JP2008169022A - Conveyor belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conveyor belt relaxing stress concentration generated at an intersection between a warp and a weft of a core canvas of a plain weaving structure when applying tension to the conveyor belt, and suppressing degradation in strength of the warp sustaining tension. <P>SOLUTION: When tension in a longitudinal direction is applied to the conveyor belt 1, the warp 3 of the core canvas 2 of the plain weaving structure linearly extends and push-presses at the intersection, the weft 4 having intermediate elongation of not less than 10% nor more than 18% under a load of one-tenth of the tensile tenacity at break. Thereby, the weft 4 appropriately extends to relax stress concentration generated in the warp 3 by pressure contact with the weft 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a conveyor belt. More specifically, the present invention relates to the strength of a warp that bears tension by relaxing stress concentration generated at the intersection of warp and weft of a plain weave structure when a tension is applied to the conveyor belt. The present invention relates to a conveyor belt that suppresses the decrease.

  The plain canvas fabric, which is frequently used for conveyor belts, has a simple structure in which warp yarns and weft yarns are alternately crossed, so that productivity is high and costs can be reduced. However, in a conveyor belt using a plain weave structure core canvas, when a tension is applied in the longitudinal direction, the parallel weft yarns and the warp yarns intersecting with each other in an up and down direction press the weft yarns at the intersections. Therefore, the warp and the weft are brought into pressure contact with each other, and excessive stress is generated due to the stress concentration, and the warp that bears the tension has a problem that it does not fully exhibit the inherent tensile strength and breaks.

The extent to which the tensile strength inherent in the warp can be expressed is represented by the strength utilization factor F in the longitudinal direction of the canvas calculated by the following equation (1), and it is desirable to increase this numerical value F.
Tensile strength utilization factor F = (longitudinal breaking strength per unit width of core canvas / (tensile breaking strength of one warp × number of warps per unit width)) × 100% (1)

Various conveyor belts using a plain weave structure core canvas have been proposed (for example, Patent Documents 1 and 2), but no investigation has been made to improve the strength utilization factor F in the vertical direction of the canvas. As shown in FIG. 4, if the core canvas 2 has a unicon woven structure, the warp yarns 3 and the weft yarns 4 intersect each other in a straight line without undulating up and down. Therefore, even when tension is applied to the conveyor belt 1, the warp yarn 3 and the weft yarn 4 are not strongly pressed against each other at the intersection. Therefore, the breaking strength of the warp yarn 3 is sufficiently exhibited without stress concentration at the intersection, and the strength utilization factor F in the longitudinal direction of the canvas can be improved. However, the core canvas 2 requires a special material such as a binder 6 for bonding the warp yarn 3 and the weft yarn 4 and has a complicated structure, resulting in a decrease in productivity. 2 and the cost of the conveyor belt 1 are increased.
Japanese Utility Model Publication No. 63-171707 Japanese Patent Laid-Open No. 5-24703

  It is an object of the present invention to alleviate stress concentration generated at the intersection of warp and weft of a plain weave structure core fabric when tension is applied to the conveyor belt, and to suppress a reduction in strength of the warp that bears the tension. It is to provide a conveyor belt.

  In order to achieve the above object, a conveyor belt according to the present invention is a conveyor belt provided with a plain canvas-structured core canvas, and the weft of the core canvas arranged in the belt width direction has a tensile breaking strength of 1 of the weft. The intermediate elongation at / 10 load is 10% or more and 18% or less.

  According to the conveyor belt of the present invention, as the weft of the core canvas, the weft having an intermediate elongation of 10% or more and 18% or less at a load of 1/10 of the tensile breaking strength of the weft is used. When the tension in the direction is applied, the weft yarn is pressed at the intersection by the warp yarn which is intended to be linear, and can be extended appropriately. Thereby, the stress which arises by the mutual press-contact in the cross | intersection part of a warp and a weft is relieved, and an excessive stress does not generate | occur | produce in a warp. Therefore, the warp yarn can bear the tension without damaging the inherent tensile strength. Along with this, the strength in the longitudinal direction (longitudinal direction) of the conveyor belt is increased and the weft yarn is not easily broken, so that the durability of the conveyor belt is improved.

  Further, since the core canvas is kept in a simple plain weave structure without making it a complicated structure, the productivity of the core canvas is high, and the costs of the core canvas and the conveyor belt can be reduced.

  Hereinafter, the conveyor belt of the present invention will be described based on the embodiments shown in the drawings.

  As shown in FIG. 1, the conveyor belt 1 of the present invention has a structure in which rubber layers 5 are laminated on both surfaces of a single core canvas 2. The core canvas 2 has a plain weave structure in which warp yarns 3 and weft yarns 4 alternately intersect, and the warp yarns 3 are arranged in the longitudinal direction of the conveyor belt 1 and the weft yarns 4 are arranged in the width direction of the conveyor belt 1.

  In a state in which no tension is applied to the conveyor belt 1, the warp yarn 3 of the core canvas 2 intersects with the weft yarn 4 in parallel and undulates in the length direction of the yarn as illustrated in FIGS. It has become. The weft 4 is also wavy in the length direction of the yarn by crossing the warp yarn 3 in parallel with the upper and lower sides. When tension is applied in the longitudinal direction by placing the conveyor belt 1 between pulleys, as shown in FIG. 3, the waving warp 3a extends in a straight line and presses the wefts 4a, 4b, 4c arranged in parallel at the intersection. .

  In the present invention, the weft yarn 4 is used whose intermediate elongation at 1/10 load of the tensile breaking strength of the weft yarn 10 is 10% or more and 18% or less. Thus, the weft 4 has an elongation of 10% or more at a stage where the tensile force is small and has a specification with a large initial elongation. Therefore, when the conveyor belt 1 is loaded with a tension, the warp is going to be linear. 3 is pressed and can be extended moderately. Therefore, the stress concentration due to the pressure contact between the warp yarn 3 and the weft yarn 4 at the intersection is alleviated, and it is possible to prevent an excessive stress from being generated in the warp yarn 3 and the weft yarn 4.

  In this way, in the conveyor belt 1 of the present invention, excessive stress is not generated in the warp yarn 3, so that the decrease in tensile strength is suppressed, and the tension applied to the conveyor belt 1 can be borne so as not to impair the tensile strength that it originally has. it can. Therefore, the numerical value of the strong utilization factor F in the vertical direction of the canvas calculated by the above equation (1) is also improved. That is, even the core canvas 2 having a plain weave structure can be used to reduce the loss of tensile strength of each warp yarn 3 and bear the tension applied to the conveyor belt 1. Therefore, the core canvas 2 is hardly broken and the strength in the longitudinal direction (longitudinal direction) of the conveyor belt 1 is increased, so that the durability of the conveyor belt 1 is improved.

  When the intermediate elongation at 1/10 load of the tensile breaking strength of the weft 4 is less than 10%, the elongation when pressed against the warp 3 is small, and the stress concentration at the intersection of the warp 3 and the weft 4 is reduced. It cannot be relieved, and the strength reduction of the warp 3 cannot be sufficiently suppressed. Further, if the intermediate elongation exceeds 18%, the elongation when pressed by the warp 3 becomes too large, the rigidity in the width direction of the conveyor belt 1 is insufficient, and when the core canvas 2 is woven. In addition, the fluctuation of the width becomes large, which causes a decrease in productivity.

  In the present invention, since the core body canvas 2 having a plain structure and high productivity is used, the cost of the core body canvas 2 and the conveyor belt 1 can be reduced. Furthermore, since the strength utilization factor F in the longitudinal direction of the canvas is improved, it is possible to reduce the number of warps 3 to be driven as compared to the conventional one, and the conveyor belt 1 is lighter and more flexible, thereby reducing the operating energy. Contribute.

  The warp 3 is made of a general material used for the core canvas 2 of the conveyor belt 1 and is a material that can bear the tension applied to the conveyor belt 1 and has a low elongation of high tension, such as aramid fiber, nylon fiber, polyester. (PET) fiber or the like is used.

  The weft 4 is made of a material having a large initial elongation, such as polybutylene terephthalate (PBT) fiber or polytrimethylene terephthalate (PTT) fiber, whose intermediate elongation at 1/10 load of tensile breaking strength is 10% or more and 18% or less. Is used.

  A plurality of core canvases 2 may be laminated on the conveyor belt 1, or a structure in which a reinforcing layer is laminated may be employed. When the core canvas 2 exemplified in the embodiment is a single-layer conveyor belt 1, the elongation of the weft 4 pressed by the warp 3 is not easily restricted by other components, so the strength utilization factor F in the vertical direction of the canvas is It can be improved further.

  The test sample of the conveyor belt (size: upper layer rubber thickness 2 mm, lower layer rubber thickness 1 mm) having one layer of core canvas as shown in FIG. 1 is changed as shown in Table 1 only for the specifications of the core canvas. 7 types (Examples 1 to 3, Comparative Examples 1 to 4) were prepared and subjected to a tensile test to obtain a longitudinal breaking strength B and a transverse breaking strength B2 per unit width of the core canvas of each test sample. It was measured.

  In addition, the canvas tensile test sample was made into a strip shape with a width of 25 mm, and the obtained data was converted into data per unit width (per cm). The rubber of the rubber layer was all NR (natural rubber) / SBR.

  Further, the tensile elongation at break B1 of the warp yarn of each test sample and the intermediate elongation L1 when a tensile load of 1/10 of the tensile breaking strength B1 is applied, the tensile breaking strength B3 and the tensile breaking strength B3 of the weft Table 1 shows the results of measuring the intermediate elongation L2 when a tensile load of 1/10 is applied, and evaluating the measurement results and the belt longitudinal strength level and core canvas productivity for each test sample. The strong utilization factor F in Table 1 is the strong utilization factor F in the vertical direction of the canvas calculated from the above equation (1) using measurement data.

  The tensile test method (measurement of B value and B2 value) of the core canvas conforms to JIS K6322-1998, and the rubber layers covering the upper and lower surfaces of the core canvas are left slightly on the core canvas layer. A tensile test was performed after slicing to a thin thickness. Further, the warp / weft tensile test (measurement of B1 value and B3 value) was carried out in accordance with JIS L1017 by taking out only the yarn from the core canvas layer.

[Belt longitudinal strength level]
When the strength utilization factor F in the longitudinal direction of the canvas calculated by the above formula (1) using the measurement data is 80% or more, the warp yarn is evaluated as being able to sufficiently exert the tensile strength, and is indicated by ◯. Is indicated by x.

[Mental canvas productivity]
Based on the productivity of the core canvas of Comparative Example 1, the case of having the same productivity is indicated by ◯, and the case of inferiority is indicated by ×.

  From the results shown in Table 1, in Examples 1 to 3, in which the intermediate elongation at the time of 1/10 load of the tensile breaking strength was within the range specified by the present invention (10% to 18%), the warp longitudinal strength was determined. It was confirmed that the utilization factor F could be increased to 80% or more, and the same performance as that of Comparative Example 2 using the unicon woven core canvas was obtained. Moreover, it has confirmed that the core canvas of Examples 1-3 has productivity equivalent to the comparative example 1 which is a core canvas of a general plain weave structure.

It is a partially cutaway perspective view illustrating the structure of the conveyor belt of the present invention. It is an A arrow directional view which shows typically the core body canvas of FIG. It is a schematic diagram which shows the state which applied tension | tensile_strength to the core canvas of FIG. It is a perspective view which illustrates the unison woven core canvas.

Explanation of symbols

1 Conveyor Belt 2 Core Canvas 3, 3a, 3b, 3c, 3d, 3e Warp Yarn 4, 4a, 4b, 4c Weft 5 Rubber Layer 6 Binder

Claims (3)

  In a conveyor belt provided with a core canvas of a plain weave structure, the weft of the core canvas arranged in the belt width direction has an intermediate elongation of 10% or more at 1/10 load of the tensile breaking strength of the weft. % Or less conveyor belt.   The conveyor belt according to claim 1, wherein the weft is made of polybutylene terephthalate or polytrimethylene terephthalate.   The conveyor belt according to claim 1 or 2, wherein the number of layers of the core canvas is one layer.

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