JP2002039274A - Toothed belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toothed belt with superior durability causing no separations between rubber foundation cloths and hardly causing any wear or failures such as shear cracks even when traveling for a long time. SOLUTION: This toothed belt 1 comprises a plurality of tooth parts 4 along a belt longitudinal direction and a back part 2 embedded with cores 3, and a tooth cloth 5 is adhered to surfaces of the tooth parts 4. The tooth cloth 5 is a composite canvass of a foundation cloth 6 and a foundation cloth 7 integrated by an adhesive. The foundation cloth 6 is a woven fabric woven from warps composed of a filament yarn or a spun yarn comprising cotton or nylon and wefts composed of a composite yarn stranded from an urethane elastic yarn and a filament yarn or a spun yarn comprising cotton or nylon. The foundation cloth 7 is a woven fabric woven from warps composed of a monofilament yarn of rigid fiber and wefts composed of a composite yarn stranded from an urethane elastic yarn and a filament yarn or a spun yarn of rigid 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 toothed belt having a tooth portion covered with a base fabric.

[0002]

2. Description of the Related Art Conventionally, in a toothed belt used for power transmission, a tooth portion is covered with a base cloth in order to prevent a mesh portion from being damaged. As the base fabric, a woven fabric composed of flexible fibers typified by nylon fiber is widely used, but the teeth that repeatedly contact the pulley are susceptible to bending fatigue due to long-term use, resulting in wear of the tooth cloth and teeth. And many shear cracks occurred. For the above problems, when designing a belt with emphasis on wear resistance and tooth chipping resistance,
It has been proposed to use a fabric with a low coefficient of surface friction. The coefficient of surface friction is determined by the chemical composition of the fiber, the form of the constituent yarn,
Although it is affected by various factors such as the woven composition, specifically, (1) a woven fabric using a rigid fiber represented by an aramid fiber, (2) a woven fabric using a fiber having a large diameter and a low yarn density,
(3) A woven fabric using a monofilament yarn as a warp or a weft, and a woven fabric obtained by combining the above configurations are known in the world.

[0003]

However, a toothed belt using the above-described woven fabric for a tooth cloth is excellent in abrasion resistance and tooth chipping resistance, but for example, (1) rigid belts represented by aramid fibers. In the case of a woven fabric using conductive fibers, aramid has low reactivity in molecular structure and poor adhesion to rubber, so that the woven fabric may peel off from the rubber when the belt is run.
Also, (2) a woven fabric using a fiber having a low density and a large diameter, or (3)
When a weft or a woven fabric using a monofilament yarn as the weft is used as a tooth cloth, the anchor effect is low due to less irregularities on the fiber surface, and there is also a problem in adhesiveness to rubber.

In view of such a background, Japanese Patent Laid-Open No. 9-1
No. 0879 discloses a toothed belt with canvas using a composite yarn in which aramid fiber yarn is wound around a crimped yarn of synthetic fiber as a core yarn, and a synthetic fiber is further coated around the core yarn. In other words, the crimped yarn as the core yarn has excellent elasticity, the aramid fiber wound on the core yarn bears the strength, and the bulky or crimped yarn of the nylon fiber or polyester fiber used for the covering yarn is It is said that adhesion to rubber is improved. However, what is in substantial contact with the pulley is a bulky or crimped yarn of a flexible fiber such as a nylon fiber or a polyester fiber, which is a covering yarn. From the viewpoint, it is unsatisfactory for the above reasons. In recent years, with the advancement of functions and performance in the field of the automobile industry, power transmission belts are also required to have high added functions. As described above, since the required performance and function differ between the front and back surfaces of the canvas, the canvas having the conventional configuration cannot meet the demand at present.

In view of the above background, the present applicant proposes the present invention. A toothed belt in which teeth are laminated and covered with a tooth cloth has a base cloth having a high adhesive strength with rubber. It has been found that a composite fabric in which a base fabric having a configuration excellent in wear resistance and sound resistance is integrated with an adhesive is used as a tooth cloth.

[0006]

That is, according to the first aspect of the present invention, there are provided a plurality of teeth arranged at predetermined intervals along a length direction, and a back having a core wire embedded therein. In a toothed belt having a surface covered with a tooth cloth, the tooth cloth is (A)
A composite canvas in which a base fabric having at least one configuration of (B) and a base fabric having at least one configuration of (C) and (D) are integrated via an adhesive, (A) The constituent yarn is made of spun yarn. (B) The constituent material is made of cotton fiber or nylon fiber. (C) The warp or weft is made of monofilament yarn. (D) The constituent material of warp and weft. Are made of rigid fibers, and (a) the composite canvas is laminated and coated on the teeth so that the base fabric adheres to the rubber. By using a base cloth having a good adhesion to rubber (A) and (B) as shown in (A) and (B) on the rubber bonding surface of the composite canvas, the rubber and the base cloth do not peel off even when used for a long time. By using a base fabric having a low surface friction coefficient such as (C) and (D) for the pulley contact surface of the composite canvas, a toothed belt excellent in wear resistance and tooth chipping resistance can be provided. .

According to a second aspect of the present invention, in the toothed belt according to the first aspect, the rigid fibers are aramid fibers. By selecting aramid fiber with excellent heat resistance among rigid fiber, retention of physical properties at high temperature,
It is possible to provide a belt having excellent dimensional stability.

According to a third aspect of the present invention, there is provided a tooth having a plurality of teeth arranged at predetermined intervals along the length direction and a back having a core wire embedded therein, the surface of which is covered with a tooth cloth. In the attached belt, the tooth cloth is (C) a composite yarn in which a filament yarn or a spun yarn made of cotton or nylon and a filament yarn or a spun yarn made of cotton or nylon and a urethane-based elastic yarn are twisted. A composite yarn obtained by twisting a woven fabric obtained by weaving the configured weft, a filament yarn or a monofilament yarn of a rigid fiber, and a filament yarn or spun yarn of a rigid fiber and a urethane-based elastic yarn. And a woven fabric formed by weaving warp yarns formed by the method described above, wherein the composite fabric is laminated and coated on the teeth so that the base fabric is bonded to rubber. To do And butterflies. (C) Base cloth (d) Both the base cloth and the base cloth have shrinkage in the weft direction by forming the weft as a composite yarn with a urethane-based elastic yarn, and (c) the base cloth has good adhesion to rubber. By using natural cotton fiber or nylon fiber for warp and weft, there is no separation between the rubber base fabrics even during long running, and (d) the base fabric uses rigid fibers for the warp and weft. It shows excellent wear resistance and tooth chipping resistance, and does not affect the stretchability in the weft direction by using a filament yarn or a monofilament yarn for the warp.

According to a fourth aspect of the present invention, in the toothed belt according to the third aspect, the rigid fibers are aramid fibers. By selecting aramid fiber with excellent heat resistance among rigid fiber, retention of physical properties at high temperature,
It is possible to provide a belt having excellent dimensional stability.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a toothed belt 1 according to the present invention. The toothed belt 1 is composed of a plurality of teeth 4 along the longitudinal direction of the belt and a back 2 in which a cord 3 is embedded.
The tooth cloth 5 is stuck on the surface of the. The tooth cloth 5 has a structure in which a base cloth 6 and a base cloth 7 are laminated and combined. More specifically, the base cloth 6 has one surface adhered to the back portion 2 and the other surface adhered to the base cloth 7, and the base cloth 7 has one surface adhered to the base cloth 6 and the other surface adhered to a pulley (not shown). )).

The base fabric 6 is a base fabric selected from a woven fabric, a knitted fabric, a nonwoven fabric and the like. In addition, it is preferable that the base fabric 7 that comes into contact with the pulley is a high-strength woven fabric. Usually, the combination of the base cloth and the base cloth is performed by various methods such as a heat sealing method, a bonding processing, and a mechanical sewing method such as a needle punch method or a stitch bonding method using a thread. It is preferable that the composite is firmly formed by an interposed bonding process. Specifically, after the resin composition that has been melt-softened is pressure-bonded to one of the base fabrics, once cooled, heated again, and the other base fabric is attached at the time of softening the resin composition, a fusion bonding method, An adhesive method and the like in which an adhesive is applied to the surface to be bonded of the base fabric and adhered thereto are exemplified. The method of applying the adhesive includes a doctor method, a roll method, an inversion method, a spray method, and a powder dispersion method. The adhesive used for the bonding process is not limited, and known and publicly-known ones can be used.For example, an adhesive such as an acrylate ester emulsion, a urethane-based resin, and an ethylene-vinyl acetate copolymer may be used. It is generally used, and among them, urethane-based resin is preferable because of its excellent adhesion.

After the base cloth is bonded as described above, pre-drying is carried out by applying pressure with a constant load. The predrying conditions vary depending on the thickness and type of the base fabric,
It is preferable to carry out at 0 ° C. for about 5 to 10 minutes. After the completion of the preliminary drying, curing is performed. In the case of curing, it is preferable to perform heat treatment while pressing as described above.

As the fiber material constituting the base cloth, known and publicly usable ones can be used. For example, natural fibers such as cotton and hemp, inorganic chemical fibers such as metal fibers and glass fibers, and polyamides, polyesters, polyethylenes and the like can be used. Organic chemical fibers such as polyurethane, polystyrene, polyfluoroethylene, polyacryl, polyvinyl alcohol, wholly aromatic polyester, and wholly aromatic polyamide are exemplified.

However, it is an essential condition that the base cloth 6 on the rubber bonding surface and the base cloth 7 on the pulley contact surface have at least the following conditions. Specifically, the cloth 6 is a base cloth having a specific configuration having good adhesiveness to rubber, and the base cloth 7 comes into contact with a pulley at the time of driving.
It is a base fabric having a specific configuration excellent in tooth chipping resistance.

More specifically, as the base fabric 6 to be bonded to rubber, it is preferable to use a fiber such as cotton or nylon which has high reactivity in molecular structure and has excellent adhesion to rubber. Further, the form of the fiber is desirably a structure having a high anchor effect. For example, a spun yarn is preferably used rather than a filament yarn. Rigid fibers are generally considered to have low adhesion to rubber, but when spun yarn is used, adhesion is good. The type of the base fabric is not limited to a woven fabric, a knitted fabric, a nonwoven fabric, and the like. For example, the use of a nonwoven fabric results in a belt structure having excellent flexibility.

The base cloth 7 which comes into contact with the pulley preferably has a structure having a low surface friction coefficient in order to exhibit good wear resistance and tooth chipping resistance, and is woven in a plain weave, twill weave, satin weave or the like. Preferably, a woven fabric is used. As the material, it is preferable to use rigid fibers, and specific examples include wholly aromatic polyester fibers and heterocyclic rigid polymer fibers such as polyparaphenylenebenzobisoxazole,
In addition, there may be mentioned wholly aromatic polyamide fibers such as meta-aramid and para-aramid. Of these, aramid fibers having excellent heat resistance are preferably used. As the form of the fiber, a filament yarn may be used as a constituent yarn to increase the unevenness due to the intersection of the warp and the weft to reduce the surface friction coefficient. In addition, lowering the weaving density and using fibers having a large diameter are effective means for lowering the surface friction coefficient.

Further, in the molding by the press-fitting method which is used as a known technique, since the shrinkability is required in the weft direction of the canvas, the weft of the base cloth 6 and the base cloth 7 is twisted with the urethane-based elastic yarn. It is preferred to use a combined yarn. When a monofilament yarn is used for the base cloth 7, it is preferable to use it for the warp so as not to affect the shrinkage in the weft direction.

The thus-composited tooth cloth 5
According to a known technique, after dipping in a resorcinol-formalin-latex liquid (RFL liquid), friction is performed by rubbing the unvulcanized rubber into the tooth cloth 5, or in a soaking liquid in which the rubber is dissolved in a solvent after dipping in the RFL liquid. Perform immersion treatment.
The RFL solution is a mixture of an initial condensate of resorcinol and formalin and a rubber latex, and a molar ratio of resorcinol to formalin of 1: 0.5 to 3 is preferable from the viewpoint of increasing the adhesive strength. The initial condensate of resorcinol and formalin is mixed with latex such that the resin content is 10 to 100 parts by weight with respect to 100 parts by weight of the rubber content of the latex, and the total solid content concentration is 5 to 40 parts by weight. %
Adjusted to a concentration. The RFL liquid may be appropriately mixed with a carbon black liquid to blacken the treated material, or a known surfactant may be added in an amount of 0.1 to 5.0% by weight.
Examples of the latex include styrene-butadiene-vinylpyridine terpolymer, chlorosulfonated polyethylene, hydrogenated nitrile rubber, epichlorohydrin, natural rubber, SBR, chloroprene rubber, olefin-vinyl ester copolymer, EPDM and the like. Latex is mentioned.

The raw rubber used for the tooth portion 4 and the back portion 2 includes heat-resistant aging such as hydrogenated nitrile rubber, chlorosulfonated polyethylene (CSM), alkylated chlorosulfonated polyethylene (ACSM), and chloroprene rubber. Rubbers with improved properties are preferred. The hydrogenated nitrile rubber has a hydrogenation rate of 80% or more, and preferably 90% or more in order to exhibit heat resistance and ozone resistance. A hydrogenated nitrile rubber having a hydrogenation rate of less than 80% has extremely low heat resistance and ozone resistance.

The above-mentioned organic peroxide compounded in the polymer component comprising the hydrogenated nitrile rubber and the metal salt of unsaturated carboxylic acid is used as a crosslinking agent, and has a predetermined modulus (tensile modulus) and elongation at break. In order to ensure the degree, it is necessary to blend 0.2 to 10 parts by mass of the organic peroxide with respect to 100 parts by mass of the polymer component as described above to perform crosslinking. The organic peroxide is not particularly restricted but includes, for example, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, di-t
-Butyl peroxide, dibutyl cumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,
5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne, 1,3-bis (t-butylperoxyisopropyl) benzene, t-butyl Peroxyisopropyl carbonate and the like can be used. In addition to such an organic peroxide, an appropriate amount of a sulfur compound, an oxime nitroso compound, or a monomer or polymer generally used as a co-crosslinking agent may be added.

Further, in addition to these, carbon black, a plasticizer, and the like can be appropriately added to the extent that hardness, modulus (tensile elastic modulus) and cutting elongation are secured, and appropriate tear strength is secured. It is preferable that carbon black is blended in an amount of 5 to 50 parts by mass based on 100 parts by mass of the polymer component composed of the hydrogenated nitrile rubber and the unsaturated carboxylic acid metal salt.

The core 3 embedded in the belt body is not limited, and generally, a glass core and an aramid core are used. Further, any of twisted cords composed of polybenzoxazole, polyparaphenylene naphthalate, polyester, acryl, carbon, and steel can be used. The composition of the glass core wire may be either E glass or S glass (high-strength glass), and is not limited by the thickness of the filament, the number of bundled filaments, and the number of strands. Further, a sizing agent used as a bonding material and a protective material for a glass filament during bending, RFL,
It is not limited to an overcoat agent or the like. On the other hand, the aramid core wire is not limited by the difference in the molecular structure of the material, the core wire configuration, the size of the filament, or the adhesive treatment agent. Similarly, there is no particular limitation on the twisted cord of the core wire having another composition.

[0023]

The present invention will be described in more detail with reference to the following examples. Examples 1 to 3 and Comparative Examples 1 and 2 In Examples, a composite canvas obtained by compounding the twill fabric shown in Table 2 with a urethane-based resin by bonding was used as an RFL solution (styrene-butadiene-vinylpyridine terpolymer). 100 parts by weight, resorcinol 14.6 parts by weight, formalin 9.2 parts by weight, caustic soda 1.5 parts by weight, water 262.5
Parts by weight). Next, the above-mentioned tooth cloth is wound around a mold for producing a belt, and a core wire (glass fiber, 1.2 mm diameter).
Was spirally wound at a constant pitch (1.4 mm) at a constant tension, and a 2.5 mm rubber sheet having the composition shown in Table 1 was attached thereon. Furthermore, it is put into a vulcanizing can and formed into a tooth profile by a normal press-fitting method. Then, it is vulcanized under pressure at 160 ° C for 30 minutes, and the back surface of the belt is polished to a certain thickness and cut to a certain width to form teeth Got a belt.

[0024]

[Table 1]

A flat peeling test was carried out in accordance with JIS K6256 to evaluate the adhesion between the rubber and the composite canvas of the toothed belt thus obtained. The sample used for the surface friction coefficient of the belt tooth cloth was obtained by laminating a composite canvas and rubber and vulcanizing them by a flat press. SUS for indenter material
, A constant load of 500 g is applied, and the moving speed is 40 m.
The surface friction coefficient was measured under the condition of m / sec. Table 2 also shows these results.

[0026]

[Table 2]

From the above results, it can be seen that the example is a toothed belt having both the same strong adhesive force as the comparative example 1 and the surface friction coefficient as low as the comparative example 2. Examples 1 and 3 in which nylon fibers were used for the woven fabric on the rubber bonding surface side
Also showed higher adhesive strength than Example 2 using spun yarn of aramid fiber which is a rigid fiber.

[0028]

As described above, according to the invention described in the claims of the present application, a base fabric having a specific configuration having good adhesion to rubber and a specific configuration having excellent wear resistance and chipping resistance are provided. A power transmission belt in which a composite canvas obtained by compounding a base fabric having a specific structure with good adhesion to rubber is laminated and coated on the teeth so that a base fabric having a specific configuration adheres to the rubber. Abrasion, improved durability by contacting the base fabric having a specific configuration excellent in tooth chipping resistance, and by using a base fabric having a good configuration with adhesion to rubber on the other surface, It was possible to provide a belt in which the base fabric and the rubber were not separated from each other even during long running.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Toothed belt 2 Back part 3 Core wire 4 Teeth part 5 Tooth cloth 6 Base cloth 7 Base cloth

Claims (4)

[Claims] 1. A toothed belt having a plurality of teeth arranged at predetermined intervals along a length direction and a back having a core wire buried therein, wherein a surface of the teeth is covered with a tooth cloth. The tooth cloth is a composite canvas in which a base cloth having at least one configuration of (A) and (B) and a base cloth having at least one configuration of (C) and (D) are integrated. (A) constituent yarn is made of spun yarn; (B) constituent material is made of cotton fiber or nylon fiber; (C) warp or weft is made of monofilament yarn; (D) warp and weft; A toothed belt, wherein the constituent material is made of rigid fibers, and (a) the composite canvas is laminated and coated on the teeth so that the base fabric adheres to rubber. 2. The toothed belt according to claim 1, wherein the rigid fibers are aramid fibers. 3. A toothed belt having a plurality of teeth arranged at predetermined intervals along a length direction and a back having a core wire buried therein, wherein a surface of the teeth is covered with a tooth cloth. Tooth cloth is (c) a warp yarn composed of a filament or spun yarn made of cotton or nylon, and a weft composed of a composite yarn formed by twisting a filament yarn or a spun yarn made of cotton or nylon and a urethane elastic yarn. And a weft composed of a composite yarn obtained by twisting a filament yarn or a spun yarn of a rigid fiber and a urethane elastic yarn with a warp yarn composed of a filament yarn or a monofilament yarn of a rigid fiber. And a woven fabric obtained by weaving the composite canvas through an adhesive, characterized in that the composite canvas is laminated and coated on the teeth so that the base fabric adheres to rubber. Toothed belt . 4. The toothed belt according to claim 3, wherein the rigid fibers are aramid fibers.