JP2004131969A - Anchorage structure and anchorage forming method of wire rod end, and mounting structure of anchored wire rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a anchorage structure and an anchoring formation method of a wire rod end by which an anchorage efficiency the same as the conventional cases or higher than that can be obtained and which is constituted in lightweight and compact manner. <P>SOLUTION: In the anchorage structure of a wire rod end, high strength steel sleeves 2 are shrunk in diameter and press-fitted at the wire rod end and the outer diameter D of the high strength sleeve 2 after press-fit is anchored in 1.8 times or smaller the outer diameter d of the wire rod end 4. The structure has a filler in between the outer peripheral face of the wire rod ends and the inner peripheral face of the high strength sleeve 2. The high strength sleeve 2 is made of a steel material with 800 MPa or higher tensile strength. The sectional outer shape of the high strength sleeve 2 is polygonal. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fixing structure and a fixing forming method of a wire end portion, and a fixing structure of a fixed wire, and in particular, a metal wire such as a steel wire or a steel stranded wire, or a high-quality material such as carbon fiber, aramid fiber, or glass fiber. The present invention relates to a fixing technique for an end portion of a wire rod such as a composite cable using a low-strength fiber.
[0002]
[Prior art]
Conventionally, cables used for prestressed concrete structures and the like, and cables used for bridge structures such as suspension bridges and cable-stayed bridges include PC steel materials such as PC steel strands and PC steel wires, or, in recent years, high strength and low elongation. Wires such as composite cables using fibers are used. When these wires are attached to a structure, a metal sleeve serving as a crimp grip is attached to the end of the wires by crimping, and one or more of them are attached to a fixing plate. As a technique for attaching a metal sleeve by crimping to an end of a wire rod, Patent Literature 1 (JP-B-58-53225), Patent Literature 2 (JP-A-8-82043), Patent Literature 2 3 (Japanese Patent Application Laid-Open No. 2000-345656), and Patent Document 4 (Japanese Patent No. 3123644) is a proposal of a technique for attaching it to a structure.
[0003]
Patent Document 1 discloses that a sleeve having a substantially tapered outer peripheral portion in which one side serving as a die inlet has a large diameter and the other side has a small diameter is fitted to a PC steel wire such that the small diameter side is a steel wire end side, and is extruded. A crimping joining method of a sleeve and a steel wire has been proposed, in which the outer peripheral portion of the sleeve is deformed by pressing with a die by processing, and the sleeve is plastically deformed from a large diameter side and integrally joined to the steel wire. .
[0004]
According to the above-described invention, the following operation and effect are provided. That is, since the sleeve having the tapered outer peripheral portion is fitted and crimped so that the small-diameter side is the steel wire end side, the sleeve can be crimped by extrusion using a fixed die, and the roller die can be used. An extremely strong crimping force can be maintained as compared with the case of crimping by rolling. Moreover, the large-diameter side of the sleeve undergoes strong working deformation during crimping to the steel wire to produce a working effect, and that portion becomes a bearing surface that receives a strong compressive load when tension is introduced into the PC steel wire. The strength of the sleeve against the compressive load is significantly improved as compared with the conventional sleeve, and the sleeve is not deformed even when a large compressive load is applied due to the tension, so that the fixing efficiency can be further increased. Since processing is performed from the large diameter side by compression processing, the processing degree becomes large on one side which is the die entrance of the sleeve, but since the processing degree gradually decreases, troubles such as clogging of the die and generation of burrs also occur Absent. In addition, the length of the sleeve after the crimping process can be reduced by about 20% or more than that of the conventional method, and it can be used in places where the sleeve length cannot be used or where the fog of the concrete member has to be increased. .
[0005]
Patent Document 2 discloses that a sleeve made of chromium molybdenum steel or nickel chromium molybdenum steel is formed with irregularities on an inner peripheral surface of the sleeve, and a carburized layer is formed only on an inner peripheral portion including the irregularities. In addition, a compression grip for fixing a PC steel wire having a hardness of the inner peripheral portion of Hv700 or more has been proposed. According to this compression grip, it can be composed of only the sleeve, and can obtain a high degree of crimping and fixing load equal to or higher than that of the insert method, and the fixing process can be easily performed by die extrusion, and the production can be simplified. It is said that cost can be reduced.
[0006]
Patent Literature 3 proposes a PC steel crimping grip in which a PC steel is fitted into an insertion hole of a sleeve via an insert. In this crimping grip, the sleeve is drawn and crimped to a PC steel wire with a cold drawing die, and a plurality of inserts, which are wedge pieces, are inserted into the insertion holes of the sleeve, and a sawtooth cross section formed on the inner and outer surfaces thereof. The ridge of the hole cuts into the outer peripheral surface of the PC steel wire and the inner surface of the insertion hole so that the PC steel wire does not come out of the sleeve. Because of the contact, the stress is not concentrated on the PC steel material on the inlet side of the insertion hole, and the effect is that the tensile fatigue strength is increased.
[0007]
Patent Document 4 discloses a fixing structure of a bridge cable in which a crimping grip is fixed to an end of a PC steel stranded wire and a side end of the crimping grip is engaged with a fixing plate inside the anchor socket. It is divided into a fixing part and a socket part, and in the fixing part, an insertion hole of approximately the same diameter into which a PC steel strand is inserted is opened on one side, and a crimping grip is provided on the other side on the axis of the insertion hole. The fixing plate is connected to the fixing plate with a screwing structure, and the socket is connected to the fixing part with a screw structure. A combined anchoring structure for bridge cables has been proposed.
[0008]
According to this invention, the peripheral edge of the side of the fixing plate where the insertion hole is opened is supported by the anchor socket, and when a tensile load acts on the cable, the center of the thickness of the fixing plate (neutral axis) is used as a boundary. The insertion hole side is on the tension side, and the side surface on which the opposite crimp grip engagement hole is opened is on the compression side. Then, the crimping grip inserted into the crimping grip engaging hole formed on the compression side is pressed by the peripheral wall surface of the crimping grip engaging hole, and the crimping grip expands (expands) as it tries to slip out of the PC steel wire. ). Thereby, the pressure grip is integrated with the fixing plate. Therefore, the crimping grip mounted and mounted on the compression side of the fixing plate can be considered as an effective cross-sectional area, thereby making it possible to minimize the amount of cross-sectional loss due to the opening of the crimping grip engaging hole. The thickness of the plate can be reduced as compared with the conventional structure. Furthermore, the above configuration allows the pressure grip to be integrated with the fixing plate, and the insertion holes are opened in parallel with the center of the fixing plate, so that the diameter of the fixing plate can be reduced as compared with the conventional structure. It becomes possible. It has been.
[0009]
[Patent Document 1]
JP-B-58-53225 (claims, page 2, column 4, lines 30 to 34, amended gazette under the provisions of Article 64 of the Patent Law dated June 26, 1992)
[Patent Document 2]
JP-A-8-82043 (Claims, paragraph [0023])
[Patent Document 3]
JP-A-2000-345656 (claims, paragraph [0024])
[Patent Document 4]
Japanese Patent No. 3123644 (Claims, paragraphs [0007] and [0008])
[0010]
[Problems to be solved by the invention]
Although the above effect is expected in the sleeve after the crimping process performed by the crimping joining method described in Patent Document 1, the material of the sleeve is mild steel, and as is clear from the examples, the sleeve and the 19 sleeves are used. Compression bonding with a 17.8 mm diameter PC steel wire is performed by an extrusion method using a 35 mm diameter die (Patent Document 1, page 2, column 4, lines 6 to 9), and the outer diameter of the PC steel wire is used. As compared with (d = 17.8 mm), the outer diameter (D) of the extruded sleeve is D = 35 mm, which is the same as that of the conventional sleeve. Not suitable for
[0011]
In the compression grip for fixing a PC steel wire described in Patent Literature 2, the above-described effects are expected, and the use of a chromium molybdenum steel material or a nickel chromium molybdenum steel material as a sleeve has high material strength and is desired in recent years. Although it is expected that the fixing portion can be made more compact as described above, as apparent from Table 3 of paragraph [0019], the outer diameter D of the sleeve after pressure bonding with respect to the wire diameter d from the PC is determined by the ratio (D / d). As is clear, the ratio (D / d) of Patent Document 1 is almost the same at about 2.0, and the diameter is hardly reduced. In addition, since the inner peripheral surface of the sleeve is subjected to unevenness processing, stress concentration is a concern, and there is a limit in reducing the thickness of the sleeve, and it is difficult to make the outer diameter of the sleeve thinner. Further, a carburized layer is formed only on the inner peripheral surface, which increases the number of manufacturing steps and raises the cost.
[0012]
Although the above-mentioned effects are expected in the crimp grip made of PC steel described in Patent Document 3, from the description and drawings of the embodiment after paragraph [0023], the PC steel stranded wire having a diameter of 15.2 mm from seven is used. A sleeve having a diameter much larger than that of the sleeve is fixed, and the ratio (D / d) of the outer diameter D of the sleeve to the outer diameter d of the PC stranded wire in the drawing is about 2.0.
[0013]
In the bridge cable anchoring structure described in Patent Literature 4, although the above effects are expected, a crimping grip in which a thread is machined on the inner peripheral surface of the sleeve is used as a crimping grip attached and fixed to the end of the PC steel stranded wire. For example, in such a crimping grip, there is a concern that stress concentration occurs at the root of the screw, and there is a limit in reducing the thickness of the sleeve, and it is difficult to make the outer diameter of the sleeve thinner. For this reason, there is a limit in making the fixing portion such as a bridge compact.
[0014]
On the other hand, in recent years, for prestressed concrete structures, bridge structures such as suspension bridges, cable-stayed bridges, and the like, cables made of metal wires such as steel wires and stranded wires or composite cables using high-strength low-elongation fibers are used. It is desired that the fixing unit to be installed be lightweight and compact for the purpose of improving the fixing workability. However, the fixing efficiency is maintained as usual and the lightweight and compact structure is used. No applicable structure is found as described above.
[0015]
Therefore, the present invention has been made to solve the above-mentioned problems, and the first object of the present invention is to achieve a fixing efficiency equal to or higher than that of the conventional one, and to be configured to be lightweight and compact. A second object of the present invention is to provide a fixing structure for a wire rod which is lightweight and compactly fixed by employing such a fixing structure for a wire rod end. Is provided.
[0016]
[Means for Solving the Problems]
The present inventors have conducted various investigations and studies on the prior art as described in the section of the prior art in order to achieve the first and second objects. As a result, as the material of the sleeve forming the fixing structure of the end portion of the wire, a relatively strong material other than the carbon steel material for mechanical structure which is conventionally widely used, as described in Patent Document 2, is used. We paid attention to. Then, using a high-strength steel of 800 MPa and 1000 MPa as the material of the sleeve, the end portions of the PC steel stranded wire and the PC steel wire were extruded and pressed in the conventional manner, and the fixing efficiency and the like were investigated.
[0017]
According to the above investigation, by using a high-strength steel sleeve, it is possible to reduce the thickness and weight by reducing the outer diameter while keeping the inner diameter of the insertion hole at the wire end of the sleeve the same, and the fixing part such as the fixing plate is also compact. It turns out that you can do it. However, in the course of the above investigation, if a high-strength steel sleeve is used, the extrusion pressure at the time of extrusion processing for fixing to a wire is increased, and the outer diameter of the sleeve is reduced and the wall thickness is reduced. In combination with the length of the sleeve, it has been found that if the die is not passed smoothly, troubles such as bending or bulging of the sleeve may occur easily. Also, by forming the outer diameter of the high-strength steel sleeve to a smaller diameter and increasing the extruding rate, the pressure can be increased, but this time the fixing plate of the high-strength steel sleeve is used for fixing to the fixing plate. It was found that the fixing strength of the sleeve was insufficient due to swelling of the side and the fixing was not always stable. The present invention has been completed by solving such problems, and has the following structure.
[0018]
That is, according to the present invention (claim 1), in an anchoring structure of a wire end portion in which a high-strength steel sleeve is reduced in diameter and crimped to the wire end portion, the outer diameter D of the crimped high-strength sleeve is equal to the wire diameter. The fixing structure at the end of the wire is characterized in that the fixing is performed at 1.8 times or less the outer diameter d. In this way, by fixing the ratio (D / d) of the outer diameter D of the high-strength sleeve after compression and the outer diameter d of the wire rod to 1.8 times or less, a fixing efficiency equal to or higher than the conventional one can be obtained. As a result, a lightweight and compact fixing structure at the end of the wire is obtained. In this case, the lower limit of the ratio (D / d) is desirably 1.5 times or more. If D / d is less than 1.5 times, fixing efficiency cannot be expected, and bends or swells due to extrusion. This is because there is a concern that such troubles may occur, and furthermore, buckling such as swelling may be caused even after the fixing plate is attached.
[0019]
In the wire end fixing structure according to the first aspect of the present invention, an abrasion material or an insert material as conventionally employed is provided between the outer peripheral surface of the wire end and the inner peripheral surface of the high-strength steel sleeve. It may be configured to have a filler such as (Claim 2). By adopting such a fixing structure of the end portion of the wire, the wire can be expected to be prevented from falling out of the sleeve or to have a buffering effect.
[0020]
The high-strength steel sleeve may have a tensile strength of 800 MPa or more (claim 3). If the tensile strength is 800 MPa or more, the outer diameter can be reduced by about 10% as compared with the conventional carbon steel sleeve for machine structure. For more stable and compact, the tensile strength is desirably 1000 MPa or more. The cross-sectional outer shape of the sleeve is generally circular, but may be circular in the present invention. In particular, when a plurality of sleeves are mounted on the fixing plate, the smaller the spacing between the sleeves, the more compact the fixing. Therefore, the cross-sectional outer shape of the high-strength steel sleeve may be polygonal.
[0021]
According to the present invention (claim 5), the end of the wire rod is inserted into the insertion hole of a high-strength steel sleeve whose outer peripheral surface is formed in a shape along the approach surface of the die and whose outer peripheral surface is tapered in the axial direction. After the insertion, the extruded material is extruded through a die, the diameter of the high-strength steel sleeve is reduced, and the wire is crimped to the end of the wire.
[0022]
According to such a fixing forming method, smooth extrusion can be performed even when the high-strength steel sleeve is extruded, and the maximum diameter portion is extruded due to the axial taper of the outer peripheral surface of the high-strength steel sleeve. Since the outer peripheral surface of the wire is sufficiently pressed and pressed, the wire can be effectively prevented from coming off the sleeve. Then, in order to obtain such an operation and effect more effectively, it is preferable to form the tapered maximum diameter portion so as to be located rearward in the pushing direction of the length of the sleeve. With the taper gradually increasing, improvement in fatigue strength at the sleeve entrance can be expected. In addition, by inserting an abrasion material as a filler between the high-strength steel sleeve and the wire, more effective prevention of detachment can be achieved.
[0023]
Further, in the above-described method for fixing the end portion of the wire rod, it is preferable that a reinforcing tubular body having an inner diameter shape along the cross-sectional outer shape of the high-strength steel sleeve is provided on the outer periphery of the high-strength steel sleeve and extruded. Item 6). By extruding in this way, the extrusion direction of the high-strength steel sleeve is determined, and even if the extrusion load is biased, it can be smoothly extruded.
[0024]
The present invention (claim 7) is a mounting structure for mounting a wire having the wire end fixing structure according to any one of claims 1 to 4 to a fixing plate, wherein the fixing plate penetrates the wire. A fixing structure for a fixed wire, wherein a through-hole and a receiving hole for receiving a sleeve on the fixing plate rear side of the through-hole are provided concentrically. With this mounting structure, even if the outer diameter of the high-strength steel sleeve is formed as small as possible to form the terminal fixing of the wire, the sleeve can be formed on the fixing plate without bulging (buckling). It can be mounted, and the fixing unit can be made compact. In particular, when the anchoring portion is a structure such as a bridge, the anchor portion including the anchor head (fixing plate) can be formed compact (claim 8), and the anchoring portion of the structure can also be made compact. Further, even when the fixing plate is a support plate in a concrete form (claim 9), the fixing device can be formed compactly.
[0025]
Thus, according to the present invention, steel wires, metal wires such as steel strands, as well as carbon fibers, aramid fibers, wire wires such as composite cables using high-strength low-elongation fibers such as glass fibers, A compact fixing structure at the end of the wire can be provided, and the fixing plate (fixing section) of the structure for fixing the end of the wire can be made compact.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view of a fixing structure of an end portion of a wire rod according to the present invention. FIG. 1A is a front sectional view partially showing a cross section, and FIG. 1B is an AA sectional view of a.
[0027]
The fixing structure 1 at the end of the wire rod includes a high-strength steel sleeve 2 having a strength of 1000 MPa and a PC stranded wire 4 in an insertion hole 3 thereof, and has an outer diameter D of the high-strength steel sleeve 2. Is formed to be 1.8 times or less the outer diameter d of the PC stranded wire 4.
[0028]
The fixing structure 1 at the end of the wire is manufactured by extrusion and compression as follows. That is, as shown in FIG. 2, the end of the wire rod of the PC stranded wire 4 is inserted into the processing hole 6 of the extrusion die 5 from the counter extrusion side, and the end of the wire rod is inserted into the insertion hole 3 of the high-strength steel sleeve 2. After that, as shown in FIG. 3, the end face of the high-strength steel sleeve 2 is pressed against the front surface of the processing hole 6 of the extrusion die 5, and the extruding device 7 is operated from the rear surface to move the high-strength steel sleeve 2 to the extrusion die 5. Extruded through the processing hole 6 of FIG. By extruding in this manner, the high-strength steel sleeve 2 is reduced in diameter and pressure-bonded to the PC steel strand 4 inserted into the insertion hole 3.
[0029]
According to the wire end fixing structure 1 having the above-described configuration, the ratio (D / d) of the outer diameter D of the high-strength sleeve after compression and the outer diameter d of the wire is fixed at 1.8 times or less. As a result, a fixing efficiency equal to or higher than that of the related art can be obtained, and a lightweight and compact fixing structure at the end of the wire can be obtained.
[0030]
Incidentally, a high-strength steel sleeve (weight: about 0.18 kg) with an insertion hole diameter of 16 mm and an outer diameter changed was prepared, and a PC steel stranded wire having a diameter of 15.2 mm was extruded from seven of these sleeves into an extrusion die having an extrusion hole diameter of 24 mm. And pressed by extrusion. For comparison, a conventional carbon steel sleeve for machine structural use (weight: about 0.34 kg) having an insertion hole diameter of 16 mm and a changed outer diameter was prepared, and seven of these sleeves were made of PC steel having a diameter of 15.2 mm. The wire was crimped. The fixing efficiencies of the fixing structure 1 according to the present invention and the conventional fixing structure thus pressed were compared. The result is shown in FIG. As is clear from FIG. 4, in the present invention, the ratio (D / d = 1) of the outer diameter (D = 24 mm) of the high-strength steel sleeve after crimping and the outer diameter (d = 15.2 mm) of the PC steel stranded wire. .58) is smaller than the ratio of the conventional sleeve (D / d = 2.0), the fixing efficiency is the same, the outer diameter after crimping is small, the compact size can be achieved, and the weight is reduced (about 50%).
[0031]
As for the strength of the high-strength steel sleeve, as a result of a comparative study of the strengths of 800 MPa and 1000 MPa, after the extrusion processing, the strength of the 800 MPa sleeve increases to nearly 1000 MPa due to work hardening by extrusion, but the strength varies. On the other hand, in the case of the sleeve of 1000 MPa, the strength does not increase so much even when extruded, and there is little variation. In addition, even if the outer diameter of the sleeve is reduced, it is possible to reduce the variation in the fixing efficiency and fix the wire. Further, even when the ratio D / d is about 1.5 times, good fixing efficiency can be secured. Accordingly, the strength of the high-strength steel sleeve may be 800 MPa or more, but is preferably 1000 MPa or more.
[0032]
FIG. 5 is a front sectional view of another embodiment of a fixing structure of an end portion of a wire rod according to the present invention. The wire end fixing structure 8 of this example is different from the wire end fixing structure 1 of the above example in that a filler 9 is filled between the insertion hole 3 of the high-strength steel sleeve 2 and the PC steel strand 4. Otherwise, they have the same configuration. With the configuration in which the filler 9 is inserted as described above, the same effect as that of the above-described fixing structure 1 at the end of the wire can be obtained, and the effect of preventing the wire from slipping out of the sleeve or a buffering effect can be expected. Furthermore, in the case of the present example, when the inner peripheral surface of the insertion hole 3 of the high-strength steel sleeve is reduced in strength in advance, when the filler 9 is used as an abrasive material, The penetration into the peripheral surface is improved, and it can be expected that the fixing efficiency is further increased. In addition, when the wire is a PC steel stranded wire as in this example, an abrasion material can be inserted between the core wire and the side wire of the PC steel stranded wire, and it can be expected that the core wire will not come off from the side wire. .
[0033]
By the way, a high-strength steel sleeve (weight: about 0.17 kg) having an insertion hole diameter of 17 mm and an outer diameter changed was prepared, and a PC steel stranded wire having a diameter of 15.2 mm was prepared from these seven sleeves, and a filler material was provided on the surface. As No. 9, a lubricant was provided, and compression-bonded by extrusion using an extrusion die having an extrusion hole diameter of 24 mm. When the lubricating material is provided and pressure-bonded as described above, the sleeve can be slightly lighter than the fixing structure 1 according to the present invention in which the filler 9 is not provided, and the fixing efficiency can be reduced by a ratio (D / D). According to d), an improvement of 0.1 to 1.5% was observed. In this example, a torsion wire having a triangular cross section was wound in a coil shape and used as an abrasion material as the filler 9.
[0034]
Next, a mounting structure of the wire fixed to the fixing structure 1 at the end portion of the wire having the above configuration will be described with reference to FIG. FIG. 6 is a front sectional view showing a mounting structure in which a plurality of PC steel strands 4 having a wire end fixing structure 1 are mounted on an anchor head (fixing plate). FIG. 7 is an enlarged view of the anchor head of FIG. FIG. 8 is a sectional view taken along the line BB of FIG. 7.
[0035]
The anchor head 11 has a screw formed on the outer peripheral surface, and a fixing nut 12 is screwed to the male screw. In this example, 19 PC steel strands 4 having the above-described wire end fixing structure 1 are attached to the anchor head 11, and after that, the holding plate 13 is attached to the end group of the high-strength steel sleeve 2. After fixing, the cap 14 is attached by screwing to the external thread of the outer peripheral surface of the anchor head 11. An overlap pipe 15 and a main pipe 16 are attached to the outer periphery of the anchor head 11 on the side of the group of PC steel strands 4 to seal the group of PC steel strands 4 attached to the anchor head 11. Then, it is formed into such a structure, and is attached and used via a fixing nut 12 to a fixing portion of a structure (anchor portion of a bridge or the like, etc.) not shown.
[0036]
As shown in FIGS. 7 and 8, 19 through holes 17 for inserting and attaching the PC steel strand 4 are formed in the anchor head 11 in this example. On the back side of the anchor head 11 of the through hole 17, a housing hole 18 having an inner diameter capable of housing the high-strength steel sleeve 2 is formed concentrically, and the high-strength steel sleeve 2 is easily swelled into the housing hole 18. The tip side is accommodated and locked.
[0037]
The depth h of the receiving hole 18 is preferably such that about half the length of the high-strength steel sleeve 2 is buried, and if the depth h is less than 1/10, the portion of the high-strength steel sleeve 2 that receives the most load Comes out of the accommodation hole 18, so that the effect of suppressing the swelling of the portion cannot be expected. On the other hand, the depth h of the accommodation hole 18 may be set to a depth at which the entire length of the high-strength steel sleeve 2 is buried, but depending on the number of PC steel strands 4 attached to the anchor head 11, the thickness of the anchor head 11 is particularly small. Is unnecessarily thick, and the weight cannot be reduced. Further, it is not possible to expect a compact fixing section of a structure not shown, which is formed and attached to such a structure.
[0038]
In the above example, the case where the anchor head 11 is used has been described as an example. However, instead of the anchor head, the through hole 17 and the accommodation hole 18 may be directly formed and attached to a supporting plate such as a concrete formwork.
[0039]
【The invention's effect】
As described above, according to the wire end fixing structure according to the present invention, when the wire is placed in a high-strength steel sleeve, the outer diameter D of the high-strength sleeve after crimping, and the outer diameter d of the wire, By fixing at a ratio D / d = 1.8 or less, fixing efficiency equal to or higher than that of the related art can be obtained, and a lightweight and compact fixing structure at the end of the wire can be obtained.
[0040]
Further, according to the fixing method of the end portion of the wire rod according to the present invention, the high-strength steel sleeve can be smoothly extruded, and furthermore, the high-strength steel sleeve is extruded due to the taper in the axial direction on the outer peripheral surface thereof. Since the maximum diameter portion sufficiently presses and presses the outer peripheral surface of the wire, the wire can be effectively prevented from coming off from the high-strength sleeve even when the wire is crimped at a ratio D / d = 1.8 or less.
[0041]
Further, according to the fixing structure of the fixed wire according to the present invention, even if the outer diameter of the high-strength steel sleeve is formed as small as possible to form the terminal fixing of the wire, the sleeve is expanded. It can be mounted on the fixing plate without causing (buckling), and the fixing unit can be made compact.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a fixing structure of an end portion of a wire rod according to the present invention, wherein a is a front sectional view partially showing a cross section, and b is an AA sectional view of a.
FIG. 2 is an explanatory diagram for explaining a method of fixing and forming a wire end according to the present invention.
FIG. 3 is an explanatory view for explaining a method of forming and fixing a wire end portion according to the present invention.
FIG. 4 shows the ratio D / d and the fixing efficiency between the fixing structure at the end of the wire rod using the high-strength steel sleeve according to the present invention and the fixing structure at the end of the wire rod using a conventional carbon steel sleeve for mechanical structures. FIG. 4 is a graph showing a comparison of the relationship.
FIG. 5 is a front sectional view of another embodiment of a fixing structure of an end portion of a wire rod according to the present invention.
FIG. 6 is a front cross-sectional view showing a mounting structure in which a plurality of PC steel strands having a wire end fixing structure according to the present invention are mounted on an anchor head.
FIG. 7 is an enlarged sectional view of the anchor head of FIG. 6;
8 is a view taken in the direction of arrows BB in FIG. 7;
[Explanation of symbols]
1: Fixing structure of wire rod end 2: High strength steel sleeve 3: Insertion hole 4: PC steel strand 5: Extrusion die 6: Working hole 7: Extruder 8: Fixing structure of wire rod end 9: Filler 11: Anchor head 12: Fixing nut 13: Holding plate 14: Cap 15: Overlap tube 16: Main tube 17: Through hole 18: Housing hole

Claims (9)

In the fixing structure of the end portion of the wire in which the high-strength steel sleeve is reduced in diameter and crimped to the end portion of the wire, the outer diameter D of the high-strength sleeve after crimping is fixed at 1.8 times or less the outer diameter d of the wire. A fixing structure for an end portion of a wire rod characterized by being formed. 2. The fixing structure according to claim 1, further comprising a filler between an outer peripheral surface of the end portion of the wire and an inner peripheral surface of the high-strength steel sleeve. 3. The fixing structure according to claim 1, wherein the high-strength steel sleeve is formed of a steel material having a tensile strength of 800 MPa or more. 4. The fixing structure according to claim 1, wherein the cross-sectional outer shape of the high-strength steel sleeve is polygonal. After inserting the end of the wire into the insertion hole of the high-strength steel sleeve whose outer peripheral surface is formed along the approach surface of the die along the approach surface of the die, and whose outer peripheral surface is tapered in the axial direction, the wire is extruded through the die. A method for forming a fixing at an end of a wire rod, the method comprising reducing the diameter of a high-strength steel sleeve and crimping it to the end of the wire rod. 6. The method for fixing the end of a wire rod according to claim 5, wherein a reinforcing cylindrical body having an inner diameter conforming to the cross-sectional outer shape of the high-strength steel sleeve is provided on the outer periphery of the high-strength steel sleeve and extruded. A mounting structure for mounting a wire having a wire end fixing structure according to any one of claims 1 to 4 on a receiving material, wherein the receiving material has a through hole through which the wire is inserted and a back surface of the receiving material of the through hole. A mounting structure for a fixed wire, wherein a mounting hole for receiving a sleeve is provided concentrically on the side. The fixing structure of a fixed wire according to claim 7, wherein the receiving material is an anchor sleeve of a fixing device. 8. The fixing structure of a fixed wire according to claim 7, wherein the receiving member is a support plate in a concrete formwork.

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