EP2441723B1

EP2441723B1 - Rope for elevators and process for producing same

Info

Publication number: EP2441723B1
Application number: EP09845774.0A
Authority: EP
Inventors: Atsushi Mitsui
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2009-06-08
Filing date: 2009-06-08
Publication date: 2019-07-24
Anticipated expiration: 2029-06-08
Also published as: EP2441723A1; WO2010143249A1; EP2441723A4; CN102459052B; JP5404782B2; KR101414330B1; JPWO2010143249A1; CN102459052A; KR20110127262A

Description

TECHNICAL FIELD

The present invention relates to an elevator rope that can be used as a main rope that suspends a car, for example, and to a manufacturing method therefor.

BACKGROUND ART

In conventional elevator ropes, a plurality of steel strands are stranded onto an outer circumference of a core rope that is made of a fiber bundle. Generally, the core rope is configured by stranding three core rope strands that are each formed by stranding a large number of yarns. Density is increased by shaping the core rope strands by compression from the outer circumference as they are stranded with the steel strands. The shape of the rope thereby stabilizes, and gaps among the steel strands are thereby maintained appropriately (see JP HEI 5-262478 A , for example).
EP 0357883 A2 is related to the preamble of claims 1 and 2.

SUMMARY OF THE INVENTION

PROBLEM TO BE SOLVED BY THE INVENTION

In conventional elevator ropes such as that described above, in order to stabilize the shape of the ropes and also maintain the gaps among the steel strands appropriately, it is necessary to raise the packing density (mass per unit length) relative to the diameter of the core rope, but particularly as the rope diameter increases, the accumulation of gaps inside the core rope increases, and it becomes difficult ensure the packing density of the core rope while keeping the core rope diameter at a predetermined size. In contrast thereto, if attempts are made to increase the diameters of the respective core rope strands to ensure the packing density, a large pressing force is necessary in order to control the rope diameter during stranding with the steel strands, and the surfaces of the steel strands may be damaged, or the fibers of the core rope may be damaged, whereby strength and service life are lost.
The present invention aims to solve the above problems and an object of the present invention is to provide an elevator rope and a manufacturing method therefor that enables packing density of a core rope to be increased while preventing damage to the core rope and steel strands even if rope diameter is large.

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 the features of claim 1.
According to another aspect of the present invention, there is provided an elevator rope manufacturing method including the features of claim 2.
According to a preferred embodiment of the present invention, there is provided an elevator rope manufacturing method including steps of: coating a core rope strand coating body onto an outer circumference of each of a plurality of core rope strands that are constituted by fiber bundles; forming a core rope by stranding the core rope strands that are coated with the core rope strand coating bodies with each other; forming a core rope coating body by passing the core rope through a heated die to integrate the core rope strand coating bodies in which the core rope strands are coated separately; and stranding a plurality of steel strands onto an outer circumference of the core rope coating body.

EFFECTS OF THE INVENTION

In an elevator rope according to the present invention, because a core rope that is constituted by a fiber bundle is coated with a resin core rope coating body, and steel strands are stranded onto an outer circumference thereof, packing density of the core rope can be increased while preventing damage to the core rope and steel strands even if rope diameter is large.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1, which is not in accordance with the present invention;
Figure 2 is a cross section that shows an intermediate state during manufacturing of the elevator rope from Figure 1;
Figure 3 is a cross section of a pressure die that is used when a resin coating body from Figure 2 is extruded;
Figure 4 is a cross section of an example of a tube die;
Figure 5 is a cross section that shows a first example of a shape of a resin coating body when the tube die from Figure 4 is used;
Figure 6 is a cross section that shows a second example of a shape of a resin coating body when the tube die from Figure 4 is used;
Figure 7 is a cross section that shows an intermediate state during manufacturing of an elevator rope according to Embodiment 2, which is in accordance with the present invention;
Figure 8 is a cross section that shows an intermediate state during manufacturing of an elevator rope according to Embodiment 3, which is in accordance with the present invention;
Figure 9 is a cross section that shows a state in which a core rope from Figure 8 has been passed through to a heated die and shaped; and
Figure 10 is a side elevation that shows an example of an elevator apparatus to which the elevator rope of Embodiments 1, 2 or 3 is applied.

DESCRIPTION OF EMBODIMENTS

An embodiment for implementing 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. In the figure, a core rope 1 is disposed centrally in an elevator rope (a wire rope). The core rope 1 is configured by stranding three core rope strands 2 with each other and pressing from an outer circumference. Each of the core rope strands 2 is constituted by a large number of yarns that are formed by bundling fibers.
The outer circumference of the core rope 1 is coated by a resin core rope coating body 3. Polyethylene or polypropylene, for example, is used as a material for the core rope coating body 3.
A plurality of steel strands (in this case, eight) are stranded onto the outer circumference of the core rope coating body 3. Each of the steel strands 4 is configured by stranding a plurality of steel wires. More specifically, the steel strands 4 have: a core wire that is disposed centrally; an intermediate layer that is constituted by a plurality of intermediate wires that are stranded onto an outer circumference of the core wire; and an outer layer that is constituted by a plurality of outer circumferential wires that are stranded onto an outer circumference of the intermediate layer. Diameters of the intermediate wires are smaller than diameters of the core wire and the outer circumferential wires.
The core rope coating body 3 is interposed between mutually-adjacent steel strands 4. The core rope coating body 3 is also interposed between the steel strands 4 and the core rope 1. In addition, a plurality of grooves 1a that have V-shaped cross sections are formed on the outer circumference of the core rope 1 between mutually-adjacent core rope strands 2, and the core rope coating body 3 also enters the grooves 1a.
Next, a method for manufacturing the elevator rope from Figure 1 will be explained. When the elevator rope from Figure 1 is manufactured, first, as shown in Figure 2, the three core rope strands 2, which have circular cross sections, are stranded with each other, and the core rope coating body 3 is coated onto the outer circumference thereof. Here, the core rope coating body 3 is coated onto the outer circumference of the core rope 1 by extrusion using a pressure die 5 such as that shown in Figure 3.
A core rope insertion channel 5a through which the core rope 1 is inserted is disposed centrally inside the pressure die 5. A cylindrical resin flow channel 5b is disposed radially outside the core rope insertion channel 5a inside the pressure die 5. A diameter of the resin flow channel 5b is gradually reduced near a downstream end (on the left in Figure 3), and the downstream end of the resin flow channel 5b is merged with the core rope insertion channel 5a inside the pressure die 5. In other words, resin that is made to flow into the resin flow channel 5b is coated onto the outer circumference of the core rope 1 while being pressurized inside the pressure die 5. The resin thereby fills gaps on the outer circumference of the core rope 1.
In contrast to that, if a tube die (a sheath die) 6 such as that shown in Figure 4 is used, the resin flow channel 6b does not merge with the core rope insertion channel 6a inside the tube die 6, and the outer circumference of the core rope 1 is covered with a resin tube (an outer cover) that is formed outside the tube die 6. For this reason, it is difficult to fill the gaps on the outer circumference of the core rope 1 with the resin, and the core rope coating body 3 assumes a form such as that shown in Figures 5 or 6. Specifically, in Figure 5, the core rope coating body 3 is a cylindrical shape, and in Figure 6, the core rope coating body 3 has adhered to the outer circumference of the core rope 1 at a uniform thickness, both of which are less effective for increasing the packing density of the core rope.
The core rope coating body 3 is coated onto the outer circumference of the core rope 1, and then the steel strands 4 are stranded. Here, the core rope is shaped by compression from the outer circumference with the core rope coating body 3 interposed to increase density. The core rope coating body 3 also enters between the mutually-adjacent steel strands 4.
In an elevator rope of this kind, because the core rope coating body 3 is coated onto the outer circumference of the core rope 1, the core rope 1 can be shaped by compression with the core rope coating body 3 interposed, enabling the packing density of the core rope 1 to be increased while preventing damage to the core rope 1 and the steel strands 4 even if rope diameter is large.
Since the core rope coating body 3 fills the gaps on the outer circumference of the core rope 1 without having to press unnecessarily, or to deform the core rope 1, rigidity of the core rope 1 can be maintained when the steel strands 4 are stranded, thereby also enabling damage to the core rope 1 and the steel strands 4 to be prevented.
In addition, since the core rope coating body 3 is deformed and enters between the steel strands 4 and between the core rope strands 2, and also has higher rigidity and is less prone to deform than conventional core ropes that only have fiber cores, contact pressure between the steel strands 4 and the core rope strands 2 is reduced, enabling fretting wear to be reduced.
Furthermore, if the thickness of the core rope coating body 3 is not increased more than necessary, minute cracks arise in the core rope coating body 3 due to repeated flexing, but a lubricating oil that is contained in the core rope 1 can also be supplied to the steel strands 4 through these gaps to maintain satisfactory lubrication.
Moreover, minute pores may also be predisposed in the core rope coating body 3 in order to supply lubricating oil that is contained in the core rope 1 to the steel strands 4.

Embodiment 2

Next, Figure 7 is a cross section that shows an intermediate state during manufacturing of an elevator rope according to Embodiment 2 of the present invention. In this example, core rope strand coating bodies 7 are applied to an outer circumference of respective core rope strands 2, and a core rope coating body 3 is formed on an outer circumference of a core rope 1 that is formed by stranding the core rope strands 2 thus coated. The core rope strand coating bodies 7 are constituted by a resin that is similar to that of the core rope coating body 3.
The core rope strand coating bodies 7 are coated onto the outer circumference of the core rope strands 2 by extrusion using a tube die 6 such as that shown in Figure 4. The core rope coating body 3 is formed using a pressure die 5 such as that shown in Figure 3. The rest of the configuration is similar to Embodiment 1, steel strands 4 being stranded onto the outer circumference of the core rope coating body 3.
A lubricating oil is impregnated into the core rope 1, but since resin pressure acts on the core rope 1 when formed by the pressure die 5, the lubricating oil is prone to be squeezed out in an extruder die portion. In contrast to that, in the case of the tube die 6, since the forming method is such that a preformed tube is placed over the core rope strands 2 outside the die, very little lubricating oil is squeezed out during formation. Since the cross sections of the core rope strands 2 are shapes that are nearly circular compared to the core rope 1, even if formed by the tube die 6, the packing density relative to the diameter changes very little from when formed by the pressure die 5. From the above, a core rope 1 in which packing density is increased can be obtained while maintaining the oil content of the core rope 1 by configuring as described above.

Embodiment 3

Next, Figures 8 and 9 are cross sections that show intermediate states during manufacturing of an elevator rope according to Embodiment 3 of the present invention. In this example, as shown in Figure 8, core rope strand coating bodies 7 are applied to an outer circumference of respective core rope strands 2, and the core rope strands 2 thus coated are stranded. It is desirable to use a tube die 6 in the formation of the core rope strand coating bodies 7 in a similar manner to Embodiment 2. The core rope from Figure 8 is subsequently passed through a heated die to form the shape that is shown in Figure 9. The core rope strand coating bodies 7 that coat the core rope strands 2 separately are thereby integrated with each other to form a core rope coating body 3. The rest of the configuration is similar to Embodiment 1, steel strands 4 being twisted together on the outer circumference of the core rope coating body 3.
According to a configuration of this kind, a core rope in which packing density is high and oil content is maintained can also be configured.
Now, Figure 10 is a side elevation that shows an example of an elevator apparatus to which the elevator rope of Embodiments 1, 2 or 3 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. A safety gear 23 that makes the car 19 perform an emergency stop by engaging with the car guide rails 21 is mounted to the car 19.
Moreover, the type of elevator apparatus to which the elevator ropes according to the present invention are applied is not limited to the type in Figure 10. 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.

Claims

An elevator rope comprising:
a core rope (1) that is constituted by a fiber bundle;

a resin core rope coating body (3) that is coated onto an outer circumference of the core rope (1); and

a plurality of steel strands (4) that are stranded onto an outer circumference of the core rope coating body (3), wherein

the core rope (1) has a plurality of core rope strands (2) that are stranded with each other; characterized in that:
a resin core rope strand coating body (7) is coated onto an outer circumference of each of the core rope strands (2).
An elevator rope manufacturing method including steps of:
coating a resin core rope coating body (3) onto an outer circumference of a core rope (1) that is constituted by a fiber bundle; and

stranding a plurality of steel strands (4) onto an outer circumference of the core rope coating body (3), characterized in that

the core rope (1) is configured by coating a core rope strand coating body (7) onto an outer circumference of each of a plurality of core rope strands (2) that are constituted by fiber bundles, and then stranding the core rope strands (2) that are coated with the core rope strand coating bodies (7) with each other.
An elevator rope manufacturing method according to claim 2, further including the step of:
forming a core rope coating body (3) by passing the core rope (1) through a heated die to integrate the core rope strand coating bodies (7) in which the core rope strands (2) are coated separately.
An elevator rope manufacturing method according to either of claims 2 or 3, wherein coating of the core rope strand coating bodies (7) onto the core rope strands (2) is performed by extrusion using a tube die (6).