Method and equipment for supporting a roll mantle in the lateral direction

Abstract: The invention concerns a method for supporting the roll mantle of a roll for a paper machine or equivalent in the lateral direction, in particular in the direction transverse to the principal loading direction, such as the nip plane (NP). In the method, the roll mantle (12) is supported on a stationary roll axle (11) revolvingly and as displaceable in relation to the axle (11) substantially in the principal loading direction. According to the invention, the roll mantle (12) is supported on the roll axle (11) radially by means of glide bearing elements (15, 15a) acting in opposite directions in the lateral direction so that, when the roll mantle (12) is displaced in the principal loading direction (NP), the movement of the roll mantle (12) is guided to take place along a desired curve. The invention also concerns an equipment for supporting the roll mantle.

Description: The invention concerns a method for supporting the roll mantle of a roll for a paper machine in the lateral direction, in particular in the direction transverse to the principal loading direction, such as the nip plane, in which method the roll mantle is supported on a stationary roll axle revolvingly and as displaceable in relation to the axle substantially in the principal loading direction. Further, the invention concerns an equipment for supporting the roll mantle of a roll for a paper machine in the lateral direction, in particular in the direction transverse to the principal loading direction, such as the nip plane, while the roll mantle is supported revolvingly and as displaceable in the principal loading direction on the stationary roll axle radially by means of glide bearing elements acting in opposite directions in the lateral direction and supported on the inner face of the roll mantle. Ordinarily, tubular rolls of paper machines are mounted from the ends of the roll mantle by means of rolling-contact bearings on the roll axle. Such a traditional mode of journalling has its advantages, for example the fact that the journalling can be accomplished quite simply, and so far its cost has been considered to be relatively reasonable. Such a traditional mode of journalling, in which the roll mantle is journalled by its ends as fixed on the axle, is, however, not suitable for even nearly all applications in paper machines. In quite a number of cases, the roll mantle must be able to move in the radial direction in relation to the roll axle, which property is required quite frequently, for example, from variable-crown rolls which are in nip contact with a back-up roll. In addition to the fact that, by means of the crown variation means in a variable-crown roll, attempts are made to shape the roll mantle in the desired way in particular for regulation of the profile of linear load, the roll ends must also be able to move in the radial direction in relation to the roll axle in order that the profile of linear load could also be controlled in the end areas of the roll. Besides the properties of profile regulation in the end areas of the roll, regulation of the loading in the end areas of the roll also affects the control of the temperatures in the end areas. This is why rolls have also been developed in which the entire roll mantle can move in the direction of the load radially in relation to the roll axle. One such roll is described in the applicant's EP Patent No. 0,332,594 of earlier date, in which the end bearings of a variable-crown roll are not mounted directly on the central axle of the roll, but the bearings are fitted on separate annular parts, which can move radially in relation to the roll axle. The variable-crown roll in accordance with this publication is a nip roll, and the radial movement of the roll mantle is restricted to the direction of the nip plane. The movement has been accomplished so that, between said annular parts and the roll axle, hydraulic power units are fitted, which shift the end bearings by means of a hydraulic pressure medium towards the nip or away from the nip. The principal objective of this solution is opening and closing the nip. There are also a great number of other rolls of similar type, which produce a substantially similar operation, accomplished with a somewhat different technique. The use of rolling-contact bearings in a roll also produces considerable drawbacks and/or problems for the manufacture and operation of a roll. It is one drawback that the rolling-contact bearings require respective machining of the roll mantle. The wear of the bearings may also produce problems and, further, the rolling-contact bearings impose their limitations in respect of the fluid used in the roll. For example, the following properties can be considered to be drawbacks of the traditional mode of journalling. Limitations of speed: Even at present, the speeds of rotation of the rolls exceed the highest permitted speeds specified by bearing manufacturers. Accuracy of rotation: Further improvement of the accuracy of rotation of an assembled roll with the prior-art technology is very difficult. In a traditional roll, even if all the components (bearings, bearing housings, outer face of the mantle) are machined as precisely as possible, the errors are summed up in an assembled roll. Arrangement of the journalling of the roll mantle by means of glide bearings is also known from the prior art. Such rolls with glide bearings are described, for example, in the US Patents Nos. 5,060,357 and 5,111,563 . In the roll in accordance with the US Patent 5,060,357, the roll mantle is provided with rolling-contact bearings fitted in the areas of its end pieces, which bearings are fitted on separate annular parts of a type similar to those mentioned in the above EP Patent 0,332,594. The roll is meant to be a nip roll, and its roll mantle can move in the direction of the nip plane in relation to the roll axle, for example, for the purpose of opening and closing the nip. The lateral support of the roll mantle, i.e. the support in the direction transverse to the nip plane, is arranged by means of quite a complicated construction of glide bearings, by whose means the movement of the roll mantle can be made to take place exactly in the direction of the nip plane. A drawback of this construction is expressly the complexity of the construction, among other things with a number of glide faces and articulated-joint arrangements, for which reason the reliability in operation, the controllability, and the dependability of the construction cannot be considered to be very good. In the US Patent 5,111,563, an arrangement of support of a roll with glide bearings in the lateral direction is described, which arrangement is simpler than the solution of said US Patent that was mentioned earlier. In this solution, the arrangement of glide bearings in the lateral direction has, however, been accomplished by means of an arrangement of articulated joints by whose means a linear movement of the roll mantle in the direction of the nip plane cannot be produced. In particular in nip rolls, it is important to be able to produce a linear movement, for example, out of the following reasons. If the diameter of the rolls (either of said roll with glide bearings or of the back-up roll) is changed, the nip point is shifted if the roll mantle does not move along a linear path. If the axle of a variable-crown roll is placed at different levels at the opposite ends, without a linear movement the rolls that form the nip are placed crosswise. This again produces axial forces, wear of the bearings, felts, etc, changes the structure of the felt, produces picking of the felt, etc., all of which factors have a substantially deteriorating effect on the runnability and on the quality of the paper. A further considerable problem is the passing of so-called fibre "clods" into the nip. If the roll mantle does not perform a linear movement, there is the risk that the force produced by said "clod" has not an effect that opens the nip, as a result of which the construction may be broken. The object of the present invention is to provide a method and an equipment of a novel type for supporting the roll mantle of a roll meant for a paper machine in the lateral direction, by means of which method and equipment some of the drawbacks involved in the prior art are avoided and by means of which, at the same time, a substantial improvement is achieved over the prior-art constructions and methods. In view of achieving this, a method according to claim 1 and an equipment according to claim 4 have been developed. By means of the invention, a number of remarkable advantages are obtained over the prior art, the most important one of said advantages being that the roll mantle can be made to perform a linear movement in its principal loading direction, in particular in the direction of the nip plane. Owing to this linear movement, in particular when rolls that form a nip are concerned, the nip point remains unchanged even if the diameters of the rolls that form the nip were changed. It is a further advantage that the rolls that form the nip remain parallel to one another and, thus, do not become placed crosswise when the roll mantle moves in the direction of the nip plane even if the roll axle were placed at different levels at opposite ends. The further advantages and characteristic features of the invention come out from the following detailed description of the invention. In the following, the invention will be described by way of example with reference to the figures in the accompanying drawing. Figure 1 is a fully schematic sectional side view of a roll with glide bearings in accordance with the invention, which roll is a variable-crown roll in the exemplifying embodiment shown in Fig. 1. Figure 2 is a schematic sectional view taken along the line II-II in Fig. 1. Figure 2A is a schematic perspective view of an exemplifying embodiment of a preferred construction of the axial support. Figure 3 is a schematic sectional view of an arrangement of support of the roll mantle in a roll provided with glide bearings. Figure 4 is a more detailed illustration of the embodiment of support arrangement as shown in Fig. 3. Figure 5 shows an embodiment alternative to the arrangement shown in Fig. 4. Figure 6 is a sectional view taken along the line VI-VI in Fig. 5. Thus, Figs. 1 and 2 are fully schematic sectional views of a tubular roll with glide bearings in accordance with the invention, so that Fig. 1 is a sectional view of the roll taken in the axial vertical plane, and Fig. 2 is a sectional view of the roll of Fig. 1 taken along the line II-II in Fig. 1. In Figs. 1 and 2, the roll is denoted generally with the reference numeral 10, and in these embodiments the roll 10 is a variable-crown roll which comprises a stationary roll axle 11 on which a roll mantle 12 is fitted revolving, said mantle 12 being supported on the roll axle by means of hydraulic loading elements 17. The hydraulic loading elements 17 are effective in the direction of the nip plane, and by their means it is possible to regulate the shape of the roll mantle 12 and to control the nip profile in the axial direction of the roll. The roll 10 as shown in Figs. 1 and 2 is a roll provided exclusively with glide bearings, so that the roll 10 has no conventional rolling-contact bearings fitted at the roll ends. The journalling of the roll 10 has been accomplished by means of glide bearing elements, of which elements the glide bearing elements that act in the loading direction, i.e., in the case of the roll shown in Figs. 1 and 2, in the direction of the nip plane, are denoted with the reference numerals 14 and 14a. The first glide bearing elements 14 act in the direction of the nip, i.e. against the load, and the second glide bearing elements 14a act in the opposite direction. In the exemplifying embodiment of Figs. 1 and 2, moreover, it is shown that the roll 10 is also provided with glide bearing elements 15,15a acting in the direction transverse to the loading direction, said elements 15,15a acting in opposite directions. Since the roll 10 is a roll fully provided with glide bearings, it is also provided with glide bearing elements 16,16a which act in the axial direction in opposite directions, said elements being supported by the intermediate of a fluid film against the roll ends 13,13a. As is shown in Figs. 1 and 2, the glide bearing elements 14,15,14a,15a acting in the radial direction are supported against the inner face of the roll mantle 12 by the intermediate of a fluid film. In the illustration of Fig. 1, the glide bearing elements 14,14a,15,15a acting in the radial direction have been arranged in pairs so that, of each glide bearing element, there are two elements, which are fitted side by side in the axial direction. In view of the operation, such an arrangement is, however, not an indispensable requirement, for the journalling can also be accomplished, for example, by means of single glide bearing elements. On the other hand, it is shown in Fig. 2 that the glide bearing elements 14,14a,15, 15a are fitted to act in the loading direction and in the direction transverse to said direction. However, there may also be a higher number of glide bearing elements, which are fitted to act radially in different angular positions. Regarding the glide bearing elements effective in the axial direction, it can be stated further that, differing from Fig. 1, the axial movements of the roll mantle 12 can be controlled by means of single glide bearing elements 16,16a acting in the same plane in opposite directions. On the other hand, there may also be a greater number of such axial glide bearing elements 16,16a, which are distributed, for example, as uniformly spaced so as to act upon the inner faces of the roll ends 13,13a. In Fig. 2A, a more advantageous embodiment of the axial glide bearing elements is shown. According to this embodiment, the axial glide bearing elements 16b are annular glide bearings, into whose support face, which rests against the roll end 13,13a, oil pockets 108 have been formed. Similarly, into the roll axle 11, an annular groove 16c has been formed, in which the "piston part" of the glide bearing element 16b has been fitted. The axial support can also be arranged so that glide bearing elements 16b are supported against the same roll end 13 from opposite sides, in which case axial glide bearings are not needed at the other end of the roll. Fig. 3 is a schematic sectional view of a first embodiment of the support of the roll mantle 12 in the direction transverse to the loading direction. Like in Figs. 1 and 2, so also in Fig. 3, the roll mantle is denoted with the reference numeral 12 and the roll axle with the reference numeral 11. To begin with, the general construction of the solution used for lateral support of the roll mantle 12 will be described. As was already stated earlier, the roll mantle 12 is supported on the roll axle 11 by means of bearing elements 15,15a fitted in the direction transverse to the loading direction and acting in opposite directions. As regards their operation, the glide bearing elements 15,15a are conventional, so that said glide bearing elements 15,15a are supported against the inner face 12' of the roll mantle by means of a fluid film. In the illustration in Fig. 3, frame pieces 23,23a have been mounted on the roll axle 11, and the glide bearing elements 15,15a are provided with cavity spaces 21,21a that can be pressurized with a hydraulic pressure medium, said frame pieces 23,23a being fitted to penetrate into said cavity spaces. The frame pieces 23,23a are sealed by means of seals against the cavity spaces 21,21a of the glide bearing elements 15,15a. The outer ends 23',23'a of the frame pieces 23,23a are shaped spherical, in which case said spherical outer ends 23',23'a, which are supported against the cylindrical inner walls of the cavity spaces 21,21a of the glide bearing elements 15,15a by means of the seals, form an articulated bearing, on whose support the glide bearing element 15,15a can pivot. In Fig. 3, the distance of the journalling point of the articulated bearing from the nip plane NP is denoted with the reference d, and the straight line passing through the journalling point, drawn with the dashed-dotted line, is denoted with the reference j. Into the outer faces of the glide bearing elements 15,15a, in the conventional way, oil pockets 24,24a have been formed, which communicate with the cavity spaces 21,21a, which can be pressurized, through capillary bores 25,25a. Thus, pressure medium that is used for loading the glide bearing elements 15,15a passes from the cavity spaces 21,21a through the capillary bores 25,25a into the oil pockets 24,24a to form a fluid film between the glide bearing elements 15,15a and the inner face 12' of the roll mantle. The pressure medium that is used for loading the glide bearing elements 15,15a is passed into the roll along a central duct 20, from which it is passed to the glide bearing elements 15,15a through a feed duct 19. The feed duct 19 does, however, not communicate with the glide bearing elements 15,15a directly, but the roll is provided with a regulation device 26, which distributes the pressure medium to the glide bearing elements 15,15a. The frame piece 23 of the first glide bearing element 15 is hollow, comprising a cavity 23", in which said regulation device 26 is fitted. From this regulation device 26, the pressure medium is passed into the cavity space 21 of the first glide bearing element 15 along the pressure duct 35 and into the cavity space 21a of the second glide bearing element 15a along the connecting duct 18 and along the pressure duct 35a which has been formed into the frame piece 23a of the second glide bearing element 15a. The first embodiment of the method and the device in accordance with the invention is illustrated in more detail in Fig. 4 in the drawing, which shows a detail of Fig. 3. First, with reference to Figs. 3 and 4, it can be stated that, in Fig. 3, the dashed lines show the roll mantle 12 as shifted in the direction of the nip plane NP over the distance s from the basic or central position indicated by solid lines. When the roll mantle 12 moves in the way indicated in Fig. 3, the glide bearing elements 15,15a, while following the inner face 12' of the roll mantle, pivot around their articulation points. This is also illustrated by dashed lines in respect of the first glide bearing element 15 in Figs. 3 and 4. As was already stated earlier, a regulation device 26 is fitted in the cavity 23" in the frame piece 23 of the first glide bearing element 15, which regulation device 26 distributes the pressure medium to both of the glide bearing elements 15,15a acting in the lateral direction. Said regulation device 26 comprises a valve, a three-part slide 29,30,31 being fitted in the bore 36 that has been formed into the frame of said valve. The middle part 29, the first end part 30, and the second end part 31 of the slide communicate with one another through the spindle 27, and said slide parts 29,30,31 are placed at a distance from one another so that, between the slide parts, flow passages 32,33 remain for the pressure medium. The first flow passage 32 communicates through the pressure duct 35 with the cavity space 21 of the first glide bearing element 15, and similarly the second flow passage 33 communicates through the connecting duct 18 and through the pressure duct 35a, which has been formed into the frame piece 23a of the second glide bearing element 15a, with the cavity space 21a of the second glide bearing element 15a. Behind the three-part slide 29,30,31 of the regulation device 26, on the bottom of the bore 36, a spring 28 has been installed, which loads the slide 29,30,31 towards the glide bearing element 15. The end of the spindle 27 that is directed towards the glide bearing element 15 is shaped conical in the way shown in Fig. 4. Onto the glide bearing element 15, a projection 22 has been formed, which is directed inwards in its cavity space 21 and whose end face 22' rests against the tip of the conical end of the spindle 27. The pressure medium is passed to the regulation device 26 from the central duct 20 along the feed duct 19, and into the bore 36, at the feed duct 19, an annular groove 34 has been formed, through which the pressure medium has access in the desired way through the first and/or second flow passage 32,33 into the cavity space 21/21a of the first and/or the second glide bearing element. As was stated above, by means of the regulation device 26, the lateral forces applied to the roll are compensated for. The regulation device 26 is accomplished so that, through it, the pressure of the pressure medium is passed to both glide bearing elements 15,15a so that a higher pressure is passed to the side of the load to shift the roll mantle 12 against the external load. When Fig. 3 is examined, it can be seen that, if an external load is applied against the direction of loading of the first glide bearing element 15, the three-part slide 29,30,31 is pushed, in Fig. 4, against the force of the spring 28 to the left, opens the first flow passage 32 and closes the second flow passage 33. Then, the pressure of the pressure medium coming from the feed duct 19 is passed through the first flow passage 32 and through the pressure duct 35 into the cavity space 21 of the first glide bearing element 15, at the same time as the middle part of the slide prevents access of the pressure into the cavity space 21a of the second glide bearing element 15a. Thus, a higher pressure passes into the cavity space 21 of the first glide bearing element 15, whereby said pressure corrects the position of the mantle to the correct location. The construction of the regulation device 26 is such that even a very little movement of the roll mantle 12 controls the flow and the pressure in the desired way. According to Fig. 4, this has been accomplished in a simple way so that the axial length of the middle part 29 of the slide is substantially equal to, or slightly shorter than, the axial length of the annular groove 34 that has been formed into the bore 36. Since the length of the middle part 29 of the slide is substantially equal to the axial length of the annular groove 34 that has been formed into the bore 36, for example, by means of the shape of the middle part 29 of the slide, it is achieved that, in the middle position shown, oil has access to both of the glide bearing elements 15,15a. Immediately when the slide 29,30,31 is shifted away from the middle position shown in Fig. 4, the flow passage is opened into one of the cavity spaces 21,21a, at the same time as the flow into the opposite cavity space is closed. Thus, the regulation device 26 reacts immediately and without delay to movements of the roll mantle 12. The object of the invention is to provide a solution with which the roll mantle 12 moves in the direction of the nip plane NP along a linear path irrespective of the position of the roll axle 11. This has been achieved by means of a contact in accordance with the invention between the valve spindle 27 of the regulation device 26 and the first glide bearing element 15 (end face 22' of the projection 22), which contact has been arranged so that, when the roll mantle 12 moves, the glide bearing elements 15,15a do not move in the loading direction, i.e. in the direction of the nip plane NP, in relation to the roll axle 11, but they exclusively pivot in relation to their articulation points. It is a problem in carrying out the linear movement how the glide bearing element 15 can sense in what way it must position itself in relation to the roll mantle 12. In the first embodiment of the invention as shown in Fig. 4 this has been accomplished as follows. It is the principal idea in the embodiment of Fig. 4 that the support face that has been formed on the glide bearing element 15 and that is supported against the conical tip of the valve spindle 27 of the regulation device 26, i.e. the end face 22' of the projection 22, has been shaped so that the glide bearing elements 15,15a are positioned in the desired way in relation to the roll mantle 12. In more detail, by means of a geometric examination, the shape of the end face 22' of the projection 22 can be defined such that the movement of the glide bearing element 15 takes place in the desired way. According to Fig. 4, when the movement of the point P fixed to the valve spindle 27 of the regulation device 26 (to the conical tip of the spindle 27) in the system of XY-coordinates fixed to the glide bearing element 15 (to the support face 22' of the projection 22) is examined, in which system of coordinates the Y-axis is directed perpendicularly to the plane bottom of the cavity space 21 of the glide bearing element 15, and the X-axis is perpendicular to said direction, the equations that follow later can be presented so as to determine the shape of the support face 22' of the projection 22, i.e. the shape of the guiding face. In Figs. 3 and 4, a situation is examined in which the roll mantle 12 moves in a linear way over the distance s in the direction of the nip plane NP. When the movement s is 0, the point P fixed to the spindle 27 is in the origin of the system of XY-coordinates. Of the denotations used in Fig. 3, the denotation 1 means the perpendicular distance of the point P from the nip plane NP, the reference d, as was already stated above, denotes the perpendicular distance of the straight line j, i.e. of the journalling point between the first glide bearing element 15 and the frame piece 23, from the nip plane NP, and the reference r denotes the distance of the centre point of the journalling between said first glide bearing shoe 15 and the frame piece 23 from the centre point of the roll mantle 12. In a corresponding way, concerning the denotations used in Fig. 4, it can be stated that the reference h denotes the distance perpendicular to the nip plane NP of the point P from the straight line j passing through the articulation point between the first glide bearing element 15 and the frame piece 23, whereas the reference t denotes the distance of the point P from the centre point of the articulation between the first glide bearing element and the frame piece 23 as directed at the centre point of the roll mantle 12 when the roll mantle 12 has been shifted over the distance s in the direction of the nip plane NP. Then, when using the denotations of Figs. 3 and 4 and based on the geometry, the following formulas (1) and (2) are obtained: s r = x h t h = d r On the other hand, from the condition of location in the system of coordinates, the equation (3) is obtained: y = r - l - t From a geometric examination of Fig. 3, the equation (4) is obtained: r = s 2 + d 2 The X-coordinate of the point P is now obtained as a function of s by placing the equation (4) in the equation (1), whereby the equation (5) is obtained: x = s · h s 2 + d 2 In a corresponding way, the Y-coordinate of the point P can be solved by making use of the equations (2), (3), (4), whereby the equation (6) is obtained, which presents the Y-coordinate of the point P as a function of s: y = s 2 + d 2 - l - d · h s 2 + d 2 Now, from the equations (5) and (6), it is possible to solve the equation of the curve in which Y is given as a function of X. Then the equation is: y = d h h 2 - x 2 - l - h 2 - x 2 Thus, this curve in accordance with the equation (7) represents the shape of the support face 22' of the projection 22, i.e. the shape of the guiding face, with which, in the embodiment of Fig. 4, a linear movement in the direction of the nip plane NP can be provided for the roll mantle 12. Figs. 5 and 6 show an embodiment alternative to the solution as shown in Fig. 4. The illustration in Fig. 5 corresponds to Fig. 4, and Fig. 6 is a schematic partial sectional view taken along the line VI-VI in Fig. 5. Thus, also in the embodiment of Fig. 5, the roll mantle 12 is supported on the roll axle 11 by means of bearing elements 15,15a fitted in the direction transverse to the loading direction, said bearing elements acting in opposite directions. Thus, the bearing elements 15,15a are supported in the conventional way by means of a fluid film against the inner face 12' of the roll mantle. The illustration in Fig. 5 is quite far similar to the illustration in Fig. 4, so that the frame pieces 23,23a are mounted on the roll axle 11, and the glide bearing elements 15,15a are provided with cavity spaces 21,21a that can be pressurized by means of a hydraulic pressure medium, said frame pieces 23,23a being fitted to penetrate into said cavity spaces. The frame pieces 23,23a are sealed by means of seals against the cavity spaces 21,21a of the glide bearing elements 15,15a. Also in this embodiment, the outer ends 23',23'a of the frame pieces 23,23a have been shaped spherical, in which case said spherical outer ends 23',23'a, which are supported by means of a seal against the cylindrical inner walls of the cavity spaces 21,21a of the glide bearing elements 15,15a, form an articulated bearing, on whose support the glide bearing element 15,15a can pivot. Also in Fig. 5, the straight line passing through the journalling point of the articulated bearing is drawn with a dashed-dotted line and denoted with the reference j. The distance of this journalling point from the nip plane NP is denoted with the reference d, as was indicated in Fig. 3. In the way described above, oil pockets 24,24a have been formed onto the outer faces of the glide bearing elements 15,15a, which pockets communicate through capillary bores 25,25a with the pressurized cavity spaces 21,21a. Pressure medium that is used for loading the glide bearing elements 15,15a is transferred from the cavity spaces 21,21a through said capillary bores 25,25a into the oil pockets so as to form a fluid film between the glide bearing elements 15,15a and the inner face 12' of the roll mantle. The pressure medium is passed to the glide bearing elements 15,15a along the central duct 20, from which it is passed to the glide bearing elements 15,15a through the feed duct 19. The distribution of the pressure medium to the glide bearing elements 15,15a acting in opposite direction is arranged by means of a regulation device 26, which is fitted in the cavity 23" in the hollow frame piece 23 of the first glide bearing element 15. Said regulation device 26 distributes the pressure medium to the glide bearing elements 15,15a so that the pressure medium is passed into the cavity space 21 of the first glide bearing element 15 along the pressure duct 35 and into the cavity space 21a of the second glide bearing element 15a through a connecting duct 18 that has been formed into the roll axle 11 and through a pressure duct 35a that has been formed into the frame piece 23a of the second glide bearing element 15a. The regulation device 26 comprises a valve similar to that described in connection with Fig. 4, so that a bore 36 has been formed into the frame of the regulation device 26, into which bore a three-part slide 29,30,31 has been fitted, in which the parts of the slide are connected with one another by means of a spindle 127, so that flow passages 32,33 remain between the slide parts for the pressure medium. The annular groove shown at the feed duct 19 is denoted with the reference numeral 34 also in Fig. 5. The embodiment of Fig. 5 differs from that of Fig. 4 as follows. In the illustration in Fig. 5, the spring 128 which loads the slide of the regulation device 26 is fitted in the bore 36 behind the first end part 30 of the slide to load the slide in the radial direction of the roll inwards. Into the bottom of the cavity space 21 of the glide bearing element 15, a recess 40 has been formed, and into this recess a support piece 41 has been attached, in the embodiment of Fig. 6, by means of fastening screws 42 or equivalent so that a free space remains in the recess 40 underneath the support piece 41. Onto the support piece 41, a support face K has been formed that is directed outwards in the direction of the radius. The spindle 127 of the regulation device 26 has been extended so that said spindle 127 penetrates into the recess 40 that has been formed into the glide bearing element 15. At the outer end of the spindle 127, a plate 27A, disk or equivalent has been fitted, which is transverse to the longitudinal direction of the spindle 127, said plate 27A being supported against the support face K while loaded by the spring 128. The support face K is curved and shaped as an arc of a circle, the centre point of its radius R being placed in the centre point of the roll mantle 12. The distance Z of the curved support face K in the direction of the radius from the inner face 12' of the roll mantle is invariable, the contact point between the plate 27A and the support face K being always at said invariable distance Z from the inner face 12' of the roll mantle. This is why, when the roll mantle 12 moves, for example, through the distance s shown in Fig. 3, said movement of shifting takes place along a linear path in the direction of the nip plane NP, because the curve radius R of the support face K and the distance Z of the support face from the inner face 12' of the roll mantle are invariable in the way described above. Thus, when the roll mantle 12 is shifted in the direction of the nip plane NP, the regulation device 26 does not attempt to correct the location and position of the roll mantle 12 in an incorrect way. It is a preferred further embodiment of the solution shown in Fig. 5 that the distance Z of the support face K from the inner face 12' of the roll mantle is made large enough so that the support face K is placed on the straight line j. In this embodiment, when the roll mantle 12 moves, no gliding movement takes place at the contact point between the support face K and the plate 27A, but said contact point moves rolling along the support face K. Thus, there is no friction at all that might possibly disturb the operation. In Figs. 4 and 5, precise and detailed examples were given of preferred embodiments of the invention. As regards these examples, it should, however, be ascertained that, in the embodiment of Fig. 4, it is essential that, onto the glide bearing element 15, a face that presses the spindle 27 of the regulation device 26 has been machined or formed in some other way, said face being shaped so that, when the roll mantle 12 is shifted, this shifting movement takes place along a linear path. Similarly, it is essential of the embodiment of Fig. 5 that, onto the glide bearing element 15, a face that pulls the spindle 127 of the regulation device 26 has been machined or formed in an equivalent way, the shape of said face being already described above. Also in the other respects, it can be stated that, above, the invention has been described by way of example only with reference to the figures in the accompanying drawing. The invention is, however, not confined to the exemplifying embodiments shown in the figures alone, but different embodiments of the invention may show variation within the scope of the inventive idea defined in the accompanying patent claims.

Claims: A method for supporting the roll mantle (12) of a roll (20) for a paper machine in the lateral direction, in particular in the direction transverse to the principal loading direction, such as the nip plane (NP), in which method the roll mantle (12) is revolvingly supported on a stationary roll axle (11) and is displaceable in relation to the roll axle (11) substantially in the principal loading direction, wherein the roll mantle (12) is radially supported on the roll axle (11) by means of at least two glide bearing elements (15, 15a) acting in opposite directions in the lateral direction so that, when the roll mantle (12) is displaced in the principal loading direction, the movement of the roll mantle (12) is guided to take place along a substantially linear path in the principal loading direction, and wherein said glide bearing elements (15, 15a) are loaded by means of the pressure of a hydraulic pressure medium, characterized in that the flow and the pressure of the pressure medium that loads said two glide bearing elements (15, 15a) acting in opposite directions in the lateral direction are regulated by means of a regulation device (26) which is controlled by means of the movement of the roll mantle (12) by the intermediate of the movement of one (15) of said glide bearing elements (15, 15a) such that the pressures loading said glide bearing elements (15, 15a) maintain said roll mantle (12) at its location on the substantially linear path. A method as claimed in claim 1, characterized in that the regulation device (26) comprises a slide valve having a slide (29, 30, 31), wherein the slide is controlled by means of the movement of the roll mantle (12). A method as claimed in claim 1 or claim 2, characterized in that said glide bearing elements (15, 15a) that act in opposite directions in the lateral direction are guided to comply with the movement of the roll mantle (12) so that, when the roll mantle (12) is shifted in the principal loading direction in relation to the roll axle (11), said glide bearing elements (15, 15a) are kept substantially stationary in the principal loading direction in relation to the roll axle (11). An equipment for supporting the roll mantle (12) of a roll (10) for a paper machine in the lateral direction, in particular in the direction transverse to the principal loading direction, such as the nip plane (NP), wherein the roll mantle (12) is supported revolvingly on a stationary roll axle (11) and is displaceable in the principal loading direction, the equipment comprising at least two glide bearing elements (15, 15a) acting in opposite directions in the lateral direction for radially supporting the roll mantle (12), said glide bearing elements (15, 15a) being supported on the inner face (12') of the roll mantle and said glide bearing elements (15, 15a) being loaded by means of the pressure of a hydraulic pressure medium, wherein said glide bearing elements (15, 15a) are arranged to support the roll mantle (12) so that the movement of the roll mantle (12) in the principal loading direction is guided to take place along a substantially linear path, characterized in that said glide bearing elements (15, 15a) are connected to a regulation device (26) which distributes the pressure and the flow of the hydraulic pressure medium to said two glide bearing elements (15, 15a) acting in opposite directions in the lateral direction so that the pressures loading said glide bearing elements (15, 15a) maintain said roll mantle (12) at its location on the substantially linear path. An equipment as claimed in claim 4, characterized in that the regulation device (26) comprises a slide valve having a slide (29, 30, 31) with a spindle (27, 127) and in that on one (15) of said glide bearing elements a guide face (22', K) is formed which controls said slide (29, 30, 31) and against which said spindle (27, 127) is supported by means of the force of a spring (28, 128). An equipment as claimed in claim 5, characterized in that said guide face (22') is formed on a projection (22) fitted in a pressurized cavity space (21) of said one glide bearing element (15), the tip of said spindle (27) being arranged to be supported against, and to travel along, said guide face (22'). An equipment as claimed in claim 5 or claim 6, characterized in that said guide face (22') is shaped such that, in accordance with the position and location of said one glide bearing element (15), said slide (29, 30, 31) is positioned in the desired way and, as a result of this, the roll mantle (12) can be made to move along the substantially linear path. An equipment as claimed in claim 5, characterized in that said guide face (K) formed on said one glide bearing element (15) has a shape that is convex radially outwards and is substantially determined by an arc of a circle, and that on said spindle (127) a plate (27a) or a plate-shaped piece is mounted which is arranged to be supported against said guide face (K).

Inventors: NISKANEN JUHANI, NISKANEN, JUHANI
Applicants: METSO PAPER INC, METSO PAPER, INC.
Application year: 1995
Main classification: D21G1
IPC codes: F16C13, D21G1