JPH05338752A - Conveyor belt - Google Patents

Abstract

PURPOSE:To make each of the element wire cause to produce a gap between the element wires and thereby improve permeability of a rubber and the like into the interior of a steel cord by setting the twisted length of internal three- layer element wires, which are twisted together in a parallel twist, to a specific ratio against the twisted length of the outermost element wire. CONSTITUTION:A steel cord 3 has three center element wires 3a making mutual close contact, three No.1 side element wires 3b arranged in positions opposite to the mutual contact portions of element wires around said element wire 3a and three No.2 side element wires 3c whose diameter is smaller than that of the element wires 3b and which are arranged between mutual element wires 3b. The element wires 3b and 3c have 9 to 15 No.3 side element wires 3d around them. Respective element wires 3a, 3b, 3c making mutual line contact are twisted in parallel and the twisted length of element wires 3a, 3b, 3c are 0.6 to 9 times the length of element wires 3d. Thus the element wires 3d make point contacts with element wires 3b, 3c in the inner side thereof thereby causing to make gaps between the element wires and improve permeability of the rubber and the like at the time of forming a conveyor belt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conveyor belt, and more particularly, to a steel cord that is damaged when it is damaged by improving permeability of rubber or the like into the steel cord to reduce air permeation in the steel cord. The present invention relates to a conveyor belt that has improved corrosion resistance and improved life.

[0002]

2. Description of the Related Art Generally, a conveyor belt used for transporting relatively light items such as foods has a belt strength ST.
-500 to ST-2000 conveyor belts are used, and multiple steel cords are embedded in parallel along the longitudinal direction to reinforce the belt in a belt-shaped belt made of rubber, plastic, etc. Is configured.

By the way, the strength of the belt used conventionally
Examples of spiral type steel cords used in ST-500 to ST-2000 conveyor belts include:
Three first side strands having the same diameter are arranged around the three center strands having the same diameter, which are adjacent to each other, at positions facing the contact portions of the center strands, and these three side strands. A first side wire and a second side wire, which are arranged between the first side wires and have three second side wires having a diameter smaller than that of the first side wires. Around the wire, twelve third side wires having the same diameter are arranged.

In this steel cord, a first side element wire, a second side element wire and a third side element wire are arranged around three central element wires, and at the same time, they have the same twist length and the same length. They are twisted in the twisting direction, and this cord structure is usually 3+ (3
+3) +12, which is expressed as 1 × W (21) in a broad sense from the manufacturing method. Note that W is a Warrington type, and all the strands of this steel cord are twisted in parallel.

[0005]

However, the conveyor belt having the above-mentioned spiral type steel cord is excellent in rupture resistance, but the strand of the third side strand constituting the steel cord. Have the same diameter,
Further, the first side strand, the second side strand, and the third side strand are twisted in the same twist length, in the same twist direction, and in parallel twist, and each strand is in line contact, so the third side The permeability of rubber etc. to the inside is poorer than that of the strands, leaving voids inside the steel cord, which results in higher air permeability inside the steel cord, and when the conveyor belt is damaged, moisture inside the steel cord However, there is a problem that the steel cord is corroded, the strength of the belt and the adhesiveness with the belt are reduced, and the life of the conveyor belt is significantly reduced.

The present invention has been devised in view of such conventional problems. It improves permeability of rubber or the like into the inside of the steel cord to reduce air permeation in the steel cord. It is an object of the present invention to provide a conveyor belt that is excellent in breaking resistance as well as preventing corrosion of steel cords that occur to improve the service life.

[0007]

In order to achieve the above object, the present invention provides a steel cord around three central wire rods having the same diameter, which are adjacent to each other, and which faces the contact portions of the central wire rods. Positioned three first-side strands of the same diameter, and three same-diameter strands that are arranged between the three first-side strands and have a smaller diameter than the first-side strands. And a second side wire of 9 to 1 around the first and second side wires.
The central strand, the first side strand, and the second side strand of a conveyor belt including five third side strands having the same diameter are formed in the same twisting direction, and the central strand is formed. Wire, first side wire,
Also, the gist is that the twist length of the second side wire is set to 0.6 to 0.9 times the twist length of the third side wire.

[0008]

The present invention is configured as described above and includes the central wire,
The first side strand and the second side strand are formed in the same twisting direction, and the twist lengths of the central strand, the first side strand, and the second side strand are set to the third side strand. Since the twist length is set to 0.6 to 0.9 times, the structure has a parallel twist portion and a cross twist portion, and the third side wire and the first side wire inside the third side wire, and the The two side strands are in point contact with each other to form a gap between the strands, which can improve the permeability of rubber and the like during molding of the conveyor belt.

Further, since the permeability of rubber or the like into the steel cord is good, the voids remaining inside the steel cord are reduced and the air permeability is lowered, so that even if the conveyor belt is damaged, moisture will be lost. Does not easily penetrate into the steel cord, prevents the steel cord from being corroded, and suppresses the reduction of the belt strength and the adhesive force with the belt, and the life of the conveyor belt can be kept long.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a partially cutaway perspective view of a conveyor belt according to the present invention. The conveyor belt 1 is for reinforcing a belt body 2 made of rubber or plastic and the like as in the conventional case. And a plurality of spiral type steel cords 3 which are embedded in parallel along the longitudinal direction thereof.

This steel cord 3 has a structure shown in FIGS. 2 (a), 2 (b),
As shown in (c), three adjacent center strands 3a of the same diameter are arranged, and the three center strands 3a are arranged around the three center strands 3a at positions facing the contact portions of the center strands 3a. The three first side strands 3b having the same diameter and the three first side strands 3b arranged between each other and having a smaller diameter than the first side strands 3b. And the second side wire 3c having the same diameter.

Around the first side wire 3b and the second side wire 3c, there are 9 to 15 third wires having the same diameter.
The side wire 3d is provided. This third side wire 3d is 9 to 1
The number of five wires means that if the number of wires is less than 9, the wire diameter of the third side wire 3d becomes thicker, so that the bending stress generated increases and the durability against bending fatigue decreases. This is because if the number of wires exceeds 15, the wire diameter of the third side wire 3d becomes thin, and the cross-sectional area reduction rate due to internal wear increases and the durability decreases.

Further, in the steel cord 3, the central strand 3a, the first side strand 3b, and the second side strand 3c are arranged in the same twisting direction, and the third side strand 3d is at the center. The strand length is larger than the strand length with the strand 3a, the first side strand 3b, and the second side strand 3c. That is, the central strand 3a, the first side strand 3b, and the second strand
The side strands 3c are in line contact with each other and twisted in parallel,
The 3rd side strand 3d is this center strand 3a twisted in parallel,
The first side wires 3b and the second side wires 3c are twisted in the same twisting direction while intersecting with each other and the third side wires 3d have a small gap therebetween.

Further, the twist lengths of the center strand 3a, the first side strand 3b, and the second side strand 3c are 0.6 to 0.about the twist length of the third side strand 3d. 9 times, that is, the central strand 3a, the first side strand 3b, and the second side strand 3c which are twisted in parallel with each other, and the central strand 3a, the first side strand 3b,
Further, the twist length ratio with the third side element wire 3d which is twisted while intersecting with the second side element wire 3c is 0.6 to 0.9.

When the twist length ratio is less than 0.6, the air permeation amount of the steel cord 3 is very low and good, but the cutting load of the steel cord 3 is low and the breaking resistance is lowered (much worse). On the other hand, if the twist length ratio exceeds 0.9, the amount of air permeation through the steel cord 3 cannot be sufficiently suppressed. In this way, the central wire 3a, the first
The side strands 3b and the second side strands 3c are formed in the same twisting direction, and the twist lengths of the central strand 3a, the first side strand 3b, and the second side strand 3c are the same as those of the first strand. Since the twist length of the 3-side strand 3d is set to 0.6 to 0.9 times, the structure has a parallel twist portion and a cross twist portion, and the third-side strand 3d and the first inside wire 3d are formed. The side strands 3b and the second side strands 3c are in point contact with each other to form a gap between the strands, thereby making it possible to improve the permeability of rubber or the like into the steel cord 3 when the conveyor belt 1 is molded. I can.

Further, the voids remaining inside the steel cord 3 are reduced and the air permeability is lowered, so that even if the conveyor belt 1 is damaged, it is difficult for water to enter the steel cord 3 and the steel cord 3 It is possible to prevent the corrosion of No. 3 and to suppress the strength of the belt and the decrease of the adhesive strength with the belt body 2, and to maintain the life of the conveyor belt 1 for a long time.

Since the steel cord 3 is twisted in two steps by changing the twist length of the third side wire 3d, the name is 1 ×.
CW (21), 1 × CW (18), 1 × CW (24),
That is, it is written as covered warrington. Next, as shown in FIG. 2, each steel cord (1 × CW (21), 1
XCW (18), 1xCW (24)) was used as a reinforcing material, and a conveyor belt having the specifications shown in Table 1 below was prototyped. Under the conditions shown below, an air permeation test of steel cord in the belt and internal wear were performed. A test, an internal corrosion test, and a belt durability test were performed.

[0018] 1. Air Permeation Rate Test The produced conveyor belt was cut into a length of 500 mm in the longitudinal direction, and as shown in FIG. 3, 0.5 kgf / cm ² of air was passed from one end of the steel cord cross section in the conveyor belt,
The amount of air coming out from the other end was measured and shown as the amount of air permeation per minute. 2. Internal Wear Test As shown in FIG. 4, one steel cord taken out from the produced conveyor belt is bent into a semi-arcuate shape, and one end is rotated by a motor M in the bent state. Each rotation, the relative position of each wire constituting the steel cord changes, and wear occurs between the wires. (1). Test time (cord rotation speed) 90 million times (2). Measurement items a) Cutting load of steel cord b) Reduction rate of cross-sectional area of the third side wire (3). The radius of bending the steel cord is 700 times or more of the representative wire diameter in order to eliminate the influence of bending stress. Seven hundred nineteen seventy two 3. Internal Corrosion Test As shown in FIG. 5, the center of one steel cord taken out from the produced conveyor belt is scratched with a scalpel from the surface of the steel cord to the inside of the steel cord. This steel cord is bent into a semi-circular shape, and one end of the steel cord is rotated by a motor M while being immersed in salt water having a concentration of 10%. If there are voids inside the steel cord, salt water will penetrate into the steel cord from the wound part that was put in with a scalpel, and each wire of the steel cord will be corroded by the salt water. Disassemble the steel cord after the corrosion test and observe the degree of corrosion of the steel cord of the damaged part to judge. (1). Judgment standard No corrosion 0 Very slight corrosion 1 Moderate corrosion (only one side) 2 Significant corrosion (both sides) 3 (Rubber adhesion decreases and practically unusable level) Very corrosion (entire surface) 4 (Rubber adhesion) (2). Test time 1 million times (steel cord rotation speed) (3). The radius of bending the steel cord is 700 times or more of the representative wire diameter in order to eliminate the influence of bending stress. 4. Belt durability test Use two pulleys with a pulley diameter of 500 mm.
The prepared conveyor belt was attached to each pulley (safety factor: 7.0), and the cutting load (kgf / piece) of the steel cord after the number of times of passing through the pulley was 5 million was measured. 1 x CW
(21) 1 × CW (18), 1 × CW (24) The test results of Examples performed by changing the twist length for each steel cord are shown in the following table including the conventional example and the comparative example. 2, shown in Table 3 and Table 4. As a reference, the twist reduction rate (%) of the used steel cord and the raw cord cutting load (kgf / piece) before use produced are also shown.

[0019]

[0020]

[0021] As is clear from Table 2, in the case of a steel cord having a 1 × CW (21) structure, the air permeation rate of the steel cord is as small as 20 cc / min or less when the twist length ratio is 0.6 to 0.9 times. The rubber penetration was good, and the internal corrosion degree of the steel cord was also good. Further, the reduction rate of the cross section of the strand due to the internal wear of the steel cord is as small as 10% or less, and the breaking force of the steel cord can be kept as high as the index value of 95 or more, and a conveyor belt having a long life and excellent durability is obtained. I know that I can do it.

In the comparative example in which the twist length ratio was 0.5 times, the amount of air permeation through the steel cord was small and the rubber permeability was good, but the cross section of the strand was reduced due to internal wear of the steel cord. The rate was as large as 30%, and the breaking strength of the steel cord was 90 as an index value, which was greatly reduced, and was not at a level capable of enduring practically long life. On the other hand, in the case of the conventional example of 1 × W (21) in which the twist length ratio is 1.0, the air permeation rate of the steel cord is 85 cc / min.
It was large, the rubber permeability was poor, and the internal corrosion degree of the steel cord was also poor, so it was not at a level that could practically endure a long life.

Further, the steel cord structure is changed to 1 × C.
Even in the case of W (18) and 1 × CW (24), Table 3
Also, as is clear from Table 4, in the examples of the present invention, the air permeation amount of the steel cord was small, the rubber permeability was good, and the internal corrosion degree of the steel cord was also good, as described above. Furthermore, it can be seen that the reduction rate of the cross section of the strand due to internal wear of the steel cord is small, the breaking force of the steel cord can be kept high, and a conveyor belt having a long life and excellent durability can be obtained.

[0024]

As described above, the present invention is configured as described above, in which the central strand, the first side strand, and the second side strand are formed in the same twisting direction, and the central strand, the first side The twist length of the strand and the second side strand is 0.6 to 0.9 of the twist length of the third side strand.
Since it is doubled, the structure has a part in which the strands are twisted in parallel and in contact with each other and a part in which the strands are cross-twisted and in point contact with each other. The third side strand and the first side strand inside the third strand, and Second
A gap is formed between the side wires and the side wires, which has the effect of improving the permeability of rubber and the like when forming the conveyor belt.

Further, since the permeability of rubber or the like into the steel cord is good, the voids remaining inside the steel cord are reduced and the air permeability is lowered, so that even if the conveyor belt is damaged, moisture will be lost. Does not easily penetrate into the steel cord, prevents corrosion of the steel cord, suppresses the reduction of the belt strength and the adhesive strength with the belt body, and has the effect of keeping the life of the conveyor belt long. In addition, as long as the twist length ratio of the third side wire to the first side wire inside the third side wire and the second side wire is maintained at 0.6 to 0.9 times, the conventional Warrington type steel cord is used. It has the effect of maintaining a close breaking resistance.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a conveyor belt according to the present invention.

2A, 2B, and 2C have a code structure of 1 × CW (21), 1 × CW (18), and 1 × CW, respectively.
It is sectional drawing of the steel cord of (24).

FIG. 3 is an explanatory diagram illustrating an air permeation amount test of a steel cord.

FIG. 4 is an explanatory diagram illustrating an internal wear test of a steel cord.

FIG. 5 is an explanatory diagram illustrating an internal corrosion test of a steel cord.

[Explanation of symbols]

 1 Conveyor Belt 2 Belt Main Body 3 Steel Cord 3a Center Wire 3b First Side Wire 3c Second Side Wire 3d Third Side Wire

Claims (1)

[Claims] 1. A belt-shaped belt main body, and a plurality of steel cords embedded in the belt main body in parallel along the longitudinal direction, wherein the steel cords are three central elements having the same diameter and adjacent to each other. Around the wire, three first wires of the same diameter are arranged at positions facing the contact portions of the central strands.
Disposed between the side strands and the three first side strands,
In addition to having three second side wires of the same diameter that are smaller in diameter than the first side wires, 9 to 15 third sides of the same diameter are provided around the first and second side wires. A conveyor belt comprising strands, wherein the central strand, the first side strand, and the second strand
Side strands and the same twist direction, and the central strand,
A conveyor belt, wherein the twist length of the first side strand and the second side strand is set to 0.6 to 0.9 times the twist length of the third side strand.