EP1903143A1 - Deflection adjusting roller - Google Patents

Abstract

Bending adjustment roller has a mantel support system comprising pistons (8) which press against the inner surface of the mantel (3) to adjust its curvature. The contact surface (11) of the support is also deformable.

Description

The invention relates to a deflection adjusting roll with a circumferential jacket, a non-rotatable support passing through the jacket, with at least one support shoe between the support and the jacket, the direction of action corresponds to a press direction, and at least one supporting element guided in the support between the support and the jacket , whose effective direction deviates in the direction of rotation of the jacket from the press direction and which rests with a contact surface from the inside of the jacket.

Such a deflection adjustment roller is made, for example EP 0 764 790 B1 known.

In a deflection-adjusting roller, the jacket is supported by a plurality of support shoes, which are arranged distributed in the direction of its axial extension, relative to the carrier. If the jacket rests against a counter roll, then you can make an approximation of the bending line of the shell to the bending line of the backing roll with the help of the support shoes. In order to achieve such an alignment already when the nipple is still open to the backing roll, one or more support elements are generally provided in the end regions of the roll shell, which act in a different direction. With the support elements to be achieved that the bending line of the shell can be influenced in a certain way even if no external Forces acting on the jacket, for example, a counter-roller.

The loading of the jacket by the support shoes and the support elements results in a function of the other loads to a deformation of the shell. Its cross-sectional shape then deviates from the ideal circular shape. This process is called "ovalization" for a short time.

In particular, in the area of the support elements can be observed that the jacket is pulled transversely to its axial direction in the length. The inside of the shell then has a curvature in the region of the support elements that is greater than the curvature of the roll shell in the ideal circular shape, ie. the radius of curvature is smaller. This ovalization is greater, the smaller the wall thickness of the shell. However, a small wall thickness is desired, so that the roller has a good correction behavior in the axial direction, ie the deflection can be set in the smallest possible zones. In this case, such a deflection roll in a paper calender can also be used for paper thickness profiling. The smallest possible shell wall thickness is decisively limited by the ovalization and the permissible tangential stresses in the secondary area, ie in the area of the support elements.

Due to the ovalization of the shell, it comes namely to the support elements to a so-called oil gap error, in which the gap between the inside of the shell and the contact surface of the support element to the outside narrows. Such an oil gap causes the support elements tend to "eat". He must therefore be avoided. Support elements are therefore often undercut ground to anticipate the deformation of the shell. However, the shape of the support element is then only suitable for a specific load situation. With changed loads, it may again come to an insufficient oil film between the support element and the jacket. This increases the wear even if the support element and the jacket do not eat yet.

The invention has for its object to increase the life of the roller.

This object is achieved in a deflection adjustment of the type mentioned fact that the contact surface is similar to the shell deformable.

The deformation of the shell can be determined in advance by calculation. It depends, among other things, on the material of the jacket, its geometric dimensions and the loads. Accordingly, you can also form the support member so that it deforms in the occurring loads in a similar manner as the jacket. The contact surface then deviates from the ideal circular shape of the shell in the unloaded and gravity-free state and thus adapts to the cross-sectional shape of the shell in the region of the support element. In this case, no mathematically exact match must be achieved. A change in the oil gap between the support member and the shell in the circumferential direction is not critical, as long as this change a predetermined Size does not exceed. Characterized in that the contact surface is variable, the variation of the thickness of the oil gap in the direction of rotation can be kept small.

The contact surface preferably has a pressure surface arrangement which has at least two pressure pockets in the direction of rotation at a predetermined distance. The pressure pockets are pressurized during operation with liquid under pressure, usually oil. This oil flows over the edge of the pressure pockets, so that an oil film is formed, which causes a hydrostatic streaking between the shell and the support element. The fact that now displaces the pressure pockets in the direction of rotation of the shell to the outside, creates forces on the support element, which can be used to deform the contact surface. This makes it possible to keep the oil film which forms between the contact surface and the jacket, uniform within certain limits. The term "contact surface" has been chosen here for the sake of clarity, even if the support element is not actually applied directly to the roll shell, but always an oil film between the support member and the roll shell should be present. The arrangement of the pressure pockets in the direction of rotation further out than before ensures that a torque can always act on the outer regions of the contact surface, which leads to a corresponding deformation of the contact surface. This torque is self-adjusting within certain limits. If the contact surface deforms too much, then too much oil flows over the corresponding outer edge of the pressure pocket, so that the forces acting on the outer area of the pressure pocket in the circumferential direction decrease and the deformation of the contact surface regresses again. This process continues until the shape of the contact surface has largely approximated the shape of the inside of the shell.

It is preferred that between the pressure pockets in the circumferential direction of the jacket, a zone is arranged with respect to the pressure pockets reduced pressure. Ideally, this is a pressure-free zone. The support element and thus the contact surface is thus acted upon solely by the pressure in the pressure pockets, so that the contact surface can be deformed in the direction of rotation outside of the roll shell away and so to speak can bulge in the direction of rotation inside, without this being prevented by a corresponding back pressure becomes.

Preferably, the pressure pockets are at least over part of their surface in the circumferential direction over the piston. This makes it possible to generate a share of force on the contact surface, which counteract only the material stresses as a counterforce. A support force, in the opposite direction, is absent in this area. This facilitates the deformation of the contact surface.

It is preferred that the part is at least 50% of the area. This is a relatively large proportion, so that the contact surface can be deformed sufficiently without the pressures must be too large.

Preferably, the support member has a bearing surface bearing head, wherein the ratio between the largest extent in the circumferential direction and its radial thickness at the edge in the range of 6 - 18 is located. Preferably, the ratio is above 7 and more preferably above 9. Thereby, the support member, more specifically its head, is made relatively thin in the radial direction so that the abutment surface can be easily deformed to conform to the shape of the inside of the shell. The thinner the head, the easier the deformability. However, the ratio must not be too large, so that the head of the deformation can still provide some resistance.

Preferably, the head is formed of a different material than the piston. One is then free in the design. In particular, one can dimension the piston to a good interaction with the carrier, in particular with regard to the tightness. The head, on the other hand, can be designed for the desired deformability.

It is preferred that the material of the head is easier to deform than the material of the piston. The piston should remain as dimensionally stable as possible even at higher pressure loads. This can for example be realized in that the piston is formed of steel. The head, on the other hand, can be made of bronze or brass so that it can be deformed more easily than the piston.

Preferably, at least one pressure pocket is arranged in a pressure pocket carrier which is arranged to be movable relative to the piston. When the pressure-bag carrier change its orientation relative to the piston, then the shape of the contact surface is changed. Again, this is a way to adapt the shape of the contact surface to the shape of the shell. In this case, one can easily accept that the pressure-bag carrier is not deformable in itself or only to a small extent. The pressure pad carrier has an extent in the direction of rotation of the shell, which is so small that an oil gap failure practically does not occur. Since the pressure pad carrier in the circumferential direction have a sufficient distance, one can overall ensure that the oil-filled gap between the support member and the jacket remains substantially uniform.

It is preferred that the pressure pad carrier is supported by a spring arrangement on the piston. The spring arrangement allows on the one hand a certain mobility of the pressure-box carrier relative to the piston, but on the other hand also ensures a corresponding restoring force. The pressures generated in the pressure pocket assembly must be in equilibrium with the counter forces generated by the spring assembly. In this way, the gap between the support member and the jacket can be kept uniform with little effort.

The spring arrangement preferably has at least one elastic intermediate element. This facilitates the assembly.

It is preferred that the intermediate element has a planar extension. The intermediate element can therefore be considered as a kind of flat block of an elastomeric Be formed material on which the pressure pad carrier is simply placed. If necessary, you can then attach the pressure pad carrier also on the piston to ensure a certain loss of security.

In an alternative or additional embodiment can be provided that the pressure pad carrier is connected via a hinge assembly with the piston. A joint arrangement also allows for a certain mobility between the pressure pad carrier and the piston, so that the pressure pad carrier relative to the jacket can set freely within certain limits, so that the contact surface can adapt to the shape of the shell.

Preferably, the hinge assembly has a hinge axis which is parallel to the axis of rotation of the roll mantle. This is a particularly simple embodiment. In the ovalization of the shell, although the curvature of the shell changes, but not the direction of the axis of curvature. This usually remains parallel to the axis of rotation of the roller. Accordingly, it is sufficient to be able to pivot the pressure pad carrier also about a hinge axis extending parallel to the axis of rotation.

In an alternative embodiment it can be provided that the joint arrangement has a ball joint. In this case, the pressure pad carrier can also tilt with a component in the axial direction, so that here, a certain balance is possible.

In all cases, it is advantageous if the pressure pad carrier has a contact surface with the piston, the is smaller than a cross-sectional area of the piston, wherein the piston area is smaller than a pressure-bag carrier head surface. The pressure-cup carrier head surface is basically the surface on which the hydraulic pressure acts between the support element and the casing. If this top surface is larger than the piston surface, then it is ensured that a gap is always formed here to avoid contact between the pressure pad carrier and the jacket. If you make the contact surface between the pressure pad carrier and the piston smaller than the cross-sectional area of the piston, then the pressure pad carrier is always with a sufficient pressure on the piston, so that you can achieve a safe transfer of pressure fluid from the piston into the pressure pad carrier.

Preferably, the jacket has a wall thickness which is at most 10% of its inner diameter. It is therefore a relatively thin shell, with which one can achieve a relatively fine resolution in a zone control in the axial direction. On the other hand, such a coat also tends greatly to ovalize, but this means no problem with the above-described support elements.

Fig. 1

eine stark schematisierte Darstellung einer Durchbiegungseinstellwalze mit einer Gegenwalze im Längsschnitt,

Fig. 2

die Darstellung nach Fig. 1 im Querschnitt,

Fig. 3

eine vergrößerte Darstellung eines Stützelements in Seitenansicht,

Fig. 4

das Stützelement in Draufsicht,

Fig. 5

eine schematische Darstellung zur Erläuterung der Wirkungsweise des Stützelements,

Fig. 6

eine abgewandelte Ausführungsform eines Stützelements in Seitenansicht,

Fig. 7

das Stützelement nach Fig. 6 in Draufsicht,

Fig. 8

eine dritte Ausführungsform des Stützelements in Seitenansicht und

Fig. 9

das Stützelement nach Fig. 8 in Draufsicht.

The invention will be described in more detail below with reference to preferred embodiments in conjunction with the drawings. Herein show:

Fig. 1

a highly schematic representation of a deflection adjusting roll with a counter roll in longitudinal section,

Fig. 2

the representation of FIG. 1 in cross section,

Fig. 3

an enlarged view of a support member in side view,

Fig. 4

the support element in plan view,

Fig. 5

a schematic representation for explaining the operation of the support element,

Fig. 6

a modified embodiment of a support member in side view,

Fig. 7

the support element of Fig. 6 in plan view,

Fig. 8

a third embodiment of the support member in side view and

Fig. 9

the support element of FIG. 8 in plan view.

Fig. 1 shows a highly schematic representation of a deflection adjustment roller 1, which cooperates with a counter-roller 2. The deflection adjustment roller 1 is used here as a top roller. It can also be used as a bottom roll or as one of two end rolls of a calender with several intermediate rolls.

The deflection adjustment roller 1 has a jacket 3 which is designed as a roller tube and surrounds a carrier 4. The carrier 4 is not rotatably held in a non-illustrated framing of a calender.

Between the carrier 4 and the roll shell 3 a plurality of Stutz shoes 5 are arranged, with which the roll shell 3 can be applied zonally with respect to the carrier 4 with a force. The support shoes 5 have a direction of action, which points to the counter-roller 2. This corresponds to a press direction.

In the opposite direction support elements 6, which are arranged in the region of the axial ends of the roll shell 3 act. At both ends in each case a support element 6 is arranged. Usually, however, more than one support element 6 is arranged at each end of the roll mantle 3, for example three to five support elements 6.

When the support shoes 5 and the support members 6 come into action, the roll shell 3 is deformed. Without occurrence of external forces, the roll shell 3 ideally has the shape of a hollow cylinder, ie a circular cross-section.

If the support sources 5 press the roll shell 3 against the counter roll 2, then the roll shell 3 is slightly flattened here. In contrast, the roll shell 3 is deformed oval under the action of the support members 6, i. the roll shell 3 bends more in the region of the support elements 6 than in other areas. This phenomenon is also called "ovalization". An ovalized roll shell 3 is shown exaggeratedly in FIG.

The roll shell 3 is deformed by the effect of the support elements 6 the stronger, the thinner it is. in the In the present case, the ratio between the inner diameter of the roll shell 3 and its wall thickness is at least 10. The better the roll shell 3 is deformable, the better the resolution of the pressure in the nip 7 in the axial direction.

However, the deformation of the roll shell 3 has the adverse effect of making it difficult to produce and maintain a uniform film of oil between the support member 6 and the roll shell 3. If the oil film is too thin, then there is a risk that the roll shell 3 and the support member 6 are damaged. In extreme cases, it can even come to feed, so for the fixed welding of the support member 6 on the inside of the roll shell. 3

To remedy this problem, a support member 6 is used, which is also highly schematic in Fig. 3 and 4 is shown.

The support member 6 has in a conventional manner a piston 8, which is inserted into a bore 9 in the carrier 4 and there can be pressurized by hydraulic fluid, such as oil. The piston 8 is formed here from a steel.

Placed on the piston 8 is a head 10, which is formed for example of bronze. The roll shell 3 facing end face of the head 10 is referred to as a contact surface 11, even if it does not lie directly on the roll shell 3 in reality, but between the contact surface 11 and the roll shell 3, an oil film to be generated.

In the head 10 a plurality of pressure pockets 12, 13, 14, 15 are arranged, which together form a pressure pocket arrangement. The pressure pockets 12, 13 and 14, 15 are offset in the circumferential direction of the roll shell 3 by a predetermined distance D to each other. At this distance D, a pressure-free zone 16 is arranged, i. There is no pressure pocket in this area and this area can not be pressurized. As can be seen from Fig. 4, the region 16 is open in the axial direction.

The pressure pockets 12-15 (only the pressure pockets 12 and 13 are shown in Fig. 3) are connected via throttles 17, 18 with a line 19, can get over the hydraulic oil from the pressure chamber 9 to the pressure pockets 12-15.

The piston 8 has a diameter ⌀. This results in a piston surface. The pressure pockets 12-15 together have an area larger than the piston area.

As can be seen from Fig. 3, the pressure pockets 12 - 15 are in the circumferential direction of the jacket 3 via the piston 8 via. In Fig. 3 it is shown that they are completely outside of the piston 8. This is not necessary. It is sufficient if they are arranged at least 50% of their area outside the cross-sectional area of the piston 8.

The head 10 is more deformable than the piston 8. In operation, by the pressures in the pressure pockets 12th - 15 forces that bend the head 10 relative to the piston 8, as shown schematically in Fig. 5. As a result, the contact surface 11 adapts to the shape of the shell 3 and it can thus ensure in a simple manner that an oil film 20 between the contact surface 11 and the inside of the shell 3 is relatively uniform. It is not immediately required that the oil film 20 has a constant thickness. However, the variations in thickness should remain within predetermined limits in order to prevent contact between contact surface 11 and the jacket 3.

In order to facilitate the deformation of the abutment surface 11, the head 10 has a configuration in which the ratio between its largest extent a in the circumferential direction of the shell 3 and the thickness b at the edge in the circumferential direction of the shell 3 is in the range of 6 to 18. Preferably, this ratio is greater than 7, and more preferably, this ratio is at least 9. Thus, the head 10, at least in the areas that protrude beyond the piston 8, so yielding that the contact surface 11 can be deformed according to the shape of the shell.

The pressure pockets 12-15 are thus not only used to create a pressure pad on which the roll shell 3 is supported. They are also used to generate the deformation forces with which the contact surface 11 is deformed. This results in a kind of self-regulation. If the head 10 is deformed too much, then a gap between the circumferential in the circumferential direction of the shell 3 respectively outer edges of the pressure pockets 12-15 is too large, so that more hydraulic fluid flows off and the pressure in the pressure pockets 12 - 15 drops. By this self-regulation, it is possible in a simple manner to adapt the shape of the contact surface to the shape of the shell 3.

The deformation of the contact surface can also be achieved in other ways, as will be explained schematically with reference to FIGS. 6 to 9. The same and corresponding parts are provided here with the same reference numerals.

Fig. 6 and 7 show an embodiment of a support member 6, in which on the head 10, two pressure bag carrier 21, 22 are placed. The pressure pad carrier 21, 22 are not directly on the head 10, but are here with the interposition of an elastic member 23 mounted here, which fulfills the function of a spring arrangement. The head 10 may also be integrally formed with the piston 8 in this case, ie consist of the same material. But it is also possible to form the head 10 and the piston 8 as separate elements.

The pressure-bag carrier 22 (the same applies in a corresponding manner to the pressure-bag carrier 21) can be tilted relative to the head 10 to a certain extent due to the elastic element 23. With a corresponding inclination, the elastic intermediate element 23 is compressed in one area and can expand in another area. The consequent skewing of the pressure pad carrier 22 causes the contact surface 11, which is formed by the surfaces of the two pressure pad carrier 21, 22, to the shape of the Roll mantle 3 adapts. It basically plays only a minor role that the pressure pad carrier 21, 22 do not deform themselves. The distance between the pressure pockets 13, 15 in the circumferential direction limiting webs 24, 25 is so small that an altered curvature of the roll shell 3 does not cause problems here.

Nevertheless, due to the elastic intermediate element 23, a small deformation of the pressure-bag carrier 21, 22 per se is also possible.

8 and 9 show a third embodiment in which the pressure pad carrier 21 are hinged suspended in the head 10 of the support member 6. Shown is a hinge joint, in which a hinge axis 26 extends parallel to the axis of rotation of the shell 3. The hinge axis 26 engages in a slot 27 in the pressure pad carrier 21 a. Instead of the illustrated hinge joint and a ball joint is possible. However, the use of a hinge axis 26 has the advantage that the pressure pad carrier 21 is not only held articulated on the head 10, but there is also firmly held.

The pressure pad carrier 21 has a contact surface 28 with the head 10 whose size a2 is smaller than the cross-sectional area a3 of the piston 8. At the same time, the piston surface a3 is smaller than the contact surface a1 between the pressure bag carriers 21, 22 and the roll shell 3. The contact surface a1 comprises while the entire area in which a liquid, such as the oil film 20, a pressure between the pressure pad carrier 21 and the roll shell 3 can build. It therefore also includes the webs 24, 25 of the pressure pad carrier 21, 22nd

The pressure pockets 21 of FIGS. 8, 9 may in turn be formed of bronze or brass, while the head 10 and the piston 8 are formed in this case of steel.

Shown is a deflection adjustment, in which the support member 6 has a direction of action, which is opposite to the effective direction of the support shoes 5. This is advantageous, but not mandatory. For example, a plurality of support elements 6 can be arranged so that the sum of their effective directions of the direction of the axis is directed opposite.

Claims (17)

Bend adjustment with a rotating jacket, a coat passing through the non-rotatable support, at least one support shoe between the support and the jacket, the direction of action corresponds to a press direction, and at least one guided in the carrier piston support member between the support and the jacket, the effective direction in the direction of rotation of the jacket of the press direction and which rests with a contact surface from the inside of the jacket, characterized in that the contact surface (11) is similar to the jacket (3) deformable. Deflection adjustment roller according to Claim 1, characterized in that the abutment surface (11) has a pressure pocket arrangement (12, 15) which has at least two pressure pockets (12, 13; 14, 15) which have a predetermined spacing D in the direction of rotation. Deflection-adjustment roller according to Claim 2, characterized in that a zone (16) with pressure reduced relative to the pressure pockets (12-15) is arranged between the pressure pockets (12, 13; 14, 15) in the direction of rotation of the jacket (3). Deflection-adjustment roller according to claim 2 or 3, characterized in that the pressure pockets (12-15) project beyond the piston (8) at least with part of their surface in the direction of rotation. Deflection adjustment roll according to claim 4, characterized in that the part amounts to at least 50% of the area. Deflection adjustment roll according to one of Claims 1 to 5, characterized in that the support element (6) has a head (10) bearing the abutment surface (11), in which the ratio between the maximum extent (a) in the circumferential direction and its radial thickness (b ) lies on the edge in the range of 6 to 18. Deflection adjustment roll according to one of claims 1 to 6, characterized in that the head (10) is formed of a different material than the piston (8). Deflection adjustment roll according to claim 7, characterized in that the material of the head (10) is easier to deform than the material of the piston (8). Deflection adjustment roll according to one of Claims 2 to 8, characterized in that at least one pressure pocket (12-15) is arranged in a pressure pocket carrier (21, 22) which is arranged to be movable relative to the piston (8). Deflection-adjustment roller according to Claim 9, characterized in that the pressure-pocket carrier (21, 22) is supported on the piston (8) via a spring arrangement. Deflection-adjusting roll according to claim 10, characterized in that the spring arrangement has at least one elastic intermediate element (23). Deflection adjustment roller according to claim 11, characterized in that the intermediate element (23) has a planar extension. Deflection-adjustment roller according to one of Claims 9 to 12, characterized in that the pressure-pocket carrier (21, 22) is connected to the piston (8) via a joint arrangement (26). Deflection adjustment roll according to Claim 13, characterized in that the joint arrangement has a hinge axis (26) which runs parallel to the axis of rotation of the jacket (3). Deflection adjustment roll according to claim 13, characterized in that the joint arrangement comprises a ball joint. Deflection adjustment roller according to one of Claims 13 to 15, characterized in that the pressure-pocket carrier (21, 22) has a contact surface a2 with the piston (8) which is smaller than a cross-sectional area a3 of the piston (8), the piston surface a3 being smaller as a pressure-bag carrier contact surface a1. Deflection adjustment roll according to one of Claims 1 to 16, characterized in that the jacket (3) has a wall thickness which is at most 10% of its inner diameter.

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