JPH09177897A - Tensile substance for belt and transmission belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent bending fatigue resistance without damaging adhesion between a cord braid and a belt body. SOLUTION: A cord braid 11 wherein four or more filament yarns 12 are braided in a cylindrical shape is employed as a tensile substance for a belt embedded in a belt body in such a manner to stretch in the longitudinal direction of the belt. In this case, the cord braid 11 or the filament yarn 12 of which the cord braid consists is immersed in polyethylene emulsion for treatment. This constitution suppresses the occurrence of wear between the filament yarns 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt tension member and a transmission belt embedded in the belt main body of various transmission belts, and more particularly to measures for improving the bending fatigue resistance of the transmission belt.

[0002]

2. Description of the Related Art Conventionally, transmission belts such as toothed belts, V-belts, flat belts and ribbed belts are required to have characteristics such as high strength, high elastic modulus and high dimensional stability. In order to satisfy the above requirement, a reinforcing body such as a reinforcing cord made of fibers or a cloth-like material is embedded as a tensile body in the belt body.

As the tensile body, a twisted yarn formed by twisting a plurality of filament yarns is generally used.
The types thereof can be classified into ply-twisted yarns, single-twisted yarns, rung-twisted yarns and the like depending on the twisting method.

However, in recent years, the demands on the market such as durability and dimensional stability are becoming more and more severe, and it is becoming difficult for the above-mentioned transmission belt using the twisted yarn as a tensile body to meet the above demands. For this reason, the applicant of the present application has previously applied for a tensile body that employs a round braided cord having excellent physical properties instead of the twisted yarn (Japanese Patent Laid-Open Nos. 3-24643 and 3-211041). JP-A-3-21
3747, JP-A-3-2444848, JP-A-3-2444849, JP-A-3-244850, and JP-A-3-244851).

[0005]

By the way, as a result of studying the fatigue mechanism of the round braid when the above-mentioned round braid is used for the tension member of the transmission belt, the filament yarns are It turned out to rub and wear against each other. Therefore, it is desirable to reduce this wear in order to improve the bending fatigue resistance of the round braid. This is a problem that must be solved by all means in consideration of use under various severe conditions such as high load and high temperature required in the market.

As a method of alleviating the wear phenomenon of the tensile body as described above, for example, when the tensile body is a steel wire cord, a hemp thread impregnated with oil is arranged at the center of the steel wire cord as a core yarn. It is known that the above oil causes the oil to seep out to the surface of the cord. It is also possible to apply a silicone treating agent to the surface of the filament yarns to reduce the friction between the filament yarns due to the lubricating properties of silicone.

However, in the tensile body subjected to the above-mentioned method, since the surface of the tensile body, that is, the entire portion of the filament yarn exposed on the outside is covered with oil or silicone, the belt main body is The adhesiveness with the constituent rubber may be impaired, and the performance of the transmission belt may deteriorate.

The present invention has been made in view of the above points, and an object thereof is to obtain excellent bending fatigue resistance without impairing the adhesiveness with the rubber constituting the belt body. Is.

[0009]

To achieve the above object, the present invention is directed to a belt tension member and a transmission belt which are embedded in a belt main body so as to extend in the belt longitudinal direction. A solution was taken.

That is, the first to third solving means of the present invention relate to a belt tensile member, and the first solving means is to form the belt tensile member into a cylindrical shape with four or more filament yarns. It is composed of braided braids. At this time, the round braid is dipped in a polyethylene emulsion at the filament yarn stage before braiding or at the braiding stage after braiding.

A second solution is characterized in that, in the first solution, an aramid fiber is adopted as the filament yarn.

A third solution is that in the first solution, the solid content concentration of the polyethylene emulsion is 1.5 to.
It is characterized by being set to 4.0 wt%.

A fourth solving means relates to a power transmission belt, and the belt tension member according to any one of the first to third solving means is extended in the belt main body in the belt longitudinal direction. It is characterized by being buried.

With the above construction, in the first to fourth solutions, the colloidal particles of polyethylene are not scattered over the surface of the tensile body, that is, the portion appearing on the outside of the filament yarn, and do not cover the entire surface of the filament yarn. Is moderately exposed, whereby the filament yarns forming the round striking braid are prevented from being worn out, and the adhesiveness with the rubber forming the belt body is secured to obtain excellent bending fatigue resistance.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a round braided cord 11 as a belt tension member. This braided braid 11 is obtained by assembling four or more filament yarns 12 by a braiding machine into a cylindrical shape. This round braided cord 11 has the property of being particularly excellent in bending fatigue resistance due to its structural characteristics,
In addition, since it is better in terms of dimensional stability than twisted yarn, if it is used as a tensile member of a transmission belt, both physical properties such as bending fatigue resistance and dimensional stability can be modified. The number of filament yarns 12 constituting the round braid 11 is 4
The number of the braids is equal to or more than that in order to make the braid into a cylindrical shape, and the number of the braids is not particularly limited as long as it is 4 or more.

As the filament yarn 12 constituting the round braided cord 11, aramid fiber, polyester fiber, glass fiber, whisker fiber, metal fiber, etc. may be selected and used according to the purpose, but high strength and high elastic modulus. In order to obtain high dimensional stability and the like, it is preferable to use aramid fiber.

A feature of the present invention is that the round braided cord 11 is used.
Is dipped in a polyethylene emulsion at the filament yarn stage before braiding or at the braiding stage after braiding. This polyethylene emulsion has polyethylene colloid particles as a dispersoid and is dispersed in water as a dispersion medium. A round braid 11 is braided with the filament yarn 12 soaked with this polyethylene emulsion, or a round braid 11 after braiding
When polyethylene is dipped in polyethylene emulsion, the colloidal particles of polyethylene are present in a scattered form on the surface of the round braided cord 11, that is, on the portion of the filament yarn 12 appearing outside, and the filament yarn is not coated on the entire surface of the filament yarn 12. Since the ground surface of 12 is partially exposed, wear of the filament yarns 12 forming the round braided cords 11 can be suppressed by using this as a tensile member of the transmission belt, and adhesion to the rubber forming the belt body can be suppressed. It is possible to secure the property and obtain excellent bending fatigue resistance. In addition, when the round braided cord 11 after the braiding is dipped in a polyethylene emulsion, it is desirable that the impregnation property is smoothly performed by applying ultrasonic waves to the treatment liquid.

The solid content concentration of the polyethylene emulsion is not particularly limited, but the preferred range is from 1.5 to
It is 4.0 wt%. Solid content concentration of 1.5-4.0 wt
It is preferable that the solid concentration is 1.
If it is less than 5 wt%, the amount of polyethylene colloidal particles present on the surface of the round braided cord 11 will be small, and the effect of suppressing the abrasion of the fibers will be reduced, while if the solid content concentration exceeds 4.0 wt%, On the contrary, this is because the amount of the colloidal particles of polyethylene present on the surface of the round braided cord 11 increases and the adhesiveness with the rubber forming the belt body tends to decrease, resulting in abrasion of the fiber and adhesiveness with the rubber. It is preferable to set the solid content concentration within the above range in consideration of the balance.

FIG. 2 shows a toothed belt 21 as a transmission belt.
However, the present invention is not limited to this, and may be a V belt, a flat belt, a ribbed belt, or the like. This toothed belt 21 is
Belt body 24 including back rubber portion 22 and tooth rubber portion 23
The tooth rubber portion 23 is integrally formed on one surface of the back rubber portion 22 with a predetermined pitch interval in the belt longitudinal direction. A cover canvas 25 is attached to the surface of the tooth rubber portion 23. Then, between the belt body 24, that is, the back rubber portion 22 and the tooth rubber portion 23, the circular striking braid 11 is spirally arranged so as to extend in the belt longitudinal direction and to be arranged at a predetermined pitch interval in the belt width direction. Embedded in the toothed belt 21. In addition, the interval between the round braided cord 11 and the cover canvas 25 between the adjacent tooth rubber portions 23 is equal to that of the round braided cord 1.
Considering the adhesiveness of 1 and the belt strength, it is preferable to set it to 0.25 mm.

The rubber constituting the belt main body 24 is not particularly limited, but may be any rubber used for a general transmission belt, for example, natural rubber (NR),
Styrene butadiene rubber (SBR), nitrile rubber (N
BR), hydrogenated nitrile rubber (H-NBR), chloroprene rubber (CR), chlorosulphonated polyethylene rubber (CSM), ethylene propylene rubber (EPDM, E
PM), butadiene rubber (BR), fluororubber (FP
Single or blends such as M).

The cover canvas 25 is made of 6 nylon fiber,
It is made of 6,6 nylon fiber, polyamide fiber, polyester fiber, aramid fiber, etc., and the weaving shape is selected according to the purpose.

Next, a specific example of the present invention will be described.

(Example 1) As the filament yarn 12 made of aramid fiber, 1000 de Technora (trade name, manufactured by Teijin Ltd.) was used, which was used as a polyethylene emulsion, Maycatex HP-50 (trade name, solid content concentration 2.0 wt%). After being dipped in Meisei Kagaku Kogyo Co., Ltd., it is heated and dried in an oven at 100 ° C. for 2 minutes.
The four filament yarns 12 thus treated are applied to a braiding machine and braided at a number of braids of 27 times / 10 cm to obtain a round braided cord 11.

Further, the round braided cord 11 is dipped in an isocyanate compound adhesive to form a subcoat layer,
Then, this is resorcin / formalin latex (R
To form a second coat layer by immersing it in an adhesive (FL)
Then, this is immersed in a glue rubber made of chloroprene rubber to form a top coat layer.

On the other hand, as the rubber constituting the belt main body 24 of the toothed belt 21, a rubber composition containing chloroprene rubber as a main raw material is used. As the cover canvas 25, 6,6 nylon yarn is used as a yarn arranged to extend in the belt width direction, and 6,6 nylon woolly processed yarn is used as a yarn arranged to extend in the belt longitudinal direction. Is.

Then, the toothed belt 21 is formed by a general press-fitting method. With this general press-fitting method, a cover canvas coated with adhesive rubber and dried is wound around a mold having a tooth groove shape of a power transmission belt, and a tensile body and an unvulcanized rubber sheet are sequentially wound onto the mold. A toothed belt is obtained by pressure-molding in a pressure cooker and vulcanization, and then ring-cutting into a predetermined width. In the example 1, the toothed belt 21 obtained has 113 teeth and a pitch of the tooth rubber portion 23 is 8 m.
m, belt width 19 mm.

Example 2 The same as Example 1 except that the polyethylene emulsion has a solid content concentration of 5.0 wt%.

Example 3 The same as Example 1 except that the polyethylene emulsion has a solid content concentration of 4.0 wt%.

Example 4 The same as Example 1 except that the polyethylene emulsion has a solid content of 3.0 wt%.

Example 5 The same as Example 1 except that the solid content concentration of the polyethylene emulsion is 1.5 wt%.

Example 6 The same as Example 1 except that the solid content concentration of the polyethylene emulsion is 0.5 wt%.

(Comparative Example 1) The same as Example 1 except that the dipping treatment with a polyethylene emulsion was not carried out.

(Comparative Example 2) Instead of dipping treatment with a polyethylene emulsion, a silicone treatment agent Pol was used.
Example 1 is the same as Example 1 except that the round braid was dipped in onMF-55 (trade name, solid content concentration 0.5 wt%, manufactured by Shin-Etsu Chemical Co., Ltd.) and dried by heating at 100 ° C.

Table 1 shows the constructions of the round braids used in Examples 1 to 6 and Comparative Examples 1 and 2.

[0036]

[Table 1]

Further, the above Examples 1 to 6 and Comparative Examples 1 and 2
Adhesive strength to the rubber of the round braided in and the running test for evaluating the bending fatigue resistance of the toothed belt obtained in each Example and Comparative Example, in the following manner,
Table 2 shows the results.

(Procedure of Adhesive Strength Test) The adhesive strength was measured by a generally called T test (based on JIS L 1017). In other words, the round braided cord 11 that is bonded to a predetermined mold
And a rubber composition constituting the belt body 24 of the toothed belt 21 are set, and a heat history of 35 minutes at 148 ° C. is added,
As shown in FIG. 3, a sample in which one end of the round braided cord 11 was embedded in a 1 cm square dice-shaped rubber block 24 ′ was prepared, and the pulling force of the round punched braid 11 from the rubber block 24 ′ was measured.

(Procedure of Bending Fatigue Test) As shown in FIG. 4, four large pulleys (diameter 60 mm) 31 constituting a belt bending tester and four small pulleys arranged between the adjacent large pulleys 31 are shown. The toothed belt 21 is wound around the (diameter 30 mm) 32 and the weight 33 is applied to the toothed belt 21 with a load of 80 kgf at 5500 rpm.
I made it run. Then, after 1 × 10 ⁸ times of bending and 5
The belt residual strength ratio after × 10 ⁸ times was calculated, and the fatigue property was evaluated.

[0040]

[Table 2]

As is clear from the data in Table 2, in Examples 1 to 6, the filament yarn 12 of the round braided cord 11 was used.
It can be seen that the bending fatigue resistance of the toothed belt 21 is improved without impairing the adhesive force by the immersion treatment with polyethylene emulsion. Particularly, in Examples 1 and 3 to 5 in which the solid content concentration of the polyethylene emulsion was 1.5 to 4.0 wt%, good results were obtained in all evaluation items.

In Example 2, in which the solid content concentration of the polyethylene emulsion was 5.0 wt%, the adhesive force was lower than in Comparative Example 1 because the colloidal particles of polyethylene occupied on the surface of the filament yarn 12 were relatively large. However, the residual strength ratio (residual strength) was comparable to the other examples,
Moreover, it is better than Comparative Example 1, and in the overall evaluation in consideration of both of these evaluations, there is no problem in using the round braided cord 11 of Example 2 as the belt tension member.

Further, in Example 6 in which the solid content concentration of the polyethylene emulsion is 0.5 wt%, since the colloidal particles of polyethylene occupying the surface of the filament yarn 12 are relatively small, the remaining strength ratio (residual strength) is different. The value was slightly lower than the example, but higher than Comparative Example 1,
The round braided cord 11 can be used as a belt tension member without any problem.

However, the residual strength ratio (residual strength) in Comparative Example 1 not treated with polyethylene emulsion was lower than that in Example 6, and the residual strength ratio (residual strength) was further increased in Example 2 treated with silicone. It was low and the adhesion was extremely low.

In each of the above embodiments, the round braid 11
However, the polyethylene emulsion treatment was applied to the filament yarn 12 which is a stage before string making,
Even if the round braided cord 11 after the braiding is treated with a polyethylene emulsion, the same effect can be obtained.

[0046]

As described above, according to the present invention,
A round braid or a filament yarn constituting the same is dipped in a polyethylene emulsion and used as a tensile member of a transmission belt.Therefore, due to the scattering of colloidal particles of polyethylene on the filament surface, abrasion between the filament yarns is prevented. In addition to suppressing, the adhesiveness with the rubber forming the belt body can be secured, and excellent bending fatigue resistance can be obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged view of a round braided cord.

FIG. 2 is a cross-sectional view showing the overall configuration of a toothed belt.

FIG. 3 is a perspective view of an adhesion test sample.

FIG. 4 is a schematic configuration diagram of a belt running tester.

[Explanation of symbols]

 11 Round braid (tensile body) 12 Filament yarn 21 Toothed belt (transmission belt) 24 Belt body

Claims (4)

[Claims] 1. A tensile member for a belt, which is embedded in a belt main body so as to extend in the longitudinal direction of the belt, comprising a round braid braided into a cylindrical shape with four or more filament yarns. Is a tension member for a belt, which is dipped in a polyethylene emulsion at the filament yarn stage before braiding or at the braiding stage after braiding. 2. The belt tensile member according to claim 1, wherein the filament yarn is an aramid fiber. 3. The tension member for a belt according to claim 1, wherein the polyethylene emulsion has a solid content concentration of 1.5 to 4.
A tensile member for a belt, which is set to 0 wt%. 4. A transmission belt, wherein the belt tension member according to claim 1 is embedded in a belt body so as to extend in a belt longitudinal direction.