JP2002039275A - Toothed belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a scouring process of canvass for a tooth cloth of a toothed belt and to improve belt length accuracy by uniforming a canvass thickness. SOLUTION: The tooth cloth 5 of the toothed belt 1 comprises the canvass woven from bimetallic strip type conjugated fiber used as a weft 6 arranged in the belt longitudinal direction. By using the bimetallic strip type conjugated fiber as the weft 6, the scouring process becomes unnecessary and ductility of the canvass necessary for belt manufacture can be provided by contracting the canvass just by an RFL liquid and/or heating during rubber cement treatment. The belt length accuracy can be improved by uniforming the canvass thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a toothed belt,
The present invention relates to a toothed belt using a bimetal conjugate fiber in which two types of polymers having different heat shrinkage ratios are combined in parallel in a filament single yarn and woven using a weft arranged in a belt longitudinal direction.

[0002]

2. Description of the Related Art A conventional toothed belt is composed of a rubber compound using chloroprene as a raw material rubber on teeth and a back, and an RFL using SBR vinylpyridine latex as a latex component.
(Resorcinol-formalin-latex) Consists of a tooth cloth used in the longitudinal direction of the belt using glass fiber cord or aramid fiber cord bonded with a liquid as the core wire and crimped nylon as the weft. It is used as a belt for industrial synchronous transmission and OHC driving (overhead cam driving) for automobiles.

The OHC driving toothed belt has a high environmental temperature due to the compact engine room and the FF, and the conventional toothed belt using chloroprene as a raw material rubber has cracks at the back and the root of the tooth. The belt was easily cut due to a phenomenon leading to tooth chipping or deterioration of the glass core wire due to bending under high temperature. Therefore, in recent years, in particular, in response to the demand for extending the life of toothed belts for automobiles, hydrogenated nitrile rubber (H-NBR) obtained by hydrogenating chlorosulfonated polyethylene (CSM) or acrylonitrile-butadiene copolymer has been developed. It has been used as a raw rubber for rubber compounds.

On the other hand, not only the raw rubber in the rubber compound but also the core wire and the tooth cloth have been improved. Among them, in the case of a tooth cloth, since the teeth of the toothed belt are formed by a press-fitting method, a high elongation is required for the weft of the tooth cloth, and after weaving to increase the elongation, the canvas is subjected to a scouring process. Through the process of hot water washing, the fabric is shrunk in the weft direction. Then, R
It is treated with FL liquid and / or rubber glue to form a toothed belt cloth. Generally, a wooly yarn or a urethane elastic yarn and a covering yarn of a synthetic fiber are used as the weft of a canvas in order to obtain elongation. Both required a scouring step.

[0005]

However, in the conventional tooth cloth, it is difficult to control the processing temperature of the wooly yarn, the uniform false twist cannot be performed, the yarn has a random thickness, and the fiber itself has high rigidity. As a result, it did not have a smooth canvas due to an uneven surface like a towel. Such toothed belts using canvas vary in PLD value (the distance between the pitch line, which is the center line of the core wire, and the bottom surface of the belt tooth), and the length of the belt molded with the same mold becomes non-uniform. A problem has occurred.

Further, wooly yarns or urethane elastic yarns and covering yarns of synthetic fibers are generally used as the weft of canvas for elongation. After weaving both, the canvas is washed with hot water. And a scouring step of shrinking the canvas in the weft direction was required. When the canvas passes through this scouring step, the thickness of the canvas becomes non-uniform, which is one of the causes of a decrease in belt length accuracy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and eliminates the need for a scouring step of a cloth for a toothed belt and further improves the belt length accuracy by making the thickness of the cloth uniform. Aim.

[0008]

That is, according to the first aspect of the present invention, there is provided the above-mentioned tooth portion which has teeth arranged at predetermined intervals along the length direction and a back portion in which the cord is embedded. In a toothed belt having a surface covered with a tooth cloth, the tooth cloth is a toothed belt which is a canvas woven using a bimetal conjugate fiber for a weft arranged in a belt longitudinal direction,
By using a bimetallic conjugate fiber for the weft, the scouring process is not required, and the canvas shrinks only by heating at the time of RFL liquid and / or rubber glue treatment, and the elongation of the canvas required for belt production can be obtained. In addition, by making the canvas thickness uniform, the belt length accuracy can be improved.

In the invention according to claim 2 of the present application, there is provided a toothed belt in which the bimetallic conjugate fiber is at least one selected from polyamide fiber, polyester fiber, and acrylic fiber.

In the invention according to claim 3 of the present application, the fineness of a single yarn of the bimetallic conjugate fiber is 2 to 10 dt.
ex is in the toothed belt.

[0011]

FIG. 1 is a sectional perspective view of a toothed belt according to the present invention. A toothed belt 1 has a plurality of teeth 2 along a belt longitudinal direction (arrows in the figure) and a glass fiber cord. Alternatively, it is composed of a back part 4 in which a core wire 3 made of aramid fiber cord is embedded, and a tooth cloth 5 is adhered to the surface of the tooth part 2.

The raw rubber used for the tooth portion 2 and the back portion 4 is heat-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 tooth cloth 5 uses a bimetal conjugate fiber for the weft 6 arranged in the longitudinal direction of the belt, and a filament yarn of aramid fiber composed of para-aramid fiber and meta-aramid fiber for the warp yarn 7, nylon 6, nylon 6 Plain and twill fabrics made of filament yarns such as polyamides such as .6 nylon and 12 nylon, vinylon and polyester;
Such as satin fabric.

As shown in FIGS. 2 and 3, the bimetallic conjugate fiber 8 is a composite of different polymers 8a and 8b having different heat shrinkage, molecular weight, crystallinity and the like in parallel within a filament single yarn. And a composite fiber comprising a core and a sheath. Materials to be used are polyamide fiber, polyester fiber and acrylic fiber, and the same material is used. The bimetal-type conjugate fiber 8 is a synthetic fiber spun by eccentrically adhering two kinds of polymers to a fiber axis, and when heat-treated, crimps are generated due to a difference in shrinkage, and the stretchability is excellent.

The bimetal-type conjugate fiber 8
The fineness of the single yarn is 2 to 10 dtex, and 2 dtex
If less than 10 dtex, the abrasion resistance of the canvas lowers and 10 dtex
If it exceeds, the rigidity of the canvas becomes high, and it becomes difficult to obtain a canvas having a smooth surface.

The tooth cloth 5 is treated with an RFL solution, an isocyanate solution, or an epoxy solution. RFL
The liquid was prepared by mixing an initial condensate of resorcinol and formalin in a latex, and the latex used here was styrene. butadiene. It is selected from vinylpyridine terpolymer, hydrogenated nitrile rubber, chlorosulfonated polyethylene, epichlorohydrin and the like.

The RFL-treated tooth cloth is a canvas with rubber which is impregnated and adhered with a rubber composition using a base rubber of the same kind as the rubber used for the tooth portion and vulcanized. Specifically, for example, hydrogenated nitrile rubber, which is the same kind of rubber as the rubber used for the tooth portion, is provided with a reinforcing agent such as carbon black and silica, a vulcanizing agent selected from sulfur or an organic peroxide, and a vulcanization accelerator. After preparing a rubber paste obtained by dissolving the compounded rubber composition with a solvent, the rubber paste is impregnated and adhered, dried, and then vulcanized to obtain a canvas with rubber.

[0018]

The present invention will be described below in detail with reference to examples. Examples 1 to 3 and Comparative Examples 1 and 2 Untreated canvases shown in Table 1 were prepared. The canvas A was immersed in the RFL solution shown in Table 2 and then heat-treated at 200 ° C. for 2 minutes. After immersion in the same RFL solution once more,
Heat treatment was performed at 0 ° C. for 2 minutes. After the scouring treatment shown in Table 3 (washing in hot water at 70 ° C. for 100 minutes), the canvas B was immersed in the RFL solution shown in Table 2 and heat-treated at 200 ° C. for 2 minutes. After being immersed in the same RFL solution once more, heat treatment was performed at 200 ° C. for 2 minutes. Table 3 also shows the results obtained by measuring the strength and elongation in the weft direction of the obtained treated canvases A and B in accordance with JIS L1096 and the results of measuring the density of the canvases. Similarly, Table 3 shows the results of measuring the thickness of the canvas 300 times in accordance with JIS L1096 and calculating the standard deviation.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

An unvulcanized sheet prepared by rolling the RFL-treated canvas and the kneaded rubber shown in Table 4 to a predetermined thickness is prepared, and further, is melt spun as a core wire, and has a wire diameter of about 9 μm which is surface-treated with a silane coupling agent. Approximately 200 glass fiber filaments are bundled into strands, and the three strands are aligned, immersed in each RFL solution in Table 2, dried at 130 ° C. for 2 minutes, baked at 250 to 300 ° C. for 2 minutes, and A lower twisted yarn twisted in the S direction at about 12 times / 10 cm and an ECG-150-3 / 0 glass cord twisted in the Z direction the same number of times were used.

In the preparation of the toothed belt, the above-mentioned tooth cloth was wound around a mold, the glass fiber cord was spun thereon, and then a rubber sheet made of the CR rubber compound shown in Table 4 was further wound. Subsequently, this was vulcanized, and the obtained vulcanized sleeve was cut into a predetermined width to obtain individual belts. The size of the belt is 40S2M710 and the width is 4.0m
m, belt length 710 mm, and tooth shape S2M.

[0024]

[Table 4]

The forming condition of the tooth portion of the obtained toothed belt was visually determined. In addition, the belt axis separation was such that the belt was hung on a toothed pulley having two teeth of 30 and the belt was rotated while applying tension to the belt at an initial load of 16N, and the center distance between the pulleys was measured. Table 3 shows the results obtained by measuring the axial separation of 100 belts and determining the standard deviation. From this result, it can be seen that in this example, the canvas thickness was made uniform and the belt length accuracy was improved.

[0026]

As described above, in the invention described in the present application, the tooth cloth is a toothed belt which is a canvas woven using bimetal conjugate fibers for the weft arranged in the longitudinal direction of the belt. The use of bimetallic conjugate fibers eliminates the need for a scouring step and reduces R
The canvas shrinks only by heating at the time of FL liquid and / or rubber glue treatment, and the elongation of the canvas required for belt production can be obtained, and the uniformity of the canvas thickness improves belt length accuracy. be able to.

[Brief description of the drawings]

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

FIG. 2 shows a cross-sectional view of a bimetallic conjugate fiber used in the present invention.

FIG. 3 shows a cross-sectional view of another bimetallic conjugate fiber used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Toothed belt 2 Tooth part 3 Core wire 4 Back part 5 Tooth cloth 6 Weft 7 Warp 8 Bimetal type conjugate fiber

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4L048 AA16 AA20 AA24 AA30 AA34 AA50 BA01 BA02 CA01 CA02 DA38

Claims (3)

[Claims] 1. A toothed belt having tooth portions arranged at predetermined intervals along a length direction and a back portion in which a cord is buried, wherein a surface of the tooth portion is covered with a tooth cloth. Is a canvas woven using bimetal conjugate fibers for the wefts arranged in the longitudinal direction of the belt. 2. The toothed belt according to claim 1, wherein the bimetallic conjugate fiber is at least one selected from a polyamide fiber, a polyester fiber, and an acrylic fiber. 3. The toothed belt according to claim 1, wherein the fineness of the single yarn of the bimetallic conjugate fiber is 2 to 10 dtex.