JP2006274448A - Press belt and shoe press roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press belt capable of effectively inhibiting the generation of cracks at both end parts-corresponding regions positioning as corresponding to the both end parts in the width direction of a compressing member such as a press roll, shoe press, etc. <P>SOLUTION: This press belt 2 contains the both end parts-corresponding regions B positioning as corresponding to the both end parts in the width direction of the press roll 1 or the press shoe 3, and a central region A positioning between the both end parts-corresponding regions B. The central region A has a prescribed thickness, and constitutes a compressed part compressed by a compressing means. The end part-corresponding region B constitutes a pressure-passing part for passing the pressure from the compressing means by becoming a recessed part 14 having a smaller thickness than the thickness of the central region A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a press belt and a shoe press roll used for pressurizing an object to be pressed in various industries such as paper industry, magnetic recording medium manufacturing industry, textile industry and the like.

  In various industries, a belt-like press object is placed on a press belt, and the press object is between one pressure member located inside the circumference of the press belt and the other pressure member located outside the circumference of the press belt. The belt press which pressurizes is used. The pressure member here is a press roll, a pressure shoe, or the like. An example of a belt press is a shoe press as a dewatering press in the paper industry.

  The shoe press is briefly explained by taking the paper industry as an example. A press roll as an external pressurizing means located outside the circumference of the press belt and a press shoe as an internal pressurizing means located inside the circumference of the press belt. The surface pressure is applied to the object to be pressed (wet paper) placed on the outer peripheral surface of the press belt via the press belt to perform a pressurizing process (dehydration process). A roll press that performs press with two rolls applies a linear pressure to the object to be pressed, whereas a shoe press applies a surface pressure to the object to be pressed by using a pressure shoe having a predetermined width in the running direction. be able to. For this reason, when the dehydration press is performed by a shoe press, there is an advantage that the nip width can be increased and the dewatering efficiency can be increased.

  In order to make the shoe press compact, for example, as disclosed in Japanese Patent Application Laid-Open No. 61-179359 (Patent Document 1), a pressure shoe as an internal pressure means is replaced with a flexible cylindrical press belt. Shoe press rolls that are covered with a (press jacket) and assembled in a roll form are in widespread use.

  In addition to the dehydration process as described above, for example, in the paper manufacturing industry, magnetic recording medium manufacturing industry, textile industry, etc., the pressing object, such as a calendar process performed to smooth the surface of the pressing object and impart gloss In order to improve the quality of the shoe, a shoe press may be performed instead of the roll press or in combination with the roll press. Typical required properties for press belts include strength, wear resistance, flexibility and impermeability to water, oil, gas and the like. A polyurethane obtained by reacting a urethane prepolymer and a curing agent is generally used for a press belt as a material having these characteristics. However, since severe bending and pressurization are repeated in press belts, particularly shoe press belts, it is a big problem in terms of durability that cracks are easily generated on the outer peripheral surface.

  As a method for solving the above-mentioned problem, Japanese Patent Application Laid-Open No. 10-298893 (Patent Document 2) discloses that the hardness of the resin constituting the belt is high in the central region in the width direction and includes both edge regions. A shoe press belt is disclosed which has improved wear resistance and crack resistance by changing to a lower value. In this case, it is considered that there is an effect that the wear resistance and the pressure deformation resistance are maintained in the central area, and cracks are hardly generated in both edge areas.

  Cracks are likely to occur in a concentrated manner at both end corresponding areas corresponding to both ends in the width direction of a pressing means such as a press roll and a pressure shoe. Strict crack resistance is not required in the central area, which is located between the areas corresponding to both ends and serves as the pressure treatment surface of the pressed object. Rather, wear resistance and pressure deformation resistance should be emphasized. Conceivable.

  Patent Document 2 is based on such a concept, but in order to achieve both wear resistance and crack resistance by changing the hardness, the change in hardness between the central region and both edges is increased to some extent. There is a need to. When the hardness of polyurethane is different, the shrinkage force during molding is different. For this reason, a belt having a large change in hardness in the central region and both edge regions in the width direction has a low cylindricity, which may impair running performance.

As other prior art documents, both ends corresponding to both ends in the width direction of the pressurizing means by making improvements to the shape and structure of the press belt or by changing the depth of the drainage grooves (squeezing grooves) Some have suppressed the occurrence of cracks in the corresponding area. For example, in Japanese Patent Laid-Open No. 2002-180393 (Patent Document 3), the thickness of the intermediate layer of the press belt at positions corresponding to both ends in the width direction of the pressurizing means is increased. In JP-A-2002-327389 (Patent Document 4), the bottom of the drainage groove located at the position corresponding to both ends in the width direction of the pressurizing means is brought close to the reinforcing layer which is an intermediate layer. In US Pat. No. 5,943,951 (Patent Document 5), flexibility is enhanced by gradually changing the thickness of both end portions in the width direction of the press belt. In US Pat. No. 6,030,503 (Patent Document 6), a plurality of recesses different from grooves are provided at both ends of the press belt in the width direction. In Japanese Patent Application Laid-Open No. 11-12975 (Patent Document 7), the depth of drainage grooves at both ends in the width direction of the press belt is reduced.
JP-A 61-179359 JP-A-10-298893 JP 2002-180393 A JP 2002-327389 A US Pat. No. 5,943,951 US Pat. No. 6,030,503 Japanese Patent Laid-Open No. 11-12975

  In the above prior art documents, the occurrence of cracks in this region is typically increased by increasing the flexibility of the region corresponding to both ends of the press belt at the position corresponding to both ends in the width direction of the pressurizing means. Trying to suppress. However, even if the flexibility of the region corresponding to both ends of the press belt is increased, the effect of suppressing crack generation is insufficient.

  When pressurizing is performed on a pressing object such as wet paper by the pressurizing unit, the pressurizing unit applies pressure to the corresponding areas on both ends of the press belt corresponding to both ends in the width direction of the pressurizing unit. The boundary between the part restrained and the part not restrained by the pressing means is located, and a bending force acts on the press belt part located on the outer side in the width direction from the boundary part. That is, the pressing force from the pressurizing means and the bending force inevitably generated during the pressurizing process act synergistically on the boundary portion. For this reason, even if the structure in which the region in the vicinity of the boundary portion is made flexible, the effect of suppressing the occurrence of cracks is insufficient.

  An object of the present invention is to provide a press belt capable of effectively suppressing the occurrence of cracks in both end corresponding regions located corresponding to both ends in the width direction of a press member such as a press roll and a press shoe. Is to provide.

  Another object of the present invention is to provide a shoe press roll using the press belt as an outer cylinder.

  The press belt of the present invention has an endless shape and rotates. The press belt is placed on the outer peripheral surface side of the press belt, and is positioned inside and / or outside the periphery of the press belt. This is used in a method of pressurizing a press object by a pressing means having a width. The press belt includes both end corresponding regions located corresponding to both ends in the width direction of the pressurizing means, and a central region located between the both end corresponding regions. The central region has a predetermined thickness and constitutes a pressed portion to be pressed by the pressurizing means, and both end corresponding regions are added as concave portions having a thickness smaller than the thickness of the central region. The pressure relief part for releasing the pressure from the pressure means is configured.

  Since the region corresponding to both ends of the press belt is a recess having a thickness smaller than the thickness of the central region, the pressure from the pressurizing means is released in the region corresponding to both ends during the pressurizing process on the press object. ing. Therefore, only the bending stress acts on the both end corresponding regions during the pressure treatment, and the high pressure from the pressure means does not act. Thus, according to the present invention having the above-described configuration, it is possible to effectively suppress the occurrence of cracks in the end belt corresponding regions of the press belt.

  Note that the terms “travel direction” and “width direction” used in the present specification refer to the travel direction and the width direction of the press object, respectively, unless otherwise specified. Further, the object to be pressed is a band-shaped material such as a wet paper, a magnetic tape, and a fabric, and is not particularly limited. Further, the pressurizing means is a press roll or a pressure shoe.

  Preferably, the depth of the concave portion in the region corresponding to both ends of the press belt is larger than the amount of change in the thickness dimension of the central region when the pressurizing unit is pressed. With such a depth of the concave portion, a high pressure from the pressurizing means can be surely released in the area corresponding to both ends of the press belt during the pressurizing process on the press object. The depth of the recess is, for example, 1.0 mm or more.

  In one embodiment, the recess is formed on the outer peripheral surface of the press belt. In another embodiment, the recess is formed on the inner peripheral surface of the press belt. As still another embodiment, recesses may be formed on both the outer peripheral surface and the inner peripheral surface of the press belt.

  In one embodiment, an outermost end region having substantially the same thickness as the both end corresponding regions is included outside the both end corresponding regions in the width direction. In another embodiment, the outermost end region having the same thickness as that of the central region is included on the outer side in the width direction of the both-end corresponding region. If the outermost end region of the press belt has substantially the same thickness as the central region, both end portions in the width direction of the felt can be stably supported, so that free movement of the felt can be restricted.

  The press belt includes, for example, a reinforcing layer that extends in both the central region and both end corresponding regions, and an upper elastic layer thereon. In this case, the upper elastic layer has a recess serving as a pressure relief portion.

  In another embodiment, the press belt includes a reinforcing layer that extends in both the central region and both end corresponding regions, and an upper elastic layer that is positioned above and extends only in the central region. In this case, the exposed portion of the outer peripheral surface of the reinforcing layer forms a recess that becomes a pressure relief portion.

You may form many drainage grooves extended along the running direction of a belt in the outer peripheral surface of an upper elastic layer. In this case, preferably, the depth of the concave portion is equal to or larger than the bottom end depth of the drainage groove. The bottom end of the drainage groove in the area corresponding to both ends of the press belt is highly likely to become a starting point of cracking. In this embodiment, in addition to letting the pressure corresponding to both ends correspond to the recesses, the drainage grooves are not formed in this region, so the crack generation suppressing effect is higher.
The press belt according to another embodiment includes a reinforcing layer extending in both the central region and the both end corresponding regions, and a lower elastic layer below the reinforcing layer. In this case, the lower elastic layer has a recess serving as a pressure relief portion.

  The press belt according to still another embodiment includes a reinforcing layer that extends in both the central region and both end corresponding regions, and a lower elastic layer that is positioned below and extends only in the central region. In this case, the exposed portion of the inner peripheral surface of the reinforcing layer forms a recess that becomes a pressure relief portion.

  A shoe press roll according to the present invention includes an outer cylinder made of an endless press belt having the above-described features, and a pressure shoe as a pressure means located inside the periphery of the outer cylinder. Preferably, both ends of the center region of the press belt having a predetermined thickness are located on the inner side in the width direction than both end edge portions of the pressure shoe.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

  FIG. 1 is a diagram showing a cross section in a running direction of a shoe press device used in a press process of a paper machine. The shoe press apparatus includes a press roll as the pressurizing unit 1, a press belt 2 facing the press roll 1, and a press shoe as the pressurizing unit 3 located inside the periphery of the press belt 2. In the apparatus of FIG. 1, the pressure shoe 3 is covered with a press belt 2, and the press belt 2 is assembled in a roll shape with an outer cylinder to constitute a shoe press roll 30, but the press belt 2 is in a roll shape. It can be used as it is without being assembled.

  The size of this type of press belt 2 is generally 2 to 15 m in width, 1 to 30 m in circumferential length, and 2 to 10 mm in thickness.

  The press roll 1 is located outside the periphery of the press belt 2 and functions as one pressing means. The pressure shoe 3 is located inside the circumference of the press belt 2 and functions as the other pressure means. Between the press belt 2 and the press roll 1, a wet paper 5 as a press object is passed over the felt 4. The outer peripheral surface of the press belt 2 and the felt 4 are in direct contact.

  Lubricating oil is supplied between the press belt 2 and the pressure shoe 3, and the press belt 2 can slide on the pressure shoe 3. The press roll 1 is driven to rotate, and the press belt 2 is driven to rotate while sliding on the pressure shoe 3 by frictional force with the traveling felt 4.

  The pressure shoe 3 is pressed toward the press roll 1 from the inside of the press belt 2, and the wet paper 5 is pressed and dehydrated by this pressing force. The surface of the pressure shoe 3 has a concave shape corresponding to the surface of the press roll 1. For this reason, between the press roll 1 and the press belt 2, the pressurization dehydration part P with the wide width | variety in a running direction is formed.

  FIG. 2 is a cross-sectional view of a main part showing a cross-section in the width direction of the pressure dehydrating part P in FIG. As shown in FIG. 2, the press roll 1 and the pressure shoe 3 have a certain length in the width direction. The press belt 2 includes a central area A, both end corresponding areas B, and an endmost area C. The both end corresponding region B is a region corresponding to a part including both end portions 7 of the pressing surface 6 of the press roll 1 and both ends 9 of the pressing surface 8 of the pressing shoe 3. The outermost region C is located outside the both-end corresponding region B.

  In the press belt 2 shown in FIG. 2, the central region A has a predetermined thickness and constitutes a pressed portion to be pressed by the press roll 1 and the pressing shoe 3, and both end corresponding regions B Becomes a recess having a thickness smaller than the thickness of the central region A, and constitutes a pressure relief portion for releasing the pressure from the press roll 1 and the pressure shoe 3, and the endmost region C has substantially the same thickness as the central region A. ing.

  FIG. 3 shows another type of press belt. For the same or corresponding elements, the same numbers as those used in FIG. 2 are used. In the press belt 2 shown in FIG. 3, the central area A has a predetermined thickness, and constitutes a pressed part to be pressed by the press roll 1 and the pressing shoe 3, and corresponds to both end corresponding areas B. Becomes a concave portion having a thickness smaller than the thickness of the central region A to constitute a pressure relief portion for releasing the pressure from the press roll 1 and the pressure shoe 3, and the outermost end region C is substantially the same thickness as the opposite end corresponding region B. It has become.

  FIG. 4A shows an enlarged view of a state in which the wet paper 5 and the press belt 2 that are press objects are sandwiched between the press roll 1 and the pressure shoe 3. In FIG. 4A, the felt 4 is not shown. The press belt 2 is illustrated with a uniform thickness in order to simplify the drawing. 4B to 4F show various shapes of the press belt 2 according to the embodiment of the present invention.

  As shown in FIG. 4A, the end of the wet paper 5 that is the object to be pressed is more than the end 7 of the pressing surface 6 of the press roll 1 and the end 9 of the pressing surface 8 of the pressing shoe 3. It is located inside in the width direction. The end portion corresponding region B of the press belt 2 is a region corresponding to the end portion 7 of the press roll 1 and the end portion 9 of the pressure shoe 3. Specifically, the end corresponding region B extends with a certain extent on both sides in the width direction with the position corresponding to the end 7 of the press roll 1 and the end 9 of the pressure shoe 3 as the center. The wet paper 5 is located on the central area A sandwiched between the opposite end areas B of the press belt 2. The boundary portion between the end portion corresponding region B and the central region A is located approximately in the middle between the end portion of the wet paper 5 and the end portion of the pressurizing means (press roll 1 and pressurizing shoe 3). Although the outermost end region C is located outside the end corresponding region B, the boundary between these two regions is located on the outer side in the width direction than the end of the pressurizing means.

  In a state in which the wet paper 5 is subjected to pressure treatment, a portion of the press belt 2 sandwiched between the pressure surface 6 of the press roll 1 and the pressure surface 8 of the pressure shoe 3 is covered by these pressure means. Be bound. On the other hand, the press belt portion located on the outer side in the width direction from the end portion 7 of the pressing surface 6 of the press roll 1 and the end portion 9 of the pressing surface 8 of the pressing shoe 3 is not restrained by these pressing means. The boundary portion 2 b between the constrained portion and the non-constrained portion of the press belt 2 is located at the end portion 7 of the press roll 1 and the end portion 9 of the pressure shoe 3. At the time of pressurization, as indicated by an imaginary line in FIG. 4A, a bending force inevitably acts on a portion not restrained by the pressurizing means. If high pressure from the pressurizing means is concentrated on the boundary portion 2b of the press belt 2 in addition to the bending force, cracks are likely to occur at the boundary portion.

  In order to effectively suppress the occurrence of cracks in the boundary portion 2b of the press belt 2 as described above, the both-end corresponding region B of the press belt 2 according to the embodiment of the present invention is smaller than the thickness of the central region A. A pressure relief part is formed which becomes a concave part having a thickness and releases pressure from the pressurizing means.

  In the press belt 2 shown in FIG. 4 (b), the central region A and the endmost region C have substantially the same thickness, and the concave portion is recessed with a step on the outer peripheral surface of the end corresponding region B between them. 14 is formed. The depth d of the recess 14 is preferably 1.0 mm or more. Usually, since the amount of change in the thickness dimension of the press belt central region A during the pressurizing process is smaller than 1.0 mm, a high pressure from the pressurizing means can be surely applied to both ends with such a depth of the recess 14. It is possible to escape in the part corresponding area B. The concave portion 14 extends in the traveling direction of the press belt 2.

  In the press belt 2 shown in FIG. 4C, the end corresponding region B is a recess 14 having a thickness smaller than that of the central region A to form a pressure relief portion, and the endmost region C is the end corresponding region. It has almost the same thickness as B. Also in this embodiment, it is preferable that the difference between the depth of the concave portion 14, that is, the thickness of the central region A and the thickness of the end portion corresponding region B is 1.0 mm or more. The concave portion 14 extends in the traveling direction of the press belt 2.

  In the press belt 2 shown in FIGS. 4B and 4C, the end corresponding region B is in the form of a recess having a flat bottom surface. On the other hand, in the press belt 2 shown in FIG. 4 (d), the end corresponding region B has a concave portion 14 having an arc-shaped cross section on the outer peripheral surface thereof. It constitutes the pressure relief part that releases the pressure. The concave portion 14 having an arcuate cross section extends in the press belt traveling direction. The outermost region C has substantially the same thickness as the central region A. Also in this embodiment, preferably, the maximum depth d of the recess 14 is set to 1.0 mm or more.

  In the press belt 2 shown in FIG. 4 (e), a concave portion 14 is formed on the inner peripheral surface of the end portion corresponding region B to constitute a pressure relief portion. The recess 14 formed on the inner peripheral surface extends in the running direction of the press belt. In this embodiment, a step does not appear at the boundary portion between the outer peripheral surface of the central region A and the outer peripheral surface of the end corresponding region B. The outermost region C has substantially the same thickness as the central region A. Preferably, the depth d of the recess 14 on the inner peripheral surface of the press belt 2 is 1.0 mm or more.

  In the press belt 2 shown in FIG. 4 (f), a recess 14 is formed on the inner peripheral surface of the end corresponding region B to form a pressure relief portion, and the endmost region C is substantially the same as the end corresponding region B. It has a thickness. Even in this embodiment, no step appears on the outer peripheral surface of the press belt 2. Preferably, the depth d of the recess 14 on the inner peripheral surface of the press belt 2 is 1.0 mm or more.

  5A and 5B are diagrams showing an example of the press belt 2, wherein FIG. 5A is a sectional view thereof and FIG. 5B is a plan view thereof. The press belt 2 is integrated with the reinforcing layer 10 impregnated with an elastic material in an endless reinforcing base material, and the elastic material located on the outer peripheral surface side of the reinforcing layer 10 and impregnated in the reinforcing base material of the reinforcing layer 10. The upper elastic layer 11 is formed on the inner peripheral surface of the reinforcing layer 10 and the lower elastic layer 12 is integrated with the elastic material impregnated in the reinforcing base material of the reinforcing layer 10.

  As the reinforcing substrate constituting the reinforcing layer 10, a woven fabric made of organic fibers such as polyamide and polyester is used. The entire belt 2 is integrally formed of an elastic material such as thermosetting polyurethane, and has a structure in which a reinforcing base material is embedded in the belt 2.

  As shown in FIG. 5, a large number of drain grooves 13 extending along the belt running direction appear on the outer peripheral surface of the upper elastic layer 11. The drainage groove 13 extends in a spiral shape over the entire width direction of the press belt 2.

  FIG. 6 is an enlarged cross-sectional view of the press belt 2. In the press belt 2, the thicknesses of the both end corresponding regions B corresponding to the both end portions in the width direction of the pressurizing means are made smaller than the central region A and the endmost region C. Specifically, in the upper elastic layer 11, the both end corresponding regions B are indented portions 14 extending annularly along the belt running direction, and therefore the thickness of the both end corresponding regions B is smaller than the other regions. ing.

  In the embodiment shown in FIG. 6, when the depth of the bottom end of the drainage groove 13 is d1 and the depth of the bottom surface of the recessed portion 14 is d2, the depth of the drainage groove 13 so that the relationship d2 ≧ d1 is established. The depth of the recess 14 is selected. With such a dimensional relationship, the drainage grooves 13 are formed in the central region A and the outermost region C, but the drainage grooves are not formed in the both end corresponding regions B.

  Here, specific dimensions are described by way of example. As described above, the press belt 2 generally has a width dimension of 2 to 15 m, a circumferential length of 1 to 30 m, and a thickness of 2 to 10 mm. In such a press belt 2, the width dimension of the both end corresponding region B is about 2 to 15 cm, the thickness of the upper elastic layer 11 is about 1.2 to 8 mm, and the depth d1 of the bottom end of the drain groove 13 is 0.5. The depth d2 of the bottom surface of the recessed portion 14 is about 1.0 to 7 mm. Moreover, the groove width of the drainage groove 13 is about 0.6 to 1.2 mm, and the width of the land portion located between the adjacent drainage grooves 13 is about 0.9 to 3.6 mm.

  According to the embodiment shown in FIG. 6, the following advantages are obtained. First, by reducing the thickness of the both-end corresponding region B, the flexibility of this region can be enhanced, and a pressure relief part for releasing the pressure from the pressurizing means can be configured. Therefore, even if a torsional stress, a bending stress, or the like acts on this region, the generation of cracks can be suppressed because an excessive pressure is not applied from the pressurizing means.

  Secondly, by forming the recessed portion 14 in the upper elastic layer located in the both-end corresponding region B, the drainage groove that is likely to be a starting point of cracks is eliminated, so that the crack generation suppressing effect is high. Preferably, both side wall surfaces 14a of the recessed portion 14 are formed in a tapered shape in which the distance between them decreases as going downward. If the both side wall surfaces 14a of the dent portion 14 are vertical wall surfaces, there is a risk that sharp edges may accumulate at the intersection between the vertical wall surface and the drainage groove 13. In order to prevent the occurrence of such fog, it is preferable that the both side wall surfaces 14a have a tapered shape. Further, in order to avoid stress concentration at the bottom corner portion of the recessed portion 14, the corner portion may be formed in a curved surface shape.

  Third, since the outermost end region C of the press belt 2 has the same thickness as the central region A, both end portions in the width direction of the felt can be stably supported by the outermost region C, and the freedom of the felt is reduced. Can be controlled.

  Fourth, since a large number of drainage grooves are formed on the outer peripheral surface of the outermost region C along the running direction of the belt, the flexibility from the both-end corresponding region B to the outermost region C increases, The effect of suppressing the occurrence of cracks is enhanced.

  7, 8, 9 and 10 show another embodiment of the press belt.

  The press belt 20 shown in FIG. 7 includes a reinforcing layer 21, an upper elastic layer 22, and a lower elastic layer 23. In this embodiment, the drainage groove 24 extends spirally over the entire width direction of the upper elastic layer 22. In the upper elastic layer 22, the portion corresponding to the both end portions B serves as a recessed portion 25 and constitutes a pressure relief portion. The depth of the bottom surface of the recess 25 is smaller than the depth of the bottom of the drainage groove 24. Therefore, the drainage groove 24 also appears on the bottom surface of the recess 25. Also in this embodiment, since both end corresponding region B having a small thickness exhibits good flexibility and constitutes a pressure relief portion, the occurrence of cracks can be suppressed.

  The press belt 40 shown in FIG. 8 includes a reinforcing layer 41, an upper elastic layer 42, and a lower elastic layer 43. In this embodiment, the drainage groove is not formed. In the upper elastic layer 42, the portion corresponding to the both end corresponding region B becomes a recessed portion 44 and constitutes a pressure relief portion, so that the occurrence of cracks in the both end corresponding region B can be effectively suppressed.

  The press belt 60 shown in FIG. 9 includes a reinforcing layer 61, an upper elastic layer 62, and a lower elastic layer 63. In the upper elastic layer 62, a drainage groove 64 extends in a spiral shape over the entire width direction. In this embodiment, almost no upper elastic layer is formed on most of both end corresponding regions B and most end regions C, and is substantially flush with the surface of the reinforcing layer 61. Here, “substantially the same surface” is a concept that includes a skin layer having a thickness of 0.5 mm or less even if the upper elastic layer remains. Further, both end portions 65 of the upper elastic layer 62 located at the boundary portion between the central region A and the both end corresponding regions B are gently curved slopes. In particular, the upper and lower corner portions of the upper elastic layer 62 are gently curved in order to avoid stress concentration.

  In the embodiment shown in FIG. 9, on the outer peripheral surface of the press belt 60, the central region A extends as a convex portion in the press belt traveling direction, and both end corresponding regions B and the extreme end region C are concave in the press belt traveling direction. It is extended. The both-end corresponding region B which is a recess constitutes a pressure relief part for releasing the pressure from the pressurizing means. In addition, it is preferable that the level | step difference of the center area | region A and the both end corresponding area | region B in the outer peripheral surface of the press belt 60 shall be 1.0 mm or more. If a step having such a dimension can be ensured, an upper elastic layer having a thickness of 0.5 mm or more may be left in the region B corresponding to both ends.

  A press belt 70 shown in FIG. 10 includes a reinforcing layer 71, an upper elastic layer 72, and a lower elastic layer 73. In the upper elastic layer 72, the drainage groove 74 extends in a spiral shape over the entire width direction. In this embodiment, almost no upper elastic layer is formed on the endmost region C, and is substantially flush with the surface of the reinforcing layer 71. Further, the upper elastic layer 72 located on the both end corresponding region B has a tapered portion 75 whose thickness gradually decreases toward the endmost region C. As shown in the drawing, a concave groove 76 that is deeper than the bottom end of the drainage groove 74 is formed in the middle of the tapered portion 75. The tapered portion 75 that gradually decreases in thickness acts to relieve stress. In addition, since the drain groove that is likely to be the starting point of the crack is not formed in the concave groove 76, the generation of the crack in this part can be suppressed. In addition, the width dimension of the ditch | groove 76 is about 1 cm-10 cm. Moreover, the recessed part 76 comprises the pressure relief part which escapes the pressure from a pressurization means.

  Next, an embodiment of the shoe press roll 30 according to the present invention will be described with reference to FIG. FIG. 11 is a view showing a cross-section in the width direction of the shoe press roll. The shoe press roll 30 is assembled in a roll shape by covering the press shoe 3 as press means with the press belt 2 and using the press belt 2 as an outer cylinder.

  The pressure shoe 3 is supported on a support shaft 31 by a hydraulic cylinder 32 and can press the press belt 2 upward. End disks 33 are rotatably supported on both ends of the support shaft 31 via bearings 34. The edge of the press belt 2 is bent radially inward on the outer periphery 36 of the end disk 33. The bent portion of the end edge of the press belt 2 is sandwiched between the outer peripheral portion of the end disk 33 and the ring-shaped fixing plate 35 and is fastened and fixed with bolts or the like. Lubricating oil is supplied between the press belt 2 and the pressure shoe 3. In this way, the press belt 2 fixed to the end disk 33 can rotate while sliding on the pressure shoe 3.

  As the press belt 2, those described in the above embodiments can be used. As is apparent from the figure, both ends of the central region A of the press belt 2 are located on the inner side in the width direction than both end edges of the pressure shoe 3.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The press belt according to the present invention can be used for a long period of time because cracks are unlikely to occur in both end corresponding regions where cracks have been easily generated. Therefore, it can be advantageously applied to press belts and shoe press rolls used for pressurizing press objects in various industries such as paper industry, magnetic recording medium manufacturing industry, and textile industry.

It is a figure which shows the cross section of the running direction of the shoe press apparatus used at the press process of a paper machine. It is principal part sectional drawing which shows the width direction cross section of the pressurization dehydration part P in FIG. It is principal part sectional drawing which shows the width direction cross section of the pressurization dehydration part P in FIG. 1, and the thing of a different form is used as a press belt. It is an illustration sectional view showing the structure near one end in the width direction of a pressurization means, (a) shows the structure of an apparatus, and (b)-(f) shows the press belt of various forms. ing. It is a figure which shows the press belt which concerns on one Embodiment of this invention, (a) is the sectional drawing, (b) is a top view. It is an expanded sectional view of one embodiment of the present invention. It is an expanded sectional view of other embodiments of the present invention. It is an expanded sectional view of other embodiment of this invention. It is an expanded sectional view of other embodiment of this invention. It is an expanded sectional view of other embodiment of this invention. It is a figure which shows the cross section of the width direction of the shoe press roll which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Press roll, 2 Press belt, 2b Boundary part, 3 Pressure shoe, 4 Felt, 5 Wet paper, 6 Pressure surface, 7 Both ends, 8 Pressure surfaces, 9 Both ends, 10 Reinforcement layer, 11 Upper elastic layer, 12 Lower elastic layer, 13 drainage groove, 14 recess, 14a side wall surface, 20 press belt, 21 reinforcing layer, 22 upper elastic layer, 23 lower elastic layer, 24 drainage groove, 25 recess, 30 shoe press roll, 31 support shaft , 32 Hydraulic cylinder, 33 End disk, 34 Bearing, 35 Fixed plate, 36 Outer circumference, 40 Press belt, 41 Reinforcement layer, 42 Upper elastic layer, 43 Lower elastic layer, 44 Recessed portion, 60 Press belt, 61 Reinforcement layer, 62 upper elastic layer, 63 lower elastic layer, 64 end water groove, 65 both ends, 70 press belt, 71 reinforcing layer, 72 upper elastic layer, 73 lower elastic layer, 74 drainage groove 75 tapered portion, 76 grooves, A central region, B both end corresponding region, C outermost region.

Claims (15)

A press belt in a press apparatus comprising an endless-shaped press belt that rotates and pressurizing means positioned inside and / or outside the circumference of the press belt,
Both end corresponding regions located corresponding to both ends in the width direction of the pressurizing means, and a central region located between the both end corresponding regions,
The central region has a predetermined thickness and constitutes a pressurized portion to be pressed by the pressing means,
The end belt corresponding region is a press belt that becomes a concave portion having a thickness smaller than the thickness of the central region and constitutes a pressure relief portion for releasing pressure from the pressurizing means. 2. The press belt according to claim 1, wherein a depth of the concave portion is larger than a change amount of a thickness dimension of the central region when the pressure is applied to the pressurizing unit. The press belt according to claim 1 or 2, wherein a depth of the concave portion is 1.0 mm or more. The said recessed part is a press belt in any one of Claims 1-3 currently formed in the outer peripheral surface of the said press belt. The said recessed part is a press belt in any one of Claims 1-3 currently formed in the internal peripheral surface of the said press belt. The press belt according to any one of claims 1 to 5, further comprising an outermost end region having substantially the same thickness as that of the both end portion corresponding regions on the outer side in the width direction of the both end corresponding regions. The press belt according to any one of claims 1 to 5, further comprising an outermost end region having substantially the same thickness as that of the central region on the outer side in the width direction of the both end corresponding region. A reinforcing layer extending to both the central region and the both end corresponding region, and an upper elastic layer thereon,
The press belt according to claim 1, wherein the upper elastic layer has the concave portion. A reinforcing layer extending to both the central region and the both end corresponding regions, and an upper elastic layer located on the reinforcing layer and extending only to the central region, wherein an exposed portion of the outer peripheral surface of the reinforcing layer is the concave portion The press belt according to claim 1, wherein the press belt is formed. The press belt according to claim 8 or 9, wherein a plurality of drain grooves extending along a running direction of the belt are formed on an outer peripheral surface of the upper elastic layer. The press belt according to claim 10, wherein a depth of the concave portion is equal to or larger than a bottom end depth of the drainage groove. A reinforcing layer extending to both the central region and the both end corresponding region, and a lower elastic layer below the reinforcing layer,
The press belt according to any one of claims 1 to 7, wherein the lower elastic layer has the concave portion. A reinforcing layer extending to both the central region and the both end corresponding regions, and a lower elastic layer positioned below and extending only to the central region, the exposed portion of the inner peripheral surface of the reinforcing layer is the The press belt according to any one of claims 1 to 7, wherein a concave portion is formed. An outer cylinder made of an endless press belt, and a pressure shoe as a pressing means located inside the circumference of the outer cylinder,
The said outer cylinder is a shoe press roll which is a press belt in any one of Claims 1-13. The shoe press roll according to claim 14, wherein both ends of a central region of the press belt having a predetermined thickness are positioned on the inner side in the width direction than both end edge portions of the pressure shoe.

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