HK1170524B - Metal rope, elevator provided with metal rope, and use of lubricant for lubricating the metal rope - Google Patents

Description

Metal rope, elevator provided with metal rope and use of lubricant for lubricating metal rope

Technical Field

The object of the invention is a metal rope, an elevator provided with a metal rope and the use of a lubricant for lubricating the metal rope.

Background

The ropes, more particularly the hoisting ropes, i.e. the suspension ropes, of an elevator or other hoisting apparatus, which are braided from metal wires, are usually lubricated with some suitable lubricant. Lubrication improves the handling of the rope and reduces the wear of the rope, in which case the service life of the rope is extended. Lubrication also prevents rusting of the rope. Ropes are often lubricated in connection with rope manufacturing, for example so that when the strands of the rope are braided from steel wire, the lubricant is sprayed into the strands to be manufactured.

According to one prior art method, the lubricant used is based on paraffin wax. However, one problem when using paraffin is that the oil film structure, in this case oil bound by paraffin, can easily separate from the rope when the rope becomes hot. Another problem with paraffin-based lubricants is that the traction sheave-rope contact becomes smoother at higher temperatures, due to which it can be difficult to make the coefficient of friction between the traction sheave and the rope meet the values required by elevator regulations. If the friction coefficient is too small, the ropes will slip on the traction sheave, which causes problems and may also be a safety risk. Other relatively thin lubricants have the same type of problem as the oil mixed with the paraffin wax.

Generally, it is desirable to make elevators and elevator structures as light as possible, in which case the elevator will be cheaper to manufacture and install. However, as the elevator car and counterweight become lighter, the friction between the elevator ropes and the traction sheave is simultaneously reduced. The reduction of friction thus limits the manufacture of lighter elevators; the general aim is to achieve high friction but so that the rope does not wear too quickly.

Disclosure of Invention

The idea of the invention is to equip an elevator with an elevator rope of the type in which a lubricant containing solid additives is used as a lubricant instead of oil, paraffin or oil mixed with paraffin, whereby the friction between the elevator rope and the traction sheave will be greater than the friction of an elevator rope lubricated according to prior art.

The object of the present invention is to eliminate the above-mentioned drawbacks and to achieve a metal rope of a traction sheave elevator, such as a suspension rope, which is lubricated with a lubricant of the grease type, the friction coefficient between the suspension rope and the traction sheave being greater than in prior-art solutions. In addition, one object is to achieve a suspension rope of a traction sheave elevator, which suspension rope has a longer service life than before. Yet another object is to achieve a suspension rope of a traction sheave elevator, in which the lubricant stays well on the rope during operation of the rope. The object of the invention is also to achieve a traction sheave elevator in which the suspension ropes are lubricated with a lubricant of the grease type. Further, the object of the invention is to achieve the use of a lubricant of the grease type for lubricating the metal ropes, e.g. the suspension ropes, of an elevator.

Some embodiments of the invention are also discussed in the description part of the present application. The inventive content may also consist of several separate inventions, especially if the invention is considered in the light of expressions or implicit sub-tasks or from the point of view of advantages or categories of advantages achieved. Likewise, the different details provided in connection with each embodiment of the invention are also applicable to the other embodiments.

One of the advantages of the solution according to the invention is that the friction between the elevator ropes and the rope grooves of the traction sheave is greater than that of elevator ropes lubricated with conventional petroleum. Another advantage is that the control of the sliding of the elevator ropes on the traction sheave is also improved due to better frictional traction. The advantages provided from the above result in the advantage that the torque of the motor can be used more efficiently, since the ratio of the rope forces on the different sides of the traction sheave can be made larger, which enables the ratio of the net payload and the self-weight of the car to be improved. Another advantage is that the greater friction allows for a smaller diameter of the traction sheave or correspondingly a smaller contact angle of the elevator ropes and the traction sheave. One advantage is also that a smaller and lighter structure can be used in the elevator, which also results in a reduction of costs, due to better friction traction. A further advantage is that the elevator ropes do not rust or wear easily, so that the life of the ropes is longer compared to ropes lubricated e.g. with paraffin. Another advantage is that the lubricant penetrates very well into the rope interior and remains well attached to the rope and does not easily separate therefrom or splash into other parts of the elevator.

An important aspect of the invention is to lubricate a part of the metal rope, in practice a steel rope, which may comprise non-metals, by means of a lubricant comprising at least oil and a thickener. The thickener in the lubricant comprises at least 10% of its mass. Depending on the thickener and additive, thickener content levels of 10-20% have resulted in very dry lubricants. If the thickener comprises at least about one third, the oil to lubricant adhesion is very easy. In practice, the percentage content of thickener must be kept below 90%, preferably below 85%, because enough lubricating oil is to be adhered to the lubricant. Suitably the thickener will constitute slightly more than one half of the components of the lubricant, most suitably about 60-75%.

The thickener comprises one or more solid additives of a softer material than the metal wires of the rope and is preferably non-organic. The thickener may comprise lithium, lithium compounds, calcium compounds, calcium carbonate, gypsum, talc, calcite, fluorite or apatite, or other materials suitable for the purpose, such as compounds comprising calcium.

The lubricant of the rope comprises oil, e.g. gear oil or bearing oil, which comprises about 15-80%, suitably less than one half, preferably about 20-30% of the mass of the lubricant (8).

The lubricant may also contain binders, dopants and additives. These add up to less than 15% by mass. The lubricant comprises, in addition to the oil and the thickener, a binder, the binder comprising 0-10% by mass.

Drawings

The invention will be described in more detail below by means of examples of embodiments of the invention with reference to the accompanying drawings, in which:

fig. 1 presents a schematic and simplified view of a traction sheave elevator with its rope tension diagram, seen from the side of the traction sheave;

fig. 2 shows a cross-section of a metal rope, e.g. a suspension rope, of an elevator lubricated by a lubricant;

fig. 3 shows graphs compiled on the basis of measurement results of the wear of elevator ropes lubricated in different ways;

fig. 4 presents a graph compiled on the basis of measurement results of the sliding percentages of two elevator ropes lubricated in different ways and the friction coefficient between the elevator ropes and the rope grooves.

Detailed Description

Fig. 1 presents a schematic and simplified view of a typical traction sheave elevator, which comprises an elevator car 1, a counterweight 2 and elevator ropes formed by elevator ropes 3 parallel to each other mounted between them. The elevator ropes 3 are guided in rope grooves dimensioned for the elevator ropes 3 to pass over a traction sheave 4 rotated by the hoisting machine of the elevator. When it rotates, the traction sheave 4 simultaneously moves the elevator car 1 and the counterweight 2 in the upward and downward direction due to friction.

Due to the difference between the counterweight 2 and the elevator car 1 plus the load in the elevator car at any given time, the rope force T exerted on the elevator ropes 3_CTWAnd T_CARWith different magnitudes on different sides of the traction sheave 4. When the elevator car 1 contains less than one-half of the nominal load, the counterweight is usually heavier than the elevator car 1 and the load. In this case the rope force T between the counterweight 2 and the traction sheave 4_CTWGreater than the rope force T between the elevator car 1 and the traction sheave 4_CAR. Correspondingly, when the elevator car 1 contains more than one-half of the rated load, the counterweight 2 is generally lighter than the elevator car 1 and the load. In this case the rope force between counterweight 2 and traction sheave 4T_CTWIs less than the rope force T between the elevator car 1 and the traction sheave 4_CAR. In the situation presented in fig. 1, the rope force between the elevator car 1 and the traction sheave 4 is T_CAR>T_CTW. As a result, the rope force T acting on the elevator ropes 3 in the rope grooves of the traction sheave 4_CTWAnd T_CARThe rope tension generated is not constant but increases when going from the counterweight 2 side to the elevator car 1 side. This increased rope tension is schematically represented in the tension diagram 5 shown in fig. 1. As explained earlier, this difference in tension tries to cause slipping of the elevator ropes 3 in the rope grooves. The tension difference across the traction sheave 4 is compensated in an effort by a controlled slip, which may be implemented, for example, due to greater friction.

Fig. 2 shows a cross-section of one metal rope, e.g. a suspension rope 3, of the elevator. The suspension rope 3 of the elevator comprises strands 7 braided together around a core 6, which strands are for their part braided e.g. from metal filaments, e.g. steel wires 9. The elevator ropes 3 have been lubricated in connection with rope manufacture by means of a lubricant 8. The lubricant 8 is located between the strands 7 and also between the metal filaments 9 of the strands, and the lubricant 8 is arranged to prevent the strands 7 and the metal filaments 9 from rubbing against each other. The lubricant 8 of the elevator rope 3 according to the invention also acts on the friction coefficient between the traction sheave 4 of the elevator and the elevator rope 3, increasing the friction compared to elevator ropes lubricated with lubricating oil according to the prior art.

The lubricant 8 of the suspension ropes of the elevator according to the invention comprises at least some base oil (base oil) suitable for the purpose, some thickener, i.e. solid additive, and, if desired, some binder. Base oils, more briefly referred to as "oils", are, for example, some suitable synthetic oils that contain various additives, such as anti-wear and anti-corrosion agents. The task of the oil is, inter alia, to prevent water from entering the rope 3 and to protect the rope against corrosion and wear. A lubricant of the anti-abrasion and possibly also anti-seize type can be applied as a lubricant for the elevator ropes 3 for this purpose according to the invention, even if there are some limitations caused by the application.

The thickener comprises one or more finely divided solid substances, which are, for example, aluminum-based, lithium-based, barium-based or calcium-based metal soaps. The thickener may also be a so-called lithium composition or calcium composition, in which case a large amount of metal soap is used together as the thickener. For example, one or more of the following are used as thickeners in the lubricant 8 according to the invention: lithium, lithium compounds, calcium compounds, calcium carbonate, gypsum, talc, calcite, fluorite or apatite, or some other material suitable for the purpose, for example some other compound comprising calcium. The thickener may also be a mixture of some of two or more of the above.

The thickener is a softer material than the steel of which the steel wire 9 of the elevator rope 3 is made, which prevents the lubricant 8 from grinding off the rope 3 by wear. The thickener is also arranged to act as a dry lubricant for the rope 3 and to bind the oil. In this case, the thickener functions as a material that stores oil and does not form an oil solution.

The binder is arranged to hold the other materials of the lubricant 8, i.e. the oil, and the thickener better together. The binder is, for example, an organic-based substance, such as a butyl compound, or another substance suitable for the purpose, such as a resin-based or wax-based substance.

The lubricant 8 is simply manufactured by mechanically mixing its different component parts with each other. The mixing ratio of the different components of the lubricant 8 is, for example, about 15-80%, preferably about 20-30% oil, for example about 10-85%, preferably about 65-75% thickener, and for example about 0-10%, suitably about 3-6%, for example 5% binder. The above percentage figures are in terms of weight percent. The structure of the lubricant 8 is pasty due to the large amount of thickener. With the aid of the binder and the thickener, the lubricant 8 stays well on the rope and does not easily separate.

The lubricant 8 according to the invention differs from conventional greases in that, in particular, it preferably comprises a very high proportion of thickener and less oil. The thickener may constitute, for example, up to 85%, in which case the proportion of base oil remains at most 15%. In contrast, for lubricating greases, the proportion of base oil in the grease is 80-90%, in which case the proportion of thickeners and other substances is kept only at 10-20%.

Fig. 3 shows a graph compiled on the basis of the measurement results obtained in the test of the wear of elevator ropes lubricated in different ways. Curves p1 and p2 represent ropes lubricated with paraffin according to the prior art, and curves n1 and n2 represent ropes lubricated with lubricant 8 according to the invention. The wear of the rope is tested by a test apparatus so that the rope is driven back and forth in the groove of the rope pulley and the wear of the rope is diagnosed from the reduction of the diameter of the rope.

As can be seen from fig. 3, the ropes p1 and p2, which were initially slightly over 4 mm thick and lubricated with a paraffin-based lubricant, thinned to 3.9 mm in diameter after approximately one million test cycles. After 150 ten thousand test cycles the ropes p1 and p2 appeared to have been substantially unsuitable for their use for this purpose. On the other hand, the ropes n1 and n2 lubricated with lubricant 8 according to the invention were not actually worn at all even during 500 ten thousand test cycles, as shown in fig. 3.

Fig. 4 shows a graph compiled from measurements obtained in the laboratory of the coefficient of friction of the rope grooves of the traction sheave 4 and the relation between the percentage of slip of the steel rope p1 lubricated with paraffin according to the prior art and the steel rope n1 lubricated with lubricant 8 according to the invention. The situation shown here is thus an empirically derived effective coefficient of friction between two objects sliding against each other and not a specific coefficient of friction for an individual material.

As can be seen from the graph, in the case of the steel wire rope lubricated with the paraffin-based lubricant according to the related art, which is represented by a curve p1 in fig. 4, the effective friction coefficient rises linearly and is relatively steep at the initial stage of sliding. At about 0.3% slip, the increase in effective coefficient of friction has slowed down, at this stage now about 0.08. Thereafter, as the slip increases, the rise in the effective coefficient of friction slows down even faster and does not increase here beyond a limit of about 0.1, even though the slip increases faster. In this case it is the case that the elevator ropes have lost their grip in the grooves of the traction sheave 4.

Accordingly, in the case of a steel cord lubricated with the lubricant 8 according to the invention, which is represented by curve n1 in fig. 4, the effective friction coefficient likewise rises linearly and relatively sharply in the initial phase of sliding. As the slip increases, the effective friction coefficient now also continues its increase, substantially linearly to a higher value than the effective friction coefficient of the rope represented by the curve p 1. With the rope n1 lubricated with the lubricant 8 according to the invention, the effective friction coefficient reaches a value of almost 0.14 as the sliding increases. In this case, the traction sheave 4 maintains a significantly greater clamping retention in the event of an accident and a value greater than 0.1, for example a value of about 0.14, can be used for the effective coefficient of friction in the dimensioning. This enables T of the rope force_CAR/T_CTWIn this case, it is possible to achieve a smaller moving mass, with the further result of smaller acceleration forces, lower energy consumption and smaller losses. In addition, material can be saved.

It is clearly demonstrated by the tests described above that the life of the elevator suspension ropes 3 lubricated with lubricant 8 is considerably longer than the life of elevator ropes lubricated with lubricants of the prior art, due to the high proportion of thickener contained in the lubricant 8, and that, in addition, the coefficient of friction between the ropes 3 and the traction sheave 4 is greater than when using conventional lubricants, which makes a more advantageous dimensioning possible.

In particular, a characteristic aspect of the elevator according to the invention is that the elevator is provided with suspension ropes 3 lubricated with a lubricant 8 containing a thickener, the load-bearing material of said ropes being metal, such as steel. The thickener in the lubricant of the suspension ropes 3 of the elevator comprises a suitable above-mentioned percentage of the total mass of the lubricant 8. In addition, the lubricant 8 may contain the above-described binder and other additives.

The use of the above-mentioned lubricant 8 comprising a thickener for lubricating a rope braided from metal wires is further characterized for the solution according to the invention.

It is obvious to the person skilled in the art that different embodiments of the invention are not limited to the examples described above, but that they may vary within the scope of the invention. Thus, for example, the composition of the lubricant and the mixing ratio of the different components may also differ from that disclosed above.

Likewise, it is obvious to the person skilled in the art that, instead of synthetic oils, mineral or vegetable oils suitable for this purpose can also be used as oils in the lubricant.

It is further obvious to the person skilled in the art that the zinc applied on the rope wires for the purpose of preventing corrosion suspending the rope wires can also be a thickener, i.e. a necessary solid additive.

Claims (25)

1. A rope (3) comprising metal as a load-bearing material, which rope comprises at least one or more strands (7) braided from metal filaments (9) and which rope (3) is lubricated with a lubricant (8), characterized in that the lubricant (8) in the rope (3) comprises at least oil and thickener, which thickener in the lubricant (8) comprises at least 65% or more of the mass of the lubricant (8).

2. A rope according to claim 1, characterized in that the thickener in the lubricant (8) of the rope (3) comprises 65-85% of the mass of the lubricant (8).

3. A rope according to claim 1, characterized in that the thickener in the lubricant (8) of the rope (3) comprises 65-75% of the mass of the lubricant (8).

4. A rope according to claim 1, 2 or 3, characterized in that the metal wires of the rope (3) are steel wires and the thickener comprises one or more solid additives softer than the material of the steel wires (9) of the rope (3).

5. A rope according to claim 1, 2 or 3, charac teri z ed in that said thickener comprises lithium, a lithium compound, calcium, or a calcium compound.

6. A rope according to claim 1, 2 or 3, charac teri z ed in that the thickener comprises a compound comprising calcium.

7. A rope according to claim 1, 2 or 3, charac teri z ed in that the thickener comprises calcium carbonate, gypsum, talc, calcite, fluorite or apatite, or some other material suited to the purpose.

8. A rope according to any one of the preceding claims 1-3, charac teri z ed in that the lubricant (8) of the rope (3) comprises oil, which oil comprises 15-80% of the mass of the lubricant (8).

9. A rope according to any one of the preceding claims 1-3, charac teri z ed in that the lubricant (8) of the rope (3) comprises oil, which oil comprises 20-30% of the mass of the lubricant (8).

10. A rope according to any one of the preceding claims 1-3, charac teri z ed in that the lubricant (8) of the rope (3) comprises, in addition to oil and thickener, a binder comprising 0-10% of the mass of the lubricant (8).

11. Rope according to any one of the preceding claims 1-3, characterized in that the thickener in the lubricant (8) is non-organic and comprises one or more solid additives of a softer material than the metal wires of the rope.

12. Traction sheave elevator, comprising at least an elevator car (1), a possible counterweight (2) and a number of suspension ropes (3) for moving the elevator car, which suspension ropes are guided to pass over a traction sheave (4) provided with a hoisting machine and which suspension ropes (3) are lubricated with a lubricant (8), characterized in that the lubricant (8) of the suspension ropes (3) of the elevator comprises at least oil and thickener, which thickener in the lubricant (8) comprises at least 65% or more of the mass of the lubricant (8).

13. Traction sheave elevator according to claim 12, characterized in that the thickener in the lubricant (8) comprises 65-85% of the mass of the lubricant (8).

14. Traction sheave elevator according to claim 12, characterized in that the thickener in the lubricant (8) comprises 65-75% of the mass of the lubricant (8).

15. Traction sheave elevator according to claim 12, characterized in that the thickener in the lubricant (8) of the suspension ropes (3) of the elevator comprises calcium carbonate, gypsum, talc, calcite, fluorite or apatite, or some other material suited to the purpose.

16. Traction sheave elevator according to claim 12, characterized in that the thickener in the lubricant (8) of the suspension ropes (3) of the elevator comprises a compound containing calcium.

17. Traction sheave elevator according to any of claims 12-16, characterized in that the lubricant (8) of the suspension ropes (3) of the elevator contains oil, which oil comprises 15-70% of the mass of the lubricant (8).

18. Traction sheave elevator according to any of claims 12-16, characterized in that the lubricant (8) of the suspension ropes (3) of the elevator contains oil, which oil comprises 20-30% of the mass of the lubricant (8).

19. Traction sheave elevator according to any of claims 12-16, characterized in that the lubricant (8) of the suspension ropes (3) of the elevator contains, in addition to oil and thickener, a binder comprising 0-10% of the mass of the lubricant (8).

20. Traction sheave elevator according to any of claims 12-16, characterized in that the thickener in the lubricant (8) is non-organic and comprises one or more solid additives of a material softer than the metal wires of the rope.

21. Use of a lubricant (8) comprising at least an oil and a thickener, said thickener in said lubricant (8) comprising at least 65% or more of the mass of said lubricant (8), for lubricating a rope (3) comprising metal as a load-bearing material.

22. Use of a lubricant (8) according to claim 21, the rope (3) being a steel wire rope.

23. Use of a lubricant (8) according to claim 21, the lubricant comprising at least oil and thickener, the thickener in the lubricant (8) comprising at least 65% or more of the mass of the lubricant (8), for lubricating the suspension ropes (3) of a traction sheave elevator.

24. Use of a lubricant (8) comprising at least oil and non-organic thickener, the thickener in the lubricant (8) comprising at least 65% or more of the mass of the lubricant and further comprising one or more solid additives softer than the material of the metal wires of the rope, for lubricating a rope (3) comprising metal as a load-bearing material.

25. Use of a lubricant (8) according to claim 24, the rope (3) being a steel wire rope.