JP2017100848A - Endless flat belt and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endless flat belt which can suppress an adhesive failure caused by variations in pressure at the time of pressure-bonding a belt, a higher load on a machine caused by high pressure-bonding the belt in order to prevent the variations in pressure, increase in abrasion loss of the belt, reduction in service life caused by breakage and the like.SOLUTION: An endless flat belt 17 comprises: a tension member layer 18 including an inner rubber layer 1 and a cord core wire 11 buried in the inner rubber layer 1 and wound around spirally at prescribed pitch in a belt width direction; a reinforcement cloth 2 adhered to the inner rubber layer 1; and a surface rubber layer 3 laminated on the surface of the reinforcement cloth 2. A tensile elastic modulus in a belt circumference direction and a tensile elastic modulus in a belt width direction of the tension member layer 18 are 100-5000 MPa and 1-2000 MPa respectively, and a tensile elastic modulus in the belt circumference direction and a tensile elastic modulus in the belt width direction of the reinforcement cloth 2 are 0.1-2000 MPa and 200-2000 MPa respectively.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an endless flat belt suitable for use in running in a twisted state, such as a paper tube winding belt, and a method for manufacturing the same.

Conventionally, flat belts used as high-speed transmission belts are processed with adhesives or thermal bonding after processing both ends of a belt-like belt with a polyamide film as a core body into joint shapes such as skybar joints and finger joints. In general, the endless belt is bonded together.
However, since the adhesive is usually poor in flexibility, when the belt is run with a small-diameter pulley or twisted state, the belt becomes partially hard at the joint, and stress tends to concentrate on that part, and the joint can be made in a short period of time. In some cases, cracks may occur in the part, or the belt may break.
For example, in the manufacture of a paper tube, as shown in FIG. 14, a paper tape 41 is spirally wound around a mandrel 42 and manufactured. The paper tape 41 wound around the mandrel 42 is conveyed in the axial direction by a flat belt 43 (Patent Document 1). The flat belt 43 has a function of being twisted strongly and sending out the paper tube of the paper tube to which the adhesive has been applied.

  In this way, the flat belt used in the manufacture of the paper tube runs at a high speed while being tightly twisted and wound around the paper tape and crimped. For this reason, the belt must be wound around the paper tube at a certain angle and run while being pressed against the paper tube, and the winding pressure tends to be uneven. Further, if the belt tension is further increased and high pressure bonding is applied in order to eliminate pressure unevenness, the belt may have a shortened life due to uneven wear, and may break in some cases. Furthermore, increasing the belt tension increases the load on the machine side. For example, because the belt is strongly wound around a mandrel that winds paper tape, the mandrel wears early and a paper tube failure occurs. Need to be replaced. In addition, if the belt is wound strongly, the power consumption is increased and the running cost is increased. Further, even if the belt is simply softened and wound well, it is strongly twisted, so that the belt deformation becomes large and the belts rub against each other, resulting in uneven wear, leading to a short life.

  On the other hand, as a conventional method for producing an endless flat belt without a joint, both ends of a reinforcing cloth are joined together and covered with a cylindrical mold outer surface according to the belt dimensions, and a cord core wire is wound around this, and further a rubber sheet A method of performing vulcanization molding by covering with the like. This endless flat belt has the advantage that the belt itself has no joint and is excellent in bending resistance and torsion-resistant running. However, in this method, since the belt is formed by laminating materials on the outer surface of the cylindrical mold, the belt circumference depends on the mold circumference, and it is necessary to own a cylindrical mold for each circumference. There is.

  In Patent Documents 2 and 3, a tubular flat knitted fabric (circular knitted fabric) is wound between two rolls in a stretched state, and cord cords are wound at a constant pitch in the belt width direction and bonded together. An endless belt is disclosed. Since there is no connecting part of the reinforcing cloth, the above-mentioned problems do not occur, but the belt circumference is determined by the circumference of the cylindrical flat knitted fabric to be used, so various endless flat belts having different lengths are used. It is difficult to manufacture. In particular, it was difficult to produce a belt having a long circumference.

Japanese Utility Model Publication No. 6-27865 JP 2005-314850 A JP 2013-180832 A

The main problems of the present invention are poor adhesion due to pressure unevenness during pressure bonding of the belt, high load on the machine caused by high pressure bonding to eliminate pressure unevenness, increased amount of wear on the belt, shortened life due to breakage, etc. It is an object to provide an endless flat belt capable of suppressing the above.
Another object of the present invention is to provide a method for producing an endless flat belt that can be easily produced even with a belt having a long circumference without using a cylindrical mold.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, the present invention has the following configuration.
(1) A core body layer including an inner rubber layer, a cord core wire embedded in the inner rubber layer and spirally wound at a predetermined pitch in the belt width direction, and affixed to the inner rubber layer A tensile elastic modulus in the belt circumferential direction of the core layer is 100 to 5000 MPa, a tensile elastic modulus in the belt width direction is 1 to 2000 MPa, and the tensile elasticity in the belt circumferential direction of the reinforcing fabric. An endless flat belt having a modulus of 0.1 to 2000 MPa and a tensile elastic modulus in the belt width direction of 200 to 2000 MPa.
(2) A surface rubber layer is affixed to a surface of the inner rubber layer where the reinforcing cloth is not affixed, or a surface opposite to the surface of the reinforcing cloth affixed to the inner rubber layer. The endless flat belt described.
(3) The reinforcing fabric has a surface rubber layer affixed to a surface opposite to the surface affixed to the internal rubber layer, and the cord core wire is embedded so as to have symmetry about the cord core wire. The endless flat belt according to (1), wherein a reinforcing cloth and a surface rubber layer are laminated in this order on both surfaces of the inner rubber layer.
(4) The endless flat belt according to any one of (1) to (4), wherein the yarn material in the belt circumferential direction of the reinforcing cloth is a stretched processed yarn or elastic yarn. (5) The surface rubber layer. The endless flat belt according to any one of (1) to (4), wherein the surface has a fine uneven shape and the thickness of the surface rubber layer is 0.1 to 5 mm.
(6) A step of applying a rubber sheet to the surface of the reinforcing cloth or applying and drying liquid rubber on the surface of the reinforcing cloth to form an internal rubber layer on the surface of the reinforcing cloth, and bonding both ends of the reinforcing cloth. A cord core wire spirally wound at a predetermined pitch in the width direction of the reinforcing cloth, and embedded in the inner rubber layer to form a core body layer. A step of obtaining a laminate of the reinforcing fabric and the core layer, and a step of performing vulcanization molding by heating and pressurizing the laminate, and the tensile modulus in the belt circumferential direction of the core layer is 100 to 100 The tensile elastic modulus in the belt width direction is 5000 MPa, the tensile elastic modulus in the belt circumferential direction of the reinforcing fabric is 0.1 to 2000 MPa, and the tensile elastic modulus in the belt width direction is 200 to 2000 MPa. A method for producing an endless flat belt.
(7) The reinforcing cloth formed in an endless shape is wound between at least two rotating rolls, and the rotating roll is rotated to wind the cord core wire in a spiral shape at a predetermined pitch in the width direction of the reinforcing cloth. The manufacturing method of the endless flat belt as described in (6).
(8) The method for producing an endless flat belt according to (6) or (7), wherein a rubber sheet for forming a surface rubber layer is superposed on the belt surface and vulcanized under pressure.
(9) The endless flat belt according to any one of (1) to (5), which is a paper tube winding belt.

According to the endless flat belt of the present invention, the tensile elastic modulus in the belt circumferential direction of the core layer is 100 to 5000 MPa, the tensile elastic modulus in the belt width direction is 1 to 2000 MPa, and the tension of the reinforcing cloth in the belt circumferential direction is Since the elastic modulus is 0.1 to 2000 MPa and the tensile elastic modulus in the belt width direction is 200 to 2000 MPa, the belt width direction rigidity against twisting is used in applications where the belt is wound while being twisted, such as a paper tube winding belt. Is maintained, the wrapping pressure can be equalized, the belt can be fed stably even at low tension, and the belt can have a longer service life and power saving.
In addition, according to the method of manufacturing an endless flat belt of the present invention, since both ends of the reinforcing cloth are bonded in advance to make an endless shape, the circumference of the belt can be obtained without using a cylindrical mold as in the prior art. The length of the belt can be freely designed, and even a belt having a long circumference can be easily manufactured.

1 is a schematic cross-sectional view showing an endless flat belt according to an embodiment of the present invention. It is a schematic cross-sectional view showing an endless flat belt according to another embodiment of the present invention. It is a schematic cross-sectional view showing an endless flat belt according to still another embodiment of the present invention. It is process drawing for demonstrating one Embodiment of the manufacturing method of this invention. (a)-(c) is explanatory drawing which shows an example of the joining process of the reinforcement cloth in this invention. It is a perspective view which shows the joint shape of the reinforcement cloth in this invention. (a)-(e) is a perspective view which shows the other joint shape of the reinforcement cloth in this invention. It is explanatory drawing which shows the joint shape by the sewing of the reinforcement cloth using a thread | yarn. It is explanatory drawing which shows the winding process of the cord core wire in this invention. It is a schematic perspective view which shows the method of the belt winding crimping | compression-bonding test in an Example. It is a schematic perspective view which shows the winding angle to the pseudo paper tube of a belt in a belt winding crimping | compression test. (A) is a schematic perspective view which shows the measurement point of the pressure distribution in a belt winding crimping | compression-bonding test, (b) is a figure which shows an example of a measurement result. It is a figure which shows the test result of an Example and a comparative example. It is the schematic which shows the manufacture example of a paper tube.

Hereinafter, an endless flat belt according to an embodiment of the present invention will be described with reference to FIG. The endless flat belt 15 shown in FIG. 1 has a core in which a cord core wire 11 spirally wound at a predetermined pitch in the width direction (indicated by an arrow w) of the endless flat belt 15 is embedded in the inner rubber layer 1. Body layer 18, reinforcing fabric 2 affixed to one side of core body layer 18, one side of core body layer 18 to which reinforcing fabric 2 is not affixed, and surface affixed to core body layer 18 of reinforcing fabric 2 And a surface rubber layer 3 affixed to the opposite surface.
The endless flat belt 16 shown in FIG. 2 has the same structure as the endless flat belt 15 except that the surface rubber layer 3 is attached only to one side of the core body layer 18.
The endless flat belt 17 shown in FIG. 3 has reinforcing cloths 2 and 2 ′ attached to both surfaces of a core body layer 18 in which the cord core wire 11 is embedded in the inner rubber layer 1, and the core body layer 18 of the reinforcing cloth 2 and Each has a structure in which the surface rubber layer 3 is affixed to the opposite surface, and the others have the same structure as the endless flat belt 15. In this example, the reinforcing cloths 2, 2 ′ and the surface rubber layer 3 are laminated on both surfaces of the core body layer 18 in which the cord core wire 11 is embedded in the inner rubber layer 1 so as to have symmetry about the cord core wire 11. Has been.

(Heart body layer 18)
The core body layer 18 has a cord core wire 11 embedded in the inner rubber layer 1 formed by attaching a rubber sheet to one side of the reinforcing cloth 2 or applying and drying liquid rubber on the surface of the reinforcing cloth 2. Is.
(Inner rubber layer 1)
Examples of the material of the inner rubber layer 1 include a group consisting of nitrile rubber, carboxylated nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, chlorosulfonated polyethylene, polybutadiene rubber, natural rubber, EPM, EPDM, urethane rubber, and acrylic rubber. The at least 1 sort selected from more is mentioned. The thickness of the internal rubber layer 1 is preferably 0.1 to 2.0 mm.

(Cord cord 11)
A cord core wire 11 is embedded in the inner rubber layer 1 in the length direction of the belt. The cord core wire 11 is spirally wound at a predetermined pitch in the width direction of the belt. It is preferable that the cord core wire 11 alternately arranges the cord core wire 11a in which the fiber is twisted in the S twist and the cord core wire 11b in which the fiber is twisted in the Z twist in order to suppress the skew during the belt running.
As the cord core wire 11, for example, fibers such as polyamide (PA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), and vinylon are used alone or in combination. Polyamide fibers can also be formed by blending with polyamide fibers such as polyamide 6, polyamide 66, polyamide 46, polyamide 11, polyamide 12, polyamide 610, and copolymers thereof, or other polymers. PET, PBT, PTT, and vinylon can also be blended with other materials. Further, PA, PET, PBT, PTT or vinylon fibers may contain other fibers as long as the performance is not impaired.
The thickness of the cord core wire 11 is usually 470 to 25200 dtex, preferably 880 to 18800 dtex as a twisted yarn in which long fibers or short fibers are aligned and twisted.
The core body layer 18 composed of an inner rubber layer and a cord core wire embedded in the inner rubber layer and spirally wound at a predetermined pitch in the belt width direction has a tensile elastic modulus in the belt circumferential direction. 100 to 5000 MPa, preferably 500 to 3000 MPa, and the tensile modulus in the belt width direction is 1 to 2000 MPa, preferably 10 to 500 MPa. When the tensile elastic modulus of the core body layer 18 is within the above range, the circumferential elongation of the belt is suppressed, and the durability against twisting is excellent. On the other hand, when the tensile elastic modulus of the core body layer 18 is lower than the above range, the belt tension becomes low, and for example, it is impossible to satisfy the transmission capability of feeding out the paper tube. On the other hand, if the above range is exceeded, the tension difference in the belt width direction due to torsion becomes large, so that the winding pressure becomes uneven and the crimping cannot be performed well, and it is necessary to perform high pressure bonding. It is not preferable because a difference in elongation is likely to occur and this leads to a poor press bonding.

(Reinforcing cloth 2)
The reinforcing cloth 2 imparts durability to the belt. The reinforcing cloth 2 has a tensile elastic modulus in the belt circumferential direction of 0.1 to 2000 MPa, preferably 1 to 200 MPa. Further, the tensile elastic modulus in the belt width direction of the reinforcing cloth 2 is 200 to 2000 MPa, preferably 300 to 1000 MPa. As described above, the reinforcing cloth 2 has elasticity in the belt circumferential direction, and the rigidity is maintained in the belt width direction with respect to the twist, so that the winding pressure can be equalized.
In order to provide the stretchability represented by the above-described tensile elastic modulus in the belt circumferential direction of the reinforcing cloth 2, for example, a processed yarn is used in the belt circumferential direction. The processed yarn generally refers to a yarn that gives a fine crimp to the filament yarn and fixes the crimp by heat treatment to give stretchability and bulkiness. As the material, fiber yarns such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyamide can be used. In addition, as a yarn material having elasticity, urethane elastic yarn, polyether ester high elastic yarn, polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), etc. can be used as covered yarn.
The material of the reinforcing fabric 2 that imparts the above-described tensile elastic modulus in the belt width direction is at least one selected from the group consisting of polyamide fiber, aramid fiber, polyester fiber, glass fiber, cotton yarn, vinylon fiber, and polyketone fiber, for example. Formed from two materials. The filament yarn of these fibers is used without being crimped or slightly crimped.

(Surface rubber layer 3)
The surface rubber layer 3 is preferably one suitable for frictional transmission having a stable transmission capability between the belt and the conveyed product or power transmission device on the surface of the endless flat belt 15. Examples of the material of the surface rubber layer 3 include nitrile rubber, carboxylated nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, chlorosulfonated polyethylene, polybutadiene rubber, natural rubber, EPM, EPDM, urethane rubber, acrylic rubber, Examples include silicon rubber. The thickness of the surface rubber layer 3 is 0.1 to 5 mm, preferably 0.2 to 3 mm.

The surface rubber layer 3 may have a fine uneven pattern (so-called basis weight pattern) formed on the surface in order to prevent a decrease in the coefficient of friction with the conveyed product.
The pattern provided on the surface of the surface rubber layer 3 can be formed at the time of vulcanization molding, but may be before vulcanization or after vulcanization. As a forming method, for example, a forming roll or a cloth pattern material having a fine uneven pattern is placed on the surface of the unvulcanized surface rubber layer 3, and then pressure vulcanized. The cloth pattern material is strongly pressed against the surface of the surface rubber layer 3, and vulcanization is proceeded as it is. After the vulcanization is completed, the cloth pattern material is peeled off to provide unevenness on the surface of the surface rubber layer 3.

  Next, the manufacturing method of the endless flat belt of this invention is demonstrated with reference to drawings.

As shown in FIG. 4, the manufacturing method of the endless flat belt 15 according to the embodiment of the present invention includes the following steps (I) to (V) and is performed in the order of steps (I) to (V).
(I) Reinforcement cloth processing step in which a rubber sheet is applied to the reinforcing cloth 2 or liquid rubber is applied and dried (II) A punching process step of the reinforcing cloth 2 that forms convex portions and concave portions respectively corresponding to both ends. Steps for bonding both ends to make the reinforcing cloth 2 endless (IV) Step for winding the cord core wire 11 around the surface of the endless reinforcing cloth 2 to obtain a laminated body (V) Heating and pressing the laminated body Process for sulfur molding

<Process (I)>
As shown in FIG. 5 (a), a rubber sheet is attached to the surface of the belt-shaped reinforcing cloth 2, or liquid rubber is applied and dried, and then cut into a predetermined length. Adhesion of the rubber sheet may use an adhesive or may be performed by heating and pressing. The thickness of the rubber sheet to be used or the coating amount of the liquid rubber is adjusted according to the thickness of the inner rubber layer 1 to be formed.

<Process (II)>
As shown in FIG. 5 (b), in order to form the convex portions 4a and the concave portions 4b of the so-called finger joint shape 4 in which the concavo-convex portions of the respective end faces of the reinforcing fabric 2 are fitted and bonded, Punching is performed. In the finger joint shape 4, a plurality of substantially isosceles triangular convex portions 4a projecting in the longitudinal direction of the belt are formed in one end of the reinforcing cloth 2 in a saw blade shape continuously in the width direction, and the other end is formed on the convex portion 4a. It has a shape provided with a correspondingly shaped recess 4b.
The method for forming the finger joint shape 4 on the reinforcing cloth 2 includes punching, but may be formed by cutting. After punching, it is sent to the next bonding process.

<Step (III)>
As shown in FIG.5 (c), the joint part of the reinforcement cloth 2 fitted by the finger joint shape 4 is heat-pressed with the press machine 5, and both ends are adhere | attached and it is made endless.
FIG. 6 shows the joint shape joined in this way. The width W of the convex part 4a and the concave part 4b shown in FIG. 6 is usually 5 to 100 mm, preferably 10 to 30 mm, and the length L is usually 1000 to 20000 mm, preferably 50 to 150 mm.
Further, in the finger joint shape shown in FIG. 6, the joint is formed orthogonal to the length direction of the reinforcing cloth 2, but as shown in FIG. It may be a finger joint shape (indicated by an arrow F1) formed in an inclined manner. Further, the shape of the finger joint is such that the convex part 4a or the concave part 4b is a shape other than an isosceles triangle, for example, a quadrangle, a substantially semicircular shape, a trapezoidal shape, as indicated by arrows F2 to F5 in FIGS. An uneven shape such as a convex shape may be used.

  In addition, you may sew both ends 12a and 12b of the reinforcement cloth 2 with the thread | yarn 10a and 10b instead of adhesion | attachment like process (II) and process (III), as shown in FIG. FIG. A sewing state by a sewing machine is shown. One is an upper thread 10a and the other is a lower thread 10b. By entwining these threads 10a and 10b, both ends 12a and 12b of the reinforcing cloth 2 can be firmly joined. it can. In addition, in the lower thread 10b, the part which cannot be seen because it is located on the back side of the reinforcing cloth 2 is indicated by a broken line. The two ends 12a and 12b of the reinforcing cloth 2 may be sewn in a state where they are abutted with each other, or may be sewn in a state where there is a gap, as shown by a one-dot chain line in FIG.

<Step (IV)>
As shown in FIG. 9, the endless reinforcing cloth 2 is wound around a cord winding device 7 composed of at least two axes of a drive pulley 7a and a passive pulley 7b to give an appropriate tension. The cord core wire 11 in which the tension is controlled is wound spirally at a predetermined pitch in the width direction of the reinforcing cloth 2 (winding process). As a result, the cord core wire 11 is wound around the reinforcing cloth 2 to obtain a laminate 20 composed of the reinforcing cloth 2 and the core body layer 18 (inner rubber layer 1 and cord core wire 11). The laminated body 20 may be provided with the reinforcing cloth 2 on both surfaces of the core body layer 18.

  The cord core wire 11 is wound so that the cord core wire 11a twisted in S twist and the cord core wire 11b twisted in Z twist are alternately arranged in the width direction of the reinforcing cloth 2. It is preferable for preventing the line. When the peripheral length of the endless reinforcing cloth 2 is long, one or two or more guide rollers (not shown) are provided between the drive pulley 7a and the passive pulley 7b of the cord winding device 7 to lengthen the stroke. do it.

<Process (V)>
A sheet-like rubber material for forming the surface rubber layer 3 is superposed on both surfaces of the laminate 20 and heated and pressurized to simultaneously vulcanize and mold the inner rubber layer 1 and the surface rubber layer 3. The overlapping of the rubber material and the vulcanization molding may be performed continuously. Thus, the endless flat belt 15 shown in FIG. 1 is obtained.
Further, when a sheet-like rubber material for forming the surface rubber layer 3 is superposed on only one side of the laminate 20 and heated and pressurized, an endless flat belt 16 shown in FIG. 2 is obtained.
Furthermore, in the step (IV) shown in FIG. 9, the cord core wire 11 is spirally wound at a predetermined pitch in the width direction of the reinforcing cloth 2, and then the surface on which the reinforcing cloth 2 of the inner rubber layer 1 is pasted. When another reinforcing cloth 2 ′ is stuck to the opposite surface and the surface rubber layer 3 is formed on the outer surface of the reinforcing cloth 2, 2 ′, an endless flat belt 17 shown in FIG. 3 is obtained.

  EXAMPLES Hereinafter, although an Example is given and the endless flat belt of this invention and its manufacturing method are demonstrated, this invention is not limited only to a following example.

Example 1
As a material for the reinforcing fabric, polyamide 66 long fibers are used, and a canvas woven with a yarn density of 71 d / 25 mm of 220 dtex in the belt circumferential direction and a yarn density of 108 d / 25 mm of 235 dtex in the belt width direction is used as the reinforcing fabric. did. Next, after sticking an NBR (nitrile butadiene rubber) sheet, both ends of the canvas were butted together and pressed at 100 ° C. to form an endless canvas.
Next, an endless canvas was wrapped around the drive pulley 7a and the passive pulley 7b of the cord winding device 7 as shown in FIG. Using twisted yarn, while controlling the tension with the tension control device of the cord cord, spirally buried in the NBR sheet of endless canvas, and then wound the polyamide canvas (reinforcing fabric) around the outer surface, Obtained.
Next, an NBR sheet having a thickness of 1 mm is pasted on both surfaces of the laminate and vulcanized to form an endless flat belt having a thickness of 4.6 mm, a width of 115 mm, and a circumferential length of 3300 mm having the structure shown in FIG. Got.

(Example 2)
An endless flat belt having a thickness of 4.2 mm, a width of 115 mm, and a circumferential length of 3300 mm was obtained in the same manner as in Example 1 except that a 1600 dtex polyamide 66 long fiber was used as the cord core wire to obtain a 5600 dtex yarn. Obtained.

(Example 3)
An endless flat belt having a thickness of 4.2 mm, a width of 115 mm, and a circumferential length of 3300 mm was obtained in the same manner as in Example 1 except that a yarn of 5640 dtex was obtained by aligning polyamide 46 long fibers of 470 dtex as the cord core. Obtained.

(Comparative Example 1)
A polyamide canvas and an NBR sheet are laminated in order on both sides of a polyamide film with a thickness of 2.0 mm, vulcanized, and bonded at both ends with an adhesive. The belt thickness is 4.0 mm, the width is 115 mm, and the circumference is 3300 mm. An endless flat belt was obtained.

<Winding crimp test>
As shown in FIG. 10, a pseudo paper tube 21, which is a resin tube having a diameter of 76.2 mm, is installed between a pair of pulleys 22 and 22 (diameter 200 mm), and an endless flat belt 23 is twisted to pseudo paper tube 21 was wound around both pulleys 22 and 22. At this time, as shown in FIG. 11, the insertion angle θ of the belt 23 to the pseudo paper tube 21 was set to 60 degrees. Further, in order to measure the distribution state of the pressure applied to the pseudo paper tube 21 during the belt running, a film type pressure distribution measuring system I-SCAN (Tactile Sensor System; manufactured by Nitta Corporation) is provided on the outer peripheral surface of the pseudo paper tube 21. ) Is wrapped around. In this state, the flat belt 23 was pulled in a stationary state at room temperature, and the pressure distribution applied to the pseudo paper tube 21 was measured.
As shown in FIG. 12A, the pressure distribution was measured from the entrance (I) of the belt 23 to the pseudo paper tube 21 through the intermediate part (II) to the feed part (III). An example of the measured pressure distribution state is shown in FIG. In FIG. 12B, the dark colored portion C in the belt 23 is a high pressure bonding portion, and shows that the pressure decreases as the color becomes lighter.

<Tensile modulus>
The tensile elastic modulus was measured according to JISL1096. In general, the tensile modulus can be obtained from the following equation according to Hooke's law by drawing an auxiliary line to the proportional limit of the stress-strain curve.
Formula: E = σ / ε
(E: tensile elastic modulus (MPa), σ: proportional limit tensile strength (MPa), ε: proportional limit strain)
The proportional limit tensile strength σ and proportional limit strain ε for each material were determined from the range of strain amount 0 to 0.05 of the stress-strain curve obtained from the tensile test.

<Mounting belt tension>
When performing the winding and crimping test, as shown in FIG. 10, the endless flat belt 23 is twisted, wound around the pseudo paper tube 21, wound between the pulleys 22 and 22, and stretched. 23 was attached with a sonic belt tension meter (product name U-508: manufactured by Gates Unitta Asia Co., Ltd.) at a position indicated by a symbol M shown in FIG.

  These test results are shown in FIG. As shown in FIG. 13, in Comparative Example 1, there are many high pressure bonding portions displayed in a dark color on the belt on the entrance side, and the wrapping pressure is not equalized as a whole. On the other hand, in Examples 1-3, there are few high crimping | compression-bonding parts, and it turns out that the winding pressure is equalized as a whole.

  Therefore, it can be seen that the endless flat belt of the present invention is suitable for an application such as a paper tube winding machine in which the belt is twisted to run and wound.

DESCRIPTION OF SYMBOLS 1 Internal rubber layer 2 Reinforcement cloth 3 Surface rubber layer 4 Finger joint shape 4a Convex part 4b Concave part 10a, 10b Sewing thread 11 Cord core wire 15 Endless flat belt 16 Endless flat belt 17 Endless flat belt 18 Core body layer 20 Laminate 21 Pseudo paper tube 22 Pulley 23 Endless flat belt

Claims (9)

A core body layer including an inner rubber layer and a cord core wire embedded in the inner rubber layer and spirally wound at a predetermined pitch in the belt width direction;
A reinforcing cloth affixed to the inner rubber layer,
The core body layer has a tensile modulus in the belt circumferential direction of 100 to 5000 MPa, a tensile elastic modulus in the belt width direction of 1 to 2000 MPa, and
An endless flat belt, wherein the reinforcing fabric has a tensile elastic modulus in the belt circumferential direction of 0.1 to 2000 MPa and a tensile elastic modulus in the belt width direction of 200 to 2000 MPa.   The endless rubber according to claim 1, wherein a surface rubber layer is affixed to a surface of the inner rubber layer to which the reinforcing cloth is not affixed or a surface opposite to the surface of the reinforcing cloth affixed to the inner rubber layer. Flat belt.   The reinforcing rubber has an inner rubber layer in which the cord core wire is embedded so that the surface rubber layer is pasted on the surface opposite to the surface pasted on the inner rubber layer and has symmetry about the cord core wire. The endless flat belt according to claim 1, wherein a reinforcing cloth and a surface rubber layer are laminated in this order on both sides.   The endless flat belt according to any one of claims 1 to 3, wherein a thread material of the reinforcing cloth in a belt circumferential direction is a work thread or an elastic thread having elasticity.   The endless flat belt according to any one of claims 1 to 4, wherein the surface rubber layer has a fine uneven shape, and the surface rubber layer has a thickness of 0.1 to 5 mm. A step of applying a rubber sheet to the surface of the reinforcing cloth or applying and drying liquid rubber on the surface of the reinforcing cloth to form an internal rubber layer on the surface of the reinforcing cloth;
Joining both ends of the reinforcing fabric to make them endless;
A cord core wire is spirally wound at a predetermined pitch in the width direction of the reinforcing cloth on the surface of the endless reinforcing cloth, and embedded in the inner rubber layer to obtain a core body layer. Obtaining a laminate with
Including heating and pressurizing the laminate to perform vulcanization molding,
The core body layer has a tensile modulus in the belt circumferential direction of 100 to 5000 MPa, a tensile modulus of elasticity in the belt width direction of 1 to 2000 MPa, and a tensile elastic modulus of the reinforcing fabric in the belt circumferential direction of 0.1 to 2000 MPa. A method for producing an endless flat belt, wherein the tensile modulus in the width direction is 200 to 2000 MPa.   The reinforcing cloth formed in an endless shape is wound between at least two rotating rolls, and the rotating roll is rotated to wind the cord core wire in a spiral shape at a predetermined pitch in the width direction of the reinforcing cloth. A process for producing an endless flat belt as described in 1 above.   The method for producing an endless flat belt according to claim 6 or 7, wherein a rubber sheet for forming a surface rubber layer is superposed on the surface of the belt and vulcanized under pressure.   The endless flat belt according to any one of claims 1 to 5, which is a paper tube winding belt.