JPH0770962A - Wire rope - Google Patents

Abstract

PURPOSE:To provide a wire rope, capable of sufficiently satisfying various properties such as nonrotating properties, fatigue and shape collapse resistances and winding properties on a drum, sufficiently adaptable to multilayer winding cargo working and construction machines at a high lift and excellent in practicality. CONSTITUTION:This wire rope has a fibrous core 4 and a core strand 3 laid around the fibrous core and plural side strands 9 laid in the same twisting direction as that of the core strand and is formed by stranding the plural side strands in the twisting direction opposite to those of the core strand and side strands. The pitch multiple of the rope is larger than that of the side strands.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire rope for use in cranes, hoists and the like, which is highly applicable to cargo handling machine applications with a high lift and multi-layer winding and construction machine applications, and is excellent in practicality. .

[0002]

2. Description of the Related Art As wire ropes used in cargo handling machines such as cranes and hoists and construction machines, JIS is generally used.
IWRC 6xFi specified in the standard (JIS G 3525)
(29), 6-strand ropes such as IWRC 6 × WS (31), flat-type strand ropes, and multi-layer strand ropes, and the rope diameter is mainly 8 to 20 mm.

During use, this type of wire rope is subjected to actions such as repeated bending due to sheaves, load at high lift, fluctuating load due to unloading, repeated winding on a winch drum, and strong rubbing between ropes. . Therefore, it is desired that the wire rope has excellent fatigue resistance, as well as good winding-up property on the drum and good deformation resistance.

In particular, when a tension is applied to the wire rope due to a suspended load or the like, a torque is generated in the rope which tends to rotate in the direction in which the twist returns. A wire rope is required to have a small torque and a property of being hard to rotate, that is, excellent in non-rotating property.

In the currently used rough terrain crane, H / D is about 90 with four suspensions, and the theoretical pullback torque coefficient K is required to be 58 × 10 ⁻³ or less. Non-rotating ropes with extended pitch and reduced strand pitch are supplied.

[0006]

However, in recent years,
As the height of rough terrain cranes increases, in the future, the suspension height will be approximately 26m (H
There is a strong demand from customers for the development of wire ropes that can handle up to about / D = 110). In such a high lift lifting application, the pullback torque coefficient K is set to 45 × 10.
^Since it is required to be ^-3 or less, the conventional wire rope cannot meet this demand.

This kind of wire rope is subjected to the effects of repeated bending by sheaves, load at high lift, fluctuating load due to unloading, repeated winding on a winch drum, and strong rubbing between ropes. Therefore, the rope is required to have durability against these effects. That is, it is desired that the fatigue resistance is excellent, and the winding property and the deformation resistance when the drum is wound are good.

When tension acts on the rope due to a suspended load or the like, a torque is generated in the rope to rotate in the direction in which the twist returns, but the pullback torque is small and the rope does not rotate easily. Need to be excellent.

However, the conventional 6-strand wire rope is good in terms of fatigue resistance, windability on a drum, and shape collapse resistance, but is inferior in non-rotating property, so that it can be lifted at high lift. Entanglement is likely to occur during work. In order to improve this non-rotation property, it is conceivable to further lengthen the rope pitch in the 6-strand wire rope. However, if the rope pitch is lengthened, the non-rotation property will improve, but the windability on the drum will decrease. Will end up. Further, when the twisting direction of the core rope is opposite to the twisting direction of the rope, the non-rotating property is improved, but there is an inconvenience that the shape collapse resistance is lowered due to the unbalance of the twisting.

In the conventional flat-type strand rope, although the non-rotating property is good, a small center is inserted in the strand, the strand is deformed, and the rope pitch is long. Inferior in winding property and shape collapse resistance.

On the other hand, the conventional multi-layered strand rope has good non-rotational property and shape collapse resistance, but has poor fatigue resistance and high manufacturing cost. As described above, in the conventional wire rope, it is difficult to simultaneously satisfy various characteristics such as non-rotational property, fatigue resistance, windability on a drum, and shape collapse resistance. In addition, it is becoming difficult to adapt to multi-layered cargo handling machine applications and construction machine applications.

The present invention has been made by paying attention to such a point, and its purpose is to provide non-rotational property, fatigue resistance, windability on a drum, and shape collapse resistance. Both of them are well maintained and can be sufficiently applied to cargo handling machine applications of multi-winding with a high lift and construction machine applications, and H / D = 110 (pullback torque coefficient K required to increase the lift of a rough terrain crane). Is 45 × 10 ⁻³ or less), and it is to provide a wire rope excellent in practicability.

[0013]

A wire rope according to the present invention comprises a fiber core, a core strand in which a plurality of wires are twisted around the fiber core, and a plurality of strands twisted in the same direction as the twist of the core strand. With a side strand of the book, a plurality of side strands are twisted in the opposite direction to the twist of the core strand and the side strand to form a rope, and, of the pitch multiple of the rope than the pitch multiple of the side strand. It is characterized by being larger.

The outer diameter ratio of the core strands to the side strands is preferably in the range of 1.04 to 1.18. By setting the outer diameter ratio of both to such a range,
The wire rope is excellent in fatigue resistance and flexibility, has a small torque coefficient K, and is excellent in non-rotational property and has a good property balance as a whole.

Since the IWSC is generally inferior to the IWRC in flexibility, in the present invention, the number of constituent wires of the IWSC is specified as follows, using the core wire as the fiber core. If the number of strands is too small, the flexibility of the rope is impaired, causing a problem in flexibility. On the other hand, if the number of strands is too large, each strand becomes too thin and wear resistance is impaired, resulting in a problem of wear of the strands due to fretting. The number of strands is 6 ≦ N ₁
By defining ≤18 and 12 ≤N ₂ ≤24 respectively, both flexibility and fretting of the rope can be satisfied. This is because if the number N _{1 of} strands is less than 6, flexibility deteriorates, and if the number N ₁ is more than 18, the wire diameter becomes too thin and it becomes difficult to twist the strands together. Also, if the number of strands N ₂ is less than 16, the flexibility deteriorates, and if it exceeds 24, the wire diameter becomes too thin, causing the problem of fretting, and the flexibility becomes excessive. Because it will be.

Further, the number of side strands is 4 to 8, and it is preferable that each side strand is formed by twisting 20 to 55 element wires. In this case, the rope diameter is preferably 6 to 30 mm. This is because if the rope diameter exceeds 30 mm, the flexibility of the rope deteriorates, and if the rope diameter falls below 6 mm, it becomes difficult to secure a satisfactory non-rotating property.

[0017]

In the wire rope according to the present invention, a plurality of side strands are twisted in the direction opposite to the twist of the core strand and the side strand to form a rope, and the pitch of the rope is larger than the pitch multiple of the side strand. Since the multiple is made larger, the direction of the torque generated in the core when tension is applied to the rope and the direction of the torque generated in the outer layer are opposite to each other and cancel each other out. Even if it is a multi-layer winding, it hardly rotates on its own.

Further, by setting the outer diameter ratio of the core strands to the side strands in the range of 1.04 to 1.18, the non-rotating property can be further improved. Furthermore, since the fiber core is inserted in the core strand, the flexibility of the rope is improved, which effectively prevents the fatigue resistance of the rope, winding on the drum, and deterioration of shape resistance. To be done.

In this case, since the number of strands of the core strand is set to a predetermined value, both flexibility and fretting of the rope are well balanced, and a rope having excellent durability can be obtained.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the present invention will be described below with reference to the accompanying drawings. A first embodiment will be described with reference to FIGS. 1 and 2. The wire rope 2 of the first embodiment is an IWS formed by twisting six side strands 9 around the outer periphery of a core strand 3 to form an outer layer portion 8.
It has a configuration of C6 × WS (31).

The core strand 3 is formed by twisting a plurality of wires around the outer periphery of the fiber core 4 in parallel to form a three-layer structure. The fiber core 4 is made of synthetic fiber such as polypropylene or natural fiber such as Manila hemp, and its outer diameter is 10 to 50% of the outer diameter of the core strand 3. The twist pitch of the core strand 3 is 5 to 8 times its outer diameter. Then, the twist direction of the core strand 3 and the side strand 9
In the case where the twisting directions of the outer layer portion 8 composed of 1 are opposite to each other, that is, when the core strand 3 is S twisted, the outer layer portion 8
Is normally Z twisted.

In the wire rope 2 having such a structure, since the twisting direction of the core strand and the twisting direction of the outer layer portion 8 are opposite to each other, when the rope 2 is tensioned, the core strand is twisted. The direction of the torque generated in 3 and the direction of the torque generated in the outer layer portion 8 are opposite to each other and cancel each other out. Therefore, the rope practically hardly rotates even at a high lift.

Further, since the fiber core 4 is inserted in the core strand 3, the flexibility of the rope 2 is improved, which results in the fatigue resistance of the rope 2 and the windability on a drum.
It is possible to keep various properties such as the deformation resistance.

Next, referring to Table 1, the ropes of Examples 1 to 4 will be described in comparison with those of Conventional Examples 1 and 2 and Comparative Examples 1 and 2, respectively. IWRC6 as conventional examples 1 and 2
A wire rope having a structure of × WS (31) and a rope diameter d of 16 mm was prepared as IWSC6 as Examples 1 to 4 and Comparative Examples 1 and 2.
A wire rope having a × WS (31) structure and a rope diameter d of 16 mm was tested. In the conventional examples 1 and 2, the outer diameter ratios of the core rope and the side strands are 1.23 and 1.09, respectively.
However, this is an empirically set value because the twisting configuration of the core rope is different.

In Examples 1 to 4 and Comparative Example 2, the outer diameter ratio between the core strand and the side strand of Comparative Example 1 was used as a reference (1.
00), the outer diameter ratio of each is 1.03, 1.0
6, 1.09, 1.12, 1.15. [Twisting direction] In Conventional Examples 1 and 2, the core rope is Z-twisted, the side strand is S-twisted, and the entire rope is Z-twisted (Z / S /
Z). In Examples 1 to 4 and Comparative Examples 1 and 2, the core rope is S-twisted, the side strands are S-twisted, and the entire rope is Z-twisted.
It was twisted (S / S / Z). [Pitch multiple] The twist pitch multiple in the conventional example 1 is 6.5 times the diameter of the core rope and 7.
Eight times the rope was 6.2 times its diameter. Conventional example 2,
In Examples 1 to 4 and Comparative Examples 1 and 2, the core rope (core strand) is 6.5 times its diameter, the side strand is 5.0 times its diameter, and the rope is 7.5 times its diameter. And In Conventional Example 2, Examples 1 to 4, and Comparative Examples 1 to 2, the rope pitch multiple is set larger than the side strand pitch multiple. [Torque Coefficient K] The torque coefficient K shown in Table 1 is an index obtained by using the following equation (1), and the smaller the value of the torque coefficient K, the more difficult it is for the rope to rotate.

K = T / (W × D) (1) where W is the tension applied to the rope (N), T is the torque due to the tension W (N · m), and D is the rope outer diameter (m). Represent.

As is clear from Table 1, the torque coefficients K of the ropes of Examples 1 to 4 and Comparative Examples 1 and 2 are lower than those of the conventional examples 1 and 2, and it is difficult for any of the ropes to rotate. The result is that it is a thing. [Flexibility] The flexibility shown in Table 1 was evaluated by supporting the rope between spans of 400 mm and measuring the amount of flexure (mm) when a load of 3 kg was applied to the midpoint. . Conventional example 1
The results were evaluated as a standard (100%) for comparative evaluation. In Comparative Example 1, the results were below the reference value of Conventional Example 1, but in Examples 1 to 4 and Comparative Example 2, results were equal to or higher than those of Conventional Examples 1 and 2. [Bending Fatigue Property] The fatigue property shown in Table 1 shows the result of the repeated bending fatigue test of the rope. The repeated bending fatigue test is based on the S bending test method, and the conditions thereof are that the coefficient (D / d) is 20 and the safety factor Sf is 5.
The time when 10% of the total wire was broken in one pitch of the rope was judged as the life of the rope, and evaluated by the number of repeated bendings (the number of cycles) applied up to that time. The results of Conventional Example 1 were used as a reference (100%) for comparative evaluation. Comparative Examples 1 and 2 were below the reference value of Conventional Example 1, but Examples 1 to 4 were all higher than the reference value of Conventional Example 1.

[0028]

[Table 1]

The wire rope of the above-mentioned embodiment has a small torque coefficient K, and good non-rotating characteristics can be obtained in a high-lift crane with H / D = 110. Further, when the outer diameter ratio of the core strands to the side strands is set in the range of 1.04 to 1.18, the flexibility and fatigue resistance are good at the same level of quality as conventional products, and the drum is good. It is possible to favorably retain the winding property and the shape-deformation resistance at the same time, and it is possible to set the torque coefficient K to 45 × 10 ⁻³ or less.

Next, referring to FIG. 3 and FIG.
An example will be described. The core strand 3 of the wire rope 2 is covered with a resin coating layer 7, six side strands 9 are twisted around the outer periphery thereof, and an outer layer portion 8 is formed by these six side strands 9. That is, the wire rope 2 has a structure of IWSC6 × WS (31).

The core strand 3 is formed by twisting a plurality of wires 5 around the outer circumference of the fiber core 4. The fiber core 4 is made of synthetic fiber such as polypropylene or natural fiber, and its outer diameter is 10 to 50% of the outer diameter of the core strand 3.
Moreover, the pitch of the twist of the core strand 3 is 5 to the outside diameter.
Eight times.

The twisting direction of the outer layer portion 8 consisting of the six side strands 9 is opposite to the twisting direction of the core strand 3. That is, when the core strand 3 is S twisted,
The outer layer portion 8 is Z twisted.

The core strand 3 is covered with a resin coating layer 7. The resin coating layer 7 is made of a thermoplastic polymer resin such as polyethylene, and its average thickness is preferably 0.3 to 0.9 mm.

In the wire rope 2 having such a structure, the direction of the torque generated in the core strand 3 when the tension is applied to the rope and the direction of the torque generated in the outer layer portion 8 cancel each other out, so that the high lift is high. However, the rotation does not substantially occur. Further, since the core strand 3 is coated with the thermoplastic polymer resin, there is almost no risk of the core strand 3 jumping out of the rope.

Next, the case of producing a 6-strand rope will be described with reference to FIGS. 5 and 6. A steel wire defined in JIS G3525 was used as the wire. The average diameter of the wire is about 0.70 mm. 2.2 in the fiber core 4
A polypropylene fiber having a diameter of 4 mm was used. The resin coating layer 7 was formed using the extruder 11 shown in FIG. Using the twisting machine 20 shown in FIG.
twisted into a. [Formation of core portion] The fiber core 4 is fed at a predetermined speed toward the winding machine of the winding portion while unwinding from the reel of the feeding portion. A voice is provided in the feeding path, and in addition to the fiber core 4, a large number of strands are fed toward the voice from the swift of the sending portion. These strands are twisted in an S twist around the outer periphery of the fiber core 4 to form the core strand 3. The average twist pitch of the core strand 3 is 3
The core strand 3 has an average diameter of 5.45 mm. [Resin coating treatment] As shown in FIG. 5, the core strand 3 serving as the core portion 3a is inserted into the lower cast portion 15 of the extruder 11, and the molten resin 7a is drawn while the core strand 3 is being pulled out from the cast portion 15. Attach to the outer circumference of 3. The extruder 11 has a spiral extrusion rod 14 in a cylinder 12, and the molten resin 7 a in the cylinder 12 is supplied under pressure to a cast part 15. Polyethylene was used as the resin 7a for the covering material.

The outlet 17 of the cast part 15 has a diameter slightly larger than that of the inlet 16, and when the core strand 3 is pulled out from the cast part 15, a desired amount of the molten resin 7a adheres to the periphery of the core strand 3 and has a desired thickness. The resin coating layer 7 is formed. In this embodiment, the resin coating layer 7 having an average thickness of 0.6 mm is adhered and formed around the core strand 3 by adjusting the drawing speed, the diameter of the outlet 17 and the resin temperature to form the resin coating core portion 3a. [Rope Twisting] The twisting wire machine 20 is provided between the swift of the feeding section and the winder of the winding section, and tension control is performed so that a predetermined tension is applied to each strand that is continuously fed. ing.

As shown in FIG. 6, the end plate 2 of the twisting machine 20
2, a preform device 23 is attached. A fixed frame 24 is provided immediately downstream of the preform device 23.
A voice 25 is attached to the.

The resin-coated core portion 3a is provided at the center of the twisting machine 20.
And the side strands 9 are shaped (preformed) by the preforming device 23, and these are formed into the voice 2
5 is twisted on the core portion 3a. The twist direction is Z twist.

Here, the shaping means that the strands are subjected to a stress equal to or more than the elastic limit before being twisted by the voice 25, and are preformed so as to have the same shape as the spiral of the twisted strands.

When exiting the voice 25, the 6-strand rope 2 is obtained. The final finished diameter of rope 2 is 16 mm. The twist pitch of the side strands 9 was 120 mm, and the pitch multiple was 7.5 times the rope diameter D.

In the above embodiment, the case of manufacturing a 6-strand wire rope has been described, but other wire ropes such as a flat strand rope or a multi-layer strand rope can be manufactured.

[0042]

EFFECTS OF THE INVENTION According to the wire rope of the present invention, since the properties of non-rotational property, fatigue resistance, windability on a drum, and shape collapse resistance are all satisfied, it is suitable for multi-winding cargo handling machines with high lift. It can be fully adapted for construction and construction machinery.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a wire rope according to a first embodiment of the present invention.

FIG. 2 is a partial cutaway view of the wire rope of the first embodiment.

FIG. 3 is a transverse sectional view showing a wire rope according to a second embodiment of the present invention.

FIG. 4 is a partial cutaway view of the wire rope of the second embodiment.

FIG. 5 is a partial sectional view showing a main part of an apparatus for coating a core strand with resin.

FIG. 6 is a view showing a main part of an apparatus for twisting side strands in opposite directions on resin-coated core strands.

[Explanation of symbols]

3 ... Core strand, 4 ... Fiber core, 5 ... Wire, 7 ... Resin coating layer, 8 ... Outer layer portion, 9 ... Side strand

Claims (4)

[Claims] 1. A fiber core, a core strand in which a plurality of wires are twisted around the fiber core, and a plurality of side strands twisted in the same direction as the twist of the core strand. The side strands are twisted in a direction opposite to that of the core strands and the side strands to form a rope,
Moreover, the wire rope is characterized in that the pitch multiple of the rope is larger than the pitch multiple of the side strand. 2. The wire rope according to claim 1, wherein the outer diameter ratio of the core strands to the side strands is in the range of 1.04 to 1.18. 3. The core strand is SeS (a + N ₁ ) + N.
₂ and the number of strands N ₁ and N ₂ is 6 ≦ N, respectively.
₁ ≦ 18, 12 ≦ N ₂ ≦ 24, (a + N ₁ )
_2. The wire rope according to claim 1, wherein N ₂ is twisted on top of twisted together. 4. The wire according to claim 1, wherein the number of side strands is 4 to 8, and each side strand is formed by twisting 20 to 55 strands. rope.