EP2511219A1

EP2511219A1 - Rope for elevator

Info

Publication number: EP2511219A1
Application number: EP09852045A
Authority: EP
Inventors: Atsushi Mitsui; Atsushi Funada
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2009-12-08
Filing date: 2009-12-08
Publication date: 2012-10-17
Also published as: JPWO2011070648A1; WO2011070648A1; CN102639424A; KR20120070606A

Abstract

An elevator rope has a core rope, a plurality of outer layer strands, and a resin outer layer coating body. The core rope includes: a single steel core strand; a resin core strand coating body that is coated onto an outer circumference of the core strand; a core rope strand assembly that is constituted by a plurality of steel core rope strands that are disposed on an outer circumference of the core strand coating body; and a resin core rope coating body that is disposed on an outer circumference of the core rope strand assembly. A resin outer layer coating body is fixed adhesively to the outer layer strands. The core strand and the core rope strands have a three-layer construction in which two layers of wires are bound onto an outer circumference of a central wire. The outer layer strands have a two-layer construction in which a single layer of wires is bound onto an outer circumference of a central wire.

Description

TECHNICAL FIELD

The present invention relates to an elevator rope in which a plurality of steel strands and a plurality of resin coating bodies are combined.

BACKGROUND ART

In conventional elevator ropes, a plurality of inner layer strands are disposed outside a core rope that is formed by twisting together a plurality of core strands, and a plurality of outer layer strands are disposed outside the inner layer strands. A resin core rope coating body is disposed between the core rope and the inner layer strands, a resin inner layer coating body is disposed between the inner layer strands and the outer layer strands, and a resin outer layer coating body is disposed outside the outer layer strands (see Patent Literature 1, for example).

CITATION LIST

PATENT LITERATURE

[Patent Literature 1]
Japanese Patent No. 4108607 (Gazette )

SUMMARY OF THE INVENTION

PROBLEM TO BE SOLVED BY THE INVENTION

In conventional elevator ropes such as that described above, since a core rope that is formed by twisting together core strands is disposed centrally, a process is required for twisting the core strands together, making manufacturing time-consuming. A cross-sectional shape of a core rope that is formed by twisting strands together is comparatively susceptible to collapsing under external forces, and since forces are concentrated at rope centers when wound around sheaves, there is a risk that the cross-sectional shape of the core rope may collapse, and the cross-sectional shape of the entire elevator rope may also collapse.
The present invention aims to solve the above problems and an object of the present invention is to provide an elevator rope that can facilitate manufacturing, and that can also make cross-sectional shape less prone to be deformed.

MEANS FOR SOLVING THE PROBLEM

In order to achieve the above object, according to one aspect of the present invention, there is provided an elevator rope including: a core rope including: a single steel core strand; a resin core strand coating body that is coated onto an outer circumference of the core strand; a core rope strand assembly that is constituted by a plurality of steel core rope strands that are disposed on an outer circumference of the core strand coating body; and a resin core rope coating body that is disposed on an outer circumference of the core rope strand assembly; an outer layer strand assembly that is constituted by a plurality of steel outer layer strands that are disposed on an outer circumference of the core rope coating body; and a resin outer layer coating body that is disposed on an outer circumference of the outer layer strand assembly, wherein: the core strand and the core rope strands have a three-layer construction in which two layers of wires are bound onto an outer circumference of a central wire; and the outer layer strands have a two-layer construction in which a single layer of wires is bound onto an outer circumference of a central wire.

EFFECTS OF THE INVENTION

Since the elevator rope according to the present invention uses only a single core strand 1, steps for twisting the strands together can be reduced, enabling manufacturing to be facilitated. Since the core rope strands 3 are disposed on the outer circumference of the core strand coating body without being twisted directly onto the outer circumference of the core strand, the cross-sectional shape of the core rope can be made less prone to deform.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a cross section of an elevator rope according to Embodiment 1 of the present invention;
Figure 2 is a cross section of an elevator rope according to Embodiment 2 of the present invention;
Figure 3 is a cross section of an elevator rope according to Embodiment 3 of the present invention;
Figure 4 is a cross section of an elevator rope according to Embodiment 4 of the present invention; and
Figure 5 is a side elevation that shows an example of an elevator apparatus to which the elevator rope of Embodiments 1, 2, 3, or 4 is applied.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the present invention will now be explained with reference to the drawings.

Embodiment 1

Figure 1 is a cross section of an elevator rope according to Embodiment 1 of the present invention. In the figure, a single steel core strand 1 is disposed centrally in an elevator rope. A resin core strand coating body 2 is disposed on an outer circumference of the core strand 1. A plurality of (in this case, eight) steel core rope strands 3 are twisted together on an outer circumference of the core strand coating body 2.
A resin core rope coating body 5 is disposed on an outer circumference of a core rope strand assembly 4 that is constituted by the eight core rope strands 3 and the core strand coating body 2. A core rope 6 is constituted by the core strand 1, the core strand coating body 2, the core rope strands 3, and the core rope coating body 5.
A plurality of (in this case, twenty) steel outer layer strands 7 are twisted together on the outer circumference of the core rope coating body 5. A resin outer layer coating body 9 is disposed on the outer circumference of an outer layer strand assembly 8 that is constituted by the twenty outer layer strands 7 and the core rope coating body 5. The outer layer strands 7 and the outer layer coating body 9 are fixed using an adhesive.
All of the strands, including the core strand 1, the core rope strands 3, and the outer layer strands 7, are compressed (plastic working) from an outer circumference by a die during manufacturing to modify cross-sectional shapes of wires therein.
The core strand 1 and the core rope strands 3 have three-layer constructions in which two layers of wires are bound on an outer circumference of a central wire. The cross-sectional constructions of the core strand 1 and the core rope strands 3 are Seale. In addition, the lay lengths of the two layers of wires in the core strand 1 and the core rope strands 3 are equal. In other words, the core strand 1 and the core rope strands 3 are constituted by parallel lays. The outer layer strands 7 have a two-layer construction in which a single layer of wires is bound on an outer circumference of a central wire.
Resins that have a certain amount of hardness such as polyethylene or polypropylene, for example, are used as the materials for the core strand coating body 2 and the core rope coating body 5 since it is necessary to bear the pressure from the core rope strands 3 and the outer layer strands 7. The core strand coating body 2 and the core rope coating body 5 are constituted by resins that are cross-linked by introducing a cross-linking agent.
In addition, the coefficients of friction of the core strand coating body 2 and the core rope coating body 5 should be reasonably low in order to increase flexibility of the elevator rope and also to reduce loss that occurs during flexing by the sheaves.
Thus, it is preferable for the materials of the core strand coating body 2 and the core rope coating body 5 to be harder than the material of the outer layer coating body 9 and to have lower coefficients of friction relative to identical metal materials. In addition, it is preferable for the core strand coating body 2 and the core rope coating body 5 to have superior wear resistance since slippage arises against the core strand 1, the core rope strands 3, and the outer layer strands 7.
Since it is necessary to ensure traction capacity on the sheaves, the outer layer coating body 9 is constituted by a resin that has sufficient wear resistance at a coefficient of friction on the sheaves that is greater than or equal to 0.2, such as a polyurethane, for example. The outer layer strands 7 are constituted by a resin that is cross-linked by introducing a cross-linking agent.
It is preferable for the core strand coating body 2 and the core rope coating body 5 to enter between the adjacent core rope strands 3 and be in contact with each other as shown in Figure 1 even when subjected to tension during use. It is also preferable for the core rope coating body 5 and the outer layer coating body 9 to enter between the adjacent outer layer strands 7 and be in contact with each other as shown in Figure 1 even when subjected to tension during use.
In an elevator rope of this kind, since only one core strand 1 is used, deformation is less likely to occur when tension acts during use and a load is applied to the core strand 1 from the core rope strands 3, enabling the cross-sectional shape of the entire elevator rope to be stabilized, and steps for twisting the strands together can be reduced, enabling manufacturing to be facilitated. Since the core rope strands 3 are also twisted onto the outer circumference of the core strand coating body 2 without being twisted directly onto the outer circumference of the core strand 1, the cross-sectional shape of the core rope 6 can be made less prone to deform, thereby also enabling the cross-sectional shape of the entire elevator rope to be stabilized.
In addition, since none of the strands, including the core strand 1, the core rope strands 3, and the outer layer strands 7, contact other strands directly, abrasive wear due to contact among the strands is prevented, enabling extension of the service life of the elevator rope.
Furthermore, in order to generate traction on the sheaves, it is necessary to fix the outer layer coating body 9 to the outer layer strands 7 adhesively, and it is necessary to wash away extraneous contamination or oil satisfactorily during manufacturing of the outer layer strands 7 before fixing the outer layer coating body 9 to the outer layer strands 7 adhesively. Here, satisfactory washing into interior portions of the outer layer strands 7 is not possible if the construction of the outer layer strands 7 is complicated. In answer to that, because the core strand 1 and the core rope strands 3 have three-layer constructions and the outer layer strands 7 have two-layer constructions in Embodiment 1, sufficient strength is ensured and the outer layer strands 7 are also sufficiently and easily washed, enabling the outer layer coating body 9 to be fixed firmly to the outer layer strands 7 adhesively.
Because the cross-sectional shapes of the wires of the core strand 1, the core rope strands 3, and the outer layer strands 7 are modified, effective cross-sectional area can be increased compared to strands to which diameter shaping has not been applied.
In addition, because the core strand coating body 2 and the core rope coating body 5 are constituted by cross-linked resin materials, durability is increased against temperature increases due to use in high-temperature environments or due to the continuous action of flexing, etc., enabling service life to be extended.
Furthermore, because the outer layer coating body 9 is also constituted by a cross-linked resin material, durability is increased against temperature increases due to use in high-temperature environments or due to the continuous action of flexing, etc., enabling service life to be extended. Deterioration in strength from temperature increases due to slippage between the sheaves and the elevator rope during emergency braking can also be prevented, enabling sufficient deceleration performance to be maintained.
Since the cross-sectional constructions of the core strand 1 and the core rope strands 3 are Seale, and the wires of the core strand 1 and the core rope strands 3 are twisted together parallel to each other, the wires are in line contact with each other, enabling abrasive wear in the core strand 1 and the core rope strands 3 to be reduced, and air gaps between the wires are reduced, enabling the effective cross-sectional area to be increased.
Now, if the number of the outer layer strands 7 is increased, service life against flexural fatigue can be lengthened if an identical cross-sectional construction is used, since the diameters of the wires that constitute the outer layer strands 7 can be made slender. However, it then becomes necessary to stratify the cross-sectional construction of the core rope 6 or stratify the strands that are contained in the core rope 6 in order to ensure required flexibility (resistance to flexural fatigue) by an amount proportionate to the increase in cross-sectional area ratio of the core rope 6, making the configuration complicated, and the number of wires and strands is also increased, making manufacturing time-consuming, and increasing manufacturing costs.
If the number of outer layer strands 7 is reduced, on the other hand, local surface pressure from the outer layer strands 7 that acts on the outer layer coating body 9 when the sheave grooves and the elevator rope contact each other increases, making it more likely that the outer layer strands 7 will be damaged. It is also necessary to stratify the cross-sectional construction of the outer layer strands 7 further in order to ensure required flexibility, making the configuration complicated and also reducing the packing density, i.e., reducing the effective cross-sectional area, of the entire elevator rope.
If similar attempts are also made to ensure the effective cross-sectional area, i.e., the rope diameter, by making the diameters of the wires equal, it becomes necessary to increase the number of wires, and to increase the layers of wires.
As a practical answer thereto, by making the number of outer layer strands 7 two to 2.5 times the number of strands (the core strand 1 and the core rope strands 3) that are contained in the core rope 6, flexibility can be made superior to conventional elevator ropes, pressure from the outer layer strands 7 that acts on the outer layer coating body 9 can be suppressed during contact with the sheave grooves, and manufacturing costs can be suppressed.

Embodiment 2

Next, Figure 2 is a cross section of an elevator rope according to Embodiment 2 of the present invention. Shaping was applied to all of the strands in Embodiment 1, but shaping is not applied to the core strand 1 in Embodiment 2. The rest of the configuration is similar or identical to that of Embodiment 1.
Now, if wire breakage occurs in some of the wires in the core strand 1 due to nonuniformity in wire tension during manufacturing, for example, phenomena such as the broken wires protruding from the outer circumference of the core strand 1 arise easily since the core strand 1 exists separately at the center, is not twisted with other strands, and the forces constraining the broken wires are weak. Because the core strand 1 is configured by combining wires that have different diameters, wires that have smaller diameters are preferentially prone to break due to pressure that acts from outside. Thus, if some of the wires of the core strand 1 break, giving rise to a collapse in the cross-sectional shapes of the core strand 1, there is a risk that the cross-sectional shape of the entire elevator rope may also collapse.
In answer thereto, in Embodiment 2, by exclusively not applying shaping to the core strand 1, if wire breakage occurs in the wires of the core strand 1, deformation of the broken wires is absorbed within a range of gaps inside the core strand 1, enabling collapse of the cross-sectional shape of the core strand 1 to be suppressed. Making wire tension uniform during manufacturing can be facilitated compared to when shaping is applied, enabling early breakage of the wires to be suppressed.

Embodiment 3

Next, Figure 3 is a cross section of an elevator rope according to Embodiment 3 of the present invention. In Embodiment 3, the number of core rope strands 3 is set to six. Consequently, the number of outer layer strands 7 is set to sixteen. The rest of the basic cross-sectional construction is similar or identical to that of Embodiment 1.
By setting the number of the core rope strands 3 to six in this manner, the diameters of all of the strands (the core strand 1 and the core rope strands 3) that are contained in the core rope 6 can be made practically identical, enabling the diameters of the wires that constitute the strands thereof also to be made practically identical.
Now, in types of conventional elevator ropes in which resin coatings are not used, wire breakage is generated primarily in portions that contact the sheaves, and wire breakage develops from those portions. In contrast to that, in an elevator rope that has an outer layer coating body 9, since the outer layer strands 7 do not contact the sheaves, and the strands do not contact each other either, flexural stresses that arise in wires due to being flexed at the sheaves are dominant as factors that determine fatigue life.
In the elevator rope according to Embodiment 3, since the diameters of the wires that constitute the core strand 1 and the core rope strands 3 are practically identical, damage can be prevented from developing early in specific parts due to flexural stresses, enabling the service life of the entire elevator rope to be extended. To achieve effects of this kind more reliably, it is preferable for differences between the diameter of the thickest wire in the core strand 1, the diameters of the thickest wires in the core rope strands 3, and the diameters of the thickest wires in the outer layer strands 7 to be practically eliminated, specifically to less than 0.1 mm.
By practically eliminating differences between the diameters of all of the strands, including the core strand 1, the core rope strands 3, and the outer layer strands 7, together with the diameters of the wires, specifically to less than 1 mm, flexibility of the elevator rope can be improved, also enabling manufacturing equipment to be unified.
In Embodiment 3 in particular, the outer layer strands 7 are constituted by 16 x 7 (sixteen outer layer strands 7 that are each constituted by seven wires), and the core rope 6 is constituted by 6 x S(19) +S(19) (six core rope strands 3 in which nineteen wires are disposed in Seale form, and a single core strand 1 in which nineteen wires are disposed in Seale form).
The maximum diameters of the wires of the core strand 1, the core rope strands 3 and the outer layer strands 7 can thereby be made approximately equal while keeping the number of wires in the entire elevator rope down to 245. As a result, fatigue resistance is increased, packing density, i.e., effective cross-sectional area can be improved, and manufacturing costs can be suppressed. Thus, it is preferable for the total number of all of the wires that are contained in all of the strands, including the core strand 1, the core rope strands 3, and the outer layer strands 7, to be set to less than or equal to 250.
By configuring as described above, the rope diameter excluding the outer layer coating body 9 can be set to 8 mm, and the diameters of all of the wires can be set to less than or equal to 0.5 mm. Thus, the diameters of the sheaves can be set to a minimum of 200 mm, or greater than or equal to 400 times the diameters of the wires, enabling sufficient flexural fatigue service life to be ensured.
In addition, since the packing density of the elevator rope according to Embodiment 3 is high, and wire strength is also high, a rope diameter of 8 mm corresponds to a rope diameter of 10 mm in a type of elevator rope that does not use any resin coating at all. Since the minimum diameter of the sheaves is 400 mm when the rope diameter is set to 10 mm, the diameters of the sheaves can be halved.

Embodiment 4

Next, Figure 4 is a cross section of an elevator rope according to Embodiment 4 of the present invention. Shaping is not applied to the core strand 1 in Embodiment 4. The rest of the configuration is similar or identical to that of Embodiment 3.
Using this kind of construction, collapsing of the cross-sectional shape of the core strand 1 can be suppressed, and early breakage of the wires can be suppressed in a similar manner to Embodiment 2.
Now, Figure 5 is a side elevation that shows an example of an elevator apparatus to which the elevator rope of Embodiments 1, 2, 3, or 4 is applied. In the figure, a machine room 12 is disposed in an upper portion of a hoistway 11. A machine base 13 is installed inside the machine room 12. A hoisting machine 14 is supported on the machine base 13. The hoisting machine 14 has a driving sheave 15 and a hoisting machine main body 16. The hoisting machine main body 16 has: a hoisting machine motor that rotates the driving sheave 15; and a hoisting machine brake that brakes the rotation of the driving sheave 15.
A deflecting sheave 17 is mounted to the machine base 13. A plurality of elevator ropes 18 that function as a suspending means are wound around the driving sheave 15 and the deflecting sheave 17. Portions of the elevator ropes 18 that are nearer to the counterweight 10 than the driving sheave 15 are wound around the deflecting sheave 17.
A car 19 is suspended on first end portions of the elevator ropes 18. Specifically, the car 19 is suspended inside the hoistway 11 by the elevator ropes 18 on a first side of the driving sheave 15. A counterweight 20 is suspended on second end portions of the elevator ropes 18. Specifically, the counterweight 20 is suspended by the elevator ropes 18 on a second side of the driving sheave 15.
A pair of car guide rails 21 that guide raising and lowering of the car 19 and a pair of counterweight guide rails 22 that guide raising and lowering of the counterweight 20 are installed inside the hoistway 11. Emergency stopper apparatuses 23 that make the car 19 perform an emergency stop by engaging with the car guide rail 21 are mounted to the car 19.
Moreover, the type of elevator apparatus to which the elevator rope according to the present invention is applied is not limited to the type in Figure 5. For example, the present invention can also be applied to machine-roomless elevators, elevator apparatuses that use two-to-one (2:1) roping methods, multi-car elevators, or double-deck elevators.
The elevator rope according to the present invention can also be applied to ropes other than ropes for suspending a car 19, such as compensating ropes or governor ropes, for example.

Claims

An elevator rope comprising:
a core rope comprising:
a single steel core strand;

a resin core strand coating body that is coated onto an outer circumference of the core strand;

a core rope strand assembly that is constituted by a plurality of steel core rope strands that are disposed on an outer circumference of the core strand coating body; and

a resin core rope coating body that is disposed on an outer circumference of the core rope strand assembly;

an outer layer strand assembly that is constituted by a plurality of steel outer layer strands that are disposed on an outer circumference of the core rope coating body; and

a resin outer layer coating body that is disposed on an outer circumference of the outer layer strand assembly, and that is fixed adhesively to the outer layer strands, wherein:
the core strand and the core rope strands have a three-layer construction in which two layers of wires are bound onto an outer circumference of a central wire; and

the outer layer strands have a two-layer construction in which a single layer of wires is bound onto an outer circumference of a central wire.
An elevator rope according to Claim 1, wherein all of the strands including the core strand, the core rope strands, and the outer layer strands are compressed from an outer circumference during manufacturing to modify cross-sectional shapes of wires therein.
An elevator rope according to Claim 1, wherein among the strands including the core strand, the core rope strands, and the outer layer strands, all strands except for the core strand are compressed from an outer circumference during manufacturing to modify cross-sectional shapes of wires therein.
An elevator rope according to Claim 1, wherein a material of the core strand coating body and the core rope coating body is harder than a material of the outer layer coating body and has a lower coefficient of friction relative to an identical metal material.
An elevator rope according to Claim 1, wherein the core strand coating body and the core rope coating body are constituted by a cross-linked resin material.
An elevator rope according to Claim 1, wherein the outer layer coating body is constituted by a cross-linked resin material.
An elevator rope according to Claim 1, wherein a cross-sectional construction of the core strand and the core rope strands is Seale, and wires of the core strand and the core rope strands are laid parallel to each other.
An elevator rope according to Claim 1, wherein a difference in diameter among all of the strands including the core strand, the core rope strands, and the outer layer strands is less than 1 mm.
An elevator rope according to Claim 1, wherein a difference between a maximum diameter of wires of the core strand, a maximum diameter of wires of the core rope strands, and a maximum diameter of wires of the outer layer strands is less than 0.1 mm.
An elevator rope according to Claim 1, wherein a total number of all wires that are contained in all of the strands including the core strand, the core rope strands, and the outer layer strands is less than or equal to 250.