JPH06323367A - Toothed belt - Google Patents

Abstract

PURPOSE:To provide a toothed belt maintaining wear resistance and tooth chipping resistance even at the time of traveling under an extremely hard condition such as high temperature and high tension, or high temperature and high load so as to have a long traveling service life. CONSTITUTION:This toothed belt has plural tooth parts 2 disposed along the longitudinal direction, a back part 4 with core wire 3 embedded therein, and tooth cloth covering the surface of the tooth part 2. The woof 6 in the belt longitudinal direction of the tooth cloth 5 contains at least Aramid fiber, and the adhesion quantity of the solid part of adhesive stuck to the tooth cloth 5 has the volume part 0. l-0.8 to the volume 1.0 of the tooth cloth 5.

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 improved wear resistance and tooth chipping resistance even when running under high temperature and high tension and under high temperature and high load.

[0002]

2. Description of the Related Art A conventional toothed belt is an RFL containing a rubber compound containing chloroprene as a raw material rubber on its teeth and back and an SBR vinyl pyridine latex as a latex component.
(Resorcin / formalin / latex) Adhesive-treated glass fiber cord or aramid fiber cord is used for the core wire, and crimped nylon is used as a weft thread in the longitudinal direction of the belt. It is used as a belt for OHC drive (overhead cam drive).

This OHC driving toothed belt has a high environmental temperature to be used due to downsizing of the engine room and FF, and in the conventional toothed belt using chloroprene as a raw material rubber, cracks in the back and roots are caused. It was easy to cut the belt due to a phenomenon leading to tooth chipping or deterioration of the glass core wire due to bending at high temperature. Therefore, in recent years, particularly in response to the demand for longer life of toothed belts for automobiles, hydrogenated nitrile rubber (HNBR) obtained by hydrogenating chlorosulphonated polyethylene (CSM) or acrylonitrile-butadiene copolymer is compounded with rubber. It has come to be used as a raw material rubber. This is disclosed in, for example, Japanese Patent Laid-Open No. 62-159827.

On the other hand, not only the improvement of the raw rubber in the rubber compound but also the improvement of the core wire and the tooth cloth have been made. In the case of tooth cloth, for example, one of warp or weft is polyester thread or aramid fiber, and the other thread is 6
JP-A-55-36642 discloses improving heat resistance by using a canvas made of nylon or nylon 6.6. Further, Japanese Utility Model Application Laid-Open No. 62-183147 proposes that at least a wooly textured yarn of aramid fiber and a urethane elastic yarn are used as a weft in a belt longitudinal direction as a tooth cloth.

[0005]

However, a tooth cloth using a woolly textured yarn of a conventional aramid fiber has a random thickness because it is difficult to control the processing temperature of the wooly textured yarn and uniform false twisting is not possible. In addition, since the fiber itself has high rigidity, the surface becomes uneven like a towel, and a smooth canvas cannot be obtained. A toothed belt using such a canvas has a problem that the PLD value (the distance between the pitch line that is the center line of the core wire and the bottom surface of the belt tooth) varies, and the belt length formed by the same mold becomes uneven. There has occurred. Moreover, in conventional tooth cloth, R is used as an adhesive treatment agent.
Although FL liquid and rubber paste were used, when the amount of adhesive treatment adhered decreased, the fabric structure was easily deformed, which resulted in severe abrasion at the intersections of the warp and weft, and The wear resistance was greatly reduced.

The present invention solves such problems, and maintains wear resistance and tooth chipping resistance even during running under extremely harsh conditions such as high temperature and high tension and high temperature and high load, and is long. An object is to provide a toothed belt having a running life.

[0007]

That is, a feature of the present invention is to have a plurality of tooth rubbers arranged along the length direction and a back rubber in which a core wire is embedded, and a tooth cloth on the surface of the tooth rubber. In the toothed belt coated with, at least aramid fiber is used for the weft in the belt longitudinal direction of the tooth cloth, and the solid content of the adhesive treatment agent adhered to the tooth cloth is 1 volume of the tooth cloth. The toothed belt has a volume of 0.1 to 0.8.

FIG. 1 is a sectional perspective view of a toothed belt according to the present invention, and FIG. 2 is a transverse sectional view of the toothed belt shown in FIG. According to this, the toothed belt 1 is composed of a plurality of tooth portions 2 and a back portion 4 in which a core wire 3 made of a glass fiber cord or an aramid fiber cord is embedded along the belt longitudinal direction (arrow in the figure). A tooth cloth 5 is attached to the surface of 2. The raw material rubber used for the tooth portion 2 and the back portion 4 is improved aging resistance to heat such as hydrogenated nitrile rubber, chlorosulfonated polyethylene (CSM), alkylated chlorosulfonated polyethylene (ACSM), and chloroprene rubber. Preferred rubbers are preferred. The hydrogenated nitrile rubber has a hydrogenation rate of 80% or more, 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.

When the toothed belt 1 is used under the condition that the tension and the tension are large together with the load, the tooth cloth of the conventional toothed belt abnormally wears, cracks occur at the root portion relatively quickly, and the life due to tooth loss is eventually caused. Therefore, 100-140 ° C
Under the conditions of high temperature, high load, and high temperature, high tension, it is necessary to reinforce the tooth portion 2.

The canvas used as the tooth cloth 5 is a plain weave,
It is made of a twill fabric, a satin fabric, or the like, and at least the weft yarn 6 in the belt longitudinal direction contains aramid fibers in an amount of 20 to 80% by weight of the total amount of weft yarns in the belt longitudinal direction. That is, the weft yarn 6 is a yarn containing at least aramid fiber, and the specific constitution of the weft yarn is three types of yarns of multi-filament yarn of para-aramid fiber, spun yarn composed of meta-aramid fiber and urethane elastic yarn. Twisted, multifilament yarn of para-aramid fiber, aliphatic fiber yarn (6 nylon,
66 nylon, polyester, polyvinyl alcohol, etc.) and urethane elastic yarn, which are three-ply twisted, or spun yarn made of meta-aramid fiber, and urethane elastic yarn, which are two ply twisted. May be.

The above-mentioned aramid fiber multifilament yarn is a multifilament yarn in which a plurality of filament raw yarns of 0.3 to 1.2 denier are bundled together, or 0.3 to 1.2 denier. It is a multifilament yarn in which a plurality of filament raw yarns are converged, and is made of, for example, para-aramid fibers such as Kevlar, Technora, and Twaron, and meta-aramid fibers such as Nomex and Conex.

When the thickness of the filament raw yarn is less than 0.3 denier, the tensile strength of the tooth cloth in the belt longitudinal direction is lowered and the abrasion resistance due to contact with the pulley is deteriorated. On the other hand, when the thickness of the filament raw yarn exceeds 1.2 denier, the rigidity of the yarn in the direction in which the multifilament yarn of the aramid fiber is driven is excessive during the process of bonding the tooth cloth after weaving. Therefore, the warp and weft as the canvas cannot be balanced, and the wrinkles are generated due to the uneven cloth thickness, which cannot be used for a toothed belt that requires a uniform PLD value.

Further, the total amount of wefts in the longitudinal direction of the belt is 20 to
80% by weight is a multifilament yarn of aramid fibers. The reason for this is that if the amount is less than 20% by weight, the tensile strength of the tooth cloth in the longitudinal direction of the belt is lowered, and tooth breakage is likely to occur during running of the belt under a high load. This is because the rigidity in the driving direction of the multifilament yarn becomes excessively large for the same reason as described above, and it becomes impossible to obtain a canvas having a uniform thickness.

Although 6 nylon and 6.6 nylon yarns have been used for the conventional tooth cloth, the high temperature of the belt (100 to 100
After running for a long time at 140 ° C.), abrasion powder of nylon adhered to the surface of the pulley due to abrasion of the tooth cloth, which accelerated the abrasion of the tooth portion of the belt and caused tooth chipping. Here, when aramid fiber having no clear melting point is used for the tooth cloth, abrasion powder does not stick to the pulley surface, and such a problem is unlikely to occur.

As the warp yarns 7 of the tooth cloth 5, filament yarns of aramid fiber composed of para-aramid fiber and meta-aramid fiber, 6 nylon, 6.6 nylon, 12
It is made of polyamide such as nylon and filament yarn such as polyvinyl alcohol and polyester. It is preferable to use a multifilament yarn in which the filament yarn of aramid fiber is a weft yarn 5 in which the filament raw yarn of para-aramid fiber is bundled so that the rigidity is balanced and the tooth cloth has a uniform thickness.

The above-mentioned tooth cloth 5 is overcoated by applying an adhesive treatment agent comprising a rubber composition obtained by dissolving a rubber composition in an isocyanate substance and a solvent, pre-dried at 60 to 120 ° C, and then 200 to 200 ° C. It is baked at 240 ° C. Alternatively, after the treatment with the RFL solution, the rubber paste may be overcoated. The rubber of the rubber paste used here is preferably one having relatively heat resistance such as hydrogenated nitrile rubber, chlorosulfonated polyethylene, chloroprene, etc., and the same kind of rubber as the tooth portion 2 is the tooth portion 2 and the tooth cloth 5 It is preferable for increasing the adhesive strength with.

Solid content 1 of the adhesive treatment agent adhered to the tooth cloth 5
The adhesion amount of the rubber component or the rubber component or the resin component, which is 2, has a volume of 0.1 to 0.8 with respect to 1 volume of the tooth cloth. As a method for adjusting the amount of the solid matter 12 adhered, in the step of immersing the tooth cloth 5 in the adhesive treatment agent and squeezing it with a roll to dry it, a method of adjusting the squeezing pressure of the tooth cloth 5 or the concentration of the adhesive treatment agent is adjusted. There is a method of adjusting or a method of repeating these steps. In addition, the amount of the solid content adhered is measured by measuring the weight of the tooth cloth 5 and converting it into a volume. That is, the weight of the tooth cloth 5 before and after the adhesion treatment is measured, the weight of the adhesive treatment agent is calculated from the difference, and the specific gravity of each of the tooth cloth 5 and the adhesive treatment agent is converted into a volume.
In this case, the specific gravity of the adhesive treatment agent does not take the solvent into consideration.

With such an amount of adhesion, the adhesive strength at the intersection of the warp and the weft is good, the structure of the tooth cloth is not easily deformed, the abrasion resistance of the belt is improved, and the adhesion is achieved. The hardening of solids does not significantly affect belt life. If it is less than 0.1, the solid content is not sufficiently adhered, the adhesive strength at the intersection of the warp and the weft is weak, and the structure of the tooth cloth easily deforms easily. The wear at the intersection with the weft becomes severe and the wear resistance of the belt is greatly reduced. On the other hand, when it exceeds 0.8, the abrasion resistance of the belt does not largely decrease, but the adhered solid matter is hardened and cracks are easily generated at the root portion of the belt which receives stress concentration.

[0019]

The durability of the belt under high load running is greatly affected by the reinforcement of the root portion of the belt which is subjected to stress concentration. Further, the belt durability during running under high tension is greatly influenced by the wear of the tooth cloth at the bottom of the belt. When the wear of the tooth cloth increases, the reinforcing property of the belt root portion subjected to stress concentration is weakened, and the belt root portion is chipped early. In the toothed belt of the present invention, since the multifilament yarn in which at least the filament raw yarn of the aramid fiber is converged is included in the weft yarn in the belt longitudinal direction, the tooth cloth of the belt tooth bottom portion can be formed even under high tension or high load running. Wear is prevented, and since the root portion of the belt is reinforced for a long time, it is excellent in chipping resistance. Moreover, by adjusting the amount of the solid content of the adhesive treatment agent adhered to the tooth cloth, the adhesive force at the intersection of the warp and the weft is improved to make the tooth cloth structure less likely to be deformed. By preventing the abrasion between the wefts and limiting the amount of the adhesive treatment agent attached, it is possible to reduce the influence of the hardening of the attached rubber and prevent the occurrence of cracks at the tooth root portion where stress is concentrated.

[0020]

EXAMPLES The present invention will be described in detail below with reference to examples. Examples 1 to 4 and Comparative Examples 1 to 2 210 denier 6 nylon filament yarn as the warp for the tooth cloth, and two Conex 20 count yarns and 140 as the weft.
Using a denier urethane elastic yarn stretched and plied, weaving texture (80 warps / 5 cm, 120 wefts /
2/2 twill canvas made of 5 cm) was woven. After weaving,
After the canvas was vibrated in water to shrink it to about half the width at the time of weaving, the rubber compound of Table 1 was dissolved in methyl ethyl ketone, dipped in a treatment liquid containing isocyanate and dried. The treated canvas for tooth cloth having the volume ratio shown in Table 2 was prepared. The canvas used the weft direction in the longitudinal direction of the belt.

[0021]

[Table 1]

[0022]

[Table 2]

Further, as a core wire, about 200 glass fiber filaments having a diameter of about 9 μm which are melt-spun and surface-treated with a silane coupling agent are bundled to form a strand, and the three strands are aligned to form an RFL liquid. It is dipped in the inside, dried at 130 ° C. for 2 minutes, baked at 250 to 300 ° C. for 2 minutes, and then twisted in the Z direction the same number of times as the lower twisted yarn twisted in the S direction at about 12 times / 10 cm. A ply yarn was prepared.

Next, 11 ply-twisted yarns in the S direction are aligned and
The upper twist is a glass fiber cord twisted in the Z direction at a rate of about 8 times / 10 cm, and 11 Z twisted lower twisted yarns are similarly drawn in the same direction, and the glass fiber is twisted 8 times / 10 cm in the S direction. For each RFL liquid, a pair of RFL-treated glass fiber cords having an upper twist direction of S and Z were used. Then, in order to adhere each RFL-treated glass fiber cord to the back, teeth and tooth cloth, a rubber composition is further dissolved in a solvent, immersed in an isocyanate-added overcoat solution, and dried to form a core wire. A fiber cord was produced.

In the production of the toothed belt, the tooth cloth having the composition shown in Table 1 was wound around the mold, the glass fiber cord was spun on the mold, and the rubber sheet made of the rubber compound shown in Table 3 was further wound around the mold. . Subsequently, this was vulcanized, and the obtained vulcanized sleeve was cut into a predetermined width to obtain individual belts. The belt size is 105S8M19
(Belt tooth type: STPD type, number of teeth: 105, belt width: 19.1 mm, tooth pitch: 8 mm).

[0026]

[Table 3]

Each belt was run under high temperature and high tension, and the running time until tooth loss was measured. As shown in FIG. 3, the running tester used here winds a toothed belt 1 between a drive pulley 8 (21 teeth) and a driven pulley 9 (42 teeth), and tensions the back surface of the toothed belt. A pulley 10 (diameter 52 mm) is brought into contact with the belt, the belt temperature is 120 ° C., the rotation speed of the drive pulley is 7,200 rpm,
The driven pulley was caused to run with a load of 5 horsepower and the belt had an initial tension of 30 kgf, and the running time until tooth loss due to wear of the tooth surface was measured. The results are shown in Table 4.

Further, the running time of each of the above belts leading to tooth loss during high load running was measured. The running tester used here is, as shown in FIG. 4, a driving pulley 8 (21 teeth),
Driven pulley 9 (21 teeth) and idler pulley 1
It consists of 3 shafts with 1 (21 teeth), 1 toothed belt is wound around these pulleys, and the number of teeth engaged with the driven pulley 9 is 6
Set on teeth. In this way, the belt 1 is set to the ambient temperature 1
At 20 ° C., the rotational speed of the drive pulley was 6,000 rpm, and the running time until tooth loss was measured at a driven pulley load of 7 horsepower was measured. The results are shown in Table 4.

[0029]

[Table 4]

According to this result, when the solid content of the adhesive treatment agent is reduced, the tooth cloth tends to be worn, and the belt life is shortened. On the other hand, when the solid content of the adhesive treatment agent increases, the tooth cloth is less likely to wear, but the belt life tends to decrease, and cracks occur at the root of the belt due to thermal deterioration of the solid content. Easier to do.

[0031]

As described above, in the toothed belt of the present invention, the weft in the longitudinal direction of the belt as the tooth cloth contains at least aramid fiber, and an appropriate amount of the solid content of the adhesive treatment agent adheres to the tooth cloth. Therefore, not only the material of the tooth cloth but also the tooth cloth structure of the tooth cloth is less likely to be deformed, the abrasion resistance of the belt is greatly improved, and the solid content of the adhesive treatment agent is limited. Since the influence of the hardening of the adhered rubber is reduced, the tooth cloth has sufficient wear resistance during running under high temperature and high tension or under high temperature and high load, which causes deformation due to stress concentration. Since the root portion of the belt, which is easy to reinforce, is reinforced for a long period of time, there is a great improvement in durability due to the greatly improved tooth loss time.

[Brief description of drawings]

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

2 is a cross-sectional view of the toothed belt shown in FIG.

FIG. 3 is a schematic diagram of a running tester used to measure a running time until a tooth chip occurs by running a toothed belt under high temperature and high tension.

FIG. 4 is a schematic diagram of a running tester used for running time of a toothed belt under high temperature and high load and measuring running time until tooth loss.

[Explanation of symbols]

 1 Toothed belt 2 Tooth part 3 Core wire 4 Back part 5 Tooth cloth 6 Weft thread 7 Warp thread 12 Solid content

Claims (1)

[Claims] 1. A toothed belt having a plurality of tooth portions arranged along a length direction and a back portion in which a core wire is embedded, and a tooth belt in which a tooth cloth is coated on a surface of the tooth portion, At least aramid fiber is used for the weft in the longitudinal direction of the belt, and the solid content of the adhesive treatment agent adhered to the tooth cloth is 0.1 to 0.8 per volume of the tooth cloth. A toothed belt characterized in that