ring

[0100] 5.2 Inner ring

[0101] 5.3 Rolling elements

[0102] 5.4 Rolling element guidance

[0103] 7 Entanglement means

[0104] 9 Roller gap

[0105] 20 calender frame

[0106] 13 first axial adjusting means

[0107] 13' further first axial adjusting means

[0108] 14 second axial adjusting means

[0109] 14' further second axial adjusting means

[0110] 15 cooling remedies

[0111] 19 axial adjusting device

[0112] 31 first ring cylinder

[0113] 31' further first ring cylinder

[0114] 32 first expansion room

[0115] 32' additional first expansion space

[0116] 33 fixed first part

[0117] 33' fixed further first part

[0118] 34 first ring piston

[0119] 34' further first ring piston

[0120] 35 first thrust bearing

[0121] 35' additional first axial bearing

[0122] 36 Seal

[0123] 91 Line force

[0124] 92 calendering area

[0125] 93 non-calendering area

[0126] 94 Transition area 95 Edge area

[0127] 96 jump point

[0128] 100 calenders

[0129] Al first axial direction

[0130] A2 second axial direction

[0131] PI first profile

[0132] P2 second profile W fabric direction

[0133] Y angle of twist

Claims

Patent claims:

1. Calender (100) for calendering flat structures (10), preferably for producing electrodes, comprising a first roller (1) and a second roller (2), wherein the rollers (1, 2) can be displaced relative to one another along a first axial direction (Al) of the first roller (1) and / or along a second axial direction (A2) of the second roller (2), wherein the calender (100) has an interlacing means (7) for interlacing the first roller (1) and the second roller (2) about an interlacing axis (V), wherein the interlacing axis (V) is perpendicular to the first axial direction (Al) and the second axial direction (A2).

2. Calender (100) according to claim 1, characterized in that the first roll (1) has a first profile (PI) and the second roll (2) has a second profile (P2), wherein the first profile (PI) has a 0.5-S shape, or a multiple of a 0.5-S shape, preferably a 1.0 or 1.5-S shape, particularly preferably a double-S shape, very particularly preferably a 2.5-S shape and the second profile (P2) has a 0.5-S shape or a multiple of a 0.5-S shape, preferably a 1.0-S shape, preferably a 1.5-S shape, particularly preferably a double-S shape, very particularly preferably a 2.5-S shape.

3. Calender (100) according to one of the preceding claims, characterized in that the first profile (P1) and the second profile (P2) are designed such that in a relative position of the first and the second roll (1, 2) the roll gap (9) has a uniform gap height along the axial directions (A1, A2) when the interlacing device (7) interlaces the first and the second roll (1, 2) by an interlacing angle (y) about the interlacing axis (V).

4. Calender (100) according to one of the preceding claims, characterized in that the displacement of the first roll (1) along the first axial direction (Al) with a displacement of first Roll neck (3) of the first roll (1) is accompanied by first main bearings (5) of the calender (100).

5. Calender (100) according to claim 4, characterized in that the first main bearings (5) comprise cylindrical roller bearings, wherein the displacement of the first roller (1) along the first axial direction (Al) causes a displacement of an inner ring (5.2) of the first main bearing, wherein it is provided in particular that rolling elements (5.3) and / or an outer ring (5.1) of the first main bearing (5) are not displaced when the first roller (1) is displaced along the first axial direction (Al).

6. Calender (100) according to claim 4 or 5, characterized in that a displacement of the second roll (2) along the second axial direction (A2) is accompanied by a displacement of second roll necks (4) of the second roll (2) by second main bearings (4) of the calender (100), wherein the second main bearings (6) preferably have cylindrical roller bearings, wherein the displacement of the second roll (2) along the second axial direction (A2) particularly preferably causes a displacement of an inner ring of the second main bearing (6), wherein it is provided in particular that rolling elements and / or an outer ring of the second main bearing (6) are not displaced when the second roll (2) is displaced along the second axial direction (A2).

7. Calender (100) according to one of the preceding claims, characterized in that the first roller (1) and / or the second roller (2) are heated.

8. Method for operating a calender (100), in particular a calender (100) according to one of the preceding claims, wherein a deflection of the first roll (1) of the calender (100) is compensated by displacing the first roll (1) along the first axial direction (A1) and / or the second roll (2) along the second axial direction (A2) and by interlacing the rolls (1, 2) such that the roll gap (9) has a desired and in particular uniform gap height.

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