Metal rope and lubricant

Abstract

The object of the invention is a traction sheave elevator and a rope that contains metal as a load-bearing material, such as the suspension rope of an elevator, which rope comprises at least one or more strands laid from metal wires and which rope is lubricated with a lubricant. Another object is the use of the aforementioned lubricant for lubricating the rope. The lubricant comprises at least oil and thickener, which thickener in the lubricant comprises at least 10% or more of the mass of the lubricant.

Claims

1. A rope containing metal as a load-bearing material, the rope comprising: at least one strand laid from metal wires; wherein the rope is lubricated with a lubricant including at least oil and thickener, the thickener being greater than 65% of the mass of the lubricant, and the thickener contains at least one of lithium, lithium complex, calcium, calcium complex, calcium carbonate, gypsum, talcum, calcite, fluorite or apatite, and a compound containing calcium.

2. The rope according to claim 1, wherein the oil is in an amount greater than 15% and less than 35% of the mass of the lubricant.

3. The rope according to claim 2, wherein the oil is in an amount greater than 20% and less than 30% of the mass of the lubricant.

4. The rope according to claim 1, wherein the thickener is in the amount of greater than 65% and less than about 85% of the mass of the lubricant.

5. The rope according to claim 1, wherein the metal wires of the rope are steel wires and the thickener includes one or more solid additives of a material that is softer than the steel wires of the rope.

6. The rope according to claim 1, wherein the lubricant of the rope contains, in addition to the oil and the thickener, a binding agent in the amount of greater than 0 and less than 10% of the mass of the lubricant.

7. A traction sheave elevator, comprising: at least an elevator car; and a plurality of suspension ropes configured to move the elevator car, the plurality of suspension ropes passing over a traction sheave provided with a hoisting machine, and the plurality of suspension ropes being lubricated with a lubricant including at least oil and thickener; wherein the thickener is greater than 65% of the mass of the lubricant, and the thickener contains at least one of lithium, lithium complex, calcium, calcium complex, calcium carbonate, gypsum, talcum, calcite, fluorite or apatite, and a compound containing calcium.

8. The traction sheave elevator according to claim 7, wherein the oil is in an amount of greater than 15% and less than 35% of the mass of the lubricant.

9. The traction sheave elevator according to claim 8, wherein the oil is in an amount greater than 20% and less than 30% of the mass of the lubricant.

10. The traction sheave elevator of claim 7, wherein the thickener is in the amount of greater than 65% and less than or equal to about 85% of the mass of the lubricant.

11. The traction sheave elevator of claim 10, wherein the thickener in the lubricant is in an amount greater than 65% and less than 75% of the mass of the lubricant.

12. The traction sheave elevator according to claim 7, wherein the lubricant includes, in addition to the oil and the thickener, a binding agent in the amount of greater than 0 and less than 10% of the mass of the lubricant.

13. A rope containing metal as a load-bearing material, the rope comprising: at least one strand having metal wires, the rope being lubricated with a lubricant; wherein the lubricant includes at least oil and thickener, the thickener being greater than 65% of the mass of the lubricant, and the thickener contains at least one of lithium, lithium complex, calcium, calcium complex, calcium carbonate, gypsum, talcum, calcite, fluorite or apatite, and a compound containing calcium.

14. A rope containing metal as a load-bearing material, the rope comprising: at least one strand laid from metal wires; wherein the rope is lubricated with a lubricant including at least oil and thickener, the thickener being greater than 65% of the mass of the lubricant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the invention will be described in detail by the aid of an example of its embodiment with reference to the attached drawing, wherein

(2) FIG. 1 presents a diagrammatic and simplified view of one traction sheave elevator with its rope tension chart as viewed from the side of the traction sheave,

(3) FIG. 2 presents a cross-section of one metal rope, such as a suspension rope of an elevator, lubricated with a lubricant,

(4) FIG. 3 presents a graph, compiled on the basis of measurement results, of the wearing of elevator ropes lubricated in a different way, and

(5) FIG. 4 presents a graph, compiled on the basis of measurement results, of the ratio of the slip percentage of two elevator ropes lubricated in different ways and also of the friction factor between the elevator rope and the rope groove.

DETAILED DESCRIPTION

(6) FIG. 1 presents a diagrammatic and simplified view of one typical traction sheave elevator, which comprises an elevator car 1, a counterweight 2 and, fixed between these, elevator roping formed of elevator ropes 3 that are parallel to each other. The elevator ropes 3 are guided to pass over the traction sheave 4 rotated by the hoisting machine of the elevator in rope grooves dimensioned for the elevator ropes 3. As it rotates, the traction sheave 4 at the same time moves the elevator car 1 and the counterweight 2 in the up direction and down direction, due to friction.

(7) Owing to the difference between the counterweight 2 and the elevator car 1 plus the load at any given time in the car, the rope forces T.sub.CTW and T.sub.CAR exerted on the elevator ropes 3 are of 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 generally heavier than the elevator car 1 with load. In this case the rope force T.sub.CTW between the counterweight 2 and the traction sheave 4 is greater than the rope force T.sub.CAR between the elevator car 1 and the traction sheave 4. Correspondingly, when the elevator car 1 contains over one-half of the nominal load, the counterweight 2 is generally lighter than the elevator car 1 with load. In this case the rope force T.sub.CTW between the counterweight 2 and the traction sheave 4 is smaller than the rope force T.sub.CAR between the elevator car 1 and the traction sheave 4. In the situation presented in FIG. 1, the rope force between the elevator car 1 and the traction sheave 4 is T.sub.CAR>T.sub.CTW. As a consequence, the rope tension acting on the elevator ropes 3 that is produced by the rope forces T.sub.CTW and T.sub.CAR in the rope grooves of the traction sheave 4 is not constant, but instead increases when going from the counterweight 2 side to the elevator car 1 side. This growing rope tension is diagrammatically presented in the tension chart 5 drawn in FIG. 1. As explained earlier, this tension difference tries to cause slipping of the elevator ropes 3 in the rope grooves. It is endeavored to compensate for the tension difference across the traction sheave 4 with a controlled slip, which can be implemented e.g. owing to the larger friction.

(8) FIG. 2 presents a cross-section of one metal rope, such as a suspension rope 3 of an elevator. The suspension rope 3 of the elevator comprises strands 7 laid together around a core 6, which strands for their part are laid e.g. from metal wires, such as from steel wires 9. The elevator rope 3 has been lubricated with lubricant 8 in connection with the manufacture of the rope. Lubricant 8 is between the strands 7 and also between the wires 9 of the strands, and the lubricant 8 is arranged to protect the strands 7 and the wires 9 from rubbing against each other. The lubricant 8 of the elevator rope 3 according to the invention also acts on the friction factor between the elevator rope 3 and the traction sheave 4 of the elevator, increasing the friction compared to elevator ropes lubricated with lubricating oil according to prior art.

(9) The lubricant 8 of a suspension rope 3 of an elevator according to the invention comprises at least some base oil suited to the purpose, some thickener, i.e. solid additive and also if necessary some binder agent. The base oil, more briefly referred to as oil, is e.g. some suitable synthetic oil that contains various additives, such as e.g. wear resistance agents and corrosion resistance agents. The task of the oil is, among other things, to prevent water from entering the rope 3 and to protect the rope from corrosion and wear. Anti-fretting and possibly also anti-seize types of lubricants are applicable to the purpose according to the invention as a lubricant of an elevator rope 3, even though there are restrictions caused by the application.

(10) Thickener comprises one or more fine-grained solid substances, which are e.g. aluminium-based, lithium-based, barium-based or calcium-based metal soaps. The thickener can also be so-called lithium complex or calcium complex, in which case a number of metal soaps are used together as a thickener. For example, one or more of the following are used as a thickener in the lubricant 8 according to the invention: lithium, lithium complex, calcium, calcium complex, calcium carbonate, gypsum, talcum, calcite, fluorite or apatite, or some other material suited to the purpose, e.g. some other compound containing calcium. The thickener can also be a mixture of some of the aforementioned two or more substances.

(11) Thickener is of softer material than the steel of the steel wires 9, from which the elevator rope 3 is manufactured, which prevents the lubricant 8 wearing off the rope 3 by abrasion. The thickener is also arranged to function as a dry lubricant of the rope 3 and to bind oil. In this case the thickener functions as a material that stores the oil and does not form a solution with the oil.

(12) The binder agent is arranged to keep the other materials of the lubricant 8, i.e. the oil, and the thickener together better. The binder agent is e.g. an organically-based mass, such as a butyl compound or some other substance suited to the purpose, e.g. a resin-based or wax-based substance.

(13) The lubricant 8 is manufactured simply by mechanically mixing its different constituent parts with each other. The mixing ratios of the different constituents of the lubricant 8 are e.g. approx. 15-80%, preferably approx. 20-30%, oil, e.g. approx. 10-85%, preferably approx. 65-75%, thickener, and e.g. approx. 0-10%, suitably approx. 3-6%, e.g. 5%, binder agent. The aforementioned percentage figures are percentages by weight. Owing to the large amount of thickener, the structure of the lubricant 8 is paste-like. With the help of the binder agent and thickener, the lubricant 8 stays on the rope well and does not detach easily.

(14) The lubricant 8 according to the invention differs from conventional lubricating grease in that, among other things, preferably the lubricant comprises a very high proportion of thickener and less oil. The thickener can account for e.g. at most 85%, in which case the proportion of base oil remains at 15% at the highest. Instead of that, with lubricating greases the proportion of base oil in the grease is 80-90%, in which case the proportion of thickener and other substances remains only at 10-20%.

(15) FIG. 3 presents a graph compiled on the basis of the measurement results obtained in tests, of the wearing of elevator ropes lubricated in a different way. The curves p1 and p2 present ropes lubricated with paraffin according to prior art, and the curves n1 and n2 present ropes lubricated with the lubricant 8 according to the invention. The wearing of the ropes was tested with test equipment such that the rope was driven back and forth in a groove of a rope sheave and wearing of the rope was diagnosed from the reduction in diameter of the rope.

(16) It can be seen from FIG. 3 that the ropes p1 and p2 that were originally slightly over 4 mm thick and lubricated with paraffin-based lubricant have thinned after approx. one million test cycles to become 3.9 millimeters thick in their diameter. After 1.5 million test cycles, both the ropes p1 and p2 seem to have essentially lost their fitness for purpose. On the other hand, the ropes n1 and n2 that were lubricated with the lubricant 8 according to the invention have not really worn at all even during the 5 million test cycles shown in FIG. 3.

(17) FIG. 4 presents a graph, compiled on the basis of the results of measurements made in a laboratory, of the relationship between the friction factor of the rope groove of the traction sheave 4 and the slip percentage of a steel rope p1 lubricated with a paraffin-based lubricant according to prior-art and a steel rope n1 lubricated with the lubricant 8 according to the invention. The case shown here is thus the empirically obtained effective friction factor between two objects that slide against each other, and not the specific friction factor for an individual material.

(18) It can be seen from the graph that in the case of a steel rope lubricated with a paraffin-based lubricant according to prior art, which is represented by the curve p1 in FIG. 4, the effective friction factor rises linearly and relatively sharply in the initial phase of slip. When the slip is approx. 0.3%, the increase in the effective friction factor has slowed down, being in this phase now approx. 0.08. After this when the slip increases, the rise in the effective friction factor slows down even faster and does not increase over the approx. 0.1 limit here, even if the slip were to grow more. In this case, the situation is that the grip of the elevator rope in the groove of the traction sheave 4 has been lost.

(19) Correspondingly, in the case of a steel rope lubricated with the lubricant 8 according to the invention, which is represented by the curve n1 in FIG. 4, the effective friction factor again rises linearly and relatively sharply in the initial phase of slip. As the slip increases, the effective friction factor now also continues its increase, essentially linearly to a higher value of effective friction factor than with the rope represented by the curve p1. With the rope n1 lubricated with the lubricant 8 according to the invention, as the slip increases, the effective friction factor reaches a value of almost 0.14. In this case considerably more grip reserve remains for the traction sheave 4 in case of unexpected situations, and larger values than 0.1, e.g. values approaching 0.14, can be used for the effective friction factor in the dimensioning. This enables a higher ratio T.sub.CAR/T.sub.CTW of rope forces, in which case it is possible to achieve smaller moving masses, a further consequence of which is smaller acceleration forces, lower energy consumption and smaller losses. In addition, savings can be made in materials.

(20) It is clearly verified by the tests described above that, owing to the high proportion of thickener contained in the lubricant 8, the lifetime of an elevator suspension rope 3 lubricated with the lubricant 8 is considerably longer than the lifetime of elevator ropes lubricated with prior-art lubricants, and in addition the friction factor between the rope 3 and the traction sheave 4 is greater than when using conventional lubricants, which enables more advantageous dimensioning.

(21) One characteristic aspect, among others, of the elevator according to the invention is that the elevator is provided with suspension ropes 3 that are lubricated with a lubricant 8 that contains thickener, the load-bearing material of which ropes is metal, e.g. steel. The thickener in the lubricant of the suspension ropes 3 of the elevator comprises a suitable aforesaid percentage of the whole mass of the lubricant 8. In addition, the lubricant 8 can contain the aforementioned binder agents and other additives.

(22) The use of the aforementioned lubricant 8 that contains thickener for lubricating a rope laid from metal wires is further characteristic for the solution according to the invention.

(23) It is obvious to the person skilled in the art that different embodiments of the invention are not only limited to the examples described above, but that they may be varied within the scope of the claims presented below. Thus, for example, the composition of the lubricant and the mixture ratio of the different constituents can also be different to what is described above.

(24) Likewise it is obvious to the person skilled in the art that instead of synthetic oil, mineral oils or vegetable oils suited to the purpose can also be used as an oil in the lubricant.

(25) It is further obvious to the person skilled in the art that the zinc of the rope wires of a suspension rope, with which the rope wires are coated against corrosion, can also be a thickener, i.e. a necessary solid additive.