JP2020122581A - Friction transmission belt - Google Patents

Abstract

To provide a friction transmission belt that has very high noise suppressing effect when submerged, and also has excellent durability.SOLUTION: A friction transmission belt B comprises a rubber layer 11 constituting a pulley contact portion on a belt inner peripheral side. The rubber layer 11 is formed of a rubber composition comprising a crosslinked rubber component, lamellar silicate, and aramid powder. The rubber composition is blended with a reinforcement material of carbon black. In the rubber composition, the content of the reinforcement material to the rubber component 100 pts.mass is higher than the sum of the lamellar silicate content and the aramid powder content.SELECTED DRAWING: Figure 1

Description

The present invention relates to a friction transmission belt.

It has been proposed to incorporate various materials in the compression rubber layer of the friction transmission belt for the purpose of reducing the generation of noise when the belt is running. For example, Patent Document 1 discloses that a rubber composition forming a compressed rubber layer of a V-ribbed belt contains a layered silicate for the purpose of reducing the generation of abnormal noise when exposed to water. Patent Document 2 discloses that aramid powder is contained in a rubber composition forming a compressed rubber layer of a V-ribbed belt for the purpose of reducing noise.

JP, 2010-196743, A International Publication No. 2009/093465

However, the present effect of reducing the generation of abnormal noise when exposed to water is not satisfactory. In addition to the problem of sound, it is desired to improve the durability of the friction transmission belt.

An object of the present invention is to obtain a very high noise reduction effect when the friction transmission belt is exposed to water and to obtain excellent durability.

The present invention is a friction transmission belt having a rubber layer forming a pulley contact portion on the inner peripheral side of the belt, wherein the rubber layer contains a crosslinked rubber component, a layered silicate, and an aramid powder. In the rubber composition, the content of the reinforcing material relative to 100 parts by mass of the rubber component is the layered silicate of the layered silicate. It is more than the sum of the content and the content of the aramid powder.

According to the present invention, the rubber composition forming the rubber layer forming the pulley contact portion on the inner peripheral side of the belt contains the layered silicate and the aramid powder, so that the water content can be improved as shown in Examples below. It is possible to obtain a very high effect of reducing the generation of abnormal noise and also to obtain excellent durability.

FIG. 3 is a perspective view of the V-ribbed belt according to the first embodiment. FIG. 3 is a cross-sectional view of one V-ribbed belt of the V-ribbed belt according to the first embodiment. It is a longitudinal cross-sectional view of a belt molding die. It is a longitudinal cross-sectional enlarged view of a part of the belt mold. FIG. 5 is a first explanatory view of the method for manufacturing the V-ribbed belt according to the first embodiment. FIG. 6 is a second explanatory view of the method for manufacturing the V-ribbed belt according to the first embodiment. FIG. 6 is a third explanatory view of the method for manufacturing the V-ribbed belt according to the first embodiment. FIG. 8 is a fourth explanatory view of the method for manufacturing the V-ribbed belt according to the first embodiment. It is a figure which shows the pulley layout of the accessory drive belt transmission of a motor vehicle. 6 is a perspective view of a V-ribbed belt according to a second embodiment. FIG. FIG. 6 is a cross-sectional view of one V-ribbed belt of a V-ribbed belt according to a second embodiment. FIG. 9 is a first explanatory view of the method for manufacturing the V-ribbed belt according to the second embodiment. FIG. 9 is a second explanatory view of the method for manufacturing the V-ribbed belt according to the second embodiment. FIG. 7 is a perspective view of a V-ribbed belt according to a third embodiment. FIG. 9 is a sectional view of one V-ribbed belt of a V-ribbed belt according to a third embodiment. FIG. 9 is a first explanatory view of the method for manufacturing the V-ribbed belt according to the third embodiment. FIG. 9 is a second explanatory view of the method for manufacturing the V-ribbed belt according to the third embodiment. FIG. 9 is a third explanatory view of the method for manufacturing the V-ribbed belt according to the third embodiment. It is a perspective view of the low edge type V belt concerning other embodiments. It is a perspective view of the flat belt which concerns on other embodiment. It is a figure which shows the pulley layout of the belt running tester for abnormal noise evaluation at the time of being wet. It is a figure which shows the pulley layout of the belt running tester for heat resistance durability evaluation.

Hereinafter, embodiments will be described in detail with reference to the drawings.

(Embodiment 1)
1 and 2 show a V-ribbed belt B (friction transmission belt) according to the first embodiment. The V-ribbed belt B according to the first embodiment is, for example, an endless belt used for a belt transmission device for driving an auxiliary machine provided in an engine room of an automobile. The V-ribbed belt B according to the first embodiment has, for example, a belt length of 700 to 3000 mm, a belt width of 10 to 36 mm, and a belt thickness of 4.0 to 5.0 mm.

The V-ribbed belt B according to the first embodiment has a V layer formed in a triple layer including a compression rubber layer 11 forming a pulley contact portion on the inner peripheral side of the belt, an intermediate adhesive rubber layer 12, and a back rubber layer 13 on the outer peripheral side of the belt. A ribbed belt body 10 is provided. A core wire 14 arranged so as to form a spiral having a pitch in the belt width direction is embedded in an intermediate portion in the thickness direction of the adhesive rubber layer 12 of the V-ribbed belt body 10. The compression rubber layer 11 has a thickness of 1.0 to 3.6 mm, the adhesive rubber layer 12 has a thickness of 1.0 to 2.5 mm, and the back rubber layer 13 has a thickness of 0.4, for example. ~ 0.8 mm. The back rubber layer 13 may be replaced by a back reinforcing cloth.

The compressed rubber layer 11 is provided so that the plurality of V ribs 15 hang down toward the inner circumferential side of the belt. Each of the plurality of V ribs 15 is formed as a protrusion having a substantially inverted triangular cross section and extends in the belt length direction, and is arranged in parallel in the belt width direction. Each V rib 15 has, for example, a rib height of 2.0 to 3.0 mm and a width between base ends of 1.0 to 3.6 mm. The number of V ribs is, for example, 3 to 6 (6 in FIG. 1).

The compressed rubber layer 11 is a rubber composition in which a rubber component is crosslinked by heating and pressurizing an uncrosslinked rubber composition in which various compounding agents including layered silicate and aramid powder are mixed and kneaded. Has been formed. Therefore, the rubber composition forming the compressed rubber layer 11 contains a crosslinked rubber component and various compounding agents including layered silicate and aramid powder.

Examples of the rubber component of the rubber composition forming the compressed rubber layer 11 include ethylene-propylene-diene terpolymer (hereinafter referred to as “EPDM”), ethylene-propylene copolymer (EPM), ethylene-butene copolymer (EDM), Ethylene-α-olefin elastomers such as ethylene-octene copolymer (EOM); chloroprene rubber (CR); chlorosulfonated polyethylene rubber (CSM); hydrogenated acrylonitrile rubber (H-NBR) and the like. As the rubber component, it is preferable to use one kind or a mixture of two or more kinds thereof, it is preferable to use an ethylene-α-olefin elastomer, and it is more preferable to use EPDM.

When the rubber component of the rubber composition forming the compressed rubber layer 11 is an ethylene-α-olefin elastomer, its ethylene content is preferably 50% by mass or more, more preferably 55% by mass or more, and further preferably 57% by mass. It is at least 70% by mass, preferably 60% by mass or less, more preferably 59% by mass or less.

When the rubber component of the rubber composition forming the compressed rubber layer 11 is EPDM, examples of the diene component include ethylidene nobornene (ENB), dicyclopentadiene, and 1,4-hexadiene. Of these, ethylidene nobornene is preferable as the diene component.

When the rubber component of the rubber composition forming the compressed rubber layer 11 is EPDM and the diene component thereof is ethylidene nobornene, its ENB content is preferably 0.5% by mass or more, more preferably 4% by mass. As described above, the content is more preferably 4.4% by mass or more, preferably 10% by mass or less, more preferably 6% by mass or less, and further preferably 4.6% by mass or less.

The Mooney viscosity at 125° C. of the ethylene-α-olefin elastomer in the rubber component of the rubber composition forming the compressed rubber layer 11 is preferably 15 ML ₁₊₄ (125° C.) or more, more preferably 18 ML ₁₊₄ (125° C.) or more. , also preferably _75ML 1 + 4 (125 ℃) or less, more preferably _70ML 1 + 4 (125 ℃) or less, more preferably _20ML 1 + 4 (125 ℃) or less. The Mooney viscosity is measured based on JISK6300.

Examples of the layered silicate include smectite group, vermureite group, and kaolin group. Examples of the smectite group include montmorillonite, beidellite, saponite, and hectorite. Examples of the vermiculite group include trioctahedral vermulite and dioctahedral vermulite. Examples of the kaolin group include kaolinite, dickite, halloysite, lizardite, amesite, chrysotile and the like. As the layered silicate, it is preferable to use one kind or two or more kinds thereof, it is more preferable to use the smectite group, and it is further preferable to use montmorillonite.

It is preferable that the rubber composition forming the compressed rubber layer 11 contains fine flake-like layered silicate dispersed therein. The average particle size of the flaky layered silicate is preferably 1 μm or more, more preferably 5 μm or more, and preferably 100 μm or less, more preferably 50 μm or less. The average particle size of the flaky layered silicate is obtained by the number average of 50 to 100 maximum outer diameters measured by an image. The content (A) of the layered silicate in the rubber composition forming the compressed rubber layer 11 is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, still more preferably 10 parts by mass with respect to 100 parts by mass of the rubber component. The amount is not less than 100 parts by mass, preferably not more than 100 parts by mass, more preferably not more than 50 parts by mass, still more preferably not more than 25 parts by mass.

The "aramid powder" in the present application is a powdery or granular aromatic polyamide, and is derived from aramid fibers such as so-called aramid fibers that are secondarily processed short fibers or those that are further tertiary processed to be fibrillated. Does not include. Examples of the aromatic polyamide that constitutes the aramid powder include para-type aromatic polyamide and meta-type aromatic polyamide. Of these, the former para-type aromatic polyamide is preferable. Examples of the para-aromatic polyamide constituting the aramid powder include polyparaphenylene terephthalamide, and a copolymer of polyparaphenylene terephthalamide and diaminophenylene terephthalamide. Among them, the former polyparaphenylene terephthalamide The aramid powder is preferably dispersed and contained in the rubber composition forming the compressed rubber layer 11. The average particle size of the aramid powder is preferably 20 μm or more, more preferably 35 μm or more, and preferably 100 μm or less, more preferably 85 μm or less. The average particle diameter of the aramid powder is determined by the number average of 50 to 100 maximum outer diameters measured by an image. The content (B) of the aramid powder in the rubber composition forming the compressed rubber layer 11 is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and further preferably 10 parts by mass with respect to 100 parts by mass of the rubber component. And more preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 15 parts by mass or less.

In the rubber composition forming the compressed rubber layer 11, the content (A) of the layered silicate relative to 100 parts by mass of the rubber component is the content of the aramid powder from the viewpoint of obtaining a very high noise reduction effect and excellent durability. It is preferably larger than the amount (B). The ratio (A/B) of the content (A) of the layered silicate to the content (B) of the aramid powder relative to 100 parts by mass of the rubber component in the rubber composition forming the compressed rubber layer 11 is preferably 0.1 or more. , More preferably 0.15 or more, still more preferably 0.2 or more, preferably 10 or less, more preferably 6 or less, still more preferably 5 or less.

In the rubber composition forming the compressed rubber layer 11, the sum (A+B) of the content (A) of the layered silicate and the content (B) of the aramid powder is preferably 5 with respect to 100 parts by mass of the rubber component. The amount is not less than 10 parts by mass, more preferably not less than 10 parts by mass, preferably not more than 100 parts by mass, more preferably not more than 70 parts by mass, still more preferably not more than 55 parts by mass.

Examples of the compounding agent include a reinforcing material such as carbon black, a vulcanization aid, a crosslinking agent, and a vulcanization accelerator.

As the reinforcing material, in the case of carbon black, for example, channel black; SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234, etc. furnace black; FT, MT, etc. Thermal black; acetylene black and the like. Examples of the reinforcing material also include silica. As the reinforcing material, it is preferable to use one or more of these, and it is more preferable to use FEF alone.

The content (C) of the reinforcing material is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and preferably 80 parts by mass or less, more preferably 60 parts by mass with respect to 100 parts by mass of the rubber component. Below the section.

In the rubber composition forming the compressed rubber layer 11, the content (C) of the reinforcing material (carbon black) relative to 100 parts by mass of the rubber component is the content (A) of the layered silicate from the viewpoint of obtaining excellent durability. It is preferably more than The ratio (C/A) of the content (C) of the reinforcing material (carbon black) to the content (A) of the layered silicate per 100 parts by mass of the rubber component in the rubber composition forming the compressed rubber layer 11 is preferably Is 1 or more, more preferably 2 or more, and preferably 20 or less, more preferably 10 or less.

From the viewpoint of obtaining a very high noise reduction effect and excellent durability, the content (C) of the reinforcing material (carbon black) relative to 100 parts by mass of the rubber component is larger than the content (B) of the aramid powder. Is preferred. The ratio (C/B) of the content (C) of the reinforcing material (carbon black) to the content (B) of the aramid powder relative to 100 parts by mass of the rubber component in the rubber composition forming the compressed rubber layer 11 is preferably It is 1.5 or more, more preferably 1.7 or more, and preferably 20 or less, more preferably 10 or less.

From the viewpoint of obtaining excellent durability, the content (C) of the reinforcing material (carbon black) relative to 100 parts by mass of the rubber component is the sum of the content (A) of the layered silicate and the content (B) of the aramid powder. It is preferably more than (A+B). Of the content (C) of the reinforcing material (carbon black) with respect to 100 parts by mass of the rubber component in the rubber composition forming the compressed rubber layer 11 and the content (B) of the aramid powder. The ratio (C/(A+B)) to the sum (A+B) is preferably 0.5 or more, more preferably 0.9 or more, and preferably 10 or less, more preferably 5 or less.

Examples of the vulcanization aid include metal oxides such as zinc oxide (zinc white) and magnesium oxide. As the vulcanization aid, it is preferable to use one or more of these. The content of the vulcanization aid is, for example, 1 to 10 parts by mass with respect to 100 parts by mass of the rubber component.

Examples of the cross-linking agent include sulfur and organic peroxides. As the crosslinking agent, sulfur may be used alone, organic peroxide may be used alone, or both of them may be used in combination. In the case of sulfur, the compounding amount of the crosslinking agent is, for example, 0.5 to 4 parts by mass with respect to 100 parts by mass of the rubber component, and in the case of the organic peroxide, for example, 0.5 to 4 parts by mass with respect to 100 parts by mass of the rubber component. 8 parts by mass.

Examples of the vulcanization accelerator include metal oxides, metal carbonates, fatty acids and their derivatives. As the vulcanization accelerator, it is preferable to use one or more of these. The content of the vulcanization accelerator is, for example, 0.5 to 8 parts by mass with respect to 100 parts by mass of the rubber component.

The rubber composition forming the compressed rubber layer 11 preferably does not contain short fibers. However, short fibers may be contained within a range that does not impair the noise generation reduction effect and the excellent durability effect due to the inclusion of the layered silicate and aramid powder.

The adhesive rubber layer 12 is formed in a strip shape having a horizontally long rectangular cross section. The back rubber layer 13 is also formed in a strip shape having a horizontally long rectangular cross section. The surface of the back rubber layer 13 is preferably formed in a form in which the texture of the woven cloth is transferred from the viewpoint of suppressing the sound generated between the back rubber layer 13 and the contacting flat pulley.

Each of the adhesive rubber layer 12 and the back rubber layer 13 is formed of a rubber composition obtained by heating and pressurizing an uncrosslinked rubber composition obtained by mixing various compounding agents in a rubber component and kneading the mixture. ing. Therefore, each of the adhesive rubber layer 12 and the back rubber layer 13 contains a crosslinked rubber component and various compounding agents. The back rubber layer 13 is preferably formed of a rubber composition that is slightly harder than the adhesive rubber layer 12 from the viewpoint of suppressing the occurrence of sticking due to contact with the flat pulley.

Examples of the rubber component of the rubber composition forming the adhesive rubber layer 12 and the back rubber layer 13 include ethylene-α-olefin elastomer, chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), hydrogenated acrylonitrile rubber ( H-NBR) and the like, but preferably the same rubber component as that of the compressed rubber layer 11.

Similar to the compressed rubber layer 11, examples of the compounding agent include a reinforcing material such as carbon black, a vulcanization aid, a cross-linking agent, a vulcanization accelerator, and a rubber compounding resin.

The compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 may be formed of a rubber composition having the same composition, or may be formed of a rubber composition having a different composition.

The core wire 14 is composed of a twisted yarn such as polyester fiber (PET), polyethylene naphthalate fiber (PEN), aramid fiber, and vinylon fiber. The diameter of the core wire 14 is, for example, 0.5 to 2.5 mm, and the dimension between the centers of the core wires 14 adjacent to each other in the cross section is, for example, 0.05 to 0.20 mm. The core wire 14 is subjected to an adhesive treatment that is heated after being immersed in an RFL aqueous solution before molding and/or after being immersed in rubber paste and then dried in order to impart adhesiveness to the adhesive rubber layer 12 of the V-ribbed belt body 10. Adhesive treatment is performed.

According to the V-ribbed belt B according to Embodiment 1 having the above-described configuration, the rubber composition forming the compressed rubber layer 11 forming the pulley contact portion on the inner peripheral side of the belt contains the layered silicate and the aramid powder. As will be shown in Examples described later, it is possible to obtain a very high effect of reducing the generation of abnormal noise when exposed to water and to obtain excellent durability.

Next, a method of manufacturing the V-ribbed belt B according to the first embodiment will be described.

In the manufacture of the V-ribbed belt B according to the first embodiment, as shown in FIGS. 3 and 4, a belt forming die 20 provided with a cylindrical inner die 21 and an outer die 22, which are concentrically provided, is used.

In this belt mold 20, the inner mold 21 is made of a flexible material such as rubber. The outer die 22 is made of a rigid material such as metal. The inner peripheral surface of the outer die 22 is configured as a molding surface, and the V-rib forming grooves 23 are provided on the inner peripheral surface of the outer die 22 at a constant pitch in the axial direction. Further, the outer mold 22 is provided with a temperature control mechanism for circulating a heat medium such as water vapor or a coolant such as water to control the temperature. The belt mold 20 is provided with a pressurizing means for pressurizing and expanding the inner mold 21 from the inside.

In the production of the V-ribbed belt B according to the first embodiment, first, each compounding agent is blended with a rubber component and kneaded with a kneader such as a kneader or a Banbury mixer, and the obtained uncrosslinked rubber composition is formed into a sheet by calendering or the like. To form an uncrosslinked rubber sheet 11' for the compressed rubber layer 11. The layered silicate and aramid powder are blended in the uncrosslinked rubber sheet 11' for the compressed rubber layer 11. Similarly, the uncrosslinked rubber sheets 12' and 13' for the adhesive rubber layer and the back rubber layer are also prepared. In addition, the twisted yarn 14' for the core wire is immersed in the RFL aqueous solution to perform the adhesive treatment, and then the adhesive process is immersed in the rubber paste and dried by heating.

Then, as shown in FIG. 5, a cylindrical sleeve 24 having a smooth surface is covered with a rubber sleeve 25, and an uncrosslinked rubber sheet 13′ for the back rubber layer and an uncrosslinked rubber sheet for the adhesive rubber layer are provided thereon. 12' are sequentially wound and laminated, and the twisted yarn 14' for the core wire is spirally wound on the cylindrical inner mold 21 from above, and further, the uncrosslinked rubber sheet 12' for the adhesive rubber layer is further wound thereon. Then, the uncrosslinked rubber sheet 11′ for the compressed rubber layer is wound in order to form a laminated body B′. At this time, the uncrosslinked rubber sheets 11', 12', 13' are wound so that the grain direction is the belt length direction (circumferential direction).

Next, the rubber sleeve 25 provided with the laminated body B'is removed from the cylindrical drum 24, and as shown in FIG.

Then, as shown in FIG. 7, the inner mold 21 is positioned and sealed in the rubber sleeve 25 set in the outer mold 22.

Subsequently, the outer mold 22 is heated, and high pressure air or the like is injected into the sealed inside of the inner mold 21 to apply pressure. At this time, as shown in FIG. 8, the inner mold 21 expands and the uncrosslinked rubber sheets 11′, 12′, 13′ for forming the belt of the laminate B′ are compressed on the molding surface of the outer mold 22, Further, the cross-linking of these rubber components progresses and is integrated, and at the same time, the rubber component is compounded with the twisted yarn 14', and finally the cylindrical belt slab S is molded. The molding temperature of the belt slab S is, for example, 100 to 180° C., the molding pressure is, for example, 0.5 to 2.0 MPa, and the molding time is, for example, 10 to 60 minutes.

Then, the inside of the inner mold 21 is decompressed to release the seal, the belt slab S molded between the inner mold 21 and the outer mold 22 via the rubber sleeve 25 is taken out, and the belt slab S is sliced into a predetermined width. The V-ribbed belt B is obtained by turning the inside out. If necessary, the outer peripheral side of the belt slab S, that is, the surface on the V rib 15 side may be polished.

FIG. 9 shows a pulley layout of an accessory drive belt transmission 30 for an automobile using the V-ribbed belt B according to the first embodiment. The accessory drive belt transmission device 30 is of a serpentine drive type in which the V-ribbed belt B is wound around six pulleys of four rib pulleys and two flat pulleys to transmit power.

In this accessory drive belt transmission device 30, a rib pulley power steering pulley 31 is provided at the uppermost position, and a rib pulley AC generator pulley 32 is provided below the power steering pulley 31. A flat pulley tensioner pulley 33 is provided on the lower left side of the power steering pulley 31, and a flat pulley water pump pulley 34 is provided below the tensioner pulley 33. Further, a rib pulley crankshaft pulley 35 is provided on the lower left side of the tensioner pulley 33, and a rib pulley air conditioner pulley 36 is provided on the lower right side of the crankshaft pulley 35. These pulleys are made of, for example, metal pressed products, castings, and resin molded products such as nylon resin and phenol resin, and have a pulley diameter of 50 to 150 mm.

In this accessory drive belt transmission device 30, the V-ribbed belt B is wound around the power steering pulley 31 so that the V-rib 15 side comes into contact, and then wound around the tensioner pulley 33 so that the belt back side comes into contact. , Is wound around the crankshaft pulley 35 and the air conditioner pulley 36 in order so that the V rib 15 side comes into contact with the water pump pulley 34 so that the back side of the belt comes into contact with the V rib 15 side. Is wound around the AC generator pulley 32 and finally returned to the power steering pulley 31. The belt span length, which is the length of the V-ribbed belt B spanned between the pulleys, is, for example, 50 to 300 mm. The possible misalignment between pulleys is 0-2°.

(Embodiment 2)
10 and 11 show a V-ribbed belt B according to the second embodiment. The parts having the same names as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

In the V-ribbed belt B according to the second embodiment, the compression rubber layer 11 has a surface rubber layer 11a and an inner rubber portion 11b. The surface rubber layer 11a is made of porous rubber, is provided in layers along the entire surface of the V rib 15, and constitutes a pulley contact portion on the inner peripheral side of the belt. The thickness of the surface rubber layer 11a is, for example, 50 to 500 μm. The inner rubber portion 11b is made of solid rubber, is provided inside the surface rubber layer 11a, and constitutes a portion of the compressed rubber layer 11 other than the surface rubber layer 11a.

Here, the “porous rubber” in the present application means a crosslinked rubber composition having a large number of hollow portions inside and a large number of concave holes 16 on the surface, in which the hollow portions and the concave holes 16 are dispersed. And the structure in which the hollow portion and the concave hole 16 communicate with each other. In addition, the “solid rubber” in the present application means a crosslinked rubber composition that does not include hollow portions and concave holes 16 other than “porous rubber”.

The surface rubber layer 11a is formed of a rubber composition containing a crosslinked rubber component and various compounding agents containing layered silicate and aramid powder, as in the compressed rubber layer 11 in the first embodiment. Since the surface rubber layer 11a is made of porous rubber in addition to it, unexpanded hollow particles and/or a foaming agent for forming the porous rubber are mixed in the uncrosslinked rubber composition before formation thereof.

Examples of the unexpanded hollow particles include particles in which a solvent is enclosed inside a shell formed of a thermoplastic polymer (eg, acrylonitrile-based polymer). The hollow particles may be used alone or in combination of two or more. The content of the hollow particles is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass, relative to 100 parts by mass of the rubber component. It is the following. Examples of the foaming agent include an ADCA-based foaming agent containing azodicarbonamide as a main component, a DPT-based foaming agent containing dinitrosopentamethylenetetramine as a main component, and p,p′-oxybisbenzenesulfonylhydrazide as a main component. Examples include organic foaming agents such as OBSH foaming agents and HDCA foaming agents containing hydrazodicarbonamide as a main component. As the foaming agent, it is preferable to use one or more of these. The blending amount of the foaming agent is preferably 0.5 parts by mass or more, more preferably 4 parts by mass or more, and preferably 10 parts by mass or less, more preferably 7 parts by mass with respect to 100 parts by mass of the rubber component. It is the following.

Since the surface rubber layer 11a is a porous rubber, a large number of concave holes 16 are formed on the surface thereof. The average hole diameter of the concave holes 16 is preferably 40 μm or more, more preferably 80 μm or more, and preferably 150 μm or less, more preferably 120 μm or less. The average hole diameter of the concave holes 16 is obtained by the number average of 50 to 100 holes measured on the surface image.

The inner rubber portion 11b is formed of a rubber composition containing a crosslinked rubber component and various compounding agents. The rubber composition forming the inner rubber portion 11b may be the same as the rubber composition forming the surface rubber layer 11a excluding the hollow portion and the concave hole 16. The rubber composition forming the inner rubber portion 11b may be the same as the rubber composition forming the adhesive rubber layer 12 or the back rubber layer 13.

According to the V-ribbed belt B according to the second embodiment having the above configuration, the rubber composition forming the surface rubber layer 11a of the compression rubber layer 11 forming the pulley contact portion on the inner peripheral side of the belt is composed of layered silicate and aramid powder. By containing, it is possible to obtain a very high effect of reducing the generation of abnormal noise when exposed to water, and it is possible to obtain excellent durability. Moreover, although the rubber composition forming the surface rubber layer 11a is a porous rubber and the probability of crack occurrence is expected to be high, excellent durability can be obtained.

In order to manufacture the V-ribbed belt B according to the second embodiment, the uncrosslinked rubber sheets 11a' and 11b' for the surface rubber layer and the inner rubber portion of the compression rubber layer 11 are prepared. Hollow particles and/or a foaming agent are compounded in the uncrosslinked rubber sheet 11a' for the surface rubber layer. Then, as shown in FIG. 12, by the same method as that of the first embodiment, the rubber sleeve 25 covered on the cylindrical drum 24 having a smooth surface is covered with the uncrosslinked rubber sheet 13′ for the back rubber layer and the adhesive rubber. An uncrosslinked rubber sheet 12 ′ for layers is sequentially wound and laminated, and a twisted yarn 14 ′ for a core wire is spirally wound around the cylindrical inner mold 21 from above, and further from above, for an adhesive rubber layer. The uncrosslinked rubber sheet 12′, the uncrosslinked rubber sheet 11b′ for the inner rubber portion of the compressed rubber layer 11, and the uncrosslinked rubber sheet 11a′ for the surface rubber layer are sequentially wound to form a laminate B′. Then, a cylindrical belt slab S as shown in FIG. 13 is molded from this laminated body B'.

The other configurations and operational effects are the same as those of the first embodiment.

(Embodiment 3)
14 and 15 show a V-ribbed belt B according to the third embodiment. The parts having the same names as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

In the V-ribbed belt B according to the third embodiment, the compression rubber layer 11 has a surface rubber layer 11a and an inner rubber portion 11b. The surface rubber layer 11a is made of porous rubber, is provided along the outer side surface of each of the V ribs 15 on both sides, and the side surfaces of the pair of adjacent V ribs 15 facing each other and those facing each other. It is provided along the bottom of the connecting ribs and constitutes the pulley contact portion on the inner peripheral side of the belt. The latter surface rubber layer 11a has an inverted U-shaped cross section. Therefore, each surface rubber layer 11a is provided so as to include the outer side surface portion of each of the V ribs 15 on both sides or the facing side surface portion of the pair of V ribs 15 adjacent to each other. The thickness of the surface rubber layer 11a is, for example, 50 to 500 μm. The inner rubber portion 11b is made of solid rubber, is provided inside the surface rubber layer 11a, and constitutes a portion of the compressed rubber layer 11 other than the surface rubber layer 11a.

In order to manufacture the V-ribbed belt B according to the second embodiment, a cylindrical belt slab S as shown in FIG. 16 is molded by the same method as in the second embodiment. On the outer periphery of the belt slab S, there are formed projections 15' having a substantially trapezoidal cross section extending in the circumferential direction so as to be continuous in the axial direction, and the surface layer thereof is formed of porous rubber 11a" and other than that. The inside is made of solid rubber 11b″. Then, as shown in FIG. 17, the belt slab S is spanned between the pair of slab spanning shafts 26, and a V-rib-shaped groove extending in the circumferential direction is continuously provided in the axial direction of the outer periphery of the outer periphery of the belt slab S. The grinding wheel 27 thus abutted is rotated and brought into contact, and the belt slab S is also rotated between the pair of slab spanning shafts 26. At this time, as shown in FIG. 18, a plurality of V ribs 15 are formed by grinding the ridges on the outer periphery of the belt slab S. In these plurality of V ribs 15, the surface rubber layer 11a of porous rubber and An inner rubber portion 11b of solid rubber is configured.

Other configurations and operational effects are the same as those of the first and second embodiments.

(Other embodiments)
Although the V-ribbed belt B is shown in the above-described first to third embodiments, the present invention is not particularly limited to this, and in the case of a friction transmission belt, for example, a pulley contact portion on the belt inner peripheral side as shown in FIG. 19A is used. It may be a low edge type V belt B having a compression rubber layer 11 constituting the flat belt B having an inner rubber layer 17 constituting a pulley contact portion on the belt inner peripheral side as shown in FIG. 19B. May be.

(V-ribbed belt)
V-ribbed belts having the same configurations as in the above-described Embodiment 2 of Examples 1 to 5 and Comparative Examples 1 to 10 below were produced. The respective configurations are also shown in Tables 1 to 3.

<Example 1>
EPDM (trade name: EP123, ethylene content 58% by mass, ENB content 4.5% by mass, Mooney viscosity 19.5ML ₁₊₄ (125° C.)) as a rubber component was put into the chamber of a closed Banbury mixer. Mastication, then 50 parts by mass of a reinforcing material FEF carbon black (trade name: Seast SO manufactured by Tokai Carbon Co., Ltd.), 100 parts by mass of this rubber component, zinc oxide as a vulcanization aid (Sakai Chemical Co., Ltd.) Kogyo Co., Ltd. product name: 3 types of zinc oxide, 5 parts by mass, sulfur as a cross-linking agent (product name: Seimi OT, manufactured by Nippon Kyokusho Co., Ltd.: 2 parts by mass), sulfenamide vulcanization accelerator (Ouchi Shinko Chemical Co., Ltd.) Product name: Nocceller MSA-G) 2 parts by mass, first thiuram-based vulcanization accelerator (manufactured by Ouchi Shinko Chemical Co., Ltd. Product name: Noxeller TET-G) 0.5 part by mass, second thiuram-based vulcanization accelerator ( Ouchi Shinko Chemical Co., Ltd. product name: Nocceller TBT 1 part by mass, bentonite (Hojun Co. product name: Hotaka, montmorillonite content 50% by mass) 50 parts by mass (montmorillonite 25 parts by mass), aramid powder (Teijin company product Name: TW5011) 5 parts by mass, hollow particles (manufactured by Sekisui Chemical Co., Ltd. product name: Advancel EM403) 2 parts by mass, and foaming agent (manufactured by Sankyo Kasei Co., Ltd. product name: SELMIC CE) 7 parts by mass. A V-ribbed belt having a surface rubber layer of a compression rubber layer formed by kneading and using the obtained uncrosslinked rubber composition was prepared as Example 1.

The inner rubber portion of the compressed rubber layer, the adhesive rubber layer and the back rubber layer were formed of another rubber composition containing EPDM as a rubber component. Further, the core wire is composed of a twisted yarn made of polyethylene terephthalate fiber. The belt circumference was 1200 mm, the belt width was 10.68 mm, the belt thickness was 4.3 mm, and the number of ribs was 3.

<Example 2>
Using an uncrosslinked rubber composition obtained in the same manner as in Example 1 except that the amount of bentonite compounded was 10 parts by mass (5 parts by mass of montmorillonite) based on 100 parts by mass of the rubber component, a compressed rubber layer was prepared. A V-ribbed belt having a surface rubber layer formed thereon was prepared as Example 2.

<Example 3>
Uncrosslinked rubber obtained in the same manner as in Example 1 except that the amounts of bentonite and aramid powder were 30 parts by mass (15 parts by mass of montmorillonite) and 10 parts by mass, respectively, relative to 100 parts by mass of the rubber component. A V-ribbed belt having a surface rubber layer of a compression rubber layer formed using the composition was prepared as Example 3.

<Example 4>
The surface rubber layer of the compressed rubber layer was formed using the uncrosslinked rubber composition obtained in the same manner as in Example 1 except that the amount of the aramid powder was 30 parts by mass with respect to 100 parts by mass of the rubber component. The manufactured V-ribbed belt was manufactured and referred to as Example 4.

<Example 5>
Using a non-crosslinked rubber composition obtained in the same manner as in Example 4 except that the amount of bentonite compounded was 10 parts by mass (5 parts by mass of montmorillonite) relative to 100 parts by mass of the rubber component, a compressed rubber layer was prepared. A V-ribbed belt having a surface rubber layer formed thereon was prepared as Example 5.

<Comparative Examples 1 to 5>
Example 1 except that bentonite was not blended and the blending amount of the aramid powder was 3 parts by mass, 5 parts by mass, 10 parts by mass, 30 parts by mass, and 40 parts by mass with respect to 100 parts by mass of the rubber component. V-ribbed belts each having a surface rubber layer of a compression rubber layer formed using the uncrosslinked rubber composition obtained in the same manner were set as Comparative Examples 1 to 5, respectively.

<Comparative Examples 6 to 10>
Without blending the aramid powder, the blending amount of bentonite is 5 parts by mass (2.5 parts by mass of montmorillonite), 10 parts by mass (5 parts by mass of montmorillonite), 30 parts by mass (15 parts by mass of montmorillonite) per 100 parts by mass of the rubber component. ), 50 parts by mass (25 parts by mass of montmorillonite), and 60 parts by mass (30 parts by mass of montmorillonite) except that the uncrosslinked rubber composition obtained in the same manner as in Example 1 was used to form a compressed rubber layer. V-ribbed belts each having a surface rubber layer formed were prepared and designated as Comparative Examples 6 to 10.

In Tables 1 to 3, for each V-ribbed belt of Examples 1 to 5 and Comparative Examples 1 to 10, the content of montmorillonite per 100 parts by mass of the rubber component in the rubber composition forming the surface rubber layer of the compression rubber layer ( A) and the content (B) of the aramid powder (A+B), the ratio of the content (A) of the montmorillonite to the content (B) of the aramid powder (A/B), the content of the FEF carbon black ( C) ratio to montmorillonite content (A) (C/A), ratio of FEF carbon black content (C) to aramid powder content (B) (C/B), and FEF carbon black content The ratio (C/(A+B)) to the sum (A+B) of the content (A) of the content (C) of montmorillonite and the content (B) of the aramid powder is also shown.

(Test method)
<Evaluation of abnormal noise when exposed to water>
FIG. 20A shows a pulley layout of the belt running tester 40 for abnormal noise evaluation when wet.

The belt running tester 40 for evaluating abnormal noise when wet includes a drive pulley 41 which is a rib pulley having a pulley diameter of 140 mm, and a first driven pulley 42 which is a rib pulley having a pulley diameter of 75 mm is provided on the right side of the drive pulley 41. A second driven pulley 43, which is a rib pulley having a pulley diameter of 50 mm, is provided above the first driven pulley 42 and to the upper right of the drive pulley 41, and further, the drive pulley 41 and the second driven pulley 43 are provided. An idler pulley 44, which is a flat pulley having a pulley diameter of 75 mm, is provided in the middle. Further, in the belt running tester 40 for evaluating abnormal noise when wet, the V-ribbed side of the V-ribbed belt B is in contact with the drive pulley 41, the first and second driven pulleys 42 and 43, and the backside is a flat pulley. A certain idler pulley 44 is contacted and wound around.

The V-ribbed belt B of each of Examples 1 to 5 and Comparative Examples 1 to 10 was set in the above-described running test machine 40 for abnormal noise when wet, and a pulley was applied such that a belt tension of 49 N was applied to each rib. Positioning is performed, and resistance is applied to the alternator to which the second driven pulley 43 is attached so that a current of 60 A flows, the drive pulley 41 is rotated at a rotation speed of 800 rpm at normal temperature, and the drive pulley 41 of the V-ribbed belt B is rotated. At the entrance portion to the V-ribbed belt B, water was dripped at a rate of 1000 ml per minute on the V-ribbed side. Then, regarding the occurrence of abnormal noise when the belt is running, "S: Abnormal noise is not recognized at all. A: Abnormal noise is slightly recognized. B: Abnormal noise is slightly recognized. : The occurrence of abnormal noise is clearly observed. D: The occurrence of severe abnormal noise is observed."

<Heat resistance durability evaluation>
FIG. 20B shows a pulley layout of the belt running tester 50 for evaluating heat resistance and durability.

The belt running tester 50 for evaluating heat resistance and durability has a large-diameter driven pulley 51 and a drive pulley 52, which are rib pulleys each having a pulley diameter of 120 mm, and are vertically spaced apart from each other. An idler pulley 53, which is a flat pulley with a diameter of 70 mm, is provided, and a small-diameter driven pulley 54, which is a rib pulley with a pulley diameter of 55 mm, is provided on the right side of the idler pulley 53. In the belt running tester 50 for evaluating heat resistance and durability, the V-rib side of the V-ribbed belt B contacts the large-diameter driven pulley 51, the drive pulley 52, and the small-diameter driven pulley 54 that are rib pulleys, and the back side is a flat pulley. The idler pulley 53 is configured to come into contact with and be wound around. The idler pulley 53 and the small-diameter driven pulley 54 are positioned so that the winding angle of the V-ribbed belt B is 90°.

Each of the V-ribbed belts B of Examples 1 to 5 and Comparative Examples 1 to 10 was set in the heat resistance and durability evaluation belt running tester 50, and a large-diameter driven pulley 51 was given a rotational load of 11.8 kW. A set weight of 834N was laterally applied to the small diameter driven pulley 54 so that tension was applied, and the drive pulley 52 was rotated at a rotation speed of 4900 rpm to run the belt under an ambient temperature of 120°C. Then, cracks were generated in the compressed rubber layer of the V-ribbed belt B, and the running time until the cracks reached the core wire was measured, and this was taken as the heat resistant durability life.

(Test results)
The test results are shown in Tables 4-6.

According to Tables 4 to 6, in the rubber composition forming the surface rubber layer of the compressed rubber layer, in Examples 1 to 5 containing the montmorillonite of the layered silicate and the aramid powder, the abnormal noise evaluation when exposed to water was S or. A, the heat-resistant durability life is 327 hours or more, the effect of reducing the generation of abnormal noise when exposed to water is very high, and the durability is excellent, while the comparison contains only one of the layered silicates montmorillonite and aramid powder. In Examples 1 to 10, it can be seen that there is no one that can obtain a very high effect of reducing the generation of abnormal noise when exposed to water, and some that cannot obtain excellent durability.

INDUSTRIAL APPLICABILITY The present invention is useful in the technical field of friction transmission belts.

B V ribbed belt, V belt, flat belt (friction transmission belt)
11 compression rubber layer 11a surface rubber layer 17 inner rubber layer

Claims (14)

A friction transmission belt having a rubber layer forming a pulley contact portion on the inner peripheral side of the belt,
The rubber layer is formed of a rubber composition containing a crosslinked rubber component, a layered silicate, and an aramid powder,
Carbon black as a reinforcing material is blended in the rubber composition, and in the rubber composition, the content of the reinforcing material with respect to 100 parts by mass of the rubber component is the content of the layered silicate and the aramid powder. Friction transmission belt more than the sum with the content. The friction transmission belt according to claim 1,
A friction transmission belt in which the content of the layered silicate in the rubber composition is 3 to 100 parts by mass with respect to 100 parts by mass of the rubber component. The friction transmission belt according to claim 1 or 2,
A friction transmission belt in which the content of the aramid powder in the rubber composition is 5 to 30 parts by mass with respect to 100 parts by mass of the rubber component. The friction transmission belt according to any one of claims 1 to 3,
A friction transmission belt in which the sum of the content of the layered silicate and the content of the aramid powder in the rubber composition is 100 parts by mass or less based on 100 parts by mass of the rubber component. The friction transmission belt according to any one of claims 1 to 4,
A friction transmission belt in which the rubber composition is porous rubber. The friction transmission belt according to any one of claims 1 to 5,
A friction transmission belt in which the sum of the content of the layered silicate and the content of the aramid powder in the rubber composition is 5 parts by mass or more based on 100 parts by mass of the rubber component. The friction transmission belt according to any one of claims 1 to 6,
In the rubber composition, a friction transmission belt in which the content of the layered silicate is greater than the content of the aramid powder with respect to 100 parts by mass of the rubber component. The friction transmission belt according to any one of claims 1 to 7,
A friction transmission belt in which the carbon black is FEF. The friction transmission belt according to any one of claims 1 to 8,
The content of the reinforcing material in the rubber composition is 30 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the rubber component. The friction transmission belt according to any one of claims 1 to 9,
A friction transmission belt, wherein the ratio of the content of the reinforcing material to the content of the layered silicate with respect to 100 parts by mass of the rubber component in the rubber composition is 1 or more and 20 or less. The friction transmission belt according to any one of claims 1 to 10,
In the rubber composition, a friction transmission belt in which the content of the reinforcing material relative to 100 parts by mass of the rubber component is larger than the content of the layered silicate. The friction transmission belt according to any one of claims 1 to 11,
A friction transmission belt in which the ratio of the content of the reinforcing material to the content of the aramid powder with respect to 100 parts by mass of the rubber component in the rubber composition is 1.5 or more and 20 or less. The friction transmission belt according to any one of claims 1 to 12,
In the rubber composition, a friction transmission belt in which the content of the reinforcing material relative to 100 parts by mass of the rubber component is larger than the content of the aramid powder. The friction transmission belt according to any one of claims 1 to 13,
A friction transmission belt, wherein the ratio of the content of the reinforcing material to the total of the content of the layered silicate and the content of the aramid powder is 10 or less with respect to 100 parts by mass of the rubber component in the rubber composition.

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