JP2006077785A - Power transmission belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a V-ribbed belt, having high thermal bending resistance, excellent wear resistance and sound generation resistance. <P>SOLUTION: This V-ribbed belt 1 is composed of a stretchable part 2 made of cover canvass, an adhesive layer 4 where a core 3 made of a cord is buried, and a compression part 6 made of an elastic substance layer on the lower side thereof. The compression part 6 has a plurality of trapezoidal ribs extending in the longitudinal direction of the belt and having a substantially triangular section. At least the rib side 9 is formed of a rubber composition obtained by blending 5 to 50 wt. parts vegetable soft grains to 100 wt. parts rubber. Preferably the vegetable soft grains are crushed material of at least one kind selected from walnut hull, apricot kernel, peach kernel and corn ear core. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power transmission belt, and more particularly to a power transmission belt having excellent silence and wear resistance, and having high flexibility and heat resistance.

  There is a demand for higher performance and higher performance in the rubber industry field, especially automotive parts. Among rubber products used for automobile parts, there is a power transmission belt, which is widely used for power transmission of auxiliary machines such as an air compressor and an alternator of an automobile.

  In recent years, there has been a strict demand for quietness. In particular, in a driving device, since sounds other than engine sounds are abnormal sounds, there is a demand for measures against belt sound generation. As abnormal noises in the drive unit, slip noise generated under conditions of large rotational fluctuations and high load conditions, and noise generated by adhesive rubber adhering to the groove bottom between ribs as a result of compression rubber causing adhesive wear are pointed out. Has been.

In response to these problems, by embedding a short fiber group such as cotton, nylon, vinylon, rayon, and aramid fiber in the compressed rubber while maintaining the orientation to the belt width, the side pressure resistance of the friction transmission part of the belt is improved. In general, a part of the embedded short fiber is intentionally protruded from the side surface of the belt to aim at a rib portion friction performance and a sound suppression effect due to adhesion. In addition, in order to further improve the effect of the belt, by using an aramid fiber as a short fiber that protrudes on both side wall surfaces of the friction transmission portion, the belt itself is intended to improve durability due to the abrasion resistance unique to the aramid fiber. Transmission belts have also been proposed. (For example, see Patent Document 1)
Japanese Patent Laid-Open No. 1-164839

  However, when short fibers are blended, the heat-resistant flexibility of the belt is deteriorated, and the belt performance is lowered. In addition, since a process of orienting short fibers at a right angle to the longitudinal direction of the belt is required, there is a problem that the belt is expensive.

  As a result of intensive research in view of the above problems, the present invention is proposed, and the object is to have a simple manufacturing process, high wear resistance, low noise, and excellent heat flexibility. It is to provide a power transmission belt.

  The present invention is a power transmission belt characterized in that at least a power transmission surface is composed of a rubber composition in which 5 to 50 parts by weight of vegetable soft particles are blended with 100 parts by weight of rubber.

  The present invention is also the power transmission belt, wherein the plant soft grain is a pulverized product of at least one plant selected from walnut shell, apricot nucleus, peach nucleus and corn head; The power transmission belt is a V-ribbed belt having a compression portion having a stretched portion and a plurality of ribs extending in the circumferential direction of the belt, and a core wire embedded in the longitudinal direction of the belt; The part has a two-layer structure including an inner layer and a surface layer, and the surface layer is formed of the rubber composition.

  In the present invention, at least the friction transmission surface is made of a rubber composition having a specific composition, so that a power transmission belt excellent in heat resistance and flexibility can be obtained while improving silence and wear resistance. In addition, since it is not necessary to orientate plant soft grain in the belt width direction like a short fiber, a manufacturing process becomes simple and can suppress cost. Moreover, by making the plant soft grain into a pulverized product of at least one kind of plant selected from walnut shell, apricot kernel, peach nucleus and corn panicle, it is more excellent in wear resistance and sound resistance. There are features. Furthermore, quietness can be improved by using a solid lubricant together.

  FIG. 1 shows a cross-sectional perspective view of a V-ribbed belt as an embodiment of a power transmission belt according to the present invention. The V-ribbed belt 1 has a configuration in which an extension portion made of a cover canvas 5, an adhesive layer 4 in which a cord 3 made of a cord is embedded, and a compression portion 6 are arranged below the adhesive layer 4. The compression portion 6 has a plurality of trapezoidal ribs having a substantially triangular cross section extending in the belt longitudinal direction. This rib becomes a power transmission part, the rib side surface 9 becomes a power transmission surface, and the vegetable soft grain 8 has the structure which protruded from the rib surface.

  In the present invention, it is essential that at least the power transmission surface, that is, at least the rib side surface 9 of the rib is composed of a rubber composition in which 5 to 50 parts by weight of vegetable soft particles 8 are blended with 100 parts by weight of rubber. However, in FIG. 1, the whole compression part 6 is comprised with this rubber composition.

  The plant soft grain is a plant-derived granule rich in durability and elasticity, and can be obtained, for example, by pulverizing the plant. Specifically, it is desirable to use a pulverized product of at least one plant selected from walnut shell, apricot nucleus, peach nucleus and corn panicle, and the particle size thereof is preferably 50 to 500 μm, more preferably Is 100 to 300 μm. When the particle size is less than 50 μm, there are few protrusions on the rib surface, and the effect on sound resistance is poor. On the other hand, if it exceeds 500 μm, the protrusion to the surface increases, and it is peeled off by friction with the pulley, so that the wear resistance may be lowered. In addition, the vegetable soft grain of a desired particle size distribution can be obtained by sieving using a sieve having an upper limit eye and a lower limit eye of a desired particle size distribution. The hardness is preferably 1.0 to 5.0 (Mou's). If it is less than 1.0, it is inferior to abrasion resistance, and if it exceeds 5.0, it may cause early cracking.

  The amount is 5 to 50 parts by weight per 100 parts by weight of rubber. If it is less than 5 parts by weight, there is no effect on the sound resistance, and if it exceeds 50 parts by weight, there are problems such as difficulty in dispersibility in rubber, and a decrease in wear resistance and belt durability life.

  Of the rubber composition constituting the power transmission surface, the raw rubber is natural rubber, butyl rubber, styrene-butadiene rubber, chloroprene rubber, ethylene-propylene rubber, alkylated chlorosulfonated polyethylene, hydrogenated nitrile rubber, hydrogenated nitrile rubber. And a mixed polymer of an unsaturated carboxylic acid metal salt, a rubber material such as ethylene-α-olefin rubber, or a mixture thereof. Among these, ethylene / α-olefin rubber is preferably used because it has excellent ozone resistance, heat resistance, and cold resistance, is relatively inexpensive, and satisfies the requirement of dehalogenation.

  The ethylene / α-olefin rubber is a copolymer of ethylene and α-olefin (propylene, butene, hexene, octene, etc.) or a copolymer of ethylene, the α-olefin and the non-conjugated diene, specifically Refers to rubbers such as ethylene-propylene rubber (EPM) and ethylene-propylene-diene copolymer (EPDM). Examples of the diene component include non-conjugated dienes having 5 to 15 carbon atoms such as ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, and methylene norbornene. EPDM has the property of being excellent in heat resistance and cold resistance, and a power transmission belt having high heat resistance and cold resistance performance can be obtained. This EPDM preferably has an iodine value of 3 to 40. If the iodine value is less than 3, vulcanization of the rubber composition is not sufficient and problems of wear and adhesion occur, and if the iodine value exceeds 40, the scorch of the rubber composition becomes short and difficult to handle, Heat resistance deteriorates.

  For crosslinking the rubber, sulfur or organic peroxide is used. Specific examples of the organic peroxide include di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, 1.1-t-butylperoxy-3.3.5-trimethylcyclohexane, and 2. 5-di-methyl-2.5-di (t-butylperoxy) hexane, 2.5-di-methyl-2.5-di (t-butylperoxy) hexane-3, bis (t-butylperoxydi-isopropyl) benzene, Examples include 2.5-di-methyl-2.5-di (benzoylperoxy) hexane, t-butylperoxybenzoate, and t-butylperoxy-2-ethyl-hexyl carbonate. This organic peroxide is preferably used alone or as a mixture in the range of 1 to 8 parts by weight with respect to 100 parts by weight of rubber.

  Moreover, you may mix | blend a vulcanization accelerator. Examples of vulcanization accelerators include thiazole, thiuram, and sulfenamide vulcanization accelerators. Specific examples of thiazole vulcanization accelerators include 2-mercaptobenzothiazole, 2-mercaptothiazoline, dibendiazyl, Disulfide, zinc salt of 2-mercaptobenzothiazole, and the like, and thiuram vulcanization accelerators include tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, N, N′-dimethyl. -N, N'-diphenylthiuram disulfide and the like, and as the sulfenamide vulcanization accelerator, specifically, N-cyclohexyl-2-benzothiazylsulfenamide, N, N'-cyclohexyl-2 -Benzothiazylsulfenamide and the like. As other vulcanization accelerators, bismaleimide, ethylenethiourea, and the like can be used. These vulcanization accelerators may be used alone or in combination of two or more.

  Further, by adding a co-agent, it is possible to increase the degree of cross-linking and prevent problems such as adhesive wear. Examples of the crosslinking aid include TIAC, TAC, 1,2 polybutadiene, metal salt of unsaturated carboxylic acid, oximes, guanidine, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, NN′-m- Phenylene bismaleimide, sulfur and the like are usually used for organic peroxide crosslinking, and among them, NN'-m-phenylene bismaleimide is preferable. The blending amount is desirably 0.5 to 10 parts by weight with respect to 100 parts by weight of the rubber component, and if the amount is less than 0.5 parts by weight, the effect of addition is not significant, and if it exceeds 10 parts by weight, the tearing force and the adhesive strength are high There is a problem that it drops.

  Furthermore, by adding a solid lubricant to the rubber composition, sound resistance can be improved. As the solid lubricant, graphite, molybdenum disulfide, mica, talc, antimony trioxide, molybdenum selenide, tungsten disulfide, polytetrafluoroethylene (PTFE), or the like can be used alone or in combination. Preferably, at least one selected from graphite, molybdenum disulfide, and PTFE is used. The solid lubricant is added in an amount of 10 to 100 parts by weight, more preferably 10 to 60 parts by weight with respect to 100 parts by weight of rubber. If the amount is less than 10 parts by weight, the friction coefficient of the belt surface does not change so much. If the inhibitory effect is not remarkable and the other amount exceeds 100 parts by weight, the elongation of the rubber properties is reduced, and the belt life is shortened.

  In addition to the above-mentioned vegetable soft granules, they are used for ordinary rubber compounds such as carbon black and reinforcing agents such as silica, fillers, plasticizers, stabilizers, processing aids, and coloring agents as necessary. Things can be used.

  The adhesive layer 4 can be made of the same rubber composition as that of the compression portion 6, but may be made of another rubber composition. Raw material rubbers and compounding agents as described above can be used, but it is preferable not to mix vegetable soft granules in consideration of adhesiveness.

  The cord 3 can be a twisted cord made of polyester fiber, polytrimethylene terephthalate fiber, polybutylene terephthalate fiber, glass fiber, aramid fiber, or the like. The composition of the glass fiber may be either E glass or S glass (high-strength glass), and is not limited to the thickness of the filament, the number of converging filaments, and the number of strands.

  The core 3 is preferably subjected to an adhesive treatment. For example, (1) After impregnating the untreated cord with a tank containing a treatment liquid selected from an epoxy compound and an isocyanate compound, and pre-dip (2) It was dried by passing it through a drying oven set at 160 to 200 ° C. for 30 to 600 seconds, (3) immersed in a tank containing an adhesive solution made of RFL, and (4) set at 210 to 260 ° C. The film can be stretched by −1 to 3% for 30 to 600 seconds through a stretching heat setting processor to obtain a stretching treatment cord.

  Examples of the isocyanate compound used in this pretreatment liquid include 4,4′-diphenylmethane diisocyanate, tolylene 2,4-diisocyanate, polymethylene polyphenyl diisocyanate, hexamethylene diisocyanate, and polyaryl polyisocyanate (for example, PAPI as a trade name) ) Etc. This isocyanate compound is used by mixing with an organic solvent such as toluene or methyl ethyl ketone.

  In addition, blocked polyisocyanates in which the isocyanate group of the polyisocyanate is blocked by reacting the isocyanate compound with a blocking agent such as phenols, tertiary alcohols, and secondary alcohols can also be used.

  Examples of the epoxy compound include reaction products of polyhydric alcohols such as ethylene glycol, glycerin and pentaerythritol, polyalkylene glycols such as polyethylene glycol and halogen-containing epoxy compounds such as epichlorohydrin, resorcin, bis (4-hydroxy Phenyl) dimethylmethane, phenol. Formaldehyde resin, resorcin. Reaction products with polyhydric phenols such as formaldehyde resins and halogen-containing epoxy compounds. The epoxy compound is used by mixing with an organic solvent such as toluene or methyl ethyl ketone.

  The RFL treatment liquid is a mixture of resorcin and formaldehyde precondensate with rubber latex. In this case, the molar ratio of resorcin and formaldehyde is preferably 1: 2 to 2: 1 in order to increase the adhesive force. . If the molar ratio is less than 1/2, the three-dimensional reaction of resorcin-formaldehyde resin proceeds too much and gels, while if it exceeds 2/1, the reaction between resorcin and formaldehyde does not progress so much, resulting in a decrease in adhesive strength. To do. Examples of the rubber latex include styrene-butadiene-vinylpyridine terpolymer, hydrogenated nitrile rubber, chloroprene rubber, and nitrile rubber.

  The mass ratio of the solid content of the resorcin-formaldehyde initial condensate and the rubber latex is preferably 1: 2 to 1: 8. Maintaining this range is suitable for increasing the adhesive strength. When the above ratio is less than 1/2, the resin content of resorcin-formaldehyde increases, the RFL film becomes hard and dynamic adhesion deteriorates. On the other hand, when the ratio exceeds 1/8, the resin content of resorcin-formaldehyde Therefore, the RFL film becomes soft and the adhesive strength decreases.

  Further, a vulcanization accelerator or a vulcanizing agent may be added to the RFL liquid, and the vulcanization accelerator to be added is a sulfur-containing vulcanization accelerator. Specifically, 2-mercaptobenzothiazole (M ) And salts thereof (for example, zinc salts, sodium salts, cyclohexylamine salts, etc.) thiazoles such as dibenzothiazyl disulfide (DM), sulfenamides such as N-cyclohexyl-2-benzothiazylsulfenamide (CZ) , Thiurams such as tetramethylthiuram monosulfide (TS), tetramethylthiuram disulfide (TT), dipentamethylenethiuram tetrasulfide (TRA), sodium di-n-butyldithiocarbamate (TP), zinc dimethyldithiocarbamate ( PZ) Dithiocarbamine such as zinc diethyldimethyldithiocarbamate (EZ) There are salts and the like.

  Examples of the vulcanizing agent include sulfur, metal oxides (zinc oxide, magnesium oxide, lead oxide), peroxides, and the like, which are used in combination with the above vulcanization accelerator.

  The V-ribbed belt 1 using the core wire 3 preferably has a tensile force required to extend the V-ribbed belt by 2% to 100 to 250 N / rib, more preferably 130 to 210 N / rib. In the case of force, even if belt elongation occurs due to wear of rib rubber or the like, stable tension can be maintained without causing a rapid drop in tension. If it exceeds 250 N / rib, a rapid drop in tension is observed when the belt is stretched, and if it is less than 100 N / rib, the belt tension is greatly lowered due to the core elongation.

  In addition, if the belt is subjected to an initial load of 147N / 5 cords and left to stand in a 100 ° C atmosphere for 30 minutes, the belt contracts when it is heated to give a characteristic of 50-150N / 5 cords. Even if the tension is self-adjustable, a belt with a low belt slip ratio and a long belt life can be obtained without installing an auto tensioner. When the belt shrinkage force is less than 50 N, the performance of adjusting the belt tension is poor and the slip rate tends to increase. Further, when the belt shrinkage force is 150 N, the belt length tends to shrink with time, and the effect of reducing the slip ratio is small.

  The cover canvas 5 is a fiber base selected from woven fabric, knitted fabric, non-woven fabric and the like. Known and publicly used fiber materials can be used. For example, natural fibers such as cotton and hemp, inorganic fibers such as metal fibers and glass fibers, and polyamide, polyester, polyethylene, polyurethane, polystyrene, and polyfluoroethylene. , Organic fibers such as polyacryl, polyvinyl alcohol, wholly aromatic polyester, and aramid. In the case of a woven fabric, these yarns are woven by plain weaving, twill weaving, satin weaving or the like.

  The cover canvas 5 is preferably immersed in the RFL liquid according to a known technique. Further, after immersing in the RFL solution, friction can be performed by rubbing the unvulcanized rubber into the cover canvas 5, or immersion can be performed in a soaking solution in which the rubber is dissolved in a solvent. The RFL solution may be appropriately mixed with a carbon black solution to blacken the treatment, or a known surfactant may be added in an amount of 0.1 to 5.0% by mass.

  As described above, FIG. 1 shows an embodiment in which the entire compression portion 6 is made of the rubber composition. However, in the present invention, at least the power transmission surface of the power transmission belt body (the rib side surface 9 in the case of the V-ribbed belt) is provided. It is mentioned that the rubber composition as described above is an essential condition. Needless to say, all the rubber compositions constituting the belt body can also be constituted by the rubber composition. The following configuration is also possible.

  Another embodiment of the power transmission belt according to the present invention is shown in FIG. The V-ribbed belt 10 has a configuration in which an extended portion made of a cover canvas 15, an adhesive layer 14 in which a cord 13 made of a cord is embedded, and a compression portion 16 are disposed below the adhesive layer 14. The compression portion 16 has a plurality of trapezoidal ribs having a substantially triangular cross section extending in the belt longitudinal direction. The ribs serve as a power transmission portion and the rib side surface 9 serves as a power transmission surface. The rib has a two-layer structure of an inner layer 12 and a surface layer 17, and the surface layer 17 is composed of a rubber composition in which 5 to 50 parts by weight of vegetable soft granules 8 are blended with 100 parts by weight of rubber. The same rubber composition as described above can be used.

  The inner layer 12 can be made of the same rubber composition as that of the surface layer 17, but may be made of another rubber composition. For example, raw material rubbers and compounding agents as described above can be used, but it is preferable not to mix vegetable soft granules in consideration of cost and adhesiveness. The surface layer 17 preferably has a thickness of 0.1 to 0.5 mm. If it is less than 0.1 mm, there is a problem that the effect of the surface layer is diminished by abrasion. The core wire 13, the adhesive layer 14, the cover canvas 15 and the like can be the same as described above.

  The V-ribbed belt is not limited to the configuration shown in FIGS. 1 and 2, and for example, a V-ribbed belt in which no adhesive layer is disposed, a V-ribbed belt in which rubber is exposed without attaching a cover canvas on the back surface, etc. It belongs to the technical scope. Hereinafter, these embodiments will be described. Examples of power transmission belts other than the V-ribbed belt include a V belt.

  A V-ribbed belt 21 shown in FIG. 3 has a configuration in which a back surface is formed of a stretched portion 25 formed of a rubber composition containing short fibers, and a compression portion 26 is disposed below the stretched portion 25. The core wire 23 is embedded in the main body along the longitudinal direction of the belt, and a part thereof is in contact with the extension portion 25 and the remaining portion is in contact with the compression portion 26. The compression portion 25 is provided with a plurality of ribs having a substantially triangular cross section extending in the longitudinal direction of the belt. The ribs serve as a power transmission portion and the rib side surfaces 29 serve as a power transmission surface. The rib has a two-layer structure of an inner layer 22 and a surface layer 27, and the surface layer is composed of a rubber composition in which 5 to 50 parts by weight of vegetable soft particles 28 are blended with 100 parts by weight of rubber.

  A V-ribbed belt 31 shown in FIG. 4 has a stretched portion 35 whose back surface is formed of a rubber composition containing short fibers, an adhesive layer 34 disposed below the stretched portion 35, and a compressed portion 36 below the stretched portion 35. It has the structure which arranged. The core wire 33 is embedded in the main body along the longitudinal direction of the belt, and a part thereof is in contact with the extending portion 35 and the remaining portion is in contact with the adhesive layer 34. The compression portion 36 is provided with a plurality of ribs having a substantially triangular cross section extending in the belt longitudinal direction. The ribs serve as a power transmission portion, and the rib side surfaces 39 serve as a power transmission surface. The rib is composed of a rubber composition in which 5 to 50 parts by weight of vegetable soft granules 38 are blended with 100 parts by weight of rubber.

  In FIGS. 3 and 4, the stretched portion is not composed of a cover canvas, but is formed of a rubber composition containing short fibers. At this time, in order to suppress abnormal noise during back driving, An uneven pattern can be provided. Examples of the concavo-convex pattern include a knitted fabric pattern, a woven fabric pattern, a suede woven fabric pattern, and the like, and most preferably a woven fabric pattern. Moreover, as short fiber, polyester, aramid, nylon, cotton, etc. can be mix | blended as desired, It is desirable to orientate in a belt width direction. As the rubber composition and the core wire constituting the compression part and the adhesive layer, the same ones as described above can be used.

  In the case where the adhesive layer is not disposed as shown in FIG. 3, the core wire 23 is embedded in the belt body in the boundary region between the extension portion 25 and the compression portion 26. At this time, in consideration of the adhesion between the core wire 23 and the belt body, the inner layer 27 of the compression part is preferably composed of a rubber composition that does not contain vegetable soft granules, and the configurations of the inner layer 22 and the surface layer 27 are as follows. It can be set as the same structure as the above-mentioned.

  Next, a method for manufacturing the V-ribbed belt will be described. Although it does not limit as a manufacturing method, For example, there exist the following methods.

  As a first method, first, a member constituting an extension portion and an adhesive rubber sheet constituting an adhesive layer are wound around a circumferential surface of a cylindrical molding drum, and then a cord made of a cord is spirally wound thereon. Then, a compressed rubber sheet constituting a compression part (power transmission part) is wound in order to form an unvulcanized sleeve, followed by vulcanization to obtain a vulcanized sleeve. Next, the vulcanization sleeve is hung on a driving roll and a driven roll and travels under a predetermined tension. Further, the rotated grinding wheel is moved so as to abut on the traveling vulcanization sleeve to compress the sleeve. A surface of 3 to 100 grooves is polished on the surface at a time to form a friction transmission surface. The sleeve thus obtained is removed from the driving roll and the driven roll, the sleeve is hung on the other driving roll and the driven roll, traveled, cut into a predetermined width by a cutter, and finished into individual V-ribbed belts. .

  As a second method, after winding a compression rubber sheet constituting a compression part and an adhesive rubber sheet constituting an adhesive layer around a cylindrical molding drum provided with rib markings on the peripheral surface, spinning a core wire, An unvulcanized sleeve is arranged by winding a member constituting the extension portion. Thereafter, the unvulcanized sleeve is vulcanized while being pressed against the molding drum, whereby a rib is formed on the compression portion. The obtained vulcanized sleeve is formed with ribs. The rib surface is polished if necessary, and cut into a predetermined width to obtain individual V-ribbed belts.

  As a third method, after winding a member constituting an extension portion and an adhesive rubber sheet constituting an adhesive layer on a flexible jacket mounted on a cylindrical molding drum, spinning a core wire thereon Further, the compressed rubber sheets constituting the compression part are sequentially wound endlessly to form an unvulcanized sleeve. Then, the flexible jacket is expanded, and the unvulcanized sleeve is pressed against an outer mold having an inscription corresponding to the rib portion, and vulcanized. The obtained vulcanized sleeve is formed with ribs. The rib surface is polished if necessary, and cut into a predetermined width to obtain individual V-ribbed belts.

  As a fourth method, after forming the first unvulcanized sleeve in which the compressed rubber sheet constituting the compression portion is arranged on the flexible jacket mounted on the cylindrical molding drum, the flexible jacket is used. The first unvulcanized sleeve is expanded and pressed against an outer mold having an inscription corresponding to the rib portion to produce a preform having the rib portion. Then, the inner mold is separated from the outer mold to which the preformed body is in close contact, and then the member constituting the extension part and the adhesive rubber sheet constituting the adhesive layer are arranged on the inner mold, and the core wire is spun. A second unvulcanized sleeve is formed. Then, the flexible jacket is expanded, and the second unvulcanized sleeve is pressed from the inner peripheral side to the outer mold to which the preform is in close contact, and is vulcanized integrally with the preform. Ribs are formed on the obtained vulcanized belt sleeve, but the rib surface is polished if necessary and cut into a predetermined width to obtain individual V-ribbed belts.

  When the compression part of the V-ribbed belt is composed of two layers of the surface layer and the inner layer as shown in FIG. 2 and FIG. 3, a compressed rubber sheet having a two-layer structure of the surface layer and the inner layer is wound, or a compression rubber sheet for the surface layer It is necessary to form an unvulcanized sleeve in which a compression portion having a two-layer structure of a surface layer and an inner layer is disposed by sequentially winding the inner layer and the inner layer compression rubber sheet. At this time, since the rib is formed by polishing in the first method, it is considered that the surface layer exists on the rib crest of the obtained V-ribbed belt, but the inner layer is exposed on the rib side surface and the rib bottom. Therefore, it is desirable to manufacture the V-ribbed belt as shown in FIG. 2 by the second method, the third method, or the fourth method. Further, the V-ribbed belt having no adhesive layer as shown in FIG. 3 can be obtained by manufacturing the above method without arranging an adhesive rubber sheet.

  Hereinafter, the present invention will be described with specific examples.

  In Examples 1 to 4 and Comparative Examples 1 to 4, a rubber composition was prepared according to the formulation shown in Table 1, kneaded with a Banbury mixer, and then rolled with a calendar roll to prepare a compressed rubber sheet. Moreover, about Example 5, 6, the compression rubber sheet which laminated | stacked the rubber composition adjusted according to Table 1 as a surface layer and the rubber composition adjusted according to Comparative Example 4 as an inner layer was produced.

  Next, a V-ribbed belt was produced using the compressed rubber sheet. The configuration of the V-ribbed belt is as follows: a cord made of polyester fiber rope is embedded in the adhesive layer, two plies of rubber cotton canvas are stacked as an extension on the upper side, and the compression part is provided below the other adhesive layer. Three ribs are arranged in the longitudinal direction of the belt. About Example 5, 6, it is comprised so that the thickness of a surface layer may be set to 0.25 mm.

  The manufacturing method of the belt is as follows. First, a cylindrical molding drum provided with rib markings on its peripheral surface, a compressed rubber sheet, an adhesive rubber sheet (excluding vegetable soft granules, solid lubricants and short fibers from the rubber composition in Table 1). The rubber composition) is wound, the polyester rope is spun, a 2-ply cotton canvas with rubber is wound and an unvulcanized sleeve is disposed, and then a vulcanization jacket is inserted on the unvulcanized sheet. Next, the molding mold was placed in a vulcanizing can and vulcanized, and then the tubular ribbed vulcanizing sleeve was removed from the molding drum and cut into a predetermined width to obtain a V-ribbed belt.

  However, in Comparative Example 1, a two-ply cotton canvas with rubber was wrapped around a flat cylindrical mold, and then an adhesive rubber sheet (rubber composition excluding vegetable soft granules, solid lubricant, and short fibers from the rubber composition in Table 1). ) To spin the polyester rope. And after arrange | positioning a compression rubber sheet, the jacket for vulcanization | cure was inserted on this compression rubber sheet. Next, the cylindrical mold was placed in a vulcanizing can and vulcanized, and then the cylindrical vulcanizing sleeve was taken out of the mold. The compressed part of the sleeve was formed into a rib by a grinder and cut into individual belts from the formed body.

  Table 2 shows the results of the heat-flexibility test, 6% slip wear test, and misalignment pronunciation test of each V-ribbed belt thus obtained.

  The running test machine used for the evaluation of the heat-resistant bending test includes a driving pulley (diameter 60 mm), an idler pulley (diameter 50 mm), a driven pulley (diameter 50 mm), a tension pulley (diameter 50 mm), and an idler pulley (diameter 50 mm). Are arranged in order. A V-ribbed belt is hung on each pulley of the test machine, the winding angle of the belt around the idler pulley is 90 °, the ambient temperature is 130 ° C, the drive pulley is rotated at 3300 rpm, and the belt tension is 800 N / rib. After applying a load to the pulley and running for 500 hours, the presence or absence of a crack reaching the core wire was examined.

  In the 6% slip wear test, a driving pulley (diameter 80 mm), a driven pulley (diameter 80 mm), and a tension pulley (diameter 120 mm) are arranged. A V-ribbed belt is hung on each pulley of the test machine, the winding angle of the belt around the tension pulley is 90 °, and under the room temperature conditions, the rotational speed of the driving pulley is 3300 rpm, the torque of the driven pulley is 0.7 kg · m, The belt was run for 24 hours while automatically adjusting the belt tension so that the belt slip ratio was 6%. The belt weight before and after the running test was measured, and the belt weight loss (belt weight before running−belt weight after running) divided by the belt weight before running was calculated as the wear rate.

  In the misalignment sound generation test, a driving pulley (diameter 125 mm), a driven pulley (diameter 125 mm), and a tension pulley (diameter 60 mm) are arranged. Incidentally, the misalignment of 1.8 ° was set with the axial separation of the driving pulley and the driven pulley being 212 mm. Sound generated when the drive pulley is run with a V-ribbed belt hung on each pulley of the testing machine and a load is applied to the drive pulley so that the rotation speed of the drive pulley is 1000 rpm and the belt tension is 6 kgf / rib at room temperature. The level was evaluated. The sound generation level is evaluated in five stages, and “5” indicates the state where the sound generation level is the lowest and no sound can be heard. Note that “3” or higher was defined as a level at which pronunciation is not a concern.

  From the results shown in Table 2, in the examples, excellent results were obtained in heat-resistant flexibility, wear resistance, and sound-proofing property. It was confirmed that Comparative Example 1 in which short fibers were blended was inferior in heat-resistant flexibility although it had high wear resistance and sound resistance. Moreover, the process for orienting the short fibers was necessary, resulting in high costs. In Comparative Example 2 in which a small amount of vegetable soft granules were blended, it was found that the abrasion resistance was satisfactory, but the pronunciation resistance was inferior. On the other hand, it was found that Comparative Example 3 containing a large amount of vegetable soft granules had a high wear rate of 1.5% and the wear resistance was extremely lowered. Further, in Comparative Example 4 in which neither vegetable soft granules nor short fibers were blended, both the wear resistance and sound resistance were in practically unusable levels.

  The V-ribbed belt according to the present invention can be mounted on a drive device for automobiles or general industries.

It is a section perspective view of the V ribbed belt which is the 1st embodiment of the present invention. It is a cross-sectional perspective view of the V-ribbed belt which is the 2nd Embodiment of this invention. It is sectional drawing of the V-ribbed belt which is the 3rd Embodiment of this invention. It is sectional drawing of the V-ribbed belt which is the 4th Embodiment of this invention.

Explanation of symbols

1 V-ribbed belt (power transmission belt)
3 Core wire 4 Adhesive layer 5 Cover canvas 6 Compression part (friction transmission part)
8 Vegetable soft grain 9 Rib side surface (friction transmission surface)

Claims (5)

  A power transmission belt characterized in that at least the power transmission surface is composed of a rubber composition in which 5 to 50 parts by weight of vegetable soft granules are blended with 100 parts by weight of rubber.   2. The power transmission belt according to claim 1, wherein the plant soft grain is a pulverized product of at least one plant selected from walnut shell, apricot nucleus, peach nucleus and corn head.   The power transmission belt according to claim 1 or 2, wherein a solid lubricant is blended in the rubber composition.   4. The power transmission belt according to claim 1, wherein the power transmission belt is a V-ribbed belt having an extension portion and a compression portion having a plurality of ribs extending in the belt circumferential direction and having a core wire embedded along the belt longitudinal direction. The described power transmission belt. The power transmission belt according to claim 4, wherein the compression portion has a two-layer structure including an inner layer and a surface layer, and the surface layer is formed of the rubber composition.

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