JP4523364B2 - elevator - Google Patents

Description

  The present invention relates to an elevator, and more particularly to a technique for making appropriate friction between a sheave and a rope that drives a rope on which an elevator car is suspended.

  A rope-type elevator that drives a car with a rope is to hang a rope on a sheave attached to the motor of the hoisting machine, suspend the car on one end of the rope across the sheave, and balance the car on the other end The drive device of the structure which suspended the counterweight (weight) was provided.

  Here, the counterweight has a mass that is balanced when, for example, half of the passengers get on the car, but it is rare that only half of the passenger gets on the car. Therefore, there is usually a difference between the car-side mass and the counterweight-side mass, and the mass difference is supported by the frictional force between the rope and the sheave. For example, if the masses on the car side and the counterweight side are significantly different, the frictional force between the rope and the sheave is insufficient and slipping occurs, making it impossible to operate the elevator.

  Here, assuming that the rope tension on the car side is T1 and the rope tension on the counterweight side is T2, the relationship between the two uses the friction coefficient μ between the rope and the sheave and the winding angle θ of the rope to the sheave (1 ) That is, since the difference between the tensions T1 and T2 is supported by the friction between the rope and the sheave, the friction coefficient between the rope and the sheave is preferably higher.

e ^μθ = T1 / T2 (1)
On the other hand, the elevator has a configuration in which a brake is automatically operated to stop safely in an emergency such as a power failure. When such a brake is applied, it is necessary to reduce the impact applied to the passengers in the car, and it is preferable that the rope and sheave slide when the deceleration by the brake is strong. For that purpose, the coefficient of friction between the rope and the sheave should be low.

  As described above, the friction coefficient between the rope and the sheave is preferably high in order to support the mass difference between the car and the counterweight, while it is desirable that the coefficient of friction be low considering an emergency stop. Is preferred.

  Further, if the tensions T1 and T2 are different, the rope expands and contracts due to the tension change when the rope passes through the sheave. When the rope expands and contracts while passing through the sheave, a minute slip occurs between the sheave and the rope and sheave wear. In a general elevator, a steel wire rope obtained by further twisting a strand structure obtained by twisting steel strands is used, and cast iron is used for a sheave. Moreover, what twisted the hemp core which impregnated rope grease in the center of a steel wire rope is also used. In this case, both the rope and the sheave are metal, and the rope grease exudes to the friction surface between the rope and the sheave, so that the wear between the rope and the sheave is small. Further, in order to increase the surface pressure between the rope and the sheave and increase the frictional force, the sheave groove processed into a V-groove or the like is used.

  On the other hand, Patent Document 1 discloses a resin-coated rope in which a steel wire rope formed by twisting steel strands is covered with a resin. In the case of such a resin-coated rope, since the outside of the steel wire rope is coated with a resin, the friction between the sheave and the metal becomes a resin. In particular, when rope grease is not used in consideration of prevention of resin deterioration, the friction coefficient increases because the resin of the resin-coated rope and the metal of the sheave rub in a dry state. When the coefficient of friction is high, wear tends to occur, the wear of the coating resin increases, and the coating of the resin-coated rope is likely to be damaged.

  In addition, in elevator installation work, etc., there is an operation of carrying a hoisting machine, a car, a counterweight, etc. into the hoistway, and then attaching the rope to the car weight and the car through the pulley one by one. In this work, if the friction coefficient between the rope and the pulley is high, it becomes difficult to pass the pulley, and extra work is required.

  Patent Document 2 discloses an elevator tension member in which a load transmission cord is coated with a resin, and discloses that a polyurethane lining is provided on a sheave in order to reduce damage to the elevator tension member. . As a method for reducing the friction coefficient, Patent Document 3 discloses a method for reducing a friction coefficient between fibers in a rope using a fiber made by impregnating a resin fiber rope with a fluororesin.

JP 2001-262482 A Special Table 2002-505240 JP 11-293574 A

  As described above, it is desirable that the coefficient of friction between the elevator rope and the sheave be in a certain appropriate range. In this regard, in the case of a conventional steel wire rope in which a strand of conventional steel is twisted and a hemp core impregnated with rope grease in the center is twisted, the coefficient of friction between the metal sheave and the appropriate range It is possible to fit in.

  However, when a resin-coated rope is used, the friction coefficient between the metal sheave and the metal becomes a friction between the resin and the metal, so the friction coefficient is remarkably high and the impact applied to the car during an emergency stop increases. There's a problem. Further, since the resin is easily worn when the coefficient of friction is high, the coating may be damaged due to aging.

  In order to avoid such damage, it is conceivable to reduce the coefficient of friction with the sheave by impregnating the coating resin of the resin-coated rope with a fluororesin. It is not practical to coat the rope used above with a fluororesin from the viewpoint of cost increase.

  Such a problem of friction between the resin-coated rope and the sheave has a similar problem in friction between a pulley and a resin-coated rope that are used by appropriately laying the rope.

  An object of the present invention is to reduce damage to a resin-coated rope in an elevator using a resin-coated rope and to reduce an impact applied to a car during an emergency stop or the like.

In order to solve the above-mentioned problems, the present invention provides a sieve when a resin-coated rope formed by coating the outer periphery of a steel wire rope obtained by further twisting a strand structure in which steel strands are bundled with urethane resin is used. The pulley is characterized in that an elevator is formed using at least a nickel layer containing a fluororesin on the contact surface with the rope.

  That is, the present invention uses a fluororesin having a low friction coefficient to reduce the friction coefficient between the sheave and / or the pulley and the resin-coated rope, and the sheave having a surface area much smaller than that of the rope when viewed from the whole elevator. Alternatively, by using a fluororesin on the contact surface of the pulley with the rope, it is possible to put it to practical use while suppressing an increase in cost.

  In particular, the main purpose is to obtain a stable coefficient of friction by mixing a fluororesin into the nickel layer. In other words, the fluororesin can realize a low coefficient of friction because it is easily sheared due to the sliding of the band structure, which is a specific fine structure, but at the same time it has a lot of wear, so the life of the fluororesin layer alone is short. Therefore, a stable friction coefficient cannot be maintained. Therefore, a stable friction coefficient is obtained by mixing a fluorine resin into a plating layer such as nickel. As a result, the coefficient of friction between the sheave and / or the pulley can be within a preferable range, and the damage to the resin-covered rope of the elevator can be reduced and the impact applied to the car during an emergency stop can be reduced. it can. In addition, as a fluororesin to mix, tetrafluoroethylene (PTFE: Teflon (trademark)) is especially preferable.

  In the above case, it is preferable to form a groove on which the rope is applied to the sheave or the pulley, and to form a semicircular cross section of the groove. According to this, the resin-coated rope can be accommodated in the groove, and the resin-coated rope and the groove can be adapted by initial wear, and a more stable friction coefficient with little change with time can be realized. In particular, the circular cross section of the groove is preferably equal to or slightly larger than the outer diameter of the resin-coated rope.

  Moreover, the nickel layer containing a fluororesin can be formed by immersing the sheave or pulley in a nickel plating solution containing 10 to 30 vol% of tetrafluoroethylene powder.

  Furthermore, the present invention can solve the above-mentioned problems by forming irregular fine irregularities on at least the contact surface of the sheave or pulley with the rope instead of the nickel layer containing the fluororesin.

That is, due to irregular and fine irregularities, an air pocket is formed on the contact surface with the rope of the sheave or pulley, and the friction coefficient can be reduced by the air pool. Such irregular and fine irregularities can be formed by, for example, shot peening treatment, in which fine particles collide with a contact surface with a rope of a sheave or a pulley at high speed. According to this method, since a very thin layer can be work-hardened, the hardness of the contact surface can be increased without impairing the toughness of the entire sheave or pulley, and the fatigue life can be extended. In addition, fine particles such as ceramic, metal, and glass can be used as the fine particles. The surface roughness is preferably Ra 1.3 to 1.5 (Rmax 12.0 to 15.0).

  According to the present invention, the coefficient of friction between the resin-coated rope and the sheave and / or pulley can be set within a preferable range, and the resin-coated rope of the elevator can be reduced in damage and can be applied to the car during an emergency stop or the like. The applied impact can be reduced.

  Hereinafter, the present invention will be described based on embodiments.

(Embodiment 1)
FIG. 1 shows one embodiment of a sheave which is a characteristic part of the present invention, and FIG. 2 shows a conceptual configuration diagram of a main part of an elevator drive device according to one embodiment using the sheave in FIG. As shown in FIG. 1, a passenger car 1 on which a passenger is placed is connected to one end of a rope 2, the rope 2 is wound around a sheave 4 that is rotationally driven by a driving device 3, and the other end of the rope 2 is connected via a pulley 5. It is connected to the counterweight 6. By rotating the sheave 4 by the driving device 3, the car 1 moves up and down in a hoistway (not shown).

  The sheave 4 of the present embodiment is formed as shown in FIG. FIG. 1A is a front view of the sheave 4, and FIG. 1B is a cross-sectional view of the sheave 4 taken along line 1b-1b. As shown in FIG. 1B, a plurality (three in the illustrated example) of grooves 15 are provided on the outer peripheral surface of the sheave 4, and the cross section of the grooves 15 is formed in a semicircular shape. In particular, at least an inner surface of the groove 15 is provided with a fluororesin-containing nickel layer 16 formed by applying a fluororesin-containing nickel plating process. The nickel layer 16 can be formed by immersing a sieve in a nickel plating solution in which fluororesin powder is mixed. Note that the base material of the sheave 4 is cast iron such as FC250, for example.

  Moreover, the rope 2 of this embodiment has the coating resin 11 on the outer periphery of the steel wire rope in which the strand structure in which the steel strands 7 are bundled is further twisted as shown in the sectional view of FIG. A formed resin-coated rope is used. As the coating resin 11, for example, as described in Patent Document 1, a urethane resin can be used. As shown in the figure, the resin-coated rope 2 is hung in the groove 15 of the sheave 4 and the resin coating 11 is easily worn, so the shape of the groove 15 of the sheave 4 is semicircular according to the outer diameter of the rope 2. The contact surface pressure with the rope 2 is made low.

  Thus, according to the embodiment of FIG. 1, since the inner surface of the groove 15 of the sheave 4 in contact with the rope 2 having a resin coating has the nickel layer 16 mixed with the fluororesin, While suppressing wear, the friction coefficient between the rope 2 and the sheave 4 can be stably maintained within an appropriate range. As a result, wear of the resin coating on the rope 2 can be suppressed.

  In particular, since the fluororesin is mixed in the plating layer such as nickel, the wear of the fluororesin that is easily worn can be suppressed by the nickel layer, so that a stable friction coefficient can be maintained. Moreover, the friction coefficient between the rope 2 and the sheave 4 can be set within a preferable range. As a result, damage to the resin-coated rope of the elevator can be reduced, and the impact applied to the car during an emergency stop or the like can be reduced.

  Moreover, since the surface area of the sheave 4 is much smaller than that of the rope 2 when viewed from the whole elevator, even if an expensive fluororesin such as tetrafluoroethylene is used for the contact surface of the sheave 4, the resin coating of the rope 2 Compared with the case where is made of tetrafluoroethylene, it can be put into practical use while suppressing an increase in cost.

  Here, in the sheave 4 of Example 1 of the present embodiment, the sheave body is formed of cast iron (FC250), and the nickel layer 16 is formed by mixing ethylene tetrafluoride as a fluororesin. That is, the nickel layer 16 was formed by immersing the sieve in a nickel plating solution mixed with tetrafluoroethylene powder. Since this tetrafluoroethylene is easily sheared by sliding the specific fine structure of the band structure to each other, the friction coefficient of the surface of the groove 15 can be lowered.

(Embodiment 2)
FIG. 4 shows another embodiment of the sheave 4 according to the present invention. 4A is a front view of the sheave 4, and FIG. 4B is a cross-sectional view taken along line 4b-4b of FIG. 4A. This embodiment is different from the embodiment of FIG. 1 in that irregular and fine irregularities 17 are formed instead of the nickel tetrafluoride-containing nickel layer 16 on the inner surface of the groove 15. Such irregular fine irregularities can be formed, for example, by shot peening, for example, by causing fine particles to collide with the inner surface of the groove 15 which is a contact surface with the rope 2 of the sheave 4 at a high speed. According to this method, since a very thin layer can be work-hardened, the hardness of the contact surface can be increased without impairing the toughness of the entire sheave, and the fatigue life can be extended. In addition, fine particles such as ceramic, metal, and glass can be used as the fine particles.

Here, in the sheave 4 of Example 2 of the present embodiment, the sheave body is formed of cast iron (FC250), and a shot peening process is performed in which fine particles collide with the inner surface of the groove 15 at a high speed, and the irregular and fine Unevenness 17 was formed.
(Discussion)
Here, the result of actually measuring the friction coefficient between the sheave 4 and the rope 2 of Examples 1 and 2 will be described with reference to FIGS. FIG. 5 shows the configuration of the traction evaluation apparatus used in the evaluation test of the friction coefficient between the rope 2 and the sheave 4 in this embodiment. FIG. 6 shows a configuration of Comparative Example 1 in which a conventional steel wire rope 9 is applied to a conventional sheave 10. The steel wire rope 9 of Comparative Example 1 is obtained by twisting steel strands 7 and twisting a hemp core 8 impregnated with rope grease at the center, and the sheave 10 is cast iron of FCD700 having good wear resistance. Is formed with a V-shaped groove 11. Thereby, the contact surface pressure of the steel wire rope 9 and the sheave 10 is increased, and the frictional force is increased. Since the surface pressure is high, the sheave 10 is likely to be worn, but since the rope grease impregnated in the hemp core 8 oozes out, wear is minimized.

  As shown in FIG. 5, the traction evaluation apparatus includes a motor 12 that rotationally drives the sheaves 4 and 10, a dead weight 13 that loads the ropes 2 and 9, and a load cell 14 that measures the rope tension via the sheave. Is done. One ends of the ropes 2 and 9 are connected to the dead weight 13 and are wound around the sheaves 4 and 10 at an angle of 180 degrees. A load cell 14 is connected to the other ends of the ropes 2 and 9.

  In the measurement of the friction coefficient using this traction evaluation apparatus, first, a dead weight 13 having a constant mass is suspended from the ropes 2 and 9, and the sheaves 4 and 10 are slowly rotated by the motor 12. The change in tension of the ropes 2 and 9 at that time is measured by the load cell 14, and the tension when the ropes 2 and 9 and the sheaves 4 and 10 clearly start to slide is recorded. For example, when the sheaves 4 and 10 are rotated counterclockwise, the tension measured by the load cell 14 at this time is T1, the mass of the dead weight 13 is T2, the winding angle of the ropes 2 and 9 on the sheaves 4 and 10 is The friction coefficient is calculated by formula (1) with 180 degrees.

  An example of the measurement result of the friction coefficient is shown in FIG. The conditions of Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1.

  The friction coefficient shown in FIG. 7 is shown as a relative value with the friction coefficient of the first comparative example 1 of the number of tests taken as 1. The figure shows the number of tests and the coefficient of friction, and the coefficient of friction was measured several times using the same rope and sheave.

  As can be seen from FIG. 7, the friction coefficient of the resin-coated rope of Comparative Example 2 and the sheave without surface treatment is more than twice the friction coefficient of the steel wire rope of Comparative Example 1 and the sheave without surface treatment. Moreover, it was found that the friction coefficient of Comparative Example 2 tends to increase with the number of tests. When the friction coefficient is high in this way, when the deceleration due to the brake is strong due to the emergency stop of the car due to the brake at the time of a power failure, the rope and the sheave do not slip, and a large impact is applied to the passenger.

  On the other hand, the friction coefficient of Example 1 is almost the same as that of Comparative Example 1, and is stable regardless of the number of tests. Further, the friction coefficient of Example 2 is almost the same as that of Comparative Example 1, and is stable regardless of the number of tests. Thus, by applying a surface treatment to the sheave, the friction coefficient can be reduced and stabilized.

  Next, FIG. 8 shows the results of measuring the friction coefficients of Examples 1a, 1b, and 1c in which the content of tetrafluoroethylene in Example 1 was changed in comparison with Comparative Example 1. The test method and the relative friction coefficient are the same as those in FIG. From this figure, it can be seen that the friction coefficient increases as the amount of ethylene tetrafluoride in the plating layer 16 decreases. Tetrafluoroethylene (PTFE) is effective in reducing the coefficient of friction because it is easily sheared due to the sliding of specific band structures. However, since it is soft, it is easy to wear and is often mixed with plating. Even in the case of mixing with plating, if the content is increased, the plating is easily peeled off. Therefore, the content of ethylene tetrafluoride in the plating is preferably within 30% by volume. Since the friction coefficient differs by changing the content of tetrafluoroethylene, it is possible to control the friction coefficient between the resin-coated rope and the sheave by nickel plating treatment with tetrafluoroethylene. In addition, since the resin-coated rope does not use grease from the viewpoint of preventing deterioration, there is a possibility that the groove of the sheave is corroded, but there is also an effect of preventing the corrosion by nickel plating with tetrafluoroethylene.

  Next, the friction coefficient of Example 2 will be examined. As described above, the friction coefficient is adjusted to an appropriate range for the resin-coated rope from the actual measurement results of FIG. I found out that Here, the effect of reducing the friction coefficient of the unevenness 17 will be examined.

  FIG. 9 is a perspective view showing the result of measuring the surface shape of the irregularities 17 subjected to the particle collision treatment with a non-contact type surface roughness meter. FIG. 9A shows the surface shape of the irregularities 17 of Example 2a in which the fine particles were subjected to powerful and powerful collision treatment. FIG. 9B shows the irregularities of Example 2b in which the fine particles were subjected to collision treatment with a weaker force. 17 examples. For comparison, FIG. 5C shows a measurement result of the surface shape of the inner surface of the groove 15 before the fine particle collision treatment, that is, without the fine particle collision treatment. From these figures, it can be seen that the machining marks by the lathe are regularly left on the inner surface of the groove 15 of FIG. On the other hand, when the fine particle collision treatment shown in FIGS. 9A and 9B is performed, it can be seen that irregular and fine irregularities are formed on the surface. Each surface roughness Ra (JIS standard) is Ra 2.17 μm (Rmax 16.40 μm) in the case of FIG. 9C without the fine particle collision treatment, and Ra 1.30 μm in the case of the fine particle collision strong treatment in FIG. 9A. (Rmax 12.40 μm), Ra in the case of the fine particle collision weak treatment in FIG. 9B was 1.42 μm (Rmax 14.57 μm). That is, the surface roughness is smaller when the fine particle collision treatment is performed than when the fine particle collision treatment is not performed.

  Here, the example which measured the relationship between surface roughness and a friction coefficient is shown in FIG. This figure shows the surface roughness Ra μm on the horizontal axis and the relative surface friction coefficient on the vertical axis. Here, the relative surface friction coefficient is a relative value with a value of 1 when the surface roughness is Ra 3.2 μm. The surface roughness Ra of the sample was adjusted by changing the lathe processing speed and polishing. It can be seen from the figure that the friction coefficient tends to increase when the surface roughness is small.

  However, as shown in FIG. 7, it was confirmed by experiments that the friction coefficient is reduced by the fine particle collision treatment, although the surface roughness is lowered. This is thought to be because the surface shape is not regular irregularities as processed by a lathe, but irregular irregularities due to collision of fine particles. In other words, it can be considered that an air pocket is formed on the contact surface between the sheave 4 and the rope 2 due to the irregular fine irregularities, and the friction coefficient is reduced by the air pool.

  Next, FIG. 11 shows the measurement results of the friction coefficient obtained by changing the strength of the fine particle collision to determine the influence of the irregular surface roughness of Example 2 on the friction coefficient. This figure shows the measurement results of the friction coefficients of Examples 2a and 2b shown in FIG. The test method and the relative friction coefficient are the same as those in FIG. From this figure, it can be seen that the friction coefficient of Example 2b of the fine particle collision weak treatment is low.

  From the above, as in Embodiment 2, there are irregularities 17 on the inner surface of the groove 15 and the surface roughness Ra1.3 to 1.5 (Rmax 12.0 to 15.0). It can be said that it is desirable to reduce the friction coefficient. Further, since the unevenness of the surface can be changed by the strength of the fine particle collision, the friction coefficient between the resin-coated rope and the sheave can be controlled by the fine particle collision treatment.

It is a block diagram of the sheave of one embodiment of the present invention. It is a schematic block diagram of the elevator drive device which concerns on this invention. It is sectional drawing of the resin-coated rope of one embodiment of this invention. It is a block diagram of the sheave of other embodiment of this invention. It is a schematic block diagram of the traction evaluation apparatus used for the measurement of the friction coefficient of a rope and a sheave. It is a cross-sectional block diagram of the contact part of the conventional steel wire rope and sheave of a comparative example. It is a figure which shows the measurement result example of the friction coefficient of the combination of the rope and sheave of Example 1, 2 of this invention in contrast with Comparative Example 1,2. It is a figure which shows the measurement result example of the friction coefficient by the difference in ethylene tetrafluoride content of Example 1 of this invention in contrast with the comparative example 1. FIG. It is a figure which shows the measurement result example of the surface roughness at the time of changing the fine particle collision intensity | strength of the sheave of Example 2 of this invention in contrast with the measurement result of the surface roughness without fine particle collision treatment. It is a figure which shows the measurement result of the friction coefficient which changed the surface roughness of the sieve without fine particle collision treatment. It is a figure which shows the measurement result example of a friction coefficient at the time of changing the fine particle impact strength of the sieve of Example 2 of this invention in contrast with the comparative example 1.

Explanation of symbols

1 Car 2 Rope 3 Drive device 4 Sheave 5 Pulley 6 Counterweight 15 Groove 16 Nickel layer 17 Concavity and convexity

Claims (1)

In an elevator comprising an iron sheave that is rotationally driven by a hoist, a rope hung on the sheave, a ride hung on one end of the rope, and a weight hung on the other end of the rope ,
The rope is formed by coating urethane resin on the outer periphery of a steel wire rope obtained by twisting a strand structure in which steel strands are bundled,
Forming a fluororesin-containing nickel layer on at least the surface of the sheave in contact with the rope, the fluororesin-containing nickel layer in a nickel plating solution formed by mixing 10-30 vol% of tetrafluoroethylene powder. An elevator formed by immersing the sheave.

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