JPH102379A - Toothed belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To express high strength and high modulus of elasticity by forming a back rubber part and a toothed rubber part by a carbon fiber where a thermoplastic elastomer and a core cord are single twisted, and conducting adhesion processing with the same thermoplastic elastomer as those of the back rubber part and the toothed rubber part before single twisting is conducted. SOLUTION: A toothed rubber part 2 is integraly formed by a desigated pitch on one side of a back rubber part 1 of a toothed belt A, and a core cord 3 as a tenslle body is buried by a designated pitch in the cross direction of the belt between both parts. The back rubber part 1 and the toothed rubber part 2 are formed by polyamide-base or polyurethane-base thermoplastic elastomer, the core cord 3 is formed by single twisting yarn of polyacrylonitrile-base, pitch-base carbon fiber, and the collected and paralleled yarns are soaked in a solution of the same themaoplastic elastomer as those of the back rubber part 1 and the toothed rubber part 2, to be made adhere, which are single twisted. Thus, thermoplastic elastomer can be penetrated into every nook and corner between the fibers so as to sufficiently express high strength, high modulus of elasticity and water resisting property of the carbon fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothed belt and, more particularly, to a measure for bonding to a rubber layer when carbon fiber is used as a core cord.

[0002]

2. Description of the Related Art Conventionally, rubber belts and cast urethane belts are well known as toothed belts used for precision transmission in OA equipment and the like. Each of these belts has a back rubber portion, a large number of tooth rubber portions provided integrally with the back rubber portion at a predetermined pitch in the belt longitudinal direction, and a belt between the back rubber portion and the tooth rubber portion. It has a core cord buried at a predetermined pitch in the belt width direction so as to extend in the longitudinal direction, and only the back rubber part and the tooth rubber part are molded with rubber or molded with cast urethane. The only difference is that.

However, any of the above belts has the following disadvantages. That is, in the case of a rubber belt,
During the meshing transmission with the pulley, the tooth rubber portion is scraped off by friction with the pulley, and the scraped-off rubber powder (rubber used for the belt is generally black) is used to surround the belt of the device. Is undesirably aesthetically pleasing. In addition, due to the physical properties of the rubber, not only the recycling design cannot be performed, but also post-processing such as shaping after forming the belt cannot be performed.

In the case of cast urethane belts, after-curing is required in the manufacturing process, and there is a problem that productivity is reduced. In addition, similarly to the above-described rubber belt, there is a problem that it is not possible to carry out a recycling design or to give a shape after forming the belt.

[0005] On the other hand, a toothed belt in which the back rubber portion and the tooth rubber portion are formed of a thermoplastic elastomer has been proposed to solve such a problem (see Japanese Patent Application Laid-Open No. 7-27178).

[0006]

However, in the toothed belt of the above-mentioned proposed example, since the glass cord or the aramid fiber is used as the core cord, the core cord is sized due to the hygroscopicity caused by the material. And the performance of the toothed belt is deteriorated.

In view of this, it is conceivable to employ a carbon fiber having no dimensional change due to hygroscopicity and having high strength and a high elastic modulus as the core body cord. However, since the carbon fiber has poor adhesiveness to the thermoplastic elastomer, By twisting this and embedding it between the back rubber part made of thermoplastic elastomer and the tooth rubber part as the core cord, the thermoplastic elastomer does not sufficiently penetrate inside the core cord, and the thermoplastic elastomer There is a problem that the core cord peels off at the interface with the thermoplastic elastomer, and the carbon fiber cannot exhibit the functions of high strength and high elastic modulus as described above.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and it is an object of the present invention to provide a core cord which is firmly adhered to a thermoplastic elastomer so that the carbon fibers constituting the core cord have high strength and high strength. An object of the present invention is to provide a sufficient elastic modulus and to prevent a reduction in belt performance due to a dimensional change due to moisture absorption.

[0009]

In order to achieve the above-mentioned object, the present invention is characterized in that the core body cord is subjected to an adhesive treatment before a twisted cord is formed.

Specifically, the present invention provides a back rubber portion, a plurality of tooth rubber portions provided integrally with the back rubber portion at a predetermined pitch in the longitudinal direction of the belt, the back rubber portion and the tooth rubber portion. And a core cord embedded at a predetermined pitch in the belt width direction so as to extend in the belt longitudinal direction between the belt and the belt.

That is, according to a first solution of the present invention, both the back rubber portion and the tooth rubber portion are made of a thermoplastic elastomer. Further, the core cord is made of carbon fiber subjected to single twist, and is subjected to an adhesive treatment with the same thermoplastic elastomer as the back rubber portion and the tooth rubber portion before the single twist is applied. .

According to a second aspect of the present invention, in the first aspect, a polyamide-based or polyurethane-based thermoplastic elastomer is used as the thermoplastic elastomer.

According to a third aspect of the present invention, in the first aspect, a polyacrylonitrile-based, pitch-based or viscose-based carbon fiber is used as the carbon fiber constituting the cord. I do.

With the above arrangement, according to the first to third solutions of the present invention, at the time of the bonding treatment, the carbon fibers are not in the form of a core cord (single twist cord) but are in a aligned state, and the adhesive is The thermoplastic elastomer permeates into every corner between the fibers.

Accordingly, the thermoplastic elastomer is sufficiently penetrated inside the core cord formed by twisting the bundle of carbon fibers into which the thermoplastic elastomer is sufficiently penetrated. When this core body cord is embedded between the back rubber portion and the tooth rubber portion, the cord is continuously integrated with the thermoplastic elastomer forming the back rubber portion and the tooth rubber portion, as if it were a back rubber portion and a tooth rubber portion. It is as if the thermoplastic elastomer of the part had penetrated into the core cord.

[0016] As a result, the bonding area between the back rubber portion and the tooth rubber portion and the core body cord is increased, and the two are firmly adhered to each other and the separation at the interface is eliminated, so that the carbon fiber constituting the core body cord has high strength, A high elastic modulus and water resistance are sufficiently exhibited, and there is no dimensional change due to moisture absorption, and there is no reduction in belt performance due to the change.

[0017]

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

FIG. 1 shows a toothed belt A according to an embodiment of the present invention. The toothed belt A is provided with a back rubber portion 1, and on one surface of the back rubber portion 1, a large number of tooth rubber portions 2 meshing with the tooth portions of the pulley during meshing transmission are integrated at a predetermined pitch in the belt longitudinal direction. It is molded into. A core cord 3 as a tensile member is buried between the back rubber portion 1 and the tooth rubber portion 2 so as to extend in the longitudinal direction of the belt and at a predetermined pitch in the belt width direction. Such an arrangement of the core body cords 3 is made by spirally winding one core body cord 3 around a forming drum at the time of molding.
A tooth cloth (reinforced canvas) 4 is integrally attached to the tooth rubber portion 2.

Both the back rubber portion 1 and the tooth rubber portion 2 are made of a polyamide-based or polyurethane-based thermoplastic elastomer.

As a feature of the present invention, the above-mentioned cord 3
Is made of a single twisted yarn obtained by twisting a polyacrylonitrile (PAN) -based, pitch-based or viscose-based carbon fiber, and can exhibit functions of high strength and high elastic modulus. What is particularly important is that the core cord 3 is bonded with the same thermoplastic elastomer as the back rubber portion 1 and the tooth rubber portion 2 before the single twist is applied. That is, the back rubber part 1
The bundled yarn which is in the aligned state before the single-twisted yarn is immersed in a solution in which the same thermoplastic elastomer as the tooth rubber portion 2 is dissolved in a solvent, and is subjected to an adhesive treatment. The core body cord 3 is obtained by single twisting.

By bonding the bundled carbon fiber yarn, that is, the untwisted and aligned yarn, the thermoplastic elastomer can penetrate into every corner between the carbon fibers. By twisting the treated bundled yarn, the core cord 3 having the thermoplastic elastomer sufficiently permeated therein can be obtained.

In the toothed belt A employing the core cord 3 as a tensile member, the thermoplastic elastomer of the back rubber portion 1 and the tooth rubber portion 2 and the thermoplastic elastomer permeated into the core cord 3 are integrated. The contact area between the back rubber part 1 and the tooth rubber part 2 and the core body cord 3 is increased, so that both can be firmly adhered to each other and separation at the interface can be prevented. In addition, the carbon fiber constituting the core body cord 3 can sufficiently exhibit high strength, high elastic modulus, and water resistance, and there is no dimensional change due to hygroscopicity, thereby preventing a decrease in belt performance due to the dimensional change. .

Next, examples of the present invention will be specifically described together with comparative examples.

The configurations of the toothed belts of the present invention and the comparative example are as follows.

<Core cord> A twisted yarn having the structure shown in Table 1 was used.

[0026]

[Table 1]

<Back rubber part and tooth rubber part> Polyamide-based thermoplastic elastomer <Shape of toothed belt> Tooth pitch: 2 mm Number of teeth: 110 Belt width: 6 mm The toothed belts of the present invention and comparative examples were used. Table 2 shows the data of the strong residual rate after running for 24 hours.

[0028]

[Table 2]

As is clear from the data, the present invention and comparative examples 1 and 2 using carbon fiber as the cord were used.
2 is Kevlar fiber (aramid fiber) as a core code
The strength retention ratio was higher than Comparative Example 3 using the glass fiber or Comparative Example 4 using the glass fiber.

Table 3 shows the data of the adhesion test.

[0031]

[Table 3]

As is evident from the data, Comparative Example 2 after the twisting was applied by the bonding treatment had a very low value as compared with the other examples.

Table 4 shows data on the belt elongation and the residual strength of the belt after running the toothed belt for 1000 hours.

[0034]

[Table 4]

As is clear from this data, in Comparative Example 1 in which the cord was twisted, the fiber was broken by bending at the pulley, and thus the belt elongation was larger than those of the other examples, and the belt elongation was large. The residual strength ratio was low.

[0036]

As described above, according to the present invention,
Both the back rubber portion and the tooth rubber portion are made of a thermoplastic elastomer, and the same thermoplastic elastomer as the back rubber portion and the tooth rubber portion is used before twisting the carbon fiber, which is a single-stranded cord of carbon fiber, to the carbon fiber. Since the bonding process
By the sufficient penetration of the thermoplastic elastomer into the core cord, the adhesive strength between the back rubber portion and the tooth rubber portion can be improved. High elastic modulus and water resistance can be exhibited without regret, and a toothed belt with good performance can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a toothed belt according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 back rubber part 2 tooth rubber part 3 core cord A toothed belt

Claims (3)

[Claims] A back rubber portion; a plurality of tooth rubber portions provided integrally with the back rubber portion at a predetermined pitch in the belt longitudinal direction; and a belt longitudinal direction between the back rubber portion and the tooth rubber portion. And a core cord buried at a predetermined pitch in the belt width direction so as to extend in the belt direction, wherein the back rubber portion and the tooth rubber portion are both made of a thermoplastic elastomer, The toothed belt, wherein the cord is made of a carbon fiber subjected to single twist, and is subjected to an adhesive treatment with the same thermoplastic elastomer as the back rubber portion and the tooth rubber portion before the single twist is applied. . 2. The toothed belt according to claim 1, wherein the thermoplastic elastomer is a polyamide-based or polyurethane-based thermoplastic elastomer. 3. The carbon fiber constituting the core cord,
The toothed belt according to claim 1, wherein the belt is a polyacrylonitrile-based, pitch-based, or viscose-based carbon fiber.