JPWO2015198700A1 - Belt connection structure, conveyor belt and belt connection method - Google Patents

Abstract

The connection strength between cords is easily and reliably improved. The present invention provides a single long cord (2a) extending from one end (10a) and a single or multiple short cords (3a) having a shorter extension distance than the long cord. A belt having one cord group parallel in the width direction in order and the other cord group in which the long cord (2b) and the short cord (3b) extending from the other end (10b) are parallel in the width direction. A connection structure, wherein the short cord (3a) of one cord group is abutted with the short cord (3b) of the other cord group, and the long cord (2a) of the one cord group is the length of the other cord group It has an overlapping region (J) juxtaposed with the cord (2b), and a transition region (T1, T2) formed between the overlapping region and the one end, and this transition region (T1, T2) Then, the long cord (2a) of one cord group is bent so as to shift to one side in the width direction, and is adjacent to one side in the width direction of this long cord (2a). The short cord (3a) is bent so as to shift to the other side in the width direction.

Description

  The present invention relates to a belt connection structure, a conveyor belt, and a belt connection method.

  Belt conveyors that are used for transporting mineral resources and earth and sand from the mining site to the shipping port, etc., use belts in which reinforcing linear cores (cords) are embedded. In recent years, this belt is also frequently used for a pipe conveyor that is used by rounding the conveyance surface into a cylindrical shape in order to prevent spillage during conveyance.

  As shown in FIG. 6, the belt has a cord 102 arranged in multiple rows in the width direction, an intermediate rubber layer 103 filled around the cord 102, and a front surface and a back surface of the intermediate rubber layer 103. It is formed by connecting the laminated body 101 provided with the abrasion-resistant cover rubber layer 104 laminated | stacked endlessly.

  As a method of connecting the end portions of the laminate 101, generally, (A) the cover rubber layer 104 and the intermediate rubber layer 103 are removed at a pair of end portions of the laminate 101, and a fixed-length cord 102 is exposed. And (B) a step of abutting a pair of ends of the laminated body 101 where the cords 102 are exposed, and alternately arranging the cords 102 extending from one end and the cords 102 extending from the other end. And (C) disposing an unvulcanized rubber composition that forms an intermediate rubber layer 103 around the belt 102 in the thickness direction and width direction of the cords 102 that are alternately arranged, and (D) the intermediate rubber layer A step of laminating an unvulcanized rubber composition for forming a cover rubber layer 104 on the front surface and the back surface of 103, and (E) vulcanizing the unvulcanized rubber composition to obtain an intermediate rubber layer 103 and a cover rubber layer 104. Forming process How having been taken is.

  In the juxtaposition of the cords in the step (B), if the cord diameter is larger than the spacing in the width direction between the cords, the cord spacing is reduced, and the width of the rubber filled between the cords is reduced. There is a risk that the connection strength of the portion will be reduced and breakage. Therefore, for example, a step is provided in the length of the cord extending from the end of the belt to prepare a long cord and a short cord, and the distance between the cords is increased by abutting the short cords extending from different ends. A connection method has been devised (see JP 2002-145428 A).

  According to the method of abutting the short cords described above, the width of the filled rubber can be increased by increasing the interval between the juxtaposed cords. In this method, as shown in FIG. 7, the cords 102 in the regions before and after the overlapping region J (the first transition region T1 and the second transition region T2) where the cords 102 extending from the pair of ends are juxtaposed. Is shifted in the width direction of the belt. Here, as shown in FIG. 7, the short cord 102a extending from the pair of ends is abutted without being shifted in the first transition region T1 and the second transition region T2, and only the long code 102b is The transition region T1 and the second transition region T2 are shifted in the width direction.

  However, in the conventional connection method, as shown in FIG. 7, between the adjacent short cord 102a and the long cord 102b extending from the same end portion that does not contribute to the improvement of the connection strength of the connection portion (shaded in FIG. 7). It is difficult to say that there are many invalid areas I) to be shown and the connection strength can be sufficiently improved.

JP 2002-145428 A

  The present invention has been made based on the above circumstances, and a belt connection structure that can easily and surely improve the connection strength between cords extending from a pair of belt end portions, and the belt connection structure. It is an object of the present invention to provide a belt conveyor used and a belt connecting method.

  As a result of intensive studies to solve the above-mentioned problems, the inventors have made uniform the stress applied to the long cord and the short cord in the connection structure in which the long cord and the short cord are extended from the pair of end portions as shown in FIG. It has been found that the connection strength between the cords of the connecting portion can be improved by sharing them with each other. In other words, the present inventors observed that the cord breaks in the transition region when the belt having the connection structure was broken by running while applying high tension and vibrating, and the long cord and the short cord were observed. Then, it was confirmed that the fracture forms were different. The long cord is considered to be a failure caused by two modes of bending and tension, and the short cord is considered to be a failure caused only by the tensile mode. From this, the present inventors estimated that the load received by the long and short cords is large and small, and the connection strength between the cords is weakened due to the imbalance of the load. Based on such estimation, the present inventors have found that the connection strength between the cords of the connecting portion can be improved by uniformly sharing the stress applied to the long cord and the short cord.

  That is, the invention made in order to solve the above problems is a single length that is disposed between a pair of opposed end portions of a flat belt in which a plurality of cords are embedded in the longitudinal direction and extends from one end portion. A long cord and a single cord group in which a single cord or a plurality of short cords having a shorter extension distance than the long cord are arranged in parallel in a predetermined order in the width direction, and a length that similarly extends from the other end. A belt provided with the other cord group in which the cord and the short cord are arranged in the width direction in the opposite order to the one cord group, and a rubber layer filled around the one cord group and the other cord group in combination The short cord of the one cord group is abutted with the short cord of the other cord group in the longitudinal direction between the pair of end portions, and the long cord of the one cord group is the other cord. Along with the group long code And a pair of transition regions that are formed between both end edges of the overlapping region and the pair of end portions and shift the position in the width direction of each cord of one cord group and the other cord group. In this transition region on one end side, the long cord of one cord group is bent so as to shift to one side in the width direction, and the short cord adjacent to one side in the width direction of this long cord is It is bent to shift to the other side of the direction.

  In the belt connection structure, in the transition region on one end side, the long cord of one cord group is bent so as to shift to one side in the width direction, and adjacent to one side in the width direction of the long cord. The short cord is bent so as to shift to the other side in the width direction. As a result, the connection structure of the belt can reliably reduce the distance between adjacent cords extending from one end in the overlapping region, and can reduce the ineffective region that does not contribute to the connection strength. can get. Moreover, since the stress applied to each cord arranged in parallel in the width direction is dispersed by the above configuration, the shear stress applied to the connecting portion of the belt can be reduced by the connection structure of the belt. Also, since the adjacent cords extending from the one end portion are bent so as to shift in the opposite direction of the width direction, the next adjacent cord is bent using the previously bent cord as a mark during the belt connecting operation. Therefore, the work efficiency at the time of connection is improved by the connection structure of the belt.

  The long code and the short code in the one code group and the other code group may be alternately continued. In this way, the long code and the short code in one cord group and the other cord group are alternately continued, so that the area of the region between adjacent cords extending from the same end portion in the overlapping region is smaller. Thus, the connection strength of the belt is further improved.

  The average distance in the width direction in the overlapping region of the long code and the short code shifted so as to approach each other in the overlapping region is preferably 0.1 mm or more and 2 mm or less. Thus, by setting the average interval in the width direction in the overlapping region of the long code and the short code shifted so as to be close to each other in the overlapping region within the above range, the region between adjacent cords extending from the same end portion The area of the belt is reliably reduced in the overlapping region, and the connection strength of the belt is more reliably improved.

  The average inclination angle of the long cord and the short cord in the pair of transition regions is preferably 1.5 ° or more and 2.5 ° or less. In this way, by setting the average inclination angle of the long cord and the short cord in the pair of transition regions within the above range, sufficient connection strength can be obtained while suppressing the lengthening of the overlapping region in the longitudinal direction of the belt. It is done.

  The long cord of one cord group is bent so as to shift to one side in the width direction at the substantially central portion in the longitudinal direction of the overlapping region, and the long cord of the other cord group is shifted to the other side in the width direction. It is preferable to have a central transition region to be bent. In this manner, the long cord of one cord group is bent so as to shift to one side in the width direction at the substantially central portion in the longitudinal direction of the overlapping region, and the long cord of the other cord group is bent in the other side in the width direction. By having the central transition region that is bent so as to shift to the side, the stress applied to each cord arranged in parallel in the width direction can be more uniformly distributed, and the shear stress at the connecting portion of the belt can be further reduced.

  The cord is preferably a steel cord. Thus, by using a steel cord as a cord, the tear strength, impact resistance, and the like can be improved in combination with the improvement in connection strength due to the above-described cord combination structure.

  Moreover, the belt conveyor manufactured using the connection structure of the said belt has high intensity | strength in a connection part, and is excellent in durability.

  Another invention made to solve the above problems includes a step of extending a plurality of cords at a pair of opposite ends of a flat belt in which a plurality of cords are embedded in the longitudinal direction, and the pair of ends. A step of forming a plurality of cords extending to a portion into a long cord and a single cord or a plurality of short cords having a shorter extension distance than the long cord in a predetermined order, and a transition region on the one end side Bending the long cord of one cord group so as to shift to one side in the width direction and bending the short cord adjacent to one side in the width direction of this long cord to shift to the other side in the width direction; Matching the short code of one code group with the short code of the other code group, juxtaposing the long code of one code group with the long code of the other code group, and combining the one code group and the other code group Code group A connecting method of a belt and a step of disposing a rubber layer around.

  The belt is connected by bending the long cord of one cord group so as to shift to one side in the width direction in the transition region on one end side, and shorting adjacent to one side in the width direction of this long cord. The cord is bent so as to shift to the other side in the width direction. Thereby, the connection method of the belt can reliably reduce the distance between adjacent cords extending from one end in the overlapping region, and can reduce the ineffective region that does not contribute to the connection strength. can get. In addition, since the stress applied to the cords arranged in the width direction is dispersed by the connection method, the belt connection method can reduce the shear stress applied to the connection portion of the belt.

  The “width direction average interval” means an average value of the intervals between the two cords in the longitudinal section where the two cords are arranged in parallel. “Inclination angle” means the absolute angle of the central axis of the cord with respect to the longitudinal direction of the belt when the longitudinal direction of the belt is 0 ° in plan view, and “average inclination angle” means a plurality of cords Is the average value of the inclination angles. The “substantially central portion of the overlapping region in the longitudinal direction” means a region including a predetermined range before and after the longitudinal direction with reference to the longitudinal center position of the overlapping region. Of these, it means a region having a distance within 30% of the longitudinal length of the overlapping region from the center position in the longitudinal direction of the overlapping region.

  As described above, the belt connection structure, belt conveyor, and belt connection method of the present invention can easily and reliably improve the connection strength between the cords extending from the pair of belt ends.

It is a typical top view showing arrangement of a cord in a belt connection structure concerning one embodiment of the present invention. It is typical sectional drawing in the AA line of FIG. It is the typical top view to which the 1st transition area | region peripheral part of FIG. 1 was expanded. It is a typical top view which shows arrangement | positioning of the cord in the connection structure of the belt which concerns on embodiment different from embodiment of FIG. (A) It is a graph which shows the stress change of the connection part of the belt of an Example. (B) It is a graph which shows the stress change of the connection part of the belt of a comparative example. It is typical sectional drawing which shows the connection structure of the conventional belt. It is a typical top view which shows arrangement | positioning of the cord in the connection structure of the conventional belt.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

  The belt connection structure 1 shown in FIGS. 1 and 2 is disposed between a pair of opposite ends of a flat belt in which a plurality of cords B are embedded in the longitudinal direction. The belt connection structure 1 includes a cord group (first cord group) extending from one end, a cord group (second cord group) extending from the other end, and belts of these cord groups. The intermediate rubber layer 4 is filled around the thickness direction and the width direction, and the cover rubber layer 5 is laminated on both surfaces of the intermediate rubber layer 4.

  FIG. 1 is a schematic plan view showing the arrangement of the first cord group and the second cord group excluding the intermediate rubber layer 4 and the cover rubber layer 5 in the belt connection structure 1. The belt connection structure 1 includes an overlapping region J where the plurality of cords of the first cord group and the plurality of cords of the second cord group are abutted or juxtaposed. The belt connection structure 1 includes a first transition region T1 formed between one end edge of the overlapping region J and one belt end 10a, and the other end edge of the overlapping region J and And a second transition region T2 formed between the other belt end 10b. Further, the belt connection structure 1 has a central transition region T3 at a substantially central portion in the longitudinal direction of the overlapping region J.

<Code group>
In FIG. 1, the first cord group includes a single long cord 2a extending from one belt end 10a and a single short cord 3a having a shorter extension distance than the long cord 2a. In parallel with the width direction of the belt. In the second cord group, a single length long cord 2b and a single length short cord 3b extending from the other belt end portion 10b are arranged in parallel in the width direction in the opposite order to the first cord group. ing. Here, assuming that the lower side in FIG. 1 is one side in the width direction of the belt and the upper side is the other side in the width direction of the belt, the predetermined order is specifically one from the other side in the width direction of the belt. A plurality of long codes 2a, 2b and short codes 3a, 3b are alternately arranged toward the side. Note that the intermediate rubber layer 4 extending from the same end portion and in the region between adjacent cords does not contribute to the improvement of the connection strength. In FIG. 1, the area that does not contribute to the improvement of the connection strength of the intermediate rubber layer 4 is defined as an ineffective area I and is indicated by shading.

  In the overlapping region J, the short code 3a of the first code group is abutted with the short code 3b of the second code group, and the long code 2a of the first code group is juxtaposed with the long code 2b of the second code group. ing.

  Further, in the first transition region T1, the long code 2a of the first code group is bent so as to shift to one side in the width direction, and the short code 3a adjacent to one side in the width direction of the long code 2a is changed in the width direction. It is bent to shift to the other side. Similarly, in the second transition region T2, the long code 2b of the second code group is bent so as to shift to the other side in the width direction, and the short code 3b adjacent to the other side in the width direction of the long code 2b is set to the width. It is bent to shift to one side of the direction.

  Further, in the central transition region T3 at the substantially central portion in the longitudinal direction of the overlapping region J, the long code 2a of the first code group is bent so as to shift to one side in the width direction, and the long code 2b of the second code group is It is bent to shift to the other side in the width direction. By bending the long cord 2a in the central transition region T3 in this way, the long cord 2a and the second cord of the first cord group in the overlapping region J on the other belt end 10b side than the central transition region T3. The distance between the long codes 2b of the group and the distance between the long code 2a of the first code group and the short code 3b of the second code group can be made equal. Similarly, by bending the long cord 2b of the second cord group in the central transition region T3 as described above, the second cord group in the overlapping region J on the one belt end portion 10a side than the central transition region T3. The distance between the long code 2b and the long code 2a of the first code group and the distance between the long code 2b of the second code group and the short code 3a of the first code group can be made equal. Thereby, the bias | biasing of the stress concerning each code | cord | chord parallel to the width direction is suppressed.

  FIG. 3 is a schematic plan view in which a peripheral portion of the first transition region T1 in FIG. 1 is enlarged. In FIG. 1, the first transition region T1, the second transition region T2, and the central transition region T3 are simplified so that the longitudinal ends thereof are formed along the width direction of the belt. Yes. However, in practice, in order to disperse the stress applied to the connecting portion of the belt in the longitudinal direction, it is preferable to form each transition region so as to be inclined with respect to the width direction of the belt as shown in FIG. In FIG. 3, in order to make the explanation easy to understand, the inclination angle θ1 of the long cord 2a and the inclination angle θ2 of the short cord 3a are illustrated at an angle larger than the actual angle.

  As described above, in the first transition region T1, the long cord 2a of the first code group is bent so as to shift to one side in the width direction, and the adjacent short cord 3a is bent so as to shift to the other side in the width direction. Therefore, the long code 2a and the short code 3a are close to each other in the overlapping region J as shown in FIG.

  The lower limit of the average distance Zn in the width direction in the overlapping region J of the long cord 2a and the short cord 3a that are close to each other in the overlapping region J is preferably 0.1 mm, and more preferably 0.2 mm. On the other hand, the upper limit of the average interval Zn is preferably 1.5 mm, and more preferably 1.2 mm. When the average interval Zn is less than the above lower limit, the arrangement of the cords may be difficult in consideration of the movement of the cords in the width direction when the rubber composition after the cords are disposed is filled. On the other hand, when the average interval Zn exceeds the upper limit, the ineffective area I that does not contribute to the improvement of the connection strength cannot be sufficiently reduced, and the connection strength may not be sufficiently improved.

  The average interval in the width direction in the overlapping region J of the long code 2b and the short code 3b of the second code group that are shifted in the width direction in the second transition region T2 and close in the overlapping region J is the same as the average interval Zn. It is preferable to set it as the range. The average distance in the width direction in the overlapping region J of the long code 2b and the short code 3b in the second code group is the average interval in the width direction in the overlapping region J of the long code 2a and the short code 3a in the first code group. It is preferable to be equal to Zn. When these average intervals are equal, it is difficult for stress applied to each cord in the belt width direction to occur, and the connection strength is easily improved.

  The lower limit of the average distance Zw in the width direction in the overlapping region J between the long code 2a of the first code group and the long code 2b of the second code group adjacent in the overlapping region J is preferably 4 mm, 4.5 mm Is more preferable. On the other hand, the upper limit of the average interval Zw is preferably 15 mm, and more preferably 10 mm. When the said average space | interval Zw is less than the said minimum, the area | region of the intermediate | middle rubber layer 4 which contributes to the improvement of connection strength becomes small, and there exists a possibility that sufficient connection strength may not be obtained. On the other hand, when the average interval Zw exceeds the upper limit, the belt width may be unnecessarily increased.

  In the overlapping region J, the average distance in the width direction in the overlapping region J between the short code 3a of the first code group and the long code 2b of the second code group adjacent in the width direction is also in the same range as the average interval Zw. It is preferable that Further, the average distance in the width direction of the short code 3a of the first code group and the long code 2b of the second code group in the overlapping region J is the same as that of the long code 2a of the first code group and the long code 2b of the second code group. It is preferable to be equal to the average interval Zw in the width direction in the overlapping region J. Further, the average distance in the width direction in the overlapping region J of the long code 2a of the first code group and the short code 3b of the second code group adjacent in the width direction in the overlapping region J is the same as the average interval Zw. It is preferable to set it as the range. Further, the average interval in the width direction of the long code 2a of the first code group and the short code 3b of the second code group in the overlapping region J is also the same as that of the long code 2a of the first code group and the long code 2b of the second code group. It is preferable to be equal to the average interval Zw in the width direction in the overlapping region J. When these average intervals are equal, it is difficult for stress applied to each cord in the belt width direction to occur, and the connection strength is easily improved.

  In the first transition region T1, the lower limit of the average inclination angle θ1 for bending the long cord 2a of the first code group to be shifted to one side in the width direction is preferably 1.5 °, more preferably 1.6 °. preferable. On the other hand, the upper limit of the average inclination angle θ1 is preferably 2.5 °, more preferably 2.4 °. When the average inclination angle θ1 is less than the lower limit, the length in the longitudinal direction of the first transition region T1 increases in order to bring the long code 2a and the short code 3a of the first code group sufficiently close to each other in the overlapping region J. The belt connection structure area may be too long. Conversely, when the average inclination angle θ1 exceeds the upper limit, stress concentration on the cord tends to occur in the longitudinal direction, and sufficient connection strength and shear stress may not be obtained.

  Similarly, in the first transition region T1, the lower limit of the average inclination angle θ2 for bending the short cord 3a adjacent to one side in the width direction of the long code 2a of the first code group so as to shift to the other side in the width direction. Is preferably 1.5 °, more preferably 1.6 °. On the other hand, the upper limit of the average inclination angle θ2 is preferably 2.5 ° and more preferably 2.4 °.

  The upper limit of the difference between the average inclination angle θ1 and the average inclination angle θ2 is preferably 1.0 °, more preferably 0.8 °. When the difference exceeds the upper limit, there is a possibility that stress bias applied to each cord arranged in parallel in the belt width direction cannot be sufficiently suppressed. On the other hand, the lower limit of the difference is 0 °, and it is preferable that the average inclination angle θ1 and the average inclination angle θ2 are equal.

  In addition, a preferable range of the average inclination angle for bending the long code 2b of the second code group so as to shift to the other side in the width direction in the second transition region T2 is a preferable range of the average inclination angle θ1 in the first code group. It is the same. In addition, a preferable range of the average inclination angle for bending the short cord 3b adjacent to the other side in the width direction of the long cord 2b of the second code group so as to shift to the one side in the width direction is the average inclination in the first code group. This is the same as the preferable range of the angle θ2.

  Further, the average inclination angle θ1 for bending the long cord 2a to be shifted to one side in the first transition region T1, the average inclination angle θ2 for bending the short cord 3a to be shifted to the other side, and the long code in the second transition region T2 It is preferable that the average inclination angle for bending 2b to shift to the other side and the average inclination angle for bending short code 3b to shift to one side are substantially equal. By making these average inclination angles substantially equal, the stress applied to each cord at the connecting portion of the belt can be made uniform, and the connection strength is easily improved. Note that making the average inclination angle substantially equal includes a mechanical error range, for example, the difference between the two average inclination angles is 0.5 ° or less, preferably 0.3 ° or less. Say.

  The average diameter d of the cords (the long cords 2a and 2b and the short cords 3a and 3b) included in the belt connection structure 1 is not particularly limited, and may be, for example, 2 mm or more and 15 mm or less.

  The material of the cord used for the belt connection structure 1 is not particularly limited. For example, synthetic fibers such as nylon, polyester, and aramid, steel, and the like can be used. Among these, steel is particularly preferable from the viewpoint of strength, elongation, life and the like.

  The lower limit of the length in the longitudinal direction of the overlapping region J is preferably 500 mm, and more preferably 700 mm. On the other hand, the upper limit of the length in the longitudinal direction of the overlapping region J is preferably 3000 mm, and more preferably 2000 mm. If the length of the overlapping region J in the longitudinal direction is less than the lower limit, sufficient connection strength may not be obtained at the belt connecting portion. On the other hand, if the length of the overlapping region J in the longitudinal direction exceeds the upper limit, the work time for connecting the belt becomes longer and the material cost required for the connection may increase.

  As a minimum of the longitudinal direction length of the 1st transition field T1 and the 2nd transition field T2, 30 mm is preferred and 50 mm is more preferred. On the other hand, the upper limit of the length in the longitudinal direction of the first transition region T1 and the second transition region T2 is preferably 150 mm, and more preferably 120 mm. If the lengths in the longitudinal direction of the first transition region T1 and the second transition region T2 are less than the lower limit, the bias of stress applied to each cord in the width direction cannot be sufficiently suppressed, and the connection strength between the cords in the connection portion is reduced. There is a possibility that it cannot be improved sufficiently. Conversely, if the longitudinal lengths of the transition region T1 and the second transition region T2 exceed the upper limit, the belt connection structure region may be too long.

  Moreover, as a minimum of the longitudinal direction length of the said center transition area | region T3, 10 mm is preferable and 20 mm is more preferable. On the other hand, the upper limit of the length in the longitudinal direction of the central transition region T3 is preferably 50 mm, and more preferably 40 mm. If the length in the longitudinal direction of the central transition region T3 is less than the lower limit, stress concentration on the cord may easily occur in the longitudinal direction. On the other hand, if the length in the longitudinal direction of the central transition region T3 exceeds the upper limit, it may be difficult to perform work when the belt is connected.

<Intermediate rubber layer>
The intermediate rubber layer 4 is formed of a rubber composition filled around the combined first cord group and second cord group. Examples of the base rubber of the rubber composition forming the intermediate rubber layer 4 include natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), ethylene-propylene rubber (EPM, EPDM), isoprene rubber ( IR), acrylonitrile-butadiene rubber (NBR, NIR, etc.) and the like.

  The rubber composition forming the intermediate rubber layer 4 is added with a vulcanizing agent such as sulfur, organic peroxide, metal oxide, phenol resin, quinone dioxime and the like. Examples of sulfur-based vulcanizing agents include powdered sulfur, precipitated sulfur, highly dispersible sulfur, surface-treated sulfur, insoluble sulfur, dimorpholine disulfide, alkylphenol disulfide, and the like. Examples of organic peroxide vulcanizing agents include benzoyl peroxide, t-butyl hydroperoxide, 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy). ) Hexane, 2,5-dimethylhexane-2,5-di (peroxylbenzoate), and the like. Examples of the metal oxide vulcanizing agent include zinc white and magnesium oxide.

  In addition to the vulcanizing agent, the rubber composition forming the intermediate rubber layer 4 can contain, for example, a vulcanization accelerator, a vulcanization aid, a vulcanization retarder, and the like.

  Examples of the vulcanization accelerator include aldehyde / ammonia, guanidine, thiourea, thiazole, sulfenamide, thiuram, and dithiocarbamate vulcanization accelerators.

  Examples of the vulcanization aid include zinc oxide, stearic acid, oleic acid, and zinc salts thereof.

  Examples of the adhesion improver include organic acid cobalt.

  The rubber composition forming the intermediate rubber layer 4 further includes reinforcing agents such as carbon black and silica, fillers such as calcium carbonate and talc, waxes such as microcrystalline wax, and oils such as aroma oil. , Polymers, anti-aging agents, antioxidants, pigments (dyes), plasticizers, thixotropic agents, UV absorbers, flame retardants, solvents, surfactants (including leveling agents), dispersants, dehydrating agents, One or more kinds of compounding agents such as a rust inhibitor, an adhesion-imparting agent, an antistatic agent and a processing aid can be blended.

  Examples of the carbon black include carbon black for rubber such as FEF, ISAF, and HAF.

  The average thickness t1 (including the steel cord) t1 of the intermediate rubber layer 4 is not particularly limited, and may be, for example, 2.5 mm or more and 20 mm or less. Further, the average distance t2 from the surface of the steel cord to the surface of the intermediate rubber layer 4 is not particularly limited, and can be, for example, 0.3 mm or more and 2.5 mm or less.

<Cover rubber layer>
The cover rubber layer 5 is laminated on the front and back surfaces of the intermediate rubber layer 4. As the base rubber of the rubber composition forming the cover rubber layer 5 and the compounding agent to be blended with the base rubber, the same rubber as the intermediate rubber layer 4 (but not including the adhesion improver) can be used.

  It does not specifically limit as average thickness of the cover rubber layer 5, For example, it is 3 mm or more and 30 mm or less.

[Belt connection method]
The belt connection structure 1 can be obtained by a belt connection method including the following steps.
(1) A step of extending a plurality of cords at a pair of opposite belt end portions 10a, 10b of the flat belt. (2) A plurality of cords extending to the pair of belt end portions 10a, 10b are formed as a long cord 2a, 2b and a step of forming the single short cords 3a and 3b having a shorter extension distance than the long cords 2a and 2b in a predetermined order (3) In the first transition region T1 on the one belt end 10a side, Bending the long cord 2a of the first cord group so as to shift to one side in the width direction, and bending the short cord 3a adjacent to one side in the width direction of the long cord 2a so as to shift to the other side in the width direction. (4) In the second transition region T2 on the other belt end 10b side, the long cord 2b of the second cord group is bent so as to shift to the other side in the width direction, and the other in the width direction of the long cord 2b. A step of bending the short cord 3b adjacent to the side so as to shift to one side in the width direction. (5) Matching the short cord 3a of the first code group with the short code 3b of the second code group, and the length of the first code group The step of juxtaposing the cord 2a with the long cord 2b of the second cord group (6) The step of arranging a rubber layer around the combined first cord group and second cord group (7) The intermediate rubber layer 4 and the cover rubber layer 5 forming step

<(1) Cord extension process>
In the cord extending step, the rubber layers at both belt end portions of the flat belt are removed, and a plurality of cords are exposed to extend from the belt end portions 10a and 10b. Specifically, the rubber layer at both ends of the flat belt is cut and peeled using a cutter knife or the like, and the residue of the rubber layer adhering to the peripheral surface of the cord is polished with sandpaper, a wire brush, etc. Remove with solvent. Note that the end of each steel cord, which tends to be the starting point of breakage of the joint, is not inclined at the right angle with respect to the longitudinal direction of the belt so that it does not simultaneously pass the position bent in the longitudinal direction on the pulley or roller. Is preferably formed.

<(2) Code group formation process>
In the cord group forming step, a first cord group in which the long cord 2a and the short cord 3a are alternately and continuously arranged from one belt end portion 10a is formed. Similarly, a second cord group in which the long cord 2a and the short cord 3a are alternately and continuously arranged from the other belt end portion 10b is formed. Specifically, among the cords exposed in the cord extending process, the short cords 3a and 3b are formed by cutting the tip of the cord every other cord, and the first cord group and the second cord group are formed. To do. When the rubber layers of the belt end portions 10a and 10b are cut while being inclined with respect to the longitudinal direction of the belt, the tip positions of the steel cords are set so that the protruding lengths of the long cords and the short cords are substantially equal to each other. Each cord is processed so as to be shifted in the longitudinal direction of the belt along the width direction of the belt.

<(3) First code bending step>
In the first cord bending step, in the first transition region T1 on the one belt end 10a side, the long cord 2a of the first cord group is bent so as to shift to one side in the width direction, and the short cord 3a is moved in the width direction. The long cord 2a and the short cord 3a are bent so as to be parallel to each other in the overlapping region J. Further, in the central transition region T3, the long code 2a of the first code group is bent so as to shift to one side in the width direction.

<(4) Second code bending step>
In the second cord bending step, in the second transition region T2 on the other belt end 10b side, the long cord 2b of the second cord group is bent so as to shift to the other side in the width direction, and the short cord 3b is moved in the width direction. The long cord 2b and the short cord 3b are bent in the overlapping region J so as to be parallel to each other. Further, in the central transition region T3, the long code 2b of the second code group is bent so as to be shifted to the other side in the width direction.

<(5) Code group placement step>
In the code group arranging step, the short code 3a of the first code group is matched with the short code 3b of the second code group, and the long code 2a of the first code group is juxtaposed with the long code 2b of the second code group. Place the code.

<(6) Rubber layer disposing step>
In the rubber layer disposing step, a rubber composition for forming the intermediate rubber layer 4 is disposed around the belt in the thickness direction and the width direction of the combined first cord group and second cord group. Specifically, a rubber composition sheet is formed which is filled with a rubber composition that forms an intermediate rubber layer 4 between cords, and then forms an intermediate rubber layer 4 on the front and back surfaces of a cord group filled with the rubber composition. Are further laminated. At this time, the adhesiveness between the cord and the intermediate rubber layer 4 can be enhanced by applying in advance a solution obtained by dissolving the rubber composition in a solvent on the peripheral surface of each cord.

<(7) Intermediate rubber layer and cover rubber layer forming step>
In the intermediate rubber layer and cover rubber layer forming step, a rubber composition for forming the cover rubber layer 5 is laminated on the front and back surfaces of the rubber composition disposed around the cord group, and these rubber compositions are vulcanized. Thus, the intermediate rubber layer 4 and the cover rubber layer 5 are formed. Thereby, the edge parts of a belt are connected and the connection structure 1 of the said belt is obtained.

〔advantage〕
The belt connection structure 1 is bent so that the long cord 2a of the first cord group is shifted to one side in the width direction and the short cord 3a is shifted to the other side in the width direction in the first transition region T1. In addition, in the second transition region T2, the long code 2b of the second code group is bent so as to shift to the other side in the width direction, and the short code 3b is bent so as to shift to one side in the width direction. Thereby, the connection structure 1 of the belt surely reduces the distance between adjacent cords extending from the same end portion in the overlapping region J while suppressing the uneven stress applied to the cords arranged in the width direction. it can. As a result, the belt connection structure 1 can reduce the shear stress at the connection portion of the belt and improve the connection strength.

  In the belt connection structure 1, the long cord 2a of the first cord group is bent so as to shift to one side in the width direction in the central transition region T3, and the long cord 2b of the second cord group is bent in the other direction in the width direction. It is bent to shift to the side. Thereby, since the stress concerning each cord arranged in parallel in the width direction is dispersed, the shear stress of the connecting portion of the belt is further reduced.

  In the first cord bending step, the belt is connected by bending the long cord 2a so as to shift to one side in the width direction, and then bending the adjacent short cord 3a with reference to the longitudinal direction of the belt. The short cord 3a can be easily positioned by bending the long cord 2a so as to be aligned with the position symmetrical with the long cord 2a. Similarly, in the second code bending step, it is easy to align the short code 3b after the long code 2b of the second code group is bent. Thereby, the working efficiency at the time of belt connection improves with the connection method of the said belt.

[Conveyor belt]
Since the belt connection structure 1 has a high connection strength with reduced shear stress as described above, a conveyor belt excellent in strength and durability can be obtained by using the belt connection structure 1.

[Other Embodiments]
The belt connection structure of the present invention is not limited to the above-described embodiment, and may be the following embodiment.

  In the above embodiment, the belt connecting structure in which the single long cord and the single short cord extend from the belt end has been described. However, the present invention is not limited to this configuration. A belt connecting structure in which a plurality of short cords with a short extension distance extend from the belt end, and the long cord and the plurality of short cords are arranged in the width direction in a predetermined order may be employed. As an example of this, FIG. 4 shows an embodiment of a belt connection structure 11 in which a plurality of short cords extend from the belt end.

  In the belt connection structure 11 shown in FIG. 4, a long cord 12a having a single length from one belt end 20a, a first short cord 13a having a shorter extension distance than the long cord 12a, and a first short cord 13a. Further, the second short cord 14a (first cord group) having a short extension length extends and is arranged in parallel so as to repeat this order from the other side in the width direction toward the one side. Also, a long cord 12b having a single length from the other belt end 20b, a first short cord 13b having a shorter extension distance than the long cord 12b, and a second short having a further extension distance shorter than the first short cord 13b. The code 14b (second code group) extends and is arranged in parallel so as to repeat in the opposite order from the first code group from the other side in the width direction toward the one side.

  Then, in the first transition region T1, the long cord 12a extending from the one belt end 20a is bent so as to shift to one side in the width direction, and the first adjacent to the one side in the width direction of the long cord 12a. The short cord 13a is bent so as to shift to the other side in the width direction. Similarly, in the second transition region T2, the long cord 12b extending from the other belt end 20b is bent so as to shift to the other side in the width direction, and the second cord adjacent to the other side in the width direction of the long cord 12b. 1 The short cord 13b is bent so as to shift to one side in the width direction. With this configuration, since the ineffective region I where the intermediate rubber layer 4 does not contribute to the improvement of the connection strength can be reduced as shown in FIG. 4, a high connection strength can be obtained by the belt connection structure 11. Further, in the first transition region T1, the long code 12a and the first short code 13a of the first code group are bent at substantially the same angle in the opposite direction of the width direction, and the length of the second code group in the second transition region T2. The cord 12b and the first short cord 13b are bent at substantially equal angles in the opposite direction of the width direction. Thereby, the bias of the stress applied to each cord in the width direction is reduced, and the shear stress of the connecting portion of the belt is reduced.

  In the belt connection structure 11 shown in FIG. 4, the second short cords 14a and 14b are not bent in the first transition region T1 and the second transition region T2. The region may be bent. Further, there may be more types of short cords extending from one and the other belt end. In other words, the belt may be configured such that three or more types of short cords having different extension distances extend from one and the other belt end.

  Further, the belt connection structure 1 in FIG. 2 has a central transition region for bending the long cord at a substantially central portion in the longitudinal direction of the overlapping region J, but the belt connection structure 11 in FIG. Thus, a belt connection structure that does not have a central transition region is also within the intended scope of the present invention. Further, a plurality of central transition regions may be provided between the first transition region T1 and the second transition region T2. By having a plurality of central transition regions, the cords can be bent more in the overlapping region, so that the distance between the cords in the width direction in the overlapping region can be easily adjusted.

  In the above embodiment, the belt connection structure that bends the cords of the first cord group and the second cord group in both the first transition region T1 and the second transition region T2 has been described. The belt connection structure in which the cord is bent only in one transition region is also within the intended scope of the present invention. For example, a belt connection structure in which the cords of the second cord group are not bent in the second transition region T2 and only the cords of the first cord group are bent in the first transition region T1 may be employed. Even in this case, the stress applied to each cord of the first cord group is evenly distributed, and the invalid area I formed between the cords of the first cord group is reduced and the connection strength is improved. In addition, since it is predicted that a greater stress is applied to the rear side in the running direction of the belt than the front side at the connecting portion, when the cord is bent only in one transition area of the pair of transition areas, the belt It is preferable to bend the cord in the transition region on the rear side in the traveling direction.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

[Example 1]
A flat belt with a belt strength of 2100 N / mm and a width of 278.2 mm in which 19 steel cords with a diameter of 5.8 mm are embedded at a pitch of 14.2 mm (distance between cord axes) and the steel cord is extended at both ends thereof. I made it come out. Next, the number of cords is different from that in Fig. 2, but as shown in Fig. 2, long cords and short cords are formed so that long cords and short cords continue alternately from both ends, and the short cords from both ends are matched. The long cord and the short cord were bent in the first transition region T1 and the second transition region T2. Here, the length of each transition region T1, T2 in the longitudinal direction was 100 mm, and the inclination angle of each cord to be bent was about 2.1 °. Thereafter, a rubber composition in which sulfur, a vulcanization accelerator, a vulcanization acceleration aid, stearic acid, cobalt organic acid, carbon black, aroma oil, and an antioxidant are added to a rubber component composed of natural rubber and styrene butadiene rubber. Was filled between the cords, and this rubber composition was laminated on the front and back surfaces of the cord group. Next, on the front and back surfaces of the laminated rubber composition, sulfur, a vulcanization accelerator, a vulcanization acceleration aid, stearic acid, carbon black, aroma oil and aging are applied to the rubber component made of natural rubber and styrene butadiene rubber. A rubber composition to which an inhibitor is added is further laminated and vulcanized to obtain an intermediate rubber layer (distance from the steel cord surface to the intermediate rubber layer surface: 0.3 mm), an upper cover rubber layer (thickness: 6 mm), and A lower cover rubber layer (thickness: 6 mm) was formed, and both ends of the flat belt were connected to obtain an endless conveyor belt having a total length of 6 m in Example 1.

[Comparative Example 1]
The same flat belt as in Example 1 was used, and long cords and short cords were formed so that long cords and short cords continued alternately from both ends as in Example 1. Next, although the number of cords is different from that in FIG. 7, the short cords from both ends are abutted as shown in FIG. 7, and the short cords are not bent and only the long cords are converted into the first transition region T1 and the second transition region T2. It was bent with. The length of each transition region T1, T2 in the longitudinal direction was 100 mm, and the inclination angle at which the long cord was bent was about 2.7 °. Thereafter, an intermediate rubber layer and a cover rubber layer were formed in the same manner as in Example 1, and both ends of the flat belt were connected to obtain an endless conveyor belt having a total length of 6 m of Comparative Example 1. The conveyor belt of Comparative Example 1 is a conventional conveyor belt having a connection structure shown in FIG.

[Evaluation of connection structure]
About the conveyor belt of Example 1 and Comparative Example 1, the average interval Zn in the width direction of adjacent cords extending from the same end portion in the overlapping region J and adjacent in the extending width direction from different ends in the overlapping region J The average distance Zw in the width direction of the cord to be measured was measured.

  In the conveyor belt of Example 1, the average interval Zn was 1.0 mm, and the average interval Zw was 5.0 mm. On the other hand, the average interval Zn and the average interval Zw of the conveyor belt of Comparative Example 1 were equal to 3.67 mm. From this result, the ineffective area I which does not contribute to the shearing of the rubber layer is smaller in Example 1 than in Comparative Example 1, and the connection strength of the connection portion of the conveyor belt of Example 1 is predicted to be higher. Is done.

[Stress evaluation]
The conveyor belts of Example 1 and Comparative Example 1 were cut at portions other than the connection structure so that the belt connection structure was located at the center, and the stress of each cut belt was measured as follows. That is, the belt was wound so that the belt was in contact with the circumferential surface of 1/4 turn from the pull start point of the pulley having a diameter of 1250 mm so that one of the belts was in the vertical direction and the other was in the horizontal direction. From the state in which the majority of the belt is in the vertical direction, a load is applied to the end on the vertical direction, one end on the horizontal direction is pulled in the horizontal direction with a tension of 269 kN, and the connecting structure portion of the belt contacts the pulley The belt was moved 5 m to pass. The Mises stress concerning the rubber layer, the long cord, and the short cord at this time was measured. The measurement results of the Mises stress of the belts of Example 1 and Comparative Example 1 are shown in FIGS. 5 (a) and 5 (b). 5A and 5B, the maximum value of the Mises stress applied to the entire long cord is indicated by a solid line, and the maximum value of the Mises stress applied to the entire short cord is indicated by a broken line. The maximum value of the Mises stress of the long cord indicated by the solid line is obtained by plotting the largest stress value among the stress values generated in all the long cords against the moving distance of the belt from the pulley and connecting them. . Similarly, the maximum value of the Mises stress of the short cord indicated by the broken line is plotted by connecting the maximum stress values among the stress values generated in all the short cords against the moving distance of the belt from the pulley. Is.

  From the results of FIG. 5A and FIG. 5B, when the same external force is applied, the maximum value of stress applied to the short cord and the long cord is lower in Example 1 than in Comparative Example 1. It could be confirmed. In particular, when the maximum stress applied to the long cord is compared, it is about 6200 MPa in Comparative Example 1 and about 4900 MPa in Example 1, and it can be seen that the stress applied to each cord is much smaller in Example 1. Thereby, it can be estimated that the belt of Example 1 is harder to break than the belt of Comparative Example 1.

  Further, as shown in FIGS. 5A and 5B, the maximum value of the Mises stress applied to the entire long cord is generally larger than the maximum value of the Mises stress applied to the entire short cord. When the difference Sd between the maximum value of the Mises stress applied to the entire long cord and the maximum value of the Mises stress applied to the entire short cord is compared in Example 1 and Comparative Example 1, the maximum value of the difference Sd in Comparative Example 1 is about 1600 MPa. On the other hand, the maximum value of the difference Sd in Example 1 was about 900 MPa. Accordingly, it can be seen that the difference between the stress applied to the long cord and the stress applied to the short cord is smaller in Example 1 than in Comparative Example 1, and in Example 1, the stress is more evenly distributed. Therefore, it is considered that the belt of Example 1 is more difficult to break than the belt of Comparative Example 1 and has excellent durability.

  The belt connection structure, belt conveyor, and belt connection method of the present invention can improve the connection strength between cords extending from a pair of belt end portions easily and reliably, and is therefore suitable for a belt for transporting deposits and the like. Can be used.

1, 11 Belt connection structure 2a, 2b, 12a, 12b Long cord 3a, 3b Short cord 4 Intermediate rubber layer 5 Cover rubber layer 10a, 10b, 20a, 20b Belt end 13a, 13b First short cord 14a, 14b First 2 Short cord 101 Laminated body 102 Cord 102a Short cord 102b Long cord 103 Intermediate rubber layer 104 Cover rubber layer B cord J Overlapping area T1 1st transition area T2 2nd transition area T3 Central transition area I Invalid area

Claims (8)

Arranged between a pair of opposite ends of a flat belt in which a plurality of cords are embedded in the longitudinal direction,
One cord group in which a single long cord extending from one end and a single cord or a plurality of short cords having a shorter extension distance than the long cord are arranged in parallel in a predetermined order in the width direction;
The other cord group in which the long cord and the short cord extending in the same manner from the other end are parallel in the width direction in the opposite order to the one cord group;
A belt connection structure comprising: a combined rubber cord around the one cord group and the other cord group;
In the longitudinal direction between the pair of end portions, the short cord of the one cord group is abutted with the short cord of the other cord group, and the long cord of the one cord group is juxtaposed with the long cord of the other cord group. And a pair of transition regions that are formed between both ends of the overlap region and the pair of end portions and shift the position in the width direction of each cord of one cord group and the other cord group. And
In this transition region on one end side, the long cord of one cord group is bent so as to shift to one side in the width direction, and the short cord adjacent to one side in the width direction of this long cord is connected to the other in the width direction. A belt connecting structure characterized in that it is bent so as to shift to the side.   2. The belt connection structure according to claim 1, wherein the long cord and the short cord in the one cord group and the other cord group are alternately continued.   3. The belt connection structure according to claim 1, wherein an average interval in the width direction in the overlapping region of the long cord and the short cord shifted so as to approach each other in the overlapping region is 0.1 mm or more and 2 mm or less.   4. The belt connection structure according to claim 1, wherein an average inclination angle of the long cord and the short cord in the pair of transition regions is 1.5 ° or more and 2.5 ° or less. 5.   The long cord of one cord group is bent so as to shift to one side in the width direction at the substantially central portion in the longitudinal direction of the overlapping region, and the long cord of the other cord group is shifted to the other side in the width direction. The belt connection structure according to any one of claims 1 to 4, further comprising a central transition region to be bent.   The belt connecting structure according to any one of claims 1 to 5, wherein the cord is a steel cord.   A conveyor belt provided with the connection structure of the belt of any one of Claims 1-6. Extending a plurality of cords at a pair of opposite ends of a flat belt having a plurality of cords embedded in the longitudinal direction;
Forming a plurality of cords extending to the pair of ends into a long cord and a single cord or a plurality of short cords having a shorter extension distance than the long cord in a predetermined order;
In this transition region on one end side, the long cord of one cord group is bent so as to shift to one side in the width direction, and the short cord adjacent to one side in the width direction of this long cord is connected to the other in the width direction. Bending to shift to the side,
Matching the short code of one code group with the short code of the other code group, juxtaposing the long code of one code group with the long code of the other code group;
And a step of disposing a rubber layer around the one cord group and the other cord group in combination.

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