JPH05118386A - Toothed belt - Google Patents

Abstract

PURPOSE:To improve molding stability so as to eliminate an improper out-tooth while improving both performances of durability and noiseproof by improving a structure of threads extended in the lengthwise direction of a fabric belt. CONSTITUTION:A fabric of coating a tooth part formed in a belt main unit is woven by a thread 6 extended in a belt lengthwise direction consisting of a covering thread with a synthetic fiber crimped thread 9 wound on a core thread 8 consisting of elastic thread and a thread extended in a belt width direction consisting of a synthetic fiber spun yarn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothed belt in which tooth portions formed on a belt body are covered with a woven cloth, and more particularly to improvement of the woven cloth.

[0002]

2. Description of the Related Art In recent years, toothed belts having tooth portions formed on a belt main body covered with a woven cloth have come to be used in various fields, such as high-speed rotation, high load and high temperature. It is also increasingly used under severe conditions. Therefore, when used under such harsh conditions, deterioration of the material constituting the belt is apt to progress, and the belt life often shortens due to early scattering of teeth and cutting of the core. There is a strong demand for improved durability.

Further, as automobiles and household machines have become more sophisticated in recent years, low noise is strongly required, and reduction of noise during belt driving has become a serious problem.

Therefore, in order to improve the durability of the toothed belt, for example, as disclosed in Japanese Patent Application Laid-Open No. 60-81536, a woven fabric having wooly textured yarn of high viscosity polyamide fiber is used. As disclosed in JP-A-55-40319 and a toothed belt, one of the weft threads and the warp threads of the woven cloth has a strength residual ratio of 90 after 400 hours in an atmosphere at a temperature of 120 ° C. % Heat-resistant synthetic fiber, while the other thread is made of 6-nylon, 6,
6-nylon, which is a synthetic fiber, and one of the yarns is exposed on the surface of the woven fabric more than the other yarn, and the other yarn is more than the one yarn on the back face of the woven fabric. A toothed belt using a woven fabric that is exposed has been proposed.

On the other hand, in order to reduce noise, for example,
As disclosed in Japanese Utility Model Laid-Open No. 62-87238, a toothed belt in which at least one layer of coarse woven fabric is embedded in the belt body and at least one surface woven fabric is attached to the surface of the belt body, Actual exploitation Sho 63-119
As disclosed in Japanese Patent Laid-Open No. 49, a toothed belt has been proposed which uses only a cloth for RFL bonding and uses a canvas which does not rubberize at least the contact surface with the pulley.

However, the above-mentioned toothed belts and and the above-mentioned toothed belts can not ensure low noise, but the toothed belts and and, conversely, can ensure low noise. Although it is possible to do so, the durability cannot be ensured, and it is the current situation that it is not possible to achieve both durability and low noise.

Therefore, the present applicant previously filed Japanese Patent Application No. 3-9.
As described in the specification and drawings of No. 9154,
We applied for a toothed belt in which a woven fabric is composed of a yarn made of elastic yarn which is a crimped yarn of synthetic fiber and extending in the longitudinal direction of the belt, and a yarn made of spun yarn of synthetic fiber and extending in the belt width direction. Further, according to this toothed belt, the spun yarn of synthetic fiber is configured by bundling short fibers unlike the long fiber yarn, and many naps are present on the yarn surface, and when the naps come into contact when the belt is driven. It exerts a cushioning effect that softens the impact received. This cushioning effect not only suppresses the impact fatigue of the woven cloth but also alleviates the shock applied to the core body, so that the service life of the woven cloth and the core body can be significantly increased, and the toothed belt is The effect that the impact sound generated when meshing with the can be reduced and the noise can be reduced is exhibited.

[0008]

However, while the spun yarn exhibits the cushioning effect as described above due to its nap, the frictional resistance between the yarns is great and the stretchability of the crimped yarns is restricted and the spun yarns shrink. It cannot be processed sufficiently and a large elongation cannot be obtained. For this reason, at the time of press-fit molding, elongation at a low load, which is capable of stably forming the shape of the tooth portion, does not appear, and tooth ejection failure occurs.

The present invention has been made in view of the above points, and an object thereof is to improve the structure of the yarns extending in the longitudinal direction of the belt of the woven cloth to improve the durability and noise characteristics as in the prior application. It is intended to improve molding stability and eliminate tooth defects while improving both performances.

[0010]

In order to achieve the above object, the solution means of the present invention according to claim 1 is a toothed belt in which tooth portions formed on a belt main body are covered with a woven cloth, The above-mentioned woven fabric is composed of a core yarn made of an elastic yarn and a covering ring yarn in which a crimped yarn of a synthetic fiber is wound and extending in a belt longitudinal direction, and a yarn made of a spun yarn of a synthetic fiber and extending in a belt width direction. It is a woven thing.

According to a second aspect of the present invention, in the above case, the yarn extending in the belt width direction is composed of spun yarn of meta-aromatic polyamide fiber, and is woven more than the yarn extending in the belt longitudinal direction. This means that the surface of the cloth was exposed a lot.

[0012]

With the above construction, in the present invention according to claim 1, since the spun yarn of synthetic fiber is used as the yarn extending in the belt width direction, many raised fibers on the yarn surface make contact with the belt during driving. The impact received when doing is softened and a cushioning effect is developed. The cushioning effect reduces the impact applied to the core body, extends the life of the woven fabric and the core body, and reduces the impact sound generated when the toothed belt meshes with the pulley, thus reducing noise.

Further, since the yarn extending in the longitudinal direction of the belt is formed by winding the crimped yarn of the synthetic fiber around the core yarn made of the elastic yarn, the yarn (spun yarn) extending in the belt width direction is raised. Even if the elasticity of the crimped yarn is restricted,
The core yarn located inside is prevented from coming into contact with the nap and the elastic function thereof is not restricted, so that the elastic function of the core yarn ensures the elasticity of the yarn and obtains a large elongation. Therefore, sufficient shrinking is possible, a large elongation at low load is exhibited during press-fitting molding, a tooth portion can be stably formed, and tooth ejection failure is significantly reduced.

According to the second aspect of the present invention, the yarn extending in the belt width direction is composed of meta-aromatic polyamide fiber,
In addition, since it is exposed more on the surface of the woven fabric than the yarn extending in the longitudinal direction of the belt, the abrasion resistance is remarkably improved due to the characteristics of the material.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a toothed belt 1 according to an embodiment of the present invention.
Indicates. The toothed belt 1 comprises a belt body 2,
At the pitch line position of the belt body 2, glass fiber,
The core cords 3, 3, ... Which are made of carbon fiber and aromatic polyamide fiber and have low elongation and high strength are embedded in parallel. Further, tooth portions 4, 4, ... Are integrally formed on one surface of the belt body 2, and the tooth portion 4 is covered with a woven cloth 5.

As the rubber constituting the belt main body 2 and the tooth portion 4, NR (natural rubber), SBR (styrene butadiene rubber), CR (chloroprene rubber), NBR.
(Nitrile rubber), CSM (Hypalon rubber) and H
A single or blend of NBR (hydrogenated nitrile rubber) and urethane elastomer (elastic body) are used.

The woven cloth 5 is woven by threads 6 extending in the belt longitudinal direction and threads 7 extending in the belt width direction. As a feature of the present invention, the yarn 6 is a covering yarn in which a crimped yarn 9 of synthetic fiber is wound around a core yarn 8 made of, for example, a polyurethane-based elastic yarn, as shown in detail in FIG. It will be. The yarn 7 is composed of spun yarn of synthetic fiber, and the spun yarn is formed by bundling short fibers, and many naps are present on the yarn surface.

Here, as the synthetic fibers which are the materials of the yarns 6 and 7, nylon fibers, polyester fibers, aromatic polyamide fibers, aromatic polyester fibers and the like are used. Particularly, the yarn 6 extending in the longitudinal direction of the belt is preferably an aliphatic synthetic fiber having a relatively low melting point such as nylon fiber and polyester fiber which can be easily crimped, and the yarn 7 extending in the belt width direction has abrasion resistance and Aromatic synthetic fibers with high heat resistance are desirable. In particular, it is preferable to use a meta-type aromatic synthetic fiber and expose a large amount of this on the surface of the woven fabric 5 because the abrasion resistance can be further improved.

Thus, the reason why the spun yarn of synthetic fiber is used as the yarn 7 extending in the belt width direction is that it provides a cushioning effect to alleviate the impact received when the raised fibers of the spun yarn come into contact when the belt is driven. Thus, both durability and noise performance of the toothed belt 1 can be improved.

Further, the core yarn 8 made of an elastic yarn as the yarn 6 extending in the longitudinal direction of the belt and the crimped yarn 9 of the synthetic fiber wound around the yarn extends in the belt width direction (spun yarn).
This is because even if the stretchability of the crimped yarn 9 is restricted by the raised hair 7, the contact of the core yarn 8 located inside with the raised hair is avoided and the elastic function thereof is not restricted. And this heart thread 8
By the elastic function of, the elasticity of the yarn 6 can be secured and a large elongation can be obtained, which enables sufficient shrinkage processing, and during press-fitting, a large elongation at low load can be expressed and stable. As a result, the tooth shape can be formed, and the tooth ejection failure can be significantly reduced.

When the woven cloth 5 as described above is used, an adhesive containing a large amount of rubber paste or rubber component (for example, RFL)
By impregnating the inside of the woven cloth 5, the spun yarn 9 is appropriately bundled without reducing the cushioning effect,
Wear defects can be improved. However, even if this adhesive treatment is not performed, the above properties are not lost as long as spun yarn is used.

Next, the toothed belts according to Examples I to III of the present invention were manufactured, and the performance test was conducted together with the toothed belts according to the comparative example and the conventional example.

First, woven fabrics used in Examples I to III of the present invention, comparative examples and conventional examples are prepared. The structure is shown in Table 1.
Table 2 shows the physical property measurement results. Further, FIG. 3 shows the relationship between the strength in the stretchable direction of the woven cloth and the elongation (SS). In each example, the warp yarn shown in Table 1 was used as the yarn extending in the belt width direction, and the weft yarn was used as the yarn extending in the belt longitudinal direction.

[0025]

[Table 1]

[0026]

[Table 2]

Then, after the well-known rubber gluing treatment was applied to the woven fabric having the structure shown in Table 1, the tooth portion of the belt body having the structure shown in FIG. 1 was covered with this woven fabric to obtain a toothed belt. .. That is, a woven cloth that has been treated with rubber paste is wrapped around a toothed cylindrical mold, a core cord is spun on it, and an unvulcanized rubber sheet of a certain thickness is wrapped around it. Then, by a well-known press-fitting molding method in which rubber is press-fitted into the tooth groove of the drum, PLD = 0.686 mm, belt width =
A toothed belt having 19 mm and the number of belt teeth = 125 T was obtained.

Thereafter, this toothed belt was wound around a drive and driven pulley of 18T (18 teeth), a tension of 20 kg was applied, and the belt was run under the conditions of a load of 4 ps, a rotation speed of 1000 rpm, and an ambient temperature of 100 ° C. Then, Table 3 shows the running time at the time when the teeth are scattered.

[0029]

[Table 3]

From the data in Table 3, the invention examples I to III were obtained.
Then, it can be seen that the running time corresponding to the belt life is greatly extended compared to the comparative example and the conventional example. In particular, the elongation of Example III of the present invention is outstanding.

In the same running test, the belt residual strength after running for 100 hours was measured, and the results shown in Table 4 were obtained.

[0032]

[Table 4]

As a result, Examples I to III of the present invention were much more excellent in belt residual strength than the conventional examples, and Examples I to III of the present invention were more excellent in belt residual strength than the Comparative Examples.

Further, the noise level generated during running was measured in the same running test, and the results shown in Table 5 were obtained.
In the noise measurement test, the ambient temperature was set to room temperature, the measured value was fixed at 1000 rpm, and the noise amount at 300 Hz (primary meshing frequency) and 600 Hz (secondary meshing frequency) was measured.

[0035]

[Table 5]

From the data in Table 5, the invention examples I to III were obtained.
In both cases, there is no great difference from the comparative example, but it can be seen that the noise level is greatly reduced compared to the conventional example.

In addition, Table 6 shows how many toothed belts were manufactured, and how many of them failed in tooth extraction.

[0038]

[Table 6]

From the data in Table 6, the invention examples I to III were obtained.
It can be seen that the number of defective teeth is much smaller than that of the comparative example.

[0040]

As described above, according to the present invention as set forth in claim 1, since the spun yarn of synthetic fiber is used as the yarn extending in the belt width direction, the belt is driven by many naps existing on the yarn surface. Occasionally, the cushioning effect can be exerted by softening the impact when contacted, and both the durability and noise performance of the toothed belt can be improved.
Further, since the yarn extending in the belt longitudinal direction is formed by winding the synthetic yarn crimped yarn around the core yarn made of the elastic yarn, it is possible to avoid the contact of the internally disposed core yarn with the nap and to improve the elasticity of the yarn. As a result, a sufficient shrinkage process can be performed, and during press-fitting, a large elongation at a low load can be expressed, and tooth defects can be significantly reduced.

According to the second aspect of the present invention, the yarn extending in the belt width direction is composed of the meta-aromatic polyamide fiber, and is more exposed on the woven fabric surface than the yarn extending in the belt longitudinal direction. Therefore, the wear resistance can be significantly improved depending on the characteristics of the material.

[Brief description of drawings]

FIG. 1 is a configuration diagram of threads extending in a belt longitudinal direction of a woven fabric.

FIG. 2 is a perspective view of a toothed belt.

FIG. 3 is a data diagram showing the relationship between strength and elongation in the stretchable direction of a woven fabric.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Toothed belt 2 ... Belt main body 4 ... Tooth portion 5 ... Woven fabric 6 ... Thread extending in belt longitudinal direction 7 ... Thread extending in belt width direction 8 ... Core thread 9 ... Crimping thread

Claims (2)

[Claims] 1. A toothed belt formed by covering a tooth portion formed on a belt main body with a woven fabric, wherein the woven fabric comprises a core yarn made of an elastic yarn and a crimped yarn of synthetic fiber wound around the core yarn. A toothed belt comprising a yarn made of a covering yarn and extending in the longitudinal direction of the belt, and a yarn made of spun yarn of synthetic fibers and extending in the belt width direction. 2. The yarn extending in the belt width direction is made of spun yarn of meta-aromatic polyamide fiber, and is more exposed on the woven fabric surface than the yarn extending in the belt longitudinal direction. 1. The toothed belt according to 1.