JP2019048698A - Elevator rope - Google Patents

Abstract

To provide an elevator rope that enables reduction of the changing amount of rope elongation caused by fluctuation of rope tension at the time of elevator boarding/alighting even when a rope rupture strength is increased to reduce the number of ropes.SOLUTION: This elevator rope is formed by twisting a plurality of strands which are formed by standing a plurality of copper wires, in which the ratio a of Pto d, the ratio b of Pto d, and the rupture strength T(N) of the elevator rope satisfy the following expression A, where d(mm) denotes the diameter of the elevator rope, Pdenotes a rope pitch which is a strand winding interval, and Pis a strand pitch which is a copper wire winding interval.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an elevator rope.

  Generally, an elevator car is suspended by a wire rope (hereinafter referred to as “rope” or “elevator rope”), and this rope is wound around a driving sheave of a hoisting machine, and a rope groove and a rope on the surface of the sheave. The car is moved up and down by driving with friction.

  By the way, for example, in a machine room-less elevator in which a hoisting machine is installed in a hoistway, downsizing of the hoisting machine is required in order to reduce the cross-sectional area of the hoistway. As a means for realizing this, there is a thin driving sheave. By reducing the thickness of the drive sheave, the axial length of the hoisting machine can be shortened, and the hoisting machine can be reduced in size. For this reason, as an elevator rope, there is a demand for a high-strength rope that has a high breaking strength per one and can reduce the number of ropes required to suspend the car.

As a configuration for increasing the strength of a rope, for example, Patent Document 1 discloses an IWRC having a core strand, a plurality of side strands arranged around the core strand, and a coating resin that covers the core strand and the plurality of side strands. (Independent Wire Rope Core), a plurality of main strands arranged around the IWRC,
In the main rope for elevators, the plurality of side strands are arranged at substantially equal intervals on the circumference of the virtual layer center circle where the centers of the plurality of side strands are located. A main rope for an elevator is disclosed, wherein a total ratio of gaps between two side strands adjacent to each other in the circumferential direction of the virtual layer center circle among the plurality of side strands is 8.5% or more. .

  The rope disclosed in Patent Document 1 is formed by drawing a wire constituting the rope into a thin wire, and has a breaking strength of 2300 MPa (the strand breaking strength of a generally popular rope for elevators is about 1620). Wires that have been increased to a grade of ˜1910 MPa) are used. The rope strength is improved in proportion to the strand strength, and the number of ropes can be reduced.

International Publication No. 2016/199204

  The number of ropes used for an elevator is determined by the ratio of the load per rope and the breaking strength, and the number of ropes used per elevator is reduced by improving the breaking strength per piece. can do. One method for improving the breaking strength of a wire rope is to improve the breaking strength per strand constituting the wire rope, but the elastic modulus per strand is not proportional to the breaking strength. The rigidity of the entire rope is reduced by the amount that the number of ropes is reduced. For this reason, for example, when the load applied to the rope suddenly changes due to getting on and off of the elevator, the amount of expansion and contraction of the rope becomes large, and the riding comfort is lowered.

  In order to prevent this, the elevator rope is required to have a characteristic that it is difficult to stretch even if tension is applied. However, in Patent Document 1, attention is focused on the improvement of the rope life by mainly suppressing the contact between the high-strength strands, and the rope elongation is not considered.

  In view of the above circumstances, an object of the present invention is to provide an elevator rope that can reduce the amount of change in rope elongation that occurs when rope tension fluctuates due to getting on and off the elevator even if the breaking strength of the rope is improved and the number of ropes is reduced. Is to provide.

In order to achieve the above object, the present invention provides an elevator rope formed by twisting a plurality of strands formed by twisting a plurality of steel wires, wherein the diameter of the elevator rope is d (mm), and the winding interval of the strands is the rope pitch. P ₁ , when the winding interval of the steel wire is the strand pitch P ₂ , the ratio a of P ₁ to d, the ratio b of P _{2 to} d, and the breaking strength T (N) of the elevator rope satisfy the following formula A: An elevator rope is provided.

  In the above formula, E: longitudinal elastic modulus (MPa) of the material used for the elevator rope, G: transverse elastic modulus (MPa) of the material used for the elevator rope, and N: the number of strands.

In order to achieve the above object, the present invention provides an elevator rope formed by twisting a plurality of strands formed by twisting a plurality of steel wires. The steel wire is formed by twisting a plurality of strands. When the diameter of the elevator rope is d (mm), the winding interval of the strand is the rope pitch P ₁ , and the winding interval of the steel wire is the strand pitch P ₂ , the ratio of P _{1 to} d with respect to the ratios a and d the ratio of P ₂ b and elevators breaking strength of the rope T (N) provides a lift rope, characterized by satisfying the above expression a.

  More specific configurations of the present invention are described in the claims.

  According to the present invention, there is provided an elevator wire rope that can reduce the amount of change in rope elongation caused by fluctuations in rope tension due to elevator getting on and off even when the rope breaking strength is improved and the number of ropes is reduced. be able to.

  Problems, configurations, and effects other than those described above will become apparent from the following description of embodiments.

The side view which shows the 1st example of the elevator rope of this invention typically. The side view which shows the 2nd example of the elevator rope of this invention typically. It is a figure which shows the relationship of tension | tensile_strength T, elongation (delta) Lτ, and (delta) Lρ in an elevator rope. The cross-sectional schematic diagram of the elevator rope by which the outermost layer of an elevator rope is comprised by ten strands. The cross-sectional schematic diagram of the elevator rope by which the outermost layer of an elevator rope is comprised by six strands. It is a cross-sectional schematic diagram of the elevator rope in which the outermost layer of the strand is composed of six steel wires. It is a cross-sectional schematic diagram of the elevator rope in which the outermost layer of the strand is composed of 12 steel wires. It is a cross-sectional schematic diagram of the elevator rope (tertiary twist) which has the steel wire by which the strand was twisted. It is a graph which shows the relationship of the strand pitch multiple at the time of rope strain amount: 0.55%, and a rope pitch multiple. It is a side view which shows typically the elevator rope produced for the test. It is a graph showing the relationship between the elongation amount [delta] L ₁ and rope pitch P ₁ and strand pitch P ₂ of the rope.

  Hereinafter, an embodiment of an elevator wire rope according to the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a side view schematically showing a first example of an elevator rope according to the present invention. As shown in FIG. 1, the elevator rope 1 is formed by twisting a plurality of strands 2 in which a plurality of steel wires 3 are twisted together. In FIG. 1, only one strand 2 and one steel wire 3 are illustrated in consideration of the visibility of the drawing.

  Although not shown in FIG. 1 at the center of the elevator 1, a core (fiber core, steel wire core or the like) is disposed, and the strand 2 is twisted on the core. The plurality of strands 2 are arranged with substantially uniform gaps on the same circumference. The same applies to the steel wire 3. In addition, the strand 2 and the steel wire 3 are each arranged in the radial direction in one layer, in addition to the two-layer arrangement in which the two layers are arranged on the circumference, and the three layers in the circumference. Some are composed of a plurality of layers, such as a layer arrangement.

In the present invention, spacing the strands 2 of one constituting the elevator rope is around the (winding gap) and rope pitch P _1, spacing steel wire 3 constituting the strands 2 makes one rotation (winding gap) the strand pitch P ₂ And In other words, the rope pitch P ₁ is a length until the strand 2 goes around the core, and the strand pitch P ₂ is a length until the steel wire 3 goes around the central axis of the strand. It is.

FIG. 2 is a side view schematically showing a second example of the elevator rope of the present invention. In FIG. 2, the steel wire 3 shows what was formed by twisting a plurality of strands 3a. The present invention can also be applied to an elevator rope having such a configuration. Spacing wires 3a constituting the steel wire 3 makes one rotation (the winding interval) and steel wire pitch P _3.

  Next, the mechanism of the elevator rope elongation will be described with reference to FIG. FIG. 3 is a diagram showing the relationship between the tension T and the elongations δLτ and δLρ in the elevator rope. Consider a case where a tension T acts on the twisted strand in the axial direction of the central axis 30 of the twist. The elongation of the strand 2 at this time is the tensile force acting in the axial direction of the shaft 31 extending in the perpendicular direction of the cross section of the strand 2 and the elongation δLτ generated by the shearing force acting on the cross section of the strand 2 and the twist. It is given by the sum of the elongation δLρ due to the occurrence of minute strain in the strand 2 itself (the twisted central axis 30 and the axis 31 perpendicular to the strand cross section are at an angle of θ °).

Thus, the elevator rope length L _1, elongation [delta] L ₁ when the tension T ₁ is acted in the direction of the central axis of twisting of the strands, can be expressed as the following equation (1). Similarly, the elongation δL ₂ when the tension T ₂ acts in the direction of the central axis of the twist of the steel wire 3 having the length L ₂ can be expressed as the following formula (2), and the strand 3a having the length L ₃ The elongation δL ₃ when the tension T ₃ acts in the direction of the central axis of the twist can be expressed as the following formula (3).

δL ₁ = δL ₁ τ + δL ₁ ρ Equation (1)
δL ₂ = δL ₂ τ + δL ₂ ρ Equation (2)
δL ₃ = δL ₃ τ + δL ₃ ρ Equation (3)
However, L ₁ is the direction of the central axis of the twist of the strand length (mm), L ₂ is the length of the central axis of twisting the steel wire (mm), L ₃ is the direction of the central axis of the twist of the strand length (Mm).

In the strand formed by twisting a plurality of steel wires, since the vertical direction of the strand cross section and the central axis direction of the steel wire twist are the same direction, the tensile force acting in the vertical direction of the strand cross section is The force acts in the direction of the central axis of the twist of the steel wire. Therefore, it is considered that the elongation δL ₁ ρ due to the tensile force of the strand is equal to the elongation δL ₂ of the entire steel wire. This relationship is the same for steel wires formed by twisting a plurality of strands. When the above-described relationship is summarized, a secondary twisted rope (a rope in which the strand and the steel wire in FIG. 2 are twisted). The elongation of the tertiary twisted rope (the rope in which the strand, the steel wire, and the strand of FIG. 3 are twisted) can be expressed as in Equation (5).

δL ₁ = δL ₁ τ + δL ₂ τ + δL ₂ ρ Equation (4)
δL ₁ = δL ₁ τ + δL ₂ τ + δL ₃ τ + δL ₃ ρ Equation (5)
Regarding the expressions (4) and (5), the elongation δL ₁ τ when the tension T ₁ is applied in the direction of the central axis of the strand of the strand having the length L ₁ is expressed by the following equation, where K ₁ τ is the spring constant of the strand. obtained in (6), _{K 1} τ can be expressed as the following equation (7). For example, the same formula can be seen when obtaining the spring constant of a coil spring.

δL ₁ τ = T ₁ / K ₁ τ Equation (6)
K ₁ τ = 0.03 × G × S ₁ / n ₁ / d ₀ formula (7)
Here, G is the transverse elastic modulus (MPa) of the strand, S ₁ is the cross-sectional area (mm ² ) per strand, n ₁ is the number of strand twists (pieces) per length L ₁ , and d ₀ is the rope diameter (Mm).

Similarly, the elongation δL ₂ τ when the tension T ₂ is applied in the direction of the central axis of the twist of the steel wire of length L ₂ is obtained by the following equation (8), where K ₂ τ is the spring constant of the steel wire. K ₂ τ can be expressed as the following equation (9). Further, the elongation δL ₃ τ when the tension T ₃ is applied in the direction of the central axis of the strand of the length L ₃ is obtained by the following equation (10), where K ₃ τ is the spring constant of the strand. , K ₃ τ can be expressed as the following equation (11). However, in the case of strands, there are geometric constraints only in one axial direction (up and down direction), but in the case of steel wires, since it is further twisted, it is geometric in three axis directions (up and down, front and rear, left and right in all directions). Get restrained. Therefore, since the spring constant of the steel wire increases as the twisting order increases, it is multiplied by a restraint factor.

δL ₂ τ = T ₂ / K ₂ τ Formula (8)
K ₂ τ = 0.03 × α × G × S ₂ / n ₂ / d ₀ formula (9)
Here, S ₂ is a cross-sectional area (mm ² ) per steel wire, n ₂ is the number of strands (pieces) of the steel wire per length L ₂ , and α is a constraint coefficient (α = 10).

δL ₃ τ = T ₃ / K ₃ τ Equation (10)
K ₃ τ = 0.03 × α ² × G × S ₃ / n ₃ / d ₀ formula (11)
Here, S ₃ is the cross-sectional area (mm ² ) per strand, n ₃ is the number of strands (number) of strands per length L ₃ , and α is a constraint coefficient (α = 10).

The number of twists strand steel wire-strand is a value determined by the rope pitch P _1-strand pitch P ₂ · steel wire pitch P _3, the ratio of rope pitch against the rope diameter d ₀ a (P ₁ / If d ₀ ), the strand pitch ratio is b (P ₂ / d ₀ ), and the steel wire pitch ratio is c (P ₃ / d ₀ ), they can be expressed as equations (12) to (14).

n ₁ = L ₁ / (d ₀ × a) Formula (12)
n ₂ = L ₂ / (d ₀ × b) Formula (13)
n ₃ = L ₃ / (d ₀ × c) Formula (14)
Next, the relationship between the rope cross-sectional structure, the strand diameter, the steel wire diameter, and the strand diameter, and the strand twist diameter, the steel wire twist diameter, and the strand twist diameter will be described with reference to FIGS. . FIG. 4 is a schematic cross-sectional view of an elevator rope in which the outermost layer of the elevator rope is composed of 10 strands, and FIG. 5 is a sectional view of the elevator rope in which the outermost layer of the elevator rope is composed of six strands. 4 and 5, the number of steel wires in the outermost layer of the strand is nine. FIG. 6 is a schematic cross-sectional view of an elevator rope in which the outermost layer of the strand is composed of six steel wires, and FIG. 7 is a sectional view of the elevator rope in which the outermost layer of the strand is composed of 12 steel wires. In FIG.6 and FIG.7, the number of the strands of the outermost layer of an elevator rope is eight. FIG. 8 is a schematic cross-sectional view of an elevator rope (tertiary twist) having a steel wire in which strands are twisted.

As shown in FIGS. 4 to 8, the strands, the steel wires, and the strands are arranged substantially evenly on the circumference. Accordingly, the strand diameter: d ₁ , the steel wire diameter: d ₂ , the strand diameter: d _{3, the} strand twist diameter: D ₁ , the steel wire twist diameter: D ₂ and the strand twist diameter D ₃ are geometrical. And the following equations (15) to (17) are established.

d ₁ = d ₀ × sin (π / N ₁ ) / (1 + sin (π / N ₁ ))
D ₁ = d ₀ −d ₁ formula (15)
Here, N ₁ is the number of outermost strands (lines).

d ₂ = d ₁ × sin (π / N ₂ ) / (1 + sin (π / N ₂ ))
D ₂ = d ₁ -d ₂ formula (16)
Here, N ₂ is the outermost layer steel wire number (present).

d ₃ = d ₂ × sin (π / N ₃ ) / (1 + sin (π / N ₃ ))
D ₃ = d ₂ −d ₃ formula (17)
Here, N ₃ is the number of outermost strands (lines).

Next, the tension acting on the outermost strand, the outermost steel wire, and the outermost strand when the tension T ₀ acts on the rope is determined. These are determined by the ratio of the cross-sectional areas of strands, steel wires, and strands, and can be obtained geometrically. T ₁ the tension on the outermost _strand tension T ₂ in accordance with the outermost steel _wire, when the tension T ₃ according to the outermost layer strands, the following (18) wherein can be expressed as - (20) is there.

T ₁ = T ₀ / N ₁ formula (18)
T ₂ = T ₁ × (S ₂ / S ₁ ) Formula (19)
T ₃ = T ₂ × (S ₃ / S ₂ ) Formula (20)
Next, the relationship between the strands, steel wires, and strands will be described. Twist angle, rope pitch P ₁ · strand pitch P ₂ · steel wire pitch P ₃ and the twist diameter of the strand, the steel wire twisted diameter, Sadamari by twisting diameter of the wire, the following equation (21) - (23) It can be expressed as follows.

θ ₁ = tan ⁻¹ (D ₁ × π / (d ₀ × a)) Equation (21)
θ ₂ = tan ⁻¹ (D ₂ × π / (d ₀ × b)) Equation (22)
θ ₃ = tan ⁻¹ (D ₃ × π / (d ₀ × c)) Equation (23)
Here, θ ₁ represents the strand twist angle (rad), θ ₂ represents the steel wire twist angle (rad), and θ ₃ represents the strand twist angle (rad).

Moreover, the length of a strand, a steel wire, and a strand can be calculated | required using each twist angle. In a strand formed by twisting a plurality of steel wires, the spiral length of the twisted strand (the length when the strand is stretched) is equal to the length of the steel wire twist in the central axis direction. . Similarly, in a steel wire configured by twisting a plurality of strands, the spiral length of the twisted steel wire (the length when the steel wire is stretched) and the direction of the central axis of the strand of the strand Are equal in length. Therefore, the relationship between the length of the strand in the central axis direction: L ₁ , the length of the steel wire in the central axis direction: L ₂ , and the length of the strand in the central axis direction: L ₃ is expressed by the following formula (24 ) And (25).

L ₂ = L ₁ / cos θ ₁ formula (24)
L ₃ = L ₂ / cos θ ₂ formula (25)
Next, the elongation δL ₂ ρ when the tension T ₂ is applied in the direction of the central axis of the twist of the steel wire of length L ₂ is between the central axis of the steel wire twist and the vertical axis of the cross section of the steel wire. considering that is angled by twisting the steel wire, the K ₂ [rho given by: and the spring constant of the steel wire (26), expressed as K ₂ [rho following formula (27) it can.

δL _2ρ = T ₂ × cos θ ₂ / K _2ρ equation (26)
K _2ρ = E × S ₂ / (L ₂ / cos θ ₂ ) Formula (27)
Here, E is the longitudinal elastic modulus (MPa) of the steel wire.

Similarly, the elongation _{δL 3ρ} when the tension T ₃ is applied in the direction of the central axis of the strand of the length L ₃ is between the central axis of the strand of the strand and the vertical axis of the strand section. Considering that the angle due to stranding of the wire is taken, and _assuming that K _3ρ is the spring constant of the steel wire, it can be obtained by the following formula (28), and K _3ρ can be expressed as formula (29).

_{δL 3ρ} = T ₃ × cos θ ₃ / K _3ρ equation (28)
K _3ρ = E × S ₃ / (L ₃ / cos θ ₃ ) Formula (29)
Therefore, when the calculation formulas of the above formulas (1) to (29) are summarized, in the secondary twisted rope, it is composed of the number of strands: N ₁ and the number of steel wires: N ₂ , and the ratio of the rope pitch to the rope diameter: a, ratio of strand pitch: rope diameter twisted at b: d ₀ , length: elongation when a tension T ₀ acts on a rope of L ₁ : δL ₁ is expressed by the following formula (30) it can.

Similarly, in the tertiary twisted rope, it is composed of the number of strands: N ₁ , the number of steel wires: N ₂ , the number of strands: N ₃ , the ratio of the rope pitch to the rope diameter: a, the ratio of the strand pitch: b, the steel wire Pitch ratio: rope diameter twisted at c: d ₀ , length: L ₁ when stretched: T ₀ is applied to a rope of length L ₁ Elongation amount: δL ₁ can be expressed by the following formula (31).

Above Expression (30), (31) from, in tertiary twisted rope in secondary twisted rope, strands stars while the amount of strain the rope as the N ₁ increases is reduced, the number of steel wires: N _2, the number of strands : N ₃ does not affect the strain amount of the rope. This is because the cross-sectional area of the rope increases as the number of strands increases, while the cross-sectional area of the rope hardly changes even if the number of steel wires or the number of strands increases or decreases. Therefore, it is not necessary to consider the number of steel wires: N ₂ and the number of strands: N ₃ in the examination of the rope elongation.

  As for the twist pitch, as shown in the above formulas (9) and (10), the influence on the rope elongation decreases as the twist order increases, and the ratio of the steel wire pitch: the ratio of the rope pitch at c : Only 1/100 of a is affected, and becomes a very small value. Therefore, it is considered that the twist pitch of the steel wire can be ignored in the study of the rope elongation. Therefore, in the present invention, since the rope pitch ratio a and the strand pitch ratio b need only be defined, the steel wire pitch ratio c constituting the inside of the strand need not be considered.

With the above guidelines, when the rope breaking strength is improved, the burden load per rope increases, and the problem that the rope elongation (the amount of strain of the rope) increases increases with respect to the above equations (30) and (31). ) than, it is found that can reduce the amount of strain the rope by increasing the rope pitch P ₁ and strand pitch P _2.

  That is, as described above, the elongation caused by applying a load to the twisted steel wire means the elongation caused by the shearing force acting on the rope cross section and the twisting elongation, and the tensile force acting in the direction perpendicular to the cross section. It is the sum of elongation due to the occurrence of minute strain in itself. Therefore, if the pitch of each twist is lengthened, the elongation caused by the extension of the twist can be reduced and the elongation of the entire rope can be suppressed.

  In the present invention, the configuration of the elevator rope (the number of strands, steel wires, and strands) is arbitrary. Moreover, in this invention, it is not necessary to consider about the twist pitch of (outside of this invention, steel wire 3) other than the outer two (in this invention, rope 1 and the strand 2) which comprise an elevator rope. For example, in addition to the configuration shown in FIGS. 1 and 2, there is an elevator rope configuration formed by twisting a plurality of schenkels formed by twisting a plurality of strands. do it.

  On the other hand, as the rope pitch, the strand pitch, and the steel wire pitch are increased, the number of twists decreases and the twist becomes easier to unravel. In that case, the rope shape can be maintained by covering the rope with plastic or resin.

  Next, the design of the elevator rope using the above equations (30) and (31) will be described. In an elevator, when the amount of strain of the rope increases, not only the ride comfort but also the risk of tripping over the steps when entering the car is likely to occur. However, if the floor-to-floor movement becomes too large, there is a risk of pinching the toes, etc., so that the car floor fluctuation is within 75 mm (in 2000, Ministry of Construction Notification No. 1429 “Determining the structure of the elevator controller”) Defined value).

  Here, the process of general high-rise apartments and office buildings: 80m as the standard, and the load fluctuation amount in the cage, the rope safety factor: 12 and the rope safety factor: 10 (safety defined by the Building Standards Act) It is assumed that the allowable rope strain amount is 0.092% when the value is the minimum value. At this time, the allowable strain amount when the safety factor is 10 from the no-load state is 0.55%. Therefore, in order to make the safety factor 10 or more, it is necessary to set the rope strain amount to 0.55% or less.

  FIG. 9 is a graph showing the relationship between the strand pitch multiple and the rope pitch multiple when the rope strain amount is 0.55%. The case where the breaking strength of the material of the steel wire is examined under four conditions of 1770 MPa, 1910 MPa or less, 2300 MPa or less and 3200 MPa is shown. In the graph of FIG. 9, the rope strain amount is less than 0.55% if the region is outside the line (the region where the strand pitch multiple and the rope pitch multiple are large).

  Here, the elevator rope having a breaking strength of 1770 MPa is an elevator rope of “Type B” (JIS G 3525) defined by JIS standard (Japan Industrial Standards), and the elevator rope having a breaking strength of 1910 MPa is defined by “T” It is an elevator rope of “seed” (JIS G 3525). These two elevator ropes are generally widely used. The breaking strengths 2300 MPa and 3200 MPa have higher strength than the above-described commonly used elevator ropes.

As shown in FIG. 9, it can be understood that the strand pitch and the rope pitch need to be increased in order to make the rope strain amount: 0.55% or less as the breaking strength of the elevator rope increases. In the present invention, in a high-strength elevator rope having a breaking strength of 3200 MPa, it can be seen that if P ₂ = 2.5 and P ₁ = 17.2, the rope strain can be 0.55% or less. In other words, even if the number of elevator ropes is increased (breaking strength 3200 MPa) and the number is reduced, the rope strain will be 0.55% or less if P ₂ = 2.5 and P ₁ = 17.2 are satisfied. The amount of change in rope elongation that occurs when the rope tension fluctuates can be sufficiently reduced.

Even when strands and steel wires having break strengths other than the above are used, by substituting a value of 1/10 of the rope break strength (safety factor: 10) into equation (32), the amount of rope strain: 0.55 It is possible to calculate the rope pitch P ₁ and the strand pitch P ₂ that are necessary to make the percentage or less.

Next, a test was conducted to confirm the validity of the calculation based on the above guidelines. FIG. 10 is a side view schematically showing a rope produced for the test. The test elevator rope 101 has the diameter d ₀ of the elevator rope 1: 8.0 (mm), the number N _{1 of} strands 102: 4 (lines), and the number of outermost steel wires 103 of the strands 102: 7 (lines) ), The number of strands 103a of the outermost layer of the steel wire 103: 7 (pieces), rope base length (length in the central axis direction of strand twist) L ₁ : 21000 (mm), additional load (tension T ₀ ) 6000 (N), steel wire longitudinal elastic modulus E: 205000 MPa, steel wire transverse elastic modulus G: 170800 MPa, and the surface is covered with resin 104 so that the rope does not lose its shape.

FIG. 11 is a graph showing the relationship between the rope elongation amount δL ₁ , the rope pitch P ₁ and the strand pitch P ₂ . In FIG. 11, the calculated value and the experimental value are compared. In the elevator rope 101 of FIG. 10, the rope pitch: P ₁ (mm), the strand pitch: P ₂ (mm), the steel wire pitch: P ₃ (mm), and experiments and calculations were performed under the following conditions 1 to 3. .

Condition 1: P ₁ = 90 (mm), P ₂ = 16 (mm), P ₃ = 12 (mm)
Condition 2: P ₁ = 180 (mm), P ₂ = 32 (mm), P ₃ = 18 (mm)
Condition 3: P ₁ = 360 (mm), P ₂ = 60 (mm), P ₃ = 24 (mm)
FIG. 11 shows calculated elongation values and experimental values (actual values) of each rope at L ₁ = 21000 (mm) and T ₀ = 6000 (N). The error between the calculated value and the experimental value for all three levels is less than ± 10%, and it can be confirmed that sufficient calculation accuracy is secured.

Thus, the strands pitch P ₂ given rope strain amount required as elevator wire rope (0.55%) is suppressed below the "ratio a rope pitch P ₁ against the rope diameter d" to "rope diameter d It is understood that the ratio “b” may be in a range satisfying the following expression (32).

  When the above equation (32) is arranged with the left side as b, the above equation A is obtained.

  As described above, according to the present invention, even if the rope breaking strength is improved and the number of ropes is reduced, the amount of change in the rope elongation that occurs due to fluctuations in the rope tension due to the elevator getting on and off can be reduced. It has been shown that a wire rope can be provided.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  DESCRIPTION OF SYMBOLS 1,101 ... Elevator rope, 2,102 ... Strand, 3,103 ... Steel wire, 3a, 103a ... Elementary wire, 104 ... Resin, 30 ... Twist central axis, 31 ... Axis perpendicular to strand cross section.

Claims (12)

In an elevator rope formed by twisting a plurality of strands formed by twisting a plurality of steel wires,
When the diameter of the elevator rope is d (mm), the winding interval of the strand is the rope pitch P ₁ , and the winding interval of the steel wire is the strand pitch P ₂ , the ratio a of the P _{1 to} the d, and the d Elevator rope, wherein the P ₂ ratio b and breaking strength of the elevator rope T (N) satisfies the equation a below.

However, in the above formula A, E: longitudinal elastic modulus (MPa) of the material used for the elevator rope, G: transverse elastic modulus (MPa) of the material used for the elevator rope, N: of the strand The number. The elevator rope according to claim 1, wherein the P ₁ is 17.2 and the P ₂ is 2.5.   The elevator rope according to claim 1 or 2, wherein the breaking strength of the steel wire is 3200 MPa.   The elevator rope according to claim 1, wherein the breaking strength of the steel wire is 2300 MPa.   The elevator rope according to claim 1, wherein the breaking strength of the steel wire is 1910 MPa.   The elevator rope according to claim 1, wherein the breaking strength of the steel wire is 1770 MPa. In an elevator rope formed by twisting a plurality of strands formed by twisting a plurality of steel wires,
The steel wire is formed by twisting a plurality of strands,
When the diameter of the elevator rope is d (mm), the winding interval of the strand is the rope pitch P ₁ , and the winding interval of the steel wire is the strand pitch P ₂ , the ratio a of the P _{1 to} the d, and the d the elevator ropes, characterized in that P ₂ ratio b and breaking strength of the elevator rope T (N) satisfies the following equation.

However, in the above formula A, E: longitudinal elastic modulus (MPa) of the material used for the elevator rope, G: transverse elastic modulus (MPa) of the material used for the elevator rope, N: of the strand The number. The elevator rope according to claim 7, wherein the P ₁ is 17.2 and the P ₂ is 2.5.   The elevator rope according to claim 7 or 8, wherein the breaking strength of the steel wire is 3200 MPa.   The elevator rope according to claim 7, wherein the breaking strength of the steel wire is 2300 MPa.   The elevator rope according to claim 7, wherein the breaking strength of the steel wire is 1910 MPa.   The elevator rope according to claim 7, wherein the breaking strength of the steel wire is 1770 MPa.

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