JP7059523B2 - Conveyor belt joining method - Google Patents

Description

The present invention relates to a method for joining a conveyor belt, and more specifically, it is possible to improve the adhesiveness between the rubber and the fiber reinforcing layer when the rubber and the fiber reinforcing layer are peeled off in the width direction of the conveyor belt. It relates to a method of joining a conveyor belt.

In order to make the band-shaped conveyor belt 1 annular, so-called endless processing is performed. In endless processing, the cover rubber is removed at the longitudinal end of each belt to be joined. In a conveyor belt in which a fiber reinforcing layer is used as the core body, some rubber components (adhesive rubber that adheres the cover rubber and the fiber reinforcing layer, etc.) remain on the surface of each fiber reinforcing layer during endless processing. The remaining rubber components are vulcanized by interposing a vulcanizing adhesive or the like to join the ends in the longitudinal direction of the belt (see, for example, Patent Document 1).

To remove the cover rubber laminated and joined to the fiber reinforced layer, a cut is made in the cover rubber, and the cover rubber is peeled off from the fiber reinforced layer using the cut as a starting point. There is no problem when the cover rubber is peeled off in the longitudinal direction of the conveyor belt (hereinafter referred to as the belt longitudinal direction) in the endless process, but it is peeled off in the width direction of the conveyor belt (hereinafter referred to as the belt width direction). In this case, in the specification where the conveyor belt is overvulcanized, the amount of the rubber component remaining on the surface of the fiber reinforcing layer from which the cover rubber is peeled off may be too small or may not remain at all. If the residual amount of the rubber component is too small, the belt longitudinal end portions cannot be firmly joined to each other, and if the rubber component does not remain, the belt longitudinal direction ends cannot be joined to each other.

The inventor of the present application has investigated the cause of the rubber component not remaining on the surface of the fiber reinforced layer when the cover rubber is peeled off in the belt width direction, and studied various means for eliminating this cause. It led to the creation of the invention.

Japanese Unexamined Patent Publication No. 2014-37280

An object of the present invention is to provide a method for joining a conveyor belt capable of improving the adhesiveness between the rubber and the fiber reinforcing layer when the rubber and the fiber reinforcing layer are peeled off in the belt width direction. ..

In order to achieve the above object, in the method of joining the conveyor belt of the present invention, a fiber reinforcing layer for a conveyor belt having a woven structure in which warp threads extend in the longitudinal direction of the belt and weft threads extend in the width direction of the belt is embedded as a core body. In the method of joining the conveyor belt, the ratio A1 / A2 of the exposed area A1 of the warp to the exposed area A2 of the weft is set to 3.0 or more and 5.0 or less in the plan view of the fiber reinforcing layer. At one end and the other end of the conveyor belt in the longitudinal direction, a cut is made in the cover rubber and the cover rubber is peeled off from the fiber reinforcing layer using the cut as a starting point, and the warp is extended in the warp. The cover rubber is peeled off from the fiber reinforcing layer in the belt width direction so that a peeling force in a direction orthogonal to the direction acts to remove the cover rubber, and the one end and the other end after the cover rubber is peeled off. A rubber component is left on the surface of the fiber reinforcing layer of the portion, and each of the fiber reinforcing layers is laminated and smelted with a sulphurizing adhesive interposed between the remaining rubber components. It is characterized in that one end portion and the other end portion are joined by joining the facing surfaces of the fiber reinforcing layer to each other.

In the present invention , for example , the fiber reinforcing layer for a conveyor belt is embedded as at least the uppermost layer and the lowest layer of the core body.

According to the present invention, the ratio A1 / A2 of the exposed area A1 of the warp and the exposed area A2 of the weft is set to 3.0 or more and 5.0 or less in the plan view of the fiber reinforcing layer. Has been done. By setting this ratio A1 / A2 lower than before, when the rubber and the fiber reinforcing layer are peeled off in the belt width direction, the filament constituting the warp is pulled by the rubber and opened. Is less likely to occur. Along with this, the destruction of the filament portion of the warp is suppressed, and the adhesive layer adhering to the surface of the fiber reinforcing layer becomes difficult to separate from the warp. Therefore, the adhesiveness between the rubber and the fiber reinforcing layer can be improved as compared with the conventional case.

When the rubber is peeled off in the longitudinal direction of the belt, the ratio A1 / A2 is set to 3.0 or more, so that the filament constituting the weft is not pulled by the rubber and becomes excessively open. .. Therefore, regardless of the direction in which the rubber is peeled off, the rubber component can be appropriately left on the surface of the fiber reinforcing layer. Therefore, by vulcanizing by interposing a vulcanizing adhesive or the like between the remaining rubber components of the belt longitudinal end portions, the belt longitudinal end portions can be firmly joined to each other.

It is a horizontal view which illustrates the conveyor belt in which the fiber reinforcement layer for a conveyor belt used in this invention is embedded. It is explanatory drawing which illustrates the conveyor belt of FIG. 1 in a plan view. It is explanatory drawing which illustrates the state in which the conveyor belt of FIG. 1 is stretched between pulleys. FIG. 3 is a cross-sectional view taken along the line XX of FIG. It is explanatory drawing which enlarges and exemplifies the fiber reinforcement layer of FIG. 1 in a plan view. It is explanatory drawing which illustrates the process of peeling off the cover rubber of FIG. 1 in the cross-sectional view. It is explanatory drawing which illustrates the process of joining the fiber reinforcement layer which left the rubber component on the surface in the cross-sectional view from the side. It is explanatory drawing which illustrates the state which joined the fiber reinforcement layer of FIG. 7 by the cross-sectional view from the side. It is explanatory drawing which magnifies and schematically illustrates the state of the fiber reinforcement layer in the step of peeling off a cover rubber in a plan view. It is explanatory drawing which expands and schematically exemplifies another embodiment of a fiber reinforced layer in a plan view.

Hereinafter, the method of joining the conveyor belt of the present invention will be described based on the embodiment shown in the figure.

In the conveyor belt 1 used in the present invention exemplified in FIGS. 1 and 2, the fiber reinforcing layer 3 for the conveyor belt of the present invention (hereinafter referred to as the fiber reinforcing layer 3) is embedded as the core body 2. The core body 2 is a member that bears the tension generated in the stretched conveyor belt 1. Adhesive rubber is attached to the surface of the fiber reinforcing layer 3, and cover rubbers 6 are arranged above and below the core body 2, respectively. The core body 2 and the cover rubber 6 are integrated by vulcanization adhesion. The heart body 2 is continuous in the longitudinal direction of the belt, and the dimension in the width direction is slightly smaller than the width of the belt. As a result, both ends of the conveyor belt 1 in the width direction are made of ear rubber in which the core body 2 does not exist. The arrow L in the figure indicates the longitudinal direction of the belt (longitudinal direction of the conveyor belt 1), and the arrow W indicates the width direction of the belt (width direction of the conveyor belt 1).

The conveyor belt 1 in which the ends in the longitudinal direction are joined to form an annular shape is used by being stretched between the pulleys 8a and 8b as illustrated in FIGS. 3 and 4. Then, on the transport side on which the transport object 10 is placed and carried, the lower surface of both ends in the belt width direction is supported by the support roller 9 whose rotation axis is inclined at a predetermined angle a with respect to the horizontal, and the rotation axis is supported at the center portion in the belt width direction. The lower surface is supported by the horizontal support roller 9. As a result, both ends in the belt width direction are bent upward with respect to the central portion in the belt width direction, and the conveyor belt 1 is used in a trough shape. When bending around the pulleys 8a and 8b, the largest tensile stress is generated in the fiber reinforcing layer 3 arranged on the outermost circumference of the annular conveyor belt 1, and the largest on the fiber reinforcing layer 3 arranged on the innermost circumference. Compressive stress is generated.

In this embodiment, the core body 2 has a structure in which four fiber reinforcing layers 3 are laminated. The mind body 2 is not limited to a four-layer structure, but may have a single-layer structure or another multi-layer structure.

As illustrated in FIG. 5, in the fiber reinforcing layer 3, the warp 4 extends in the longitudinal direction of the belt, the weft 5 extends in the width direction of the belt, and the warp 4 and the weft 5 intersect each other vertically. It has a plain weave structure. The fiber reinforcing layer 3 is embedded with the extending direction of the warp 4 in the longitudinal direction of the belt.

For the warp 4, a multifilament yarn formed by twisting a plurality of filaments is used. For the weft 5, a multifilament yarn or a monofilament yarn formed by twisting one filament is used. The warp and weft 5 may be made of the same material or different materials. For example, polyester fiber is used for the warp 4, and for example, polyamide fiber is used for the weft 5. Examples of the polyamide fiber include nylon 6, nylon 66 and the like.

The present invention is characterized in that the ratio A1 / A2 of the exposed area A1 of the warp 4 to the exposed area A2 of the weft 5 is set to 3.0 or more and 5.0 or less in the plan view of the fiber reinforcing layer 3. There is one. The exposed area A1 of the warp 4 is an area excluding a portion covered with the weft 5 in a plan view and not visible. The exposed area A2 of the weft 5 is an area excluding a portion covered with the warp 4 in a plan view and not visible. In FIG. 5, the region of the exposed area A1 is shown by the diagonal line of the alternate long and short dash line, and the region of the exposed area A2 is shown by the diagonal line of the broken line.

It is important to ensure sufficient strength in the longitudinal direction of the belt in the fiber reinforced layer. Therefore, the warp and weft are generally thicker than the weft, and conventionally, the ratio A1 / A2 is, for example, 5.3 or more. On the other hand, the fiber reinforcing layer 3 of the present invention has a smaller ratio A1 / A2 than the conventional one. That is, in the present invention, the exposed area A1 of the warp 4 is smaller than that of the conventional fiber reinforcing layer.

When the conveyor belt 1 is made into an annular shape, the longitudinal end portions 1a of the strip-shaped conveyor belt 1 are joined by endless processing. In the endless processing, a cut is made in the cover rubber 6, and the cover rubber 6 is peeled off from the fiber reinforced layer 3 at the start of the cut. The cover rubber 6 is peeled off in the belt width direction as illustrated in FIG.

When the core body 2 is composed of a plurality of fiber reinforcing layers 3, the cover rubber 6 is removed from each longitudinal end portion 1a as illustrated in FIG. 7, and the fiber reinforcing layer 3 is formed into a step shape. The laminated fiber reinforcing layers 3 are separated from each other in the belt width direction. In this peeling operation, the adhesive rubber between the fiber reinforcing layers 3 and the fiber reinforcing layer 3 are peeled off in the belt width direction. A small amount of rubber component R (adhesive rubber or the like) remains on the surface of the fiber reinforcing layer 3 after the peeling operation.

Next, as illustrated in FIG. 8, the vulcanization adhesive 7 is applied to the surface of the remaining rubber component R of each belt longitudinal end portion 1a. Then, by vulcanizing with the vulcanizing adhesive 7 or the like interposed between the rubber components R, the facing surfaces of the laminated fiber reinforced layers 3 are joined to each other. As a result, the end portions 1a in the longitudinal direction of the belt are joined to each other to form an annular conveyor belt 1.

During the above-mentioned peeling operation, the peeling force f acts on the warp 4 as illustrated in FIG. Therefore, due to this peeling force f, the space between the filaments 4a constituting the warp 4 becomes wide and the filaments 4a are opened. The extending direction of the weft 5 is substantially orthogonal to the extending direction of the warp 4. Therefore, even if the peeling force f acts on the weft 5, the filament 5a constituting the weft 5 does not become open like the filament 4a constituting the warp 4.

According to the inventor of the present application, when the filament 4a is opened, the filament 4a portion is easily broken, and the adhesive layer adhering to the filament 4a is integrated and adhered to the peeled cover rubber 6 side. It has been found that this makes it difficult for the rubber component R to remain on the surface of the fiber reinforcing layer 3. Therefore, based on this finding, in the fiber reinforcing layer 3 used in the present invention, the above-mentioned ratio A1 / A2 is set to 5.0 or less as compared with the conventional one.

By reducing the ratio A1 / A2, the area of the warp 4 on which the peeling force f directly acts is reduced. Therefore, even if the same peeling force f acts, the filament 4a of the warp 4 is less likely to be opened, and the rubber component R is likely to remain on the surface of the fiber reinforcing layer 3. As a result, even when the rubber is peeled off in the belt width direction, the laminated fiber reinforcing layers 3 can be firmly joined to each other, and the longitudinal end portions 1a can be firmly joined to each other. It will be possible.

When the ratio A1 / A2 is less than 3.0, when the rubber is peeled off in the longitudinal direction of the belt, if the weft 5 is a multifilament yarn, the filament 5a is opened due to the peeling force at that time. It is easy to get into a state. As a result, the rubber component R is less likely to remain on the surface of the fiber reinforcing layer 3. Therefore, in the present invention, the ratio A1 / A2 is set to 3.0 or more and 5.0 or less.

INDUSTRIAL APPLICABILITY The present invention provides a useful solution to a new problem that occurs when a rubber such as a cover rubber 6 is peeled off in the belt width direction, that is, a problem that has not been conventionally paid attention to when performing endless processing. There is. Moreover, a sufficient amount of rubber component is present on the surface of the fiber reinforced layer 3 after the peeling work, both when the rubber is peeled off in the longitudinal direction of the belt and when the rubber is peeled off diagonally with respect to the longitudinal direction of the belt. R remains, and it is possible to firmly join the end portions 1a in the longitudinal direction to each other.

In order to reduce the ratio A1 / A2, specifically, the warp 4 is made thinner (the fineness F1 of the warp 4 is made smaller), the arrangement density of the warp 4 is made smaller, and the weft 5 is made thicker (the fineness F2 of the weft 5 is made smaller). There are options such as increasing the arrangement density of the weft 5) and increasing the arrangement density of the weft 5. When the warp 4 is made too thin or the arrangement density of the warp 4 is made too small, there arises a problem that it becomes difficult to secure the strength of the fiber reinforcing layer 3 in the belt longitudinal direction. On the other hand, when the weft 5 is made too thick or when the arrangement density of the warp 4 is made too small, the crimp ratio (the degree of vertical bending) of the warp 4 increases. Along with this, the stretched conveyor belt 1 has a large elongation over time, which causes problems such as the conveyor belt 1 tending to meander. Therefore, the fineness F1 and the arrangement density of the warp 4 and the fineness F2 and the arrangement density of the weft 5 are set in an appropriate range according to the usage conditions of the conveyor belt 1 and the like.

Therefore, it is preferable to set the ratio F1 / F2 of the fineness F1 of the warp 4 to the fineness F2 of the weft 5 to 1.5 or more and 2.5 or less. When the ratio F1 / F2 is less than 1.5, the crimp ratio of the warp 4 tends to be excessive, and when the ratio F1 / F2 exceeds 2.5, the exposed area A1 of the warp 4 tends to be excessive.

The twist coefficient T1 calculated by the following equation (1) of the weft 5 is preferably set to 20 or more and 50 or less.
Twist coefficient T1 = (T / 10) · (D) ^1/2 ... (1)
In this formula (1), T is the number of twists of the weft 5 per 10 cm, and D is the fineness (dtex) of the weft 5.

When the twist coefficient T1 is less than 20, it is advantageous to reduce the exposed area A1 of the warp yarn 4, but it is disadvantageous to reduce the exposed area A2 of the weft yarn 5, and it is necessary to secure sufficient fatigue resistance of the weft yarn 5. Is also disadvantageous. If the twist coefficient T1 is more than 50, it is disadvantageous to reduce the exposed area A1 of the warp 4.

The twisting direction of the warp 4 and the weft 5 may be the S direction (clockwise twist) or the Z direction (counterclockwise twist), but as illustrated in FIG. 10, the warp 4 having the opposite twist direction has a belt width. It is preferable to arrange one by one in the direction or a plurality of ones such as two alternately. By weaving the warp 4 twisted in the S direction and the warp 4 twisted in the Z direction alternately in the belt width direction, when the cover rubber 6 is peeled off in the belt width direction, the warp 4 which is half of the fiber reinforcing layer 3 has the filament 4a. Even if it tends to be in an open state, the filament 4a of the other half of the warp 4 is in a state where the twist is tightened. Therefore, regardless of whether the cover rubber 6 is peeled off from one side in the belt width direction or from the other side in the belt width direction, it is easy to appropriately leave the rubber component R on the surface of the fiber reinforcing layer 3. Become. Therefore, by making the specifications in which the warp 4 twisted in the S direction and the warp 4 twisted in the Z direction are woven alternately in the belt width direction, it is possible to eliminate the directionality of the adhesiveness between the rubber and the fiber reinforcing layer 3.

Polyamide fiber has better adhesion to rubber than polyester fiber. Therefore, by adopting polyester fiber for the warp and weft 5 and polyamide fiber for the weft 5, it is possible to further improve the adhesiveness between the rubber and the fiber reinforcing layer 3 when the rubber is peeled off in the belt width direction. It will be advantageous.

When the core body 2 has a structure in which a plurality of fiber reinforcing layers are laminated, all the fiber reinforcing layers may be the fiber reinforcing layer 3 of the present invention, but in order to reduce the cost, only a part of the fiber reinforcing layer of the present invention may be used. The layer 3 can be formed, and the rest can be an inexpensive general-purpose fiber reinforced layer. In this case, the fiber reinforced layer 3 of the present invention is arranged on the outermost layer that is most susceptible to the heat of vulcanization when the conveyor belt 1 is manufactured.

That is, in the strip-shaped conveyor belt 1 before being formed in an annular shape, the fiber reinforcing layer 3 is adopted for at least the uppermost layer and the lowest layer among the fiber reinforcing layers constituting the core body 2. Of course, the specifications may be such that the fiber reinforced layer 3 is adopted only in the uppermost layer and the lowermost layer. With such specifications, the effect of the fiber reinforced layer 3 described above can be efficiently obtained while minimizing the amount of the fiber reinforced layer 3 used.

Seven types (conventional example, comparative example, and Examples 1 to 5) having the specifications shown in Table 1 were manufactured as samples of the fiber reinforced layer. In addition, a sample of the conveyor belt was manufactured using the sample of each fiber reinforcing layer. In Table 1, PET means polyester and N66 means nylon 66. Further, in Table 1, A1 means the exposed area of the warp, A2 means the exposed area of the weft, F1 means the fineness of the warp, and F2 means the fineness of the weft. The samples of each conveyor belt have the same other specifications except that the specifications of the fiber reinforcing layer that is the core body are different. Two fiber reinforced layers were embedded in each conveyor belt sample.

The following belt length change rate and strong utilization rate of warp were measured for each conveyor belt sample. In addition, the following peeling test (adhesion between the fiber reinforced layer and rubber) was performed on each sample of the fiber reinforced layer. The results are shown in Table 1.

[Belt length change rate]
A sample of each conveyor belt was stretched between pulleys under the same conditions, a running test was conducted under the same conditions, and the rate of change in the circumference of the sample before and after running was measured. The rate of change is evaluated as an index using the conventional example as 100 as a reference, and the smaller the value of the index, the better the increase in the circumference over time is suppressed.

[Strong utilization rate of warp]
For each sample of the conveyor belt before running, the strong utilization rate F of the warp calculated by the following equation (2) was grasped.
Strong utilization rate F = (strength of warp breaking in the extending direction per unit width of the fiber reinforced layer / (strength of tensile breaking of one warp x number of warps per unit width of the fiber reinforced layer)) x 100% ...・ (2)
The strong utilization rate F is an index showing how much the warp's original tensile strength can be exerted in the fiber reinforced layer, and the larger the value of F, the more efficiently the warp's strength is exerted without waste. Means to be excellent. In Table 1, the strong utilization rate of the conventional example is used as a reference 100 and evaluated as an index, and the larger the value of the index, the better.

[Peeling test]
Specimens were manufactured in accordance with JIS K 6256-1: 2013 "Peeling strength from cloth" using samples of each fiber reinforced layer. The test piece is obtained by sandwiching each sample between the adhesive rubber (NR weight ratio 50%) and the cover rubber (NBR weight ratio 20%, SBR weight ratio 40%), vulcanizing and integrating them. Then, in accordance with JIS K 6256-1: 2013 "Peeling strength with cloth", the sample and the adhesive rubber are peeled off, and the area of the adhesive rubber remaining on the joint surface of the sample with the adhesive rubber is measured. bottom. The sample was peeled off in two directions: the longitudinal direction of the belt (extending direction of the warp) and the width of the belt (extending direction of the weft). That is, the test conditions were the same for each test piece, only the fiber reinforced layer was different. The area of the remaining adhesive rubber is evaluated by an index with the conventional example as 100 as a reference, and the larger the value of the index, the larger the remaining amount of the adhesive rubber and the better.

From the results in Table 1, Examples 1 to 5 have the same performance as the conventional example in terms of the rate of change in belt length over time, fatigue resistance, and the strong utilization rate of warp threads, and the rubber and the fiber reinforced layer are attached to each other in the belt width direction. It can be seen that much more rubber remains in the fiber reinforced layer when the rubber is peeled off toward the fiber.

1 Conveyor belt 1a Longitudinal end 2 Core 3 Fiber reinforcement layer 4 Warp 4a Filament 5 Weft 5a Filament 6 Cover rubber 7 Vulcanization adhesive 8a, 8b Pulley 9 Support roller 10 Transport material R Rubber component

Claims (6)

In a method of joining a conveyor belt in which a fiber reinforcing layer for a conveyor belt having a woven structure in which warp threads extend in the longitudinal direction of the belt and weft threads extend in the width direction of the belt is embedded as a core body.
In the plan view of the fiber reinforcing layer, the ratio A1 / A2 of the exposed area A1 of the warp and the exposed area A2 of the weft is set to 3.0 or more and 5.0 or less.
At one end and the other end of the conveyor belt in the longitudinal direction, a cut is made in the cover rubber and the cover rubber is peeled off from the fiber reinforcing layer using the cut as a starting point, and the warp is formed in the extending direction of the warp. The cover rubber is peeled off from the fiber reinforcing layer in the belt width direction so that a peeling force in the orthogonal direction acts to remove the cover rubber, and the one end portion and the other end portion after the cover rubber is peeled off. A rubber component is left on the surface of the fiber reinforcing layer, and each of the fiber reinforcing layers is laminated and vulcanized with a vulcanizing adhesive interposed between the remaining rubber components. A method for joining a conveyor belt, which comprises joining the facing surfaces of the fiber reinforcing layers to each other to join the one end portion and the other end portion. The method for joining a conveyor belt according to claim 1, wherein the ratio F1 / F2 of the warp fineness F1 and the weft fineness F2 is set to 1.5 or more and 2.5 or less. The method for joining a conveyor belt according to claim 1 or 2, wherein the twist coefficient T1 calculated by the following equation (1) of the weft is set to 20 or more and 50 or less.
Twisting coefficient T1 = (T / 10) × (D) ^1/2 ... (1)
Here, T is the number of twists per 10 cm of the warp and weft, and D is the fineness (dtex) of the warp and weft. The method for joining a conveyor belt according to any one of claims 1 to 3, wherein the warp yarns twisted in the S direction and the warp yarns twisted in the Z direction are alternately arranged in the belt width direction. The method for joining a conveyor belt according to any one of claims 1 to 4, wherein the warp is made of polyester fiber and the weft is made of polyamide fiber. The method for joining a conveyor belt according to any one of claims 1 to 5, wherein the fiber reinforcing layer for a conveyor belt is embedded as at least the uppermost layer and the lowest layer of the heart body.

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