JP2010229598A - Coated wire rope for operation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated wire rope for an operation having sufficient durability of its coat. <P>SOLUTION: A coated wire rope 10 covered with a coat 8 for use in an operation is produced by covering the outer circumference of a wire rope 1 with a resin. The elongation in the length of the ring-shaped coat 8 when ruptured by pressing and extending the same, is at least 83% relative to the circumferential length of the coat 8 before the pressing and extending. The wire rope 1 is fabricated by twisting a plurality of strands 2. The coat 8 is formed by extrusion-molding a resin. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a coated wire rope for operation in which an outer periphery of a wire rope is coated with a resin.

  2. Description of the Related Art Conventionally, as disclosed in Patent Document 1, there is known a coated wire rope for operation in which a coating made of resin is formed on the outer periphery of a wire rope obtained by twisting a plurality of side strands around a core strand.

  When forming the coat, a wire rope is passed through the mold and molten resin is injected into the mold. The molten resin is injected into the mold from a direction substantially orthogonal to the wire rope, and the molten resin flows along the outer periphery of the wire rope in the mold to cover the outer periphery of the wire rope. At that time, the molten resin flows to the outer circumference of the wire rope so as to wrap around the outer circumference of the wire rope from both the left-handed and right-handed sides, and merges on the opposite side to the injection side. Line marks along the direction may occur.

JP 2008-303493 A

  In such a conventional coated wire rope for operation, sufficient durability is obtained when the coating is formed with the molten resin, and the molten resin is appropriately joined even at the junction, so that the weld line cannot be visually determined. It becomes so. However, if the coat is not properly formed, sufficient durability cannot be obtained. In particular, the molten resin does not properly join at the joining point, and the strength of the joining point becomes lower than other parts. .

  For example, if a coated wire rope for operation is wrapped around a pulley and a load is applied repeatedly, cracks will occur in the coat along the weld line at the merge point, and water will invade from that point, causing corrosion of the wire rope. Also, the peeled coat may be entangled or caught on other members, which may cause operational problems.

  An object of the present invention is to provide a coated wire rope for operation having sufficient coat durability.

In order to achieve this problem, the present invention has taken the following measures in order to solve the problem. That is,
In the coated wire rope for operation in which the outer periphery of the wire rope is coated with a resin to form a coat,
The coated wire rope for operation is characterized in that the coat has an elongation rate of 83% or more with respect to the circumference of the coat before spreading when the ring-shaped coat is spread and broken. . The wire rope may be formed by twisting a plurality of strands. The coat may be formed by extrusion molding of the resin.

  The coated wire rope for operation of the present invention has a durability equivalent to 100,000 times or more of the durability test if the ring-shaped coat is spread and formed so that the elongation at break is 83% or more. Since the measurement is performed by expanding the ring-shaped coat, the weld line breaks from the weld line when the weld line is weakest, regardless of where the weld line is formed. As a result, it is possible to easily determine whether or not appropriate extrusion has been performed.

It is an expanded sectional view of the covered wire rope for operation as one embodiment of the present invention. It is a front view of the test apparatus which measures the elongation percentage of the coat of this embodiment. It is a top view of the testing apparatus which measures the elongation percentage of the coat of this embodiment. It is explanatory drawing which measures the elongation rate of the coat of this embodiment. It is explanatory drawing of the durability test of the coated wire rope for operation in this embodiment. It is a fragmentary sectional view of the pulley used for the durability test of the covered wire rope for operation in this embodiment. It is a graph which shows the relationship between the elongation rate of the coat of this embodiment, and durability.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, reference numeral 1 denotes a wire rope, and the wire rope 1 is formed by twisting a large number of strands 2. As a material for the strands 2, a steel wire or a SUS wire is used. In addition, a surface treatment such as galvanization may be performed.

  As shown in FIG. 1, the wire rope 1 of the present embodiment has eight side strands 6 in which six strands 2 are twisted around a core strand 4 in which nineteen strands 2 are twisted. They are formed together. In this embodiment, the outer diameter of the wire rope 1 is formed to 1.5 mm.

  The outer periphery of the wire rope 1 is coated with a resin to form a coat 8, and the wire rope 1 and the coat 8 form a coated wire rope 10 for operation. In the present embodiment, the outer diameter of the coat 8 is formed to 2.1 mm. In this embodiment, nylon 11 is used for the resin of the coat 8, and the mechanical properties of nylon 11 are as follows: tensile yield strength is 42 MPa, elongation at that time is 8%, and tensile fracture strength is 53 MPa. The elongation at that time is 300%. The Rockwell hardness is 108R and the Shore hardness is 72D. The resin is not limited to nylon 11, but may be other polyamide resin such as nylon 12 or nylon 66, polyethylene, or the like.

  The wire rope 1 is covered with resin by extrusion molding, and the wire rope 1 is passed through a mold (not shown) and molten resin is injected into the mold. The molten resin is injected into the mold from a direction substantially orthogonal to the wire rope 1, and the molten resin flows along the outer periphery of the wire rope 1 in the mold to cover the outer periphery of the wire rope 1.

  At that time, the molten resin flows on the outer circumference of the wire rope 1 so as to wrap around the outer circumference of the wire rope 1 from both the left and right sides, and merges on the opposite side to the injection side. A line may occur along the longitudinal direction of the wire rope 1.

  The coat 8 is formed such that the elongation when the ring-shaped coat 8 is expanded and broken is equal to or greater than 83% with respect to the coat circumference before being expanded. Next, the elongation rate will be described in detail.

  Elongation rate is the ratio to the coat circumference before spreading, which is stretched until the coat 8 is spread and broken, from the coated wire rope 10 for operation in which the wire rope 1 is coated with a resin to form the coat 8, Strip coat 8 into a ring. For example, from the end of the coated wire rope for operation 10, it is cut along the entire circumference with a blade so that the axial width is 2 mm, and is extracted from the wire rope 1 in a ring shape. The width in the axial direction is not limited to 2 mm, and may be determined as appropriate.

  The ring-shaped coat 8 having an axial width of 2 mm is mounted on the test apparatus 21 shown in FIGS. The test apparatus 21 includes a conical portion 22, and the conical portion 22 has a tip-side diameter of 1 mm, a root-side diameter of 10 mm, a length of 46 mm therebetween, and a taper angle θ of approximately 11 mm. It is formed at 4 degrees.

  The conical portion 22 is formed at a taper angle θ that allows the link-like coat 8 to be spread almost radially outward in the entire width range. When the taper angle θ is too large, when the coat 8 is pushed in, the front side of the pushed coat 8 is first spread and broken so that the test repeatability and the measurement result of the length L2 are reduced. The difference may be reduced and accurate testing may not be possible.

  In this embodiment, since the inner diameter of the ring-shaped coat 8 is the same as the outer diameter of the wire rope 1, 1.5 mm, the tip diameter of the conical portion 22 is set to 1 mm, but depending on the inner diameter of the coat 8 to be measured. What is necessary is just to make it change so that taper angle (theta) of the cone part 22 may become substantially the same.

  The ring-shaped coat 8 is inserted from the tip of the conical portion 22 as shown in FIG. Then, until the coat 8 is broken, the coat 8 is pushed into the conical portion 22 so that a pressing force is evenly applied in the circumferential direction. For example, the coat 8 spreads in the radial direction as the coat 8 is pushed into the conical portion 22. Accordingly, jigs having various circular holes with different diameters are prepared, and the holes of the jigs are changed as the diameter increases, so that the coat 8 is pushed evenly in the radial direction. In this embodiment, the indentation speed was 0.5 mm / s, and the ambient temperature during the test was 25 ° C. The test is preferably performed under the same conditions.

  When the coat 8 is pushed into the conical portion 22 and the coat 8 is broken, the length L2 of the broken coat 8 is immediately measured as shown in FIG. The ratio of the circumference of the coat 8 before spreading to the length when the ring-shaped coat 8 is expanded and broken is calculated as the elongation. The elongation percentage indicating the change in the length of the coat 8 before and after breaking at the time of this measurement is calculated by the following calculation formula.

Elongation rate (%) = (L2-L1) / L1 × 100
Here, L1 is the length of the coat 8 before spreading, and is calculated by the following calculation formula. That is, L1 is calculated by setting the intermediate diameter between the inner diameter and the outer diameter of the coat 8 as the diameter, and the circumference of the intermediate diameter as the length of the coat 8. Alternatively, the ring-shaped coat 8 may be cut out from the wire rope 1 and cut in one place in the axial direction to measure the length L1 of the coat 8 before being spread. L2 is an actual measurement value of the above-described length of the coat 8 immediately after fracture.

L1 = (actually measured outer diameter of wire rope 1+ (actually measured outer diameter of coat 8−actually measured outer diameter of wire rope 1) / 2) × π
Next, the durability test of the coated wire rope 10 for operation will be described with reference to FIG.

  First, one end of the operation covered wire rope 10 is connected to the rod of the air cylinder 30. After that, after being wound around the first pulley 32 by 180 degrees, the second pulley 34 is wound around 90 degrees and then drawn downward. After passing the operation covered wire rope 10 through the through hole 38 of the stopper plate 36, the weight 40 is attached to the end of the operation covered wire rope 10.

  As shown in FIG. 6, the first pulley 32 and the second pulley 34 had a pulley diameter of 28 mm, a pulley groove with a radius of 1.15 mm, and a groove angle of 20 degrees. The weight 40 has a weight of 98 N, the air cylinder 30 is driven at a speed of 0.33 Hz and a stroke of 100 mm. When the weight 40 is pulled up, the weight 40 is abutted against the stopper plate 36 so that an overload of 343N is applied to the operation covered wire rope 10 for 0.5 seconds.

  The air cylinder 30 is reciprocated to measure the number of reciprocations until a crack occurs in the coat 8 of the coated wire rope 10 for operation, and the number of times until the coat crack occurs is taken as the result of the durability test.

  About six types of Examples 1-6 in which the coat 8 of the coated wire rope 10 for operation is different, the elongation rate and the durability test were performed, and the results of both were compared. Table 6 below shows six different types of Examples 1 to 6. In Examples 1-6, the screw rotation speed of the screw feeder which injects the molten resin of the extrusion molding machine which is not illustrated into a metal mold is changed, the rotation speed of Example 6 is set to 1, and Examples 1-5 are the It is shown as a ratio to the rotational speed.

これらの実施例１〜６の操作用被覆ワイヤロープ１０についての伸び率と耐久性試験との結果を表２に示す。実施例１〜５では同じ３本の操作用被覆ワイヤロープ１０について試験を行い、実施例６については同じ４本の操作用被覆ワイヤロープ１０について試験を行い、伸び率についてはそれぞれ平均値を示した。また、表２の結果については、図７にグラフとして示す。

Table 2 shows the results of the elongation and the durability test for the coated wire rope 10 for operation of Examples 1 to 6. In Examples 1 to 5, the same three coated wire ropes for operation 10 were tested, and in Example 6, the same four coated wire ropes for operation 10 were tested. It was. Moreover, about the result of Table 2, it shows as a graph in FIG.

この結果から、伸び率と耐久性試験とには相関があり、コート割れ回数１０万回を達成できるコート８の伸び率は８３％以上であることがわかる。即ち、実施例３の形成条件でコート８を形成し、そのときのコート８の伸び率を測定して、伸び率が８３％あれば、耐久性試験でコート割れ回数１０万回を達成できる。実施例４〜６のように、伸び率が８３％以上あれば、コート割れ回数は１０万回以上を達成できる。

From this result, it can be seen that there is a correlation between the elongation rate and the durability test, and the elongation rate of the coat 8 capable of achieving 100,000 coating cracks is 83% or more. That is, when the coat 8 is formed under the formation conditions of Example 3 and the elongation percentage of the coat 8 at that time is measured and the elongation percentage is 83%, the number of coating cracks can be achieved 100,000 times in the durability test. As in Examples 4 to 6, if the elongation is 83% or more, the number of coat cracks can be 100,000 or more.

  Further, in this embodiment, the resin of the coat 8 is nylon 11, but as described above, the mechanical properties of the nylon 11 are that the tensile fracture strength is 53 MPa and the elongation at that time is 300%. From this, in the six types of Examples 1 to 6, the elongation does not reach 300% and is broken before that. That is, the weld line breakage has a significant effect on the elongation results.

  In the above-described test, the link-like coat 8 is attached to the conical portion 22 of the test apparatus 21 and spreads until it breaks, so that the measurement of the length L2 when the weld line breaks is affected. Not give. That is, even if the position of the weld line cannot be visually confirmed, the length L2 can be measured regardless of this.

  As described above, the coat 8 may be formed such that the ring-shaped coat 8 is expanded and the elongation percentage when broken is 83% or more. It is not necessary to conduct a durability test for several hundred thousand times on each coat 8, and the durability of the coat 8 can be easily confirmed. Further, after forming the coated wire rope 10 for operation, a part of the coat 8 at the end is cut off, and the above-described elongation is measured. If the result is 83% or more, the durability test is 100,000. It can be seen that it has the same durability as the number of times.

  Further, after forming the coated wire rope 10 for operation, a part of the coat 8 at the end is cut off, and the above-described elongation is measured. If the result is 83% or more, the durability test is 100,000. It can be seen that it has the same durability as the number of times. Even if the coat 8 is cut off, the coated wire rope 10 for operation can be used, so that it is possible to measure the elongation of each product to be shipped and store it as data.

  Further, since the measurement is performed by expanding the ring-shaped coat 8, no matter where the weld line is formed, if the weld line is weakest, the weld line breaks from the weld line. It can be determined whether or not proper extrusion has been performed.

  The present invention is not limited to such embodiments as described above, and can be implemented in various modes without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Wire rope 2 ... Elementary wire 4 ... Core strand 6 ... Side strand 8 ... Coat 10 ... Operation | use covering wire rope 21 ... Test apparatus 22 ... Conical part 30 ... Air cylinder 32, 34 ... Pulley 36 ... Stopper plate 38 ... Through Hole 40 ... Weight

Claims (3)

In the coated wire rope for operation in which the outer periphery of the wire rope is coated with a resin to form a coat,
The coated wire rope for operation characterized in that the coat has an elongation percentage of 83% or more with respect to the coat circumference before the ring-shaped coat is expanded and broken when broken. The covered wire rope for operation according to claim 1, wherein the wire rope is formed by twisting a plurality of strands. The coated wire rope for operation according to claim 1, wherein the coat is formed by extrusion molding of the resin.

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