EP1582493B1

EP1582493B1 - Rope for elevator and elevator equipment

Info

Publication number: EP1582493B1
Application number: EP02775541A
Authority: EP
Inventors: Takenobu c/o Mitsubishi Denki Kabushiki K. HONDA
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2002-11-12
Filing date: 2002-11-12
Publication date: 2013-02-20
Anticipated expiration: 2022-11-12
Also published as: WO2004043844A1; CN1585721A; EP1582493A4; JP4296152B2; KR20040071180A; CN100439227C; EP1582493A1; JPWO2004043844A1

Description

TECHNICAL FIELD

The present invention relates to an elevator rope used in an elevator to suspend a car, and to an elevator apparatus using that rope.

BACKGROUND ART

Conventionally, in elevator apparatuses, sheaves having a diameter greater than or equal to forty (40) times a diameter of a rope are used in order to prevent early abrasion and wire breakage in the ropes. Consequently, in order to reduce the diameter of the sheaves, it is necessary to also reduce the diameter of the ropes.
However, if the rope diameter is reduced, there is a risk that a car may be easily vibrated by load fluctuations due to baggage loaded onto the car, or passengers getting on and off, etc., or that vibrations in the ropes at the sheaves may propagate to the car. Furthermore, the number of ropes must be increased, making the construction of the elevator apparatus complicated. In addition, if the diameter of the drive sheaves is reduced, drive friction decreases, making it necessary to add weight to the car.
JP 07-010 478 A discloses a thin and lightweight high strength wire rope having an ultrahigh strength appropriate for a material handling machine such as a crane with a resin coating layer.
JP 03-249288 A describes a wire rope for running wires, having a thin thermoplastic resin cushioning layer in a space between a core rope and side strands.

DISCLOSURE OF THE INVENTION

The present invention aims to solve the above problems and an object of the present invention is to provide an elevator rope enabling reductions in diameter while maintaining high strength, long service life, and high friction, and to provide an elevator apparatus having a compact layout using that rope.
In order to achieve the above object, according to one aspect of the present invention, there is provided an elevator rope including: an inner layer rope having a plurality of inner layer strands in which a plurality of steel wires are twisted together; an inner layer coating body made of resin coated onto an outer periphery of the inner layer rope; and an outer layer having a plurality of outer layer strands in which a plurality of steel wires are twisted together disposed on an outer peripheral portion of the inner layer coating body.
According to another aspect of the present invention, there is provided an elevator apparatus including: a driving machine having a drive sheave on which a rope groove is disposed; an elevator rope inserted into the rope groove and wound around the drive sheave; and a car and a counterweight suspended inside a hoistway by the elevator rope and raised and lowered by the driving machine, wherein: the elevator rope has an inner layer rope including a plurality of inner layer strands in which a plurality of steel wires are twisted together; an inner layer coating body made of resin coated onto an outer periphery of the inner layer rope; and an outer layer including a plurality of outer layer strands in which a plurality of steel wires are twisted together disposed on an outer peripheral portion of the inner layer coating body; and a surface of the rope groove contacting the elevator rope is composed of a high-friction resin material.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a general front elevation showing an elevator apparatus according to Embodiment 1 of the present invention;
Figure 2 is a plan showing the elevator apparatus in Figure 1;
Figure 3 is a cross section of an elevator rope from Figure 1;
Figure 4 is a side elevation showing the elevator rope in Figure 3 cut away in layers;
Figure 5 is a front elevation showing a sheave used as a drive sheave, a car suspension sheave, a counterweight suspension sheave, a car guide pulley, and a counterweight guide pulley in Figure 1;
Figure 6 is a cross section of a rope groove from Figure 5;
Figure 7 is a cross section of an elevator rope according to Embodiment 2 of the present invention; and
Figure 8 is a side elevation showing an elevator rope according to Embodiment 3 of the present invention cut away in layers.

BEST MODE FOR CARRYING OUT THE INVENTION

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

Embodiment 1

Figure 1 is a general front elevation showing an elevator apparatus according to Embodiment 1 of the present invention, and Figure 2 is a plan showing the elevator apparatus in Figure 1. In the figures, a supporting platform 32 is secured to an upper portion inside a hoistway 31. A thin driving machine 33 is mounted on the supporting platform 32. The driving machine 33 has: a motor 34; and a drive sheave 35 rotated by the motor 34. The driving machine 33 is disposed horizontally such that a rotating shaft of the drive sheave 35 extends vertically.
A plurality of elevator ropes 36 (only one is shown in the figures) are wound around the drive sheave 35. Each of the elevator ropes 36 has a first end portion 36a and a second end portion 36b connected to the supporting platform 32.
A car 37 is suspended between the first end portions 36a of the elevator ropes 36 and the drive sheave 35. A pair of car suspension sheaves 38 around which the elevator ropes 36 are wound are disposed on a lower portion of the car 37.
A counterweight 39 is suspended between the second end portions 36b of the elevator ropes 36 and the drive sheave 35. A pair of counterweight suspension sheaves 40 around which the elevator ropes 36 are wound are disposed on an upper portion of the counterweight 39. The car 37 and the counterweight 39 are raised and lowered inside the hoistway 31 by the driving machine 33 by means of the elevator ropes 36.
A car guide pulley 41 for directing the elevator ropes 36 extending from the drive sheave 35 toward the car 37 is disposed in an upper portion inside the hoistway 31. A counterweight guide pulley 42 for directing the elevator ropes 36 extending from the drive sheave 35 toward the counterweight 39 is also disposed in an upper portion inside the hoistway 31.
The driving machine 33, the car guide pulley 41, and the counterweight guide pulley 42 are disposed so as to overlap with the car 37 in a vertical plane of projection. Diameters of the car guide pulley 41 and the counterweight guide pulley 42 are greater than or equal to fifteen (15) times and less than or equal to twenty (20) times a diameter of the elevator ropes 36.
A pair of car guide rails 43 for guiding raising and lowering of the car 37 and a pair of counterweight guide rails 44 for guiding raising and lowering of the counterweight 39 are installed inside the hoistway 31. Moreover, the guide rails 43 and 44 are omitted from Figure 1.
Next, Figure 3 is a cross section of an elevator rope 36 from Figure 1, and Figure 4 is a side elevation showing the elevator rope 36 in Figure 3 cut away in layers.
In the figures, an inner layer rope 1 has: a core rope 2; and a plurality of inner layer strands 3 disposed on outer peripheral portions of the core rope 2. The core rope 2 has a plurality of core strands 4. Each of the core strands 4 is constructed by twisting a plurality of steel wires 5 together with each other. The core strands 4 are twisted together with each other, and the inner layer strands 3 are twisted in a reverse direction to the core strands 4.
The inner layer strands 3 are constructed by twisting a plurality of steel wires 6 together with each other. The cross-sectional structure of the inner layer strands 3 is warrington (Japanese Industrial Standards (JIS) G 3525). A diameter of the inner layer rope 1 is set to less than or equal to 1/27 of a diameter of the drive sheave 35.
An inner layer coating body 7 made of resin is coated onto an outer periphery of the inner layer rope 1. The inner layer coating body 7 is composed of polyethylene resin, for example.
An outer layer 8 is disposed on an outer peripheral portion of the inner layer coating body 7. The outer layer 8 has a plurality of outer layer strands 9. Each of the outer layer strands 9 is constituted by: a central wire 10 disposed centrally; and six outer peripheral wires 11 disposed on an outer periphery of the central wire 10. The outer layer strands 9 are twisted in a reverse direction to the inner layer strands 3.
Diameters of all of the wires 5, 6, 10, and 11 are set to less than or equal to 1/400 of the diameter of the drive sheave 35.
Next, Figure 5 is a front elevation showing a sheave used as a drive sheave 35, a car suspension sheave 38, a counterweight suspension sheave 40, a car guide pulley 41, and a counterweight guide pulley 42 in Figure 1, and Figure 6 is a cross section of a rope groove from Figure 5.
In the figures, rope grooves 45 into which the elevator ropes 36 are inserted are disposed on an outer peripheral portion of the sheave used as a drive sheave 35, a car suspension sheave 38, a counterweight suspension sheave 40, a car guide pulley 41, and a counterweight guide pulley 42. A surface of the rope grooves 45 contacting the elevator ropes 36 is constituted by a high-friction resin material (a resin lining) 46. A material having a coefficient of friction greater than or equal to 0.2, such as polyurethane resin, for example, is used as the material in the high-friction resin material 46.
In an elevator apparatus of this kind, since a steel inner layer rope 1 is disposed in a central portion of the elevator ropes 36, and outer layer strands 9 having a smaller diameter than inner layer strands 3 are disposed on an outer periphery of the inner layer rope 1, the packing density of the steel wires 5, 6, 10, and 11 can be increased, while suppressing the overall diameter, enabling increases in the strength of the elevator ropes 36.
Since an inner layer coating body 7 made of resin is disposed between the inner layer rope 1 and the outer layer 8, the inner layer strands 3 and the outer layer strands 9 are prevented from direct contacting and rubbing against each other, enabling deterioration due to abrasion to be prevented and bending stresses to be alleviated by a buffer action, thereby enabling extension of the service life of the elevator ropes 36.
In addition, since surfaces of the rope grooves 45 contacting the elevator ropes 36 are constituted by a high-friction resin material 46, the outer layer strands 9 can be prevented from being abraded by direct contact with the sheaves 35, 38, 40, 41, and 42. Furthermore, bending stresses arising due to the wires 10 and 11 of the outer layer strands 9 being crushed against the sheaves 35, 38, 40, 41, and 42 can also be alleviated, thereby enabling extension of the service life of the elevator ropes 36 and enabling reductions in the diameter of the sheaves 35, 38, 40, 41, and 42. Consequently, the overall strength of the elevator ropes 36 can be further increased, and the sheaves 35, 38, 40, 41, and 42 can be constructed inexpensively.
Furthermore, by disposing the high-friction resin material 46 in the rope grooves 45, sufficient transfer efficiency of the driving force can be ensured even if the diameter of the drive sheave 35 is reduced. Consequently, it is no longer necessary to add weight to the car in order to increase friction between the elevator ropes 36 and the drive sheave 35, or to add guide pulleys in order to increase the contact angle of the elevator ropes 36 on the drive sheave 35, etc. , preventing the construction of an elevator apparatus from becoming complicated.
Here, it is preferable for the high-friction resin material 46 to have a coefficient of friction greater than or equal to 0.2, enabling sufficient transfer efficiency of the driving force to be ensured. Furthermore, provided that the coefficient of friction is greater than or equal to 0.2, the high-friction resin material 46 is not limited to polyurethane, and polyvinyl, etc., can also be used.
Soft or hard polyurethane resin can also be selected freely, but in order to ensure abrasion resistance performance against phenomena such as the elevator ropes 36 slipping slightly on the surface of the sheaves 35, 38, 40, 41, and 42, it is preferable to use hard polyurethane resin having a hardness of 85 to 98. In particular, polyurethane resin having a hardness greater than or equal to 90 is most preferable. In order to prevent hydrolysis from occurring in the service environment, it is also desirable that the resin be ether-based rather than ester-based.
In addition, because the high-friction resin material 46 is disposed in the rope grooves 45, processing is facilitated compared to when an outermost circumference of the elevator ropes 36 is coated with a high-friction resin material.
Furthermore, flexing resistance can be reduced by selecting as the material for the inner layer coating body 7 a material that slides freely and easily when the elevator ropes 36 are bent at the sheaves 35, 38, 40, 41, and 42. Furthermore, the inner layer coating body 7 requires a hardness that can resist being crushed between the wires 6 of the inner layer strands 3 and between the wires 11 of the outer layer strands 9. A hard, low-friction polyethylene material is suitable as this kind of the material.
A resin such as nylon, silicon, polypropylene, or polyvinyl chloride, etc., for example, may also be used as the material for the inner layer coating body 7. By using an inner layer coating body 7 of this kind, reductions in the service life when a steel inner layer rope 1 is used can be suppressed.
In addition, since the outer layer strands 9 have a simple seven-wire construction including a central wire 10 and six outer peripheral wires 11, the diameter of the elevator ropes 36 can be reduced and disarray can be suppressed.
Furthermore, because the cross-sectional construction of the inner layer strands 3 is warrington, not seale or filler wire, breakage of the wires 6 due to wear can be prevented without using extremely slender wires 6, enabling extension of service life. In order to achieve extension of service life, it is preferable for the wires 6 of the inner layer strands 3 to be in parallel lay rather than cross lay. Here, by making the number of wires 6 positioned in the outer peripheral portions equal to or twice the number of wires 6 positioned inside them, the wires 6 can be disposed in a well-balanced manner without strain, enabling wear of the wires 6 to be further prevented.
In elevator ropes 36 having a multilayered construction, rotational torque in a direction in which twisting returns may occur in interior portions due to repetitive bending by the sheaves and tension due to loads over time, and there is a risk that the load burden balance of each of the layers may collapse, reducing breaking strength and service life.
In regard to this, by twisting the inner layer strands 3 in a reverse direction to the core strands 4, and twisting the outer layer strands 9 in a reverse direction to the inner layer strands 3, the rotational torque in the interior portions can be balanced, enabling the overall twisting return torque of the rope to be reduced.
If elevator ropes 36 having high flexibility as described above are wound around sheaves 35, 38, 40, 41, and 42 having a small diameter, there is a risk that contact pressure between the sheaves 35, 38, 40, 41, and 42 and the outer layer strands 9 may increase, considerably advancing wear and tear on the sheaves 35, 38, 40, 41, and 42 and the outer layer strands 9.
For this reason, if applied to sheaves having a diameter that is twenty (20) times the diameter of the elevator ropes 36, it is preferable to make the number of outer layer strands 9 greater than or equal to twelve (12) (there are nineteen (19) in Figure 3). Furthermore, if applied to sheaves having a diameter that is fifteen (15) times the diameter of the elevator ropes 36, it is preferable to make the number of outer layer strands 9 greater than or equal to sixteen (16).
Thus, increases in the contact pressure between the sheaves and the outer layer strands 9 can be suppressed, enabling wear and tear on the sheaves and the outer layer strands 9 to be suppressed. Consequently, it is no longer necessary for the sheaves to be made of a particularly expensive material, enabling the sheaves to be constructed inexpensively.
In addition, if the surface of the rope grooves is made of metal, service life is determined by the number of cycles of tension and bending stresses at the sheaves, and wire breakage occurs first in the wires at the rope surface. However, if the high-friction resin material 46 is disposed in the rope grooves 45, wires in interior portions, rather than at the surface of the rope, are preferentially more likely to break due to bending fatigue since contact pressure with the sheaves is reduced.
The number of service life cycles determined by bending fatigue of this kind, according to the experimental research by the inventors, was found to have a relationship represented by the following expressions:

Service life formulas
Formula for breakage of wires contacting sheaves: $Number of service life cycles Nc = 10.0 x k x {1.05}^{D / d}$
Formula for breakage of wires inside rope: $Number of service life cycles Nn = 19.1 x k x {1.05}^{D / d}$

Here, the value of D/d required to make the number of service life cycles Nn equal to the value of Nc when D/d = 40 is found to be 26.7. Consequently, if a service life equivalent to conditions under which general conventional elevator ropes have been used, that is, when D/d = 40, is to be ensured, the diameter of the inner layer rope 1 must be made less than or equal to 1/27 of a diameter of the sheaves. In other words, sheaves having a diameter greater than or equal to twenty-seven (27) times that of the inner layer rope 1 must be used.
In the above elevator rope, because the diameters of all of the wires 5, 6, 10, and 11 are set to less than or equal to 1/400 of the diameter of the sheaves with which they are used, there is no loss of bending fatigue service life even if the diameter of the sheaves with which they are used is reduced.
In addition, since the outer layer 8 is exposed externally, wire breakages in the outer peripheral wires 11 can be checked visually. Thus, it is no longer necessary to use flaw detecting devices, etc., to inspect the wire breakage state, enabling maintenance costs to be reduced.
By using high-strength, long-life, high-friction elevator ropes 36, sufficient rope service life can be maintained in an elevator apparatus such as that described above even if the diameter of the car guide pulley 41 and the counterweight guide pulley 42 is made greater than or equal to fifteen (15) times and less than or equal to twenty (20) times the diameter of the elevator ropes 36.
Consequently, the car guide pulley 41 and the counterweight guide pulley 42 can be disposed in the space above the car 37 without increasing the height dimensions of the hoistway 31, and it is not necessary to widen the cross sectional area of the hoistway 31.
Moreover, in practical use, it is preferable to make the diameter of the car guide pulley 41 and the counterweight guide pulley 42 greater than or equal to fifteen (15) times the diameter of the rope in elevator apparatuses not operating frequently, and greater than or equal to twenty (20) times in busy elevator apparatuses to enable sufficient service life to be ensured. Furthermore, in order to suppress the height dimensions of the hoistway 31, it is preferable to make the diameter of guide pulleys 41 and 42 less than or equal to thirty (30) times the diameter of the rope. In particular, if the diameter of the guide pulleys 41 and 42 is set within a range of fifteen to twenty (15 to 20) times the diameter of the rope, the height dimensions of the hoistway 31 can be reduced effectively. In addition, if the diameter of the guide pulleys 41 and 42 is set within a range of the installed height of the driving machine 33, the height dimensions of the hoistway 31 can be reduced even more effectively.

Embodiment 2

Next, Figure 7 is a cross section of an elevator rope according to Embodiment 2 of the present invention. In the figure, an inner layer rope 23 has: a core rope 24; and a plurality of inner layer strands 25 disposed on outer peripheral portions of the core rope 24. The core rope 24 has a plurality of core strands 26. Each of the core strands 26 is constructed by twisting a plurality of steel wires 27 together with each other.
The inner layer strands 25 are constructed by twisting a plurality of steel wires 28 together with each other. The cross sections of the wires 28 in the inner layer strands 25 are modified by compressing the inner layer strands 25 from an outer periphery. The cross sections of the wires 27 in the core strands 26 are modified by compressing the core strands 26 from an outer periphery. The rest of the construction is similar to that of Embodiment 1.
In an elevator rope of this kind, by twisting the inner layer strands 25 and the core strands 26 during manufacturing to approximately 5 percent (5%) greater than their finished diameter, then passing them through a die of the finished diameter, the wires are made to come into contact with each other along surfaces or lines instead of points. Thus, the packing density of the wires 27 and 28 can be increased. Contact pressure among the wires 27 and among the wires 28 is also reduced, suppressing abrasion of the wires 27 and 28. In addition, disarray in the inner layer strands 25 and the core strands 26 is prevented, enabling extension of service life.
Moreover, the shape of the cross sections of the wires 10 and 11 in the outer layer strands 9 can also be modified by compressing the outer layer strands 9 from an outer periphery.

Embodiment 3

Next, Figure 8 is a side elevation showing an elevator rope according to Embodiment 3 of the present invention cut away in layers. In this example, inner layer strands 3, core strands 4, and outer layer strands 9 are twisted the same direction as each other. The rest of the construction is similar to that of Embodiment 1.
If elevator ropes of this kind are used, because the strands 3, 4, and 9 are twisted in a single direction, load sharing among the strands 3, 4, and 9 is less likely to become nonuniform when a load acts on the elevator ropes or even if twisting is loosened by repetitive bending, enabling high strength to be maintained and enabling extension of service life.
Moreover, the ropes shown in Embodiments 1 to 3, which have multilayered constructions, have characteristics by which the load burden rate of each of the layers is changed by fatigue over time. Thus, the strength burden ratio in layers in which damage proceeds preferentially is reduced, although this varies depending on the construction of the ropes. In other words, it is preferable to detect abnormalities in a weakest layer by setting the strength of one layer to twenty to eighty percent (20% to 80%) and to change the ropes before the overall strength deteriorates significantly.
For example, it is preferable for the sum total strength of the strengths of the outer layer strands 9, which are in the weakest layer where bending stresses are at their greatest, to be set to within twenty percent (20%) of the overall strength of the elevator rope. Thus, even if the outer layer strands 9 break, a residual strength of nearly 80 percent (80%) can be ensured in the inner layer rope 1 alone, enabling reliability to be improved.
Moreover, in the case of constructions in which the service life of the inner layer rope 1 is shorter than that of the outer layer strands 9, such as when the core strands 4 are not coated, or will not have their shapes modified, etc., it is effective to make the strength of the inner layer rope 1 twenty percent (20%) of the overall strength, and preform the outer layer strands 9.

Claims

An elevator rope comprising:
an inner layer rope (1, 23) having a plurality of inner layer strands (3, 25) in which a plurality of steel wires (6, 28) are twisted together;

an inner layer coating body (7) made of resin coated onto an outer periphery of said inner layer rope (1, 23); and
characterized by comprising an outer layer (8) having at least twelve outer layer strands (9) in which a plurality of steel wires (10, 11) are twisted together disposed on an outer peripheral portion of said inner layer coating body (7),
wherein the diameters of the outer layer strands (9) are smaller than the diameters of all of the inner layer strands (3, 25).
An elevator apparatus comprising:
a driving machine (33) having a drive sheave (35) on which a rope groove (45) is disposed;

an elevator rope (36) according to claim 1 inserted into said rope groove (45) and wound around said drive sheave (35); and

a car (37) and a counterweight (39) suspended inside a hoistway (31) by said elevator rope (36) and raised and lowered by said driving machine (33),

wherein
a surface of said rope groove (45) contacting said elevator rope (36) is composed of a high-friction resin material.
The elevator apparatus according to claim 2, characterized in that:
a coefficient of friction of said high-friction resin material is greater than or equal to 0.2.
The elevator apparatus according to claim 2, characterized in that:
said high-friction resin material is polyurethane resin.
The elevator apparatus according to claim 2, characterized in that:
a diameter of said inner layer rope (1, 23) is set to less than or equal to 1/27 of a diameter of said drive sheave (35).
The elevator apparatus according to claim 2, characterized in that:
a diameter of each of said wires (6, 28, 10, 11) is set to less than or equal to 1/400 of a diameter of said drive sheave (35).
The elevator apparatus according to claim 2, characterized in that:
said driving machine (33) is disposed in an upper portion of said hoistway (31) such that a rotating shaft of said drive sheave (35) extends vertically;

a car guide pulley (41) for directing said elevator rope (36) extending from said drive sheave (35) toward said car (37), and a counterweight guide pulley (42) for directing said elevator rope (36) extending from said drive sheave (35) toward said counterweight (39) are disposed in an upper portion of said hoistway (31);

a rope groove (45) into which said elevator rope (36) is inserted is disposed on said car (37) and counterweight guide pulleys (41, 42); and

a surface of said rope groove (45) contacting said elevator rope (36) in at least one of said car (37) and counterweight guide pulleys (41, 42) is composed of said high-friction resin material.
The elevator apparatus according to claim 7, characterized in that:
said driving machine (33), said car guide pulley (41), and said counterweight guide pulley (42) are disposed so as to overlap with said car (37) in a vertical plane of projection; and

a diameter of said car guide pulley (41) and said counterweight guide pulley (42) is greater than or equal to fifteen times and less than or equal to thirty times a diameter of said elevator rope (36).