JP4362484B2 - High strength fiber composite cable - Google Patents

Description

  The present invention relates to a high strength woven union composite cable having a double twist structure.

High-strength fiber composite cable is high strength, low elongation, light weight, high corrosion resistance and high fatigue resistance, so it can replace steel wire ropes, strand cables, PC tendons, etc. As the application is expanding.
In such a high-strength fiber composite material cable, when applied to a large structure requiring high tension, a ground anchor, or the like, conventionally, as shown in FIG. A cable having a multilayer structure in which a plurality of layers are stranded and twisted, or, as shown in FIG. 1B, a plurality of strands k in which strands s composed of high-strength fibers and resin are twisted together are moderately Cables are used that are bundled in parallel while maintaining a distance.

However, such a conventional high-strength woven union composite cable has the following problems.
1. Multi-layer twisted structure cable 1) Since the strands are in a line contact relationship, the cross section is close to a circle and the surface area is small, in the terminal fixing process where resin or cement is injected into the sleeve and the sleeve and the cable are integrated during use. In order to obtain sufficient adhesion, it is necessary to separate the terminals for each strand.
2) Since the multi-layer twisted structure cable is a form in which the strands are twisted together in a predetermined direction, the equipment for twisting becomes larger as the number of strands increases, and the investment cost is enormous.

2. When using a cable 1) formed by bundling a plurality of strands in parallel, when tension is introduced into the cable, the length of each strand constituting the cable is not uniform or the cable is bent by a deflecting portion or the like. There is a possibility that the original design tension of the cable cannot be achieved because the tension is not transmitted evenly to each cable.
2) When a cable is wound around a reel to carry the cable, it loses its shape and is difficult to handle. In addition, bending stress acts due to the difference between the inner and outer diameters of the cable, which may damage the cable. .

3) Since the cable only has the strands arranged in parallel, the cable is vulnerable to twisting, and in particular, the twisted and twisted strands in the direction opposite to the strand twisting direction open and break.
4) It is weak against axial compression (bending).
5) When a cylinder is attached to the outer periphery of the cable and the cable and the cylinder are integrated by filling the inside of the cylinder with resin or cement, or when a specific gravity adjusting agent is filled into the sheath tube around the cable at the ground anchor In addition, since the filler flows out from the gap between the strands, a process for filling the gap at the time of manufacturing or construction is necessary.

  The present invention has been made in order to solve the above-described problems, and the object of the present invention is to have good and stable strength, and to have a uniform axial force against bending and a stable shape. An object of the present invention is to provide a high-strength fiber composite material cable that can be wound on a reel without losing its shape, is not easily buckled even when inserted into a hole or a cylinder, and can obtain a sufficient terminal fixing force. .

The present invention for achieving the above object, the high strength low elongation fibers multiplicity of converging the prepreg fibers impregnated with thermosetting resin and or twisted single stranded cable composite wires were stranded plurality of pieces combined A strand is formed, and a plurality of the single-stranded cables are twisted at a twist angle of 2 to 12 ° in the direction opposite to the twisted direction of the single-stranded cable.

According to the present invention, the following excellent effects can be obtained.
1) Since there is almost no unevenness in the length of each piece of twisted cable, the tension on each piece of twisted cable or each wire becomes even, and the design strength can be realized reliably.
2) Since the single twisted cable is twisted in the opposite direction to the twisted direction to make a large-diameter double twisted cable, even when the cable is bent, the axial force applied to each single twisted cable constituting the strand is equal. Moreover, since the structure is stable, it is difficult to lose its shape when it is wound on a reel or when it is unfolded, and it can be rolled up.

3) Even when a cable is inserted into a cylinder or hole, it is not easily damaged by buckling.
4) Since the surface area of the outer periphery of the cable is large, it is possible to obtain a sufficient fixing force without the need for the end portion to be ballasted as in the case of the multi-layer twisted cable when the terminal fixing process is performed.
5) Since the twisting direction of the cable is opposite to the twisting direction of the single twisted cable that is a strand, the rotation is small, the twisting is difficult, and the shape is not lost.
6) It can be easily twisted with an existing twisted wire machine, and a desired tensile tension can be obtained simply by increasing or decreasing the number of single twisted cables to be twisted together.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
2 to 6 show an embodiment of a high-strength fiber composite cable according to the present invention, wherein 1 denotes the whole high-strength fiber composite cable, and 2 denotes a high-strength low-stretch fiber and a thermosetting respectively. This is a single twisted cable composed of resin.
The high-strength fiber composite cable 1 is a single large-diameter cable obtained by twisting the single-stranded cable 2 with a plurality of strands (seven in the drawing) at a long twist pitch, that is, a twist angle α of 2 to 12 °. It is what.

  In this example, since seven single twisted cables 2 are used, one single twisted cable 2a is arranged as a core strand in the center, and six single twisted cables 2a2b are arranged as side strands around it. An intervening layer 3 is provided around the single strand cable 2a of the core strand.

  More specifically, as shown in FIG. 3, the single-stranded cable 2 (2a, 2b) as a strand is made of epoxy resin, unsaturated, high strength low elongation fiber selected from carbon fiber, aramid fiber, silicon carbide fiber, etc. It consists of a number of composite strands 20 impregnated with a thermosetting resin selected from polyester resins, polyurethane resins and the like. The composite strand 20 converges a large number of high-strength low-stretch fiber prepregs 200 or twists them with a long twist pitch, and wraps synthetic fiber yarn 202 such as high-strength low-stretch fiber or polyester fiber on the outer periphery. Covered in form.

  The twist direction of the single twist cable 2 (2a, 2b) and the twist direction of the high strength fiber composite material cable 1 are opposite to each other. That is, if the twist direction of the single twist cable 2 (2a, 2b) is, for example, the S direction, the twist direction of the high-strength fiber composite cable 1 is the Z direction. This is to reduce the rotation and make it difficult to twist and lose shape.

  The reason why the twist angle α when the single-stranded cable 2 (2a, 2b) is twisted onto the high-strength fiber composite cable 1 is limited is that the target tension is achieved without causing damage or deformation as described later. In order to achieve the strength and to enable the twisting process to be easily performed with an existing twisting machine, there is an advantage that the curing process of the thermosetting resin is not limited to the final process, as will be described later. Because. A more preferable twist angle α is 2 to 8 °.

  If the lower limit of the twist angle is 2 °, the tensile strength is high below this, but it approaches parallel, so the disadvantages of the conventional cable mentioned above, that is, when it is wound around a reel, it loses its shape and is handled. Difficult points, bending stress due to the difference between the inner and outer diameters of the cable, which may cause damage to the cable, and weakness against twisting, especially the twisting in the direction opposite to the twisting direction of the cable This is because the point that the wire opens and breaks cannot be solved.

The reason why the upper limit of the twist angle is set to 12 ° is that the tensile strength is lowered. In other words, high-strength fiber composite materials are weak against bending, shearing and twisting, and are completely brittle materials. When twisted at a large twist angle, the angle difference between the tensile direction and the fiber direction becomes large, and the strength is reduced by shearing. It is.
In a normal case, the twist pitch P when twisting the high-strength fiber composite cable 1 is made larger than the twist pitch P1 when obtaining the single twist cable 2 (2a, 2b).

The intervening layer 3 may be omitted, but is preferably present. The reason for this is that when each single twisted cable comes into contact, when the high-strength fiber composite cable is tensioned or bent, the strands are damaged by the friction and lateral pressure between each strand, Although sufficient strength cannot be exerted, the presence of the intervening layer 3 can alleviate the contact between the core strand and the side strand, and the diameter expanding action due to the presence of the intervening layer 3 also allows the contact between the side strands. This is because it is mitigated and the reduction in tensile strength (twisting loss) due to internal wear can be reduced.
Furthermore, when the high-strength fiber composite material cable 1 is put into a hole or a cylinder and a filler such as cement milk or resin is injected, the filler does not flow out from the inside of the cable (gap between strands).

  In the intervening layer 3, as shown in FIG. 6A, a linear body 30 made of synthetic resin or the like may be disposed between the outer peripheral valleys of the strand 2a. This method has an advantage that can be implemented when the single-stranded cable 2 (2a, 2b) is twisted together with a high-strength fiber composite cable. Instead of this, as shown in FIG. 6B, a resin coating 31 may be applied to the outer periphery of the single twisted cable 2a in advance by extruding molten resin or the like. The linear body 30 and the coating resin 31 are preferably thermoplastic resins such as polyethylene.

The invention is not limited to the example shown.
1) The number of the composite strand 20 which comprises the single twisted cable 2 should just be 3 or more, and is not limited to the case where it is seven like FIG. As shown in FIGS. 4B and 4C, 19 may be used.
2) The high-strength fiber composite material cable 1 is not necessarily limited to the case where the high-strength fiber composite material cable 1 has a core strand made of a single twisted cable 2a. A structure using three single-stranded cables 2 as shown in FIGS. In this example, a 3 × 7 structure and a 3 × 19 structure are adopted. In the absence of such a core strand, the intervening layer 3 is interposed between the single twisted cables 2 and 2 as representatively shown in FIG. The intervening layer 3 may be a strip formed of a resin or the like in a polygonal shape or a similar shape.
3) When the core strand 2a made of a single-stranded cable is provided, a 7 × 19 structure can also be adopted as illustrated in FIG. In this figure, the intervening layer 3 is omitted.

Next, the manufacturing process of the high strength fiber composite cable according to the present invention will be described. FIGS. 7 and 8 show two examples of the manufacturing process.
The first method is to manufacture a single twisted cable in which the resin is uncured in the layer process-lapping process-primary closing process, and to combine a plurality of uncured single twisted cables in a high-strength fiber composite in the secondary closing process. The material cable 1 is twisted, and finally the whole is cured by a curing process.
The second method is to produce a single twisted cable in which the resin is cured by the layer process-lapping process-primary closing process-curing process, and the resulting multiple twisted cables are made of high strength fibers in the secondary closing process. Twist the composite cable 1.

  In addition, there exists a 3rd system applied when there exists a core strand of a single twist cable. This is because a single twisted cable in which the resin is hardened by the layer process-lapping process-primary closing process-curing process is manufactured, and in addition, the resin is uncured in the layer process-lapping process-primary closing process. A single twisted cable is manufactured, and a resin-cured single twisted cable is used as a core strand, and a single twisted cable in which the resin is uncured is arranged as a side strand around the single twisted cable. Twist together, and finally cure the side strand made of a single twisted cable in which the resin is uncured by a curing process.

In the layer process, as shown in FIG. 8 (a), a large number of prepregs 200 impregnated with a thermosetting resin, for example, 10 to 20, are sent from the bobbin to the twister 5 and twisted at a predetermined pitch. Get 20 '.
In the wrapping step, as shown in FIG. 8B, a plurality of, for example, seven strands 20 'are fed out, and the synthetic fiber yarn 202 is fed out from the wrapping machine 6 and wound around the outer periphery of the strand 20' in a spiral shape.
In the primary closing step, as shown in FIG. 8C, for example, seven lapped strands 20 are unwound from the bobbin and twisted at a predetermined pitch, for example, 100 to 200 mm by the closing machine 7. Thus, a single twisted cable 2 ′ in which the resin is uncured is obtained.

  In the first method, if the wrapped strand 20 is twisted at a predetermined pitch, for example, 100 to 200 mm, with the closing machine 7 to obtain an uncured single twisted cable 2 ′, the state shown in FIG. ) With a closing machine 9 in the range of 2 to 12 °, twisted with the twisting direction reversed to the twisting direction in the single twisted cable twisting process, and the resin uncured raw high strength fiber composite material A cable 1 'is obtained, and it is passed through a tunnel-shaped heat treatment furnace 8 and heated at 120 to 135 [deg.] C. to cure the resin, thereby obtaining the high-strength fiber composite cable 1 of the present invention.

  In the second method, a piece of uncured piece twisted cable 2 ′ that is cured at a temperature of 120 to 135 ° C. through a tunnel-shaped heat treatment furnace 8 as shown in FIG. A twisted cable 2 is obtained. And these resin hardening piece twisted cables 2 are twisted together by the closing machine 9, and this invention high strength fiber composite material cable 1 is obtained. At this time, the twist angle is set in the range of 2 to 12 °, and the twist direction is reversed to the twist direction in the single twist cable twisting step. In the first and second methods, the curing process is simple, so the process is simple.

In addition, when providing the intervening layer 3, in the cable structure without the core strand, the secondary closing process may be performed by arranging the strands and the filaments to be the intervening layer in the center and arranging the strands around them. .
Further, in the case of a high-strength fiber composite cable structure having a core strand, an intervening layer is applied to the outer periphery of the strand made of one piece of twisted cable, and the strand 2b made of another piece of twisted cable is formed around that. And the secondary closing process may be performed. The single twisted cable may be cured or uncured.
In the third method, when the side strand 2b made of an uncured single twisted cable is twisted, the strand 2a made of a rigid single twisted cable in which resin is cured is present at the center, so that the twisting process is easy. There is an advantage of being.

As a specific example, the high strength fiber composite material cable of the present invention was manufactured using the second method as a manufacturing method.
15 prepregs made by bundling 12,000 fibers with a diameter of 7 microns with carbon fiber impregnated with epoxy resin are twisted in a twisting direction Z and a pitch of 90 mm, and then lapped to obtain a strand having an outer diameter of 4.2 mm. It was.
Seven strands of this strand were twisted in a twisting direction S and a pitch of 160 mm to obtain a single twisted cable having a 1 × 7 structure. The single stranded cable was heated in a heat treatment furnace at 130 ° C. for 90 minutes to cure the resin.

Of the seven stranded cables, one outer periphery is coated with polyethylene to form a core strand, and six uncoated ones are side strands, and the twist direction Z and the twist angle α are 2 to 18 °. The range was twisted to obtain a double twisted cable of the present invention having a 7 × 7 structure. Incidentally, the twist pitch α: 2 ° has a twist pitch of 2200 mm, the twist angle α: 4.1 ° has a twist pitch of 1100 mm, and the twist angle α: 5 ° has a twist pitch of 900 mm.

  FIG. 9 shows the results of a nine-level tensile test performed on the obtained double-stranded cable. From this result, it can be seen that when the twist angle is in the range of 2 to 12 °, particularly 2 to 8 °, almost no decrease in the breaking load is observed.

For comparison, a twisted angle α = 4 °, a double-stranded cable having the 7 × 7 structure was manufactured at α = 4 ° without coating a core strand made of a single-stranded cable, and a tensile test was performed. As a result, the breaking load was 1100 kN, the twist angle α = 4 °, and the double-stranded cable in which the core strand was coated was 1250 kN.
Further, the breaking load of the conventional cable (referred to as Conventional Example 2) in which the seven strands were bundled in parallel was also compared. As a result, the conventional example 2 was 1070 kN, which was inferior to the present invention.

  Regarding the high-strength fiber composite cable, the relationship between the reel diameter and the twist length was investigated by a winding experiment. As a result, when the twist angle α is in the range of 2 to 18 °, if the twist length P / reel barrel diameter D is 0.73 or less, it can be normally wound as shown in FIG. It was confirmed that there was. When the twist angle α was 1.6 °, that is, the twist pitch was 2800 mm, the cable was damaged or deformed during winding when the P / D was 0.93. For comparison, a winding test was also performed on the conventional example 2, but as a result, the shape was deformed as shown in FIG.

For the cable of the present invention (7 × 7 structure) having a twist angle α of 4 °, a core strand made of a single-stranded cable and having a twist angle α of 4 °, a bending angle of 2θ with a bending diameter of 200 mm as shown in FIG. The bending tensile test was performed in the range of 0 ° to 8 °.
For comparison, a similar bending tensile test was performed on a 1 × 37 structure (conventional example 1) having the same cross-sectional area and a cable in which seven strands were bundled (conventional example 2). The result is shown in FIG. As can be seen from this figure, the cable of the present invention exhibited good bending performance, whereas the conventional example 2 had the greatest decrease in breaking load due to bending.

As shown in FIG. 12, a cylindrical body is covered with a 7 × 7 cable outer periphery in which a core strand made of a single twisted cable is covered with polyethylene, and the cylinder is packed with epoxy clay at both ends of the cylindrical body and sealed. When cement milk was injected from the injection hole provided in the lower part of the body, the filling was successful without the cement flowing out of the cable. From this result, it can be seen that the intervening layer is effective.
Further, in order to examine the fixability, the high-strength fiber composite material cable 1 of the present invention was inserted into a steel pipe sleeve 15 as shown in FIG. For comparison, as shown in FIG. 14, the wire of Conventional Example 1 was separated and inserted into the sleeve, and cement milk was injected. As a result, the high-strength fiber composite material cable 1 of the present invention obtained high fixing strength even though each strand made of a single-stranded cable was not separated. This is because, in the high-strength fiber composite cable of the present invention, the single-stranded cables that are strands are in point contact with each other, so that the irregularities on the outer periphery of the cable are large, the adhesion surface area is large, and the spiral of the single-stranded cable becomes the pulling resistance It is because of that.

(A) And (b) is a partial perspective view of the conventional high-strength fiber composite cable, respectively. It is a fragmentary perspective view which shows an example of the high strength fiber composite material cable by this invention. It is a fragmentary perspective view which shows the composite strand in this invention. (A) (b) (c) is sectional drawing which shows the other example of this invention cable. (A) is explanatory drawing which shows the twist angle of this invention cable, (b) is explanatory drawing which shows twist length. (A) (b) is the side view which illustrated the intervening layer of this invention cable. (A) (b) is explanatory drawing which shows the example of a manufacturing process of this invention cable. (A) is an explanatory view of a layer process, (b) is an explanatory view of a lapping process, (c) is an explanatory view of a primary closing process, (d) is an explanatory view of a secondary closing process, and (e) is a curing process. It is explanatory drawing of. It is a diagram which shows the relationship between a twist angle and a breaking load. (A) is a top view which shows the winding test state of this invention cable, (b) is a top view which shows the winding test state of the conventional cable. (A) is explanatory drawing which shows the outline | summary of a bending tension test, (b) is a diagram which shows the bending angle and breaking load of this invention cable and a conventional cable. It is a perspective view which shows a filling test state. (A) is a longitudinal side view showing a state of terminal fixing processing of the cable of the present invention, and (b) is a cross-sectional view. (A) is a vertical side view showing the terminal fixing processing state of a conventional multilayer twisted cable, and (b) is a cross-sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High-strength fiber composite material cable of the present invention 2 Single-stranded cable 2a Core strand 2b Side strand 20 Composite strand

Claims (1)

A single twisted cable (2) in which a plurality of composite strands (20) obtained by converging or twisting a large number of prepregs impregnated with a thermosetting resin into a high-strength low-stretch fiber is used as a strand. A high-strength fiber composite cable comprising a plurality of cables (2) twisted at a twist angle of 2 to 12 ° and twisted in the opposite direction to the twist direction of the single-twist cable (2).

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