JPH0339517Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a steel cord for reinforcing a belt.

[Conventional technology and its problems]

Wallington-type steel cords are used as reinforcing materials for conveyor belts that are wound around pulleys and receive loads on the tension side.

This Wallington type steel cord is generally constructed by twisting six side strands B' around the outer periphery of a core strand A', as shown in Fig. 3.
Six wires 2 were arranged around the outer periphery of the lateral wire as the first side wire, and six small diameter wires 3 and the same number of large diameter wires 3' were arranged around the outer periphery of the lateral wire 2 as the second lateral wire. .

This structure has the smallest difference between the maximum strand diameter and the minimum strand diameter among 19-wire parallel stranded cords, and has excellent flexibility. The bending stress tends to cause the core wire and strand of the core strand to move in the longitudinal direction, causing a portion of the cord to eventually pop out from the end of the cord and further protrude to the outside of the belt.

This is thought to be because the wires constituting the first side wire and the second side wire around the core wire 1 are in contact with each other and twisted, so the tightening force against the core wire 1 is not sufficient, and this can be improved. As a method, increasing the diameter of the core wire 1,
It is conceivable to twist the first side wire and the second side wire in the same side wire group in a non-contact manner.

According to this, it is possible to prevent the core wire from popping out. However, in this structure, on the other hand, the bending fatigue resistance decreases due to the increase in the diameter of the core wire, and a new problem of breakage of the core wire due to bending stress arises, making it impractical.

[Means for solving problems]

The present invention was devised through research to solve the above-mentioned conventional problems.The purpose of this invention is to have a simple structure that prevents the core wire from protruding or breaking, and to reduce the bending radius of the belt. To provide a steel cord for reinforcing a belt, which can exhibit a good reinforcing effect over a long period of time even if it is made small.

In order to achieve this objective, the present inventors conducted repeated experiments and twisted the core strands without using the core wire, which was considered indispensable in Warrington-type steel cords, and twisted the core strands together with the side strands with the core wire on the outer periphery. I tried combining and twisting.

As a result, the strength of the core strand alone against cutting load was inferior to that of a strand with a core strand. However, it was found that when side strands with core wires were placed around the outer periphery, there was almost no difference in strength; in fact, stress self-absorption occurred during repeated bending due to the hollow center of the core strand. did.

Based on this knowledge, the present invention changed the concept of the conventional Warrington type steel cord and made the core strand a hollow core structure.

In other words, the feature of the present invention is that multiple side strands are twisted around the outer periphery of the core strand,
In a Warrington-type steel cord in which the core strand and the side strands have a first side wire group consisting of wires of the same diameter and a second side wire group consisting of alternating small diameter wires and large diameter wires, the center portion of the core strand is longitudinally The reason is that the gap runs in the direction.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Figure 1 shows an example of the steel cord for reinforcing belts according to the present invention.
It is configured as W(18)+6×W(19).

That is, A is a core strand, and B is a side strand consisting of six strands twisted around the outer periphery of the core strand.

The core strand A has a gap c running in the longitudinal direction at the center, six wires d1 are arranged around the outer periphery of the center gap c, and a second side line group is placed outside these six wires d1. As, small diameter wire d2
It is constructed by alternately arranging six large diameter wires d3 and twisting them together.

On the other hand, side strand B consisting of six strands is
In each case, a core wire d4 is arranged at the center, six wires d5 are arranged as a first side wire on the outer periphery, and six small diameter wires d6 and six thick wires d7 are arranged on the outer periphery as a second side wire. They are arranged alternately and twisted.

Specific examples are as follows.

Core strand A Wire d1 0.43mmμ×6 Wire d2 0.265mmμ×6 (second side wire) Wire d3 0.390mmμ×6 (same) Side strand B Core wire d4 0.370mmμ Wire d5 0.350mmμ×6 (first side wire) Wire d6 0.290mmμ×6 (second side wire) Wire d7 0.380mmμ×6 (same) Since the present invention has the above-mentioned configuration, if it is embedded in a conveyor belt, repeated bending stress will not be applied to the steel cord. However, since the center of the core strand A is the void c,
Phenomena such as longitudinal movement of the core wire, protrusion of the core wire from the end of the cord, or protrusion of the core wire to the outside from the belt do not occur as in the prior art. In addition, there is no reduction in bending fatigue resistance, which would occur when the diameter of the core wire is increased, and a disconnection accident of the core wire due to this does not occur.

Rather, by forming the center of the core strand A into a void structure, the core strand A becomes a cushion chamber that absorbs various stresses acting on the core strand during belt operation, thereby improving the properties required of the belt, such as flexibility. Furthermore, the amount of materials required for manufacturing the steel cord can also be reduced.

[Effect of idea]

According to the present invention described above, a plurality of side strands are twisted around the outer periphery of the core strand, and the core strand and the side strands alternately consist of a first side wire group consisting of wires of the same diameter, small diameter wires, and large diameter wires. In the Warrington type steel cord, which has a second side wire group arranged in
Although it has a simple structure, the core wire does not protrude or break, and even if the bending radius of the belt is made small, it has the practical effect of being able to exhibit a good reinforcing effect over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a steel cord for reinforcing a belt according to the present invention, and FIG. 2 is a sectional view showing the structure of a conventional Warrington-type steel cord for reinforcing a belt. A...heart strand, B...side strand, c
...Void area.

Claims (1)

[Scope of utility model registration request] A plurality of side strands are twisted around the outer periphery of the core strand, and the core strand and the side strands are a first side wire group consisting of wires of the same diameter and a second side wire group consisting of alternating small diameter wires and large diameter wires. A steel cord for reinforcing a belt, characterized in that the core strand A has a void C running in the longitudinal direction in the center of the Warrington type steel cord.