JP2000310293A - Toothed belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tooth cloth covered toothed belt, containing a large amount of fluorine contained resin in a form easy to display friction coefficient reducing action in a rubber component to be impregnated and applied on the tooth cloth and improved in abrasion resistance and tooth-chipping resistance. SOLUTION: This toothed belt is constituted by adding, dispersing and adhering 50-400 weight part of fluorine contained resin 6 with respect to 100 weight part of rubber of a rubber component 5 to be impregnated and applied on and in front and back surfaces and the inside of tooth cloth 4, preventing connection of the fluorine contained resin 6 to a first rubber component and connecting directly the first rubber component to a second rubber component constituting a tooth part and a back part. Consequently, a friction coefficient in the middle of belt travelling is continuously reduced as a large amount of the fluorine contained resin is dispersed and adhered in the rubber component on the surface, the back surface of the tooth cloth 4 and a position nearest to a fiber filament surface inside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camshaft of an automobile engine and a drive of an injection pump.
Synchronous conduction of general industrial machines, toothed belts coated with tooth cloth used for small-sized machines that require precise positioning accuracy, especially improved wear resistance and chipping resistance About things.

[0002]

2. Description of the Related Art Toothed belts that simultaneously drive a camshaft, an injection pump, an oil pump, and a water pump of an automobile engine have been used under ever-increasing conditions due to the high output of the engine and the compact engine rules. It has become severe, and further improvement in durability has been required. Synchronous transmission toothed belts used in general industries and transported toothed belts used in small machines that require precise positioning accuracy are also required to extend the belt replacement cycle. I have.

[0003] The failure modes of the toothed belt are roughly classified into cutting of the belt due to fatigue of the cord, and chipping due to overload and wear of the tooth cloth. For cutting due to core wire fatigue, use of aramid core wire or small diameter core wire of high-strength glass, use of hydrogenated nitrile rubber (H-NBR) composition with excellent heat resistance, belt for improvement of engine side This has been improved by the use of an auto-tensioner that keeps the tension constant both at the time of starting and at the time of running, and the occurrence of cutting failure has been reduced.

[0004]

[0005] However, the occurrence of tooth chipping has been taken, although measures such as the use of high-strength type tooth cloth using nylon 6-6 or aramid fiber have not been taken yet. . Therefore, in order to further improve the chipping resistance of the toothed belt coated with the tooth cloth, it is considered effective to reduce the friction coefficient of the tooth cloth surface. EP0
662571B1 proposes a toothed belt in which a polymer matrix layer containing a fluororesin is sprayed or coated on the outside of a woven fabric layer of a tooth cloth. This fluororesin is bound without a boundary layer in a special polymer matrix. Then, the polymer matrix is bonded to the tooth cloth. However, because the fluoropolymer is tightly bound to the polymer matrix,
There has been a problem that the fluororesin remains surrounded by the matrix and the effect of reducing the friction coefficient by the fluororesin cannot be sufficiently exhibited. In addition, due to material limitations of the polymer matrix, the amount of fluororesin that can be contained is small,
There has been a problem that the thickness of the polymer matrix layer is also reduced, and the improvement of tooth chipping resistance by the fluororesin is not sufficient.

In Japanese Patent Application Laid-Open No. Hei 7-151190, the surface and the interior of a tooth cloth are impregnated with a rubber composition containing a fibrous fluororesin, and the back surface of the tooth cloth is applied to a rubber layer of a belt body via an adhesive layer. Coupling toothed belts have been proposed. The reason why the fluororesin in the rubber composition is fiberized by the kneading step or the like is to prevent the fluororesin in the rubber composition from becoming foreign matter and reducing the strength of the rubber composition. However, there has been a problem that the fluororesin fiberized in the rubber composition has few opportunities to be exposed on the friction surface, and the effect of reducing the friction coefficient by the fluororesin is not sufficient. Also, in order to maintain the strength without fibrillating the fluororesin to form foreign matter, it can contain only about 1 to 30 parts by weight of the fluororesin per 100 parts by weight of the rubber impregnated in the tooth cloth, There is a problem that the improvement of the tooth chipping resistance is not sufficient.

The present invention has been made in view of the above-mentioned problems, and comprises a rubber composition which is impregnated and coated on a tooth cloth, in which a large amount of a fluorine resin is contained in a form in which the effect of reducing the coefficient of friction is easily exhibited. An object of the present invention is to provide a toothed belt coated with a tooth cloth with improved wear resistance and tooth chipping resistance.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a method of fabricating a warp or a weft yarn which comprises a fluororesin which is not bonded to a rubber composition to be impregnated and coated on a tooth cloth. By dispersing and dispersing to a portion close to the filament, it is possible to contain a large amount of fluororesin, and the opportunity for the fluororesin to be exposed to the friction surface is increased, and the effect of reducing the friction coefficient by the fluororesin can be surely exhibited. It was completed with the knowledge that

[0008] That is, a first invention is a toothed belt having a plurality of teeth arranged at predetermined intervals along a longitudinal direction, and a back having a core wire embedded therein, the surface of which is covered with a tooth cloth. In the above, the first rubber composition is impregnated and coated so that the front and back surfaces and the inside of the tooth cloth are in communication with each other, and a fluororesin is bonded to the first rubber composition in the first rubber composition. Wherein the first rubber composition and the second rubber composition forming the teeth and the back are integrated by vulcanization and pressurization. When the first rubber composition is impregnated and coated so that the front and back surfaces and the inside of the tooth cloth are in communication with each other, the fluororesin not bonded to the first rubber composition is entangled with the filament constituting the tooth cloth. And a large amount of fluororesin can be contained.

A second invention provides a toothed belt having a plurality of teeth arranged at predetermined intervals in a longitudinal direction and a back having a core wire embedded therein, the surface of the teeth being covered with a tooth cloth. In the front and back and inside of the tooth cloth, a compound in which 50 to 400 parts by weight of a fluororesin is added to and dispersed in 100 parts by weight of the rubber in the first rubber composition, or a powdery fluororesin, 10 per 100 parts by weight of rubber in the first rubber composition
The fluororesin is not bonded to the first rubber composition, and the first rubber composition and the second part constituting the teeth and the back part are not bonded to the first rubber composition. It is characterized by being directly bonded to a rubber composition. Preferably, the composition is adhered in an amount of 7 to 40% by weight based on the weight of the tooth cloth before the adhesion treatment, and more preferably, the fluororesin is powdered to have an average powder diameter of 0.1%.
５００500 μm. When the fluororesin which does not bind to the first rubber composition is contained in a large amount to be 50 to 400 parts by weight or 100 to 250 parts by weight based on 100 parts by weight of the first rubber composition, the frictional surface of the fluororesin may be reduced. Increases the degree of exposure, and exerts the effect of reducing the coefficient of friction.

[0010] In the first and second inventions, the yarn constituting the tooth cloth may be provided with an adhesive component with the first rubber composition, or the first rubber composition of the tooth cloth may have the above-mentioned property. It is preferable that a friction coefficient reducing agent other than a fluororesin is added, or that the first rubber composition of the tooth cloth and the second rubber composition of the tooth portion and the back portion are the same. When the tooth cloth contains an adhesive component with the first rubber composition,
The first rubber composition holding the fluororesin penetrates into the inside of the filament constituting the tooth cloth, and as a result, a large amount of the fluororesin can be entangled with the tooth cloth. When a friction coefficient reducing agent other than the fluororesin is added, the effect of reducing the friction coefficient by both the fluororesin and the friction coefficient reducing agent is exhibited. When the first rubber composition of the tooth cloth and the second rubber composition of the belt body are made of the same quality, even if the first rubber composition of the tooth cloth contains a large amount of unbonded fluororesin, the first rubber composition And the second rubber composition can be secured.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged sectional view of a tooth cloth,
FIG. 2 is a perspective view showing the structure of the toothed belt. In FIG. 2, a toothed belt A includes a plurality of teeth 3 arranged at predetermined intervals along a longitudinal direction, and a back 2 continuous with the teeth 3.
The structure has a core wire 1 embedded in a back portion 2 and a tooth cloth 4 coated on the surface of the tooth portion 2. The tooth cloth 4 is formed by weaving a weft 7 extending in the longitudinal direction of the belt and a warp 8 extending in the width direction of the belt.

As shown in FIG. 1, a first rubber composition 5 mainly composed of rubber is impregnated and coated on the front, back and inside of a tooth cloth 4 formed by weaving a weft 7 and a warp 8. A powdery fluororesin 6 is dispersed and disposed inside the rubber composition 5. And the fluororesin 6 and the rubber composition 5 are not bonded, and the gap 10 is formed in all or a part of the periphery. The teeth 3 and the back 2 covered with the tooth cloth 4 are formed of a second rubber composition 9 mainly composed of rubber.

The fluororesin 6 and the first rubber composition 5 are not chemically bonded to each other while the fluororesin 6 remains in a powdery state. Therefore, when the tooth cloth 4 is subjected to a frictional action, the fluororesin 6 contained in the first rubber composition 5 is largely exposed to the friction surface, and effectively exerts a friction coefficient reducing action. Further, when the fluororesin 6 is powdered, a large amount of the fluororesin 6 can be blended so as to be entangled with the weft 7 and the warp 8 constituting the tooth cloth 4, and the fluororesin 6 can be supplied in a large amount to the friction surface of the tooth cloth 4.
Further, the first rubber composition 5 of the tooth cloth 4 is chemically bonded to the second rubber composition 9 of the belt body (tooth portion 3 and back portion 2) by heat vulcanization or the like. Even if a large amount of powdery fluororesin 6 is blended with 5, the interface 11 between the tooth cloth 4 and the belt body is firmly joined.

An electron micrograph near the tooth cloth shown in FIG.
The state in which the fluororesin 6 is entangled with the tooth cloth 4 will be described. According to the photograph, the first rubber composition 5 is impregnated into the inside of the weft 7 of the tooth cloth, that is, the inside of the filament. Therefore, the powdery fluororesin 6 gathers around the weft 7 and is entangled. This fluororesin 6 is not bonded to the surrounding first rubber composition 5 and has a gap. Therefore, the fluororesin 6 is exposed without being restricted by the first rubber composition 5, and is effectively supplied to the friction surface. Returning to FIG. 1, since the friction surface of the tooth cloth 4 is a fiber on the surface of the tooth cloth 4, a large amount of unrestrained fluororesin 6 entangled with the fiber of the tooth cloth 4 effectively reduces the friction coefficient of the tooth cloth 4. .

The weft 7 and the warp 8 constituting the tooth cloth 4 are made of nylon, aramid, polyester,
Any or a combination of polybenzoxazole fibers can be employed. The form of the fiber may be any of a filament yarn and a spun yarn, and may be a twisted yarn of a single composition, a mixed twisted yarn, or a mixed spun yarn. A spun yarn or a yarn in which filaments are gathered to such an extent that the first rubber composition 5 can be impregnated inside the fiber is preferable. In addition, since the aramid fiber or the polybenzoxazole fiber is a fiber having a low coefficient of friction itself, by including at least the weft 7 in the belt longitudinal direction, the tooth chipping resistance is improved.

The woven structure of the tooth cloth can include a large amount of the fluororesin 6 in any of a twill weave, a satin weave, and a plain weave. First rubber composition 5 in which fluororesin 6 is dispersed
In order to effectively impregnate and coat the tooth cloth 4, the thickness and density of the fibers are selected so that the first rubber composition 5 is in communication with each other on the front and back surfaces and inside the tooth cloth 4.

First rubber composition 5 impregnated and coated on tooth cloth 4
The rubber of the same kind as that of the rubber of the second rubber composition 9 constituting the belt body of the tooth part and the back part is selected. Depending on the use environment, automotive engines and toothed belts for various types of engines include, as rubbers of the first rubber composition and the second rubber composition, hydrogenated nitrile rubber (H-NBR) having heat resistance and oil resistance, and chloroprene. (CR), chlorosulfonated polyethylene (CSM) and the like are used. Using the second rubber composition using any rubber for the back and teeth,
In addition, a toothed belt using tooth cloth treated as a treatment liquid by adding a first rubber composition using the same type of rubber to a rubber paste and adding a fluororesin as a treatment liquid, in the case of any of the rubber compositions, a fluororesin-added Great effect. However, other rubbers used for toothed belts used in other general industrial machines, such as acrylonitrile butadiene copolymer (N
BR), ethylene propylene diene monomer (EPD)
M), ethylene propylene copolymer (EPR), styrene butadiene copolymer (SBR), isoprene rubber (I
R), natural rubber (NR), acrylic rubber, fluoro rubber,
Similarly, in any case such as silicon rubber, the use of a fluororesin for the treatment of tooth cloth has the effect of improving the life of missing teeth. In particular, the hydrogenated nitrile rubber preferably has a hydrogenation rate of 80% or more, and more preferably 90% or more, in order to exhibit heat resistance and ozone resistance characteristics. A hydrogenated nitrile rubber having a hydrogenation rate of less than 80% has extremely low heat resistance and ozone resistance.

In the first rubber composition, carbon black, zinc white, stearic acid, a plasticizer, an antioxidant and the like are added to the rubber as a compounding agent, and sulfur and an organic peroxide are added as a vulcanizing agent. It is added. The content of these compounding agents, vulcanizing agents, and the like may be determined according to a conventional method, and is not particularly limited.

The fluororesin 6, which is not bonded to the rubber of the first rubber composition impregnated and coated on the tooth cloth 4, is polytetrafluoroethylene, polytrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene. -One or more of perfluoroalkoxyethylene copolymer and tetrafluoroethylene-ethylene copolymer. These fluororesins 6 are powdered by granulation or crushing, and have an average particle diameter of 500 μm or less. The effect of attaching the fluororesin 6 to a position close to the surface of the fiber filaments constituting the weft and the warp of the tooth cloth 4 to reduce the friction coefficient at the time of engagement between the toothed belt and the pulley and extending the life of the belt is as follows. The effect increases as the ratio of the number of fluorine atoms in the film increases. Therefore, assuming the same amount of adhesion to the tooth cloth, the fluororesin 6
Among them, polytetrafluoroethylene is the most effective in reducing the friction coefficient and has a long tooth chipping life. However, other fluororesins also have an effect substantially in proportion to the ratio of the number of fluorine atoms in the molecule. The form of the powder of the fluororesin is not particularly limited, but is dispersed in the rubber composition in a state of a powder pulverized or granulated to an average diameter of 500 μm or less. If the diameter exceeds 500 μm, the surface area of the fluororesin 6 in the belt decreases and the effect is reduced. When the diameter is 0.1 μm, the powder is excessively dispersed, and the chance of exposure to the friction surface is reduced. In particular, a fluororesin having a small particle diameter of 3 to 30 μm obtained by emulsion polymerization, suspension polymerization or the like has a large effect of reducing the friction coefficient.

As a specific method of attaching the fluororesin 6 to the tooth cloth 4, the following method can be exemplified. After kneading the first rubber composition, the first rubber composition is mixed with methyl ethyl ketone (ME
K), and dissolved in a solvent such as toluene, and the fluororesin 6 was added in an amount of 50 to 400 with respect to 100 parts by weight of the rubber in the first rubber composition.
A part by weight is added and uniformly dispersed to obtain a treatment liquid. The cloth 4 is immersed in the treatment liquid and dried, and the amount of the mixture of the fluororesin 6 and the rubber composition is set to 7 based on the weight of the cloth 4 before the immersion treatment.
It is used for producing a belt as about 40% by weight. In addition, a dispersion of fluororesin 6 in water is mixed in a resorcinol-formalin rubber latex mixture, and the fabric for a tooth cloth is immersed, dried and heat-treated, and the surface of the tooth cloth, the back side, and the surface of the fiber filament inside the tooth cloth are mixed. Can be used.

In order for the effect of improving the performance of the toothed belt to travel under high load conditions to be recognized as the amount of fluorine added, 50 parts by weight of the fluororesin 6 is required for 100 parts by weight of the rubber in the rubber composition. The effect is small if no part is added. On the other hand, when the amount of the added fluororesin exceeds 400 parts by weight based on 100 parts by weight of the rubber of the rubber composition, the adhesiveness of the tooth cloth is reduced, and the belt performance is reduced. The preferred addition amount is rubber 1
More than 100 parts by weight and not more than 250 parts by weight with respect to 00 parts by weight.

As a method of measuring the amount of the composition comprising the fluororesin powder and the rubber composition adhered to the tooth cloth,
The mass of the pretreated tooth cloth is weighed and the mass (W1) is measured. Next, the pretreated tooth cloth is immersed in the treatment solution in which the above-mentioned composition is dissolved, and then the cloth is put into an oven and dried until the weight becomes constant, and the final weight (W2) is measured. , ((W2−W1) / W1) × 100 (%).

Further, the amount of adhesion of the compound of the fluororesin and the rubber composition is at least 7 with respect to the weight of the tooth cloth before the impregnation treatment.
If it is not more than 10% by weight, the adhesive strength is low and the total amount of the adhered amount of the fluororesin 6 is small, so that the effect of improving the belt performance is small,
If the content exceeds 0% by weight, the rigidity of the tooth cloth increases, and it becomes difficult to mold the tooth profile during vulcanization. The preferred amount of adhesion is 15 to 25% by weight based on the weight of the tooth cloth before the impregnation treatment.

Further, together with the fluororesin 6, one or more of molybdenum disulfide, layered graphite, glass beads, ceramic powder, spherical phenol resin powder and aramid, polyamide, polyester, polybenzoxazole, fiber cut yarn or powder are used. It is preferable to add the rubber composition dissolved in a solvent to the rubber paste and mix and disperse the mixture. Then, after immersing the tooth cloth and drying it, it is preferable to adhere to the tooth cloth by vulcanization at the time of producing the belt and to integrate it with the belt body. By further adding these friction coefficient reducing agents, the effect of reducing the friction coefficient is enhanced as compared with using the fluororesin 6 alone, and the durability of the belt is further improved. In particular, molybdenum disulfide and graphite having a layered structure have been conventionally used as a sliding agent. When used together with the fluororesin 6, the stress applied to the bottom of the belt tooth due to friction at the time of engagement between the pulley and the belt is further reduced. .

Further, the adhesiveness of the rubber composition to be impregnated and coated on the tooth cloth 4 is improved, and a fluororesin is adhered to a portion of the tooth cloth 4 close to the surface of the warp yarn. In order to obtain an improved bonding property, it is preferable that the fiber used for the tooth cloth 4 is subjected to a treatment for providing an adhesive component. The following method is preferred as the method for providing the adhesive component.

The untreated tooth cloth is immersed in a pretreatment liquid containing an isocyanate compound, an epoxy compound, or an RFL solution at room temperature for 0.5 to 30 seconds, and then placed in an oven adjusted to 150 to 190 ° C. for 2 to 5 minutes. Through and dry.

Examples of the isocyanate compound used in the above pretreatment liquid include 4,4'-diphenylmethane diisocyanate, tolylene 2,4-diisocyanate, polymethylene polyphenyl diisocyanate, hexamethylene diisocyanate, and polyaryl polyisocyanate (for example, as trade names). PAPI). This isocyanate compound is also used by being mixed with an organic solvent such as toluene and methyl ethyl ketone. Further, a blocked polyisocyanate in which an isocyanate group of the polyisocyanate is blocked by reacting a blocking agent such as a phenol, a tertiary alcohol, or a secondary alcohol with the above isocyanate compound can also be used.

Examples of the epoxy compound used in the pretreatment liquid include polyhydric alcohols such as ethylene glycol, glycerin and pentaerythritol, and reaction of a polyalkylene glycol such as polyethylene glycol with a halogen-containing epoxy compound such as epichlorohydrin. And products of reaction with polyhydric phenols such as resorcin, pis (4-hydroxyphenyl) dimethylmethane, phenol, formaldehyde resin, resorcin and formaldehyde resin, and halogen-containing epoxy compounds. The epoxy compound is used by being mixed with an organic solvent such as toluene and methyl ethyl ketone.

Further, the RFL solution used in the pretreatment solution is a mixture of an initial condensate of resorcinol and formalin, and at least one rubber latex selected from nitrile rubber latex and hydrogenated nitrile rubber latex, In this case, it is preferable that the molar ratio of resorcinol to formalin be 3/1 to 1/3 in order to increase the adhesive strength. The initial condensate of resorcinol and formalin is mixed with rubber latex such that the resin content is 5 to 100 parts by weight with respect to 100 parts by weight of rubber of rubber latex, and the total solid concentration is 5 to 100 parts by weight. Adjusted to 40% concentration.

The fluororesin 6 of the present invention is in a state of being dispersed in the rubber composition and does not directly bond to and adhere to the fibers of the untreated tooth cloth. Therefore, after the fiber is treated in advance with any of the adhesive components of RFL, epoxy resin, and isocyanate by the above-described method, a rubber composition in which a fluororesin is dispersed is laminated, and the rubber of the belt body is subjected to pressure vulcanization. To firmly adhere the fiber and the belt body. Alternatively, an adhesive component such as an epoxy resin or an isocyanate may be added to a treatment solution obtained by dissolving a blend of a fluororesin and a rubber composition in a solvent to directly adhere to an untreated tooth cloth. This is because the rubber composition containing the fluororesin adheres to the fiber surface of the woven fabric for a tooth cloth via an epoxy resin or isocyanate adhesive component layer. Although the fluororesin does not directly adhere to the rubber composition and the fiber surface, the fluororesin is dispersed in the rubber composition and exists on the very close surface of the fiber, so that the stress applied to the tooth bottom due to friction during belt running is reduced. When the tooth cloth is reduced, the fluorine resin works effectively and contributes to the improvement of the durability of the belt.

The core 1 used for the belt having the fluororesin 6 adhered to the tooth cloth 4 is not limited. 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 converging filaments, and the number of strands. Further, the present invention is not limited to a sizing agent, an RFL, an overcoat agent, and the like used as an adhesive treatment agent and a protective material for a glass filament during bending. 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.

The toothed belt having the above-described configuration is the first type.
Friction during running of the belt by dispersing a large amount of fluororesin powder that does not bind to the rubber composition in the rubber composition at a position very close to the surface of the tooth cloth, the back surface, and the surface of the fiber filament inside the toothed belt. The coefficient is continuously reduced during running to improve tooth chipping resistance. The shape of the fluororesin differs depending on the pulverization method or the granulation method, but any shape may be used, and it is not necessary that the fluororesin be polytetrafluoroethylene having a property of forming a fiber by mixing and kneading in rubber. Rather, a fluororesin having a small particle size that is difficult to form fibers has a greater effect. By adding a large amount of the rubber composition to the rubber paste dissolved in a solvent, the fluororesin is present in a large amount in the paste rubber in a state of being dispersed in the rubber composition, and the tooth cloth is immersed, dried, and added. Upon vulcanization, the adhesive strength to the belt body is increased by bonding the adhesive components such as isocyanates, epoxy resin, RFL, etc., which have been previously treated on the surface of the filament in the tooth cloth, to the rubber composition excluding the fluororesin, and the strong adhesive force to the tooth cloth Can be obtained. In this case, the fluororesin is not directly bonded to the rubber composition, but the effect is continuously exerted during running due to the presence of a large amount at a position very close to the surface of each single filament of warp and weft constituting the tooth cloth. I do.

[0033]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples, and can be appropriately changed without departing from the object.

EXAMPLE A 100% by weight of MDI was mixed with toluene 9
It was immersed in a pretreatment liquid dissolved in 00 parts by weight, dried at 120 ° C., and then heat-treated at 180 ° C. for 2 minutes. Further, after dissolving the rubber composition of Table 2 in MEK (in the case of H-NBR) and toluene (in the case of other rubber components), a fluororesin and other molybdenum disulfide, graphite, glass beads and the like are added as additives. The mixture was added and mixed to obtain a uniform processing solution having a solid content of about 10%. The pretreated woven fabric for a tooth cloth was immersed in the treatment liquid and dried to obtain a treated tooth cloth material for forming a belt.

[0035]

[Table 1]

[0036]

[Table 2]

Next, the above-mentioned tooth cloth is wound around a mold for forming a belt, and a core wire (glass fiber, 1.2 mm diameter) bonded to the SZ twisted pair of RFL and isocyanate is applied at a constant pitch (1.4 mm). ), Was wound around the spiral with a constant tension, and a 2.5 mm rubber sheet having the same composition as in Table 2 was attached thereon. Further, the mixture is put into a vulcanizing can to form a tooth profile by a normal press-fitting method.
After partial pressure vulcanization, the back surface of the belt was polished to a certain thickness and cut to a certain width to obtain a belt with running teeth. The composition of each material of the produced belt is as shown in Tables 3 to 5.

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

The size of the created belt is 15 belt widths.
mm, belt tooth shape Y (8.0 mm pitch), number of teeth 105
And usually displayed as 105Y15. As a running test device, the number of driving pulley teeth was 19, the number of driven pulley teeth was 38, the driving pulley rotation speed was 7200 rpm, the driven pulley load was 7.5 kW, the initial tension was 350 N, and the atmosphere temperature was 130 ° C. A durability test under load, high tension, and high temperature conditions was performed. Tables 3 and 4 show the life time and failure mode in the durability test. Further, using the same belt, the multi-axial bending tester shown in FIG.
° C, drive pulley rotation speed 5500 rpm, belt tension 20
The vehicle was run at 0 N (axial load: 40 kg), and the life times shown in Tables 3 and 4 were obtained.

According to Examples 1 to 9 and Comparative Examples 1 to 3, 50 parts by weight of PTFE was added to 100 parts by weight of the rubber in the rubber composition.
４００400 parts by weight of the composition was impregnated and coated on the tooth cloth,
Similarly, the rubber component integrated with the tooth rubber and the back rubber has improved durability. According to Examples 7 and 8 and Comparative Example 4, the average particle diameter of the PTFE powder is preferably small, and if it exceeds 500 μm, the effect of improving the durability is reduced. According to Example 15, the effect of improving the durability was observed in the case where the composition was applied in an amount of 7% by weight or more based on the weight of the tooth cloth before treatment. Further, according to Examples 4 to 6, a synergistic effect in improving the durability is obtained in the case where PTFE is added with molybdenum disulfide, graphite, and aramid fiber powder.

Example B Examples 16 to 23 and Comparative Examples 6 to 8 in which the rubber composition impregnated and coated on the tooth cloth, the tooth rubber and the rubber composition of the back rubber are rubber components other than H-NBR. , A running test was conducted to confirm the effect. However, the running conditions were changed to 80 ° C. for the three-axis running and 60 ° C. for the multi-axis running test in consideration of the heat resistance of the rubber composition. The running test results are shown in Table 5. Even if the rubber composition such as chloroprene (CR), chlorosulfonated polyethylene (CSM), styrene-butadiene copolymer (SBR), acrylonitrile-butadiene copolymer (NBR), EDDM, EPR, or the like is changed to a rubber composition, the examples are not limited to the examples. As in the case of 1, it is effective in improving the life.

[0044]

According to the present invention having the above-described structure, the powder of the fluororesin which does not bind to the rubber composition impregnated and coated on the tooth cloth is placed in a position very close to the tooth cloth surface of the toothed belt, the back surface and the inner surface of the fiber filament. By dispersing and adhering a large amount of the rubber composition to the rubber composition, the friction coefficient during the running of the belt is continuously reduced during the running, and the effect of improving the tooth chipping resistance is exhibited.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing a structure of a main part of a toothed belt of the present invention.

FIG. 2 is a perspective view showing the entire structure of the toothed belt of the present invention.

FIG. 3 is a scanning micrograph showing a state of a fluororesin entangled in the vicinity of a fiber of a tooth cloth.

FIG. 4 is a schematic view showing an apparatus for measuring durability of a toothed belt.

FIG. 5 is a schematic view showing an apparatus for measuring durability of a toothed belt.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 core wire 2 back part 3 tooth part 4 tooth cloth 5 1st rubber composition 6 fluororesin 7 weft 8 warp 9 2nd rubber composition 10 gap 11 boundary surface

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazuhiro Takeda 4-1-1-21 Hamazoedori, Nagata-ku, Kobe-shi, Hyogo Inside Mitsuboshi Belting Co., Ltd. (72) Inventor Yasunori Nakai 4-1-1 Hamazodori, Nagata-ku, Kobe-shi, Hyogo No. 21 Mitsuboshi Belting Co., Ltd.

Claims (8)

[Claims] 1. A toothed belt having a plurality of teeth arranged at predetermined intervals along a longitudinal direction and a back having a core wire embedded therein, wherein the surface of the teeth is covered with a tooth cloth. The first rubber composition is impregnated and coated such that the front and back surfaces and the inside of the first rubber composition are in communication with each other, and the fluororesin is dispersed in the first rubber composition without being bonded to the first rubber composition. A toothed belt, wherein the first rubber composition and the second rubber composition forming the teeth and the back are integrated by vulcanization and pressurization. 2. A toothed belt having a plurality of teeth arranged at predetermined intervals along a longitudinal direction and a back having a core wire buried therein, wherein a surface of the teeth is covered with a tooth cloth. A composition prepared by adding 50 to 400 parts by weight of a fluororesin to 100 parts by weight of the rubber in the first rubber composition and dispersing the same is adhered to the front, back, and inside of the first rubber composition. A toothed belt, wherein the first rubber composition and the second rubber composition forming the tooth portion and the back portion are directly bonded without being bonded to a material. 3. A toothed belt having a plurality of teeth arranged at predetermined intervals along a longitudinal direction and a back part having a core wire embedded therein, wherein the surface of the teeth is covered with a tooth cloth. A compound obtained by adding and dispersing 100 to 250 parts by weight of a fluororesin to 100 parts by weight of the rubber in the first rubber composition is adhered to the front and back surfaces and the inside of the first resin composition.
A toothed belt, wherein the first rubber composition and the second rubber composition forming the tooth portion and the back portion are directly bonded without being bonded to the rubber composition. 4. The toothed belt according to claim 2, wherein the composition is applied in an amount of 7 to 40% by weight based on the weight of the tooth cloth before the application treatment. 5. The toothed belt according to claim 4, wherein the fluororesin is in a powder form, and the powder has an average diameter of 0.1 to 500 μm. 6. The yarn constituting the tooth cloth is provided with an adhesive component for bonding to the first rubber component.
The toothed belt as described. 7. The toothed belt according to claim 1, wherein a friction coefficient reducing agent other than the fluororesin is added to the first rubber component of the tooth cloth. 8. The first rubber composition of the tooth cloth and the second rubber composition of the tooth portion and the back portion are the same.
Or, the toothed belt according to 2 or 3.