WO2017131288A1

WO2017131288A1 - Wire rope for elevator

Info

Publication number: WO2017131288A1
Application number: PCT/KR2016/003636
Authority: WO
Inventors: Yeon Hwan BAE
Original assignee: Kiswire Ltd.
Priority date: 2016-01-28
Filing date: 2016-04-07
Publication date: 2017-08-03
Also published as: CN108602646B; KR101843142B1; CN108602646A; KR20170090171A; JP2019503322A; JP6625241B2

Abstract

Provided is an elevator wire rope in which fiber cores having a high grease content are arranged in an empty space between center strands and inner-layer strands or an empty space between the center strands to improve flexibility while maintaining properties such as high elasticity and low elongation. The wire rope includes: a rope core including center strands and fiber cores, each of the center strands being formed by twisting wires; inner-layer strands each formed by twisting wires, the inner-layer strands being arranged around the rope core; and outer-layer strands each formed by twisting wires, the outer-layer strands being arranged around the inner-layer strands. The inner-layer strands are ten in number, and the outer-layer strands are ten in number. The fiber cores are arranged in at least one of an empty space between the center strands and the inner-layer strands and an empty space between the center strands.

Description

WIRE ROPE FOR ELEVATOR

One or more embodiments relate to a wire rope for an elevator, and more particularly, to an elevator wire rope in which fiber cores having a high grease content are arranged in an empty space between center strands and inner-layer strands or an empty space between the center strands so that the flexibility of the wire rope is improved while properties of the wire rope such as high elasticity and low elongation are maintained.

In general, metal wire ropes are widely used in many applications such as machines, constructions, ships, fishing, mining, bridges, cableways, and elevators. FIG. 1 is a view illustrating a basic structure of a wire rope 10.

Referring to FIG. 1, the wire rope 10 of the related art includes an inner core 20 and outer-layer strands 30 twisted around the inner core 20. Each of the outer-layer strands 30 is formed by twisting a plurality of wires 32 around a core wire 31 at a certain pitch. In the wire rope 10 illustrated in FIG. 1, the outer-layer strands 30 form a single layer. However, the outer-layer strands 30 may form a plurality of layers.

Tension may act on the wire rope 10 of the related art due to a load applied to the wire rope 10 in the length direction of the wire rope 10, or while the wire rope 10 slips or slides in a sheave, a load may be repeatedly applied to the wire rope 10 which causes the wires 32 of the outer-layer strands 30 to rub against each other. Thus, the wire rope 10 may have a short fatigue life. In addition, if an anti-corrosion plating layer of the wire rope 10 is damaged, the wire rope 10 may rust, and thus, a lubricant such as grease is applied to the wire rope 10.

A wire rope of the related art may include a grease-containing core, and grease may be supplied to outer-layer strands from the grease-containing core. There are two types of cores: a fiber type and a steel type.

Fiber cores may contain a relatively large amount of grease and thus may improve the flexibility of wire ropes. However, fiber cores have poor mechanical properties such as low fracture strength and high elongation.

Steel cores may be classified into two types: an independent wire rope core (IWRC) type in which a core is located in a wire rope center region, and a center fit rope core (CFRC) type in which IWRC strands are arranged between inner sides of outer-layer strands. Since steel cores are formed of steel, steel cores have good mechanical properties such as high fracture strength, low elongation, and low deformation in rope shape. For example, CFRCs have a high metal cross-sectional area and are thus widely used in wire ropes for high-rise building elevators. However, compared to fiber cores, steel cores contain a relatively small amount of grease and thus have a low degree of flexibility.

Recently, the construction of very high buildings has increased, and thus the demand for ropes for elevators for very high buildings has also increased. Since elevators in very high buildings are operated within a longer range than elevators in middle-rise and high-rise buildings, ropes for elevators in very high buildings are required to have high safety factors, high modulus of elasticity, and low elongation. In addition, since elevators in very high buildings are operated at high speed within a long range, ropes for elevators in very high buildings are required to vibrate less so that passengers may feel comfortable during operation thereof or when the passengers get on/off the elevators.

One or more embodiments include an elevator wire rope in which fiber cores having a high grease content are arranged in an empty space between center strands and inner-layer strands or an empty space between the center strands so as to improve the flexibility of the wire rope while properties of the wire rope, such as high elasticity and low elongation, are maintained

According to one or more embodiments, a wire rope for an elevator includes: a rope core including center strands and fiber cores, each of the center strands being formed by twisting a plurality of wires; inner-layer strands arranged around the rope core, each of the inner-layer strands being formed by twisting a plurality of wires; and outer-layer strands arranged around the inner-layer strands, each of the outer-layer strands being formed by twisting a plurality of wires, wherein the inner-layer strands are ten in number, and the outer-layer strands are ten in number, wherein the fiber cores are arranged in at least one of an empty space between the center strands and the inner-layer strands and an empty space between the center strands.

The center strands may be three to five in number, and the fiber cores may be three to six in number. The fiber cores may be arranged in a center region of the rope core and the fiber cores are arranged within a first imaginary circle tangent to the center strands.

The wire rope may have a grease content of about 1.5% to about 2.5%. The fiber cores may include one of sisal, polypropylene (PP), polyethylene (PE), ultra-high-molecular polyethylene (UHMPE), and an aramid fiber.

Each of the center strands may include nine to nineteen wires. Each of the inner-layer strands may include seven to nine wires. Each of the outer-layer strands may include nineteen to twenty six wires.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

According to the one or more of the above embodiments, the fiber cores 112 having a relatively high grease content are arranged in an empty space between the center strands 111 and the inner-layer strands 120 or an empty space between the center strands 111 in the wire ropes 100 of the embodiments. Therefore, owing to the relative high grease content, the wire ropes 100 may have high flexibility and long fatigue life while the mechanical characteristics of wire ropes having steel cores (for example, mechanical characteristics of CFRC wire ropes), such as high elasticity and low elongation, are maintained.

In addition, according to the embodiments, the grease content of the fiber cores 112 arranged in an empty space between the center strands 111 and the inner-layer strands 120 or an empty space between the center strands 111 is adjustable, and thus, the grease content of the wire ropes 100 may be easily adjusted and managed according to environments in which the wire ropes 100 are used.

In addition, according to the embodiments, the fiber cores 112 may be arranged in center regions of the rope cores 110 of the wire ropes 100, and thus, the grease may be gradually supplied outward. Therefore, the grease may not scatter from the wire ropes 100 even when the wire ropes 100 are used under high-speed conditions. Therefore, the wire ropes 100 of the embodiments may have high quality and may be used in elevators for very high buildings.

These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a view illustrating a wire rope of the related art.

FIG. 2 is a cross-sectional view illustrating a wire rope product of the related art having a structure of 10x26WS + 10x7 + 1x36WS.

FIG. 3 is a cross-sectional view illustrating a wire rope having a structure of 10x19S + 10x7 + (3x9W +3F) in which a rope core includes three center strands and three fiber cores according to an embodiment.

FIG. 4 is a cross-sectional view illustrating a wire rope having a structure of 10x19S + 10x7 + (3x12W +3F) in which a rope core includes three center strands and three fiber cores according to an embodiment.

FIG. 5 is a cross-sectional view illustrating a wire rope having a structure of 10x19S + 10x7 + (3x15S +3F) in which a rope core includes three center strands and three fiber cores according to an embodiment.

FIG. 6 is a cross-sectional view illustrating a wire rope having a structure of 10x19S + 10x7 + (4x9W +4F) + 1FC in which a rope core includes four center strands and five fiber cores according to an embodiment.

FIG. 7 is a cross-sectional view illustrating a wire rope having a structure of 10x19S + 10x7 + (5x9W +5F) + 1FC in which a rope core includes five center strands and six fiber cores according to an embodiment.

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

One or more embodiments provide wire ropes for elevators. In the wire ropes, fiber cores having a high grease content are arranged in an empty space between center strands and inner-layer strands or an empty space between the center strands so as to improve the flexibility of the wire ropes while maintaining properties of the wire ropes such as high elasticity and low elongation. Hereinafter, the embodiments will be described with reference to the accompanying drawings.

Referring to FIG. 3, according to an embodiment, a wire rope 100 includes a rope core 110 including center strands 111 and fiber cores 112, inner-layer strands 120, and outer-layer strands 130.

The rope core 110 includes by the center strands 111 and the fiber cores 112. Each of the center strands 111 is formed by twisting a plurality of wires 1. For example, each of the center strands 111 may be formed by twisting nine to nineteen wires 1. The center strands 111 may have a Warrington (W) structure having no core such as 9W, 12W, or 19W.

However, the structure of the center strands 111 is not limited thereto. For example, the center strands 111 may have a Seale (S) structure. For example, the center strands 111 may have a 15S, 17S, or 19S structure. Warrington and Seale structures are well known in the related art, and thus, descriptions thereof will not be presented here.

The fiber cores 112 may have a grease content of about 10% to about 35%. Grease in the fiber cores 112 is supplied to the inner-layer strands 120 and the outer-layer strands 130. The supply of grease increases the flexibility of the wire rope 100 and prevents a decrease in the fatigue life of the wire rope 100. In addition, owing to the supply of grease, the wire rope 100 may not rust even though a plating layer of the wire rope 100 is damaged.

The fiber cores 112 may include a natural fiber such as sisal. However, the fiber cores 112 are not limited thereto. That is, the fiber cores 112 may include another kind of fiber. For example, the fiber cores 112 may include a synthetic fiber selected from polypropylene (PP), polyethylene (PE), ultra-high-molecular polyethylene (UHMPE), and an aramid fiber. For example, if the fiber cores 112 include UHMPE or an aramid fiber, the fracture strength of the wire rope 100 may increase, and thus, the fatigue life of the wire rope 100 may also increase. For example, the fiber cores 112 may include an aramid fiber such as Kelvar, Technora, Tawaron, or Heracron.

The rope core 110 includes the center strands 111 and the fiber cores 112. In this case, the number of the center strands 111 may be three to five, and the number of the fiber cores 112 may be three to six, thereby efficiently using an empty space of the rope core 110.

Each of the inner-layer strands 120 is formed by twisting a plurality of wires 1. For example, each of the inner-layer strands 120 may be formed by twisting seven to nine wires 1. The inner-layer strands 120 may include seven wires 1 having a 1+6 structure (in which six wires are twisted around a center wire). However, the inner-layer strands 120 may have a 9W structure. The structure of the inner-layer strands 120 is not limited to the above-mentioned structures but may be variously selected according to situations or required properties.

Each of the outer-layer strands 130 is formed by twisting a plurality of wires 1. For example, each of the outer-layer strands 130 may be formed by twisting nineteen to twenty six wires 1. If the diameter of the wire rope 100 is 12 mm or less, the outer-layer strands 130 may have a 19S structure, and if the diameter of the wire rope 100 is 12 mm or greater, the outer-layer strands 130 may have a 25Fi or 26 WS structure (25Fi refers to a filler structure, 26WS refers to a Warrington Seale structure, and since the filler structure and the Warrington Seale structure are well known in the related, detailed descriptions thereof will not be prevented here). The structure of the outer-layer strands 130 is not limited to the above-mentioned structures but may be variously selected according to situations or required properties.

The inner-layer strands 120 are arranged around the rope core 110, and the number of the inner-layer strands 120 is ten. The outer-layer strands 130 are arranged around the inner-layer strands 120, and the number of the outer-layer strands 130 is ten. That is, the rope core 110, the inner-layer strands 120, and the outer-layer strands 130 are sequentially arranged.

In the structure in which the inner-layer strands 120 are arranged around the rope core 110, an empty space is formed between the center strands 111 and the inner-layer strands 120. In addition, since the number of the center strands 111 of the rope core 110 is three to five, an empty space is formed between the center strands 111. The fiber cores 112 are arranged in the empty spaces.

Referring to FIGS. 3 to 7, the fiber cores 112 may be arranged in a center region of the rope core 110 within a first imaginary circle 140 tangent to the center strands 111. When the number of the center strands 111 is four or more, the fiber cores 112 may be arranged in a center region of the rope core 110, and in this case, the fiber cores 112 may be arranged in a central empty space among the center strands 111. As described above, the fiber cores 112 may be arranged within the first imaginary circle 140. However, the arrangement of the fiber cores 112 is not limited thereto.

For example, if there is an empty space between the center strands 111 and the inner-layer strands 120, the fiber cores 112 may be arranged outside the first imaginary circle 140. The fiber cores 112 may be compressed so as to be arranged between the center strands 111 and the inner-layer strands 120.

A center fit rope core (CFRC) type wire rope product 200 of the related art shown in FIG. 2 includes ten 26WS outer-layer strands, ten 7-wire inner strands, and a 36WS center strand. The wire rope 100 of the embodiment is provided based on the wire rope product 200 of the related art by replacing the 36WS center strand with the rope core 110 including three to five center strands 111 and the fiber cores 112 impregnated with grease.

The structure of the wire rope 100 of the embodiment may be expressed as follows:

Wire rope of embodiment: 10 x 26WS ＋ [10 x A ＋ (N x B + N x F) + FC]

wherein N is an integer ranging from 3 to 5, A refers to strands each including seven to nine wires, B refers to strands each including nine to nineteen wires, and F refers to fiber cores.

That is, A refers to the inner-layer strands 120, B refers to the center strands 111, and F refers to fiber cores 112. 10 x 26WS refers to the outer-layer strands 130. In the wire rope expression of the embodiment, FC refers to a fiber core 112 located at the center of the rope core 110, and F refers to fiber cores 112 located between the center strands 111 and the inner-layer strands 120.

The wire rope 100 of the embodiment may have a CFRC structure formed by simultaneously twisting center strands, inner-layer strands, and outer-layer strands. That is, a CFRC wire rope may be manufactured by arranging inner-layer strands around center strands, arranging outer-layer strands between outer sides of the inner-layer strands, and simultaneously twisting the strands.

The wire rope 100 of the embodiment may be manufactured through a twisting process as follows. After impregnating fiber cores 112 with grease, a rope core 110 is formed by arranging the fiber cores 112 in an empty space of the rope core 110. Then, ten inner-layer strands 120 and ten outer-layer strands 130 are simultaneously arranged and twisted around the rope core 110. In this manner, the wire rope 100 may be manufactured.

The wire rope 100 may have a grease content of about 1.5% to about 2.5%. The grease content of the fiber cores 112 of the wire rope 100 is adjustable, and thus, the grease content of the wire rope 100 may be adjusted by adjusting the grease content of the fiber cores 112 according to environments or conditions under which the wire rope 100 is used. In this manner, the grease content of the wire rope 100 may be maintained within the range of about 1.5% to about 2.5%. If the grease content of the wire rope 100 is too low (for example, less than about 1.5%), the flexibility or fatigue life of the wire rope 100 may decrease, or the wire rope 100 may rust. If the grease content of the wire rope 100 is too high (for example, greater than about 2.5%), grease may leak and scatter. Therefore, the grease content of the wire rope 100 may be adjusted to be within the range of about 1.5% to about 2.5% by using the fiber cores 112.

Wire ropes 100 will now be described according to embodiments. The following embodiments are for illustrative purposes only and are not intended to limit the scope of the inventive concept.

FIG. 2 illustrates the wire rope product 200 of the related art having a structure of 10x26WS + 10x7 + 1x36WS. FIGS. 3 to 5 illustrate wire ropes 100 in which a rope core 110 includes three center strands 111 and three fiber cores 112. That is, the wire rope 100 shown in FIG. 3 has a structure of 10x19S + 10x7 + (3x9W +3F), the wire rope 100 shown in FIG. 4 has a structure of 10x19S + 10x7 + (3x12W +3F), and the wire rope 100 shown in FIG. 5 has a structure of 10x19S + 10x7 + (3x15S +3F). FIG. 6 illustrates a rope core 110 incuding four center strands 111 and five fiber cores 112. That is, the wire rope 100 shown in FIG. 6 has a structure of 10x19S + 10x7 + (4x9W +4F) + 1FC. FIG. 7 illustrates a wire rope 100 in which a rope core 110 includes five center strands 111 and six fiber cores 112. That is, the wire rope 100 shown in 7 is 10x19S + 10x7 + (5x9W +5F) + 1FC.

The wire ropes 100 of the embodiments were compared with the wire rope product 200 of the related art (refer to FIG. 2) to evaluate the contents of grease and flexibility of the wire ropes 100, and comparison results are shown in Table 1 below. In Table 1, the content of grease in a wire rope and the content of grease in a rope core were measured by a weight method by measuring the weight of the wire rope and the weight of the rope core before and after removing grease.

No.	Rope structure	Grease content (%)
No.	Rope structure	Rope (%)	Increase (times)	Rope core (%)	Increase (times)
Product of the related art	10x26WS + 10x7 + 1x36WS	1.0 - 1.2	-	1.0 - 1.2	-
FIG. 3	10x19S + 10x7 + 3x9W +3F	1.2 - 1.6	1.0 - 1.3	3.0 - 6.0	2.5 - 5.0
FIG. 6	10x19S + 10x7 + 4x9W +4F + 1FC	1.4 - 2.0	1.2 - 1.7	4.0 - 8.0	3.3 - 6.7
FIG. 7	10x19S + 10x7 + 5x9W +5F + 1FC	1.5 - 2.5	1.3 - 2.1	5.0 - 11.0	4.2 - 9.2

In Table 1, test results obtained when the grease content of the fiber cores 112 was 15% are indicated first followed by test results obtained when the grease content of the fiber cores 112 was 30%. For example, in the case of the wire rope 100 shown in FIG. 7, when the grease content of the fiber cores 112 was 15%, the grease content of the wire rope 100 was 1.3 times the grease content of the wire rope product 200 of the related art, and when the grease content of the fiber cores 112 was 30%, the grease content of the wire rope 100 was 2.1 times the grease content of the wire rope product 200 of the related art.

Referring to Table 1, the grease content of the wire rope 100 shown in FIG. 7 (five center strands 111 and six fiber cores 112) is 1.3 times to 2.1 times the grease content of the wire rope product 200 of the related art. As described above, the grease content of the wire ropes 100 of the embodiments is greater than the grease content of the wire rope product 200 of the related art, and the grease content of the rope cores 110 of the embodiments also increased.

The wire ropes 100 of the embodiments have the following effects.

Wire ropes of the related art having steel cores have a relatively low grease content compared to wire ropes having fiber cores. Thus, these wire ropes have low flexibility and short fatigue life and may rust.

However, in the wire ropes 100 of the embodiments, the fiber cores 112 having a relatively high grease content are arranged in an empty space between the center strands 111 and the inner-layer strands 120 or an empty space between the center strands 111. Therefore, owing to the relatively high grease content, the wire ropes 100 may have high flexibility and long fatigue life while the mechanical characteristics of wire ropes having steel cores (for example, the mechanical characteristics of CFRC wire ropes) such as high elasticity and low elongation are maintained.

In addition, since the rope cores 110 of the wire ropes 100 of the embodiments are formed by the center strands 111 and the fiber cores 112, the flexibility of the rope cores 110 may be improved. In addition, since the fiber cores 112 impregnated with grease are arranged in an empty space between the center strands 111 and the inner-layer strands 120, the grease may be supplied to the inner-layer strands 120 and the outer-layer strands 130, and thus, the flexibility of the wire ropes 100 may be improved.

Since the flexibility of the wire ropes 100 is improved, when the wire ropes 100 are used under dynamic conditions and subjected to various loads, the amount of a bending stress in the wire ropes 100 may be relatively small, and thus, an elevator system using the wire ropes 100 may be operated with relatively low traction power.

In addition, the fiber cores 112 may be arranged in innermost center regions of the rope cores 110 so as to gradually distribute the grease while preventing scattering or too quick consumption of grease. Thus, grease may not be refilled, or refilling of grease may be delayed. In addition, fatigue characteristics of the wire ropes 100 may be improved. Thus, even when the wire ropes 100 are used under high-speed conditions, scattering of grease may be prevented. Therefore, the wire ropes 100 of the embodiments may have high quality and may be used in elevators for very high buildings.

In addition, since the grease content of the fiber cores 112 is adjustable, the grease content of the wire ropes 100 is also adjustable. That is, the grease content of the wire ropes 100 may be easily adjusted and managed according to environments in which the wire ropes 100 are used.

It should be understood that the embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments.

While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the inventive concept as defined by the following claims.

Claims

A wire rope for an elevator, the wire rope comprising:

a rope core comprising center strands and fiber cores, each of the center strands being formed by twisting a plurality of wires;

inner-layer strands arranged around the rope core, each of the inner-layer strands being formed by twisting a plurality of wires; and

outer-layer strands arranged around the inner-layer strands, each of the outer-layer strands being formed by twisting a plurality of wires,

wherein the inner-layer strands are ten in number, and the outer-layer strands are ten in number,

wherein the fiber cores are arranged in at least one of an empty space between the center strands and the inner-layer strands and an empty space between the center strands.
The wire rope of claim 1, wherein the center strands are three to five in number, and the fiber cores are three to six in number.
The wire rope of claim 1, wherein the fiber cores are arranged in a center region of the rope core and the fiber cores are arranged within a first imaginary circle tangent to the center strands.
The wire rope of claim 1, wherein the wire rope has a grease content of about 1.5% to about 2.5%.
The wire rope of claim 1, wherein the fiber cores comprise one of sisal, polypropylene (PP), polyethylene (PE), ultra-high-molecular polyethylene (UHMPE), and an aramid fiber.
The wire rope of claim 1, wherein each of the center strands comprises nine to nineteen wires.
The wire rope of claim 1, wherein each of the inner-layer strands comprises seven to nine wires.
The wire rope of claim 1, wherein each of the outer-layer strands comprises nineteen to twenty six wires.