JP2022138922A - Pulley and elevator - Google Patents

Abstract

To provide a pulley that can be reduced in weight and cost while maintaining reliability.SOLUTION: A resin pulley 5A is formed while containing a resin and includes a body part 7, an inner peripheral part 9 provided on an inner peripheral side of the body part 7 and an outer peripheral part 8 provided on an outer peripheral side of the body part 7. The resin pulley 5A further includes an expansion suppression part 10 of which expansion coefficient at the time of absorption of water is smaller than the body part 7.SELECTED DRAWING: Figure 2

Description

The present invention relates to pulleys and elevators.

An elevator generally has a structure in which a vertically movable car and a counterweight are connected by an elevator rope.

FIG. 1 is a diagram showing an example of the configuration of an elevator 100. As shown in FIG. In the elevator 100, as shown in FIG. 1, a car 1 that can move vertically (in the direction of the double arrow in the figure) in the hoistway 6 and a counterweight 2 are connected to a main rope (elevator rope ) 4. The main rope 4 is driven by a hoist (not shown) attached to the sheave 3, one end is fixed to the top of the car 1 through a pulley 5 fixed to the top, and the other end is a counterweight 2. affixed to the top of the

Here, from the viewpoint of reducing the burden on workers, it is desired to improve the portability and installation workability of elevator parts. Resin parts have a specific gravity about 1/7 that of metal parts, and are very lightweight, so they are often used as materials for elevator parts. When a resin part is used as a strength part such as a pulley, for example, it is required to have high mechanical properties such as tensile strength and creep property, as well as properties with little dimensional change due to water absorption.

Considering such characteristics, conventionally, reinforced nylon (polyamide) containing a predetermined amount of reinforcing fiber such as glass fiber, such as PA6, PA66, polyamide 610 (PA610), polyamide 612 ( PA612), polyamide 11 (PA11), polyamide 12 (PA12), and other glass fiber reinforcing materials are known to be used (see Patent Document 1).

JP 2020-56419 A

However, when the resin pulley described in Patent Literature 1 is applied to an elevator, the pulley becomes large and bulky. Since reinforcing fibers such as glass fibers are expensive, when the resin pulley described in Patent Document 1 is applied to an elevator, the entire part contains reinforcing fibers, so the cost increases according to the amount of reinforcing fibers. There is a problem of becoming

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pulley capable of achieving weight reduction and cost reduction while maintaining reliability.

In order to solve the above-described problems, in one aspect of the present invention, there is provided a main body portion formed containing a resin, an inner peripheral portion provided on the inner peripheral side of the main body portion, and a main body portion provided on the outer peripheral side of the main body portion. and an outer peripheral portion having an outer circumference, the pulley comprising an expansion suppressing portion having an expansion coefficient smaller than that of the main body portion when water is absorbed.

ADVANTAGE OF THE INVENTION According to this invention, the pulley which can achieve weight reduction and cost reduction while maintaining reliability can be provided.

It is a figure which shows an example of a structure of an elevator. 4 is a diagram showing the configuration of the resin pulley of Embodiment 1. FIG. FIG. 10 is a diagram showing the configuration of a resin pulley according to Embodiment 2;

Hereinafter, embodiments and examples according to the present invention will be described with reference to sentences or drawings. However, the structure, materials, and other specific numerical values shown in the present invention are not limited to the embodiments taken up here, and can be appropriately combined and improved without changing the gist of the invention. Elements that are not directly related to the present invention are omitted from the drawing.

In the following description, the same or similar components are distinguished by the reference numerals with subscripts, and the same or similar components are generically referred to by the main body of the code without the subscripts.

First, an embodiment of the present invention will be described. The resin pulley 5A for an elevator of the present embodiment includes a body portion 7, an outer peripheral portion 8 provided on the outer peripheral side of the main body portion 7, an inner peripheral portion 9 provided on the inner peripheral side of the main body portion 7, and a resin An expansion suppressing portion 10 provided concentrically with the circumference of the pulley 5A (or main body portion 7) is included. The body portion 7, the outer peripheral portion 8, and the inner peripheral portion 9 are all arranged concentrically at the center of the boss hole.

The elevator 100 of this embodiment includes a main rope 4, a hoist (not shown) that drives the main rope 4, a resin pulley 5A fixed to the top, and a counterweight 2 connected to one end of the main rope 4. and a car 1 that is connected to the other end of a main rope 4 and moves up and down in a hoistway 6 by driving the main rope 4 .

Here, embodiments showing various shapes of the resin pulley 5A of the present embodiment are shown in schematic diagrams of FIGS. 2 and 3, respectively.

FIG. 2 is a diagram showing the configuration of the resin pulley 5A of the first embodiment. FIG. 2 is a plan view of the flat resin pulley 5A. The resin pulley 5</b>A has an expansion suppressing portion 10 on the inner peripheral portion 9 of the body portion 7 . In this case, the outer peripheral portion 8 is made of the same material as the main body portion 7 .

FIG. 3 is a diagram showing the configuration of the resin pulley 5A of the second embodiment. FIG. 3 is a plan view of the flat resin pulley 5A. The resin pulley 5</b>A has an expansion suppressing portion 10 on the outer peripheral portion 8 of the body portion 7 . In this case, the inner peripheral portion 9 is made of the same material as the body portion 7 .

In addition, it is not limited to the case where the outer peripheral portion 8 or the inner peripheral portion 9 is used as the expansion suppressing portion 10 , and the main body portion 7 may be configured to be the expansion suppressing portion 10 . In this case, the outer peripheral portion 8 and the inner peripheral portion 9 are made of the same material.

Hereinafter, the configuration of each part of the resin pulley 5A of this embodiment will be described in detail.

(Body portion 7 of resin pulley 5A)
The body portion 7 of the resin pulley 5A of the present embodiment is made of a polyamide resin containing a caprolactam unit as a structural unit. Polyamide resins contain aliphatic polyamide monomer units as structural units. Monomer units of aliphatic polyamides are, for example, caproamide units, octanamide units, decanamide units, undecaneamide units, dodecaneamide units, tetramethylene adipamide units, tetramethylenesuberamide units, tetramethylene sebacamide units, tetramethylene Dodecamide units, hexamethylene adipamide units, hexamethylene sebacamide units, hexamethylene dodecamide units, decamethylene sebacamide units, and the like.

Further, the polyamide resin may contain aromatic polyamide monomer units as structural units, and the aromatic polyamide monomer units are, for example, tetramethylene isophthalamide units, hexamethylene isophthalamide units, octamethylene terephthalamide units, units, nonamethylene terephthalamide units, decamethylene terephthalamide units, undecamethylene terephthalamide units, dodecamethylene terephthalamide units, metaxylylene adipamide units, or metaxylylene sebacamide units.

The material of the body portion 7 is not particularly limited as long as the strength and reliability required for the resin pulley 5A are ensured. For example, resin materials containing at least one of polyimide, polyacetal copolymer, modified polyphenylene ether, polyphenylene sulfide, polyetherimide, polyethersulfone, polyamideimide, polyetheretherketone, phenolic resin, epoxy resin, and unsaturated polyester. and may be a combination of single or multiple resin materials.

(Expansion suppressing portion 10 of resin pulley 5A)
The expansion suppressing portion 10 of the resin pulley 5A of the present embodiment is mainly made of polyamide resin, and may contain a fibrous reinforcing material such as glass fiber or carbon fiber.

As the material of the fibrous reinforcing material contained in the expansion suppressing portion 10, any material can be used without any particular limitation as long as the performance of the expansion suppressing portion 10 is satisfied. Examples of specific materials include high-strength fibers such as glass fibers, carbon fibers, para-aramid fibers, ultra-high molecular weight polyethylene fibers, polyarylate fibers, and polybenzoxazole fibers. The expansion suppressing portion 10 is made of a material containing at least one of these materials.

In the present embodiment, the fibrous reinforcing material contained in the expansion suppressing portion 10 preferably accounts for 10 to 50% by volume of the resin pulley 5A as a whole. More preferably, it is 20 to 40%. If the volume ratio of the fibrous reinforcing material is less than 10%, the effect of suppressing expansion cannot be sufficiently obtained. If the volume ratio of the fibrous reinforcing material is more than 50%, the cost increases and the fatigue strength decreases due to the increase in material interfaces.

The expansion suppressing portion 10 has a water absorption rate of 3.0% or less, preferably 2.5% or less. Here, the water absorption rate refers to the water absorption rate when immersed in pure water for 24 hours under constant temperature and constant humidity of 23° C. and relative humidity of 50%. Water absorption is measured according to ISO62. As described above, since the resin composition has low water absorption, it is possible to suppress dimensional changes and deterioration of physical properties due to swelling and expansion due to water absorption and moisture absorption. The resin pulley 5A of the present embodiment is excellent in dimensional stability and can be provided at a low cost as a pulley for applications requiring precision.

(Modification 1 of the expansion suppressing portion 10)
The expansion suppressing portion 10 can be formed not only by changing the material as described above, but also by changing the shape. For example, the radial length d of the inner peripheral portion 9 can be set at a certain ratio or more with respect to the pulley diameter c (FIG. 2). In order to have sufficient expansion suppressing performance, it is desirable that the ratio of the radial length d of the inner peripheral portion 9 to the pulley diameter c (=d/c) is 6.5% or more. More preferably, it is 6.9 to 10%. Greater than 10% increases weight and cost.

(Modified Example 2 of Expansion Suppression Part 10)
The expansion suppressing portion 10 may be formed so as to cover the outermost layer of at least one of the main body portion 7, the outer peripheral portion 8, and the inner peripheral portion 9 of the resin pulley 5A. In this case, a moisture-proof material can be used as the material of the expansion suppressing portion 10 . In this case, the body portion 7, the outer peripheral portion 8 and the inner peripheral portion 9 are made of the same material.

Moisture-proof materials are based on, for example, polyethylene terephthalate (PET), linear low-density polyethylene (LLDPE), polypropylene (PP), polyethylene (PE), polyamide (PA), amorphous polyolefin (APO), etc. The moisture-impermeable layer is formed by coating a non-conductive, non-halogen, moisture-proof material such as alumina, silica, zinc oxide (ZnO), or titanium oxide (TiO2).

Note that the moisture-proof material may be a multi-coated layer obtained by coating two or more kinds of materials in multiple layers. Methods such as vapor deposition by PVD or CVD, sputtering, and ion plating can be used for coating these substances. It is desirable that the moisture-proof material has a thickness of 1 to 500 μm. More preferably, it is 1 to 250 μm. If the moisture-proof material is thinner than 1 μm, it is difficult to secure the moisture-proof property. Also, if the moisture-proof material is thicker than 500 μm, the cost increases.

A more specific configuration example of the expansion suppressing portion 10 will be described in detail with reference to an example of the resin pulley 5A, which will be described later.

(Effective thickness of resin pulley 5A)
The concept of effective thickness is used to define the shape of the resin pulley 5A. The thinner the effective thickness (2×V/A) derived from the relationship between the pulley volume V and the surface area A, the lighter the weight but the lower the strength. Material costs are lower for smaller effective thicknesses. Therefore, when the pulley diameter is 380 mm or less, the effective thickness is preferably 12 mm or less from the balance between strength and material cost. However, the reduction in effective thickness increases the problem of deformation due to water absorption. If the effective thickness is 12 mm or more, each portion (for example, the inner peripheral portion 9) has a sufficient thickness, so deformation due to water absorption is limited even if the expansion suppressing portion 10 is not particularly provided.

(Elevator 100 using resin pulley 5A)
The resin pulley 5A including the main body portion 7, the outer peripheral portion 8, the inner peripheral portion 9, and the expansion suppressing portion 10 described above can be applied to an elevator 100, an example of which is shown in FIG.

At this time, the resin pulley 5A needs to have a structure that supports the tension between the car 1 and the counterweight 2, and it is desirable that the modulus of longitudinal elasticity of the resin pulley 5A is at least 2 GPa or more. More preferably, the modulus of longitudinal elasticity of the resin pulley 5A is within the range of 2.5 to 5 GPa. Conditions for forming the resin pulley 5A that satisfies this modulus of longitudinal elasticity include, for example, a cylinder temperature of 240 to 280.degree. C. and a mold temperature of 40 to 120.degree. The polyamide must have a molecular weight of at least 100,000.

Since the resin pulley 5A has a sufficient modulus of longitudinal elasticity in this manner, the resin pulley has long-term reliability.

Next, as an example of the present invention, a more specific example of the resin pulley 5A for an elevator of the present invention will be shown.

(Evaluation of deformation due to water absorption)
In order to evaluate the deformation of the resin pulley 5A due to water absorption, analysis was performed using the finite element method (FEM). A pulley FEM model composed of a finite number of elements divided by element division corresponding to the finite element method is produced from the shape data of the resin pulley 5A. In the pulley FEM model, material information for each member is assigned to each member and nodes are defined at the boundaries of the elements. Deformation analysis is performed by calculating an equation of motion for each node based on the material information.

From the relationship between the water absorption rate and the longitudinal elastic modulus of the resin pulley 5A, the longitudinal elastic modulus corresponding to the water absorption rate in each example was calculated, applied to the pulley FEM model, and used for the FEM analysis. Poisson's ratio was set to 0.4. Also, the amount of dimensional change due to water absorption was simulated by applying a thermal load of 1K.

The water absorption rate refers to the water absorption rate when immersed in pure water for 24 hours under constant temperature and constant humidity of 23° C. and relative humidity of 50%. Water absorption is measured according to ISO62.

(Example 1)
In Example 1, a resin pulley 5A having a main body portion 7 mainly composed of polyamide and an expansion suppressing portion 10 arranged on the inner peripheral side (inner peripheral portion 9) of the main body portion 7 is assumed, and an FEM model is produced. did. The outer peripheral portion 8 is made of the same material as the main body portion 7 .

(Example 2)
In the second embodiment, the resin pulley 5A is assumed to have a body portion 7 mainly composed of polyamide and an expansion suppressing portion 10 formed by coating the outermost layer of the inner peripheral portion 9 with a moisture-proof material. Then, an FEM model was created. The outer peripheral portion 8 and the inner peripheral portion 9 are made of the same material as the main body portion 7 .

(Example 3)
In Example 3, a resin pulley having a body portion 7 mainly composed of polyamide and an expansion suppressing portion 10 formed by setting the radial length d of the inner peripheral portion 9 to 7% of the pulley diameter. Assuming 5A, an FEM model was created. The outer peripheral portion 8 and the inner peripheral portion 9 (expansion suppressing portion 10 ) are made of the same material as the main body portion 7 .

(Example 4)
In Example 4, a resin pulley having a body portion 7 whose main component is polyamide and an expansion suppressing portion 10 formed by setting the radial length d of the inner peripheral portion 9 to 10% of the pulley diameter. Assuming 5A, an FEM model was created. The outer peripheral portion 8 and the inner peripheral portion 9 (expansion suppressing portion 10 ) are made of the same material as the main body portion 7 .

(Comparative example)
In the comparative example, an FEM model was produced assuming a resin pulley having a main body portion 7 mainly composed of polyamide, an outer peripheral portion 8 and an inner peripheral portion 9 . In this comparative example, the resin pulley does not have the expansion suppressing portion 10 .

Table 1 shows the analysis results of each example and comparative example.

In Example 1, the inner peripheral portion 9 contains glass fiber as the expansion suppressing portion 10, and the change rate of the inner diameter with respect to water absorption was as low as 0.03%. Since Examples 2 to 4 also had the expansion suppressing portion 10, the inner diameter change rate due to water absorption was low.

On the other hand, in the comparative example without the expansion suppressing portion 10, the change rate of the inner diameter due to water absorption was 0.1%, which was about three times as large as that in the other examples. If the inner diameter changes by about 0.1%, a gap is created between the resin pulley and the bearing, which may cause slippage, abnormal wear, dropout, and the like. From the above, the effectiveness of the expansion suppressing portion 10 for suppressing deformation due to water absorption was analytically shown.

(Preparation and evaluation of resin pulley 5A)
The resin pulley 5A can be produced by injection molding or cast polymerization of raw materials such as caprolactam. At this time, the resin pulley for an elevator shown in FIG. 2 can be produced by using a raw material mixed with a fibrous reinforcing material for the portion of the expansion suppressing portion 10 .

Based on Example 3, a resin pulley 5A was produced by cast polymerization. The effective thickness was 12 mm, and the inner peripheral length was 7% of the diameter. Also, based on the comparative example, a resin pulley was produced in the same manner. The effective thickness was 12 mm. A water supply test was performed on these two pulleys.

As a result of measuring the dimensions of each pulley after the water absorption test, the inner diameter change rates were 0.03% and 0.1%, respectively. From this result, the effectiveness of the expansion suppressing portion 10 for suppressing deformation due to water absorption was experimentally demonstrated.

Since the resin pulley 5A according to the present embodiment is a lightweight and high-strength resin pulley, it is excellent in portability. Moreover, since the expansion suppressing portion 10 is provided, it is possible to suppress dimensional change due to water absorption, which is effective in extending the life of the resin pulley 5A. Therefore, it is possible to reduce maintenance frequency and maintenance work processes, and extend the service life of elevators.

It should be noted that the above-described embodiments and examples are specifically described to aid understanding of the present invention, and the present invention is not limited to having all the described configurations. For example, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to delete, replace with another configuration, or add another configuration for a part of the configuration of each embodiment.

1: car, 2: counterweight, 3: sheave, 4: main rope, 5A: resin pulley, 6: hoistway, 7: main body, 8: outer periphery, 9: inner periphery, 10 : expansion suppressing part, 100: elevator

Claims (7)

A pulley formed containing resin and having a body portion, an inner peripheral portion provided on the inner peripheral side of the main body portion, and an outer peripheral portion provided on the outer peripheral side of the main body portion,
A pulley comprising an expansion suppressing portion having an expansion coefficient smaller than that of the main body portion when water is absorbed. A pulley according to claim 1,
The pulley, wherein the resin is a polyamide resin containing a caprolactam unit as a structural unit. A pulley according to claim 1,
The pulley, wherein the expansion suppressing portion is the inner peripheral portion or the outer peripheral portion and contains a fibrous reinforcing material of 10 to 50% by volume. A pulley according to claim 1,
The pulley, wherein the expansion suppressing portion is the inner peripheral portion, and the ratio of the radial length of the inner peripheral portion to the diameter of the pulley is 6.5 to 10%. A pulley according to claim 1,
The pulley, wherein the expansion suppressing portion is formed of a moisture-proof material covering an outermost layer of at least one of the main body portion, the inner peripheral portion, and the outer peripheral portion with a thickness of 1 to 500 μm. The pulley according to any one of claims 1 to 5,
A pulley having a diameter of 380 mm or less, and an effective thickness (2×V/A) derived from a relationship between a volume V and a surface area A of the pulley of 12 mm or less. A pulley according to claim 1;
car and
a counterweight and
a main rope connecting the car and the counterweight via the pulley;
and a hoist for moving the car up and down in a hoistway by driving the main rope.

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